application specific intelligent power modules -a novel approach to system integration in low power...

8/10/2019 Application Specific Intelligent Power Modules -A Novel Approach to System Integration in Low Power Drives

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Application Specific Intelligent Power Modules - A Novel Approach toSystem Integration in Low Power Drives

Eric R. Motto- Powerex Inc., Youngwood, Pennsylvania, USA

ABSTRACT

Abstract - This paper reviews the system requirements and key technologies driving the

development of highly integrated Application Specific Intelligent Power Modules (ASIPMs). New

ASIPMs with power circuit topologies, control functions and packaging optimized to meet the

performance, cost and size requirements of specific small motor control applications will be

presented.

I. INTRODUCTION

When used with an inverter, three phase AC motors are smaller, more efficient and more reliablethan the universal AC and brush type DC motors that are commonly used in light industrial and consumer

applications. In order to realize these advantages, the cost of the inverter must be offset by energy savings,

improved performance, and increased reliability. The widespread use of inverters in heavy industrial and

precision motion control applications is evidence that these advantages are being realized. On the other

hand, the use of inverters with small AC motors (100W - 2.2kW) is often limited by the cost and complexity

of the inverter. In addition, limited space often prevents the use of general purpose inverters with fixed

shape, size, and cooling requirements. For these applications, it is becoming increasingly desirable to

simplify and miniaturize the power section so that the physical size, form factor, and cost requirements can

more easily be met. This paper will examine the

system requirements of some typical small motor

drive applications and present five examples of

Application Specific Intelligent Power Modules

(ASIPMs) targeted to address these requirements.The examples illustrate how power circuit

topologies, integrated functions, and packaging can

be optimized to meet the requirements of specific

applications.

II. THE ASIPM CONCEPT

Conventional IPMs (figure 1a) integrating

power devices with low voltage ASICs (Application

Specific Integrated Circuits) to provide gate drive

and protection functions have been widely accepted

for general purpose motor drive applications rangingfrom 200W to more than 150kW [3][5][7]. Thesuccess of these modules is the direct result of

several technical advantages including: (1) Reduced

design time and improved reliability offered by the

factory tested, built-in gate drive and protection

functions; (2) Lower losses resulting from

simultaneous optimization of power chips and

protection functions; (3) Smaller size resulting from

User Supplied Interface

Power Chips

LV ASIC

Over Current,Over Temp.,Cotrol supplyfailure

Gate Drive

Temp. Sensor

LV ASIC

Over Current,Control supplyfailure

Gate Drive

Isolated Control

Signal Interface(Opto Couplers)

Isolated PowerSupplyC

PU

HVIC

LV ASIC

Power Chips

LevelShift

Gate Drive andProtection

Input signalconditioning

Protection, Fault Logicand Analog CurrentFeedback Processing

GateDrive

CPU

Isolated ControlSignal Interface(Opto Couplers)

Isolated PowerSupply

Current sensor(s)Temp. sensor

Figure 1a: Conventional IPM

Figure 1b: ASIPM


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the use of bare power chips and application specific control ICs. (4)

Improved manufacturability resulting from lower external component

counts.

Figure 2: HVIC Chip

Unfortunately, in spite of these advantages, the conventional

IPMs generic, general purpose, design does not provide enough

functional integration to meet the demanding cost and size

requirements of some small motor control applications. In thesecases, it is often desirable to increase the level of integration to

include functions such as level shifting, high side power supplies and

current sensing. The ASIPM shown in figure 1b has been developed

to address these requirements. The ASIPM takes the integration a

step farther than conventional IPMs by introducing HVIC (High

Voltage Integrated Circuit) technology. The ASIPMs described in this

paper utilize custom high and low voltage integrated circuits to

provide input signal conditioning, protection logic, analog current

feedback signal processing, level

shifting and gate drive for the

integrated power semiconductor

devices. A photo of a typical high

voltage integrated circuit (HVIC) isshown in figure 2.

III. SELECTING THE INTEGRATED

CONTROL AND PROTECTION

FUNCTIONS

The addition of HVIC

technology to the ASIPM makes it

possible to integrate a wide range of

sophisticated functions. Figure 3 is a

block diagram showing some of the

functions that can be implemented.

In general, the cost and size of the

ASIPM increases with increasing

complexity. To determine which functions should be integrated for a given application, it is necessary to

consider the fundamental trade-off between performance, size and cost illustrated in figure 4. The key to

developing a cost effective ASIPM is to integrate only the functions that provide both system and cost

advantages. Table 1 gives a breakdown of the required functions in four different applications. By examining

the requirements shown in table 1 and considering the trade-off of figure 4 an optimum combination of

integrated functions can be realized. Clearly, the optimum combination will be different for different

applications. To date, five families of ASIPMs have been developed to meet the needs of specific

applications. These devices will be described in more detail

NRS

GateDrive

GateDrive

SC Prot.

SC Prot.

LevelShift

Shoot-ThroughInterlock

BootStrapSupply

UnderVoltage

Lock-Out

FaultStatus

Feedback

TSOverTemp.

Current

Sensor(s)

UnderVoltage

Lock-Out

U,V,W

P

Control

Power

CPU/DSP

Control

n

Status

n

AnalogCurrent

n

Figure 3: ASIPM Integrated Functions

PerformanceEfficiency

Control PrecisionI/O Functions

Reliability

CostFunctional Value

Development TimeManufacturability

SizeSystem

RequirementsForm Factor

Figure 4: ASIPM Design Trade-off

Inverter

IGBTs & Free Wheel Diodes

Converter

DiodesBrake

IGBT & Diode

Figure 5: ASIPM Power Circuit Requirements


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Table 1: ASIPM Control and Protection Application Requirements

Control and Protection

Functions

High Performance

General Purpose

Industrial Inverter

Compact High Precision

AC Servo and Vector

Drives

Basic General Purpose

Industrial and

Commercial Speed

Control/Smart Motors

Low Cost Consumer

Appliance and

imbedded inverters

Gate Drive Required Required Required Required

Level Shift Required Required Required Required

Boot Strap Supply

Diodes

Required Required Required Required

P-Side Gate Drive

Under Voltage

Protection

Required due to unstable nature

of boot strap supplies







P-Side Short Circuit

Protection

Desirable, but may not be

needed when high performance

output current sensors are used

with a high speed CPU

Desirable, but may not be

needed when high performance

output current sensors are used

with a high speed CPU

Desirable if low enough cost.

However, acceptable protection

can usually be achieved using

bus current sensors

Usually unnecessary in

imbedded inverter applications

N-Side Gate Drive

Under Voltage

Protection

Generally required for reliable

power up/down


power up/down


power up/down


power up/down

N-Side Short Circuit

Protection

Desirable for low impedance

faults and shoot-through survival


faults and shoot-through survival


faults and shoot-through survival.

May be implemented using bus

current sensor.


faults and shoot-through survival.

May be implemented using bus

current sensor

Shoot Through InterlockGood safety feature. May be

required depending on users

design philosophy

Good safety feature. May be

required depending on users

design philosophy

Good safety feature. May be

difficult to justify cost

Desirable, but may not meet cost

requirements

Over Temperature Desirable Desirable Desirable if cost effective Usually unnecessary inimbedded inverter applications

Current Sensors and

Feedback

Three phase output current

feedback is required

Three phase output current

feedback is required

DC Bus current feedback signal

is usually sufficient

Current feedback signal is

usually not required

Fault Status Feedback Multiple diagnostic fault signalsare desirable

Multiple diagnostic fault signals

are desirable

Single fault status signal is

usually acceptable

Single fault status signal is

usually acceptable

in the following sections.

IV. SELECTING THE POWER CIRCUIT TOPOLOGY

The power semiconductor requirements in the inverter power stage also differ from application toapplication. Figure 5 shows the typical power devices that may be included in a small motor control. Table 2

gives a breakdown of the requirements in four different applications. For lowest cost, the power stage should

only include the necessary power devices. It can be observed from table 2 that the optimum power circuit

topology depends on the application requirements.

V. ASIPM EXAMPLES

Table 2: ASIPM Power Circuit Requirements

Power Circuit

Component

High Performance

General Purpose

Industrial Inverter

Compact High Precision

AC Servo and Vector

Drives

Basic General Purpose

Industrial and

Commercial SpeedControl/Smart Motors

Low Cost Consumer

Appliance and

imbedded inverters

Converter (Rectifier) Usually requires three phaserectifier

Required for stand alone units

Not required in DC feed multi

axis applications

Usually requires three phase

rectifier

May require three phase, single

phase, or doubler* configurations

Brake Usually required for rapiddeceleration

Braking function generally

required but may be

implemented in the bulk power

supply of DC fed systems and

size requirements vary widely

depending on the application

Usually not required Usually not required

Inverter Required - High PWMFrequency (5kHz - 20kHz)

Required - High PWM

Frequency (5kHz - 20kHz)

Required - High PWM

Frequency (5kHz - 20kHz)

Required - High and Low PWM

frequencies


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The following subsections present five

examples of actual ASIPMs that have been

optimized to meet the needs of specific

applications. In each example the power circuit

topology, package design and integrated functions

have been tailored to a specific class of small

motor control applications. At the same time carehas been exercised to keep the integrated

functions as generic as possible so that the

module is suitable for a wide enough range of

applications to take advantage of the

economies of automated mass production.

These examples each follow one of the

application categories outlined in tables 1 and

2.

Figure 6: PS212XX DIP ASIPM

A. ASIPM "DIP Series" For Consumer

Appliance Applications

The "DIP" ASIPM, PS212XX series, is

designed for basic speed control in consumer

appliance applications. For these applications,

the ASIPM must provide a small, low-cost,

efficient power stage that can be easily

integrated into the finished equipment. In order

to achieve these targets, a new transfer

molded package was developed. A photograph of the

new package is shown in figure 6 and a cross section

diagram is shown in figure 7. Low cost is achieved by

assembling bare power chips along with custom HVIC

and LVIC die on a lead frame like a giant integrated

circuit. The lead frame assembly is molded in epoxy resin

along with an aluminum heat sink to provide good

thermal characteristics. This process reduces cost and

manufacturing time by eliminating the need for separate

packaging of the power devices and control ICs. In

addition, the IMS (Insulated Metal Substrate) or ceramic substrate that is

used in conventional hybrid modules is not required. The transfer molded

package is also well suited for high volume, low cost mass production.

Aluminum Heat SinkMold Resin

Power Chips

IGBT, FWDi

Al Bond Wire Au Bond WireHVIC

Power Pins Control Pins

Figure 7: DIP ASIPM Package Cross Section

Table 3: DIP ASIPMsDIP ASIPM Inverter Rating

Line-up 400W 750W 1500W

Low

Frequency

Type

PS21204 PS21205

High

Frequency

Type

PS21213 PS21214

The input voltage for these applications is generally between

100VAC and 240VAC. To cover this range, IGBTs and free wheel diodes

with a 600V VCESrating were selected. Most of the target applications are

powered from a single phase AC source but flexibility to accommodate

three phase sources and voltage doubler (figure 8) topologies wasdesired. Due to these requirements and the limited capabilities of the lead frame design, it was determined

that the rectifier converter should not be integrated in the DIP ASIPM. The IGBT inverter section is a

standard three phase bridge containing six IGBT+FWDi pairs. For optimum system cost, the decision was

made to develop two different types of IGBT chips. High speed chips are used when the application requires

switching frequencies greater than 5kHz and low speed (low saturation voltage) chips are used when the

required switching frequency is less than 5kHz. At this writing, there are four DIP ASIPMs in production and

several additional types under development. Table 3 shows the typical application and type names of these

four devices.

330

VDC120VAC

Figure 8: Doubler Circuit

Figure 9 is a block diagram showing the DIP ASIPMs integrated control and protection functions


5/15


6/15

under voltage lock out circuit. If the voltage of the control

supply falls below the UV level specified on the data sheet,

the low side IGBTs are turned off and a fault signal is

asserted. In addition, the p-side gate drive circuits have

independent under voltage lock out circuits to protect

against failure of the boot-strap power supplies.

The DIP ASIPM uses the voltage across anexternal shunt resistor inserted in the negative DC bus to

monitor the current and provide protection against overload

and short circuits. An RC filter with a time constant of 1.5 to

2s is inserted as shown in figure 9 to prevent erroneousfault detection due to di/dt induced noise at switching

events. When the voltage at the CIN pin exceeds the VSC

reference level specified on the device data sheet the lower

arm IGBTs are turned off and a fault signal is asserted at

the FO output. The IGBTs remain off until the fault time

(tFO) has expired and the input signal has cycled to its off

state. The duration of tFO is set by an external capacitor

CFO.

The DIP ASIPM has seven microprocessorcompatible input and output signals. All signals are 5V

TTL/CMOS compatible and referenced to the common ground

of the control power supply allowing direct connection to the

MCU. Figure 12 shows a typical external interface circuit. On

and off operations for all six IGBTs in the ASIPM are

controlled by the active low control inputs. Normally, these

inputs are pulled high to the 5V logic supply of the MCU with

an external resistor. The MCU commands the IGBT to turn on

by pulling the respective input low. Hysteresis is provided on

all inputs to prevent oscillations and enhance noise immunity.

The fault signal output is in an open collector configuration.

When a fault occurs the ASIPM pulls the fault line low.

(U,V,W)

GateDrive

(P)

(N)

GateDrive15V

Boot StrapSupply

Diode

+

Floating SupplyV(U,V,W)

+

+

ChargingPath

CIN(n)

CIN(n)

V(U,V,W)

Figure 11: Boot Strap Supply Operation

B. ASIPM "Version 3" For Basic General Purpose

Industrial Speed Control

(Smart Motors)

CPU/DSP

ASIPM

5V 15V

5.1K5.1K

6

+ +VD

UP, VP, WP,UN, VN, WN

FO

GND

Figure 12: DIP ASIPM

Interface Circuit

The version 3

PS1103X series of ASIPMs was

developed for applications such

as pumps, hoists, and conveyors

that require limited control

performance consisting primarily

of speed regulation. In theseapplications, it is often desirable

to miniaturize and simplify the

power stage so that the inverter

can be mounted on, or integrated into the motor. The version 3 series of ASIPMs consists of five types

designed for 0.2 to 2.2kW micro inverter applications. Table 4 summarizes the key characteristics of each of

the five module types in the PS1103X ASIPM family.

Table 4: Version 3 ASIPMs

Type Typical Motor

Rating (kW)

IGBT Rating

(IC/VCES)

Inverter Output

Current IO

(ARMS)

OC

Trip

(Amps)

Short Circuit

Level (SC)

(Amps)

PS11032 0.2/220VAC 4A/600V 1.5 5.3 8.0

PS11033 0.4/220VAC 8A/600V 3.0 10.6 16

PS11034 0.75/220VAC 15A/600V 5.0 17.7 30

PS11035 1.5/220VAC 20A/600V 7.0 24.7 40

PS11036 2.2/220VAC 30A/600V 11 39 60

The packaging selected for the version 3 ASIPM is a low profile design using an aluminum base

IMS (Insulated Metal Substrate) substrate. A photo of the version 3 ASIPM is shown in figure 13. A cross


7/15

section diagram of the low profile IMS package is shown in figure

14. The power chips, control IC and support components are

assembled on the IMS substrate much like a conventional

surface mount printed circuit board. This process is easily

automated, low cost and quite flexible.

Figure 13: PS1103X

Version 3 ASIPM

A block diagram of the version 3 ASIPM is shown in

figure 15. Careful selection of integrated functions and advancedprocessing technologies allowed a single HVIC to be used for the

gate drive and protection of all six IGBTs. This single IC design

yields low cost and extremely compact size. The ASIPMs

integrated functions are powered from a single 15V control power

supply referenced to the negative DC bus.

Built-in, boot strap circuits supply power for the high side

gate drive circuits eliminating the need for separate isolated

power supplies. Incorporating

the high side power supplies

and level shifting into the

ASIPM reduces high voltage

spacing requirements on thecontrol PCB allowing a

significant savings in circuit

board space.

The PS1103X version

3 ASIPMs power circuit

consists of six rectifier diodes

forming a three phase bridge

and six IGBT, free wheel diode

pairs forming a three phase

inverter stage. The brake circuit is not required for most of the target applications so it was omitted to reduce

the size and cost of the module. A circuit diagram of the power circuit is included in figure 15. Openings are

provided in both the positive and negative DC bus connections. All of the IGBT and free wheel diodes are

the latest Mitsubishi/Powerex third generation technology utilizing shallow diffusion and 2~3m design rules[1].

Multi Layer Insulated

Metal Substrate Silicon

Chips

Gate Drive and Control

Circuits

Aluminum Bond

Wires

Plastic

CasePower Terminals Epoxy

Resin

Signal

Terminals

Figure 14: Cross Section of IMS ASIPM Package

Built in short circuit and over current protection allow maximum utilization of power device capability

while avoiding nuisance tripping. This is achieved using a time dependent fault trip level. Figure 16 shows

the time dependence of the

over current and short circuit

protection functions. When a

severe low impedance fault

causes the current to exceed

more than two times the

modules ICrating, short circuit

protection is activated and

shut down occurs very quickly

~2s. Under overload

conditions, the trip time

extends to 10s. Over current

protection is activated when

the peak current indicates that

the load current has exceeded

250% of the modules IO(RMS)

rating.

Gate Drive

UV Lock Out

Level Shift

Gate Drive

UV Lock Out

Level Shift

Gate Drive

UV Lock Out

Level Shift

Gate Drive

UV

Lock Out

SC

Protection

Analog Current

Feedback

Input Signal

Conditioning

Interlock

Fault Output

Logic

+VCC

HV-ASIC

P1

R

S

T

N1

P2

U

V

W

N2

VD

UPVP

WPUNVN

WN

FO

VAMP

GND

5V LogicInterfaceto MCU

15V

230VAC

Motor

Figure 15: ASIPM Version 3 Block Diagram

A buffered analog bus


8/15

Typical ICWaveform

tW(s)0

2 10

ProtectionLevel

Short Circuittrip level

Over Currenttrip level

IC(A)

IC(rated)X 2

IORMS(rated)x

250% x 2

Figure 16: ASIPM Version 3 Short circuit

and over current protection function

VAMP(V)

1

0

3

4

5

2

0 100 200 300Bus Current (%) Normalized to IORMS(rated)x 2

Current Feedback Signal

Output Characteristic

Conditions:

VD=15V, Tj= 25C

VAMP(200%)

VAMP(100%)

Figure 17: ASIPM Version 3 Analog Bus

Current Feedback Signal Performance

VCIN(P)off

on

VCIN(N)

VGE(P)0

VGE(N)0

off

on

NormalOperation

N-Side erroneousnoise rejected

P-Side on commanddelayed until N-Side off

Active Low P-Sidecontrol input

Active Low N-Sidecontrol input

P-Side IGBT GateVoltage

N-Side IGBT GateVoltage

Figure 18: ASIPM Version 3 Shoot

Through Interlock Protectioncurrent feedback signal is provided for system

control. The signal is derived from a shunt that

measures the sum of the currents in the

emitters of the low side IGBTs (see figure 15).

The HVASIC amplifies the signal from the

shunt to provide a scaled analog feedback

signal of 4V when the peak load current

reaches a level equivalent to 200% of the

modules rated IO(RMS). Figure 17 shows the

characteristics of the analog feedback signal.

The HVASIC also provides shoot

through interlock logic for additional protection

against noise and control signal anomalies.

Figure 18 is a timing diagram showing theoperation of the interlock function. The interlock

function rejects input signals that command the

upper and lower IGBTs in a leg to be on

simultaneously. Operation of the interlock in the

version 3 ASIPM does not produce a fault

signal.

Table 5: Version 3 ASIPM Control SignalsSignal Name Designation Description

Control Inputs UP, VP, WP,

UN, VN, WN,

Inputs for controlling on/off

operation of the IGBTs in the IPM.

Fault Signal FO Fault output signal

Analog Current

Feedback

VAMP Analog current feedback signal

The module is protected from failure of

the 15V control power supply by a built in under voltage lock out

circuit. If the voltage of the control supply falls below the UV level

specified on the data sheet, the low side IGBTs are turned off

and a fault signal is asserted. In addition, the p-side gate drive

circuits have independent under voltage lock out protection to

protect against failure of the boot-strap power supplies.The PS1103X series ASIPM has eight microprocessor

compatible input and output signals. All signals are 5V

TTL/CMOS compatible and are referenced to the common

ground of the control power supply to allow direct connection to

the MCU. Table 5 summarizes the ASIPM's input and output

signal names and function definitions. Figure 19 shows a typical

external interface circuit for the version 3 ASIPM. On and off

operations for all six IGBTs in the ASIPM are controlled by the

CPU/DSP

ASIPM

5V 15V

5.1K5.1K

6

+ +

10K

0.1nF

VD


FO

VAMP

GND

Figure 19: ASIPM Version 3

Interface Circuit


9/15

active low control inputs. Normally,

these inputs are pulled high to the 5V

logic supply of the MCU with an

external 5.1K resistor. The MCUcommands the IGBT to turn on by

pulling the respective input low.

Hysteresis is provided on all inputs toprevent oscillations and enhance noise

immunity. The fault signal output is in

an open collector configuration. When

a fault occurs, the fault line pulls low. If

the fault is caused by an SC or OC

condition, the output asserts a fixed

1.8ms pulse. In the case of a UV lock

fault the signal is maintained until the control supply

returns to normal. An example of a compact inverter

designed around the version 3 ASIPM is shown in

figure 20.

Figure 20: Miniature motor drive using Version 3 ASIPM

C. ASIPM "Version 2" For Precision Vector and

AC Servo Drives

The "Version 2" ASIPM, PS1102X series is

designed for miniature high performance servo and

vector drives. In these applications, it is desirable to

integrate sophisticated control functions such as a

current limit warning and three phase analog current

feedback. The increased integration simplifies the power

stage and reduces its cost. A simplified power stage also

helps to improve the reliability of complex multi-axis motion

control systems. The version 2 series of ASIPMs consists

of five types designed for 50 to 750W servo drives or 200 to

2200W high performance inverters. Table 6 summarizes the

key characteristics of these devices.


Type Typical

Motor

Rating

(kW)

Inverter

Output

Current

(ARMS)

Peak Output

Current at

CL Warning

(AMPS)

Short Circuit

Protection

Level (SC)

(Amps)

PS11021 0.2 0.8 5.3 10

PS11022 0.4 1.5 10 20

PS11023 0.75 3.0 17 38

PS11024 1.5 5.0 25 40

PS11025 2.2 7.0 35 60

The packaging selected for the version 2 ASIPM is

the same low profile, aluminum base IMS utilized for version

3. A photo of the version 2 ASIPM is shown in figure 21.

A block diagram of the version 2 ASIPM is shown

in figure 22. In order to provide the sophisticated control

functions required for high performance applications, it was

necessary to use a LVASIC for the control and protection of

the low side IGBTs and a HVASIC for the level shift, gate

drive and protection of the high side IGBTs. Like the version 3

ASIPM the version 2 ASIPM has built in boot-strap supply circuitsand P and N side under voltage lock out.

Figure 21: PS1102X

Version 2 ASIPM

Figure 23: Matching Converter

Module for ASIPM

The version 2 ASIPM power circuit consists of six IGBTs

and six fast recovery free wheel diodes forming a three phase

inverter stage. The input rectifier was omitted because many of the

target applications are DC fed inverter modules for multiaxis

systems. For stand alone inverters a separate matching three

phase rectifier module is available. A photo of the matching rectifier

module is shown in figure 23. The braking circuit was not


10/15

R

S

T

CU CV CW CL FO UN VN WN UP VP WP GND VD

T

S

Gate Drive

UV Lock Out

Gate Drive

UV Lock Out

Level

Shift

Gate Drive

UV Lock Out

U

V

W

CBU- CBU+ CBV- CBV+ CBW- CBW+

Motor230VAC

5V Logic Interface to MCUAnalog Current Feedback15V

Control UV Prot ection

OT

Fault Logic

Gate Drive & Short Circuit ProtectionAnalog

Current

Signal

Processing

Matching ConverterModule - RM**TN-H

Figure 22: ASIPM Version 2 Block Diagram

integrated because the requirements of the target applications range from no brake in the case of regulated,

DC fed, multi-axis systems to very large braking devices in systems with heavy regeneration. A circuit

diagram of the power stage is included in figure 22.

In the version 2 ASIPM the low side IGBTs are protected from short circuit conditions by circuits

that monitor the current mirror outputs on the IGBT chips. If the current through the device exceeds the SC

level shown in table 6, the IGBT is immediately but softly turned off. The soft turn off is used to help minimize

transient voltages that can occur during an emergency shut down. The SC level is set at about three times

the IGBTs nominal rating. At this current level the IGBT is in imminent danger of being damaged so an

immediate shut down is warranted. If the short circuit protection is activated the module will assert a faultoutput signal. The short circuit protection is automatically reset when the fault timer (tFOexpires) and the

control input signal of the IGBT involved returns to the off state.

If the current through any of the low side IGBTs or free wheel diodes exceeds the current limit level

shown in table 6, a warning signal will be asserted on the CL output of the module. At the CL level, the

device is not in imminent danger of being damaged so the power devices are not disabled and normal

inverter operation will continue. The CL signal is a warning that is intended to be used by the system control

to either stop inverter operation or attempt output current regulation depending on the requirements of the

application. The current limit warning is derived from the analog current feedback signals described below.

The version 2 ASIPM has a built in temperature sensor that monitors the base plate temperature

of the module. If the temperature exceeds the OT level specified on the device data sheet, all six IGBTs are

turned off and a fault signal is asserted. The temperature sensor is particularly useful for detecting conditions

such as cooling fan failure, extreme ambient temperatures, improper mounting or heat sink problems.

Normal operation of the module will resume when the base plate cools below the over temperature resetlevel. The built in temperature sensor simplifies manufacturing by eliminating the need for mounting and

calibrating external heat sink temperature sensors.

In many high performance applications inverter output current sensors are required for system

control. In order to simplify the power stage design and eliminate the need for hall current sensors, the

version 2 ASIPM integrates three phase current sensing and provides analog feedback signals

proportional to the inverter output currents.

The feedback signals are generated by sampling the low side arm currents and processing them to

create an analog voltage proportional to the output phase currents. The process for deriving these signals is


11/15

illustrated in figure 24. The

current in the low side IGBT

and free wheel diode is

converted to a voltage

using the shunt RS. The

voltage across RS is then

amplified by amp 1 so that itswings 1.1V when theoutput current is at 200% of

the modules IO(RMS) rating.

The non inverting input of

amp 1 is supplied with a

2.25V reference that sets

the zero current output

voltage (VC0). The zero

current level is shifted up to

VC0so that the output signal

is always positive with

respect to logic common

and can be easilyconnected to the

microprocessor's analog

inputs. The output of AMP 1

is connected to a sample

and hold circuit that is

activated by a delayed low

side IGBT gate drive signal.

During the negative half

cycle the phase output

current is reconstructed

from the IGBT current

samples taken on every

high frequency PWM cycle. If gate drive signals are applied to the low side IGBT while its free wheel diode is

conducting the positive half cycle of the output phase current will also be reconstructed. The output of the

sample and hold circuit is buffered by AMP 2 to produce the analog current feedback signal VC. The

performance of the analog current feedback is

shown in figure 25. The version 2 ASIPM

provides analog current feedback signals for all

three output phases.

V

V

(U,V,W)

N

IC

V0

Delay

Chold

AMP 2

AMP 1RS

Gate Drive

VIN

VC

-

+

-

+

Vhold

IN

HOLD

IC

VC

off

on

Figure 24: Three phase

analog current feedback

VC(V)

1

0

3

4

5

2

0-100-200-300-400 100 200 300 400Load Current (%) Normalized to IORMS(rated)x 2

Current Feedback Signal Output Characteristic

Worst CaseError Band

150mV

Analog signal feedbackhold range

Conditions:VD=15V, TC= -20 ~ +100C

Figure 25: Three phase analog

current feedback performance

The version 2 ASIPM has 11

microprocessor compatible input and output

signals. All signals are referenced to the

common ground of the control power supply

allowing direct connection to a CPU. Table 7

summarizes the ASIPM's input and outputsignals. Figure 26 shows the recommended

interface circuit for the version 2 ASIPM. On

and off operations for all six IGBTs in the

ASIPM are controlled by the active low control

inputs. The fault signal and current limit warning

outputs are in an open collector configuration.

When a fault or current limit condition occurs

the respective output turns on and pulls the


12/15

CPU/DSP

ASIPM

5V 15V

5.1K5.1K

6

+ +

10K

0.1nF

VD


FO, CL

CU, CV, CW

GND

Figure 26: ASIPM Version 2

Interface Circuit Table 7: Version 2 ASIPM Control SignalsSignal Name Designation Description

Control Inputs UP, VP, WP,

UN, VN, WN

Inputs for controlling on/off

operation of the six IGBTs

in the IPM.

Fault Signal FO Fault status output signal

Current Limit CL Current limit warningsignal

Analog

Current

Feedback

CU, CW, CV Analog feedback for

output phase currents

signal line low.

D. ASIPM "Version 1" and 1200V For compact high

performance general purpose motor drives

The "Version 1" PS1101X and 1200V PS1201X ASIPMs are designed for compact high

performance general purpose industrial motor drives. These modules have basically the same three phaseanalog current feedback, level shifting, and boot strap supply schemes as the version 2 ASIPM. The main

difference is that shoot through interlock and p-side short

circuit protection are added, multi output fault signaling is

provided, and the power circuits are more complete. These

additional functions make the version 1 and 1200V

ASIPMs the most complex of all types currently available.

Figure 27: PS1101X

Version 1 ASIPM


Type Typical

Motor

Rating

(kW)

Inverter

Output

Current

(ARMS)

Peak Output

Current at

CL Warning

(AMPS)

Short Circuit

Protection

Level (SC)

(Amps)

PS11011 0.1 0.8 3.1 6.0

PS11012 0.2 1.5 5.8 12.0

PS11013 0.4 3.0 10.8 24.0

PS11014 0.75 5.0 17.3 43.0

PS11015 1.5 7.0 24.7 53.0

Figure 28: PS1201X 1200V ASIPM

Table 9: 1200V ASIPMs

Type TypicalMotor

Rating

(kW)

InverterOutput

Current

(ARMS)

Peak OutputCurrent at

CL Warning

(AMPS)

Short CircuitProtection

Level (SC)

(Amps)

PS12012 0.2 1.0 3.9 14.4

PS12013 0.4 1.6 5.8 14.4

PS12014 0.75 2.6 11.0 26.8

PS12015 1.5 4.0 15.6 38.0


13/15


14/15


15/15

levels. Hysteresis is built into the UV and OV trip logic in order to prevent oscillations.

The version 1 and 1200V ASIPMs have 14 microprocessor compatible input and output signals.

All signals are referenced to the 5V logic power supply allowing direct connection to a CPU. Table 10

summarizes the ASIPM's input and output signals. Figure 31 shows a typical external interface circuit.

VI. CONCLUSION

ASIPMs (Application Specific Intelligent Power Modules) consisting of a combination of power

devices, low voltage ASICs and high voltage ASICs are effective for simplifying and miniaturizing the power

section of small motor drives. Maximum system benefit is achieved when the package design and integrated

functions are optimized to meet the requirements of specific applications. This paper has outlined these

system considerations and presented a series of examples demonstrating the effectiveness of this

technology.

VII. REFERENCES

[1] G. Majumdar, et al. "A New Generation High Speed Low Loss IGBT Module", ISPSD, May 1992

[2] J Yamashita, et al. "A Study on the Short Circuit Destruction of IGBT's" , ISPSD, May 1993[3] G. Majumdar, et al. "A New Generation High Performance Intelligent Module" PCIM Europe May

1992

[4] Powerex "IGBTMOD and IntellimodTM

Application and Technical Data Book" Second Edition,

PUB#9DB-200, 1998

[5] E. Motto, et. al. "A New Generation of Intelligent Power Devices for Motor Drive Applications" IEEE

IAS Conference October 1993

[6] E. Motto "Protecting High Current IGBT Modules From Over Current and Short Circuits" HFPC

Conference May ,1995

[7] John Donlon, et. al. "A New Converter/Inverter System for Windpower Generation Utilizing a New

600 Amp, 1200 Volt Intelligent IGBT Power Module" IEEE IAS Conference October 1994

[8] E. Motto, et. al. A New Intelligent Power Module With Microprocessor Compatible Analog Current

Feedback, Control Input, and Status Output Signals, 1996 IEEE IAS Conference Proceedings

[9] Eric R. Motto A New Ultracompact ASIPM with integrated HVASIC 1997 Powersystems World

conference proceedings

[10] G. Majumdar et. al. Novel Intelligent Power Modules for Low-Power Inverters 1998 IEEE PESC

Proceedings

[11] S. Noda et. al. A Novel Super Compact Intelligent Power Module 1997 PCIM Europe conference

proceedings

application specific intelligent power modules -a novel approach to system integration in low power...

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