solar power generation systems 28-02-2016
TRANSCRIPT
1
Charge Controllers & Smart Energy Monitoring Systems
• Charge Controller Features , Types and Applications
• Smart Energy metering
Reddyprasad, AP, SVCE,Bengaluru.
2
How solar works ? ( Grid Connected system )
3
Charge Controllers ( Off-Grid System )
Manage Energy Flow between : Solar Panel - > Battery
Battery - > Load
Battery charging Methods
4
• Constant Voltage Cheap battery chargers
• Constant Current Switches off at voltage set-point
• Taper Current Unregulated constant voltage
• Pulsed charge Voltage PWM, on/rest/on
• Negative Pulse Charge Short discharge pulse
• IUI Charging Constant I, constant V, equalize
• IUO Charging Constant I, constant V, float
• Trickle charge Compensate for self discharge
• Float charge Constant voltage below gassing V
• Random charging Direct Solar Panel
Factors that decide Life of a Battery
5
• Incorrect charge voltage.
• Too low a voltage >> Less % of charging >> sulphating >> loss of Capacity
• Excessive voltage >> causes excessive gas >> to water loss and drying out.
• Excessive discharging >> Early failure / Shorter Life
• Too many cycles >> Shorter Life
• Charging without 3 step regulation and very high electrolyte
temperatures.
6
Battery Charging - Graphically
Single-stage battery charging is simpler to manage, but
multistage battery charging brings battery to a higher state
of charge.
Multistage battery charging needs intelligent controllers.
Why Charge Controllers ?
7
• Prevents battery overcharge
• Blocks reverse current
• Prevent over-discharge from batteries (some models)
• Prevent electrical overload (some models)
• Displays battery status
8
Overcharge Protection
9
Overdischarge Protection
10
Charge Controller Status
Some charge controllers include displays or LEDs to
indicate battery voltage, state of charge, and/or
presenting operating mode.
Types of Charge Controllers
• Shunt type charge controller
• Series type charge controllers
• PWM type
• MPPT type
• Diversionary
&
• Hybrid charge controller
11
12
Shunt Charge Controllers
Shunt charge controllers control charging current by short-circuiting the array.
13
Series Charge Controllers
Series charge controllers control charging current by opening
the circuit from the array.
14
Pulse-Width Modulation
Pulse-width modulation (PWM) simulates a lower current level by pulsing a higher current level ON and OFF for short intervals.
15
Maximum Power Point Tracking
Maximum power point
tracking manipulates
the load or output
voltage of an array in
order to maintain
operation at or near the
maximum power point
under changing
temperature and
irradiance conditions.
16
MPPT – How it works ?
17
Diversionary Charge Controller
A diversionary charge controller regulates charging current by diverting excess power to an auxiliary load when the battery is fully charged.
18
Hybrid Charge Controller
Charge controllers
designed for hybrid
PV systems must
manage multiple
current source
simultaneously.
Importance of Various Set Points
• Charge regulation set points
• Voltage regulation set points
• Load control set points
Temperature compensation ??
19
20
Charge Regulation Setpoints
Charge regulation setpoints are the voltage levels at which the charge controller interrupts or limits the charging current from the array to the battery bank.
21
Voltage Regulation Setpoints
The optimal voltage regulation setpoints depends
on the type of battery and charge controller.
22
Load Control Setpoints
Load control setpoints
are the voltage levels
at which the charge
controller interrupts or
limits the discharging
current from the battery
bank to the loads.
23
Setpoint Adjustments
Setpoints are adjusted
with controls inside the
charge controller.
24
Battery Temperature Sensors
Temperature probes are
placed between batteries
and connect to a charge
controller to compensate
for the charge regulation
setpoint.
25
Charge Controller Selection Criteria
Many criteria should be considered when selecting charge controllers for PV systems.
26
Multiple Arrays
Larger PV system often
use independent charge
controllers for each
array source circuit.
27
Battery Banks With Charge Controllers
Separate charge
controllers are usually
recommended for
charging independent
battery banks.
28
Battery Banks With One Charge Controller
In some cases, a single charge controller may
be used to charge independent battery banks.
Do I need Charge controller for
every Solar Application ?
29
30
Self-Regulating PV Systems
To balance a charge to
and from the battery in a
self-regulating PV system,
the load must be well
defined, the battery must
be oversized, and the
array current must be self-
limiting.
Smart Energy Metering
31
Net metering
32
Smart APPs – Cloud powered
33
Q & A
Thank you
34