3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Digital Regulation by Emulating Analogue Controllers: Implementation
•The sound of power supplies
•Self-learning Regulation
Niels HeidbrookDESY
•Elimimate Supply voltage influence: Prefilter design
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
AC load
Power supply
Iload
filter
C
LSCR bridge
12 pulseUSCR
f0=600Hz
ISCR ~ constant
U1
U2
U3
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Power supply
Iload
C
L
delay
U=4Vpp
f0=600Hz~
(Iload Delta-Sigma ADC delay = 1ms)
AC load
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
filter
C
L
U=4Vpp
f0=600Hz
delay
~reaction ~
Iload
AC load
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Iload
filter
C
L
U=4Vpp
f0=600Hz
pre-delay
~pre-action ~U=4Vpp
f0=600Hz
action
AC load
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Iload
U=4Vpp
f0=600Hz~ ~
U=4Vpp
f0=600Hz
Power supply =
Frequency generator
600Hz @ 4Vpp => High internal filter current
AC load
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Self-learning Regulation
Power supply
Uload=D*UsupplyDUload
RegulatorDuty cycle D0
Usupply
Frequency generator
(Ram Curve)50Hz Mains triggerOnly hardware:
Iload
Iload
Iload = constant?change
D0
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Self-learning RegulationIload
USCR
f0=600Hz~ ~
Uout
f0=600HzPower supply =
Frequency generator
t
Uout
~
Ram curve
delay
Ram curve
Average Iload
Iload
pre-delay
50Hz Mains trigger
Only hardware:
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Self-learning RegulationIload
USCR
f0=600Hz~ ~
Uout
f0=600HzPower supply =
Frequency generator
t
Uout
~
Ram curve
delay
Ram curve
Average Iload
Iload
pre-delay
50Hz Mains trigger
Only hardware:
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Self-learning RegulationIload
USCR
f0=600Hz~ ~
Uout
f0=600HzPower supply =
Frequency generator
t
Uout
~
Ram curve
delay
Ram curve
Average Iload
Iload
pre-delay
50Hz Mains trigger
Only hardware:
Instability at wrong learning delay
Too long Too short
Linear approximation between the points
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Self-learning Regulation
t
Uout
Ram curve
Average Iload
pre-delay
50Hz Mains trigger
Only hardware:
Instability at wrong learning delay
Solution 1:
Take less resolution of the Ram curve
Iload
Inaccurate at high frequencies
Linear approximation between the points
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Self-learning Regulation
t
Uout
Ram curve
Average Iload
pre-delay
50Hz Mains trigger
Only hardware:
Instability at wrong learning delay
Too long Too short
Mix in 1st derivation of Ram curve
Iload + K*d/dt(Ram curve)= constant
Iload is not constant
Solution 2:
Mix in 1st derivation of Ram curve
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Mains
=
~
Power supply
Rectifier
Load
Disturbance
Test circuit
Self-learning Regulation
Iload
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Power supply
Uload=D*UsupplyDUload
Regulator
Duty cycle D
Usupply
Elimimate Supply voltage influence:
Prefilter design
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Elimimate Supply voltage influence:
Prefilter design
Power supply
Uload=D1*UsupplyDPrefilter
D1=D/UsupplyUload
Regulator
Duty cycle D D1
Usupply
Prefilter
Uload=D1*Usupply
Uload=(D/Usupply)*Usupply
Uload=D
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
The sound of power supplies
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
The sound of power supplies
1. Unique WAV file Header
‘RIFF’
Size
(don’t care) ‘WAVE’ ‘fmt ’ Always: LSB is first
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
The sound of power supplies1. Unique WAV file Header
Chunk size
(don’t care) Format code
Number of interleaved channels=1Sampling
Rate
22050Bit/s
Data Rate
44100Bit/s
Data block size
(don’t care)
Bits per sample=16
Speaker position mask
(don’t care)
First 16 bit data value
Size of extension
(don’t care)
Number of valid bits
(don’t care)
Hex:2078
Dez:8312
(complement on two)
=>invert MSB bit
Dez:8312=>
ADC value was 41080
Always: LSB is first
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
The sound of power supplies2. Append test data (Saw tooth signal)
LSB
byte is always the same
(example)
MSB
byte counts downwards
2. Append ADC data in
2’s complement.
(inverted MSB bit)
Append LSB first.
1. Take the Header
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
The sound of power supplies3. Wave analysis Audacity (freeware)
Mono, 22050 bit/s
WaveSawToothExample.wav
The data has to be long enough to be played in Winamp.
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
The sound of power supplies4. Frequency analysis Audacity (freeware)1351Hz
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012
Java applet for continuous wave analysis
Digital regulation is needless
Have fun listening to your power supplies
Conclusion
3rd Workshop on Power Converters for Particle Accelerators (POCPA)
2012