Transcript Motor Control Solutions - Renesas e-Learning

RX62T&N Floating Point Unit (FPU)
Motor Control Solution
FPU Sensorless Vector Control on RX
Renesas Electronics America Inc.
Takechi Kenji; Huangsheng Xu
Consumer & Industry BU
June 17, 2010
FAE Training
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Overview: Motor Control Solutions
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Motor Control Solutions
HW Platform
Algorithm
1-Ø ACIM
(PSC)
V/F, Open Loop
Y
Fixed Duty
Y
Customer
Closed Loop (Hall)
Y
Customer
1. TRIAC Control ( speed loop w/Tachometer)
Y
TRIAC Board
2. DC Chopper (speed loop w/Tachometer)
Y
DC Chopper Board/Shakti II
(High Voltage)
3. V/F Scalar Control, Open Loop
Y
Y
MCRP25/Shakti II
V/F Scalar Speed Loop w/Tachometer
Y
Y
Shakti-II (Low/High
Voltage)
Y
Shakti-II (Low/High
Voltage)
1-Ø BLDC
Universal
(Brushed
DC) Motor
3-Ø ACIM
R8C
RX62
T/N
SH2/
Motor
Type
Shakti-II (High Voltage)
Sensorless Vector Control
4. 120-deg Trapezoidal (Hall)
Y
MCRP25, Shakti-II
5. 120-deg Trapezoidal (BEMF)
Y
MCRP25, Shakti-II
6. 180-deg Sinusoidal Control (HALL)
Y
MCRP25, Shakti-II
7. Sensor based Vector Control
8,9. Sensorless Vector Control, 2 DCCT, 3shunt, 1-shunt
3-Ø BLDC
3
SH2A
10. Position Control (Encoder + Hall)
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Y
(FPU)
Y
Shakti-II (Low/High
Voltage)
Y
Shakti-II (Low/High
Voltage)
Y
Shakti-II (Low/High
Voltage)
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Shakti II Reference Design Power Platform
Motor connector
Rectifier
Shunt resistor
LV power supply
Current sensors
IPM
AC power input
Hall/Encoder input
RSK connectors
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RSKs – R8C, SH7124, SH7137, SH7086,
SH7286 and RX62T
R8C
SH7086
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SH7124
SH7137
SH7286
RX62T
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Features of Shakti II Reference Design
Power Platform
 110 or 220VAC input, and 0-220VAC output
 12-75V DC, or 160/320V DC bus voltage
 Various power modules @ 10A, 16A and 20A modules
 Speed sensor inputs of hall sensor, encoder, and tachometer
 Three high side phase current measurements via LEMs and
one shunt current measurement using precision resistor and
special timers;
 Various RSKs of R8C, M16C, SH2/2A and RX62T/N series can
directly plug in
 Support multiple PWM modes including Complementary pairs
with automatic Dead-time insertion
 Drive Universal Motor, Brushed DC, BLDC, PMSM Motor and
Induction Motor
6
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RX62T/N FPU Based
Sensorless Vector Control of PMSM Motor
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Floating Point Unit (FPU) Advantages
 More robust
 No scaling and saturation
 Ease of use
 Performance boost
 Improve calculation accuracy
 Increase the code execution speed
 Reduce the CPU bandwidth usage
 Reduce the code size
 C-code compiler friendly
 Compatible with the C/Matlab simulation code
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Fixed Point Development Dilemma
Simulation
Platform
(i.e. C, Matlab)
Take time to convert the
code to fixed point
(one way)
Fixed Point Algorithm
(C or C++)
Floating Point
Algorithm (C or C++)
Fixed Point Unit
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Motor control development
usually starts with simulation
in Floating Point
Can be easily ported to
floating point device
(bi-direction)
Floating Point Unit
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IEEE 754 Floating Point Format
IEEE 754 Floating Point Format
e
m
Fractional Representation
e
If S=0, Value=(1.m)* 2
e
If S=1, Value=-(1.m)* 2
0<m<1
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For example:
1
3.1415926=1.5707963* 2
e=1; m=0.5707963.
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RX-FPU Benchmarks
Single precision operations are 1.5 times or more faster using FPU
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RX600 without FPU
Comparison
Single
precision
RX600 with FPU
(Number of Cycle)
(Number of Cycle)
(No FPU/RX-FPU)
Sinf
Cosf
Tanf
Asinf
Acosf
Atanf
Logf
Expf
Powf
236
246
556
1,330
1,683
230
249
223
5,018
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118
185
186
197
154
168
138
619
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1.9
2.1
3.0
7.2
8.5
1.5
1.5
1.6
8.1
Renesas Sensorless Vector Control Strategy
 r*
Commanded speed *
iq
r
Speed Regulator
r
Observed
actual
speed
id  0
*
id
iq
Inverse
Inverse
park transform
Clarke transform
*
Uq
*
iq PI
U
d,q
, 
Regulator
to
id PI
Regulator
Ud
*
, 
T 1 ( )
U
to
a, b, c
*
DC Bus
PWM1~6
Voltage
Source
3-phase
Inverter
SIN
PWM
Current loop

Motor Model
Based Flux and
Position Observer
Clarke transform
iq
to
d,q
id
Park transform
ia
, 
i
T ( )
r
a,b,c
to
i
, 

Speed Estimation
Speed loop
ib
3-phase
PMSM
FPU makes vector control transformation, position and speed
observer implementation easier and more accurate.
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FPU Implementation Software Modules
Sensorless Vector Control Algorithm
(Flux observer, speed estimation, PI controller, protection, space vector PWM modulation ...)
Initialization
Startup
Procedure
Parameter
Definitions
Current id
Regulator
PWM
Duty Calculation
WDT
IWDT
LVD
Speed Setting &
Ramp Control
Current iq
Regulator
Space Vector PWM
Generation
POE
2xADC
ADC
Sampling
Vector Control
Transformation
Flux & Position
Observer
Speed
Estimation
Protections
(locked rotor, lost control, overcurrent, POE, watchdog …)
12xMTU 512KFlash
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Speed
Regulator
SCI
Communication
96KRAM SCI/CAN/Ethenet
RX62T&N
100MHz 32bit FPU
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PI controller
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Taking Advantages of FPU Implementation
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Motor Phase Current Measurement
Fixed-Point Implementation
FPU Implementation
FPU uses the actual current values without scaling and bit shift
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Current Measurement by Assembly Code
Fixed-Point Implementation
FPU Implementation
Renesas Complier uses the FPU instructions and optimizes
the FPU code to make the FPU Assembly code and the
execution time much smaller.
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α, β to d&q Transformation
Fixed-Point Implementation
FPU Implementation
FPU makes the vector control transformation just like directly writing
the equations.
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Flux Observer
Fixed-Point Implementation
FPU Implementation
For FPU, no saturation and limits, and easily implemented.
18
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Motor Parameter Definitions
Fixed-Point Implementation
FPU Implementation
FPU uses the real values without any scaling and calculations.
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FPU Sensorless Vector Control Testing
Results and Performance Comparison
between FPU and Fixed-Point
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RX62T Testing Setup
RX62T RSK
Renesas Power Board
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RX62N Testing Setup
RX62N Eva-Board
Renesas Power Board
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Speed Profile (Actual Speed vs. Ref. Speed)
from 12krpm to 30krpm at 20kHz PWM Frequency
<250ms
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<500ms
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Current Acceleration and Deceleration
during One Cycle from 12 to 30krpm at 20KHz PWM
<200ms
<250ms
250ms rising time
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250ms falling time
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Motor Phase Currents
at 12krpm and30krpm with 20kHz PWM Frequency
12krpm (2A/div)
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30krpm (2A/div)
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CPU Bandwidth
at 10KHz and 20kHz PWM Frequency
10kHz (23%)
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20kHz (46%)
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CPU Bandwidth and Code Size Comparison
at 10KHz PWM Frequency
CPU Bandwidth
Fixed-Point SVC
FPU SVC
Sine, Cosine, Atan functions
38%
23%
Sine, Cosine, Atan tables
26%
18%
Code Size
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Fixed-Point SVC
FPU SVC
Sine, Cosine, Atan functions
14.273K
7.222K
Sine, Cosine, Atan tables
12.462K
6.221K
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Conclusions
 RX FPU sensorless vector control was developed and implemented to run the
motor as required from 12krpm to 30krpm at 20kHz PWM Frequency.
 The FPU makes sensorless vector control easy to implement, modify, debug,
and maintain, and re-use. It removes scaling and saturation issues. The final
code is the same as the simulation code.
 The FPU improves the position and speed estimation accuracy to make the
sensorless vector control more accurate, which further improves the control
performance - current harmonics, speed vibration, and noise.
 The FPU reduces the CPU bandwidth usage. In comparison with the fixed-point
SVC, the FPU SVC CPU bandwidth usage is reduced more than 20%, from 26%
to 18%. If math functions are directly calculated, the FPU CPU bandwidth usage
is reduced more than 40%, from 38% to 23%.
 The FPU code size is only half of the fixed-point code size. This increases the
chance to use a smaller Flash size on the MPU, lowering cost.
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Summary of Renesas FPU Motor Control Solution
 Complete Solutions – Hardware and Software, which are
easily and rapidly prototyped to meet customers’
requirements and save development time to products.
 Open Technologies - full disclosure of core motor control
algorithms, low-end drivers, system functions, source
codes, schematic and layout.
 Full Technical Supports – technical documents,
development tools, application notes, application software,
MCU update information.
Renesas FPU makes “Motor Control” much easier
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Renesas Electronics America Inc.
© 2010 Renesas Electronics America Inc. All rights reserved.