Renesas Electronics America Inc. © 2012 Renesas Electronics America Inc. All rights reserved. Sensorless Vector Control and Implementation: Why and How

© 2012 Renesas Electronics America Inc. All rights reserved.2 Renesas Technology & Solution Portfolio

© 2012 Renesas Electronics America Inc. All rights reserved.3 Microcontroller and Microprocessor Line-up Wide Format LCDs  Industrial & Automotive, 130nm  350µA/MHz, 1µA standby 44 DMIPS, True Low Power Embedded Security, ASSP 165 DMIPS, FPU, DSC 1200 DMIPS, Performance 1200 DMIPS, Superscalar 500 DMIPS, Low Power 165 DMIPS, FPU, DSC 25 DMIPS, Low Power 10 DMIPS, Capacitive Touch  Industrial & Automotive, 150nm  190µA/MHz, 0.3µA standby  Industrial, 90nm  242µA/MHz, 0.2µA standby  Automotive & Industrial, 90nm  600µA/MHz, 1.5µA standby  Automotive & Industrial, 65nm  600µA/MHz, 1.5µA standby  Automotive, 40nm  500µA/MHz, 35µA deep standby  Industrial, 40nm  242µA/MHz, 0.2µA standby  Industrial, 90nm  1mA/MHz, 100µA standby  Industrial & Automotive, 130nm  144µA/MHz, 0.2µA standby bit 8/16-bit

© 2012 Renesas Electronics America Inc. All rights reserved.4 Challenge: Sensorless vector control increases the energy efficiency of motor control systems that drive the smart society. However, understanding and implementing sensorless vector control is a herculean task. Solution: This class will help you understand key challenges associated with sensorless vector control and how to implement it using Renesas microcontrollers ‘Enabling The Smart Society’ MCU

© 2012 Renesas Electronics America Inc. All rights reserved.5 Agenda Need for vector control Theory behind vector control Challenges in implementing sensorless vector control RX62T MCU family for sensorless vector control Renesas motor control solutions

© 2012 Renesas Electronics America Inc. All rights reserved.6 Macro Factors Driving Need for Energy Efficiency Global Environmental Concerns Energy Efficiency Policies New Initiatives

© 2012 Renesas Electronics America Inc. All rights reserved.7 Realizing Energy Efficiency in Motor Control Industrial 44% Residential 26%Others 30% Energy Efficient Motors Electronic Control  Variable speed drives  Vector control  Direct torque control  Power factor correction  Motor Design  Motor Type Up to ~30% savings 15% 20% Motors (45%)

© 2012 Renesas Electronics America Inc. All rights reserved.8 Sensorless Vector Control Theory

© 2012 Renesas Electronics America Inc. All rights reserved.9 Permanent Magnet AC Motor Complex Control Sinusoidal stator current produces rotating field Rotor mounted magnetic field is rotating Maintain stator field orthogonal to rotor field X A A’ X B B’C’ X C ABC

© 2012 Renesas Electronics America Inc. All rights reserved.10 Vector Control Challenge Maintain orthogonality Error correction feedback loop – In-phase current = 0 – Orthogonal current set per torque requirements What parameters to adjust Voltage magnitude (PWM duty cycle) Need to transform current vectors to rotor frame Rotor Field Stator Field 90 0 ωrωr

© 2012 Renesas Electronics America Inc. All rights reserved.11 Reference Frame Transformation Vector control advantages Maximizing torque (efficiency) Independent control of flux and torque Snappy torque control for load variation Mapping 2-phase Rotor Frame Three-phase Stator u i w i v i 0 120

© 2012 Renesas Electronics America Inc. All rights reserved.12 Current Transformation to 2-ph Rotor Frame Step 1 : 3-ph to 2-ph conversion u i w i v i F Clarke Transformation  uvw stationary frame  i  i F  αβ stationary frame d I q I F q- axis d- Park Transformation  dq rotatory frame Step 2 : 2-ph stationary frame to 2-ph rotor frame (rotating) Rotor position ( θ ) needed

© 2012 Renesas Electronics America Inc. All rights reserved.13 Sensorless Vector Control Lower cost but more complex implementation Current and motor parameters to estimate rotor position Increased reliability Reduced cost of sensor ($3-$20) Less physical space needed Need to estimate θ without sensors Speed /position sensor Speed Calculation Motor PWM Generation PI Controller PI Controller ω*ω* ω i*i* i θ Position Estimation i

© 2012 Renesas Electronics America Inc. All rights reserved.14 is the rotor flux linked is the rotor position Flux LinkageVoltage Equation =0 Motor Model in  Frame Potential Inaccuracy: If full load or large motor

© 2012 Renesas Electronics America Inc. All rights reserved.15 Rotor Position and Speed Estimation Bottleneck: arctan implementation takes several CPU cycles

© 2012 Renesas Electronics America Inc. All rights reserved.16 Renesas Flux Observer Model Potential inaccuracy: Noise in measuring current and voltage Potential inaccuracy: Effect of temperature on resistance

© 2012 Renesas Electronics America Inc. All rights reserved.17 Low pass filter ynyn Derivative dndn Low pass filter Cascaded low pass filters rather than direct integration First low pass filter Derivative Second low pass filter Negate the effect of DC offset in measured current/voltage Flux Observer Implementation

© 2012 Renesas Electronics America Inc. All rights reserved.18 Sensorless Vector Control Loop abc to αβ abc to αβ iaia ibib dq To αβ dq To αβ vαvα vβvβ to abc αβ to abc Speed Estimation θ ωrωr ω*rω*r id Regulator i d *=0 idid iqiq iq Regulator Speed Regulator I q* 3-ph Inverter 3-ph Inverter 6 Sine PWM DC BUS αβ to dq αβ to dq iαiα iβiβ θ Flux and Position Observer ClarkePark Park -1 Clarke -1

© 2012 Renesas Electronics America Inc. All rights reserved.19 Implementation Challenges

© 2012 Renesas Electronics America Inc. All rights reserved.20 High performance CPU, FPU Implementation Challenges 1. Computation intensive routines 12Bit Simultaneous Sampling ADC 2. Multiple current/voltage measurement Noise immunity, PWM shut off 3. Robust performance On-chip analog, data flash, dual motor 4. Cost effective design Requirements MCU Considerations

© 2012 Renesas Electronics America Inc. All rights reserved Computation Intensive High-performance RX600 Core 100MHz CPU 1-cycle flash access 32x32 H/W multiplier 32/32 H/W divider 32bit Barrel Shifter Floating point unit Clarke/Park Transformations Flux Estimation Rotor position and speed

© 2012 Renesas Electronics America Inc. All rights reserved.22 Floating Point Unit Advantages Performance Wide range and high resolution No scaling, overflow or saturation Reduced code size Ease of Use Ease of coding, reading, debugging Compatible with the C/Matlab simulation code

© 2012 Renesas Electronics America Inc. All rights reserved.23 Floating Point : Range and Resolution Range Resolution Fixed Point Q11.21 Single Precision Floating Point Range Resolution ∫ or ∑

© 2012 Renesas Electronics America Inc. All rights reserved.24 Fixed-point Calculations Requires Scaling X(n) = X(n-1) + A1 * E(n) (16b, Q12.4)(16b, Q8.8)(32b,Q14.18) (32b,Q20.12) (32b,Q14.18) MULT SHIFT (32b,Q14.18)

© 2012 Renesas Electronics America Inc. All rights reserved.25 No Scaling Needed FPU ImplementationFixed-Point Implementation SHIFT

© 2012 Renesas Electronics America Inc. All rights reserved.26 No Saturation Check Fixed-Point Implementation Check for Saturation

© 2012 Renesas Electronics America Inc. All rights reserved.27 Reduced Code Size FPU ImplementationFixed-Point Implementation FPU instructions make code and the execution time smaller

© 2012 Renesas Electronics America Inc. All rights reserved.28 Readability Fixed-Point ImplementationFPU Implementation Parameters Park Transformation Code

© 2012 Renesas Electronics America Inc. All rights reserved.29 FPU Brings Ease of Simulation Portable to FPU Bidirectional Time-consuming Unidirectional Simulation Platform Inherently floating point Floating Point Algorithm Fixed Point CPU Fixed Point Algorithm Floating Point CPU

© 2012 Renesas Electronics America Inc. All rights reserved.30 FPU Implementations No Load/Store Instructions Renesas RX FPU Floating- Point Unit Dedicated Data Registers General Registers Traditional FPU Load/Store General Registers Floating- Point Unit

© 2012 Renesas Electronics America Inc. All rights reserved Accurate Analog Signal Measurement Simultaneous sampling ADC Oversampling current waveform Filtering to mitigate noise Dual registers for 1-shunt UVWUVW 50us 5us 4 ADC Samples Estimates based on current and voltage Integration for flux estimation Multiple simultaneous measurements

© 2012 Renesas Electronics America Inc. All rights reserved.32 Current Measurement Techniques 3-shunt UVWUVW IWIW I W +I V 1-Shunt Advantages Cost reduction (Res, PGA) No need for 3-ph calibration Reliability 1-shunt Challenges ADC samples twice quickly Reconstruction of current 1-shunt I W,V,U

© 2012 Renesas Electronics America Inc. All rights reserved.33 Support for 3-shunt and 1-shunt Detection AN0 AN1 AN2 Multiplexer ADC Set 1 A/D Register 2 Register CH1 Register CH2 Register CH3 ch0 PGA S/H External Reference 3 S/H for 3 shunt current detection AN03/CVref L Register 1 Double register for 1-shunt 12-bit ADCs with 1us conversion time Double register for 2 samples 3S/H for one-shot sampling of three phase currents Self-diagnostic capability for UL/IEC safety requirements PGA Window Comparators CPU Interrupt PWM Shut off (POE)

© 2012 Renesas Electronics America Inc. All rights reserved Robust Performance Noise immune MCU design Careful power/ground layout Pin noise filtering 5V option On-chip hardware POE circuit Fast window comparators Susceptibility to noise Hardware shut off

© 2012 Renesas Electronics America Inc. All rights reserved Cost Effectiveness Complete solution for driving two 3-ph motors 6 programmable gain amplifiers 6 window comparators 2 x 3ph cPWM timers 2 x quadrature encoder inputs Data flash Scalability RX6xT – package, ROM RX200 - performance On-chip integration Scalability pins KB 63TL 62T 63TH Scalability

© 2012 Renesas Electronics America Inc. All rights reserved.36 Implementing Sensorless Vector Control Using RX62T

© 2012 Renesas Electronics America Inc. All rights reserved.37 RX62T Motor Timer Set (MTU3) 100MHz, 16bit Timers Protection Features PWM shut down (Ext, Comparator, Clock) Mode registers inaccessible during operation ch0 ch1 ch2 ch3 ch4 ch5 MTU3 3-phase cPWM O/P U,V,W ch6 ch7 3 Input Captures 3-phase cPWM O/P U,V,W Quadrature Encoder1 A,B,Z Quadrature Encoder2 A,B,Z

© 2012 Renesas Electronics America Inc. All rights reserved.38 Hardware Implementation Motor Current 6 PWM Generation PWM Shut Off PGA S/H 12-bit ADC Analog Unit 0 RX62T RX600 CORE x3 Comparator 3 3-phase inverter Gate Driver MTU CH3/4 3 3-phase BLDC Motor

© 2012 Renesas Electronics America Inc. All rights reserved.39 Software Implementation Initialization PWM Interrupt Current Reconstruction Speed PI Last ω & Reference ω V(u,v,w) -> PWM Duty New θ Estimation New Speed Estimation Current PI Voltage (d,q) V BUS /Current Measurement (u,v,w) -> (α,β) ->(d,q) Last θ Reference Current Actual Current (d,q) -> (α,β) (u,v,w) <- Last θ

© 2012 Renesas Electronics America Inc. All rights reserved.40 Fixed point vs. FPU Comparison Algorithm: Sensor less Vector Control with 1-Shunt Current Detection PWM Carrier Frequency: 20kHz Current Loop: 10kHz Renesas Inverter Board RX62T Starter Kit

© 2012 Renesas Electronics America Inc. All rights reserved.41 CPU Bandwidth Usage CPU BW

© 2012 Renesas Electronics America Inc. All rights reserved.42 CPU Bandwidth Usage us Floating-point code 40% faster

© 2012 Renesas Electronics America Inc. All rights reserved.43 Code Size Floating-point code size is 45% lower B

© 2012 Renesas Electronics America Inc. All rights reserved.44 Driving Two 3-Phase BLDC Motors RX600 Motor KitExternal Inverter Motor #2 Motor #1 Sensorless Vector Control Floating point math CPU BW used <50%

© 2012 Renesas Electronics America Inc. All rights reserved.45 Implementation for Two Motor Control Control Loop 1 Control Loop 2 CPU Available MTU.CH3/4 10KHz MTU.CH6/7 10KHz Software Implementation Control loop executed at Timer underflow interrupt Both interrupts at same priority level Alternate Implementations Control loops at different rates Interrupt at overflow/underflow MTU.CH3/4 10KHz MTU.CH6/7 20KHz Control Loop 2 Control Loop 1

© 2012 Renesas Electronics America Inc. All rights reserved.46 Software Implementation Initialization PWM Interrupt Current Reconstruction Speed PI Last ω & Reference ω V(u,v,w) -> PWM Duty New θ Estimation New Speed Estimation Current PI Voltage (d,q) V BUS /Current Measurement (u,v,w) -> (α,β) ->(d,q) Last θ Reference Current Actual Current (d,q) -> (α,β) (u,v,w) <- Last θ PWM Interrupt2

© 2012 Renesas Electronics America Inc. All rights reserved.47 Performance Comparison with a High-end DSP RX62T offers tremendous value Comparable performance Significantly lower cost 16us 18us +50% 7.8KB 7.4KB

© 2012 Renesas Electronics America Inc. All rights reserved.48 Response to Step Change in Load High-end DSP RX62T

© 2012 Renesas Electronics America Inc. All rights reserved.49 Renesas Motor Control Solutions

© 2012 Renesas Electronics America Inc. All rights reserved.50 Motor Control MCUs RX600 Family -Dual motor vector control -Floating point -RX600 Motor Kit RX62T 100 MHz, 165DMIPs 64KB – 256KB RX62T 100 MHz, 165DMIPs 64KB – 256KB RX MHz,50DMIPs 32KB-256KB RX MHz,50DMIPs 32KB-256KB RX200 Family -Single motor vector control -Entry level RX core Timeline Performance RL78/G14 32 MHz, 44DMIPs 32KB – 256KB RL78/G14 32 MHz, 44DMIPs 32KB – 256KB RL78/G14 -Scalar control (low-end vector control) -RL78 Motor Kit RX Core RX63TL 100 MHz, 165DMIPs 32KB – 64KB RX63TL 100 MHz, 165DMIPs 32KB – 64KB RX63TH 100 MHz, 165DMIPs 256KB – 512KB RX63TH 100 MHz, 165DMIPs 256KB – 512KB R8C/3xM 20 MHz 8KB – 128KB R8C/3xM 20 MHz 8KB – 128KB Oct V

© 2012 Renesas Electronics America Inc. All rights reserved.51 Evaluation Kits for Vector Control Extensive Code Support Flexibility to Evaluate and Develop GUI External Inverter Connector RX600 Motor Kit RL78 Motor Kit

© 2012 Renesas Electronics America Inc. All rights reserved.52 High Voltage Demo Platform (2KW) IGBTs RJH60D5DPQ-A0 Interleaved PFC AC to DC rectifier Line AC V CPU Board Gate Driver PWM Hall and Encoder Current Sense In-circuit Scope LCD Potentiometer and Push Buttons Set RPM RPM Is Iq Vdc Set RPM RPM Is Iq Vdc

© 2012 Renesas Electronics America Inc. All rights reserved.53 2KW Inverter Platform

© 2012 Renesas Electronics America Inc. All rights reserved.54 Summary Sensorless vector control improves the motor system efficiency Implementing sensorless vector control requires careful selection of MCU Renesas provides several motor control MCUs depending on the application requirements RX600 and RL78 motor control kits are available for an easy evaluation of Renesas solutions High voltage platforms are also available

© 2012 Renesas Electronics America Inc. All rights reserved.55 Questions? Questions?

© 2012 Renesas Electronics America Inc. All rights reserved.56 Challenge: Sensorless vector control increases the energy efficiency of motor control systems that drive the smart society. However, understanding and implementing sensorless vector control is a herculean task We discussed key challenges associated with sensorless vector control and how to implement it using Renesas microcontrollers Do you agree that we accomplished the above statement? ‘Enabling The Smart Society’ MCU

Renesas Electronics America Inc. © 2012 Renesas Electronics America Inc. All rights reserved.