SV-PWM – Space vector PWM

The SV-PWM block generates PWM signals based on the Space Vector Modulation (SVM) algorithm. This algorithm determines the three vectors that are the closest to the reference vector and computes the dwell times for each one. Based on those times, a duty cycle is computed and a triangular carrier is used to generate the PWM signal for each phase.  The SVM method is explained in the Space Vector Modulation (TN145) and SVPWM vs SPWM modulation techniques (TN146) notes.

When using the single-rate update configuration, the computed duty cycles are synchronously applied at the end of the PWM period. With the double-rate update, the duty-cycle is updated twice per period: in the middle and at the end (in other words when the carrier reaches its maximum and when it reaches its minimum).

The frequency of the carriers is configured by connecting the SV-PWM block to a CLK – Clock generator. The frequency can even be tuned during the control execution as explain in Variable frequency operation with the B-Box/B-Board (PN121).

Like the other PWM blocks, the Space Vector Modulation block supports dead-time generation and can be activated or deactivated. More information is available on the PWM page.

Simulink SV-PWM block

Signal specification

• The input αβ0 is the normalized reference vector in the stationary reference frame (-1.15 to 1.15).
• The input signal > is the clock input and must be connected to the CONFIG block or to an independent CLK.
• The outputs are the generated PWM signals, according to the selected output mode and the converter type. The outputs are only used in the simulation.

Parameters

• Device ID selects which B-Box/B-Board to address when used in a multi-device configuration.
• Converter type configures the SV-PWM algorithm for a 2- or 3-level inverter.
• Output mode selects between a single PWM signal or complementary signals with a dead-time.
• Starting PWM channel: selects the first PWM output to be used for the set of PWM signals of the SV-PWM algorithm.
• Use optical outputs only selects if the PWM signals can be addressed only to the optical outputs, or if the electrical outputs (lanes 16 to 31) can also be used.
• Show ”activate” input makes the A signal input visible. If not checked, the SV-PWM block is active by default.
• PWM parameters update rate selects when the duty-cycle and phase parameters are applied.
  • Single-rate: they are applied at the end of the carrier period.
  • Double-rate: they are applied twice per carrier period: when the carrier reaches its lowest point and when it reaches its highest point.
• Dead-time duration: configures the dead-time duration if the Output mode is set at Dual (PWM_H + PWM_L).

PLECS SV-PWM block

Signal specification

• The input αβ0 is the normalized reference vector in the stationary reference frame (-1.15 to 1.15).
• The input A allows the activation (1) or deactivation (0) of the PWM output(s).
• The input signal > is the clock input and must be connected to the CONFIG block or to an independent CLK.
• The target outport (only visible at the atomic subsystem level) are the generated PWM signals, according to the selected Output mode (see PWM page for information). These outputs are only used in the simulation.

Parameters

• Device ID selects which B-Box/B-Board to address when used in a multi-device configuration.
• Converter type configures the SV-PWM algorithm for a 2- or 3-level inverter.
• Output mode selects between a single PWM signal or complementary signals with a dead-time.
• Starting PWM channel: selects the first PWM output to be used for the set of PWM signals of the SV-PWM algorithm.
• Use optical outputs only selects if the PWM signals can be addressed only to the optical outputs, or if the electrical outputs (lanes 16 to 31) can also be used.
• Show ”activate” input makes the A signal input visible. If not checked, the SV-PWM block is active by default.
• PWM parameters update rate selects when the duty-cycle and phase parameters are applied.
  • Single-rate: they are applied at the end of the carrier period.
  • Double-rate: they are applied twice per carrier period: when the carrier reaches its lowest point and when it reaches its highest point.
• Dead-time duration: configures the dead-time duration if the Output mode is set at Dual (PWM_H + PWM_L)

C++ functions

Specific to SV-PWM

void SvPwm_ConfigureOutputs(tSvModulator modulator, tPwmOutput startingOutput, tPwmOutputType outputType, unsigned int startingDevice);
Code language: C++ (cpp)

void SvPwm_ConfigureLevel(tSvModulator modulator, unsigned int level);
Code language: C++ (cpp)

void SvPwm_ConfigurePhase(tSvModulator modulator, float phase);
Code language: C++ (cpp)

void SvPwm_ConfigureClock(tSvModulator modulator, tClock clock);
Code language: C++ (cpp)

void SvPwm_RunCartesian(tSvModulator modulator, float dAlpha, float dBeta, float dZero);
Code language: C++ (cpp)

void SvPwm_RunPolar(tSvModulator modulator, float m, float phi, float dZero);
Code language: C++ (cpp)

void SvPwm_Run(tSvModulator modulator, float Vg, float Vh, float dZero);
Code language: C++ (cpp)

void SvPwm_ConfigureUpdateRate(tSvModulator modulator, tPwmRate rate);
Code language: C++ (cpp)

Functions common to all PWM drivers

These functions are common to all PWM blocks. Further documentation is available on the PWM page.

void SvPwm_ConfigureOutputMode(tSvModulator modulator, tPwmOutMode outMode, unsigned int device=0);
Code language: C++ (cpp)

void SvPwm_ConfigureDeadTime(tSvModulator modulator, float deadTime, unsigned int device=0);
Code language: C++ (cpp)

void SvPwm_Activate(tSvModulator modulator, unsigned int device=0);
Code language: C++ (cpp)

void SvPwm_Deactivate(tSvModulator modulator, unsigned int device=0);
Code language: C++ (cpp)