PWM Reference Generator

Generate modulation signals, duty cycles, and phase voltages from reference voltages based on modulation method

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Libraries:
Motor Control Blockset / Controls / Math Transforms
Motor Control Blockset HDL Support / Controls / Math Transforms

Description

The PWM Reference Generator block generates modulation signals, duty cycles, and phase voltages from reference voltages based on selected modulation method. The block provides an option to limit its output which can be used to achieve simplified overmodulation or prevent erratic switching behavior.

The block accepts either the phase voltages (V_abc) or the stator reference voltages (V_αβ) described by the α-β voltage components.

The block supports both the SI unit and per-unit (PU) systems (see Per-Unit System for more details).

Use this block to perform sinusoidal PWM (SPWM) and space vector modulation (SVM) along with these discrete pulse-width modulation (DPWM) methods that reduce switching losses:

• 60 DPWM — 60 degree discontinuous PWM

• 60 DPWM (+30 degree shift) — +30 degree shift from 60 DPWM

• 60 DPWM (-30 degree shift) — -30 degree shift from 60 DPWM

• 30 DPWM — 30 degree discontinuous PWM

• 120 DPWM — Positive DC component

• 120 DPWM — Negative DC component

For discontinuous PWM (DPWM), the block clamps the modulation wave to the positive or negative DC rail for a total of 120 degrees during each fundamental period per phase. During each clamping interval, the modulation discontinues.

The figure shows the sinusoidal PWM (SPWM) waveform.

The figure shows the space vector modulation (SVM) waveform.

The figure shows a 60-degree DPWM waveform with two 60-degree clamped intervals per fundamental period.

The figure shows a 60-degree DPWM waveform with a positive 30-degree phase shift.

The figure shows a 60-degree DPWM waveform with a negative 30-degree phase shift.

The figure shows a 30-degree DPWM waveform with four 30-degree clamped intervals per fundamental period.

The figure shows a 120-degree DPWM waveform with positive DC clamping.

The figure shows a 120-degree DPWM waveform with negative DC clamping.

Examples

Field-Oriented Control of Induction Motor Using Speed Sensor

Implements the field-oriented control (FOC) technique to control the speed of a three-phase AC induction motor (ACIM). The FOC algorithm requires rotor speed feedback, which is obtained in this example by using a quadrature encoder sensor. For details about FOC, see Field-Oriented Control.

• Open Model

Field-Oriented Control of PMSM Using Hall Sensor

Implements the field-oriented control (FOC) technique to control the speed of a three-phase permanent magnet synchronous motor (PMSM). The FOC algorithm requires rotor position feedback, which is obtained by a Hall sensor. For details about FOC, see Field-Oriented Control.

• Open Model

Ports

Input

V_α — α-axis stator reference voltage component

scalar

Stator reference voltage component along α-axis of the αβ reference frame.

Dependencies

To enable this port, set Input type to Valphabeta and select the Expand voltage input parameter..

Data Types: single | double | fixed point

V_β — β-axis stator reference voltage component

scalar

Stator reference voltage component along β-axis of the αβ reference frame.

Dependencies

To enable this port, set Input type to Valphabeta and select the Expand voltage input parameter..

Data Types: single | double | fixed point

V_αβ — Single vector signal for αβ stator reference voltage

scalar

Single vector signal for αβ stator reference voltage.

Dependencies

To enable this port, set Voltage input type to Valphabeta and clear the Expand voltage input parameter.

Data Types: single | double | fixed point

Va — Phase component

scalar

Component of the three-phase system in the abc reference frame.

Dependencies

To enable this port, set Input type to Vabc and select the Expand voltage input parameter..

Data Types: single | double | fixed point

Vb — Phase component

scalar

Component of the three-phase system in the abc reference frame.

Dependencies

To enable this port, set Input type to Vabc and select the Expand voltage input parameter..

Data Types: single | double | fixed point

Vc — Phase component

scalar

Component of the three-phase system in the abc reference frame.

Dependencies

To enable this port, set Input type to Vabc and select the Expand voltage input parameter..

Data Types: single | double | fixed point

V_abc — Single vector for phase voltage components

scalar

Single vector representing the three-phase system voltage in the abc reference frame.

Dependencies

To enable this port, set Voltage input type to Vabc and clear the Expand voltage input parameter.

Data Types: single | double | fixed point

V_dc — DC bus voltage

scalar

Variable DC bus voltage (in volts).

Dependencies

To enable this port, set Input units parameter to SI unit

Data Types: single | double | fixed point

Output

V_ao — a-axis output inverter pole voltage

scalar

Output inverter pole voltage component along a-axis of the abc reference frame.

Dependencies

To enable this port, select the Voltage (a,b,c) parameter and select the Expand outputs parameter

Data Types: single | double | fixed point

V_bo — b-axis output inverter pole voltage

scalar

Output inverter pole voltage component along b-axis of the abc reference frame.

Dependencies

To enable this port, select the Voltage (a,b,c) parameter and select the Expand outputs parameter

Data Types: single | double | fixed point

V_co — c-axis output inverter pole voltage

scalar

Output inverter pole voltage component along c-axis of the abc reference frame.

Dependencies

To enable this port, select the Voltage (a,b,c) parameter and select the Expand outputs parameter

Data Types: single | double | fixed point

V_abco — Single vector representing output inverter pole voltage (abc reference frame)

vector

Single vector representing output inverter pole voltage in abc reference frame.

Dependencies

To enable this port, select the Voltage (a,b,c) parameter and clear the Expand outputs parameter

Data Types: single | double | fixed point

M_abc — Modulation signal for abc stator reference voltage

vector

Modulation signal for abc stator reference voltage.

Data Types: single | double | fixed point

D_abc — Duty cycle for abc stator reference voltage

vector

Duty cycle for abc stator reference voltage.

Data Types: single | double | fixed point

Parameters

Parameters

Modulation method — Pulse-width modulation (PWM) methods

SVM: space vector modulation (default) | SPWM: sinusoidal PWM | 60 DPWM:60 degree discontinuous PWM | 60 DPWM (+30 degree shift):+30 degree shift from 60 DPWM | 60 DPWM (-30 degree shift):-30 degree shift from 60 DPWM | 30 DPWM: 30 degree discontinuous PWM | 120 DPWM: positive DC component | 120 DPWM: negative DC component

Pulse-width modulation (PWM) method that the block uses to modulate the input stator phase or reference voltages.

Voltage input type — Voltage input type based on reference frames

Valphabeta (default) | Vabc

Type of three-phase stator voltage representation that the block uses as input. Select either the abc or αβ reference frame.

Expand voltage input — Option to expand input voltage to its reference components

on (default) | off |

Option to expand input voltage to its reference components (abc reference frame or αβ reference frame).

Input units — Unit of input voltages

Per-unit (default) | SI unit

Unit of input voltages used in the block. See Per-Unit System for more details.

Note

When the input units are set to Per-unit, the block introduces a gain of $$\frac{2}{\sqrt{3}}\left[\frac{{{\displaystyle V}}_{out}}{{{\displaystyle V}}_{in}}\right]$$ when SVM or any DPWM method is selected.

Limit modulation signal (Range: -1 to +1) — Option to limit the modulation signal in the [-1,1] range

off (default) | on

Option to limit the modulation signal in the [-1,1] range.

Dependencies

This parameter is configurable only if you select Per-unit for the Input units parameter.

Outputs

Voltage (a,b,c) — Option to show voltage output ( abc reference frame)

on (default) | off

Option to show voltage ( abc reference frame) as output port.

Modulation signal (a,b,c) — Option to show instantaneous modulation signal ( abc reference frame) as output port

off (default) | on

Option to show instantaneous modulation signal ( abc reference frame) as output port.

Duty cycle (a,b,c) — Option to show PWM duty cycle ( abc reference frame) as output port

off (default) | on

Option to show PWM duty cycle ( abc reference frame) as output port.

Expand outputs — Option to expand output voltage to its phase components

on (default) | off |

Option to expand output voltage to its phase components (abc reference frame).

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

HDL Code Generation

Generate VHDL, Verilog and SystemVerilog code for FPGA and ASIC designs using HDL Coder™.

HDL Coder™ provides additional configuration options that affect HDL implementation and synthesized logic.

Supported Block Parameters

For HDL code generation with the PWM Reference Generator block, set the Modulation method to SVM: space vector modulation or SPWM: sinusoidal PWM.

HDL Architecture

This block has one default HDL architecture.

HDL Block Properties

ConstrainedOutputPipeline	Number of registers to place at the outputs by moving existing delays within your design. Distributed pipelining does not redistribute these registers. The default is 0. For more details, see ConstrainedOutputPipeline (HDL Coder).
FlattenHierarchy	Remove PWM Reference Generator block hierarchy from generated HDL code. The default is inherit. See also FlattenHierarchy (HDL Coder).
InputPipeline	Number of input pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see InputPipeline (HDL Coder).
OutputPipeline	Number of output pipeline stages to insert in the generated code. Distributed pipelining and constrained output pipelining can move these registers. The default is 0. For more details, see OutputPipeline (HDL Coder).
SharingFactor	Number of functionally equivalent resources to map to a single shared resource. The default is 0. See also Resource Sharing (HDL Coder).

Fixed-Point Conversion
Design and simulate fixed-point systems using Fixed-Point Designer™.

Version History

Introduced in R2020a