Advanced Electric Drives: Analysis, Control, and Modeling Using MATLAB/Simulink

8Space Vector Pulse Width-Modulated (SV-PWM) Inverters

8-1    Introduction

In Chapter 5, we briefly discussed current-regulated pulse width-modulated (PWM) inverters using current-hysteresis control, in which the switching frequency f_s does not remain constant. The desired currents can also be supplied to the motor by calculating and then applying appropriate voltages, which can be generated based on the sinusoidal pulse-width-modulation principles discussed in basic courses in electric drives and power electronics [1]. However, the availability of digital signal processors in control of electric drives provides an opportunity to improve upon this sinusoidal pulse-width modulation by a procedure described in this chapter [2,3], which is termed space vector pulse-width modulation (SV-PWM). We will simulate such an inverter using Simulink for use in ac drives.

8-2    Synthesis of Stator Voltage Space Vector

In terms of the instantaneous stator phase voltages, the stator space voltage vector is

(8-1)

In the circuit of Fig. 8-1, in terms of the inverter output voltages with respect to the negative dc bus and hypothetically assuming the stator neutral as a reference ground

(8-2)

Fig. ...