Average Power Stage
3-phase Average Power Stage
Library
GMCLIB
Description
Performs an Average Power Stage model taking into account a dead-time effect which is calculated from dead-time length, PWM frequency and DCbus voltage. Dead-time causes a voltage error which is added to the output voltage from power stage. This error voltage has an opposite phase than output current and is calculated as follows:
,where:
M - number of switching per one cycle
Td - dead-time length
T - length of one cycle
Vd - magnitude of DCbus voltage
f - PWM frequency
Dead-time effect for a sine wave is shown on the following picture. Dead-time is presented by constant voltage error added to (subtracted from) the sine wave. The step change occurs when output current crosses zero (changes its direction).
Parameters and dialog box
The Average Power Stage block dialog box appears as follows:
Td - dead-time length [s]
PWMps - PWM frequency [Hz]
Inputs and outputs
Inputs:
U in - vector of duty cycles for 3 phases (e.g. from SVM (range 0-1))
I in - vector of measured 3-phase current (scaling doesn't matter, signum is taken into account)
U DCbus - DCbus voltage (real units) [V]
Outputs:
U out - 3-phase output voltage (dedicated as an input to a motor) [V]