Voltage source inverter output voltage error compensation

摘要

An electrical device such as a motor is controlled by means of a pulse width modulator (PWM) inverter. Errors in output voltage due to switching dead time and conduction losses are compensated by measuring the inverter voltage output over a full pulse period; comparing it with a demand voltage to determine an error and applying compensation to the voltage output of the inverter dependent on said error. Compensation may be applied to the inverter by lengthening or shortening the periods of the voltage pulse from the inverter. The output may be integrated over, and synchronised with, one or more PWM periods. The output may be measured using a counter, a DC link voltage and sigma delta analogue to digital conversion. The demand voltage may similarly be determined by counting the logic level of the PWM output stage, over the same time period as the output voltage is measured.