A method and system for improved thermal management of a voltage source inverter operating at a low output frequency using a null vector modulation technique

摘要

A method for thermal management in a voltage source inverter (110) comprising a plurality of branches and switches (111-123) for controlling the flow of current in respective portions of the branches, the method comprising: sensing (520) a low output frequency condition; Determining (530) a zero vector modulation in response to the sensed low output frequency condition, a zero vector modulation frequency (fZVM) and a zero vector modulation duty cycle (dZVM) being selected taking into account the total power dissipation in the branch carrying the highest current; and applying (540) the determined zero vector modulation to reduce the heat load in the voltage source inverter (110), wherein applying the zero vector modulation comprises periodically alternating the zero state switching space vectors (V0, V7) of a first and a second zero state Zero vector modulation frequency (fZVM) and the zero vector modulation duty cycle (dZVM) can be selected.