Current Controlled PWM Inverter of High Current Response Speed and Low Harmonic Content.

This paper proposes a new current controlled inverter which keeps the harmonic current at a low level in the steady state and responds very quickly to the reference current signal in the transient state. In the steady state where the current deviation vector is small, the switching mode is selected which minimizes the time differentiation of current deviation vector thus reducing the harmonic content. The proposed methods has the following advantages over the conventional low harmonic inverter. (1) The current control circuit is very similar because the switching mode is determined only from the current deviation vector. (2) The circuit performance is not affected by the load constants and therefore it is very versatile. (3) The average switching frequency is kept constant by a switching frequency feed-back circuit. In the transient state where the current deviation vector becomes large, the switching mode is changed over the circuit is operated as a high response speed comparator. The proposed converter is applied to a permanent magnet type 1.5 kW synchronous motor to demonstrate its effectivenes. [ABSTRACT FROM AUTHOR]