Parallelable PWM amplifier

A modular pulse-width modulation (PWM) power amplifier parallelable up to 47-KW peak is being used in magnetic resonance imaging (MRI), dc servo, audio, and other electromagnetic applications. Each of two independent half bridges in a module contains its own output filters and a multiple loop feedback system that equalizes power sharing, damps load resonance, and is switchable to either voltage or current control. During the development, a nondestructive power MOSFET dv/dt tester was devised.