A modular rectifier system with 1 MHz conversion frequency

Abstract

A rectifier design is presented which incorporates a high-frequency conversion technology known as a quasi-resonant zero-current switcher. The power structure of this technology has been developed to allow very high speed operation; in this case the top end conversion frequency is 1 MHz. The zero-current switch technology substantially reduces switching losses in the primary switch of the circuit as well as reducing EMI (electromagnetic interference) generated in the switching process by controlling the di/dt of the system. This is accomplished by creating a resonant circuit that maintains a sinewave shape in the primary circuit. The actual operation of the primary switch is synchronized to the current waveform so that the simultaneous presence of voltage and current is permitted in the primary switch. The actual rectifier design consists of a series of conversion 'cells' operated in parallel and optimized for thermal and electrical performance. The cell groupings are then formed into a single 6 A rectifier module. This module is designed as part of a redundant rectifier system. An example would be a two-card system which would provide either 12 A or a redundant 6 A. The rectifier modules are designed for 'hot' replacement while on-line.<>