A family of ZVS inverters with load adaptive fixed timing control.

摘要

Zero voltage switching (ZVS), as one of the soft switching techniques, effectively reduces the switching losses and stress on power devices and electromagnetic interference in power electronics system. In this dissertation, a family of zero voltage switching inverters, including the auxiliary resonant commutated pole (ARCP) inverter, resonant snubber inverter (RSI), and coupled inductor ZVS inverter, was studied through theoretical analysis and implementation.; In this family of ZVS inverters, an auxiliary resonance is created by the resonant circuitry before commutation from a diode to a transistor. The transistor is turned on when a resonant current flows through the diode connected in anti-parallel with the transistor with the turn-on voltage clamped by the diode to be zero. At turn-off, the switching losses are reduced by the snubber capacitors across the switches.; In spite of the differences in topologies of these three ZVS inverters, the analysis shows that the same equivalent circuit model describes the behavior during commutation. With the load in parallel with the capacitor of the resonant tank, this equivalent circuit model has the same features as the parallel resonant DC-DC converter. Thus, state plane analysis with normalization, which has been successfully used to analyze resonant DCDC converters, was applied to analyze this family of ZVS inverters.; The initial condition of the resonance is controlled by the duration of the charging mode during the commutation. With a fixed timing control scheme, this duration is the same, which leads to the same peak value of the resonant current regardless of the amplitude of the load current. The conduction losses of the resonance are slightly higher than for the variable timing control, which has variable duration for the charging mode and a different peak value for the resonant current according to the instantaneous amplitude of the load current. The fixed timing control scheme has the advantage of minimum hardware requirement with only the information of the commutation type necessary to control the auxiliary switches.; The RSI is constructed as a single-phase inverter for a 1kW Uninterruptible Power Supply (UPS), and the other two are utilized to drive motors. Using an Analog Devices ADMC401 Digital Signal Processing evaluation board, both Space Vector Pulse Width Modulation (SVPWM) and Sinusoidal Pulse Width Modulation (SPWM) control schemes were implemented in combination with the ZVS control circuitry and software. The RSI is suitable for single-phase applications with minimum cost. (Abstract shortened by UMI.)