Power converting device

Abstract

The present invention discloses a power conversion apparatus comprising a control circuit for generating a switching signal at the timing allowing soft-switching to be achieved, and free from any occurrence of ripple. The power conversion apparatus includes a first main switch (Q1) and a second main switch (Q2) which are connected in series with each other. One of the ends of the first main switch is connected with the positive side of a DC power supply, and one of the ends of the second main switch is connected to the negative side of the DC power supply. A diode (D1, D2) is connected in parallel with each of the main switches so as to become reverse biased with respect to the DC power supply. A main-switch snubber capacitor (C1, C2) is connected in parallel with each of the main switches. A load is connected with the junction between the pair of main switches, and the main switches are controllably switched according a switching signal from a control circuit to generate an output. A first auxiliary resonant circuit including serial-connected first and second auxiliary switches (Q3, Q4, Q5, Q6) and a resonant inductor (L1) connected in series with the second auxiliary switch is connected with each of the positive side of the DC power supply and the junction between the two main switches. A diode is connected to each of the first and second auxiliary switches so as to become reverse biased with respect to the DC power supply. The control circuit provides a turn-on signal to the first and second auxiliary switches according to a voltage signal as an input representing the voltage across each of the main switches and auxiliary switches from voltage detecting means before a turn-on signal as the switching signal is provided to the first main switch.

Description

technical field [0001] The present invention relates generally to current conversion devices. More specifically, the present invention relates to a power conversion device including a control circuit capable of realizing soft switching of switching elements. Background technique [0002] In power conversion devices such as converters and inverters, circuits including soft switching functions are being developed for the purpose of reducing switching losses of switching elements and increasing switching frequencies. [0003] For example, in U.S. Patent No. 5,047,913, a converter with the following structure is disclosed: the voltage of the DC power supply is divided into a voltage of 1 / 2 by two capacitors connected in series, and the connection point of the capacitor is passed through a bidirectional switch and an inductor. connected to the connection point of two series-connected main switches. The load is connected to the connection point of the...

AI Technical Summary

Problems solved by technology

This control method is accompanied by the problem that ripple voltage is generated in the case of causing the power conversion device to perform inverter operation

If a capacitor is used for downsizing the device, a ripple voltage of the same cycle as the inverter output voltage occurs between the first potential and the second potential, causing the same problem as the circuit described in the aforementioned U.S. patent

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