Series resonance inverter and implementation method thereof

Abstract

The invention provides a series resonance inverter and an implementation method of the series resonance inverter. The implementation method of the series resonance inverter comprises the steps that control over starting and stopping of four switching devices of the series resonance inverter is carried out through alternate switching between PWM modulation and non-PWM modulation, wherein the starting frequency and the stopping frequency of the switching devices are adjusted according to resonance current. The process of alternate switching comprises at least two switching periods, wherein in one of the switching periods, two paths of driving signals are used for driving two switching devices of an upper edge bridge to carry out non-PWM modulation so that the two switching devices can work with a preset duty ratio, the other two paths of driving signals are used for driving two switching devices of a lower edge bridge to carry out PWM modulation; in the other switching period, the two paths of driving signals are used for driving the two switching devices of the lower edge bridge to carry out non-PWM modulation so that the two switching devices can work with the preset duty ratio, and the other two paths of driving signals are used for driving the two switching devices of the upper edge bridge to carry out PWM modulation. The series resonance inverter and the implementation method of the series resonance inverter can be beneficial to achieving loss balance of the switching devices and the design of heat dissipation structures of the switching devices.

Description

technical field [0001] The present invention relates to the field of electronic technology, and more specifically, to a series resonant inverter and an implementation method thereof. Background technique [0002] Nowadays, in the high-voltage power supply of X-ray machines, the series resonant inverter circuit is the commonly used topology. In the series resonant circuit, the design of the switch loss and heat dissipation structure is the core of the series resonant circuit. Therefore, how to reduce the switching loss and optimize the design of the heat dissipation structure has always been the main problem faced by the series resonant circuit. [0003] In the existing high-voltage power supply, a full-bridge series resonant circuit, phase-shift control, and alternate switching between the leading arm and the lagging arm are used to solve the problem of equalizing loss of the switch. Its switch adopts phase-shift PWM control. Since this phase-shift control is an asymmetrica...

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Problems solved by technology

Its switch adopts phase-shift PWM control. Since this phase-shift control is an asymmetrical control method, its advanced forearm and lagging arm are switched in turn, and each switching device will have a zero-voltage turn-on and a zero-voltage switch-on every two switching cycles. turn off, and its switching frequency remains unchanged, which will inevitably cause different degrees of switching loss to the switching device, which makes the design of the heat dissipation structure more difficult.

[0004] In order to achieve the balanced loss of the switch, the principle that the RCD Snubber circuit only works at the transition moment of the switch can effectively improve the switching track of the switching device and reduce the rising rate of its turn-off voltage, thereby transferring the loss of the switching device to the RCD Snubber circuit In order to reduce the loss of switching devices and improve the reliability of the circuit, to achieve the purpose of switching loss balance, but because of its own loss, it is also limited by the size of the inverter, such as relying solely on The RCD Snubber circuit must bear a large stress, so the effect of achieving switching loss equalization is not ideal

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