Soft switch auxiliary circuit and three-level and three-phase zero voltage conversion circuit

Abstract

The invention discloses a soft switch auxiliary circuit. The soft switch auxiliary circuit comprises an auxiliary coupling inductor, a clamping diode and an auxiliary switch tube, wherein the auxiliary coupling inductor is configured to receive a circuit from each branch of a main circuit connected with the soft switch auxiliary circuit and performing current sharing output, the clamping diode isconfigured to receive an inductance voltage from the auxiliary coupling inductor and feeding the inductance voltage back to the main switch tube of the main circuit, and the auxiliary switch tube is configured to receive a current from the main switch tube of the main circuit and outputting the current to the clamping diode. The invention also discloses a three-level and three-phase zero voltage conversion circuit. By the soft switch auxiliary circuit, the loss of a hard switch can be reduced, the switch frequency of the system is increased, the efficiency is improved, and the electromagneticinterference is reduced.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a soft switch auxiliary circuit and a three-level three-phase zero-voltage conversion circuit. Background technique [0002] The development direction of power electronic devices is miniaturization, light weight, high efficiency and low cost. In the past, the method of increasing the switching frequency is usually used to achieve this goal, but this will bring problems such as additional switching loss, electromagnetic interference noise, ringing, etc.; multi-level conversion technology achieves a more effective reduction under the same switching frequency The volume and weight of the output filter are reduced, and at the same time, the harmonic content in the output waveform is effectively reduced, the switch stress is reduced, and the efficiency can be improved within a certain range. The three-level circuit has been widely used in communication power supp...

AI Technical Summary

Problems solved by technology

In the past, the method of increasing the switching frequency is usually used to achieve this goal, but this will bring problems such as additional switching loss, electromagnetic interference noise, ringing, etc.; multi-level conversion technology achieves a more effective reduction under the same switching frequency The volume and weight of the output filter are reduced, and at the same time, the harmonic content in the output waveform is effectively reduced, the switch stress is reduced, and the efficiency can be improved within a certain range. The three-level circuit has been widely used in communication power supplies, uninterruptible power supply UPS, photovoltaics, etc. power electronics power supply

[0003] With the increasing demand for high efficiency, high power density, and low cost, the use of high-performance devices to increase switching frequency and multi-level technology still cannot meet the needs of market competition

In the application of high-performance devices, increasing the switching frequency can reduce the volume of passive device inductance, transformers and capacitors, but at the same time it will increase the switching loss, so it is difficult to guarantee whether the efficiency will be improved, and it is impossible to meet high power density and high power consumption at the same time. Efficiency requirements, the operating frequency of existing common devices is limited, even with the development of high-performance devices SiC, GaN, the operating frequency can be increased to 100kHz or even MHz, but the application of high-performance devices has a great impact on PCB layout, drive, and The requirements for technologies such as source clamping are more stringent. From the perspective of existing power electronics technology, the application and promotion of high-performance devices still need a long way to go. The stability and cost of device applications are the key constraints

Topologies such as multi-level technology, interleaving, and multi-state are proposed to improve efficiency to a certain extent, but they still cannot meet market demand. In order to achieve high efficiency, high power density, and low cost, it is necessary to solve the switching loss of switching devices based on reality. Large size, large heat sink, low system operating frequency, large size of magnetic core components, ordinary power devices MOSFET or IGBT are developing rapidly, and their performance and loss are gradually decreasing, but hard switching is still the system with high power density, high efficiency, Low cost is a bottleneck, so the research and application of soft switching will open up a newer field for related power electronic products

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