Electric bridge circuit used for inverter or rectifier

Abstract

The invention discloses an electric bridge circuit used for an inverter or a rectifier, and relates to the technical field of power electronics. The electric bridge circuit comprises a first switch, asecond switch, a third switch and a fourth switch which are connected in series and electrically connected between positive and negative direct current voltage sources, wherein the first switch and the second switch are in anti-parallel connection with a first diode; the first switch and the second switch at least comprise a combined field effect transistor; the third switch and the fourth switchare in anti-parallel connection with a second diode; the third switch and the fourth switch at least comprise a combined field effect transistor; the combined field effect transistor comprises a highvoltage withstand field effect transistor and a low voltage withstand field effect transistor with electrically connected sources or drains. Parasitic diodes in the combined field effect transistor are in series-opposing connection, so that the access of a follow current in the parasitic diodes is blocked, so that switch loss and spike voltage caused by the follow current are reduced.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a bridge circuit. Background technique [0002] Pulse Width Modulation (PWM) inverters are currently widely used in the field of power electronics, especially in the fields of uninterruptible power supplies, solar inverters, wind energy converters, motor drives, and fuel cells. Phase three-level inverters are the most widely used. In the prior art, a bridge circuit for a single-phase three-level inverter usually uses four field effect transistors as switches, or four bipolar transistors are respectively connected in antiparallel with diodes as switches. Among them, the disadvantage of using bipolar transistors and diodes in reverse parallel as switches is that peak voltages are generated under high-speed switching, which may cause breakdown of components, so the switching frequency is limited and the switching speed is slow; The switching speed is fast, but due to the...

AI Technical Summary

Problems solved by technology

Among them, the disadvantage of using bipolar transistors and diodes in reverse parallel as switches is that peak voltages are generated under high-speed switching, which may cause breakdown of components, so the switching frequency is limited and the switching speed is slow; The switching speed is fast, but due to the very poor reverse recovery characteristics of the internal parasitic diode, when the current flows through the parasitic diode, the reverse recovery current generated by the parasitic diode will cause problems such as increased switching loss and output voltage spikes, etc. affect the output voltage and reduce the lifetime of the switch

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