Starting control method of inverter circuit comprising coupling transformer

Abstract

The invention provides a starting control method of an inverter circuit comprising a coupling transformer, the inverter circuit comprises a positive bus, a negative bus, a first switch bridge arm, a second switch bridge arm, a coupling transformer and a coupling inductor, the starting method comprises the following steps: setting an initial switching frequency f1 of a switching tube in the first switch bridge arm and the second switch bridge arm; carrying out soft start wave sending at an initial switching frequency f1, gradually reducing the switching frequency to a normal working frequency f2, ending a frequency reduction process, keeping the normal working frequency f2 to continue driving, and taking a high switching frequency as a switching tube starting frequency, so that the time acting on the transformer is shortened, the smaller the magnetic density generated in a magnetic core of the coupling transformer is, and the magnetic core is not easy to saturate; the excitation inrush current generated when the inverter circuit comprising the coupling transformer is started can be remarkably reduced, so that the reliability of the inverter circuit is improved, the magnetic core utilization rate of the transformer can be effectively improved, and the size and the cost of the inverter circuit are reduced.

Description

technical field [0001] The invention belongs to the technical field of power electronic power supplies, and relates to a start-up control method of an inverter circuit, in particular to a start-up control method of an inverter circuit including a coupling transformer. Background technique [0002] The inverter circuit (Inverter Circuit) corresponds to the rectifier circuit (Rectifier Circuit), which is designed to convert direct current into alternating current. In recent years, inverter circuits have been widely used in industry, among which the application of half-bridge inverter circuits in DC to AC power supplies is the most prominent. [0003] In the traditional half-bridge inverter circuit, a fixed switching frequency is generally used for soft start, but if a coupling transformer is added to the inverter circuit, and the traditional fixed switching frequency is used for soft start, the coupling transformer is easy to cause the Due to the double magnetic flux effect a...

AI Technical Summary

Problems solved by technology

[0003] In the traditional half-bridge inverter circuit, a fixed switching frequency is generally used for soft start, but if a coupling transformer is added to the inverter circuit, and the traditional fixed switching frequency is used for soft start, the coupling transformer is easy to cause the Saturated by the double magnetic flux effect, the coupling transformer will generate an excitation inrush current, and even cause damage to the switching network connected to the coupling transformer in severe cases

[0004] The existing relatively simple solution is to design and reduce the working magnetic density of the transformer, but the disadvantage of this method is that it will reduce the utilization rate of the magnetic core, resulting in a larger volume of the magnetic core and higher cost

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