Wireless power transmission device based on class-D power amplifier

Abstract

The invention relates to a wireless power transmission device based on a class-D power amplifier. The class-D power amplifier is utilized to topologically design a magnetic-coupling resonant wirelesspower transmission system, and an impedance matching method for increasing the system output power is put forward. Two switching tubes are topologically adopted by the class-D power amplifier. Under an ideal condition, the two switching tubes can work under a zero-voltage-switching soft switching condition, and the transmission efficiency is high; meanwhile, when loads are changed, the work stateof the class-D power amplifier is not influenced. Compared with a bridging-type inverter, the topological structure is simple and high in efficiency. Compared with a class-E power amplifier, the class-D power amplifier solves the problem of load sensitivity, and voltage stress borne by the switching tubes when the switching tubes are switched off is much smaller than that borne by switching tubesof the class-E power amplifier, so that the output power is increased; meanwhile, the requirement for parameter design is low, and as is shown by a simulation result, the suggested impedance matchingcircuit can effectively increase the system output power.

Description

technical field [0001] The invention belongs to the technical field of wireless power transmission, and relates to a wireless power transmission device based on a class D power amplifier, in particular to a magnetic coupling series resonant wireless power transmission device based on a class D power amplifier. Background technique [0002] Wireless power transmission technology, also known as non-contact power transmission technology, is to realize the effective transmission of power from the power supply end to the load end in the form of no electrical direct contact. At present, according to different transmission mechanisms, wireless power transmission technology can be mainly divided into microwave type, electric field coupling type, electromagnetic induction type and magnetic coupling resonance type. The principle of the microwave type is to use microwave beams instead of wires for energy transmission, but microwaves will generate losses when transmitted in the air, can...

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Problems solved by technology

The bridge inverter power supply has large output power and good power characteristics, but the number of switch tubes is large, the drive is complicated and the loss is high

In contrast, the class E topology only needs one switch tube, which is easy to design under soft switching working conditions, and has a simple structure and high efficiency. It is 3.562 times of the DC power supply voltage. In order to ensure that the switch tube is not broken down, the DC power supply voltage should not be too large, resulting in limited output power

In addition, class E power amplifiers have high requirements for parameter design, and parameter design is very complicated. There is a theoretical optimal load resistance R in class E power amplifiers. opt , only when the actual load resistance R L The resistance value and R opt When the two are equal, the class E power amplifier works in the best state, when the two are not equal, especially when R L >R opt , the transmission power and efficiency of the system will be significantly reduced, and the class E power amplifier is suitable for working under constant load conditions, sensitive to load changes, and demanding working conditions

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