Constant-current constant-voltage induction type wireless charging system based on variable secondary structure

Abstract

The invention discloses a constant-current constant-voltage induction type wireless charging system based on a variable secondary structure. In a receiving part of the system, a receiving coil Ls is sequentially connected with a compensation capacitor Cs, a compensation capacitor Cf, a compensation inductor Lf and a rectifier filter R in series; one end of the constant voltage compensation capacitor CSV, connected in series with a first change-over switch S1, is connected with a common point of the compensation capacitor Cs and the compensation capacitor Cf; and the other end of the constant voltage compensation capacitor CSV, connected in series with the first change-over switch S1, is connected with a common point of the receiving coil Ls and the rectifier filter R; one end of the constant-current compensation capacitor CSC, connected in series with a second change-over switch S2, is connected with a common point of the compensation capacitor Cs and the receiving coil Ls; the other end of the constant-current compensation capacitor CSC, connected in series with the second change-over switch S2, is connected with a common point of the compensation inductor Lf and the compensationcapacitor Cf. Constant-voltage and constant-current output of the system is achieved by controlling the states of the first change-over switch S1 and the first change-over switch S2.

Description

technical field [0001] The invention relates to an inductive wireless charging system. Background technique [0002] Inductive wireless power transfer technology is a new power supply method that transfers electrical energy to the load in a non-contact manner through the principle of electromagnetic induction. The non-contact charging technology of electric vehicles is gradually favored by enterprises and consumers due to its convenience, speed and safety. This technology can strengthen the competitiveness of electric vehicles compared with traditional fossil energy vehicles and promote the development of the electric vehicle industry. application and development prospects. [0003] In order to prolong the service life and charging times of the on-board battery and improve the safety of the charging system, the charging process of the battery is mainly divided into two charging modes: constant current and constant voltage: in the initial stage of charging, it is the constan...

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Problems solved by technology

In order to solve this problem, the usual methods are: 1. Adopt closed-loop feedback control in the circuit system, such as using communication equipment to feed back the rectified output DC voltage and current signals of the receiving side to the primary side control system. The converter adopts phase-shift control or PWM control to adjust the system output voltage and current; or adopts a high-frequency controllable rectifier on the receiving side to adjust the system output voltage and current by using phase-shift control or PWM control; it can also be rectified on the receiving side Post-cascaded DC-DC converter; its disadvantage is that it increases control cost and complexity, and reduces system stability

2. Adopt frequency conversion control to realize constant current and constant voltage output by adjusting the operating frequency of the system, but in a system with frequency bifurcation, this method is likely to cause unstable system operation

However, the ground side adopts the LCC compensation structure, and the high-order harmonic content of the inverter output current is relatively large, which increases the power capacity of the inverter, and the efficiency is low

The receiving side adopts the LCC compensation structure, and the input current of the rectifier will appear discontinuous, which will cause the output voltage of the system to change

[0009] In the document "Research and Design of Wireless Power Transmission System with Automatic Switching of Charging Mode Based on LCL Resonant Compensation Network [J]. Journal of Electrotechnical Society, 2018, 33(S1): 38-44." The compensation capacitor value realizes the automatic switching function of constant voltage and constant current charging, but does not consider the influence of the intermittent input current of the rectifier on the output voltage and current of the system

[0010] In the topology disclosed in Chinese patent 201610318334.2 "Inductive wireless power transfer system capable of outputting both constant current and constant voltage", the primary side and the receiving side adopt a series compensation structure at the same time, and the system has poor ability to resist parameter deviation and is robust Poor sex

Chinese patent 201610814192.9 "Constant current and constant voltage inductive wireless charging system based on variable primary parameters" discloses an inductive wireless charging system topology that can realize constant current and constant voltage charging, but the primary side of the structure uses series compensation, and the receiving side With LCC compensation, the compensation inductance on the receiving side must be designed according to the output current and the induced voltage on the receiving side, without considering the intermittent input current of the rectifier

When outputting constant current, the primary side and secondary side of the system are both series compensation structures, which have poor robustness; when outputting constant voltage, the receiving side is an LCC structure, which is prone to intermittent operation of the rectifier input current, resulting in constant voltage output When the output voltage cannot be guaranteed to be constant, this structure is not suitable for systems with a wide range of load changes

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