Induction type wireless electric energy transmission system capable of outputting constant current and constant voltage

Abstract

The invention discloses an induction type wireless electric energy transmission system capable of outputting constant current and constant voltage. The system is composed of a transmitting part and a receiving part. A constant-current and constant-voltage switching circuit (I) of the transmitting part is characterized in that a primary constant-voltage capacitor (CPv) is serially connected between a high-frequency inverter (H) and a primary coil (LP); after an additional parallel capacitor (CPp) is serially connected with a first switch (S1), an assembly which is composed of the additional parallel capacitor and the first switch is parallelly connected with a primary constant-voltage capacitor (CPv); the control end of the first switch (S1) is connected with a first controller (K1); or a primary constant-current capacitor (CPi) and an additional serial capacitor (CPs) are successively connected serially between the high-frequency inverter (H) and the primary coil (LP); a second switch (S2) is parallelly connected with the additional serial capacitor (CPs); and furthermore the control end of the second switch (S2) is connected with a second controller (K2). The induction type wireless electric energy transmission system can output constant current and constant voltage and furthermore has advantages of convenient control, high system operation stability, simple structure and low manufacture cost.

Description

technical field [0001] The invention relates to an inductive wireless power transmission system capable of outputting both constant current and constant voltage. Background technique [0002] Inductive wireless power transmission technology provides flexible, safe and reliable power supply to electrical appliances in a non-contact manner through a magnetic field, avoiding safety problems such as contact sparks and leakage in traditional plug-in power transmission systems. The technology is already widely used in built-in medical devices, consumer electronics, lighting and electric vehicles. Among them, the use of inductive wireless power transfer systems for wireless charging of batteries has great development prospects. [0003] In order to achieve safe charging of the battery, prolong the service life of the battery and the number of charge and discharge times, it usually mainly includes two charging stages of constant current and constant voltage. That is, the constant ...

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Problems solved by technology

Since the equivalent impedance of the load (battery) changes, it is difficult for the system to output the constant current or voltage required by the load under a certain input voltage.

In order to solve this problem, there are usually two methods: 1. Introduce closed-loop negative feedback control in the circuit system, such as adding a controller before the inverter to adjust the input voltage or adopting phase-shift control, or adding a negative feedback control after the secondary coil rectification DC-DC converter; its disadvantage is that it increases the cost and complexity of control and reduces the stability of the system

2. Using frequency conversion control, the system works at two different frequency points to achieve constant current and constant voltage output, but this method will cause frequency bifurcation, resulting in unstable system operation

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