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Current detection method and device for LLC resonance circuit

A technology of a current detection device and a resonant circuit is applied in the direction of measurement device, measurement of current/voltage, measurement of electrical variables, etc., which can solve the problems of non-current shunt, high frequency, large primary current, etc., and achieves simple structure, low cost, Easy-to-control effects

Active Publication Date: 2013-01-30
VERTIV CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the case of low voltage (72V) input and high voltage (380V) output, due to the large current and high frequency of the primary side, the shunt is not an ideal choice.

Method used

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  • Current detection method and device for LLC resonance circuit
  • Current detection method and device for LLC resonance circuit
  • Current detection method and device for LLC resonance circuit

Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment approach 1

[0019] Such as figure 1 As shown, an LLC resonant circuit includes a resonant inductor Lr, a main transformer T, a resonant capacitor Cr, main power switching devices Q201, Q202, Q203, and Q204, and secondary power fast recovery diodes D271, D272, D273, and D274. The LLC resonant circuit is connected with a DC input voltage Ui. The main power switching devices Q201, Q202, Q203, Q204 have internal parasitics or additional freewheeling diodes and capacitors. The secondary side of the transformer of the LLC resonant circuit is connected to double busbars, namely the positive busbar BUSS+ and the negative busbar BUSS-.

[0020] The LLC resonant circuit can realize the zero-voltage turn-on (ZVS) of the main power switch devices Q201, Q202, Q203, Q204 and the zero-current turn-off of the secondary side diodes by controlling the switching frequency of the main power switch devices Q201, Q202, Q203, and Q204. (ZCS), so that the operating frequencies of the main power switching devic...

specific Embodiment approach 2

[0031] Such as figure 2 As shown, the difference between this specific embodiment and the first specific embodiment is that: the rectifier includes a first diode D1, and the sampling resistor includes a first resistor R1 and a second resistor R2; the first diode The anode of the tube D1 is connected between the first end of the resonant capacitor Cr and the main transformer T of the LLC resonant circuit, the cathode is connected to the second resistor R2, and the first resistor R1 is connected to the second end of the resonant capacitor Cr.

[0032] The first diode D1 is a fast recovery diode or a Schottky diode.

specific Embodiment approach 3

[0033] Such as image 3 As shown, the difference between this specific embodiment and the first specific embodiment is that: the rectifier includes a first diode D1, and the sampling resistor includes a first resistor R1 and a second resistor R2; the first diode The anode of the tube D1 is connected between the second end of the resonant capacitor and the main power switching device of the LLC resonant circuit, the cathode is connected to the first resistor R1, and the second resistor R2 is connected to the first end of the resonant capacitor Cr.

[0034] The first diode D1 is a fast recovery diode or a Schottky diode.

[0035] A current detection method for an LLC resonant circuit, comprising the steps of indirectly detecting the current of the resonant circuit by detecting the voltage of the resonant capacitor, i = C du dt , Among them, i is the current of the resonant circuit, C is the capa...

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PUM

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Abstract

The invention discloses current detection method and device for an LLC resonance circuit, wherein the method comprises the following step: indirectly detecting the current of a resonance loop by detecting the voltage of a resonant capacitor according to a formula of i=C(du / dt), wherein i is the current of the resonance circuit, C is the capacitance value of the resonant capacitor, and u is the voltage of the resonant capacitor. The device comprises a rectifier and a sampling resistor, wherein the rectifier is used for rectifying the voltage on the resonant capacitor, and rectified voltage is sampled by the sampling resistor. The invention does not need two sampling circuits to respectively sample the current of a positive bus and a negative bus, thereby reducing the design cost and havingconvenient control. The invention can indirectly reflect the amount of the current of the resonance loop and effectively detect the current of the resonance loop so as to timely carry out uninterrupted current-limiting protection on a main loop and prevent damaging a main power switch under a limited condition due to overcurrent. Moreover, the invention has simple structure and low cost and can effectively improve product competitiveness.

Description

technical field [0001] The invention relates to a current detection method for an LLC resonant circuit, and also relates to a current detection device for an LLC resonant circuit. Background technique [0002] At present, the development trend of switching power supply is: high frequency miniaturization, high power density, high efficiency and low cost. However, due to the fact that the semiconductor device is in a hard switching state, the traditional switching circuit has a very large loss and cannot improve its own efficiency, so that it is bulky and gradually loses its market competitiveness. The soft-switching circuit topology has become the choice of most switching power supply manufacturers to improve product competitiveness. There are many researches and patents on soft-switching circuits, among which the LLC resonant circuit is favored by many switching power supply industry personnel. The secondary side of the LLC resonant circuit transformer is connected to doubl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R19/00
Inventor 糜晓宇肖学礼林清森
Owner VERTIV CORP