Buck terminal coupled inductor buck-boost conversion circuit and control method thereof

A buck-boost conversion, coupled inductance technology, applied in the direction of adjusting electrical variables, control/regulating systems, converting DC power input to DC power output, etc., can solve problems such as unfavorable efficiency and reduction, and achieve a simple and high-efficiency control scheme. , easy to achieve effect

Inactive Publication Date: 2019-06-28
IANGSU COLLEGE OF ENG & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the power switching tubes of the existing dual-tube Buck-Boost converter usually work in a hard switching state, which is not conducive to further improving efficiency and reducing EMI
[0004] The purpose of the present invention is to solve the hard switching problem of the switching tube and the diode in the Buck circui

Method used

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  • Buck terminal coupled inductor buck-boost conversion circuit and control method thereof
  • Buck terminal coupled inductor buck-boost conversion circuit and control method thereof
  • Buck terminal coupled inductor buck-boost conversion circuit and control method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] refer to Figure 1-2, a buck-side coupled inductance-type buck-boost conversion circuit and control method, which includes an input DC voltage source 1, a step-down circuit 2, a coupling inductor 3, a boost circuit 4, an output filter capacitor 5, and a voltage loop controller 6 , current loop controller 7 and PWM generator 8, it is characterized in that: input DC voltage source 1 comprises input DC voltage source Uin, the positive pole of input DC voltage source Uin is connected with the drain electrode of first power switch tube S1 and the second power respectively The drains of the switching tube S2 are connected; the step-down circuit 2 includes the first power switching tube S1, the first freewheeling diode D1, the second power switching tube S2, the second freewheeling diode D2, and the source of the first power switching tube S1 The pole is connected to the cathode of the first freewheeling diode D1, and the junction of the two is connected to the end of the same...

Embodiment 2

[0035] refer to image 3 -4, Since the coupling coefficient of the coupled inductor is not less than 0.9, the mutual inductance LM of the coupled inductor is much larger than the two leakage inductances (L1-LM, L2-LM) in the coupled inductor, so the two leakage inductances (L1-LM, During the commutation process of L2-LM) current (iL1, iL2), the current in the mutual inductance LM of the coupled inductor can be regarded as a constant current source; and the inductance L1 of the coupled inductor is assumed to be L2. Therefore, the working principle of the buck-side coupled inductive buck-boost conversion circuit and control method described in Embodiment 1 is briefly described as follows:

[0036] 1. Working mode (1) (t1-t2 time period)

[0037] Such as image 3 And shown in Figure 4(a). At time t1, the first power switch S1 and the third power switch S3 are turned on. Under the action of the input DC voltage source voltage Uin, the current iL1 on the leakage inductance L1-LM...

Embodiment 3

[0049] refer to Figure 5-7 . The main simulation experiments are done with a buck-side coupled inductive buck-boost conversion circuit and control method described in embodiment 1 and embodiment 2.

[0050] The simulation parameters are as follows: the input DC voltage source voltage Uin is 20V-60V, the output voltage Uout is controlled at 28.5V, the switching frequency of the first power switch S1 and the second power switch S2 is 50kHz, and the third power switch S3 is 100kHz , the inductors L1 and L2 in the coupled inductor are 24μH, the coupling coefficient is 0.9, the output filter capacitor C is 940μF, and the load R is a 5.6Ω resistive load.

[0051] Figure 5 The simulation waveforms of the input DC source voltage Uin and the output voltage Uout when the input DC source voltage Uin varies between 20V and 60V are given. It can be seen that when the input DC source voltage Uin changes, the output voltage Uout can be stabilized at 28.5V. When the input DC source volt...

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PUM

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Abstract

The invention discloses a Buck terminal coupled inductor buck-boost conversion circuit and belongs to the DC non-isolated conversion technology, and the stable output voltage can be achieved in a wideinput voltage range. According to the invention, a coupled inductor, three power switch tubes and three freewheeling diodes are mainly used to achieve a buck-boost function, and the stable output voltage is ensured. In the present invention, the current in a Buck terminal coupled inductor operates in a discontinuous mode, the zero-current turn-on of two power switch tubes of a Buck terminal and the zero-current turn-off of two freewheeling diodes of the Buck terminal can be achieved, the problem of the reverse recovery of two diodes at the Buck terminal is eliminated, therefore, the soft switching function is realized, and the efficiency of the conversion circuit is improved. The current sharing control is not required, and even if the duty ratios of the two power switch tubes of the Buckterminal are slightly different, the uniform current of two inductor currents in the coupled inductor can be realized. The invention is suitable for applications such as wide input electric vehicles,fuel cells, photovoltaic power generation, wind power generation and other new energy supply systems.

Description

technical field [0001] The invention relates to a DC non-isolated conversion device in a power conversion device, more specifically, it relates to a non-isolated DC buck-boost converter. Background technique [0002] Fuel cell power supply, new energy power generation (photovoltaic power generation, wind power generation, etc.), new energy vehicles, etc. have been vigorously developed. However, these occasions have a common feature: with the change of external natural conditions and the use environment, their output voltage fluctuates in a large range, and usually cannot directly supply power to the load. Therefore, a wide-input voltage power converter is needed as their post-stage converter, which can provide high-quality electric energy to electrical equipment after its voltage stabilization. The wide input voltage power converter has a buck-boost function, that is, a buck-boost power converter. [0003] Among the buck-boost power converters, there are isolated flyback c...

Claims

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Application Information

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IPC IPC(8): H02M3/158
CPCY02E10/56Y02E10/76
Inventor 张先进朱海荣宋永献范才红
Owner IANGSU COLLEGE OF ENG & TECH
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