Three-phase PWM rectifier DC bus capacitor current reconstruction and capacity identification method

A DC bus capacitance and current reconstruction technology, which is applied in battery circuit devices, electric vehicle charging technology, charging stations, etc., can solve problems affecting system use and achieve the effect of reducing volume and cost

Active Publication Date: 2020-08-14
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, capacitors also have a certain service life, which will affect the use of the entire system

Method used

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  • Three-phase PWM rectifier DC bus capacitor current reconstruction and capacity identification method
  • Three-phase PWM rectifier DC bus capacitor current reconstruction and capacity identification method
  • Three-phase PWM rectifier DC bus capacitor current reconstruction and capacity identification method

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Embodiment 1

[0033] In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for reconfiguring the DC bus capacitor current of a three-phase PWM rectifier and identifying the capacity, the method comprising the following steps:

[0034] 1. After the on-board charging system is connected to the three-phase power grid, it first works in the state of uncontrolled rectification. This method does not need to add an additional current sensor on the DC side, and only needs the data of the three-phase voltage, current and DC bus voltage on the grid side to be obtained by the PWM rectification itself. According to the active power balance between the input side and the output side, the active power of the input side is calculated according to the voltage and current of the input side. The DC component of the rectifier DC side current can be obtained from the active power of the output side and the DC side voltage through a low-pa...

Embodiment 2

[0038] Combine below Figure 1-Figure 5 1. The specific calculation formula further introduces the scheme in Embodiment 1, see the following description for details:

[0039] After the on-board charging system is connected to the power grid, it first runs in the state of uncontrolled rectification, without adding additional sensors, and uses the existing voltage and current sampling to reconstruct the capacitor current, such as image 3 , and perform parameter identification.

[0040] Depend on figure 1 As shown in the structure, in the three-phase uncontrolled rectifier circuit, according to the instantaneous power conservation at the input and output sides:

[0041] p in =p out +p loss (1)

[0042] Among them, p in ,p out ,p loss Respectively, the AC input instantaneous power of the rectifier, the instantaneous output power of the DC side of the rectifier, and the instantaneous power loss.

[0043] and:

[0044] p in =e a i a +e b i b +e c i c (2)

[0045]...

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Abstract

The invention discloses a three-phase PWM rectifier DC bus capacitor current reconstruction and capacity identification method. The method comprises the steps of obtaining input side active power according to input side and output side active power balance and input side voltage and current, and obtaining a direct current component of rectifier direct current side current from the output side active power and the direct current side voltage through a low-pass filter; subtracting the direct-current component from the ratio of the input side active power to the input side direct-current voltageto obtain capacitance current; discretizing a charging and discharging equation of the capacitor according to a first-order Euler method, and identifying the capacity of a capacitor based on a least square method. According to the invention, under the condition that the direct-current side load is unknown and no extra sensor is added, the direct-current bus capacitance current is reconstructed andthe capacitor capacity is identified, so that the parameter design of the control system is completed, and rectification operation of PWM is started.

Description

technical field [0001] The invention relates to the field of topology and control technology of power electronics technology, in particular to a three-phase PWM rectifier DC bus capacitor current reconstruction and capacity identification method. Background technique [0002] The development of the traditional automobile industry has brought great convenience to people's travel, but with the continuous increase of the per capita car ownership in the world, the excessive use of fossil energy such as coal and oil, environmental pollution, energy crisis and resource shortage are becoming more and more serious. . As an environment-friendly vehicle, new energy vehicles use renewable energy as the power source and can achieve clean and zero-pollution emission operation. Under the background of the transformation of the world's energy structure, new energy vehicles have received widespread attention. Electric vehicle charging technology has also become a research hotspot. The DC ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J7/10H02J7/00B60L53/62
CPCH02J7/06H02J7/00712H02J7/0071B60L53/62Y02T10/70Y02T10/7072Y02T90/12Y02T10/72
Inventor 张云姚川恒
Owner TIANJIN UNIV
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