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power conversion device

A technology of power conversion device and control device, which is applied in the direction of output power conversion device, control of electromechanical transmission device, conversion of AC power input into DC power output, etc. Current detection value and other issues

Active Publication Date: 2020-09-22
MITSUBISHI ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] However, in the region where the amplitude of the above-mentioned voltage command value is large, each phase of the three phases is tentatively referred to as "maximum phase", "intermediate phase" in descending order of voltage command values ​​for each of the three phases. phase" and "minimum phase", the switching element of the lower arm of the largest phase is turned on for less than the time required for the current detector to detect the correct current detection value, therefore, the current detector cannot detect the largest phase accurate current detection value, it may not be possible to perform high-precision voltage control based on the above-mentioned current detection value

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Embodiment approach 1

[0110] figure 1 It is an overall configuration diagram of the power conversion device according to Embodiment 1 of the present invention. exist figure 1 Among them, the power conversion device according to Embodiment 1 of the present invention includes a three-phase inverter 3, a current detector 4, a filter capacitor 5, a basic command calculation unit 6, an offset voltage calculation unit 7a, and a corrected three-phase voltage command calculation unit. 8a and the phase current computing unit 9a. Here, the basic command calculation unit 6, the offset voltage calculation unit 7a, the corrected three-phase voltage command calculation unit 8a, and the phase current calculation unit 9a constitute a control device in the power conversion device, and the control device is a microcomputer operating based on a predetermined program. constitute.

[0111] The positive terminal and the negative terminal of the three-phase inverter 3 are connected to the positive side and the negativ...

Embodiment approach 2

[0206] Next, a power conversion device according to Embodiment 2 of the present invention will be described. The overall configuration diagram of the power conversion device according to Embodiment 2 of the present invention is the same as the above-mentioned figure 1 same. The power conversion device according to the second embodiment differs from the power conversion device according to the first embodiment in the configuration of the offset voltage calculation unit and the detection timing of the current detection value. In the following description, differences from Embodiment 1 will be mainly described.

[0207] Figure 8 It is a flowchart showing the calculation procedure of the offset voltage calculation unit in the power conversion device according to Embodiment 2 of the present invention. figure 1 The shown offset voltage calculation unit 7a calculates the offset voltage Voffset based on the U-phase voltage command Vub, the V-phase voltage command Vvb, and the W-ph...

Embodiment approach 3

[0216] Next, a power conversion device according to Embodiment 3 of the present invention will be described. The overall configuration diagram of the power conversion device according to Embodiment 3 of the present invention is the same as the above-mentioned figure 1 same. The power conversion device according to Embodiment 3 is different from the power conversion device according to Embodiment 2 in the detection timing of the current detection value and the configuration of the phase current calculation unit 9b. In the following description, differences from Embodiment 2 will be mainly described. Figure 11 It refers to the PWM carrier signal, the corrected three-phase voltage command, each switching element of the three-phase inverter, the U-phase lower arm switching element, and the V-phase upper arm switching element in the power conversion device according to the third embodiment of the present invention. An explanatory diagram for explaining the carrier cycle Tc.

[02...

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Abstract

The power conversion device of the present invention performs substantially equal offsets on the voltage commands of each phase, so that the voltage command of the largest phase is consistent with the maximum value of the PWM carrier signal, and compares it with the PWM carrier signal, so as to control the voltage and control the voltage. The current detection value corresponding to the phase in which the lower arm switching element is turned on is corrected based on the current detection value corresponding to the phase in which the upper arm switching element is turned on.

Description

technical field [0001] The present invention relates to a power conversion device composed of a three-phase voltage type inverter controlled by PWM. Background technique [0002] Generally, a power conversion device composed of a three-phase voltage source inverter controlled by PWM (Pulse Width Modulation: Pulse Width Modulation) is based on the output current value of each phase of the power conversion device detected by a current detector (hereinafter referred to as is the current detection value), to perform PWM control on / off of the switching elements respectively provided on the upper bridge arm and the lower bridge arm of each phase, so as to perform voltage control so as to follow the voltage command value. [0003] In the current detector described above, the reference potential common to each of the three phases is usually set to the ground potential. Therefore, the noise mixed in the current detection values ​​of the respective phases is often mixed with a compon...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/5387H02M1/08H02M7/5395H02P21/22H02M1/44H02P27/08
CPCH02M1/44H02M7/53871H02M7/5395H02P27/08H02P21/22H02M1/0009H02M7/53876H02M1/08
Inventor 森辰也古川晃
Owner MITSUBISHI ELECTRIC CORP