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power conversion device

A power conversion device and circuit technology, applied in the direction of output power conversion devices, electrical components, AC power input conversion to DC power output, etc., can solve the problems of discontinuous tone color changes and unrecorded changes, and achieve the purpose of suppressing rapid changes Effect

Active Publication Date: 2019-06-18
MITSUBISHI ELECTRIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this patent document 1, various problems that occur when switching the control mode of the inverter, specifically, the switching frequency becomes discontinuous, and the tone color change of the magnetic noise that occurs along with it becomes harsh, Problems such as fluctuations in the generated torque of the motor have been proposed, and techniques for solving these problems have not been described.

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0045] figure 1 It is a figure showing the structure of the power conversion apparatus in Embodiment 1. As shown in the figure, the power conversion device according to Embodiment 1 is configured to drive an AC motor 1 as a load by including an inverter circuit 2 , a DC voltage source unit 3 , a carrier generation unit 5 , The modulated wave generation unit 6 and the converted signal generation unit 4 of the comparison unit 7 , the modulation coefficient calculation unit 8 , the modulation mode selection unit 9 , the voltage detection unit 10 , and the AC voltage command generation unit 11 .

[0046] The inverter circuit 2 includes semiconductor switching elements (not shown), and has a function of converting the DC power supplied from the DC voltage source 3 into AC power of variable voltage and variable frequency, and supplying the power to the AC motor 1. The voltage detection unit 10 detects the DC voltage value output from the DC voltage source unit 3 and outputs it to t...

Embodiment approach 2

[0115] In Embodiment 1, in figure 2 In the relationship between the selection ranges of each modulation mode shown, the lower limit value PMF_1 of the modulation coefficient range of the overmodulation PWM mode in the selection area (2) is set to 0.9069, and in the range of modulation coefficients lower than this value, Select the non-synchronous PWM mode for zone (1). In contrast, in Embodiment 2, as Figure 9 As shown in the region (2)a, in the region where the modulation factor PMF is PMF_1 or less, the region where the modulation factor PMF satisfies PMF_0* A mode of the so-called synchronous PWM method of a synchronous strobe signal.

[0116] In Embodiment 2, the overmodulated PWM carrier generation unit 50b and the overmodulated PWM modulated wave generation unit 60b respectively execute the following processes. In addition, as an example of the carrier wave and the modulation wave respectively output by the overmodulation PWM use carrier generation part 50b and the o...

Embodiment approach 3

[0125] In Embodiments 1 and 2, a method based on Equation (1.3) was shown as the modulated wave calculated by the modulated wave generation unit 6, but the same can be achieved even in the method based on the modulated wave shown in Equation (1.2). Structure. In this case, it should be noted that the upper limit of the modulation coefficient that can be output by comparison with the usual triangular wave carrier, that is, the lower limit value PMF_1 of the modulation coefficient range that the overmodulation PWM mode in the region (2) is responsible for is lower than that of Embodiment 1, 2 and smaller values ​​(see Table 4 below).

[0126] (Table 4) Modulation wave calculation formula and overmodulation PWM mode switching modulation coefficient PMF_1

[0127]

[0128] In addition, the signals calculated by the overmodulated PWM modulation wave generator 60b at this time are as shown in Table 5 below.

[0129] (Table 5) Calculation signal (U phase) of the overmodulation P...

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Abstract

A power converter fixes, in one cycle of an alternating-current voltage output command, a gate pulse signal to always output a direct-current input positive side terminal voltage value of an inverter circuit in a period X1 centering on a phase angle θ1 for higher potential, fixes a gate pulse signal to always output a direct-current input negative side terminal voltage value of the inverter circuit in a period X2 centering on a phase angle θ2 for lower potential, and outputs a gate pulse signal in which a ratio of a period Y1, which is obtained by excluding the periods X1 and X2 from a period between the phase angle θ1 and the phase angle θ2, and the first period X1, and a ratio of a period Y2, which is obtained by excluding the periods X1 and X2 from a period between the phase angle θ2 and a phase angle θ1+360 [deg].

Description

technical field [0001] The present invention relates to power conversion devices. Background technique [0002] As a conventional document describing power conversion control, there is Patent Document 1, for example. In this patent document 1, various problems that occur when switching the control mode of the inverter, specifically, the switching frequency becomes discontinuous, and the tone color change of the magnetic noise that occurs along with it becomes harsh, A point where fluctuations occur in the generated torque of the electric motor and the like have been proposed as problems, and techniques for solving these problems are not described. [0003] In addition to this Patent Document 1, the following Patent Documents 2 to 4 and Non-Patent Documents 1 and 2 are also well-known documents related to power conversion control, and these documents are appropriately referred to in the embodiments described later as necessary. [0004] Patent Document 1: Japanese Patent No...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/5395H02P27/00
CPCH02M7/5395H02P27/00
Inventor 山崎尚德加藤将冈田万基横堤良
Owner MITSUBISHI ELECTRIC CORP