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Power converter

A power conversion device and a technology for power converters are applied to output power conversion devices, electrical components, and AC power input is converted into DC power output, etc. Effects of Harmonic Components

Active Publication Date: 2009-11-18
HITACHI POWER SEMICON DEVICE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The components in the audible range become electromagnetic noise and become harsh noise. In addition, if the frequency component of the AC current matches the resonance frequency of the mechanical system, excessive vibration will occur, which may cause malfunction of the device.

Method used

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Experimental program
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Effect test

no. 1 approach

[0031] use figure 1 A structural diagram of the first embodiment of the present invention will be described. figure 1 The power conversion device 100 includes: a DC power supply 1, a smoothing capacitor 2 connected in parallel, a power converter main circuit section (power converter circuit section) 3 that applies a voltage across the smoothing capacitor 2 to the input side through a shunt resistor 5, An AC motor 4 connected to the AC output of the power converter 3 , a rotor position sensor 12 attached to the AC motor 4 to output a rotor angle signal θ, and a microcomputer 8 .

[0032] The microcomputer 8 has the following functions: the current detection unit 6 inputs the DC bus current IDC flowing in the shunt resistor 5, and reproduces the phase currents Iuc, Ivc, and Iwc; the voltage command value generation unit 7 inputs the reproduced phase currents Iuc, Ivc , Iwc and any externally applied current command value Id * ,Iq * , output the first voltage command value Vu ...

no. 2 approach

[0090] use Figure 5 A structural diagram of the second embodiment of the present invention will be described. exist Figure 5 In the power conversion device 110 , the configuration of the power conversion device 100 according to the first embodiment is omitted, and the rotor position estimation unit 10 for estimating the rotor position of the AC motor 4 is added instead of the rotor position sensor.

[0091] The rotor position estimation calculation unit 10 receives the reproduced currents Iuc, Ivc, and Iwc obtained by reproducing the motor currents Iu, Iv, and Iw as input, performs estimation calculation of the rotor position, and outputs a phase signal θc of the estimated rotor position. The rotor position estimation calculation uses the first voltage command value Vu * 、Vv * 、Vw * , internal resistance and inductance of the AC motor 4 and other motor constant values ​​for calculation. The voltage command generation unit 7 acquires the phase signal θc of the estimated ...

no. 3 approach

[0093] use Figure 6 A configuration diagram of a third embodiment of the present invention will be described. exist Figure 6 In the power conversion device 120, the speed control unit 11 is added to the configuration of the power conversion device 110 according to the second embodiment to constitute a speed control system. The speed control unit 11 uses the output of the rotor position estimation operation unit 10, that is, the speed estimated value ωc and the arbitrarily applied speed command value ω1 * As input, output the d-axis current command value Id * and the q-axis current command value Iq * . The estimated speed value ωc is a differential value of the phase signal θc of the estimated rotor position calculated by the rotor position estimated calculation unit 10 . The speed control unit 11 compares the speed command value ω1 * and the estimated speed value ωc, thereby performing speed control.

[0094] In addition, in the case of constituting a speed control sy...

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PUM

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Abstract

The invention provides a power converter comprises a pipelined burst mode (PBM) control unit (9) for comparing a three-phase alternating current signal (Vum*, Vvm*, Vwm*) and a triangular wave carrier signal for producing a pulse-width modulated wave. A power converter circuit (3) drives a switching device by the pulse-width modulated wave for converting a direct current into the three phase alternating current. A current detector unit (5, 6) detects a direct current bus current at a direct current input of the power converter circuit for reconstructing a phase current. The power converter further comprises a voltage order changing part (8). Three odd unit periods take as a voltage order changing period. The unit period is a period of increasing or reducing the triangular wave carrier signals, a correction signal whose mean value being 0 or almost 0 in the voltage order changing period is added to the three-phase alternating current signal. Thus, a direct bus current can be detected precisely and an upper harmonics component is inhabited.

Description

[0001] The present invention is a divisional application of the application number 200710186499.x filed by the applicant Hitachi Manufacturing Co., Ltd. on November 22, 2007, and the title of the invention is "power conversion device". technical field [0002] The present invention relates to a power conversion device that detects a DC bus current to obtain current information on an AC side. Background technique [0003] In a power conversion device such as an inverter or a converter, the function of DC-AC conversion or AC-DC conversion is realized by pulse width modulation (hereinafter referred to as "PWM"). Inverters are used in driving systems of AC motors (hereinafter referred to as "motors") such as synchronous motors and induction motors, and converters are widely used as power supply devices such as inverters. [0004] When the motor is driven by the inverter, in order to control the torque generated by the motor with high precision, it is necessary to extract only th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/48H02P27/08
CPCH02M7/53871H02M7/5395H02M1/0009
Inventor 青柳滋久岩路善尚坂本洁户张和明
Owner HITACHI POWER SEMICON DEVICE