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Power inversion device and control method thereof

A technology of power conversion device and control method, which is applied in the direction of output power conversion device, conversion of AC power input to DC power output, control system, etc.

Inactive Publication Date: 2011-01-26
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0011] On the other hand, in patent documents 2 to 5, although it is possible to output PWM pulses equivalent to the conventional 3-phase modulation method, it may cause malfunction , further research is required to ensure stable operation during practical application
In addition, depending on the magnitude of the voltage command value, multiple simultaneous switching operations may occur, resulting in electromagnetic wave interference.

Method used

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  • Power inversion device and control method thereof
  • Power inversion device and control method thereof
  • Power inversion device and control method thereof

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Embodiment Construction

[0051] Embodiments of the present invention will be described below with reference to the drawings.

[0052] FIG. 1 is a schematic structural diagram of a main circuit and a control system of a power conversion device according to an embodiment of the present invention. As the main circuit, there is an inverter main circuit part 1 composed of switching elements and an AC motor 2 as a load, which is supplied with variable voltage and variable frequency alternating current from the main circuit 1 and powered by the main circuit 1 drive. The control system is composed of a computing device 3 and a drive circuit 4. The computing device 3 computes a signal for driving the main circuit part 1, so that the load 2 performs a desired action. The output signal drives the main circuit part 1 . The calculation device 3 is constituted by a calculation processing device such as a microcomputer or an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit)....

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Abstract

The invention provides a power converting device. The device can maintain the coequal wave characteristic as the current three-phase modulating way in the low-speed area of the loading electric motor 2, achieving the stable driving to reduce the electromagnetic wave. The independently-arranged U-W phase triangular wave generates the potion 6u-6w; and generating the triangular load independently to enable the triangular waves of the phases has the difference of the phase position. In addition, the micro computer is used as the operating device 3; in order to compare the voltage instruction value of the phases Vu*=Vw* to the triangular waves, using the timing buffer 9u-9w for different phases to process the temporary setting action; and adjusting the frequency of the signal carrier of each phase alone according to the information of output voltage and acceleration of the power converter and so on to drive the switch by outputting the way that the change of PWM pulse of the voltage whichcan not be eclipsed.

Description

technical field [0001] The present invention relates to a power conversion device and a control method thereof, in particular to a power conversion device capable of reducing electromagnetic noise generated by a power converter and a control method thereof. Background technique [0002] The electromagnetic wave interference (EMI: Electromagnetic interference) generated by the power converter will bring adverse effects to the surrounding equipment, and cause the equipment to malfunction. As a countermeasure against this, it is common to install passive components such as common mode choke coils, but this leads to an increase in size and cost of the device. Electromagnetic wave interference becomes particularly noticeable when the load motor is driven at an extremely low speed, that is, when the output voltage amplitude of the power converter is close to zero. The reason is that at this time, almost all the switching elements of the three-phase inverter are turned ON / OFF at t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/5387H02P27/08
Inventor 绫野秀树稻叶博美大昭直人森和久蛭田清玄
Owner HITACHI LTD