Circulating current control method and device for parallel power converters

A power conversion device and circulation control technology, which is applied in the direction of AC motor control, output power conversion device, AC power input conversion to DC power output, etc., can solve PWM switch signal inconsistency, large circulating current, and carrier signal phase difference becomes large and other problems, to achieve the direct effect of circulation suppression effect

Active Publication Date: 2014-12-17
SHANGHAI MITSUBISHI ELEVATOR CO LTD
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Problems solved by technology

However, when the number of parallel power converters in the parallel power converter device is too large, the method based on the same clock signal will not be able to cope with the resource limitation of the PWM port of the controller; the bus mode, communication mode, etc. need to add a synchronization line (synchronization line), Communication lines, etc., and when the synchronization line and communication line receive interference, it is easy to cause the phase difference between the carrier signals to become larger, which in turn leads to a large circulation
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  • Circulating current control method and device for parallel power converters
  • Circulating current control method and device for parallel power converters
  • Circulating current control method and device for parallel power converters

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Embodiment 1

[0063] Such as figure 1 As shown, the parallel power conversion system includes two parts, the parallel power conversion device and the control device of the parallel power conversion device, wherein the parallel power conversion device further includes 1# inverter and 2# inverter connected in parallel, a DC power supply, 1# current detector and 2# current detector; each inverter is controlled by the control device of the parallel power conversion device; the control device of the parallel power conversion device further includes a current command generator (here, a speed controller) , current controller, circulating current calculator, circulating current controller, modulation signal generator, PWM unit, and carrier signal generator; the same polarity terminals on the DC side of 1# inverter and 2# inverter are connected to the DC The corresponding phases of the AC side of the 1# inverter and the 2# inverter are connected in series through the respective reactors L 1 , L 2 ...

Embodiment 2

[0118] Such as figure 2 As shown, this embodiment is similar to Embodiment 1, the only difference is that the circulating current controller and the modulation signal generator are omitted, and the output of the current controller is sent to the PWM unit as a modulation signal, and the rest are the same as Embodiment 1.

[0119] The method that the phase adjuster adjusts the phase of the carrier signal output by the carrier signal generator includes the following steps:

[0120] Step 1: The circulating current calculator calculates the circulating current value at time k according to the current value at time k;

[0121] Step 2: The circulation size calculator calculates the size of the circulation at time k according to the circulation value at time k;

[0122] Step 3: The phase adjuster uses the phase shift to adjust the phase of the carrier signal at time k;

[0123] Step 4: The circulation calculator calculates the circulation value at k+g time according to the current ...

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Abstract

The invention discloses a circulating current control method for parallel power converters. The method includes the steps of 1, calculating magnitude of circulating current of k moment according to a circulating current value of the k moment; 2, adjusting a phase position of a k moment carrier signal according to a phase shift; 3, calculating magnitude of circulating current of k+g (g>/=1) moment according to a circulating current value of the k+g moment; 4, determining changes in the magnitude of the circulating current before and after phase adjustment; 5, adjusting the phase position of a k+g (g>/=1) moment carrier signal according to the changes in the magnitude of the circulating current. The method has the advantages that circulating current caused by a phase difference among PWM (pulse width modulation) carrier signals of power converters in a parallel power conversion system can be suppressed effectively and reliably, the limitation on the quantity of the parallel power converters in parallel power conversion equipment is avoided, and circulating current suppression is convenient to implement. The invention further discloses a control device employing the circulating current control method for parallel power converters.

Description

technical field [0001] The invention relates to the field of power conversion device control, in particular to a method for controlling the circulation of a parallel power converter device composed of a plurality of power converters. The invention also relates to a control device for a parallel power conversion device. Background technique [0002] The parallel connection technology of power conversion devices is an important technical means to expand the power of power conversion devices, improve reliability, and realize flexible adjustment of power conversion device power. Circulating current is a problem that must be solved for parallel power conversion devices, which makes circulating current control technology the key and core of parallel technology for power conversion devices. Chinese invention patent CN200810166314.3 (application date: 2008.09.19) proposes to control the circulating current by using the sum of the positive and negative bus voltage difference and the...

Claims

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Application Information

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IPC IPC(8): H02M7/5387H02P27/06
Inventor 陈玉东钱敏刘玉兵何晓光贺东方
Owner SHANGHAI MITSUBISHI ELEVATOR CO LTD
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