Current control method used for high-voltage transducer

A high-voltage inverter and current control technology, which is applied in the four-quadrant motor control, AC motor control, control system, etc., can solve the problems of low-frequency operation torque ripple, high-frequency operation torque mutation, and affecting the mechanical life of the motor, etc. , to achieve stable and accurate detection of current, smooth and stable torque changes, and accurate and reliable detection results

Inactive Publication Date: 2011-04-27
RONGXIN POWER ELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] At present, in the control process of the four-quadrant high-voltage inverter, there are generally situations such as low-frequency operation torque ripple and high-frequency operation torque mutation, which seriously affect the operation stability of the control object such as the hoist.
At the same time, the sudden change of torque seriously affects the mechanical life of the motor, causing potential safety hazards

Method used

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  • Current control method used for high-voltage transducer
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  • Current control method used for high-voltage transducer

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Experimental program
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Effect test

Embodiment 1

[0039] A current control method for high-voltage frequency converters, which uses the Clarke transformation principle to obtain accurate instantaneous current effective values, and changes the output voltage of the high-voltage frequency converter by changing the PWM working state of the power unit to automatically adjust the output current of the motor , quickly and stably control the motor output torque.

[0040] The method of calculating the instantaneous current RMS value through the principle of Clarke transformation is:

[0041] Let S be the variable to be transformed, then the transformation relationship from three-phase coordinates to two-phase coordinates is established as follows:

[0042]

[0043] Among them, S 0 is the zero-sequence component and can be ignored.

[0044] Let θ=0, then the q-axis and the a-axis coincide; ignoring the zero-sequence component, the formula (1) is simplified as

[0045] S q = ...

Embodiment 2

[0063] The method of calculating the effective value of the instantaneous current by the principle of Clarke transformation in Embodiment 1 can also be used to detect the effective value of the current of the fans and pumps driven by the high-voltage frequency converter.

[0064]In the past, the current RMS detection method is to perform root-mean-square processing on the sampled value of one cycle, and the calculated current RMS will lag behind one cycle, and the real-time performance is poor, and the current control is not ideal.

[0065] The invention adopts the principle of clarke transformation, only needs to obtain the real-time three-phase current from the sensor, can calculate the effective value of the instantaneous current, and realize the instantaneous detection of the current. Therefore, the problems of slow current detection and unsatisfactory current control are solved.

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Abstract

The invention relates to a current control method used for a high-voltage transducer. In the method, an accurate instantaneous current effective value is obtained through a Clarke transform principle, and the output voltage of the high-voltage transducer is changed and the output current of a motor is automatically regulated and the output torque of the motor is rapidly and stably controlled through changing the PWM (Pulse Width Modulation) working state of a power unit. The method can be used for accurately and rapidly measuring the instantaneous current value, and changing the voltage of the motor and stably controlling the output torque of the motor through controlling the PWM waveform output of the power unit, thereby realizing the function of rapidly and accurately controlling the torque by the high-voltage transducer at a frequency of 0-50HZ, especially at a low speed.

Description

technical field [0001] The invention relates to a current control method for a four-quadrant high-voltage frequency converter. Background technique [0002] Four-quadrant high-voltage inverters are used in hoisting machines and other fields that require precise control of current, especially when starting at low speed and high torque, smooth control of torque is required. At low speed, the rotor frequency is very low, and the current is close to DC. In order to achieve precise control at low speed, it is very important to quickly and accurately identify the magnitude of the current. In order to realize the fast and smooth control of the torque of the motor, it is necessary to change the output frequency and voltage at the same time, and there is a strict time limit requirement for the given quantity. [0003] At present, in the control process of the four-quadrant high-voltage inverter, there are generally situations such as low-frequency operation torque ripple and high-fr...

Claims

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Application Information

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IPC IPC(8): H02P23/06H02P27/04
CPCH02P21/0035H02P21/22
Inventor 胡涛杨洋李太峰赵淑玉王振郭自勇李旷李兴丁雅丽
Owner RONGXIN POWER ELECTRONICS
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