Discrete frequency conversion soft start method and soft starter

A discrete frequency conversion and soft start technology, applied in the field of soft start, can solve the problems that soft start methods and soft starters cannot adapt to the special environment in the mine

Pending Publication Date: 2018-12-07
XIAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Due to the complex and changeable environment in the mine, the general soft start method and soft starter cannot adapt to the special environment in the mine, which brings a lot of inconvenience to the underground operation

Method used

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  • Discrete frequency conversion soft start method and soft starter
  • Discrete frequency conversion soft start method and soft starter
  • Discrete frequency conversion soft start method and soft starter

Examples

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Comparison scheme
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Embodiment Construction

[0090] Such as figure 1 As shown, the discrete frequency conversion soft start method of the present invention comprises the following steps:

[0091] Step 1. Set the sub-frequency band of the start-up process as Slope voltage soft start and f seven bands; and set sub-bands The start-up time threshold is t 1 , set the sub-band The start-up time threshold is t 2 , set the sub-band The start-up time threshold is t 3 , set the sub-band The start-up time threshold is t 4 , set the sub-band The start-up time threshold is t 5 , set the startup time threshold of ramp voltage soft start to t 6 ; Wherein, f is the frequency and the value is 50Hz;

[0092] Step 2. Determine whether the startup time has reached the sub-band The start-up time threshold t 1 , and satisfy t 1 %(0.02×13)=0; when the start time reaches the sub-band The start-up time threshold t 1 , and satisfy t 1 When %(0.02×13)=0, perform frequency division triggering by 13; otherwise, continue to j...

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Abstract

The invention discloses a discrete frequency conversion soft start method and a soft starter, and the soft start method comprises the following steps: in a first step, frequency sub-bands of start processes and a start time threshold value are set; in a second step, a frequency sub-band f / 13 is started; in a third step, a frequency sub-band f / 7 is started; in a fourth step, a frequency sub-band f / 4 is started; in a fifth step, a frequency sub-band f / 3 is started; in a sixth step, a frequency sub-band f / 2 is started; in a seventh step, ramp voltage soft start is conducted; in an eighth step, start is completed; the soft starter comprises a microcontroller, an intrinsically safe power module, a liquid crystal touch screen and a communication module; an input end of the microcontroller is connected with a current detecting module, a voltage detecting module, an insulation resistance detecting circuit, a first thyristor detecting circuit, and a second thyristor detecting circuit, a third thyristor detecting circuit and a phase sequence detection module; an output end of the microcontroller is connected with an alarm device, a relay circuit and a drive circuit. The method and the soft starter disclosed in the invention can be used for realizing perfect transition from all sub-frequencies to power frequency, and that the motor can obtain large starting torque under a heavy load to achieve smooth start can be ensured.

Description

technical field [0001] The invention belongs to the technical field of soft start, and in particular relates to a discrete frequency conversion soft start method and a soft starter. Background technique [0002] With the continuous development of power electronic devices and the continuous maturity of modern control theory and technology, high-power devices such as thyristors, MOSFTs, GTOs and IGBTs are widely used in different fields, and the control method of soft start has emerged as the times require. Soft start is a motor starting method that reduces voltage without reducing frequency. Compared with the indirect starting method, its voltage change is continuous, so there is no secondary current impact in electronic soft start, and the torque change is relatively stable. But the electronic soft starter is not perfect: for ramp voltage, due to the motor When the starting angle is larger, the corresponding initial voltage is smaller, and the electromagnetic torque will b...

Claims

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Application Information

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IPC IPC(8): H02P1/30
CPCH02P1/30
Inventor 童军刘莉君乔健伟樊甜
Owner XIAN UNIV OF SCI & TECH
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