A motor insulation and short-circuit identification method for frequency converter
An identification method and frequency converter technology, applied in short-circuit test, motor generator test, emergency protection circuit device, etc., can solve problems such as inability to operate, narrow short-circuit current wave width, small output voltage, etc., and achieve small damage and reduced destructive power Small, early protective effect
Active Publication Date: 2021-05-28
TAIAN TECH WUXI
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Problems solved by technology
However, the output voltage is small at low frequency, and the PWM pulse width is very small. When the output is short-circuited, the short-circuit current has a very narrow wave width, which will be filtered by the RC of the over-current detection circuit and cannot operate, which will cause immediate damage to the IGBT.
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[0034] In order to make the object, technical solution and advantages of the present invention clearer, the implementation manner of the present invention will be further described in detail below in conjunction with the accompanying drawings.
[0035] figure 1 It shows the structure of a typical three-phase power inverter, where Vu, Vv, Vw are the voltages output to the three-phase star winding, V DC is the input voltage of the inverter, the six switches can be BJT or GTO or IGBT, the turn-on sequence of the switches must comply with the following conditions:
[0036] 1. Three of the switches remain on, and the other three switches remain off;
[0037] 2. The up and down switches of the same phase are driven by 2 complementary pulse signals; in this case, the up and down switches are not allowed to be turned on at the same time to ensure that the power supply V DC Will not short circuit.
[0038] Motor failures fall into two categories:
[0039] 1. The upper and lower arm...
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The invention discloses a motor insulation and short-circuit identification method for a frequency converter, which belongs to the field of motor control. In this method, before the motor runs, the CPU of the frequency converter outputs an adjustable PWM signal according to the timing diagram, and first identifies whether the upper and lower arms are short-circuited. Carrier interruption only changes the conduction state once, even if there is an abnormality in the inverter and the motor, the damage caused is small; it solves the problem that the inverter and the motor will be damaged when the motor is short-circuited; Short circuit and insulation identification can protect the motor and frequency converter earlier, so that the destructive force caused by short circuit faults can be reduced.
Description
technical field [0001] The embodiments of the present invention relate to the field of motor control, in particular to a motor insulation and short circuit identification method for a frequency converter. Background technique [0002] After the insulation layer between two adjacent wires in the motor winding is damaged, the two wires touch each other, which is called winding short circuit. A winding short circuit that occurs in the same winding is called an inter-turn short circuit; a winding short circuit that occurs between two phase windings is called a phase short circuit. No matter what kind of short circuit it is, it will increase the current of one or two phases of the motor, cause local heating, and cause the insulation layer to age and damage the motor. Therefore, it must be shut down immediately after a short circuit occurs. [0003] Generally, the frequency converter that drives the motor will have an over-current (OC) detection circuit. However, the over-curren...
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IPC IPC(8): G01R31/52G01R31/34H02H7/085
CPCG01R31/34G01R31/346H02H7/085G01R31/50
Inventor 任梦蕊
Owner TAIAN TECH WUXI