What failures will variable frequency power supply cause to other equipment? how to prevent
change of frequencies Power supplies are primarily used for testing and debugging of imported and exported electrical products as well as power supplies for precision instruments, which are widely used in the production of domestic appliances, electronic goods, IT equipment, and other items, among other things. However, the setup and operation of a variable frequency power supply will have an impact on and occasionally even create problems with other system components. What particular forms are there? What safety measures ought to be taken?
Regarding the electricity supply's high-order harmonics. Since almost all variable frequency power supplies use PWM (Pulse Width Modulation) control mode, this type of modulation will produce higher harmonic currents on the power supply side, resulting in voltage fluctuations when the variable frequency power supply operates and distorts the voltage waveform. distortion of the waveform that has negative consequences.
To avoid this, we suggest that you employ the following strategy: The variable frequency power source should be powered by a unique transformer that is isolated from other power systems. To lower high-order harmonic components, add a filter inductor or numerous rectifier bridge circuits to the variable frequency power supply's input side. A choke coil must be connected in series upstream of the capacitor to reduce harmonic components, and the inductance of the choke coil must be accurately analyzed and calculated to prevent the formation of inductance and capacitive oscillations. High-order harmonic currents will increase the capacitor current and produce a lot of heat for phase capacitors.
Query regarding the operating range and engine overheating. The cooling capacity of self-cooling motors will be decreased during low-speed operation, resulting in the motor overheating, if some companies retrofit existing motors with frequency conversion and speed control. Additionally, the output waveform of the variable frequency power supply contains high-order harmonics that will raise the motor's iron and copper losses. Therefore, it is advised to take the following actions after verifying the motor's state of charge and working range: increasing the motor's specification level, using a separate motor for frequency conversion, limiting the working range, and avoiding low-speed areas.
Regarding the impact of high-frequency switching's highest voltages on the insulation of motors. Particularly in the case of variable frequency PWM control power supplies, the output voltage of the variable frequency power supply includes high-frequency overvoltage, and these high-order harmonic pulse voltages will reduce the insulation resistance of the motor winding. The actions listed below can be taken: Reduce the wiring distance between the motor and the variable frequency power source. To handle the output voltage of the variable frequency power supply, use blocking diodes to reduce the surge voltage. For variable frequency power supplies, consider adding filtering on the motor input device.
