Abstract : The output characteristics of a high-power variable frequency power supply under various loads (including purely resistive, inductive, capacitive, and nonlinear loads) were analyzed. Experimental results show that the output voltage and frequency of the power supply are very stable under various loads.
Keywords : frequency converter; output characteristics; waveform analysis
0 Introduction
As we all know, the mains power frequency we use is 50Hz. However, in real life, sometimes the required power frequency is not 50Hz, which necessitates a frequency converter. For a power supply, users expect it to output a stable voltage under various types of loads, and frequency converters are no exception. Therefore, it is necessary to study the output characteristics of frequency converters under various types of loads (purely resistive, inductive, capacitive, and nonlinear).
1 Experimental Design
The wiring diagram for this experiment is shown in Figure 1. The 50Hz three-phase grid voltage is rectified and inverted by the frequency converter to output a sine wave with a variable frequency (the user can adjust the output frequency). After LC filtering, it passes through a step-up transformer (its function is to step up the voltage and provide isolation) and is then applied to the three-phase load. The three-phase load can be purely resistive, inductive, capacitive, or nonlinear.
The desired result of this experiment is that when the output voltage and output frequency of the inverter are set to fixed values, this inverter power supply device can output stable voltage and frequency under various types of loads.
2. Parameter Selection
2.1 Frequency Converter
The frequency converter used in this experiment is the SIEMENS MIDIMASTERVECTOR (MDV), which has an output power of 7.5kW, a rated input voltage of 380V, an adjustable output voltage, an input frequency of 50Hz, and an adjustable output frequency.
For detailed information, please click: Output Characteristics and Experimental Analysis of High-Power Variable Frequency Power Supplies
