Variable frequency series resonance consists of a variable frequency power supply, an excitation transformer (also known as an excitation transformer), a reactor, and a capacitive voltage divider A voltage divider connected in parallel to the sample for measuring signals and resonant voltage for overvoltage protection; The FM excitation is coupled to a power output transformer in series with the resonant circuit, providing a series resonant excitation power. The test and detection device for frequency conversion series resonance structure is based on the working principle of knowledge series resonance. The excitation transformer can be used to excite the student series resonance control circuit, adjust the output signal frequency of the frequency conversion controller, and make the circuit inductance L and the test sample C resonate in series. The resonance voltage is the voltage applied to the test sample.
Advantages of series resonant transformer:
1. Series resonant power supply generates high voltage and high current by utilizing the resonance problem between the resonant reactor and the tested capacitor. In the entire management system, the power supply only needs to provide the active consumption part of the information system. Therefore, the power output power required for experimental development is generally only 1/Q
2. Greatly reduced the weight and volume of the equipment Series resonant power supply not only eliminates bulky power regulation devices and a common power frequency testing transformer, but also requires only 1/Q of resonant excitation power capacity testing, greatly reducing the weight and volume of the system, typically 1/5 of a general testing device of 1/3-.
3. Improve the waveform of the output working voltage of the enterprise. The resonant power supply circuit is a resonant filter in which the waveform distortion of the output voltage can be improved to obtain a good sine wave, effectively preventing the abuse of harmonic peak breakdown tests.
4. It will not cause any overvoltage without any recovery. When the sample malfunctions, due to the loss of resonance conditions, the high voltage immediately disappears, the arc can be extinguished, and the reconstruction process of restoring voltage is long. It is easy to disconnect the power supply before reaching the flash voltage again. The recovery process of this voltage is an intermittent oscillation process of energy accumulation, which takes a long time and will not cause overvoltage recovery.
5. Prevent short-circuit current burn points caused by faults. In the series resonance working state, when the weak point of the insulation of the test sample is broken down, the circuit can immediately de resonate, and the loop current rapidly decreases to 1/Q of the normal development test research current. Alternatively, when the parallel resonance voltage testing method is used to test the transformer, the breakdown current immediately rises several times, and the difference in breakdown current between the short-circuit current and the number of times is compared. So, series resonance can effectively identify a weak point in insulation, and there is no possibility of a large short-circuit calculation current burn at the fault point.
The frequency conversion resonance test device is widely used in industries such as power, metallurgy, petroleum, and chemical engineering. Suitable for switching and preventive testing of large capacity high-voltage capacitor test samples.