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Do you know the control method of series resonant inverter
2025-09-11Wuhan UHV specializes in producing series resonant devices (also known as series resonant). Next, we will share with you the control method of series resonant inverters. Do you knowWith the development of self turn off power electronic devices, series resonant inverter circuits have gained more and more applications, and various control methods suitable for series resonant inverter circuits continue to emerge. This article discusses and compares commonly used control methods such as amplitude modulation, pulse frequency modulation, pulse density modulation, and resonant pulse width modulation, and provides a detailed analysis of the control method of pulse width plus frequency modulation.Basic structure of inverterThe basic schematic diagram of an inverter includes a DC voltage source, an inverter bridge composed of switches S1-S4, and a series resonant load composed of R, L, and C. Switches S1-S4 can use power semiconductor devices with self turn off capabilities such as IGBT, SIT, MO
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Common troubleshooting methods for AC withstand voltage test devices
2025-09-11Common faults and solutions of series resonance (also known as AC withstand voltage test device):1、 The host cannot find the resonance point. Reason: The resonance point of the system is outside the output frequency range of the host; System wiring error; The system is not reliably grounded; High voltage sampling feedback signal open circuit or unreliable connection; The test sample has a malfunction. Exclusion method:1. Check the reliability of the grounding device and whether there are any disconnection points in the grounding connection wire; 2. Check the continuity of the high and low voltage coils of the excitation transformer; 3. Check the continuity of each reactor; 4. Check the continuity of the signal line of the voltage divider; 5. Check the continuity of the high and low voltage capacitor arms of the voltage divider;6. If there is no resonance point when the device is boosted, it is necessary to check the on/off of the compensation capacitor;2、 Host reset. Reason: Flu
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What is the principle of variable frequency series resonant device
2025-09-10Wuhan UHV specializes in producing series resonant devices (also known as variable frequency series resonant devices). Next, we will share with you the principle of variable frequency series resonant devices.Working principle of series resonance test device:A device that uses tuned inductors and load capacitors to generate power frequency series resonance and obtain power frequency test voltage. Composed of a variable frequency power supply, excitation transformer, reactor, and capacitive voltage divider. The capacitor and reactor of the test sample form a series resonant connection; The voltage divider is connected in parallel to the test sample to measure the resonant voltage on the test sample and provide an overvoltage protection signal; The frequency modulation power output is coupled to the series resonant circuit through an excitation transformer, providing excitation power for series resonance. The series resonance test device is a generation of equipment specifically designe
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What are the advantages of variable frequency series resonant voltage withstand device
2025-09-10Wuhan UHV specializes in producing series resonance (also known as variable frequency series resonance withstand voltage device). Next, we will share with you the advantages of variable frequency series resonance withstand voltage device.1. The required power capacity is greatly reduced. Series resonant power supply generates high voltage and high current through resonance between resonant reactor and the tested capacitor. In the entire system, the power supply only needs to provide the active consumption part of the system. Therefore, the required power supply for the experiment is only 1/Q of the test capacity.2. The weight and volume of the equipment have been greatly reduced. In a series resonant power supply, not only is the bulky high-power voltage regulating device and ordinary high-power power frequency test transformer eliminated, but the resonant excitation power supply only requires 1/Q of the test capacity, greatly reducing the system weight and volume, usually 1/10-1/30 of
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The principles of series resonance and parallel resonance, as well as the reasons for the large parallel resonance current
2025-09-10Wuhan UHV specializes in producing series resonance (also known as series resonance withstand voltage equipment). Next, we will share with you the principles of series resonance and parallel resonance, as well as the reasons for the large parallel resonance currentPrinciples of series resonance and parallel resonanceIn a series circuit of resistors, inductors, and capacitors, the phenomenon where the terminal voltage of the circuit is in phase with the total current of the circuit is called series resonance. A series resonant circuit is purely resistive, with terminal voltage and total current in phase. At this time, the impedance is small and the current is large, which may generate high voltages on the inductance and capacitance that are many times greater than the power supply voltage. Therefore, series resonance is also known as voltage resonance. In a circuit where an inductor is connected in parallel with a capacitor, the phenomenon of parallel resonance occurs where the termina
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Comprehensive knowledge explanation of series resonance
2025-09-09Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test equipment). Next, we will share comprehensive knowledge of series resonance with you.Application of series resonant deviceSeries resonance device is an important electrical indicator for insulation inspection of electrical equipment before operation, which is achieved through the principle of series circuit and constant voltage and current. For small capacity electrical equipment, we can use oil immersed test transformers for measurement. For large capacity electrical equipment, series resonance must be used, such as common power cables, transformers, and GIS combiners. Characteristics of series resonance device testDue to the fact that series resonance fully simulates the actual operating conditions of the power system, it is easier to directly and intuitively reflect the insulation situation of the equipment. Compared with using a DC high-voltage generator to check insulation, t
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13 characteristics of resonant devices
2025-09-09Wuhan UHV specializes in producing series resonators (also known as resonant devices). Next, we will share with you the 13 characteristics of resonant devices.Variable frequency series resonant devices typically have the following 13 characteristics:1. Voltage, current, time, status information and other data are displayed on a 4.7-inch large LCD screen, with clear and intuitive readings;2. Full Chinese interface, simple and clear operation, suitable for various application scenarios;3. The variable frequency series resonant device is operated by touch sensitive panel buttons, and all functions can be set through the buttons, improving the safety and reliability of the product; 4. The fully digital calibration method abandons the outdated potentiometer adjustment, making it extremely convenient for on-site use and easy to control accuracy (with password protection function);5. The button directly sets the voltage conversion ratio (with password protection function), and when connectin
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How to identify cable breakdown using cable withstand voltage testing equipment
2025-09-09Wuhan UHV specializes in producing series resonance (also known as cable withstand voltage test equipment). Next, we will share with you how cable withstand voltage test equipment can identify cable breakdown.Partial discharge and high-voltage testing of cables often lead to the phenomenon of cable breakdown; The reasons for the phenomenon of cable "breakdown" are not only the real breakdown caused by the quality management problems of cable enterprises themselves, but also some other important reasons for the false breakdown phenomenon of cables. So how can we judge the authenticity of cable breakdown? A manufacturer of variable frequency series resonant devices, shares with you some methods for identifying cable breakdown:1. Due to the fact that the partial discharge and high voltage environment tests of network cables are conducted one by one in the shielded room, when breakdown occurs, the enterprise can fully consider replacing the insulated wire core for retesting. If the wire co
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A comprehensive explanation of the AC withstand voltage test device for testing
2025-09-08Wuhan UHV specializes in producing series resonance (also known as AC withstand voltage test device). Next, we will share a comprehensive explanation of the AC withstand voltage test device for testing.Preparation work before GIS AC withstand voltage testGIS equipment should be debugged and qualified. After passing the insulation characteristic test, SF6 gas should be inspected at rated pressure. The TA secondary in the test circuit should be short circuited and grounded. The lightning arrester and protective spark gap in the test circuit should be disconnected from the tested GIS. Before the experiment, check whether the high-voltage cables and overhead lines, voltage transformers, lightning arresters, and high-voltage outgoing lines of power transformers are disconnected from the GIS before conducting the series resonant AC withstand voltage test. Series resonance test deviceConnect and check. During the experiment, if an isolation switch or tee is used to connect the detection slee
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What equipment is required for voltage withstand test
2025-09-08The function of voltage withstand testVoltage withstand test, also known as high voltage dielectric strength test, is one of the main methods for testing the ability of electrical appliances, electrical equipment, electrical devices, electrical circuits, and electrical safety equipment to withstand overvoltage. Voltage endurance is divided into two types: AC voltage endurance test and DC voltage endurance test. AC withstand voltage testAC withstand voltage refers to the highest voltage value that equipment can withstand when the voltage is positive or negative peak. The test voltage is more than one to several times the rated voltage of the tested equipment, and the AC voltage test equipment's withstand voltage is closer to the actual situation, without the need to gradually increase the voltage. From the perspective of thermal breakdown caused by dielectric loss, it can effectively discover local free defects and weak points of insulation aging. However, AC withstand voltage is m
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What should be paid attention to in the AC withstand voltage test
2025-09-05Wuhan UHV specializes in producing series resonance (also known as AC withstand voltage test equipment). Next, we will share with you what to pay attention to in AC withstand voltage testing.The AC withstand voltage test is conducted to check the insulation performance of electrical equipment by applying high voltage at the operating frequency. In the power system, such as transformer main withstand voltage test, AC withstand voltage test of power cables, insulation test of insulation equipment, etc., AC withstand voltage test can be conducted before power system debugging or regular inspection. So, what should be paid attention to when conducting AC withstand voltage test? We should pay attention to the following matters during the withstand voltage testBefore communicating the withstand voltage, the tested product should be wiped clean. If it is an oil filled device, letting the oil sit for a period of time to eliminate residual bubbles inside can effectively improve the pressure re
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Comprehensive Introduction to AC withstand voltage
2025-09-05Wuhan UHV specializes in producing series resonance (also known as AC withstand voltage test device), and now we will share a comprehensive introduction to AC withstand voltage with you.AC voltage withstand test is used to check the insulation performance of electrical equipment by applying high-frequency high voltage. AC voltage withstand test is a common item in power systems. So why not use DC voltage measurement? Below, we will briefly explain the significance of using AC voltage withstand test!Why not use DC withstand voltageCompared with DC voltage, the voltage, waveform, frequency, and electric field state inside the insulation of the tested object in AC testing are consistent with the actual operating conditions, and the test voltage is higher than the value of the internal overvoltage. Therefore, it can effectively detect the main insulation defects of electrical equipment, especially for the insulation defects of the stator winding slot, which is more effective than DC withst
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A comprehensive explanation of series resonance for you
2025-09-05A comprehensive explanation of series resonance (also known as variable frequency series resonance device) will be introduced to you. Firstly, whether it is series resonance or parallel resonance, they belong to the structural branches of series resonance testing devices, but there is a slight difference in their names. Next, let's take a detailed look.What is series resonanceWith the preventive testing of large capacity and high voltage electrical engineering equipment in China, it is recommended to use power frequency withstand voltage to analyze the performance of insulation materials, which eliminates the management requirements for insulation performance testing of electrical technology equipment using DC high-voltage generators. Although both belong to destructive tests, after long-term research by enterprises, the use of power frequency withstand voltage method has better stability and safety compared to DC withstand voltage. Due to the large capacity and high voltage of ele
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On site testing of series resonance test equipment
2025-09-04Wuhan UHV specializes in producing series resonance (also known as series resonance test equipment). Next, we will share with you the on-site testing of the series resonance test equipment.The variable frequency series resonance test device is a high-capacity high-voltage sample withstand voltage test equipment that adopts the principle of LCR series resonance circuit. For a high-voltage equipment enterprise such as a test transformer, there are strict technical development requirements in its application, but its completion time is generally limited by the test transformer, which cannot meet the high-voltage requirements of large capacity test samples. The inverter series vibration testing device generally consists of an inverter source, excitation variables, resistors (multiple), voltage molecules, and may also have compensating capacitors under special conditions. The on-site management and use of the variable frequency series resonance test device requires students to follow thei
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How to operate the power frequency withstand voltage test device
2025-09-04Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test device). Next, we will share with you how to operate the power frequency withstand voltage test device.Operation guide for power frequency withstand voltage test deviceBefore operating the system, we should grade it according to the capacity and voltage of different test samples, calculate the maximum operating current, and adjust the economic current protector. Power frequency withstand voltage test device1. Connect a power supply (box type refers to socket type power supply, desktop type refers to terminal type power supply), and automatically control the voltage reduction through a voltage regulator to zero position. The zero position switch is closed, and the zero position indicator light (red light) is on (also known as the zero position balance output working status of the voltage regulator can be indicated); 2. Press the start button (green light), the contactor draws in a
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Precautions for using variable frequency series resonant device
2025-09-04Wuhan UHV specializes in producing series resonance (also known as power frequency withstand voltage test equipment). Next, we will share with you the precautions for using variable frequency series resonance devices.The variable frequency series resonant device utilizes the principle of series resonance and the output characteristics of the excitation transformer to excite the series resonant circuit. By adjusting the output frequency of the variable frequency controller, the inductance L in the circuit resonates with the sample C. The resonant voltage is the voltage applied to the sample. On site inspection of the laying quality of cross-linked cables and the installation quality of accessories is an effective means. By connecting series and parallel reactors, the AC withstand voltage requirements of 10kV-500kV high-voltage cross-linked cables can be met.The variable frequency series resonant device is suitable for AC withstand voltage testing of various large power transformers, pow
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How to select a complete set of equipment for power frequency withstand voltage test
2025-09-03Wuhan UHV specializes in the production of series resonance (also known as power frequency withstand voltage test equipment). Next, we will share with you how to select the power frequency withstand voltage test equipment.Overview of Series Resonance Test DeviceThe series resonance test device is a series resonance test device that uses tuned inductors and load capacitors to generate power frequency series resonance and obtain power frequency test voltage. A resonant series is composed of isolation and transformer, frequency and voltage regulation system power supply, excitation for transformer, reactor, and capacitive voltage divider. The capacitors and resistors of the subjects form a series resonant connection, and the voltage molecules are connected in series with the main body to measure the resonant voltage on the main body and provide overvoltage protection signals. The frequency modulation power output is coupled with the excitation transformer and the series resonant circuit t
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Guidelines for Safe Operation of AC Withstand Voltage Test Equipment
2025-09-03Wuhan UHV specializes in producing series resonance (also known as AC withstand voltage test equipment). Next, we will share with you the safety operation guidelines for AC withstand voltage test equipment.1. It is not allowed to suddenly cut off the system power during testing. Before performing the series resonance test, the test state must be exited before the power can be cut off. 2. After the host malfunctions, do not open the chassis for maintenance, otherwise the consequences will be borne by yourself. 3. Do not store or use the instrument in high temperature, high humidity, flammable, explosive, or strong magnetic fields. 4. Use a damp cloth and neutral cleaning agent to clean the instrument casing for maintenance and upkeep. Do not use abrasives and solvents. 5. Before testing, please check whether the series resonant instrument is intact, whether the connecting wires are intact, ensure power output, whether the signal sampling cable is firmly connected, and whether the co
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The reason why the series resonance test equipment cannot be improved
2025-09-03Wuhan UHV specializes in producing series resonance (also known as series resonance test equipment). Next, we will share with you the reasons why series resonance test equipment cannot be improved.There are two main reasons why series resonance testing equipment does not boost voltage when understanding voltage. For example, whether the boost point did not rise after finding the resonance point, or whether the boost did not rise during the search for the resonance point. By analyzing these two situations, determine whether there is a problem with the series resonance testing device itself or whether the insulation of the test item is damaged.For example, the first scenario is damage to the cable insulation layer (this possibility is very small, and if it is damaged, the resonance point cannot be found).The second scenario is that the reactor you are using is damaged. This kind of hardware damage will definitely not increaseUsually, series resonance does not enhance. In most cases, prob
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Characteristics of Variable Frequency Series Resonant Device
2025-09-02Wuhan UHV specializes in producing series resonant devices (also known as variable frequency series resonant devices). Next, we will share with you the characteristics of variable frequency series resonant devices.The main characteristics of series resonance are:1. Easy to operate: Two modes of automatic testing (automatic search for resonance point and automatic boost) and manual testing (manual search for resonance point and manual boost) are suitable for different testing requirements. 2. Can set the test voltage, frequency range, protection current, and pressurization time.3. Automatic mode: only need to set the test voltage and time; Automatic precision of equipment Quasi frequency regulation and voltage regulation; Complete the experiment and save the data. 4. It has grounding and flashover protection functions. In the event of flashover of the test sample or sudden loss of resonance in the resonant circuit caused by other reasons, the variable frequency control power supply wi
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