Product overview principle and characteristics Model definition and selection description Technical parameters Primary plan

　　working principle:

　　The high-voltage variable frequency soft starter is composed of a phase-shifting transformer, 24/10KV (15/6KV) single-phase H-bridge inverters (three-phase input and single-phase output power units) and a control system. The outputs are connected in series to achieve 10KV (6KV) medium voltage output.

　　• The phase-shifting transformer is used to transform the primary side high voltage into multiple sets of secondary side voltages required by each power unit, and at the same time realize the phase shift and electrical isolation of the primary side and the secondary side line voltage, and reduce the primary side harmonics. The secondary winding of the phase-shifting transformer generally adopts the extended-side delta connection. There is a fixed phase difference between the windings, forming a multi-pulse rectification method, so that the harmonic currents of the windings on the secondary side of the transformer (that is, the power unit input) cancel each other out. It is not reflected to the primary side, which significantly improves the current waveform on the grid side and eliminates the harmonic pollution of the high-voltage variable frequency soft starter to the grid.

　　• The output side voltage of the high-voltage variable frequency soft starter is formed by the output voltage of each power unit in series. The power units are divided into three groups. Each group consists of the same number of power units connected in series into one phase (6kV 5 power units per phase, 10kV 8 power units per phase). The output of each power unit is a constant-amplitude PWM voltage waveform, and the output of each unit has a certain phase offset between each other. After series superposition, a sinusoidal stepped PWM waveform is formed on the output side of the high-voltage variable frequency soft starter.

　　• The switching frequency of each power unit can be lower, but the equivalent switching frequency of the output side voltage of the high-voltage variable frequency soft starter is higher, which greatly reduces the high-order harmonics output by the high-voltage variable frequency soft starter. According to the designed carrier PWM control algorithm, the control system controls the inverter output of each power unit in a timely manner to obtain an AC output voltage with adjustable frequency and amplitude to realize the variable frequency soft start control of the motor.

　　characteristic:

　　The key components are high-quality components from well-known international manufacturers, and the high-standard component derating design is implemented to make the equipment more reliable.

　　The patented transformer can use the control power supply to charge the power unit through the transformer's own windings, reducing the impact on the transformer when closing. It is more reliable than some brands that use high-voltage pre-charge or an external transformer/voltage regulator design.

　　Three-level redundancy of control power supply. One control power supply comes from a high-voltage power supply circuit, which is more reliable than the ordinary solution that uses two low-voltage circuits and UPS power supply for the control power supply, ensuring uninterrupted operation of the inverter. Even when the control power supply and high voltage are powered off at the same time, the small backup battery (or super capacitor) protects the inverter from losing control, and the system is safer. The small backup battery (or super capacitor) is simpler and easier to maintain than UPS.

　　can adapt to harsh input voltage fluctuations, and can work within the input voltage range of -45% to +15%. Some brands can only guarantee normal operation when the input voltage drops by 30%.

　　It has the function of non-stop during instantaneous power failure. In the event of instantaneous voltage drop or power failure of the input power, the inverter will not stop. Immediately after the power supply voltage is restored, accelerate again and return to the original state.

　　Unique heat dissipation and dustproof design, the power unit overheating protection setting value is up to 100℃, and the maximum working environment temperature can reach 55℃.

　　The main circuit is designed with large capacity, which can reach 150% overload capacity.

　　The main control system adopts a three-core control structure, which is faster in calculation speed, stronger in anti-interference ability, and more reliable than using PLC as logic.

　　The main control board adopts an 8-layer PCB board design, which has better noise immunity than the 4-layer main control board.

　　The main control and power unit use plastic optical fiber for communication, which is more flexible and more reliable than ordinary glass optical fiber.

　　has perfect protection functions such as overvoltage, overcurrent, overload, overtemperature, underload, etc. Some protection enable and protection action points are open to users, and users can set according to actual needs. Provide 8 user-defined fault protection

　　Passed the CE certification and the "National Electric Control and Distribution Equipment Quality Supervision and Inspection Center" 10kV/1000kW and above capacity output high-voltage inverter type test

　　With speed sensorless/speed sensor control mode, torque control can be realized, torque control and closed-loop control switching can be realized, making the starting and braking of the inverter more stable and reliable.

　　High control accuracy, speed control accuracy can reach 0.05%, speed adjustment range 1:100, torque response less than 150ms, torque control accuracy ±3%.

　　can achieve obstacle-free fast start, the acceleration curve can be set to S acceleration and deceleration.

　　With DC braking and excitation braking functions, it can quickly achieve braking and stop quickly and accurately.

　　can automatically identify motor parameters.

　　Built-in closed loop control (PID) function.

　　The input current is a sine wave, which meets the limit standard of higher harmonic current output specified by IEEE-519 (1992), without input filtering.

　　The power factor is greater than 0.95, no power compensation is required.

　　Through space vector sum injecting harmonic components, the utilization rate of DC voltage is improved and the quality of output waveform is improved at the same time. The output is close to sine wave, without output filtering, and the output cable length is almost unlimited.

　　Professional transformer design, lower copper loss and iron loss, and the efficiency of the whole machine is as high as 97%.

　　With a debugging mode, when the high voltage input is not connected, 380V low voltage is used to increase the main power to 10kV/6kV through the auxiliary winding of the input phase-shifting transformer to perform no-load debugging of the main power.

　　The powerful background debugging software can greatly shorten the debugging time.

　　The output terminal is programmable, which can easily realize the functions required by the user

　　Large color touch screen, Chinese screen, simple and quick operation, clear running status at a glance.

　　Through the field bus option, the user can easily realize the computer automation monitoring and management at the equipment level and the factory level.

　　The control board adopts a plug-in frame structure

　　The power unit of the frequency converter is a modular design, all units can be interchanged, and a drawer type structure is adopted

　　Fault self-diagnosis function, convenient and quick fault location

Comprehensive technical index of 6kV high voltage variable frequency soft starter

Comprehensive technical index of 10kV high voltage variable frequency soft starter