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Chapter 2 Product Information
If the device designed is a 10kV frequency-controlled system, it contains 8 power units in each
phase.
By using an optimised PWM (Pulse Width Modulation) control technology with independent
intellectual property rights, the voltage waveform output to the motor is very close to a sinusoidal
waveform with low harmonic content and small dv/dt. No additional filters are required and the
output can be directly to an asynchronous motor or a synchronous motor with no requirement for
the length of the cable from the AC drive to the motor. Communication between the power unit and
the control cabinet is via high-speed and reliable optical fibre, which effectively avoids
electromagnetic interference and increases the reliability of the system.
3) Control cabinet composition:
The control cabinet is the core of the whole high voltage variable frequency speed control
system, it decides and controls the action of each power unit according to the user's operation and
setting locally or remotely, and collects the voltage and current analogue quantities in the system,
and each switching quantity, after logic processing and calculation, to further drive the motor and
meet the output requirements.
The control cabinet includes isolation transformers, low voltage devices, the whole control
board, IO board, fibre optic board and LCD operating human-machine interface. Of these, all
calculations are carried out in the DSP control board. The control core is a professionally designed
DSP (Digital Signal Processor) supplemented by FPGA (Field Programmable Gate Array), their use
not only allows for high speed calculations and complex control functions, but also greatly
simplifies the design of the control circuit and improves the reliability of the control system.
4) Bypass cabinet:
The bypass cabinet is optional. Without the bypass cabinet, the high voltage input and output
lines can be connected via terminals in the transformer cabinet.
If bypass cabinets are used, either manual bypass or automatic bypass can be selected and the
corresponding bypass cabinets are described as follows:
i.
Manual bypass cabinets:
The bypass cabinet in manual bypass mode is mainly composed of isolation knife gate, its
main function is to provide high voltage power supply for high voltage motors directly from the
grid when the high voltage AC drive is overhauled, without affecting the user's use. When in use,
it can be switched between AC drive operation and industrial frequency operation.
ACH200 Series High Voltage Variable Frequency Speed Control System Operating Manual
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