Medium voltage motor soft start device for chiller

Abstract

The invention relates to a medium-voltage motor soft start device in a water chilling unit, belonging to the technical field of starting cabinets of water chilling units of central air-conditioners. The medium-voltage motor soft start device comprises a power conversion protection circuit, a current and voltage monitoring circuit, an executing circuit and a control circuit, wherein the control circuit is connected with the power conversion protection circuit, the current and voltage monitoring circuit and the executing circuit; the current and voltage monitoring circuit is connected with the power conversion protection circuit; the power conversion protection circuit is externally connected with a power input wire; and the executing circuit is externally connected with a motor M. The medium-voltage motor soft start device has the advantage of reducing the impact of the current generated when the motor M is started on a power grid; and meanwhile, a microcontroller U can be used for sampling voltage, current and leakage current of the circuit and providing detection protection for voltage, current and leakage current faults of the motor M, therefore starting protection and using safety of the motor M are achieved.

Description

technical field [0001] The invention belongs to the technical field of starting cabinets for central air-conditioning chillers, and in particular relates to a soft starter for medium-voltage motors of chillers. Background technique [0002] Large-scale air-conditioning chillers generally use medium-voltage motors (3-10KV) as power. The motors often require higher voltages and starting currents several times greater than the rated current when starting. The traditional method is to connect them in series in the main circuit of the motor Reactor, to reduce the voltage at start-up, or use autotransformer power supply to start, and then cut off the reactor and autotransformer respectively after startup. These two start-up methods have the following disadvantages: both operation and cut-off are impactful, which will cause a large harmonic impact on the medium-voltage motor, easily cause motor failure, and cause pollution to the power grid; there are many high-voltage equipment an...

AI Technical Summary

Problems solved by technology

These two start-up methods have the following disadvantages: both operation and removal are impactful, which will cause a large harmonic impact on the medium-voltage motor, easily cause motor failure, and cause pollution to the power grid; there are many high-voltage equipment and are reliable. Low performance, poor security, high investment cost; poor equipment versatility, inflexible startup

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