Frequency converter low voltage ride through power supply control system

Abstract

The invention discloses a frequency converter low voltage ride through power supply control system, which comprises a power supply module, an execution module and a monitoring module, wherein when themonitoring module detects that the variable-frequency direct-current bus voltage of the frequency converter is lower than a low-voltage ride-through voltage threshold value, the monitoring module controls the execution module to be connected with a circuit in connection with the variable-frequency direct-current bus, and the power supply module is used for conducting direct-current power supply on the variable-frequency direct-current bus through the execution module; when the monitoring module detects that the voltage of the variable-frequency direct-current bus is not lower than a low-voltage ride through voltage threshold value, the monitoring module controls the execution module to be disconnected with the circuit in connection with the variable-frequency direct-current bus, and the power supply module stops direct-current power supply to the variable-frequency direct-current bus; the power supply module comprises a storage battery set for conducting direct-current power supply onthe variable-frequency direct-current bus and a charging unit for charging the storage battery pack; the charging unit charges the storage battery pack through a first positive pole bus and a first negative pole bus corresponding to the first positive pole bus; and the charging unit is provided with a floating charging function.

Description

technical field [0001] The invention belongs to the field of electric power guarantee equipment design, and in particular relates to a low-voltage ride-through power supply control system for a frequency converter. Background technique [0002] In recent years, with the rapid development of power electronics technology and the increasing demand for energy saving in thermal power plants, frequency converters have gradually replaced traditional speed control devices in thermal power plants due to their advantages in soft start, variable frequency speed regulation, and complete protection functions. It is widely used in power plant auxiliary machines, and design units are increasingly inclined to adopt frequency converter technology in the design of many thermal power plant auxiliary machines. However, most frequency converters have poor low-voltage ride-through capability, or even do not have this capability. When the power system is disturbed, the low-voltage protection func...

AI Technical Summary

Problems solved by technology

However, the voltage drop of the power grid usually lasts for a short time and the voltage drop is large. If the voltage drop reaches more than 50% during low voltage ride-through, the inverter will trip at low voltage, so it is necessary to install a set to maintain the normal operation of the inverter. Device for low voltage ride through time