A frequency converter motor drive circuit and frequency converter

Abstract

The invention discloses a motor drive circuit of a frequency converter, which is applied to a frequency converter. The motor drive circuit comprises a rectifier module, a soft start module, a filter module, a control module and an inverter module which are sequentially connected. The motor drive circuit of the frequency converter further comprises a normally-open controllable switch additionally arranged between the filter module and the inverter module of the frequency converter, when the frequency converter is not electrified, the filter module is disconnected with the inverter module; when a right connection manner is that an RST (Radiosensitivity Testing) is electrified, the power supply is used for charging the filter capacitor module through the rectifier module; when the control circuit is started, the control module outputs a control signal to control the normally-open controllable switch to be closed, and the frequency converter can normally output; and when a power supply lead is connected to the output end of the frequency converter by mistake, a closed loop can not be formed through charging, the control part is always kept at a power losing state because the filter capacitor can not be charged, namely, a safety state, and thus smashing caused by wrong connection of the frequency converter can be effectively avoided, and the fault type loss is prevented. The invention further discloses a frequency converter.

Description

technical field [0001] The present invention relates to the technical field of motor drive, and more specifically, relates to a frequency converter motor drive circuit and a frequency converter. Background technique [0002] At present, frequency converters are mainly used in motor drives, which mainly realize AC-DC-AC conversion. The frequency converter includes rectification module, soft start module, filter module, control module and inverter module and other main modules. The input AC power is rectified into DC by the rectifier module, and the rectified voltage is converted into smooth DC voltage by the filter module, and then controlled The module controls the inverter module to convert DC to AC. The main function of the soft start module is to limit the current peak value of the filter capacitor when power is applied to protect the rectifier module from being damaged by a large charging current. However, when the inverter is used in the field, it may The power line wi...

AI Technical Summary

Problems solved by technology

The frequency converter includes rectification module, soft start module, filter module, control module and inverter module and other main modules. The input AC power is rectified into DC by the rectifier module, and the rectified voltage is converted into smooth DC voltage by the filter module, and then controlled The module controls the inverter module to convert DC to AC. The main function of the soft start module is to limit the current peak value of the filter capacitor when power is applied to protect the rectifier module from being damaged by a large charging current. However, when the inverter is used in the field, it may The power line will be wrongly connected to the output terminal of the inverter module, and the power supply can also be rectified by the diode in the inverter module to charge the filter module when power is turned on. However, there is no current limiting of the soft start circuit at the inverter module end protection, it will cause the inverter module to withstand a large charging current and be damaged. Even if the inverter module is not damaged, running the inverter at this time may cause a dangerous accident of short circuit explosion

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