Frequency conversion unit used for alternating current contactor

Abstract

A frequency conversion unit for an AC contactor, characterized in that: the frequency conversion unit is a four-port network, which consists of a first input terminal (N1), a voltage-controlled switch circuit, a first output terminal (P1), an energy storage The circuit, the second output terminal (P2), and the second input terminal (N2) are sequentially connected in series; the first input terminal (N1) and the second input terminal (N2) of the frequency conversion unit are respectively connected with the first AC voltage Terminal (S1) and second terminal (S2) are connected, and the first output terminal (P1) and second output terminal (P2) are respectively connected to the first terminal (A1) and the second terminal (A1) of the exciting coil (L) in the AC contactor. The two terminals (A2) are connected; the second output terminal (P2) of the frequency conversion unit, one terminal of the energy storage circuit, the second terminal (A2) of the exciting coil (L) and the second input terminal (N2) Also connected to common (E).

Description

technical field [0001] The invention relates to the field of low-voltage electrical appliances, in particular to a frequency conversion unit adopted in a frequency conversion type power-saving AC contactor which adopts frequency conversion technology and has the function of saving electric energy. Background technique [0002] AC contactor is a low-voltage electrical appliance that is widely used. Its working principle is to use the electromagnet to drive the moving contact (moving contact) and the static contact (moving contact) to close or separate, so as to achieve the purpose of connecting or cutting off the circuit. It is suitable for starting or controlling three-phase induction motors and other electrical equipment. [0003] figure 1 It is the working principle diagram of the traditional AC contactor. This traditional AC contactor is mainly composed of a moving iron core, a static iron core, an exciting coil, a return spring, a moving-break contact, and a moving-cl...

AI Technical Summary

Problems solved by technology

[0010]1. Unnecessary power consumption: As mentioned above, in the pull-in and hold stages, the excitation coils of traditional AC contactors are connected with "the same "AC voltage makes the holding power too large, resulting in unnecessary power loss;

[0011]2. Heating: The result of unnecessary power loss is "heating and heating". In severe cases, it will even burn the excitation coil of the traditional AC contactor;

[0012] 3. Low power factor: There is an inevitable exchange of electric energy between the excitation coil of the traditional AC contactor and the excitation power supply, resulting in a The power factor is only about 0.5;

[0016]1. The structure is complex and difficult to implement;

[0017]2. Too many electronic devices are used, and the electronic circuit is too complicated; the "AC contactor power saver" controlled by a single-chip microcomputer is easily affected by the AC contactor itself or the motor, etc. The electromagnetic interference of electrical appliances leads to internal program execution errors and "flying jump" miscontrols. This miscontrol will lead to catastrophe in some occasions!

[0018]3. The price of the products produced is too high. For example, the price of the QXJB AC contactor power saver produced by a company in Zhuhai City, Guangdong Province is as high as 1,500 yuan / tower! The price of a small AC contactor is only more than 20 yuan, and the price of a medium-sized AC contactor is only a few hundred yuan. Such an expensive "QXJB AC contactor power saver" will make very few users

[0019]4. Due to the complexity of the electronic circuit and the many electronic devices used, it is difficult to integrate the power-saving control part of the AC contactor with the AC contactor. The power-saving control part of the system requires another box, which causes inconvenience for users to install and troublesome wiring.

The main reason is that the price of energy-saving contactors is relatively expensive, and users cannot accept the one-time investment. It is necessary for the country to increase policy efforts in the promotion of energy-saving contactors to promote the wide application of energy-saving contactors" (reference 1: Qian Jinchuan et al., Summary of AC Contactor Energy Saving Technology, China Electronics Business, Issue 4, 2011)

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