Direct-current solid-state relay

Abstract

The invention discloses a solid-state relay. The solid-state relay comprises a direct current input positive terminal, a direct current input negative terminal, a direct current output positive terminal, a direct current output negative terminal, a control end positive terminal, a control end negative terminal, an isolating circuit, a driving circuit, a first switch, a second switch, a first diodeand a second diode. A dual-switch and dual-freewheel-diode cross connection way is adopted, energy stored in a load end line cannot be changed suddenly, and a novel path is found for continuous flowof current through freewheel diodes. The energy stored in the load-end line is fed back to a direct-current power grid through the path, thereby realizing lossless energy recovery of energy. Moreover,the product is small in size, low in cost and suitable for high-power occasions.

Description

technical field [0001] The invention relates to a solid state relay, in particular to a DC solid state relay. Background technique [0002] The schematic diagram of the existing solid state relay is as follows: figure 1 As shown, it consists of control terminal positive terminal K+ and control terminal negative terminal K-, load terminal positive terminal L+ and load negative terminal L-, shell 1, internal isolation circuit 2, drive circuit 3 and switch S. The isolation circuit 2 is used to isolate the low-voltage control terminal and the high-voltage load terminal, and the drive circuit 3 is used to amplify the weak control signal input from the low-voltage control terminal and provide it to the switch S to drive the high-current load at the load terminal. [0003] When the existing solid-state relay is disconnected, a very large peak voltage will be generated at both ends of the switch S. Therefore, it is necessary to connect an absorbing circuit 4 in parallel at both end...

AI Technical Summary

Problems solved by technology

[0006] (1) Part of the energy stored in the line at the load end is consumed by the heat generated by the resistor R, and the other part is stored and absorbed by the capacitor C. When the fault is eliminated, the switch S is turned on, and the capacitor C will discharge. The absorbing circuit 4 is a lossy absorption, not Conducive to the energy saving of the power system;

[0007] (2) When the energy stored in the load-side line is large, the RC is required to be large in size and high in cost, which is not suitable for medium and high-power solid-state relays

[0010] The above-mentioned high-voltage and high-current situations all require the application of high-power DC solid-state relays. There is no technical solution with small size, low cost and energy saving in the prior art.

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