Zero-current switched-off solid state relay

Abstract

The invention relates to a zero-current switched-off solid state relay, which comprises a power voltage zero-crossing pulse generation circuit, a switching-off pulse generation circuit, an external control switch signal circuit, a switch master control circuit and a switch transistor circuit, wherein the output end of the power voltage zero-crossing pulse generation circuit is electrically connected with the voltage signal input end of the switch master control circuit; the output end of the switching-off pulse generation circuit is electrically connected with the switching-off signal input end of the switch master control circuit; the output end of the external control switch signal circuit is electrically connected with the control signal input end of the switch master control circuit; and the control signal output end of the switch master control circuit is electrically connected with the input end of the switch transistor circuit. The solid state relay can be switched on in the zero-crossing of a power voltage and switched off in the zero-crossing of a load current, avoids relatively more intensive impact to a switch at the moment of switching a circuit on and off, protects the switch and prolongs the service life of the switch.

Description

Technical field [0001] The invention relates to a zero-current turn-off solid-state relay. The solid-state relay includes a power supply voltage zero-crossing pulse generating circuit, a turn-off pulse generating circuit, an external control switch signal circuit, a switch main control circuit, and a switch transistor circuit. The solid state relay power supply Turns on when the voltage crosses zero, and turns off when the load current crosses zero. technical background [0002] Solid state relays (SSR), also known as solid state relays, are a new type of non-contact electronic switching device composed of electronic components developed by the combination of modern microelectronics technology and power electronic technology , It uses the switching characteristics of electronic components to achieve the purpose of making and breaking the circuit without contact and spark. The relay is a four-terminal device, including two input terminals and two output terminals. The input termi...

AI Technical Summary

Problems solved by technology

However, for capacitive loads or inductive loads, if the power supply switch adopts a random single-phase AC solid state relay, it may catch up with the power supply voltage being at a non-zero high value when it is turned on, which will cause a large impact on the load. The charging current of the capacitive load; although switching to a zero-crossing single-phase AC solid state relay can solve the current impact problem of the capacitive load when it is turned on, it is in the process of disconnecting the capacitive load or inductive load when the power supply voltage crosses zero. Near the maximum value of the current, it will cause a large current impact or overvoltage to the solid state relay, which will reduce its service life and even damage related components

Therefore, it is necessary to provide a new zero-current turn-off solid-state relay, which is used to overcome the problem that the circuit with capacitive load or inductive load has a large current impact or overvoltage on the solid-state relay when it is turned off.

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