Switching power circuit for power supply of three-phase electric energy meter

Abstract

The invention discloses a switching power circuit for power supply of a three-phase electric energy meter. The switching power circuit comprises an EMI (electromagnetic interference) unit, a rectifier filter unit, a high-frequency transformer, a PWM (pulse width modulation) control unit, a sampling unit, a rectifier output filter unit and a constant voltage output unit, an output end of the EMI unit is connected with an input end of the rectifier filter unit, an output end of the rectifier filter unit is connected with an input end of the high-frequency transformer, a first output end of the high-frequency transformer is connected with an input end of the rectifier output filter unit, a second output end of the high-frequency transformer is connected with an input end of the constant voltage output unit, an output end of the constant voltage output unit is connected with an input end of the sampling unit, an output end of the sampling unit is connected with an input end of the PWM control unit, and an output end of the PWM control unit is connected with a controlled end of the high-frequency transformer. The high-frequency switching power circuit can supply two paths of independent 12V power for the three-phase electric energy meter, and has the advantages of high efficiency, wide input range, high stability, high reliability and the like as compared with a traditional linear power supply.

Description

technical field [0001] The invention relates to the field of electric energy meters, in particular to a switching power supply circuit for supplying power to three-phase electric energy meters. Background technique [0002] The existing three-phase watt-hour meters all use iron-core transformers to step down and then rectify and filter to supply power to the back-end circuit. Due to the large loss of the iron-core transformer, and the output fluctuates with the fluctuation of the input grid voltage, the requirements for the back-end circuit Higher, most of the methods require secondary voltage stabilization and other measures at the back end, which increases the difficulty of the circuit and reduces the reliability of the circuit, and also increases the cost of the circuit, and the circuit efficiency is not high and the utilization rate of electric energy is also low. In summary, the power supply circuit using iron core transformer will not be able to meet the current market...

AI Technical Summary

Problems solved by technology

[0002] The existing three-phase watt-hour meters all use iron-core transformers to step down and then rectify and filter to supply power to the back-end circuit. Due to the large loss of the iron-core transformer, and the output fluctuates with the fluctuation of the input grid voltage, the requirements for the back-end circuit Higher, most of the methods require secondary voltage stabilization and other measures at the back end, which increases the difficulty of the circuit and reduces the reliability of the circuit, and also increases the cost of the circuit, and the circuit efficiency is not high and the utilization rate of electric energy is also low. In summary, the power supply circuit using iron core transformer will not meet the current market and user requirements

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