Single-phase electronic type electric energy meter electric source

Abstract

The invention relates to a single-phase electronic type electric energy meter electric source which comprises an industrial frequency transformer T1, a rectification circuit D1, a filter circuit C1, a sampling control circuit, a switch circuit SW1, a voltage reduction DC / DC circuit and a voltage booster DC / DC circuit, wherein industrial frequency AC Vin reduces voltage through the industrial frequency transformer T1 and then obtains an DC voltage end V1 through the rectification circuit D1 and the filter circuit C1; the V1 end is directly connected with an input end of the voltage reduction DC / DC circuit; the voltage reduction DC / DC circuit outputs DC V2 to the voltage booster DC / DC circuit; an output end V3 of the voltage booster DC / DC circuit supplies a stable working electric source for a CPU and a metering chip of an electric energy meter; one end of the sampling control circuit is connected with the V1, and the other end is connected with a control end of the switch circuit SW1; and the input end and the output end of the switch circuit SW1 are respectively connected with the input end and the output end of the voltage reduction DC / DC circuit. The working performance of the electric source with the structure is stable, the production cost is low, and the working scope of an electric source meter can reach AC40 to 400V.

Description

technical field [0001] The invention belongs to the field of electronic measuring instrument manufacturing, and in particular relates to a single-phase electronic electric energy meter power supply. Background technique [0002] The power supply circuit of the existing single-phase electronic energy meter mostly adopts a power frequency transformer plus a linear voltage stabilizing circuit (such as figure 1 shown), the working range is between 85V-280. Because this kind of circuit does not use switching power supply, its work is relatively reliable, so this kind of circuit or similar circuits are widely used in single-phase electronic energy meters. However, this kind of circuit has high requirements on the power grid. The single-phase electronic energy meter of this circuit often fails to work, resulting in the loss of electricity bills. In order to overcome the above problems, one of the schemes is to adopt a switching power supply scheme, such as the patent number discl...

AI Technical Summary

Problems solved by technology

Because this kind of circuit does not use switching power supply, its work is relatively reliable, so this kind of circuit or similar circuits are widely used in single-phase electronic energy meters. However, this kind of circuit has high requirements on the power grid. The single-phase electronic energy meter of this circuit often fails to work, resulting in the loss of electricity bills

In order to overcome the above problems, one of the schemes is to adopt a switching power supply scheme, such as the patent number disclosed in the Chinese utility model patent: 02271250.X and the technical scheme named "switching power supply with a wide input voltage range". The circuit structure is mainly composed of a control chip, a transformer, an electronic switch, a start-up circuit of the control chip, a voltage feedback circuit, a rectification filter circuit, and a voltage stabilization circuit. The working range of the energy meter using this switching power supply has been expanded, but At low voltage, it is necessary to intermittently charge and discharge the capacitance of the starting circuit to make the control chip work, and then control the on-off of the electronic switch, so the reliability is reduced

The second solution is to improve the voltage stabilizing circuit. After the power frequency transformer is stepped down, the TPIC74100 chip is used for the subsequent voltage stabilizing. The technical realization is to use MOS tubes to switch the buck-boost topology. This circuit designs the working voltage of its electric energy meter. It can also achieve lower than 85V, but the TPIC74100 chip is expensive and not easy to promote

Images