Power supply for use in an electronic energy meter
First Claim
1. A power supply for use in an electronic electricity meter operable to receive and monitor a three-phase line voltage, the power supply comprising:
- a voltage rectifier positioned to receive the line voltage and generate a DC bus voltage;
a transformer having a primary winding and a secondary winding, wherein the DC bus voltage is applied to the primary winding such that current flows through the primary winding, wherein the primary winding discharges to the secondary winding to define an output voltage of the power supply;
a switch connected to the primary winding for selectively permitting and preventing the flow of current through the primary winding, wherein when the current is prevented from flowing through the primary winding, the primary winding discharges to the secondary winding;
a control circuit coupled to the switch to provide a control signal to the switch to control the operation of the switch between an on and an off position;
an over voltage circuit positioned to receive the DC bus voltage and coupled to the control circuit, wherein the over voltage circuit is operable to generate an over voltage signal to prevent the flow of current through the primary winding when the DC bus voltage exceeds an upper voltage limit.
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Accused Products
Abstract
A three-phase electronic electricity meter that includes a power supply circuit operable to create a constant voltage output when receiving a variable voltage input. The power supply circuit of the electricity meter receives a three-phase line voltage and converts the variable three phase line voltage to a constant DC output. The power supply circuit includes a current limiting circuit to suspend operation of the power converter when the current exceeds a selected value. The power supply circuit includes an over voltage protection that limits the maximum voltage applied to the switching component of the power supply circuit. Both the over voltage protection circuit and the current limiting circuit suspend operation of the power converter to prevent damage to the operating components of the power supply circuit.
57 Citations
20 Claims
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1. A power supply for use in an electronic electricity meter operable to receive and monitor a three-phase line voltage, the power supply comprising:
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a voltage rectifier positioned to receive the line voltage and generate a DC bus voltage;
a transformer having a primary winding and a secondary winding, wherein the DC bus voltage is applied to the primary winding such that current flows through the primary winding, wherein the primary winding discharges to the secondary winding to define an output voltage of the power supply;
a switch connected to the primary winding for selectively permitting and preventing the flow of current through the primary winding, wherein when the current is prevented from flowing through the primary winding, the primary winding discharges to the secondary winding;
a control circuit coupled to the switch to provide a control signal to the switch to control the operation of the switch between an on and an off position;
an over voltage circuit positioned to receive the DC bus voltage and coupled to the control circuit, wherein the over voltage circuit is operable to generate an over voltage signal to prevent the flow of current through the primary winding when the DC bus voltage exceeds an upper voltage limit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A power supply for use in an electronic electricity meter operable to receive and monitor a three-phase line voltage, the power supply comprising:
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a voltage rectifier positioned to receive the line voltage and generate a DC bus voltage;
a transformer having a primary winding and a secondary winding, wherein the DC bus voltage is applied to the primary winding such that current flows through the primary winding, wherein the primary winding discharges to the secondary winding to define an output voltage of the power supply;
a switch connected to the primary winding for selectively permitting and preventing the flow of current through the primary winding, wherein when the current is prevented from flowing through the primary winding, the primary winding discharges to the secondary winding; and
a control circuit coupled to the switch to provide a control signal to the switch to control the operation of the switch between an on and an off position, wherein the control signal generated by the control circuit is a periodic signal having repeating pulses each separated by an off time, each pulse having an on time duration, wherein the on time duration is determined based upon the value of the DC bus voltage. - View Dependent Claims (13, 14, 15, 16, 17)
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18. The method for supplying power to the operating components of an electronic electricity meter that meters electrical energy, the energy having a variable line voltage, the method comprising the steps of:
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rectifying the line voltage to generate a DC bus voltage;
providing a transformer having a primary winding and a secondary winding;
providing the DC bus voltage to the primary winding of the transformer;
providing a switch that selectively permits and prevents a flow of current through the primary winding, wherein the primary winding discharges to the secondary winding upon the prevention of current flow through the primary winding;
providing a control circuit that controls the operation of the switch;
comparing the value of the DC bus voltage to an upper voltage limit and generating an over voltage signal to the control circuit when the DC bus voltage exceeds the upper voltage limit; and
operating the control circuit to prevent the flow of current through the primary winding upon receipt of the over voltage signal at the control circuit. - View Dependent Claims (19, 20)
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Specification