Apparatus for metering at least one type of electrical power over a predetermined range of service voltages

• US 7,180,282 B2
• Filed: 07/11/2003
• Issued: 02/20/2007
• Est. Priority Date: 02/21/1992
• Status: Expired due to Fees

• Current Assignee: Elster Electricity LLC (Honeywell International Inc.)
• Original Assignee: Elster Electricity LLC (Honeywell International Inc.)
• Inventors: Schleifer, Fred F.
• Primary Examiner(s): TANG, MINH NHUT
• Application Number:
  US10/617,844
• Publication Number:
  US 20040105206A1
• Time in Patent Office: 1,320 Days
• Field of Search: 323/220, 323/229, 323/231, 323/232, 323/247, 323/259, 323/299, 323/301, 323/304, 323/305, 323/355, 323/358, 323/359, 323/361, 323/363, 324/141, 324/142
• US Class Current: 324/142
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 21/1331 Measuring real or reactive component, measuring apparent energy
• CPC Class Codes: H02M 3/335 using semiconductor devices only
• CPC Class Codes: H02M 3/33507 with automatic control of the output voltage or current, e.g. flyback converters H02M3/33561, H02M3/33569 take precedence

Abstract

Methods and apparatus for supplying power for use in metering electrical energy over a wide range of voltages with a single meter are disclosed. The wide ranging meter includes a processing unit for processing divided input voltage and a current component in order to determine electrical energy metering values. The processing unit is operable in response to supply voltages. A power supply, connected to receive the undivided voltage component, generates the supply voltages over the wide dynamic range. It is especially preferred for the power supply to include a transformer having first, second and third windings, wherein the undivided voltage component is provided to the first winding and wherein the second winding defines the output of the power supply. A switching member is connected to the first winding for permitting and preventing the flow of current in response to a control signal. A control member generates the control signal in response to the output of the power supply. It is also preferred for the control signal to disable the witch member. It is further preferred for the power supply to include a voltage blocking clamp, connected to the transformer for blocking the voltage applied to the transformer. It is still further preferred for an oscillator to be used to generate an oscillating signal for switching the switching member ON and OFF so that the switching member is provided a substantially constant OFF time.

Claims

1. An electric energy meter for measuring electrical energy usage over a wide dynamic range of standard service voltages, wherein the electrical energy meter is used by an electric utility for customer billing purposes, and wherein the electrical energy meter can be connected to a polyphase electrical service to measure electrical energy on more than one phase, the meter having a power supply comprising:

a transformer having first, second, and third windings, the power supply being capable of receiving any input voltage within the wide dynamic range of standard service voltages, which input voltage is provided to the first winding so that current flows through the first winding, wherein a voltage across the second winding defines an output of the power supply, wherein a voltage across the third winding defines a sense signal that is representative of the output of the power supply, and wherein the output is regulated based at least in part on the sense signal to provide a predetermined output voltage independent of the input voltage, and wherein the wide range of service voltages include RMS voltages between about 96 Vrms and about 528 Vrms.

2. The electric energy meter of claim 1, wherein the third winding is substantially similar to the second winding, so the voltage across the third winding is similar to the voltage across the second winding.

3. The electric energy meter of claim 2, further comprising:

a switching member connected to the first winding;

a controller connected to the switching member and to the third winding, wherein the controller receives the sense signal from the third winding and sends a control signal to the switching member based on the sense signal, and wherein the control signal opens and closes the switching member to permit and prevent a flow of current to the first winding and to regulate the output of the power supply on the second winding.

4. The electric energy meter of claim 3, wherein the control signal operates to disable the switch means.

5. The electric energy meter of claim 3, wherein the switching means comprises a first transistor, connected between the first winding and ground, and wherein the control means comprises an oscillator, connected to the base of the transistor, for generating an oscillating signal for switching the transistor on and off, wherein the control signal causes the output of the oscillator to disable the first transistor.

6. The electric energy meter of claim 5, wherein the first transistor comprises a 600 volt MOSFET device.

7. The electric energy meter of claim 5, wherein the oscillator comprises a ring oscillator.

8. The electric energy meter of claim 3, wherein the control means comprises an over current protection detector and a means for voltage protection control.

9. The electric energy meter of claim 8, wherein the control signal is generated in response to an output of one of the over current protection detector and the means for voltage protection control.

10. The electric energy meter of claim 3, further comprising voltage clamping means, connected to the transformer and the switch means, wherein the input voltage is applied to the voltage clamping means, for limiting the voltage applied to the transformer.

11. The electric energy meter of claim 10, wherein the clamping means comprises first and second transistors and biasing means, connected to the first and second transistors, wherein the biasing means biases the first and second transistors so that the voltage provided by the clamping means does not exceed a desired level.

12. The electric energy meter of claim 11, wherein the clamping means disables the switch means when the input voltage exceeds the desired level.

13. The electric energy meter of claim 1, further comprising a charge means, connected to the second winding, for storing an electrical charge when current is flowing through the first winding and for discharging stored electrical charge when current flowing through the first winding is interrupted.