CIRCUIT ARRANGEMENT FOR FILTERING AN ELECTRIC CURRENT

• US 20170237333A1
• Filed: 02/17/2016
• Published: 08/17/2017
• Est. Priority Date: 02/17/2016
• Status: Active Grant

• Current Assignee: City University of Hong Kong
• Original Assignee: City University of Hong Kong
• Inventors: Wang, Kewei, Chung, Shu Hung Henry
• Granted Patent: US 10,678,281 B2
• Time in Patent Office: Days
• CPC Class Codes: G05F 1/565 sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor G05F1/563 takes precedence
• CPC Class Codes: G05F 1/59 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/0045 Converters combining the concepts of switch-mode regulation and linear regulation, e.g. linear pre-regulator to switching converter, linear and switching converter in parallel, same converter or same transistor operating either in linear or switching mode
• CPC Class Codes: H02M 1/12 Arrangements for reducing harmonics from ac input or output
• CPC Class Codes: H02M 7/217 using semiconductor devices only

Abstract

A circuit arrangement for filtering an electric current, wherein the circuit arrangement is arranged between a power source providing the electric current and a load; and the electric current includes a first current component and a second current component. The circuit arrangement includes a first circuit arranged to receive and filter the first current component, a current control device arranged to receive and regulate the second current component so as to provide a regulated current to the load, and a control circuit arranged to provide a control signal to the current control device so as to control regulation of the second current component. The control circuit is further arranged to detect one or more operation parameters associated with the current control device, and to determine the control signal based on the one or more detected operation parameters.

Claims

1. A circuit arrangement for filtering an electric current, wherein the circuit arrangement is arranged between a power source providing the electric current and a load;

and the electric current includes a first current component and a second current component;

the circuit arrangement comprising;

a first circuit arranged to receive and filter the first current component;

a current control device arranged to receive and regulate the second current component so as to provide a regulated current to the load; and

a control circuit arranged to provide a control signal to the current control device so as to control regulation of the second current component;

wherein the control circuit is further arranged to detect one or more operation parameters associated with the current control device, and to determine the control signal based on the one or more detected operation parameters.

2. The circuit arrangement in accordance with claim 1, wherein the one or more operation parameters associated with the current control device comprises at least one of:

a voltage difference across the current control device, a magnitude of the second current component, and a frequency of the second current component.

3. The circuit arrangement in accordance with claim 1, wherein the control circuit comprises:

a voltage control circuit having

a voltage sensor arranged to detect a voltage difference across the current control device; and

a voltage controller arranged to compare the detected voltage difference with a reference voltage value so as to determine the control signal;

wherein the control signal is arranged to minimize a difference between the detected voltage difference and the reference voltage value.

4. The circuit arrangement in accordance with claim 3, wherein the voltage controller comprises an error amplifier.

5. The circuit arrangement in accordance with claim 3, wherein the voltage control circuit forms a closed loop.

6. The circuit arrangement in accordance with claim 3, wherein the reference voltage value is predetermined.

7. The circuit arrangement in accordance with claim 3, wherein the reference voltage value is dynamically adjustable.

8. The circuit arrangement in accordance with claim 1, wherein the control circuit comprises:

a current control circuit having

a current sensor arranged to detect the second current component or the regulated current; and

a current controller arranged to compare the detected current with a reference current value so as to determine the control signal;

wherein the control signal is arranged to minimize a difference between the detected current and the reference current value.

9. The circuit arrangement in accordance with claim 8, wherein the current controller comprises an error amplifier.

10. The circuit arrangement in accordance with claim 8, wherein the current control circuit is in the form of a closed loop.

11. The circuit arrangement in accordance with claim 8, wherein the reference current value is predetermined.

12. The circuit arrangement in accordance with claim 8, wherein the reference current value is dynamically adjustable.

13. The circuit arrangement in accordance with claim 1, wherein the control signal comprises a first control signal component and a second control signal component;

and

the control circuit comprises;

a voltage control circuit having

a voltage sensor arranged to detect a voltage difference across the current control device;

a voltage controller arranged to compare the detected voltage difference with a reference voltage value so as to determine the first control signal component; and

a current control circuit having

a current sensor arranged to detect the second current component or the regulated current; and

a current controller arranged to compare the detected current with a reference current value so as to determine the second control signal component;

wherein the first control signal component is arranged to minimize a difference between the detected voltage difference and the reference voltage value; and

wherein the second control signal component is arranged to minimize a difference between the detected current and the reference current value.

14. The circuit arrangement in accordance with claim 1, wherein the current control device is connected in series between the power source and the load.

15. The circuit arrangement in accordance with claim 14, wherein the current control device is an active circuit device.

16. The circuit arrangement in accordance with claim 14, wherein the current control device comprises a transistor.

17. The circuit arrangement in accordance with claim 16, wherein the transistor comprises a field effect transistor or a bipolar junction transistor.

18. The circuit arrangement in accordance with claim 17, wherein the transistor is a bipolar junction transistor, and the control signal is a base current of the bipolar junction transistor.

19. The circuit arrangement in accordance with claim 17, wherein the transistor is a field effect transistor, and the control signal is a gate-source voltage of the field effect transistor.

20. The circuit arrangement in accordance with claim 14, wherein the current control device comprises a transistor network with a plurality of transistors each arranged to receive a respective control signal from a control circuit.

21. The circuit arrangement in accordance with claim 20, wherein the plurality of transistors are connected in parallel.

22. The circuit arrangement in accordance with claim 20, wherein the plurality of transistors are connected in series.

23. The circuit arrangement in accordance with claim 14, wherein the first circuit is a shunt circuit connected across the power source.

24. The circuit arrangement in accordance with claim 23, wherein the shunt circuit is an active circuit.

25. The circuit arrangement in accordance with claim 23, wherein the shunt circuit is a passive circuit.

26. The circuit arrangement in accordance with claim 23, wherein the shunt circuit comprises a capacitor.

27. The circuit arrangement in accordance with claim 1, wherein the first current component contains or is an unwanted frequency component of the current;

and the second current component contains or is a wanted frequency component of the current.

28. The circuit arrangement in accordance with claim 1, wherein the second current component and the regulated current have substantially identical frequency content.

29. The circuit arrangement in accordance with claim 1, wherein the second current component and the regulated current have substantially identical magnitude.

30. A circuit arrangement for filtering an electric current, wherein the circuit arrangement is arranged between a power source providing the electric current and a load;

and the electric current includes a first frequency component and a second frequency component, the circuit arrangement comprising;

a shunt circuit connected across the power source, the shunt circuit being arranged to receive and filter the first frequency component;

a transistor circuit comprising at least one transistor, the transistor circuit being connected in series between the power source and the load, the transistor circuit being arranged to receive and regulate the second frequency component and to provide a regulated current to the load; and

one or more control circuits arranged to provide a respective control signal to each of the at least one transistor so as to control regulation of the second frequency component;

wherein each of the one or more control circuits is further arranged to detect one or more operation parameters associated with a respective one of the at least one transistor, and to determine the respective control signal based on the one or more detected operation parameters.