METHOD OF OPERATING CONTROLLER FOR A POWER CONVERTER, AND A CORRESPONDING CONTROLLER

• US 20140246908A1
• Filed: 03/04/2014
• Published: 09/04/2014
• Est. Priority Date: 03/04/2013
• Status: Active Grant

• Current Assignee: Nanyang Technology University
• Original Assignee: Nanyang Technology University
• Inventors: CHEW, Kin Wai Roy, SIEK, Liter
• Granted Patent: US 9,748,838 B2
• Time in Patent Office: Days
• US Class Current: 307/24
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02M 3/04 by static converters
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence
• CPC Class Codes: H04Q 9/00 Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom

Abstract

A method of operating a controller (200) for a power converter having a plurality of switches couplable to respective electrical devices (106, 108, 110) is disclosed, in which the controller includes a switch activating unit (210), a frequency varying unit (202), a comparator (206) and a selector (208). The method comprises comparing respective electrical parameters of the electrical devices with respective reference electrical parameters by the comparator to obtain associated results; and based on the results, selecting by the selector either no switches or at least one switch to be activated to enable at least two electrical devices to be electrically connected. The activation is performed on receipt of a signal pulse, and if no switches are selected, the signal pulse is skipped by the switch activating unit to reduce power consumption of the controller, and based on the results, a frequency of the signal pulse is varied by the frequency varying unit to further reduce power consumption of the controller. A controller (200) is also disclosed.

Claims

1. A controller for a power converter having a plurality of switches couplable to respective electrical devices, the controller comprising:

a switch activating unit for activating the switches;

a frequency varying unit;

a comparator configured to compare respective electrical parameters of the electrical devices with respective reference electrical parameters to obtain associated results; and

a selector configured to select based on the results, either no switches or at least one switch to be activated to enable at least two electrical devices to be electrically connected,

wherein the activation is performed on receipt of a signal pulse, and if no switches are selected, the signal pulse is skipped by the switch activating unit to reduce power consumption of the controller, and

wherein based on the results, a frequency of the signal pulse is varied by the frequency varying unit to further reduce power consumption of the controller.

2. The controller of claim 1, wherein the plurality of electrical devices include energy storage devices, energy harvesting devices and voltage regulatable devices, and wherein the switches include at least first to fourth sets of switches to selectably connect an energy harvesting device and a voltage regulatable device, or an energy storage device and a voltage regulatable device, or an energy storage device and an energy harvesting device.

3. The controller of claim 2, wherein the energy storage devices include batteries and/or ultra-capacitors.

4. The controller of claim 2, wherein the energy harvesting devices include photovoltaic cells and/or piezoelectric micro-power generators.

5. The controller of claim 2, wherein the first set of switches is configured to be coupled to the energy harvesting devices, the second set of switches is configured to be coupled to the energy storage devices, the third set of switches is configured to be coupled to the voltage regulatable devices, and the fourth set of switches is configured to be coupled to the energy storage devices.

6. The controller of claim 1, wherein the comparator includes a memory device to store digital codes corresponding to at least some of the reference electrical parameters.

7. The controller of claim 6, wherein the comparator further includes a Digital-to-Analog Converter (DAC) to convert the digital codes into the at least some of the reference electrical parameters.

8. The controller of claim 7, wherein the DAC includes a Capacitive DAC (CDAC) and has a resolution of 8-bits.

9. The controller of claim 1, wherein the comparator includes a double-tail latch-type dynamic comparator.

10. The controller of claim 1, wherein the frequency varying unit is configured to periodically generate the signal pulse.

11. The controller of claim 1, wherein the frequency varying unit is configured to receive the signal pulse.

12. The controller of claim 1, wherein the frequency varying unit includes a dual threshold CMOS relaxation oscillator having a dynamic threshold inverter.

13. The controller of claim 12, wherein the dynamic threshold inverter is arranged to use two different threshold voltages to periodically generate the signal pulse.

14. The controller of claim 1, wherein activation of the at least one switch includes sequentially activating the at least one switch to enable transfer of electrical energy between the at least two electrical devices.

15. The controller of claim 1, wherein the comparator and selector are configured to be switched off prior to receipt of the signal pulse.

16. The controller of claim 2, wherein the electrical parameters include voltages.

17. The controller of claim 16, wherein no switches are selected if no energy harvesting device has a voltage higher than a first reference voltage being compared with, and no voltage regulatable device has a voltage lower than a second reference voltage being compared with.

18. The controller of claim 1, wherein the comparator is further configured to compare the electrical parameters of the electrical devices with the reference electrical parameters upon receipt of the signal pulse.

19. The controller of claim 16, wherein varying the frequency includes increasing the frequency if at least one energy harvesting device is consecutively determined to have a voltage higher than a first reference voltage being compared with, or at least one voltage regulatable device is consecutively determined to have a voltage lower than a second reference voltage being compared with.

20. The controller of claim 19, wherein increasing the frequency includes doubling the frequency.

21. The controller of claim 16, wherein varying the frequency includes decreasing the frequency if at least one energy harvesting device is consecutively determined to have a voltage lower than a first reference voltage being compared with, or at least one voltage regulatable device is consecutively determined to have a voltage higher than a second reference voltage being compared with.

22. The controller of claim 21, wherein decreasing the frequency includes halving the frequency.

23. The controller of claim 7, wherein the comparator further includes:

a voltage multiplexer configured to receive the respective electrical parameters of the electrical devices to generate a first signal;

a digital reference multiplexer configured to receive the respective reference electrical parameters to generate a second signal; and

a dynamic comparator configured to receive the first and second signals for performing the comparison.

24. A power converter having a controller and a plurality of switches couplable to respective electrical devices,

wherein the controller includes a switch activating unit for activating the switches;

a frequency varying unit;

a comparator configured to compare respective electrical parameters of the electrical devices with respective reference electrical parameters to obtain associated results; and

a selector configured to select based on the results, either no switches or at least one switch to be activated to enable at least two electrical devices to be electrically connected, and

wherein the activation is performed on receipt of a signal pulse, and if no switches are selected, the signal pulse is skipped by the switch activating unit to reduce power consumption of the controller, and

wherein based on the results, a frequency of the signal pulse is varied by the frequency varying unit to further reduce power consumption of the controller.

25. The power converter of claim 24, wherein the power converter is configured for a wireless sensor operable using energy harvesting.

26. A method of operating a controller for a power converter having a plurality of switches couplable to respective electrical devices, the controller including a switch activating unit, a frequency varying unit, a comparator and a selector, the method comprising:

comparing respective electrical parameters of the electrical devices with respective reference electrical parameters by the comparator to obtain associated results; and

based on the results, selecting by the selector either no switches or at least one switch to be activated to enable at least two electrical devices to be electrically connected,

wherein the activation is performed on receipt of a signal pulse, and if no switches are selected, the signal pulse is skipped by the switch activating unit to reduce power consumption of the controller, and

wherein based on the results, a frequency of the signal pulse is varied by the frequency varying unit to further reduce power consumption of the controller.