Virtual oscillator control of power electronics inverters

Patent metadata

Field	Value
Publication number	US-9484745-B2
Application number	US-201414450972-A
Country	US
Kind code	B2
Filing date	Aug 4, 2014
Priority date	Sep 9, 2013
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

A system includes power electronics inverters connected in a network. The power electronics inverters can utilize measurements at local terminals, without a need to exchange information between other power electronics inverters.

First claim

The invention claimed is:

1. A system, comprising:
an oscillator controller, the oscillator controller including a resistor, a capacitor, an inductor, and a piecewise linear voltage-dependent current source connected in parallel; and
power electronics inverters connected with the oscillator controller in a network, the oscillator controller to generate an oscillating signal to modulate the power electronics inverters;
wherein the power electronics inverters utilize measurements at local terminals, without a need to exchange information between other power electronics inverters for synchronization.

2. The system of claim 1 , wherein the power electronics inverters oscillate as a synchronized alternating current system.

3. The system of claim 1 , wherein voltage limits are respected across a no-load to a maximum rated load range.

4. The system of claim 1 , wherein a distortion of a sinusoidal output of the power electronics inverters is reduced.

5. The system of claim 1 , wherein the power electronics inverters automatically synchronize ac outputs across the network.

6. The system of claim 5 , wherein the synchronization occurs automatically upon adding or removing a power electronics inverter to the network.

7. The system of claim 5 , wherein the synchronization occurs without a phase lock loop to generate sinusoidal reference waveforms or explicit communication between power electronics inverters.

8. The system of claim 5 , wherein the synchronization occurs without a proportional-integral or proportional-integral-derivate controller.

9. The system of claim 5 , wherein the synchronization is agnostic to a number of power electronics inverters and loads.

10. The system of claim 1 , wherein the power electronics inverters further include the oscillator controller implemented as code stored in memory and executed by a processor or as an analog integrated circuit.

11. The system of claim 1 , wherein the power electronics inverters share a load proportional to their size.

12. The system of claim 1 , wherein real and reactive power need not be calculated in real time.

13. The system of claim 1 , wherein the power electronics inverters further include a pre-synchronization circuit to synchronize the other power electronics inverters before adding them to an energized network.

14. A system, comprising:
a power electronics inverter including switching semiconductor devices and passive filtering components;
at least one of a microcontroller to control the switching semiconductor devices, the microcontroller configured to digitize the current and voltage at an output of the power electronics inverter and determine an oscillator voltage based on the current, the switching semiconductor devices being manipulated based on the oscillator voltage, or an analog circuit configured to control the switching semiconductor devices, the analog circuit configured to process a scaled current and voltage at the output of the power electronics inverter and determine an oscillator voltage based on the current, the switching semiconductor devices configured to be manipulated based on the analog oscillator voltage; and
an oscillator controller of the microcontroller, the oscillator controller including a resistor, a capacitor, an inductor, and a piecewise linear voltage-dependent current source connected in parallel, wherein the oscillator controller is configured to determine the oscillator voltage.

15. The system of claim 14 , wherein the switching semiconductor devices are interleaved to reduce operating ripple.

16. The system of claim 14 , wherein the oscillator controller comprises an analog oscillator to determine the oscillator voltage.

17. The system of claim 14 , wherein the microprocessor or analog circuit further includes a pulse width modulator to send a signal to the power electronics switching semiconductor devices to control the switching based on the oscillator voltage.

18. A method, comprising:
an oscillator controller including a resistor, a capacitor, an inductor, and a piecewise linear voltage-dependent current source connected in parallel, an analog to digital converter and accompanying analog circuitry for determining an output current of a power electronics inverter, for:
determining an instantaneous oscillation voltage based on the current; and
controlling switching of the power electronics circuit based on the instantaneous oscillation voltage.

19. The method of claim 18 , wherein the analog circuitry comprises an integrated circuit for determining the output current of the power electronics inverter.

20. The method of claim 18 , further comprising inputting a scaled current into the oscillator controller to determine the oscillation voltage.

Assignees

• Univ Illinois
• Univ Rutgers

Inventors

• Johnson Brian
• Dholpe Sairaj
• Hamadeh Abdullah
• Krein Philip

Classifications

• H02J3/38 Primary

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title

• H02M7/493

  the static converters being arranged for operation in parallel · CPC title

• H02M7/525

  with automatic control of output waveform or frequency (H02M7/517 - H02M7/523 take precedence) · CPC title

• H02M2001/0012

  Electricity · mapped topic

• H02M1/0043

  Converters switched with a phase shift, i.e. interleaved (non-isolated DC/DC converters H02M3/1586) · CPC title