Direct current power plant

Patent metadata

Field	Value
Publication number	US-2023392570-A1
Application number	US-202318446922-A
Country	US
Kind code	A1
Filing date	Aug 9, 2023
Priority date	Jun 19, 2015
Publication date	Dec 7, 2023
Grant date	—

Abstract

A DC power plant generating DC power from a variety of engines including a Stirling cycle engine. The DC power plant includes a relatively small start-up power source that is discontinued after the engine is running. A method for producing DC power for a load including starting up an engine using power supplied by a relatively small power supply supplemented by a capacitor bank, providing output from the engine to a generator, producing alternating current (AC) power by the generator, converting the AC power to direct current (DC) power, disabling output of the DC power during a first set of pre-selected conditions, limiting a rate of change of current of the DC power during a second set of pre-selected conditions, reducing conducted and radiated emissions of the DC power, disconnecting the DC power from the load under a third set of pre-selected conditions, and providing the DC power to the load.

First claim

We claim:

1 . Method of producing direct current (DC) power for an electric grid comprising:
driving a permanent magnet synchronous motor generator (PMSMG) whereby the PMSMG generator outputs alternating current (AC) power; converting the AC power to DC power; wherein the PMSMG and the motor drive power board control said driving; and providing the DC power to an electric grid.

2 . Method of claim 1 wherein said driving is performed by a Stirling engine.

3 . Method of claim 1 further comprising, prior to said converting, coupling a motor drive power board and the PMSMG generator, wherein said converting is performed by the motor drive power board.

4 . Method of claim 1 further comprising, prior to said providing:
coupling a DC output breaker and an arc fault detector configured to detect an arc fault condition; and
shunt tripping the DC output breaker.

5 . Method of claim 1 wherein said providing depends on a condition.

6 . Method of claim 5 wherein a rate of change of current of the DC power depends on a second condition.

7 . Method of claim 1 further comprising reducing conducted and radiated emissions of the DC power.

8 . Method of claim 1 wherein disconnecting the DC power from a load depends on a third condition.

9 . Method of claim 1 further comprising shunting heat of said driving into a shunt load.

10 . Method of claim 9 further comprising heating water with the heat.

11 . Method of claim 5 wherein the condition is selected from an overcurrent, a ground fault and combinations thereof.

12 . Method of claim 6 wherein the second condition is an abnormal condition.

13 . The method of claim 8 wherein the third condition is an abnormal condition.

14 . The method of claim 1 further comprising providing the DC power to: an igniter power board; a pump/fan/blower drive; an engine control I/O PCB; a system control PCB; a power control PCB; and combinations thereof.

15 . The method of claim 1 further comprising:
receiving an angle having a waveform;
applying an increment to the angle;
generating a sine/cosine pair for the angle;
generating an inverter waveform based on the sine/cosine pair; and
computing a phase error signal based on the sine and a cosine of the grid voltage;
multiplying the sine by the voltage of the grid supply and defining a signal that contains AC and DC components wherein:
the AC component has an amplitude variation based on amplitudes of the grid supply and the inverter waveform, and having a frequency equal to twice the frequency of the grid supply when loop is locked;
the DC component has an amplitude variation based on a phase error between the grid supply and the inverter waveform;

filtering the phase error thereby eliminating a part of the AC component not relevant to control and defining filtered phase error; and
supplying the filtered phase error to the PI controller.

16 . Method of claim 15 wherein:
the angle has a 16-bit value;
the angle sweeps from 0-360° every 100 μsecs;
the increment has a 32-bit center frequency input and/or a 16-bit delta frequency input driven by a PI controller;
the center frequency input is a fractional value of the angle; and
the delta frequency oscillates about zero.

17 . Method of claim 1 further comprising reporting to a system controller the voltage and the frequency of the electric grid.

18 . Method of claim 1 wherein said providing comprises:
measuring a voltage and a frequency by a first digital phase locked loop;
measuring a phase error by a second digital phase locked loop;
referencing the voltage to the second digital phase locked loop; and
defining a phase lock when:
the phase error is less than a value; and/or
the voltage is within a range.

19 . Method of claim 18 wherein the first digital phase locked loop the voltage and/or the frequency are within a second range.

Assignees

• Deka Products Lp

Inventors

• Schnellinger Andrew A
• Lowell James R
• Finseth Bryan A
• Barber Christopher L
• Sachs Jason M
• Lucas Donald J
• Prescott Shannon
• Kite Jeffrey W
• Fekete Andras K
• Adams Douglas R

Classifications

• F02N11/0859 Primary

  specially adapted to the type of the starter motor or integrated into it · CPC title

• F02G1/043 Primary

  the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines · CPC title

• F02N11/0866

  comprising several power sources, e.g. battery and capacitor or two batteries · CPC title

• F24D11/00

  Central heating systems using heat accumulated in storage masses (self-contained storage heating units F24D15/02) · CPC title

• H02J1/10

  Parallel operation of DC sources · CPC title