Thermal power generation apparatus and thermal power generation system

Patent metadata

Field	Value
Publication number	US-9966756-B2
Application number	US-201514723509-A
Country	US
Kind code	B2
Filing date	May 28, 2015
Priority date	Jun 17, 2014
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A thermal power generation apparatus includes a control circuit that selects a single operation mode from among a plurality of modes including a normal mode and a specific mode on the basis of a voltage in a commercial system. The normal mode is an operation mode in which alternating-current power output from an inverter is adjusted so that a direct-current voltage in a direct-current power line follows a target voltage. The specific mode is an operation mode in which direct-current power absorbed by an electric power absorber and/or the amount of heat per unit time supplied to a heat engine are/is adjusted so that the direct-current voltage follows the target voltage.

First claim

What is claimed is:

1. A thermal power generation apparatus comprising:
a heat engine that extracts mechanical power from heat supplied by a heat supply source;
a power generator that generates alternating-current power from the extracted mechanical power;
a converter that generates direct-current power from the generated alternating-current power;
an inverter that is connected to the converter via a direct-current power line, the inverter generating alternating-current power from the direct-current power and outputting the alternating-current power to a commercial system;
an electric power absorber that is connected to the direct-current power line connecting the converter and the inverter, the electric power absorber absorbing at least part of the direct-current power transmitted from the converter toward the inverter; and
a control circuit that detects a voltage drop and voltage recovery in the commercial system and selects a single operation mode from among a plurality of modes including a normal mode and a specific mode,
the control circuit, when selecting the normal mode, controlling the inverter to adjust the alternating-current power output from the inverter, thereby causing a direct-current voltage in the direct-current power line to follow a target voltage,
the control circuit, when selecting the specific mode, controlling the inverter to adjust the alternating-current power output from the inverter, thereby causing the direct-current voltage in the direct-current power line to follow the target voltage and controlling the electric power absorber to absorb at least part of the direct-current power,
the amount of the alternating-current power output from the inverter in the specific mode being smaller than that in the normal mode.

2. The thermal power generation apparatus according to claim 1 , wherein:
the control circuit detects a voltage drop and voltage recovery in the commercial system by using an electric parameter detected in the direct-current power line or an electric parameter detected in an alternating-current power line that transmits the alternating-current power output from the inverter; and
the control circuit switches the operation mode from the normal mode to the specific mode upon detection of the voltage drop or switches the operation mode from the specific mode to the normal mode upon detection of the voltage recovery.

3. The thermal power generation apparatus according to claim 2 , wherein:
the electric parameter is a voltage, a direct-current voltage, an electric current, an electric field, or a magnetic field.

4. The thermal power generation apparatus according to claim 1 , wherein:
the control circuit controls the inverter to set the alternating-current power output from the inverter to zero in a case where the voltage recovery is not detected within a limited time after switching from the normal mode to the specific mode.

5. The thermal power generation apparatus according to claim 1 , further comprising a connecting mechanism that connects the inverter and the commercial system,
the control circuit controlling the connecting mechanism to break connection between the inverter and the commercial system in a case where the voltage recovery is not detected within a limited time after switching from the normal mode to the specific mode.

6. The thermal power generation apparatus according to claim 1 , wherein:
the amount of direct-current power absorbed by the electric power absorber in the specific mode is larger than that in the normal mode.

7. The thermal power generation apparatus according to claim 1 , wherein:
the electric power absorber includes a resistor and a semiconductor switch connected to the resistor.

8. The thermal power generation apparatus according to claim 1 , wherein:
the electric power absorber includes a capacitor and a charge-discharge circuit connected to the capacitor, the charge-discharge circuit adjusting an electric current that flows into the capacitor and an electric current that flows out of the capacitor.

9. The thermal power generation apparatus according to claim 8 , wherein:
the electric power absorber further includes a power storage state detector that detects a power storage state of the capacitor.

10. The thermal power generation apparatus according to claim 8 , wherein:
the charge-discharge circuit includes a DC-DC converter.

11. The thermal power generation apparatus according to claim 8 , wherein:
the thermal power generation apparatus uses the direct-current power stored in the capacitor as power for activating the thermal power generation apparatus.

12. The thermal power generation apparatus according to claim 1 , wherein:
the heat engine is a Rankine cycle engine including a pump that feeds a working fluid by pumping, a first heat exchanger that provides heat from the heat supply source to the working fluid, an expander, and a second heat exchanger that discharges heat from the working fluid; and
the pump, the first heat exchanger, the expander, and the second heat exchanger are connected in this order.

13. The thermal power generation apparatus according to claim 1 , wherein:
the control circuit, when selects the specific mode, (i) controls the inverter to adjust the alternating-current power output from the inverter so that the direct-current voltage in the direct-current power line follows the target voltage, (ii) controls the electric power absorber to absorb at least part of the direct-current power, and (iii) controls the heat engine to adjust an amount of heat per unit time supplied to the heat engine.

14. The thermal power generation apparatus according to claim 13 , wherein:
the amount of heat per unit time supplied to the heat engine in the specific mode is smaller than that in the normal mode.

15. The thermal power generation apparatus according to claim 14 , wherein:
the amount of direct-current power absorbed by the electric power absorber in the specific mode is larger than that in the normal mode; and
the amount of heat per unit time supplied to the heat engine in the specific mode is larger than zero and not more than that in the normal mode.

16. The thermal power generation apparatus according to claim 11 , wherein:
the heat engine is a Rankine cycle engine including a pump that feeds a working fluid by pumping, a first heat exchanger that provides heat from the heat supply source to the working fluid, an expander, and a second heat exchanger that discharges heat from the working fluid;
the pump, the first heat exchanger, the expander, and the second heat exchanger are connected in this order; and
the control circuit adjusts an amount of heat per unit time supplied to the expander by the pump.

17. The thermal power generation apparatus according to claim 13 , wherein:
the heat engine is a Rankine cycle engine including a pump that feeds a working fluid by pumping, a first heat exchanger that provides heat from the heat supply source to the working fluid, an expander, and a second heat exchanger that discharges heat from the working fluid;
the pump, the first heat exchanger, the expander, and the second heat exchanger are connected in this order;
the Rankine cycle engine further includes a bypass pathway that bypasses the expander and a bypass valve provided in the bypass pathway; and
the control circuit adjusts an amount of heat per unit time supplied to the expander by the pump and the bypass valve.

18. The thermal power generation apparatus according to claim 1 , wherein:
the heat engine includes an expander.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Konoto Masaaki
• Tomigashi Yoshio
• Nishiyama Noriyoshi
• Hikichi Takumi
• Okaichi Atsuo
• Kido Osao

Classifications

• F01K11/00

  Plants characterised by the engines being structurally combined with boilers or condensers · CPC title

• F01D15/10

  Adaptations for driving, or combinations with, electric generators · CPC title

• H02J7/1415

  with a generator driven by a prime mover other than the motor of a vehicle · CPC title

• F01K13/02

  Controlling, e.g. stopping or starting · CPC title

• H02P9/102

  for limiting effects of transients · CPC title