Power supply for ac elevator

• US 6,732,838 B1
• Filed: 05/16/2002
• Issued: 05/11/2004
• Est. Priority Date: 11/17/1999
• Status: Expired due to Term

• Current Assignee: Fujitec Company Limited
• Original Assignee: Fujitec Company Limited
• Inventors: Hasegawa, Kazunori, Murakami, Shinichi, Nagashima, Shigeru, Shiode, Kazuhiro, Yoshino, Yoshitomo, Okada, Takao
• Primary Examiner(s): Salata, Jonathan
• Application Number:
  US10/129,131
• Time in Patent Office: 726 Days
• Field of Search: 187/290, 187/293, 187/296, 307/66, 307/69, 318/375, 318/376, 318/440, 318/441, 318/139, 318/107, 318/108
• US Class Current: 187/290
• CPC Class Codes: B66B 1/30 effective on driving gear , e.g. acting on power electronics, on inverter or rectifier controlled motor
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 9/062 for AC powered loads
• CPC Class Codes: H02M 3/1582 Buck-boost converters H02M3/1584 takes precedence

Abstract

An a.c. elevator of the invention has a commercial power source (1), an inverter (3) operable with the power from the commercial power source (1) for generating a.c. power, and an electric motor to be driven with the a.c. power generated by the inverter (3). A power source device includes a rechargeable battery (E), a power source circuit (10) for charging and discharging the battery (E), and a control circuit (9) for controlling the voltage to be input to the inverter (3) by controlling the operation of the power source circuit (10). The battery (E) is charged with regenerative power from the motor, the power generated by the battery (E) is supplied to the inverter (3).

Claims

1. In an a.c. elevator having a commercial power source, an inverter operable with the power from the commercial power source for generating a.c. power, and an electric motor to be driven with the a.c. power generated by the inverter,

a power source device for the a.c. elevator characterized in that the power source device comprises a rechargeable/dischargeable battery, a charge/discharge circuit for charging and discharging the battery, and a control circuit for controlling the voltage to be input to the inverter according to a predetermined voltage command serving as a target value by controlling the operation of the charge/discharge circuit, the battery being chargeable with regenerative power from the electric motor, the battery being operable to generate power and supply the power to the inverter;

wherein the predetermined voltage command has a value corresponding to a constant voltage higher than full-wave rectified voltage of the commercial power source.

2. The power source device for an a.c. elevator according to claim 1 wherein the battery comprises a plurality of units in combination, each of the units comprising a plurality of cells.

3. The power source device for an a.c. elevator according to claim 2 wherein each of the cells comprises a nickel-hydrogen cell.

4. The power source device for an a.c. elevator according to claim 2 wherein the control circuit comprises discharge preventing means for preventing discharging of the battery, and the discharge preventing means is operated upon a variation in excess of a threshold value occurring in the amount of charge of each unit or each of the cells.

5. The power source device for an a.c. elevator according to claim 2 wherein the control circuit comprises charge preventing means for preventing charging of the battery, and the charge preventing means is operated upon a variation in excess of a threshold value occurring in the amount of charge of each unit or each of the cells.

6. The power source device for an a.c. elevator according to claim 1 wherein the control circuit determines the priority of charging or discharging by the charge/discharge circuit relative to each other.

7. The power source device for an ac. elevator according to claim 1 wherein the charge/discharge circuit has a charge control element for closing a charge circuit and a discharge control element for closing a discharge circuit, and the charge control element and the discharge control element are on/off-controlled by the control circuit.

8. The power source device for an a.c. elevator according to claim 7, wherein the charge/discharge circuit alternately charges and discharges the battery.

9. The power source device for an a.c. elevator according to claim 1 wherein the control circuit alternately turns on the charge control element and the discharge control element to alternately charge and discharge the battery.

10. The power source device for an a.c. elevator according to claim 9 wherein the control circuit alters the on period of the charge control element and the on period of the discharge control element relative to each other to determine the priority of charging by the charge circuit or discharging by the discharge circuit.

11. The power source device for an a.c. elevator according to claim 10 wherein the control circuit determines the priority of charging or discharging according to the charged state of the battery.

12. The power source device for an a.c. elevator according to claim 10 wherein the control circuit determines the priority of charging or discharging according to the operating state of the elevator.

13. The power source device for an a.c. elevator according to claim 1 wherein the control circuit comprises charge amount control means for maintaining the amount of charge of the battery at an appropriate value.

14. The power source device for an a.c. elevator according to claim 13 wherein the appropriate amount of charge of the battery is about 60% of the rated capacity of the battery.

15. The power source device for an a.c. elevator according to claim 13 wherein the appropriate amount of charge of the battery is an amount of electric power capable of supplying about 30% of the rated power of the electric motor.

16. The power source device for an a.c. elevator according to claim 1 wherein the control circuit comprises discharge restricting means for restricting 5 the discharging of the battery and charge restricting means for restricting the charging of the battery.

17. The power source device for an a.c. elevator according to claim 16 wherein the charge restricting means of the control circuit prevents charging of the battery upon the charged state of the battery exceeding about 80% of the rated capacity thereof to thereby prevent overcharging.

18. The power source device for an a.c. elevator according to claim 16 wherein the discharge restricting means of the control circuit prevents discharging of the battery upon the charged state of the battery dropping below about 30% of the rated capacity thereof to thereby prevent over discharging.

19. The power source device for an a.c. elevator according to claim 16 wherein the discharge restricting means of the control circuit prevents the discharging of the battery while the elevator is held out of operation.

20. The power source device for an a.c. elevator according to claim 16 wherein the charge restricting means and the discharge restricting means of the control circuit comprises a limiter circuit for imposing limitation on the deviation of the input voltage of the inverter from the voltage command thereof.

21. The power source device for an a.c. elevator according to claim 20 wherein the charge-side limiter value of the limiter circuit is set to zero upon the charged state of the battery exceeding about 80% of the rated capacity thereof.

22. The power source device for an a.c. elevator according to claim 20 wherein the discharge-side limiter value of the limiter circuit is set to zero upon the charged state of the battery dropping below about 30% of the rated capacity thereof.

23. The power source device for an a.c. elevator according to claim 20 wherein the discharge-side limiter value of the limiter circuit is set to zero while the elevator is held out of operation.

24. The power source device for an a.c. elevator according to claim 1 wherein the control circuit comprises a discharge preventing means for preventing discharging of the battery under a predetermined condition.

25. The power source device for an a.c. elevator according to claim 1 wherein the control circuit comprises a charge preventing means for preventing charging of the battery under a predetermined condition.

26. The power source device for an a.c. elevator according to claim 24 wherein a given time interval is set as the predetermined condition.

27. The power source device for an a.c. elevator according to claim 24 wherein a predetermined period is set as the predetermined condition.

28. The power source device for an a.c. elevator according to claim 24 wherein a specified day of the week or a specified time zone is set as the predetermined condition.

29. The power source device for an a.c. elevator according to claim 24 wherein the state of the elevator as held out of operation is set as the predetermined condition.

30. The power source device for an a.c. elevator according to claim 24 wherein the control circuit comprises means for presetting capacity measuring means for measuring the capacity of the battery, upon completion of charging of the battery.

31. The power source device for an a.c. elevator according to claim 25 wherein the control circuit comprises means for resetting capacity measuring means for measuring the capacity of the battery, upon completion of discharging of the battery.

32. The power source device for an a.c. elevator according to claim 1 wherein the control circuit comprises means for changing over discharging from the battery to constant-current control while changing overcharging of the battery to constant-current control, and means for detecting the internal resistance of the battery based on the terminal voltage of the battery during discharging and the terminal voltage of the battery during charging to judge the life of the battery from the variation of the internal resistance.

33. The power source device for an a.c. elevator according to claim 1 which comprises an output contact provided between an input terminal of the inverter and the control circuit and controllable for opening and closing, a comparator for comparing the input voltage of the inverter with the terminal voltage of the battery, and control means for closing the output contact upon said input voltage exceeding said terminal voltage.