Method for controlling a power drive system

• US 6,538,412 B1
• Filed: 04/12/2001
• Issued: 03/25/2003
• Est. Priority Date: 07/07/1999
• Status: Expired due to Term

• Current Assignee: DaimlerChrysler Rail Systems GmbH (Bombardier Incorporated)
• Original Assignee: DaimlerChrysler Rail Systems GmbH (Bombardier Incorporated)
• Inventors: Klose, Christian, Unger-Weber, Frank
• Primary Examiner(s): Leykin, Rita
• Application Number:
  US09/786,533
• Time in Patent Office: 712 Days
• Field of Search: 318/800, 318/803, 318/801, 318/268-272, 318/362-369, 363/34
• US Class Current: 318/801
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 9/16 using ac induction motors
• CPC Class Codes: H02M 5/4585 having a rectifier with controlled elements
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

To minimize the energy required for operation of a rail vehicle, in a drive system that has an intermediate circuit converter 1 and a three-phase motor 7 fed by it, the intermediate circuit voltage in the intermediate circuit 12 and/or the magnetic flux in the drive motor 7 are optimized to correspond to the actual operating requirements, including, if necessary, the energy expenditure for the auxiliaries 9 that are provided to cool the components.

Claims

1. A method to control a variable-speed high-power drive system that comprises at least one three-phase motor that is designed for constant input power above a specified speed and is fed from an intermediate circuit converter with a variable intermediate circuit voltage, whereby the intermediate circuit converter is fed from a power line and whereby the intermediate circuit voltage in the speed range below the specified speed is reduced from its maximum value such that the intermediate circuit voltage is not reduced below a minimum voltage specified by the power supply voltage that occurs during operation, the method comprising the steps of:

(a) transitioning the intermediate circuit voltage, in a speed dependent manner, from the reduced intermediate circuit voltage to the maximum intermediate circuit voltage in the speed range above the specified speed to a maximum speed; and

(b) above the specified speed and up to the maximum speed, and thereby in the lower range of the torque to be generated or braked by the drive motor, keeping the intermediate circuit voltage at least approximately at the low level that it has below the specified speed up to the maximum speed.

2. The method as claimed in claim 1, wherein the intermediate circuit voltage at each operating point is set to achieve the minimum overall power loss of the vehicle.

3. The method as claimed in claim 2, wherein a magnetic flux in the drive motor during field weakening is steadily reduced toward higher speeds, and results from the intermediate circuit voltage, whereby the magnetic flux in a pulse mode of the inverter is reduced as a function of the torque to be applied or braked by the drive motor, so that the minimum sum of the power losses in the inverter and drive motor results.

4. The method as claimed in claim 2, wherein the drive system is cooled by means of auxiliary operations such as pumps and ventilators, whereby to achieve a specified temperature of at least one component or a part of said component in the drive system that has a high thermal time constant, the cooling power is modulated to a sharply reduced value that is far below the maximum cooling power, and above the specified temperature is increased to the maximum cooling power as a function of the current temperature of at least one component or a part of said component.

5. The method as claimed in claim 2, wherein the cooling power is controlled proportional to the power loss currently occurring in the drive system in components that have a low thermal time constant.

6. The method as claimed in claim 3, wherein the drive system is cooled by means of auxiliary operations such as pumps and ventilators, whereby to achieve a specified temperature of at least one component or a part of said component in the drive system that has a high thermal time constant, the cooling power is modulated to a sharply reduced value that is far below the maximum cooling power, and above the specified temperature is increased to the maximum cooling power as a function of the current temperature of at least one component or a part of said component.

7. The method as claimed in claim 6, wherein the cooling power is controlled proportional to the power loss currently occurring in the drive system in components that have a low thermal time constant.

8. The method as claimed in claim 3, wherein the cooling power is controlled proportional to the power loss currently occurring in the drive system in components that have a low thermal time constant.

9. The method as claimed in claim 1, wherein a magnetic flux in the drive motor during field weakening is steadily reduced toward higher speeds, and results from the intermediate circuit voltage, whereby the magnetic flux in a pulse mode of the inverter is reduced as a function of the torque to be applied or braked by the drive motor, so that the minimum sum of the power losses in the inverter and drive motor results.

10. The method as claimed in claim 9, wherein the drive system is cooled by means of auxiliary operations such as pumps and ventilators, whereby to achieve a specified temperature of at least one component or a part of said component in the drive system that has a high thermal time constant, the cooling power is modulated to a sharply reduced value that is far below the maximum cooling power, and above the specified temperature is increased to the maximum cooling power as a function of the current temperature of at least one component or a part of said component.

11. The method as claimed in claim 9, wherein the cooling power is controlled proportional to the power loss currently occurring in the drive system in components that have a low thermal time constant.

12. The method as claimed in claim 1, wherein the drive system is cooled by means of auxiliary operations such as pumps and ventilators, whereby to achieve a specified temperature of at least one component or a part of said component in the drive system that has a high thermal time constant, the cooling power is modulated to a sharply reduced value that is far below the maximum cooling power, and above the specified temperature is increased to the maximum cooling power as a function of the current temperature of at least one component or a part of said component.

13. The method as claimed in claim 12, wherein below specified maximum temperature and power loss values in the drive system, the cooling power is increased only if the total additional energy that must be expended for the cooling is less than the sum of the additional electrical energy losses that occur in the drive system in the absence of cooling.

14. The method as claimed in claim 12, wherein individual components of the drive system have their own associated auxiliary operations for cooling, and that the cooling power of these cooling operations is controlled selectively as a function of the temperature and/or load of the corresponding component.

15. The method as claimed in claim 12, wherein the cooling power is controlled proportional to the power loss currently occurring in the drive system in components that have a low thermal time constant.

16. The method as claimed in claim 1, wherein the cooling power is controlled proportional to the power loss currently occurring in the drive system in components that have a low thermal time constant.

17. The method as claimed in claim 16, wherein below specified maximum temperature and power loss values in the drive system, the cooling power is increased only if the total additional energy that must be expended for the cooling is less than the sum of the additional electrical energy losses that occur in the drive system in the absence of cooling.

18. The method as claimed in claim 1, wherein a magnetic flux in the drive motor is de-energized in the absence of a torque requirement, and the power converter and inverter are de-actuated.

19. The method as claimed in claim 18, wherein the auxiliary operations used for cooling are adjusted to the varying load requirements, to the point where they can be de-actuated completely.

20. A control device to control a variable-speed high-power drive system comprising at least one three-phase motor that is designed for constant input power above a specified speed and is fed from an intermediate circuit converter with a variable intermediate circuit voltage, whereby the intermediate circuit converter is fed from a power line and whereby the intermediate circuit voltage in the speed range below the specified speed is reduced from its maximum value such that the intermediate circuit voltage is not reduced below a minimum voltage specified by the power supply voltage (contact line voltage) that occurs during operation, and in the speed range above the specified speed, starting from the reduced intermediate circuit voltage, there is a speed-dependent transition to the maximum intermediate circuit voltage at maximum speed, wherein, in the drive system, the intermediate circuit voltage at speeds of the drive motor in a block mode of the power inverter and thereby in the lower range of the torque to be applied or braked by the drive motor is controlled at least approximately to a value that corresponds to the intermediate circuit voltage in the intermediate circuit below the specified speed of the drive motor, and is set so that at each operating point, the result is a minimum overall power loss for the overall drive system.