Claims
- 1. A method of regulating the current in a direct current machine with which are associated
an arrangement for generating a current target value signal, as well as a PWM generator (FIG. 11: 182) whose output signal (PWM2) is controllable by means of a control signal (u_156) and controls the current in the direct current machine, comprising the following steps: a) the pulse duty factor of the PWM generator is controlled using the control signal (u_156); b) using the output signal (PWM2) of the PWM generator, the current in the direct current machine is controlled in such a way that in operation, a pulsed direct current (i_2; i_2′) is obtained in a supply lead thereof; c) a pulsed current-dependent signal (u_2) is derived from this pulsed direct current (i_2; i_2′) and is compared to the current target value signal (PHI1); d) as a function of the result of that comparison, the control signal (u_156) for controlling the PWM generator is modified in such a way that the current in the direct current machine is regulated to the desired target value.
- 2. The method according to claim 1,
wherein the direct current machine is operated in a working range in which its current limiting is constantly active, so that during operation, a pulsed direct current constantly flows in a supply lead of the direct current machine.
- 3. The method according to claim 1 or 2,
wherein the output signal (FIG. 27: RGL_VAL) of a rotation speed controller is used as the current target value signal (PWM_I+).
- 4. The method according to claim 3,
wherein the rotation speed controller is implemented as a digital rotation speed controller.
- 5. The method according to one of the preceding claims,
wherein the arrangement for generating a current target value signal (FIG. 11: 27, 29) outputs a PWM signal (PWM_I−, PWM_I+) in which the information about the desired current target value is contained in the pulse duty factor.
- 6. The method according to claim 5,
wherein the PWM signal outputted as the current target value signal is converted by means of an integrating element (FIG. 6: 311, 312) into an analog target value signal (PHIL) and compared in terms of its amplitude to the pulsed current-dependent signal (u_2) derived from the pulsed direct current (i_2) in order, as a function of the result of that comparison, to influence the control signal (u_156) conveyed to the PWM generator (182) in such a way that the current in the direct current machine (32) is regulated to the desired value.
- 7. The method according to one of the preceding claims,
wherein the pulsed current-dependent signal (u_2) derived from the pulsed direct current (i_2), and the current target value signal (PWM_I+), are generated as pulsed signals, one of these two signals being converted into a smoothed analog signal (PHI1) and the other pulsed signal (u_2) being compared in terms of its amplitude to that smoothed signal.
- 8. The method according to one of the preceding claims,
wherein the direct current machine has specified to it a rotation speed which would require a current lying above the range that can be set by specifying a current target value in that direct current machine.
- 9. The method according to at least one of the preceding claims,
wherein the control signal is generated by a control signal generator which generates, in the motor mode, a control signal which corresponds to a high pulse duty factor, and that control signal is reduced, in accordance with the specified current target value, in such a way that it corresponds to a lower pulse duty factor, corresponding to the specified current target value.
- 10. The method according to claim 9,
wherein an analog signal, which is then converted in an analog/PWM converter into a PWM signal for controlling energy delivery to or energy removal from the direct current machine, is used as the control signal.
- 11. The method according to one of the preceding claims for operating a direct current machine at a MOSFET full bridge circuit which can be operated with alternate switching and at a pulse duty factor modifiable substantially between 0% and 100%, comprising the following steps:
if the driving current of the direct current machine exceeds a specified current target value, the pulse duty factor for the full bridge circuit is reduced by reducing a higher setpoint value; if the braking current of the direct current machine exceeds a specified current target value, the pulse duty factor for the full bridge circuit is raised by raising a low setpoint value.
- 12. The method according to claim 11,
wherein at least one of the setpoint values is rotation-speed-dependent.
- 13. The method according to claim 12,
wherein the setpoint value of the pulse duty factor for generator mode rises with increasing rotation speed, and lies approximately in the range from 0 to 50%.
- 14. A direct current machine for carrying out a method according to one of the preceding claims.
- 15. The direct current machine according to claim 14, comprising an arrangement for monitoring the voltage (UB) at the direct current source (73, 74), which arrangement blocks all the semiconductor switches of the full bridge circuit (78) upon exceedance of a specified upper limit value (U_MAX_OFF) of that voltage (Us).
- 16. The direct current machine according to claim 15, comprising for control purposes a digital control element (23), such as a microprocessor or microcontroller, which has an A/D converter that converts the voltage (UB) at the direct current source into a digital value (U_AD) for further processing in the digital control element (23).
- 17. The direct current machine according to one or more of claims 14 through 16, comprising for control purposes a digital control element (23), such as a microprocessor or microcontroller, which during operation furnishes output signals for controlling the full bridge circuit (78),
each bridge arm having associated with it a commutation module (50, 52, 54) for alternatingly switching on its upper and lower semiconductor switch, which commutation module has at least two signal inputs (e.g. IN1, EN1) that are controllable by means of separate signal outputs of the digital control element (23), and the PWM signal (PWM2) being conveyable to one of those signal inputs (IN1, IN2, IN3), and a signal output, associated with that signal input (IN1, IN2, IN3), of the digital control element (23) being switchable to a high-resistance state in order to enable, from the digital control element, an alternating switching-on of the semiconductor switches of that bridge arm by means of the PWM signal (PWM2).
- 18. The direct current machine according to one or more of claims 14 through 17, comprising for control purposes a digital control element (23), such as a microprocessor or microcontroller, which serves to regulate the rotation speed of the direct current machine and furnishes, at at least one output, a signal (PWM1) for influencing the rotation speed of the direct current machine, and further comprising
an arrangement for limiting that signal to a rotation-speed-dependent value.
- 19. The direct current machine according to claim 18,
wherein that signal (PWM1) is limited, in the context of the braking operation, to a value that decreases with decreasing rotation speed (n) of the direct current machine (32).
- 20. The direct current machine according to claim 18 or 19,
wherein that signal influences, by way of its pulse duty factor (PWM1), the charge state of a first capacitor (159); furthermore a second capacitor (148) is provided which is connected via a resistor arrangement (150, 152) to the first capacitor (159); and the pulse duty factor (PWM2) of the PWM signal conveyed to the full bridge circuit (78) is controlled substantially by the voltage at one of those two capacitors (148, 159).
- 21. The direct current machine according to claim 20,
wherein the second capacitor (148) has a lower capacitance than the first capacitor (159).
- 22. The direct current machine according to claim 20 or 21,
wherein a current limiting arrangement (131) is provided which, upon exceedance of a limit value of the driving current specified by a current target value signal (PWM_I+), modifies the charge of that second capacitor (148) in order to limit the driving current to the current target value signal.
- 23. The direct current machine according to one of claims 20 through 22, wherein a current limiting arrangement (161) is provided which, upon exceedance of a limit value of the braking current (i_2′) specified by a current target value signal (PWM_I−), modifies the charge of that second capacitor (148) in order to limit the braking current to the current target value signal.
- 24. The direct current machine according to claim 22 or 23,
wherein the current limiting arrangement comprises a comparator for a comparison between a current target value signal (PHI1; PHI2) and a pulsed signal (u_2; u_2”) derived from the driving current or braking current.
- 25. The direct current machine according to claim 24,
wherein the comparator has associated with it an integrating element (310, 312; 320, 322) in order to transform a pulsed current target value signal (PWM_I+; PWM_I−) into a smoothed signal (PHI1; PHI2) for comparison to a pulsed current-dependent signal (u_2; u_2″).
- 26. The direct current machine according to one of claims 14 through 25, wherein each upper transistor of a bridge arm has associated with it a storage capacitor (230) which can be charged via the lower transistor of that bridge arm and serves to supply that upper transistor with a control voltage,
comprising a commutation arrangement for commutating those transistors, which commutation arrangement is embodied so as, as a function at least of the position of the rotor (110), in a first bridge arm to switch on only one transistor and in a second bridge arm to switch on the upper and the lower transistor alternatingly, the rotation speed (n) being monitored and, if it falls below a specified rotation speed value, after a specified time has elapsed the upper transistors of the full bridge circuit being briefly blocked and the lower transistors being switched on, in order to charge the storage capacitors (230) of the upper transistors and thereby to ensure reliable control of those upper transistors even at low rotation speeds or if the direct current machine is at a standstill (FIG. 24).
- 27. The direct current machine according to one of claims 14 through 26, wherein the two transistors (80, 81) of a bridge arm each have associated with them an activation circuit (50, 52, 54) which can be enabled and disabled as a function of a first input signal (EN1) and which, in the disabled state, blocks both transistors (80, 81) of the respective bridge arm,
and which, as a function of a second input signal (IN1), in the state enabled by the first input signal (EN1) can be switched over in such a way that either the upper transistor (80) or the lower transistor (81) is made conductive, furthermore having for control purposes a digital control element (23), such as a microprocessor or microcontroller, for generating the first input signal at a first output (EN1) and for generating the second input signal at a second output (IN1), and having a third input signal (80) in the form of a PWM signal having a controllable pulse duty factor (PWM; PWM2), which third input signal can be conveyed from a PWM signal source (182) to the driver circuit (50) in parallel with the second input signal (IN1) and is effective only when the second output (IN1) of the digital control element (23) is switched into a specified switching state.
- 28. The direct current machine according to claim 27,
wherein the specified switching state of the second output (IN1) of the digital control element (23) is a high-resistance state (TRISTATE).
- 29. The direct current machine according to claim 27 or 28,
wherein the third input signal (180) is conveyed to the driver circuit (50, 52, 54) via a diode (260).
- 30. The direct current machine according to one or more of claims 27 through 29,
wherein the amplitude of the third input signal (180) is limited, in particular by means of a Zener diode (186).
- 31. The direct current machine according to one or more of claims 27 through 30,
wherein the driver circuit has an input (223) to which is connected a resistor (252) whose magnitude influences the magnitude of a dead time ((Delta)t) upon switchover between the transistors (80, 81) of the associated bridge arm, and that resistor (252) can be at least partially bypassed by means of a controllable switching element (250) that is controllable by the first input signal (EN1).
- 32. The direct current machine according to claim 31,
wherein the controllable switching element (250) is controlled into a specified switching state when the first output (EN1) of the digital control element (23) assumes a high-resistance state, in order thereby to block the associated bridge arm (80, 81).
- 33. The direct current machine according to one or more of claims 27 through 32,
wherein the pulse duty factor (PWM2) of the PWM signal source (182) is controllable by means of the voltage at a capacitor (148), which voltage, when too high a driving current is flowing in the stator winding arrangement, is modifiable in a specified direction by means of a first current limiting arrangement (131), so that that driving current is lowered by way of a corresponding modification of the pulse duty factor (PWM2), and, when too high a braking current is flowing in the stator winding arrangement, is modifiable in a direction opposite to the specified direction by means of a second current limiting arrangement (161), in order to lower the braking current by way of a corresponding modification of the pulse duty factor (PWM2).
- 34. The direct current machine according to claim 33,
wherein a limiting apparatus for the pulse duty factor (PWM2) is provided in order to prevent the lower transistor (81) of a bridge arm from being constantly open, and the upper transistor (80) constantly closed, in the presence of an extreme value of the pulse duty factor (PWM2).
- 35. The direct current machine according to one or more of claims 27 through 34, which is embodied with at least three phases and has at least three activation circuits (50, 52, 54) for the bridge arms (21, 22, 23);
and having an arrangement (FIG. 31) which, during a commutation, prevents an interruption of the first input signal (EN1) of a driver circuit if that driver circuit must be enabled before and after the commutation.
- 36. An arrangement for controlling or regulating the rotation speed of a direct current machine (32), which arrangement comprises:
a first apparatus (24, 25) which is embodied so as to furnish, at its output (157), a first control signal (PWM1) for controlling the voltage at the direct current machine (32); a second apparatus (24, 27, 29) which is embodied so as to furnish, at its output, a second control signal (PWM_I+; PWM_I−) which serves to influence the level of the current flowing in the direct current machine (32); an arrangement (182) for transforming the first control signal (PWM1) into a signal (PWM2) which controls a pulse duty factor for influencing the energy balance of the direct current machine (32); and a limiting arrangement (131, 161), controlled by the second control signal (PWM_I+; PWM_I−), for the current in the direct current machine (32), which limiting arrangement (131, 161) is embodied so as to respond upon exceedance of the value of that current specified by the second control signal (PWM_I+; PWM_I−), and to modify the first control signal (PWM1) correspondingly.
- 37. The arrangement according to claim 36,
wherein the first apparatus is embodied as a PWM generator (25) controllable by a digital control device (24).
- 38. The arrangement according to claim 36 or 37,
wherein the second apparatus is embodied as a PWM generator (27; 29) controllable by a digital control device (24).
- 39. The arrangement according to claim 37,
wherein an arrangement is provided which converts the output signal of the PWM generator into an analog signal whose value is dependent on the pulse duty factor of the PWM signal.
- 40. The arrangement according to claim 39,
wherein the arrangement for converting the output signal of the PWM generator is embodied as an integrating element (152, 158, 159).
- 41. The arrangement according to claim 40,
wherein the signal at the output of the integrating element (152, 158, 159) is modifiable by means of the limiting arrangement (131, 161) controlled by the second control signal (PWM_I+; PWM_I−) if the current specified by the second control signal is exceeded.
- 42. The arrangement according to claim 40 or 41,
wherein a PWM generator (182) is provided which converts the analog signal (u_156) at the output of the integrating element (152, 158, 159) into a PWM signal for controlling the current in the direct current machine.
- 43. The arrangement according to one of claims 36 through 42,
wherein at least one digital control device (24), such as a microcontroller or microprocessor, is provided for controlling the first apparatus and the second apparatus.
- 44. The arrangement according to claim 43,
wherein the at least one digital control device (24) is embodied so as to regulate the rotation speed of the direct current machine by way of the first control signal (PWM1), and to set the second control signal to a current value that lies in the vicinity of a permissible current of the direct current machine and, in particular, of the maximum permissible current.
- 45. The arrangement according to claim 43 or 44,
wherein the at least one control device is embodied so as to regulate the rotation speed of the direct current machine by way of the second control signal, and to set the first control signal to a value that brings about a continuous response of the limiting arrangement controlled by the second control signal.
- 46. The arrangement according to one of claims 43 through 45,
wherein the at least one control device is embodied so as to regulate the current in the direct current machine to a substantially constant value by the fact that the second control signal is set to a value corresponding to the desired current, and the first control signal (PWM1) is set to a value that brings about a continuous response of the limiting arrangement controlled by the second control signal.
- 47. Use of a direct current motor according to one of claims 14 through 35 to drive a fan.
- 48. The use according to claim 47,
wherein the fan is operated at substantially constant driving current.
- 49. The use according to claim 47 or 48,
wherein the direct current motor has a plurality of phases.
- 50. The use according to claim 49,
wherein a full bridge circuit is provided for supplying current to the phases.
- 51. The use according to one of claims 47 through 50,
wherein the fan is a diagonal or radial fan.
- 52. The use according to clam 51,
wherein a rotation speed controller is provided for the direct current motor (32); and a monitoring arrangement (672) is provided which, during operation of the fan (370) at a specified rotation speed, monitors the motor current and generates an alarm signal (FIG. 38) upon exceedance of a specified current value.
- 53. The use according to claim 52,
wherein the rotation speed controller is embodied in such a way that it generates, as the control output for setting the rotation speed, a current target value for a current controller of the direct current motor (32), and that current target value is monitored in order to generate the alarm signal upon exceedance of a specified value.
- 54. The use according to one of claims 47 through 52,
wherein a rotation speed controller for the direct current motor is provided, also a switching and measuring apparatus which encompasses an automatic shutoff of the direct current motor after attainment of a specified first rotation speed, a time measurement for the elapsed time between shutoff and the attainment of a specified second rotation speed, and an evaluation apparatus for evaluation of that elapsed time.
- 55. The use according to claim 54,
wherein the evaluation apparatus is embodied in order to generate an alarm signal if the elapsed time falls below a specified value.
- 56. The use according to one of claims 47 through 55, wherein
the fan is embodied as a diagonal or radial fan; furthermore, current is supplied to the direct current motor via a current controller that is set to a specified current; furthermore, an apparatus for sensing the rotation speed of the direct current motor is provided; and an alarm apparatus is provided which generates an alarm signal upon exceedance of a specified value of that rotation speed.
Priority Claims (1)
Number |
Date |
Country |
Kind |
100 42 504.6 |
Aug 2000 |
DE |
|
Parent Case Info
[0001] This application is a § 371 of PCT/EP01/09376, filed 14 Aug. 2001.
PCT Information
Filing Document |
Filing Date |
Country |
Kind |
PCT/EP01/09376 |
8/14/2001 |
WO |
|