Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
  • H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
  • H02P9/14—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field
  • H02P9/26—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices
  • H02P9/30—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices
  • H02P9/305—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices controlling voltage
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
  • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
  • G05F1/10—Regulating voltage or current
  • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
  • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
  • G05F1/575—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices characterised by the feedback circuit

Definitions

• the present invention relates to a control loop of a digital control device of a rotating electric machine with motor vehicle excitation.
• the invention also relates to a digital controller device comprising this control loop, and a corresponding rotating electric machine.
• a rotating electrical excitation machine is, unlike an electric machine with permanent magnets, capable of producing a motor torque, or of supplying electrical energy, only when its inductor is traversed by a excitation current.
• a common type of rotating electrical excitation machine widely used in the automotive field for alternator and starter functions, includes a rotating inductor and a multi-winding stator.
• the current generated in the stator windings by the rotating inductor is rectified so as to deliver a DC voltage to the battery of the vehicle.
• This voltage depends on the rotational speed of the inductor, the connected load and the excitation current.
• the output voltage must be regulated to remain constant regardless of the rotation speed of the alternator and regardless of the battery charge.
• the output voltage is measured and continuously compared to a setpoint value by a regulator device which controls the excitation current so as to cancel any difference.
• the slaving of the output voltage to a setpoint is based on the theorization of a proportional (P) or integral proportional (PI) control loop.
• phase margin and the gain margin of the system including the regulator, the alternator, a battery and loads.
• phase margin of the open loop transfer (FTBO) function of a slave system must be greater than 45 degrees, and the gain margin must be greater than 13 dB, to consider the system as stable .
• phase margin > 45 °
• gain margin > 13 dB
• the voltage drop of the voltage regulation as a function of the current flow is then increased, and can reach 600 mV, which is considered as a degradation of the performance of the regulation of voltage with respect to a voltage drop of about 200 mV for a 100 A alternator, for example.
• a known solution for limiting the regulation voltage drop when the regulator gain is decreased is the use of an integral part in the control loop.
• the voltage drop can thus be reduced to a value close to 0 mV; however, it is known that the phase margin and the gain margin are slightly affected.
• the object of the present invention is to satisfy this need and is precisely concerned with a control loop of a digital rotary machine control device with motor vehicle excitation.
• This machine is of the type capable of operating as a generator delivering an output voltage adjusted by an excitation current.
• measuring means by sampling the output voltage generating a measurement signal
• error calculating means generating an error signal equal to a difference between the measurement signal and a setpoint value; means for processing this error signal generating a regulation signal comprising an amplifier;
• means for generating a control signal controlling the control means as a function of the regulation signal at the output, means for generating a control signal controlling the control means as a function of the regulation signal.
• the regulation loop according to the invention comprises processing means which furthermore comprise a phase advance filter.
• a Z-transfer function of this phase advance filter is preferably of the form:
• a is a first predetermined coefficient and b is a second predetermined coefficient such that a> b
• a digital output Y n + i of the phase advance filter is related to a digital input X n of this phase advance filter by a recurrence equation of the form:
• Y n + 1 ⁇ ⁇ ⁇ - : Y 1 / b + X, X n Z -1 + X n Z -1 1 / a
• a and b are respectively the first and second predetermined coefficients above.
• the phase advance filter in question then comprises means for implementing this recurrence equation.
• these implementation means comprise, at the input of the phase-advance filter, a multiplier by a predetermined factor and at the output of a divider by this predetermined factor.
• the implementation means further comprise an adder and multiplying elements by inverse values of the first and second predetermined coefficients.
• the phase advance filter is in series with the amplifier.
• the processing means of this control loop further comprise an integrator in parallel with this amplifier and the phase advance filter.
• These processing means furthermore advantageously comprise a saturation block generating a disconnection signal controlling a switch disconnecting the integrator from the error calculation means in the event of detection of a saturation state of the regulation signal.
• the integrator is a low pass filter.
• the phase advance filter has a nominal cutoff frequency which is substantially equal to 22 Hz, an open loop transfer function of the digital controller device having a gain margin substantially equal to 22 dB and a phase margin substantially equal to 80 degrees.
• the invention also relates to a digital regulator device for a rotating electrical machine with motor vehicle excitation, of the type capable of operating as a generator, remarkable in that it comprises a regulation loop having the characteristics described above.
• a motor vehicle-type rotating electrical machine of the type capable of operating as a generator comprising this digital regulator device is likewise covered by the invention.
• FIG. 1 is a diagrammatic representation of a rotating electrical machine with excitation known from the state of the art, provided with a digital regulator device comprising a regulation loop, and its use on the onboard network of a vehicle automobile.
• FIG 2 is a block diagram of a control loop of the digital controller device shown in Figure 1, a type "proportional integral" known from the state of the art.
• Figure 3 is an analog representation of a type of phase advance filter implemented in the control loop according to the invention.
• Figures 4a and 4b show a frequency response of a digital embodiment of the phase advance filter shown in Figure 3 (gain and phase, respectively).
• Figure 5 is a block diagram of a form of digital implementation of a phase advance filter implemented in a preferred embodiment of the control loop according to the invention.
• Figure 6 is a block diagram of a preferred embodiment of the control loop according to the invention.
• the rotary electrical excitation machine shown diagrammatically in FIG. 1 is, by way of non-limiting example, a three-phase alternator 1 provided with a digital regulator device 2.
• the stator 3 of the alternator 1 comprises three windings subjected to the rotating field created by the inductor 4 traversed by an excitation current I e .
• the alternating current produced in the stator 3 is rectified by a rectifying block 5 and filtered by a capacitor 6 so that the alternator 1 delivers a continuous output voltage U b + to the battery 7 and to the on-board vehicle network 8 supplying loads 9 (a connection by a power cable being shown schematically by a self-L and a resistor R).
• the output voltage U b + of the alternator 1 is kept constant when the load 9 and the speed of rotation ⁇ vary by means of a regulation loop 1 0 acting on control means 1 1 of the excitation current. from measurements 1 2 by sampling this output voltage U b +.
• the control means 1 1 of the excitation current I e generally consist of power transistors 1 1 operating in switching and controlled by a rectangular signal PWM variable duty cycle.
• the regulation loop 1 0 is most often an integral proportional control loop equipped with a calculated feedback anti-saturation system of the type shown in FIG. .
• the regulation loop 1 0 comprises, at input, measuring means generally constituted by an analog-digital converter for sampling the output voltage U b + of the alternator 1 and generating a measurement signal U m which is compared with a value of U 0 setpoint.
• Error calculation means 13 generate with a first operator "Diff_1" an error signal e equal to a difference between the measurement signal U m and the setpoint value U 0 .
• the error signal e is amplified, on the one hand, by a first amplifier 14 having a predetermined proportional gain K p , and on the other hand, integrated by an integrator 15.
• An output voltage S a of the first amplifier 14 and an output voltage S of the integrator 15 are summed 16 to produce an intermediate control signal Y.
• a saturation block 17 makes it possible to adapt the data format of the regulation loop 10 to that of means for generating the output PWM control signal, by supplying a regulation signal Y sat from the intermediate control signal Y.
• This control loop 10 of a known type further comprises a calculated feedback anti-saturation system 18, the operation of which is as follows:
• a quantity Y dif f represents a difference between an error generation before saturation Y and saturation Y sat performed by a second operator "Diff_2" 19.
• the anti-saturation system 18 is considered disconnected.
• e is an intermediate error signal at the input of the second amplifier 20 preceding the integrator 15.
• the magnitude Y dif f is non-zero in saturated mode.
• variable Y diff in saturated mode attenuates more or less significantly (according to a saturating gain K Nm of an additional amplifier 21) the loop error s, generated by the integral part 15, 20 via a difference realized by a third operator «Diff_3
• the inventive entity has studied the possibility of adding a phase advance filtering in the regulation loop 10 controlling the alternator 1, if it comprises in particular an integral part 15, 20, 23, as will be explained in connection with Figure 6.
• This attenuation value may be adjusted if lower or higher attenuation is desired depending on the system control by selecting appropriate values of R1 and R2.
• phase advance filter is divided into two basic filters:
• the first predetermined coefficient a is greater than the second predetermined coefficient b.
• the frequency response of the digital phase advance filter 24 is in fact almost similar to that of the analog phase advance filter (same characteristics, a "derivative” part and an “integral” part).
• a form of digital implementation 24 shown in Figure 5 can be given by analyzing a recursion equation derived from the z-transfer function of the form:
• Y n Y n Z "1 - Y n Z " 1 1 / b + X n - X n Z "1 + X n Z " 1 1 / a
• a multiplier 25 by a predetermined factor M at the input makes it possible to increase the accuracy of the calculation of the phase-advance filter 24; the result at the output of the filter 24 is then divided by this predetermined factor M by a divider 26.
• phase advance filter 24 is also implemented by means of an adder 27 and multiplication elements 28, 29 by inverse values of the first and second predetermined coefficients a, b.
• the digital phase advance filter 24 is added in series with the amplifier 14 of the regulation loop 10.
• input signal 1 2 representing the voltage of the battery 7 or the voltage of the "B +" terminal of the alternator 1;
• - Analogue filtering 30 (anti-aliasing filter, anti-voltage ripple), associated with the analog-digital converter 31 and voltage divider 30 in order to adapt the voltage level for the analog-digital converter 31;
• anti-aliasing filter 33 associated with the decimation induced by the generation of the PWM control signal
• saturation block 1 7 making it possible to adapt the data format of the regulation loop 1 0 to that of generating means 35 of the PWM control signal between a minimum value Y m in and a maximum value Y ma x;
• second amplifier 20 (with an integrating gain K, adjusted to guarantee the stability of the regulator device 2 connected to the alternator 1 connected to the battery 7);
• PWM control signal controlling the power electronics 1 1 controlling the excitation current the alternator 1;
• phase advance filter 24 (adjusted to guarantee the stability of the regulator assembly connected to the alternator 1 and connected to the battery 7).
• This phase advance filter 24 has the essential characteristic of having a significant positive phase on a given frequency band. Its nominal cut-off frequency f c is adjusted to obtain maximum phase advance in the control loop 10 in order to obtain on the FTBO of the control system a phase margin and a maximum gain margin.
• the regulation loop 10 is an integral proportional control loop 14, 23 which furthermore comprises, unlike the control loops known from the technical state (such as that shown on FIG. Figure 2), a conditional detection anti-saturation system 36, for optimizing the return time to the unsaturated mode.
• the integral part 23 of the regulation loop 10 comprising the second amplifier 20 and the integrator 34 is connected or disconnected by the saturation block 17 as a function of the saturation state of the regulation signal Y sat .
• the saturation block 17 generates a disconnection signal Cmd controlling the switch 36 applying on the input of the second amplifier 20, either the error signal e, or a zero voltage by a grounding 37.
• the implementation of the saturation detection in the saturation block 17 is performed by a digital algorithm that uses the following signals:
• Cmd Disconnect control signal.
• the saturation detection algorithm is:
• the switch 36 connects the error signal e to the input of the integral part 23 (i.e. with the second integrating gain amplifier K, in series with the low pass filter 34 which performs the function of integration 15).
• the anti-saturation system is considered disconnected.
• e is the intermediate error signal at the input of the second amplifier 20 preceding the low pass filter 34.
• the saturated mode is detected.
• the switch 36 then connects the input of the integral part 23 to a zero voltage in order to stop the evolution of the output voltage s, of the integral part 23.
• the output voltage s, of the integral part 23 remains fixed at a constant value during the saturated mode.
• s is equal to the value of s at the time of switching to saturated mode.
• the inventive entity has found that the implementation in an alternator 1 300A flow of a digital controller device 2 comprising a control loop 1 0 as described above with a phase advance filter 24 having a frequency a nominal cut-off f c substantially equal to 22 Hz allowed to obtain a maximum gain margin substantially equal to 22 dB and a maximum phase margin substantially equal to 80 degrees.
• control loop 1 0 is also an example corresponding to a preferred embodiment of the invention; other locations in the regulation loop 1 0 are alternately feasible and would provide similar advantages in terms of phase margins and gain for high power machines 1.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Control Of Eletrric Generators (AREA)

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• 2014
  • 2014-06-11 FR FR1455284A patent/FR3022416B1/fr not_active Expired - Fee Related
• 2015
  • 2015-06-01 US US15/317,454 patent/US9960718B2/en not_active Expired - Fee Related
  • 2015-06-01 EP EP15729548.6A patent/EP3155718A2/de not_active Withdrawn
  • 2015-06-01 WO PCT/FR2015/051431 patent/WO2015189496A2/fr active Application Filing

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