JP2007236135A - Regenerative controller for switched reluctance motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve control that enables constant braking torque in regenerative braking of an SR motor. <P>SOLUTION: A control unit 1 for executing the drive and regenerative control of the switched reluctance motor is composed so as to set a map for desired braking torque by providing a map storage 9 for storing a map, in which a supply current value to a rotating speed is set for allowing the braking torque to be almost constant during the regenerative braking, a plurality of the maps corresponding to differences in braking torque values, and a setting switch 10 for selecting one arbitrary map. When executing the regenerative braking, it is switched to a regeneration mode if a current detection value reaches a current value read out from the map on the basis of a rotating speed detection value. It is possible to achieve the almost constant braking torque by executing the control of the regenerative braking in the regenerative state or, in some cases, in a state of combining the regenerative state with a reflux state. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a regeneration control device for a switched reluctance motor that performs a regeneration mode in which a switched reluctance motor generates power.

  Conventionally, a salient pole portion made of a plurality of magnetic bodies is provided on a rotor, and a plurality of inward salient pole portions of a stator arranged coaxially so as to surround the rotor are provided, and windings are respectively wound on the inward salient pole portions. In this way, a switched reluctance is formed by forming a magnetizing coil and selectively energizing each magnetizing coil to magnetically attract the salient pole part of the rotor to the inward salient pole part of the stator to generate rotational torque in the rotor. A motor is known. Since this switched reluctance motor does not require a magnet and has a simple structure, it has advantages such as being easy to cope with adverse environments and being able to reduce the size and output at low cost. Application to an apparatus is conceivable, and for example, it is also considered to be used for a drive motor as an electric vehicle such as an electric cart.

When the switched reluctance motor is used for an electric vehicle and the same operation as the accelerator operation in the vehicle using the internal combustion engine is performed, regenerative braking corresponding to the engine brake may be performed during the accelerator off operation. For example, there is a control that switches between a supply mode in which electric power from a battery is supplied to a winding of a stator and a regenerative mode in which an electromotive force generated in the winding during rotor rotation is collected in the battery (see, for example, Patent Document 1). .
Japanese Patent Laid-Open No. 2001-57795

  On the other hand, there is a conventional regenerative braking control in which the supply current from the power source to the winding is constant. Even in that case, when the rotational speed is low and the energization current during regeneration is small, a constant braking torque is obtained regardless of the rotational speed.

  However, in the control for keeping the current supplied to the winding constant, if the rotational speed is high, the braking torque greatly increases in the high rotational speed region. Therefore, a desired braking torque that is constant regardless of the rotational speed is set. Can't get. In an electric vehicle using a switched reluctance motor that performs such control, when an operation corresponding to an engine brake in an accelerator-equipped internal combustion engine-equipped vehicle is performed, in the process of speed reduction (rotation speed reduction) There is a problem that a feeling of braking with a good feeling that the braking torque is constant cannot be obtained.

  Furthermore, if the supply current is increased to meet the desire to obtain a large braking torque in the low rotational speed range in order to improve the running performance, the amount of power generated will be excessive during regenerative braking in the high rotational speed range, resulting in rotation. There is a possibility that not only torque fluctuations with respect to speed changes will become even larger, but also power elements may be damaged.

  In order to solve such a problem and realize a control in which the braking torque can be constant in the regenerative braking of the switched reluctance motor, in the present invention, when the regenerative braking command signal is input, the switched reluctance motor A regenerative control device for a switched reluctance motor having a control circuit for performing a regenerative mode for causing the switched reluctance motor to generate power after a supply mode in which a current is supplied from a power source to the motor, wherein the rotational speed detects the rotational speed of the motor Detection means; current detection means for detecting a current flowing through the motor; and a map showing a relationship between the rotation speed and the current set so that a braking torque is substantially constant within a predetermined range of the rotation speed. And the control circuit has the detected current based on the detected rotation speed in the supply mode. Upon reaching the current value read from came the map was assumed that switching to the regeneration mode controlling the switched reluctance motor.

  In particular, when the rotational speed detected when the regenerative braking command signal is input is within a predetermined low rotational speed range, the control circuit is read from the map based on the rotational speed in the regenerative mode. It is preferable to control the current flowing through the switched reluctance motor so as to obtain a current value. The map may include a plurality of maps corresponding to a plurality of values of the braking torque, and may have switch means for selecting an arbitrary one of the plurality of maps. In addition, the reflux mode may be sequentially performed in the regeneration mode.

  As described above, according to the present invention, the rotation speed is detected when the regeneration mode is performed using the map in which the current is set according to the rotation speed so that the braking torque becomes substantially constant regardless of the change in the rotation speed in the regeneration mode. When the current detection value reaches the current value read from the map based on the value, the mode is switched to the regeneration mode, so that the current value to be switched to the regeneration mode can be changed according to the difference in the rotational speed. By switching to the regenerative mode with a current value smaller than that on the low rotational speed side, it is possible to prevent the current from excessively increasing during regenerative braking. The current value for switching to the regeneration mode can be appropriately set according to the rotational speed by using the map, and it is possible to achieve control to a substantially constant braking torque regardless of the rotational speed.

  In particular, the braking torque constant control in the low rotation speed range can be accurately performed by controlling the current so that the current value read from the map is in the low rotation speed range. In addition, by providing a plurality of maps for each braking torque value and selecting them with a switch, for example, in an electric cart, the braking torque by regenerative braking can be easily adjusted according to the driving skill and preference. Can be greatly improved. In addition, current control that is constant braking torque control can be easily performed by sequentially performing the reflux mode in the supply mode and the regeneration mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram of a drive motor control device mounted on an electric cart to which the present invention is applied. An accelerator operation signal, which may be the amount of depression of an accelerator pedal (not shown), is input to the control unit 1 as a control circuit, and the switch which is the subject of the present invention is corresponding to the drive control signal output from the control unit 1 accordingly. A reluctance motor (hereinafter referred to as an SR motor) 2 is driven and controlled.

  The control unit 1 includes a CPU 3 to which an accelerator operation signal is input, a driver circuit 4 for energizing the SR motor 2, and currents flowing in the phases (U phase, V phase, W phase) of the SR motor 2, respectively. Current detection sensors 5u, 5v, and 5w are provided as current detection means for detection. Further, the SR motor 2 is provided with a rotation sensor 6 as a rotation speed detecting means for detecting the rotation speed of the rotor, and each current detection signal detected by each of the current detection sensors 5u, 5v, 5w, The rotation detection signal detected by the rotation sensor 6 is input.

  The SR motor 2 according to the present invention may have a three-phase structure shown in FIG. For example, the rotor 7 is provided with four radially outward salient pole portions, the annular stator 8 coaxially surrounding the rotor 7 is provided with six radially inward salient pole portions, U-phase, V-phase, and W-phase exciting coils Lu, Lv, and Lw are wound around the salient pole portions of the stator 8 and connected to each other at opposing positions. In the illustrated example, the winding is performed such that one of a pair of opposed salient pole portions of the stator 8 is an N pole and the other is an S pole.

  When the SR motor 2 is rotationally driven, the commutation control of the normal SR motor may be performed, and a detailed description thereof is omitted, but an example of the driver circuit 4 is shown in FIG. In FIG. 2, one excitation coil Lu, Lv, and Lw of each phase is connected through each transistor Q1, Q2, and Q3 connected in parallel to a power supply line (voltage Vb) from a battery (not shown) as a power source. The other exciting coils Lu, Lv, and Lw of each phase are grounded through the transistors Q4, Q5, and Q6. The diodes D1, D2, D3, D4, D5, and D6 are for reflux.

  Each of the transistors Q1 to Q6 responds to a control signal from the CPU 3 so as to switch a coil through which a current flows in accordance with the rotation of the rotor 7 in the order of, for example, the U-phase exciting coil Lu, the V-phase exciting coil Lv, and the W-phase exciting coil Lw. Turn on and off. Further, in this drive control, PWM control is performed, and a PWM control signal is output from the CPU 3 to each of the transistors Q1 to Q6, so that the SR motor 2 can be duty controlled.

  In order to obtain the effect of engine braking in the electric cart in the same manner as the vehicle equipped with the internal combustion engine, for example, the condition for starting the regenerative control is set as a signal input of accelerator-off (accelerator operation amount is 0). Execute. The control procedure for regenerative control is shown below.

  When regenerative control is selected, the control routine shown in FIG. 3 is executed. First, in step ST1, the CPU 3 calculates the rotation speed based on the rotation detection signal detected by the rotation sensor 6 described above. In the next step ST2, the reference supply current value Ia as the current value read from the map is determined based on the rotation speed obtained in step ST1. This reference supply current value Ia is a reference for switching to the regeneration mode.

  In this embodiment, the determination of the reference supply current value Ia is obtained from a map. As shown in FIG. 1, the control unit 1 is provided with a map storage unit 9 that is stored in advance in a memory, for example. For example, a map having a waveform shown in FIG. 4A is set in the map storage unit 9. Further, in the figure, for example, a case where four stages of 1Nm, 2Nm, 3Nm, and 4Nm are divided is shown.

  FIG. 4B is a waveform showing the braking torque with respect to the rotational speed when the current is changed as shown in FIG. As described above, as shown in FIG. 4A, by controlling the supply current flowing to the SR motor 2 based on the change in the supply current, almost the entire rotational speed range DR in which the engine braking effect is desired in the electric cart. In the range, the braking torque due to regeneration can be made substantially constant as shown in FIG. In the low rotation speed range, it is preferable to set the braking torque to be gradually reduced as shown in the drawing in consideration of feeling.

  Further, as shown in FIG. 1, a setting switch 10 is connected to the map storage unit 9, and the setting switch 10 can arbitrarily select four stages of setting torque as in the above-described example. The user can select and set an arbitrary set torque with the setting switch 10 before driving, and can decelerate with the set substantially constant braking torque during regenerative braking. In this way, for example, a relatively small braking torque can be set at the beginner's stage, and a large braking torque can be set as the player becomes advanced. The electric cart applicable to a wide range of users from beginners to advanced users can be provided.

  As described above, when the reference supply current value Ia is determined based on the map shown in FIG. 4A according to the braking torque selected in advance by the user, the supply (supply / reflux) mode is executed in step ST3. In the supply (supply / reflux) mode, a supply mode in which the supply current is continuously supplied may be used. As shown in the examples (FIGS. 5 to 7), the supply current is supplied and the current is supplied via the motor. It may be a supply / reflux mode that performs a reflux state. The supply / reflux mode will be described with reference to FIG. In FIG. 5, the change in inductance according to the rotational displacement between one salient pole part of the rotor 7 and the radially inward salient pole part of the corresponding stator 8, the applied voltage pattern to the excitation coil of the corresponding phase, and The change of the current accompanying it is shown. FIG. 5 is an example in a range (low rotational speed range) DR1 corresponding to a relatively low speed traveling range in FIG.

  As shown in FIG. 5, the inductance changes in a triangular wave shape that increases from the lowest value to the highest value and then decreases to the lowest value according to the rotation of the rotor 7. Further, in this embodiment, an example of a supply / reflux mode in which recirculation is also performed, and an example of the control is PWM control. In addition, what is necessary is just to be able to perform a current supply state and a recirculation | reflux state, and it is not restricted to PWM control. In the case of the illustrated example, the voltage waveform is output as a continuous rectangular pulse wave according to the carrier frequency and according to the duty as shown in the figure. When the voltage waveform is positive in the range where the inductance rises, a supply current is generated, thereby driving the SR motor 2 (drive range in the figure). Further, when a current flows in a range where the inductance decreases, a braking state in which a braking torque is generated is set (braking range in the figure). It should be noted that in a state where no voltage is applied (voltage is 0) in each case, a reflux state is established. In the reflux state in the driving range, the current does not increase, and the current increases in the braking range.

  In step ST4 following step ST3, the current I is detected, and in the next step ST5, it is determined whether or not the detected current value I has reached the reference supply current value Ia determined in step ST2. In the case of FIG. 5, the reference supply current value Ia is I1.

  If it is determined in step ST5 that the detected current value I has reached the reference supply current value Ia (= I1), the process proceeds to step ST6, where the regeneration (reflux / regeneration) mode is executed. The regenerative (reflux / regenerative) mode may be a regenerative mode (FIGS. 6 and 7) in which a regenerative current is continuously flowed, a state in which a regenerative current is passed and a state in which a current is recirculated through a motor. The reflux / regeneration mode (FIG. 5) may be used. When it is determined in step ST5 that the detected current value I has not yet reached the reference supply current value Ia (= I1), the process returns to step ST3.

  In step ST6, the energized transistors (for example, Q1 and Q4 in the case of the U phase) are turned off. As a result, a back electromotive force is generated in the exciting coil (for example, Lu), and generated power is generated, and a regenerative state in which a current flows toward the power source Vb is established. Also at this time, by performing PWM control as shown in the figure, a substantially constant current value I1 corresponding to the duty can be passed.

  In order to perform regenerative braking, a certain current or more must flow through the exciting coil when the inductance decreases. However, the current decreases in the regenerative mode in the low-speed traveling (low rotational speed) region. Therefore, it is necessary to keep the current at a substantially constant value using the reflux mode. Also, when the inductance approaches the minimum value and the regenerative braking is finished soon, there is no need to keep the current constant, and only the regenerative mode is performed without using the return mode. In the case of this regenerative braking, the hatched range in the current waveform shown in FIG. 5 contributes to the braking torque.

  Next, an example in the range DR2 corresponding to the relatively medium speed traveling region shown in FIG. 4 will be described below with reference to FIG. FIG. 6 is a view corresponding to FIG. 5 described above, and a description of the same parts is omitted in the drawing. In this range DR2, since the rotational speed is higher than that in the range DR1, if the supply current value remains I1, the current during regeneration increases. As shown in FIG. 4A, a map is created so that the current value decreases in the range DR2 where the rotational speed is higher than the range DR1. Therefore, a reference supply current value Ia (I2 in FIG. 6) corresponding to the rotational speed is determined from the map shown in FIG. 4A, and the detected current I reaches the reference supply current value Ia (= I2) in step ST5. If it is determined that regeneration has been performed, the regeneration (reflux / regeneration) mode is executed in step ST6.

  In this case, as shown in FIG. 6, the supply current value I2 is lower than the supply current value I1 in the above range DR1, and the regeneration mode is switched at an earlier stage compared to FIG. In the middle rotation speed range DR2, the current flowing through the exciting coil does not decrease with the decrease in inductance even when the regeneration mode is switched, so that it is not necessary to use the reflux mode. Furthermore, FIG. 6 shows that the supply current value I2 is kept low, so that the current value necessary for the desired regenerative braking is maintained and the maximum value is kept low. As a result, as shown in FIG. 4B, the braking torque is substantially constant even in the middle rotational speed range DR2. In addition, the figure is an example, and this range DR2 does not always indicate that the reflux mode is not performed during regeneration.

  Next, an example in the range DR3 corresponding to the relatively high speed traveling region shown in FIG. 4 will be described below with reference to FIG. 7 also corresponds to FIG. 5 in the same manner as described above, and the description of the same parts is omitted in the drawing. Since the rotational speed is higher in this range DR3 than in the range DR2, a smaller reference supply current value Ia (I3 in FIG. 7) is determined as shown in FIG. Since this supply current value I3 becomes the reference supply current value Ia of step ST5, the regeneration mode is switched at an earlier stage than in FIG.

  In this case as well, even if the regeneration mode is switched as in FIG. 6, the current flowing through the exciting coil does not decrease with a decrease in inductance, so that it is not necessary to use the reflux mode. Furthermore, since the supply current value I3 is kept lower, the current value necessary for the desired regenerative braking can be maintained and the maximum value can be kept low. FIG. 7 shows such a case. As shown in FIG. 4B, the braking torque is substantially constant even in the high rotational speed range DR3. In this way, regenerative control that achieves a substantially constant braking torque as shown in FIG. 4B can be realized in the entire rotational speed range DR used, and a braking feeling similar to the engine brake of a vehicle equipped with an internal combustion engine can be obtained. It is done.

  For example, when the accelerator is off and the vehicle is decelerated to a low speed range in a high-speed traveling state, the state indicated by the range DR3 is changed from the state indicated by the range DR3 to the state indicated by the range DR1. In that case, for each control cycle, the supply current value is read from the map based on the detected rotation speed value, and regenerative control based on the supply current value that changes momentarily according to the principle is continuously performed.

  That is, since the supply current value corresponding to the rotational speed is read out from the current waveform in FIG. 4A corresponding to the braking torque selected in advance by the setting switch 10, it is shown in the braking torque waveform in FIG. Thus, in the range DR, a substantially constant braking torque can be obtained regardless of the difference in rotational speed. In addition, by making it possible to select the braking torque in four stages as shown in the figure, the user can easily adjust the braking torque to a desired level, and the convenience of the electric cart is increased. . Note that the number of selections of the braking torque is not limited to the four stages in the illustrated example, may be fixed according to the applied vehicle, and may be a multi-stage setting of a number that can be considered from the use state, Furthermore, a stepless state may be set by a dial operation according to the memory capacity and processing capability.

  The SR motor according to the present invention can make the braking torque due to regenerative braking substantially constant regardless of the rotational speed, and performs a control in which the braking torque due to regenerative braking is made constant not only in the electric vehicle but also in the motor drive device. It can also be applied to mechanical devices having

It is a schematic block diagram of the drive motor control circuit mounted in the electric cart to which this invention was applied. It is a circuit diagram which shows a driver circuit. It is a flowchart which shows the control based on this invention. (A) is a map which shows the change of the supply current with respect to rotational speed, (b) is a figure corresponding to (a) which shows the change of the braking torque with respect to rotational speed. It is a figure which shows the example of the control waveform of the regenerative braking in a low-speed driving | running | working area. It is a figure which shows the example of the control waveform of the regenerative braking in a medium speed driving | running | working area. It is a figure which shows the example of the control waveform of the regenerative braking in a high-speed driving | running | working area.

Explanation of symbols

1 Control unit 2 Switched reluctance motor (SR motor)
3 CPU
4 Driver circuit 5 u, 5 v, 5 w Current detection sensor 6 Rotation sensor 9 Map storage unit 10 Setting switch

Claims (5)

Switch reluctance motor regenerative control device having a control circuit for performing a regenerative mode for generating electric power in the switched reluctance motor after a supply mode in which current is supplied from the power source to the switched reluctance motor when a regenerative braking command signal is input Because
Rotational speed detecting means for detecting the rotational speed of the motor, current detecting means for detecting the current flowing through the motor, and the rotational speed set so that the braking torque is substantially constant within a predetermined range of the rotational speed. And a map showing the relationship between the current and
The control circuit switches to the regeneration mode to control the switched reluctance motor when the detected current in the supply mode reaches a current value read from the map based on the detected rotation speed. A regenerative control device for a switched reluctance motor.   When the rotational speed detected when the regenerative braking command signal is input is within a predetermined low rotational speed range, the control circuit reads the current value read from the map based on the rotational speed in the regenerative mode. The regenerative control device for a switched reluctance motor according to claim 1, wherein a current flowing through the switched reluctance motor is controlled so that A plurality of the maps are provided corresponding to a plurality of values of the braking torque,
The regenerative control device for a switched reluctance motor according to claim 1 or 2, further comprising switch means for selecting any one of the plurality of maps.   The regeneration control device for a switched reluctance motor according to any one of claims 1 to 3, wherein the reflux mode is sequentially performed in the supply mode.   The regeneration control device for a switched reluctance motor according to any one of claims 1 to 4, wherein the recirculation mode is sequentially performed in the regeneration mode.

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