JP2009136061A - Control device of switched reluctance motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a switched reluctance motor which can prevent damage caused by the overheating of an SR motor and a switching element, and can maximally acquire a motor output at a rise of a temperature, while gradually lowering the motor output even if temperatures of the switched reluctance motor (SR motor) and the switching element are raised. <P>SOLUTION: The control device 1 of the SR motor 3 comprises: the SR motor 3; temperature sensors 30a, 30b arranged in a drive circuit 4; a current limit determination part 49 which sets a true current limit value on the basis of temperatures detected by the temperature sensors 30a, 30b; a current command value operation part 50 which sets a target output of the SR motor 3; and a current command value determination part 51 which creates a current command value on the basis of the target output when the current limit value set by the current limit determination part 49 is made to coincide with a maximum output of the target output which is set by the current command value operation part 50. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for a switched reluctance motor.

2. Description of the Related Art Conventionally, a switched reluctance motor (hereinafter referred to as an SR motor) in which a rotor has a salient pole structure and a coil is wound around a salient pole provided on a stator side is known. This SR motor control device has a drive circuit for sequentially switching coils to be fed in order to rotate the rotor. This drive circuit has a switching element for selectively supplying a current to one of the coils for each coil. The switching element performs pulse width modulation (PWM) control.
By the way, in order to protect the switching element of the SR motor control device from overheating and prevent damage due to overheating, a temperature sensor is provided in the control device, and current supply is controlled based on the temperature detected by the temperature sensor. Various technologies have been proposed.

  For example, based on a signal indicating a request for the output of the SR motor, a drive current target value for satisfying this request can be obtained, and the switching element can be supplied without causing thermal destruction based on the temperature detected by the temperature sensor. There is a technique for obtaining a drive current allowable value which is a maximum value of a correct drive current. According to this, when the drive current target value is less than the drive current allowable value, the drive current target value is output as the drive current instruction value, and when the drive current target value is greater than or equal to the drive current allowable value, the drive current allowable value is output as the drive current. It can be output as an instruction value. For this reason, damage due to overheating of the switching element can be prevented, and the maximum motor output at that temperature can be obtained (see, for example, Patent Document 1).

Further, in addition to the pulse width modulation control means for controlling the pulse width modulation of the switching element, a rectangular wave control means for controlling the rectangular wave of the switching element is provided, and the temperature detected by the temperature sensor exceeds a predetermined temperature. Some switching elements use rectangular wave control instead of pulse width modulation control. According to this, when the temperature of the control device rises, the switching element is set to rectangular wave control with less heat generation, so that further temperature rise of the control device can be suppressed (see, for example, Patent Document 2). ).
JP 11-346493 A Japanese Patent No. 3580133

  However, until the switching element reaches a predetermined temperature at which there is a risk of damage due to overheating, it is excellent in terms of obtaining the maximum motor output at that temperature and suppressing the temperature rise. The maximum motor output cannot be obtained only by the control, and in order to change from pulse width modulation to rectangular wave control without changing the output, it is necessary to select an element having a large capacity in advance, and there is a problem that costs increase.

  Therefore, the present invention has been made in view of the above-described circumstances, and even if the temperature of the SR motor or the switching element rises, the motor output is gradually reduced, and the SR motor or the switching element is damaged by overheating. An inexpensive control device for a switched reluctance motor capable of preventing the motor output at the time of temperature rise and obtaining the maximum output.

In order to solve the above-mentioned problem, the invention described in claim 1 includes a rotor having a rotor salient pole, a stator having a stator salient pole, and a plurality of coils wound around the stator salient pole. A switched reluctance motor, a drive circuit that switches a current supply line from a power source to the plurality of coils using a plurality of switching elements, and controls the energization state of the plurality of coils, the switched reluctance motor, and Motor limit value setting for setting a motor current limit value that can be supplied to the switched reluctance motor based on a temperature sensor provided in the drive circuit and a temperature detected by a temperature sensor provided in the switched reluctance motor And a temperature detected by a temperature sensor provided in the drive circuit, A drive circuit limit value setting means for setting a drive circuit current limit value that can be supplied to the dynamic circuit, a motor current limit value set by the motor limit value setting means, or the drive circuit limit value setting means Current limit value setting means for setting a lower one of the drive circuit current limit values as a true current limit value, target output setting means for setting a target output of the switched reluctance motor, and the current limit value setting means Current command value generating means for generating a current command value based on the target output when the true current limit value set by the step is made to correspond to the maximum output of the target output set by the target output setting means Rotation position detection means for detecting the rotation position of the rotor, and the rotation position detection means. A rotational speed detecting means for detecting the rotational speed of the rotor based on the rotational position; the current command value generated by the current command value generating means; and the rotational speed detected by the rotational speed detecting means. Accordingly, an energization state setting means for setting an energization angle and an advance angle for energization of the switched reluctance motor, the rotational position detected by the rotational position detection means, and the energization set by the energization state setting means Energization timing output means for outputting an energization timing signal to the switched reluctance motor based on an angle and the advance angle; and current detection means for detecting a current energized to the switched reluctance motor as a current detection value; The current command value generated by the current command value generation means and the current detection means are detected. The pulse width modulation signal generation means for generating a pulse width modulation signal based on the deviation from the detected current value, and the pulse width modulation signal generation based on the energization timing signal output by the energization timing output means Pulse width modulation signal output means for outputting the pulse width modulation signal generated by the means, the motor limit value setting means, the first motor temperature to start lowering the motor current limit value, and the motor current limit value Is set in advance, and the drive circuit limit value setting means sets the first drive circuit temperature at which the drive circuit current limit value starts to be lowered and the drive circuit current limit value to 0 ampere. The second drive circuit temperature is set in advance, and the drive circuit is output by the energization timing output means. The energization timing signal, and in response to said pulse width modulated signal output by the pulse width modulation signal output means and sequentially switching that the turn-on states of the plurality of coils.
In this case, as in the invention described in claim 2, one end portions of the plurality of coils are connected to each other to form a neutral point, and each of the driving circuits has the two switching elements connected in series. A plurality of arms connected in parallel to the power source, and one of the plurality of arms, the neutral point being connected between the two switching elements, and the plurality of arms The other arm of the plurality of coils, the other end of each of the plurality of coils being connected one by one between the two switching elements, and the one arm having the neutral point connected thereto, or the plurality of the plurality of coils. Any one of the other arms to which the other ends of the coils are connected may be connected to the energization timing output means, and the other may be connected to the pulse width modulation signal output means.
By configuring in this way, it is possible to determine the maximum current value that can be supplied to the coil and the drive circuit of the switched reluctance motor at the time of temperature rise, and the lower value of both is set to the true current limit value. By doing so, damage due to overheating of the switched reluctance motor and the switching element can be prevented. For example, by making this maximum current value correspond to the maximum output, the current value for generating the current target output (requested output) can be determined.
Further, the energization timing and the pulse width modulation signal for each current value supplied to the coil can be optimized by the energization state setting means and the pulse width modulation signal generation means.

According to a third aspect of the present invention, the plurality of temperature sensors are provided on the coil wound around the stator salient pole, and are provided in the vicinity of the one arm to which the neutral point is connected. It is characterized by.
With this configuration, it becomes possible to know the temperature of the highest temperature part of the drive circuit and the temperature of the highest temperature part of the switched reluctance motor. . In addition, since the true current limit value can be set based on these temperatures, it is possible to reliably prevent damage caused by overheating of the switched reluctance motor and switching elements, and to ensure maximum motor output when the temperature rises. Obtainable.

According to a fourth aspect of the present invention, there is a temperature difference between a location where the temperature sensor is provided and a location where the maximum temperature of the coil is detected, in the temperature detected by the temperature sensor provided on the coil. And a temperature difference generated between a location where the temperature sensor is provided and the switching element of the one arm in a temperature detected by a temperature sensor provided in the vicinity of the one arm. It is characterized by correcting.
In this way, by setting the temperature sensor to a position that generates a large amount of heat and a position that is easy to assemble, the temperature of the hottest part of the switched reluctance motor can be obtained even when the layout of the temperature sensor is limited. Can be accurately detected, and the temperature of the switching element having the highest temperature in the drive circuit can be accurately detected.

According to the first and second aspects of the invention, the maximum current value that can be supplied to the coil of the switched reluctance motor and the drive circuit when the temperature rises can be determined. By setting the low value as the true current limit value, damage due to overheating of the switched reluctance motor and the switching element can be prevented. For example, by making this maximum current value correspond to the maximum output, the current value for generating the current target output (requested output) can be determined. For this reason, it is possible to prevent damage due to overheating of the switched reluctance motor and the switching element, and it is possible to gradually decrease the motor output even when the temperature of the switched reluctance motor and the switching element rises. Therefore, even if the switched reluctance motor or the switching element reaches a predetermined temperature at which there is a risk of damage due to overheating, it can be prevented that the driving of the SR motor is suddenly stopped without any prior notice.
Furthermore, the energization timing and the pulse width modulation signal for each current value supplied to the coil can be optimized by the energization state setting means and the pulse width modulation signal generation means. For this reason, it becomes possible to obtain the maximum motor output when the temperature rises while suppressing the cost.

  According to the third aspect of the present invention, it is possible to know the temperature of the highest temperature portion of the drive circuit and to know the temperature of the highest temperature portion of the switched reluctance motor. It becomes possible. In addition, since the true current limit value can be set based on these temperatures, it is possible to reliably prevent damage caused by overheating of the switched reluctance motor and switching elements, and to ensure maximum motor output when the temperature rises. Obtainable.

  According to the fourth aspect of the present invention, by setting the temperature sensor to a position where the amount of heat generation is large and a position where it can be easily assembled, even if there is a restriction on the layout of the temperature sensor, It becomes possible to accurately detect the temperature of the highest temperature part, and to accurately detect the temperature of the switching element having the highest temperature in the drive circuit. For this reason, the characteristic of a switched reluctance motor can be improved more.

Next, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the configuration of a control device for a switched reluctance motor (hereinafter referred to as SR motor) is shown. The control device 1 is used for an electric cart, for example, and includes a drive circuit 4 connected to a switched reluctance motor (hereinafter referred to as SR motor) 3 and a driver unit 5 that controls the drive circuit 4. It is configured to include.

The SR motor 3 includes a substantially cylindrical stator 11 and a rotor 12 that is rotatably disposed inside the stator 11. The stator 11 has a substantially annular stator core 13. The stator core 13 is provided with six stator salient poles 14 projecting radially inward, around which three-phase (U-phase, V-phase, W-phase) coils Lu, Lv, Lw are wound. The coils Lu, Lv, Lw of each phase are formed by winding windings around a pair of stator salient poles 14 that are opposed in the radial direction. In the SR motor 3, a temperature sensor 30a is attached to any one of the coils Lu, Lv, Lw of each phase serving as a heat source (on the V-phase coil Lv in the first embodiment). Yes.
The rotor 12 includes an output shaft 15 and a rotor salient pole 16 protruding in the radial direction. The output shaft 15 is provided with a resolver 17 that is a rotation detection device that detects the rotation angle of the rotor 12.

  The coils Lu, Lv, and Lw of each phase are star-connected so that one end portions of the windings have the same potential, and one end portion of the wire and the windings of the coils Lu, Lv, and Lw of each phase are connected. A total of four locations at the other end of each are electrically connected to the drive circuit 4. One current sensor 21 for detecting each phase current (winding current) supplied to the SR motor 3 is provided between the other end of the winding and the drive circuit 4.

The drive circuit 4 is, for example, a PWM inverter using pulse width modulation (PWM), and a smoothing capacitor 32 and four arms 41, 42, 43, and 44 in which switching elements are arranged in parallel to a battery 31 that is a power source. It has the structure connected to.
In the first arm 41, one end of each phase coil Lu, Lv, Lw, that is, a neutral point 46 of star connection is connected between two switching elements NH, NL connected in series. In the second arm 42, the other end of the U-phase coil Lu is connected between two switching elements 2H and 2L connected in series.

In the third arm 43, the other end of the V-phase coil Lv is connected between two switching elements 3H and 3L connected in series. In the fourth arm 44, the other end of the W-phase coil Lw is connected between two switching elements 4H and 4L connected in series. Of these four arms 41, 42, 43, and 44, a temperature sensor 30b is attached in the vicinity of the first arm 41 to which the neutral point 46 is connected.
More specifically, the temperature sensor 30b is provided at a position close to the switching element NH and the switching element NH of the heat sink connected to the switching element NL for cooling the switching element NH and the switching element NL. Is attached.

Needless to say, the mounting position of the temperature sensor 30b is not limited to the above-described position, and the temperature sensor 30b may be disposed at a position close to the switching element NH and the switching element NL. For example, the temperature sensor 30b may be directly attached to the surface of either the switching element NH or the switching element NL. Moreover, you may attach each of the temperature sensor 30b comprised from two sensors directly to each of the surface of switching element NH and switching element NL.
Each temperature sensor 30a, 30b is composed of a temperature sensitive resistor such as a thermistor, for example, and the resistance value changes according to a temperature change. Further, each of the switching elements NH, NL, 2H to 4L includes a transistor such as a field effect transistor (FET) and a diode that prevents reverse flow between the drain and source of the FET (transistor) with respect to the battery 31. And connected in parallel.

  The drains of the transistors NH, 2H, 3H, and 4H arranged on the high potential side are connected to the positive terminal of the battery 31. The sources of the transistors NL, 2L, 3L, L arranged on the low potential side are connected to the negative terminal of the battery 31. The driver unit 5 is connected to the gates of the transistors NH, NL, 2H to 4L.

  The driver unit 5 includes, for example, a motor overheat protection unit 47, a drive circuit overheat protection unit 48, a current limit determination unit 49 as a current limit value setting unit, a current command value calculation unit 50 as a target output setting unit, A current command value determination unit 51 as a current command value generation unit, a position detection unit 52 as a rotation position detection unit, a rotation speed calculation unit 53 as a rotation speed detection unit, a map selection unit 56, and an energization state setting unit A control map storage unit 57, an energization timing output unit 61 as an energization timing output unit, a current detection unit 62 as a current detection unit, a current control unit 63 as a pulse width modulation signal generation unit, and a pulse width modulation A PWM signal output unit 64 as signal output means is provided.

  The motor overheat protection unit 47 detects the coil Lu, Lv, Lw of each phase of the SR motor 3 and the drive circuit 4 based on the winding temperature detected by the temperature sensor 30a attached on the V-phase coil Lv. The current limit value (motor current limit value) that can be supplied to is set. The motor overheat protection unit 47 includes a coil temperature detection unit 47a that detects the winding temperature of the V-phase coil Lv based on a change in the resistance value of the temperature sensor 30a, and a current limit for the winding temperature of the V-phase coil Lv. Coil temperature limit setting unit 47b for setting values, winding temperatures detected by coil temperature detection unit 47a, and current limit values set by coil temperature limit setting unit 47b, coils Lu and Lv for each phase , Lw and a current limit calculation unit 47c for calculating a current limit value that can be supplied to the drive circuit 4.

The winding temperature of the V-phase coil Lv detected by the coil temperature detection unit 47a is the winding temperature of the entire coils Lu, Lv, and Lw.
It is also possible to correct the detection result of the temperature sensor 30a. That is, for example, in this first embodiment, the temperature sensor 30a is mounted on the V-phase coil Lv, and this is set as the temperature of all the coils Lu, Lv, Lw. The place where the line temperature is maximum is inside the wound coils Lu, Lv, Lw. For this reason, since it is difficult to attach the temperature sensor 30a to a location where the winding temperature of the coils Lu, Lv, Lw of each phase is actually maximum, the location where the temperature sensor 30a is away from the location where the maximum temperature is reached. It is necessary to attach to. In this case, it is difficult for the coil temperature detection unit 47a to detect the accurate winding temperature of the coils Lu, Lv, Lw of each phase, and as a result, it may be difficult to protect the SR motor 3 from overheating. . Therefore, the coil temperature detection unit 47a corrects the winding temperature drop from the point where the winding temperature of the coils Lu, Lv, Lw reaches the position where the temperature sensor 30a is actually attached to correct winding. It becomes possible to detect the line temperature.

FIG. 2 shows an example of setting the current limit value by the coil temperature limit setting unit 47b.
This graph is a graph showing an example of setting current limit values for the coil temperatures of the coils Lu, Lv, and Lw when the vertical axis is the current value (A) and the horizontal axis is the winding temperature (° C.).
In the figure, 65 indicated by a broken line indicates an allowable limit line of the coils Lu, Lv, and Lw. For example, the maximum allowable current value is set to 75 (A). When the winding temperature of the coils Lu, Lv, and Lw reaches, for example, 180 ° C., the allowable current value gradually decreases. For example, when the winding temperature reaches 220 ° C., the supply current to the coils Lu, Lv, and Lw is cut off. , 0 (A) must be set.

Therefore, in the coil temperature limit setting unit 47b, for example, the maximum allowable current value is set to 75 (A) in consideration of the safety factor, but when the winding temperature of the coils Lu, Lv, Lw reaches 160 ° C., for example. The allowable current value is gradually decreased, and for example, the allowable current value is set to 0 (A) when reaching 200 ° C. (see the solid line in FIG. 2). That is, in the coil temperature limit setting unit 47b, two temperature set values 66a (for example, 160 ° C.) and 66b (for example, 200 ° C.) are provided, and when the temperature set value 66a is reached, the current limit value starts to be limited. When the value 66b is reached, the supply current is cut off.
As shown in FIG. 1, the current limit calculation unit 47 c uses the current limit value determined by the coil temperature limit setting unit 47 b based on the winding temperature data input from the coil temperature detection unit 47 a as the current limit determination unit 49. Is output.

The drive circuit overheat protection unit 48 applies the coils Lu, Lv, Lw of each phase of the SR motor 3 and the drive circuit 4 based on the temperature detected by the temperature sensor 30b attached in the vicinity of the first arm 41. The current limit value (drive circuit current limit value) that can be supplied is set. The drive circuit overheat protection unit 48 includes a circuit temperature detection unit 48a that detects the element temperature of the switching elements NH and NL constituting the first arm 41 based on a change in the resistance value of the temperature sensor 30b, and the switching elements NH and NL. Drive based on the circuit temperature limit setting unit 48b for setting the current limit value for the element temperature, the element temperature detected by the circuit temperature detection unit 48a, and the current limit value set by the circuit temperature limit setting unit 48b The current limit calculator 48c calculates a current limit value that can be supplied to the circuit 4.
Similarly to the coil temperature detection unit 47a, the circuit temperature detection unit 48a can correct the detection result of the temperature sensor 30b.

FIG. 3 shows an example of setting the current limit value by the circuit temperature limit setting unit 48b.
This graph is a graph showing an example of setting current limit values for the element temperatures of the switching elements NH and NL, where the vertical axis is the current value (A) and the horizontal axis is the element temperature (° C.).
In the figure, reference numeral 67 denotes an allowable limit line of the switching elements NH to 4L. For example, the maximum allowable current value is set to about 105 (A). When the element temperature of the switching elements NH to 4L reaches, for example, about 113 ° C., the allowable current value gradually decreases. For example, when the element temperature reaches 175 ° C., the supply current to the switching elements NH to 4L is cut off, that is, 0 It is necessary to make (A).

Therefore, the circuit temperature limit setting unit 48b sets, for example, the maximum allowable current value to about 78 (A) in consideration of the safety factor, and gradually when the element temperature of the switching elements NH and NL reaches, for example, about 96 ° C. For example, the allowable current value is set to 0 (A) when it reaches about 120 ° C. That is, in the circuit temperature limit setting unit 48b, two temperature setting values 68a (for example, 96 ° C.) and 68b (for example, 120 ° C.) are provided, and when the temperature setting value 68a is reached, the current limit value starts to be limited. When the value 68b is reached, the supply current is cut off.
As shown in FIG. 1, the current limit calculation unit 48 c sends the current limit value determined by the circuit temperature limit setting unit 48 b to the current limit determination unit 49 based on the element temperature data input from the circuit temperature detection unit 48 a. Output.

  The current limit determination unit 49 compares the current limit value input from the current limit calculation unit 47 c of the motor overheat protection unit 47 with the current limit value input from the current limit calculation unit 48 c of the drive circuit overheat protection unit 48. Based on the comparison result, any lower value is set as the true current limit value, and this current limit value is output to the current command value determination unit 51.

The current command value calculation unit 50 sets a target output of the SR motor 3 from an accelerator operation signal corresponding to a detection result of an accelerator pedal opening sensor or the like that detects an accelerator opening related to the driver's accelerator operation, for example. The target output is output to the current command value determination unit 51 as an accelerator opening signal.
The current command value determination unit 51 associates the current limit value input from the current limit determination unit 49 with the maximum output that can be set by the current command value calculation unit 50, and the current command value that is the current target output (request output) A current command value corresponding to the accelerator opening of the calculation unit 50 is calculated. The current command value is output to the current control unit 63 and the control map storage unit 57.

This will be described in more detail with reference to FIG. The graph is a graph showing changes in the current limit value relative to the accelerator opening when the vertical axis is the current limit value (current command value) (A) and the horizontal axis is the accelerator opening (%). In the following description, the case where the accelerator opening by the accelerator operation is fully closed is 0%, and the case where the accelerator is fully opened (maximum required output) is 100%.
As shown in the figure, the current command value determination unit 51 sets the current limit value determined by the current limit determination unit 49 as a value when the accelerator opening is 100%.

  A value obtained by multiplying the current limit value by the degree (%) of the accelerator opening is used as the current command value. By doing in this way, even if it is a case where a current limit value falls, the inclination gradient of the current command value until the accelerator opening degree reaches from 0% to 100% can be changed (the broken line in FIG. 4 and (See solid line). That is, the dead zone where the current command value does not change at all even if the driver performs the accelerator operation (depressing the accelerator) as the current limit value decreases as in the conventional case (see section A in FIG. 4). Will not form. For this reason, it is possible to finely control the current command value based on the accelerator opening in accordance with the current limit value.

  As shown in FIG. 1, the position detector 52 detects the rotational position of the rotor 12, that is, the rotational angle of the rotor 12 from a predetermined reference rotational position, based on the detection signal output from the resolver 17, and this rotational position. Is output to the rotation speed calculation unit 53 and the energization timing output unit 61. The rotation speed calculation unit 53 outputs the rotation speed (rotation speed) of the rotor 12 calculated based on the rotation position of the rotor 12 detected by the position detection unit 52 to the control map storage unit 57.

The map selection unit 56, for example, from among a plurality of advance angle maps 57a and energization angle maps 57b stored in the control map storage unit 57 in response to a predetermined map switching signal output from an external control device or the like. Then, a command signal instructing to select an appropriate advance angle map 57 a and energization angle map 57 b is output to the control map storage unit 57.
The control map storage unit 57 advances based on the current command value input from the current command value determination unit 51, the rotational speed input from the rotation speed calculation unit 53, and the command signal input from the map selection unit 56. The angle and energization angle are searched for a map and output to the energization timing output unit 61.

  The advance angle map 57a indicates that the energization start phase and the energization end phase for the coils Lu, Lv, and Lw of each phase of the SR motor 3 are predetermined phases (for example, an inductance increase start phase and a decrease). FIG. 5 is a map showing a predetermined correspondence relationship between an advance angle for changing from a start phase or the like to an advance side, a current command value corresponding to a target output, and a rotational speed, for example, as shown in FIG. As the current command value and the rotational speed increase according to the output, the advance angle changes in an increasing tendency. For example, the advance angle is proportional to the current command value (that is, the target output).

  The energization angle map 57b is a predetermined correspondence between energization angles (for example, values of electrical angle of 120 ° or more) for the coils Lu, Lv, and Lw of each phase and a current command value corresponding to the target output and the rotation speed. FIG. 6 is a map showing the relationship, for example, as shown in FIG. 6, the energization angle changes in an increasing trend as the current command value corresponding to the target output and the rotation speed increase. It is proportional to the value.

The energization timing output unit 61 is based on the rotational position of the rotor 12 input from the position detection unit 52, the advance angle and the energization angle input from the control map storage unit 57, and the second to fourth arms of the drive circuit 4. Each gate signal composed of pulses for controlling the on / off states of the switching elements 2H to 4L of 42 to 44 is generated and output to the gates of the transistors of the switching elements 2H to 4L, and the advance angle and the energization angle are PWM signals. Output to the output unit 64. As for the gate signal output to each switching element 2H-4L, on duty is made into predetermined value (for example, 100%) in the energization section according to advance angle and energization angle, for example.
The current detection unit 62 detects, for example, a winding current energized in the SR motor 3 based on a detection signal of each phase current (winding current) output from each current sensor 21, and the current of the winding current is detected. The detected value is output to the current control unit 63.

  The current control unit 63 performs feedback control of the winding current supplied to the SR motor 3, and includes, for example, a current feedback processing unit 63a and a PWM DUTY calculation unit 63b, and determines a current command value. Control is performed so that the deviation between the current command value input from the unit 51 and the detected value of the winding current input from the current detection unit 62 becomes zero.

The current feedback processing unit 63a controls and amplifies the deviation between the current command value for each phase and the detected value of the winding current, for example, by a PI (proportional integration) operation, and calculates a voltage command value for the winding voltage.
The PWM DUTY calculation unit 63b includes each gate including a pulse for controlling the on / off state of the switching elements NH and NL of the first arm 41 of the drive circuit 4 in accordance with the voltage command value calculated by the current feedback processing unit 63a. Calculate the duty of the signal.
For example, the PWMDUTY calculation unit 63b generates each gate signal (that is, PWM signal) by pulse width modulation based on the voltage command value and a carrier signal such as a triangular wave, and the duty of each gate signal, that is, the ON / OFF state of the gate signal. Calculate the ratio. Each gate signal and duty are output to the PWM signal output unit 64.

  The PWM signal output unit 64 includes pulses that control the on / off states of the switching elements NH and NL input from the current control unit 63 based on the advance angle and the energization angle input from the energization timing output unit 61. A gate signal is output to the gates of the transistors of the switching elements NH and NL. In the energization section corresponding to the advance angle and the energization angle, for example, the on-duty of the gate signal is a value calculated by the PWM Duty calculation unit 63b (that is, a value corresponding to the voltage command value).

Next, the energization state of the drive circuit 4 will be described based on FIGS. 7 (a), 7 (b), and 7 (c).
As shown in FIG. 7A, for example, when a winding current is supplied to the V-phase coil Lv, the switching element NH on the high potential side of the first arm 41 is turned on (opened), and the low potential Side switching element NL is turned off (closed). On the other hand, in the second to fourth arms 42 to 44, only the switching element 3L on the low potential side of the third arm 43 is turned on, and all the remaining switching elements are turned off. Then, the winding current flows from the switching element NH toward the low potential side of the battery 31 through the coil Lv and flows to the switching element 3L.

  Further, as shown in FIG. 7B, for example, when supplying a winding current to the W-phase coil Lw, the switching element NH on the high potential side of the first arm 41 is turned on (opened), The switching element NL on the low potential side is turned off (closed). On the other hand, in the second to fourth arms 42 to 44, only the switching element 4L on the low potential side of the fourth arm 44 is turned on, and all the remaining switching elements are turned off. Then, the winding current flows from the switching element NH toward the low potential side of the battery 31 through the coil Lw and flows to the switching element 4L.

  Furthermore, when supplying a winding current in the opposite direction to the V-phase coil Lv, for example, as shown in FIG. 7C, the switching element NL on the low potential side of the first arm 41 is turned on ( Open) and the switching element NH on the high potential side is turned off (closed). On the other hand, in the second to fourth arms 42 to 44, only the switching element 3H on the high potential side of the third arm 43 is turned on, and all the remaining switching elements are turned off. Then, the winding current flows from the switching element 3H toward the low potential side of the battery 31 through the coil Lv and flows to the switching element NL.

In this way, by sequentially switching each of the switching elements NH to 4L, the DC current supplied from the battery 31 is converted into a three-phase AC current, and an AC U-phase current, V is applied to the coils Lu, Lv, Lw of each phase. Supply phase current and W phase current.
Here, as shown in FIGS. 7A, 7B, and 7C, when current is supplied to the coils Lu, Lv, and Lw of each phase, the first arm 41 is always wound. Since the current flows, among the switching NH to 4L, the switching element NH, NL of the first arm 41 is most likely to rise in the element temperature. For this reason, the temperature sensor 30b is attached between the switching element NH and the switching element NL in the vicinity of the first arm 41 (on the first arm 41), so that the switching element having the highest temperature rises. It becomes possible to detect the element temperature.

Therefore, according to the first embodiment described above, each overheating is based on the winding temperature detected by the temperature sensor 30a attached to the SR motor 3 and the element temperature detected by the temperature sensor 30b attached to the drive circuit 4. The protection units 47 and 48 and the current limit determination unit 49 can determine the maximum current limit value that can prevent damage to the SR motor 3 and the drive circuit 4 when the temperature rises.
Further, in the current command value determining unit 51, the current limit value determined by the current limit determining unit 49 is made to correspond to the maximum output that can be set by the current command value calculating unit 50, and the degree of accelerator opening (% ) Is used as the current command value. For this reason, it becomes possible to finely control the current command value based on the accelerator opening degree in accordance with the current limit value without forming a dead zone for the accelerator operation (see section A in FIG. 4). Therefore, even if the SR motor 3 and the switching elements NH to 4L reach a predetermined temperature at which there is a risk of damage due to overheating, the driving of the SR motor 3 can be prevented from suddenly stopping without any previous contact, and good Accelerator operability can always be ensured.

Furthermore, the control map storage unit 57 can output the optimum advance angle and energization angle of the winding current to the energization timing output unit 61 according to the driving state of the SR motor 3, and the current control unit 63. Control can be performed so that the deviation between the current command value input from the current command value determination unit 51 and the detected value of the winding current input from the current detection unit 62 becomes zero. For this reason, while energizing each phase of the SR motor 3 by the advance angle and energization angle corresponding to the current command value and the rotational speed, the winding current feedback control is performed based on the current command value, and the apparatus configuration as in the prior art However, it is possible to obtain the maximum motor output at the time of temperature rise while suppressing an increase in cost by selecting a device having a complicated capacity or a large capacity.
And since the drive circuit 4 was comprised with the four arms 41-44, while the number of switching elements can be made into eight, the wiring of the drive circuit 4 connected to the SR motor 3 can be made into four. For this reason, it is possible to reduce the cost of the drive circuit 4.

  The temperature sensor 30a is attached to, for example, the V-phase coil Lv among the coils Lu, Lv, and Lw of the respective phases that are heat sources, and the temperature sensor 30b is connected to the switching element NH and the switching element of the first arm 41. By attaching the temperature sensor 30b to the NL, that is, by setting each temperature sensor 30a, 30b to a position where the amount of heat generation is large and a position where it is easy to assemble, the winding of the portion of the SR motor 3 that has the highest temperature is wound. The line temperature can be detected, and the element temperature of the highest part of the drive circuit 4 can be detected. For this reason, it is possible to reliably prevent the SR motor 3 and the switching elements NH to 4L from being damaged by overheating, and more reliably to obtain the maximum motor output when the temperature rises.

  In addition to this, each temperature sensor 30a, 30b is actually moved from the position where the winding temperature of the coils Lu, Lv, Lw is truly highest and the position where the element temperature of the switching elements NH, NL is truly highest. By correcting the temperature drop until reaching the installation position, it becomes possible to detect the winding temperature and the element temperature more accurately. For this reason, even when the layout of the temperature sensors 30a and 30b is limited, the temperature of the location desired to be detected can be accurately detected and the characteristics of the SR motor 3 can be improved.

Next, a second embodiment of the present invention will be described based on FIG. 8 with reference to FIGS. 7 (a), 7 (b), and 7 (c). In addition, the same aspect as 1st embodiment is attached | subjected and demonstrated (it is the same also in the following embodiment).
In the second embodiment, the control device 70 includes a drive circuit 71 connected to the SR motor 3 and a driver unit 72 that controls the drive circuit 71. The drive circuit 71 is a power source. A smoothing capacitor 32 and four arms 41, 42, 43, 44 in which switching elements are arranged in a battery 31 are connected in parallel, and each SR motor 3 serves as a heat source. The temperature sensor 30a is attached to any one of the phase coils Lu, Lv, Lw (on the V-phase coil Lv in the second embodiment), and the four arms 41, 42, 43, 44. Among them, the point that the temperature sensor 30b is attached in the vicinity of the first arm 41 to which the neutral point 46 is connected, the basic configuration of the driver unit 72, etc. are the same as those in the first embodiment. Is the same as that.

Here, in the second embodiment, the driver unit 72 performs on / off control of the switching elements NH and NL of the first arm 41 and PWMs the switching elements 2H to 4L of the second to fourth arms 42 to 44. Configured to control.
For this reason, the energization timing output unit 61 is connected to the gates of the switching elements NH and NL of the first arm 41. The PWM signal output unit 64 is connected to the gates of the switching elements 2H to 4L of the second to fourth arms 42 to 44.

The basic energization state of the drive circuit 4 in the control device 70 is the same as that in FIGS. 7A, 7B, and 7C.
That is, for example, when supplying a winding current to the V-phase coil Lv, the switching element NH on the high potential side of the first arm 41 is turned on as shown in FIG. When the switching element 3L is turned on, a current flows through the V-phase coil Lv.
As shown in FIG. 7B, when supplying a winding current to the W-phase coil Lw, the switching element NH on the high potential side of the first arm 41 is turned on, and the switching element 4L is turned on by PWM control. When turned on, a current flows through the W-phase coil Lw.
As shown in FIG. 7C, when a current in the direction opposite to that in FIG. 7A is passed through the V-phase coil Lv, the switching element NL on the low potential side of the first arm 41 is turned on, The switching element 3H is turned on by PWM control.

  Therefore, according to the second embodiment described above, in addition to the same effects as those of the first embodiment described above, the switching elements 2H to 4L of the second to fourth arms 42 to 44 are PWM-controlled, so that the switching elements The cooling effect can be improved by distributing the frequency of the open / close control of the switch and the switching loss. Further, an inexpensive switching element connected to the energization timing output unit 61 can be used.

Next, a third embodiment of the present invention will be described with reference to FIG.
In the third embodiment, the control device 80 includes a drive circuit 81 connected to the SR motor 3 and a driver unit 82 that controls the drive circuit 81. The configuration and the like are the same as those in the first embodiment.
Here, the drive circuit 81 of the third embodiment is configured to include a switching circuit 83 including a switching element having a transistor such as an FET, a diode, and a smoothing capacitor 32.

The switching circuit 83 includes a high-side arm in which high-side switching elements UH, VH, WH and low-side diodes DUL, DVL, DWL are connected in series to the battery 31 for each phase, and low-side switching for each phase. Elements UL, VL, WL and high side diodes DUH, DVH, DWH are provided with a low side arm connected in series to battery 31.
In the high-side arm, the drains of the high-side switching elements UH, VH, and WH are connected to the positive terminal of the battery 31, and the low-side diodes DUL, DVL, DWL are connected to the high-side switching elements UH from the negative terminal of the battery 31. , VH, WH toward the source.

In the low side arm, the sources of the low side switching elements UL, VL, WL are connected to the negative side terminal of the battery 31, and the high side diodes DUH, DVH, DWH are connected to the drains of the low side switching elements UL, VL, WL. The forward direction is directed toward the positive terminal of the battery 31.
Note that each of the switching elements NH, NL, 2H to 4L has a configuration in which a transistor and a diode that prevents backflow between the drain and source of the transistor are connected in parallel to the battery 31.

In addition, one end of each phase coil Lu, Lu, coil Lv, Lv, and coil Lw, Lw is connected to the source of each high-side switching element UH, VH, WH, and the other end is each low-side switching element. It is connected to the drains of UL, VL, WL.
Further, a PWM signal output unit 64 is connected to the gates of the high-side switching elements UH, VH, and WH, and an energization timing output unit 61 is connected to the gates of the low-side switching elements UL, VL, and WL. It is connected.

One current sensor 21 is provided between each low-side switching element UL, VL, WL and each phase coil Lu, Lv, Lw.
In the SR motor 3, a temperature sensor 30a is attached to any one of the coils Lu, Lv, and Lw of each phase that is a heat generation source (on the W-phase coil Lw in the third embodiment). In addition, the temperature sensor 30 b is attached to the drive circuit 81 at the approximate center of the switching circuit 83.

The switching circuit 83 of the drive circuit 81 configured as described above is in accordance with the gate signal input from the energization timing output unit 61 and the PWM signal output unit 64 of the driver unit 82 when the SR motor 3 is driven. The on / off state of each switching element UH, UL, VH, VL, WH, WL is switched for each phase. Thereby, the direct current supplied from the battery 31 is converted into a three-phase alternating current, and the alternating U-phase current, V-phase current, and W-phase current are supplied to the coils Lu, Lv, and Lw of each phase.
Therefore, according to the above-described third embodiment, the same effects as those of the first embodiment described above can be achieved.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
In the above-described embodiment, the SR motor 3 is wound with three-phase (U-phase, V-phase, W-phase) coils Lu, Lv, Lw, and the coils Lu, Lv of each phase. , Lw have been described for the case where the pair of stator salient poles 14 facing each other in the radial direction is formed by winding a winding. However, the number of coils and the number of phases are not limited to this.

Furthermore, in the first embodiment and the second embodiment described above, the case where each of the drive circuits 4 and 71 is configured by four arms 41 to 44 has been described, but the number of arms is not limited thereto.
And in the above-mentioned embodiment, about the case where the temperature sensor 30a is attached to any one place on the coils Lu, Lv, Lw of each phase of the SR motor 3, and the temperature sensor 30b is attached to the drive circuits 4, 71, 81. explained. However, the present invention is not limited to this, and a temperature sensor may be provided only in one of the SR motor 3 and the drive circuits 4, 71, 81.

It is a block diagram which shows the control apparatus of SR motor in 1st embodiment of this invention. It is a graph which shows the example of a setting of the current limit value with respect to the coil | winding temperature of the coil in embodiment of this invention. It is a graph which shows the example of a setting of the current limit value with respect to the element temperature of the switching element in embodiment of this invention. It is a graph which shows the change of the current limit value with respect to the accelerator opening in embodiment of this invention. It is a graph which shows the advance map in embodiment of this invention. It is a graph which shows the conduction angle map in embodiment of this invention. It is explanatory drawing of the electricity supply state of the drive circuit in 1st embodiment of this invention, and 2nd embodiment. It is a block diagram which shows the control apparatus of SR motor in 2nd embodiment of this invention. It is a block diagram which shows the control apparatus of SR motor in 3rd embodiment of this invention.

Explanation of symbols

1, 70, 80 Control device 3 Switched reluctance motor 4, 71, 81 Drive circuit 5, 72, 82 Driver unit 11 Stator 12 Rotor 14 Stator salient pole 16 Rotor salient pole 21 Current sensor 30a, 30b Temperature sensor 31 Battery (power source )
41 First arm (arm)
42 Second arm (arm)
43 Third arm (arm)
44 Fourth arm (arm)
46 Neutral point 47 Motor overheat protection part 47a Coil temperature detection part 47b Coil temperature limit setting part 47c Current limit calculation part (motor limit value setting means)
48 drive circuit overheat protection unit 48a circuit temperature detection unit 48b circuit temperature limit setting unit 48c current limit calculation unit (drive circuit limit value setting means)
49 Current limit determination unit (current limit value setting means)
50 Current command value calculation unit (target output setting means)
51 Current command value determining unit (current command value generating means)
52 Position detection unit (rotation position detection means)
53 Rotational speed calculation unit (rotational speed detection means)
57 Control map storage unit (energization state setting means)
57a Lead angle map 57b Energization angle map 61 Energization timing output unit (energization timing output means)
62 Current detection unit (current detection means)
63 Current controller (pulse width modulation signal generating means)
64 PWM signal output section (pulse width modulation signal output means)
83 Switching circuit Lu, Lv, Lw Coil NH, NL, 2H to 4L Switching element UH, VH, WH High side switching element UL, VL, WL Low side switching element DUH, DVH, DWH High side diode DUL, DVL, DWL Low Side diode

Claims (4)

A switched reluctance motor having a rotor formed with a rotor salient pole and a stator having a stator salient pole formed with a plurality of coils wound around the stator salient pole;
A drive circuit that switches a current supply line from a power source to the plurality of coils using a plurality of switching elements, and controls an energization state of the plurality of coils;
A plurality of temperature sensors respectively provided in the switched reluctance motor and the drive circuit;
Motor limit value setting means for setting a motor current limit value that can be supplied to the switched reluctance motor based on a temperature detected by a temperature sensor provided in the switched reluctance motor;
Drive circuit limit value setting means for setting a drive circuit current limit value that can be supplied to the drive circuit based on a temperature detected by a temperature sensor provided in the drive circuit;
A current limit that sets the lower value of the motor current limit value set by the motor limit value setting means or the drive circuit current limit value set by the drive circuit limit value setting means as a true current limit value Value setting means,
Target output setting means for setting a target output of the switched reluctance motor;
Generates a current command value based on the target output when the true current limit value set by the current limit value setting means corresponds to the maximum output of the target output set by the target output setting means Current command value generating means for performing,
Rotational position detecting means for detecting the rotational position of the rotor;
A rotational speed detecting means for detecting a rotational speed of the rotor based on the rotational position detected by the rotational position detecting means;
An energization state for setting an energization angle and an advance angle for energization of the switched reluctance motor according to the current command value generated by the current command value generation unit and the rotation speed detected by the rotation speed detection unit Setting means;
An energization timing output that outputs an energization timing signal to the switched reluctance motor based on the rotation position detected by the rotation position detection unit and the energization angle and the advance angle set by the energization state setting unit Means,
Current detection means for detecting a current supplied to the switched reluctance motor as a current detection value;
A pulse width modulation signal generation means for generating a pulse width modulation signal based on a deviation between the current command value generated by the current command value generation means and the current detection value detected by the current detection means;
A pulse width modulation signal output means for outputting the pulse width modulation signal generated by the pulse width modulation signal generation means based on the energization timing signal output by the energization timing output means;
In the motor limit value setting means, a first motor temperature at which the motor current limit value starts to decrease and a second motor temperature at which the motor current limit value is set to 0 amperes are set in advance,
In the drive circuit limit value setting means, a first drive circuit temperature at which the drive circuit current limit value starts to be lowered and a second drive circuit temperature at which the drive circuit current limit value is set to 0 amperes are set in advance.
The drive circuit sequentially turns on the plurality of coils according to the energization timing signal output from the energization timing output means and the pulse width modulation signal output from the pulse width modulation signal output means. Switched reluctance motor control device characterized by switching. Connecting one end of the plurality of coils to form a neutral point;
The drive circuit is configured by connecting a plurality of arms each having two switching elements connected in series to each other in parallel to the power source,
One of the plurality of arms and connecting the neutral point between the two switching elements;
The other arm of the plurality of arms, and connecting the other ends of the plurality of coils one by one between the two switching elements,
One of the one arm to which the neutral point is connected or the other arm to which the other ends of the plurality of coils are connected is connected to the energization timing output means, and the other is 2. The switched reluctance motor control device according to claim 1, wherein the control device is connected to a pulse width modulation signal output means.   The plurality of temperature sensors are provided on the coil wound around the stator salient pole, and are provided in the vicinity of the one arm to which the neutral point is connected. Item 3. The switched reluctance motor control device according to Item 2. While correcting the temperature difference generated between the location where the temperature sensor is provided and the location where the maximum temperature of the coil is detected, the temperature detected by the temperature sensor provided on the coil,
A temperature detected by a temperature sensor provided in the vicinity of the one arm is corrected for a temperature difference generated between a location where the temperature sensor is provided and the switching element of the one arm. The control device for a switched reluctance motor according to claim 3.

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