JP2002305891A - Drive for brushless dc motor for electric vehicle drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive for a brushless DC motor for electric vehicle which can suppress the temperature rise of an armature coil or a switch circuit. SOLUTION: In the drive for the brushless DC motor 1, which PWM-controls the drive current flowing to the armature coils Lu-Lw relative to the throttle signal outputted by a throttle sensor 15 and the control lead angle of the changeover angle, in switching the phase of the armature coil to which the drive current flows to the throttle signal, the value of the throttle signal is modified into a value smaller than the actual value when the temperature of the armature coils Lu-Lw or the temperature of the switch circuit 10 is over a set value. Hereby, the opening of the throttle detected at abnormal rise of the temperature is made small apparently, thereby suppressing the temperature rise of the armature coils Lu-Lw and the switch circuit 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an electric scooter,
The present invention relates to a drive device for a brushless DC motor for an electric vehicle used as a drive source for an electric vehicle such as an electric vehicle.

[0002]

2. Description of the Related Art As is well known, a brushless DC motor includes a rotor having a magnet field and a stator having three or more phased armature coils. The rotor is rotated by switching the excitation phase of the armature coil accordingly.

A driving device for driving this type of motor includes a position detector for detecting a rotational angle position of a rotor with respect to a stator, and a DC power source and an armature for switching a phase in which a driving current flows from a DC power source to an armature coil. A switch circuit provided between the coil, a speed adjusting member operated when adjusting the rotation speed of the electric motor, and a displacement amount of the speed adjusting member detected as a throttle opening to correspond to the throttle opening. It is composed of a throttle sensor that outputs a throttle signal of a magnitude, and a controller that controls a switch circuit to switch a phase in which a drive current flows according to the output of the position detector to rotate the rotor. The controller includes a PWM control unit that controls the switch circuit so that the drive current is a PWM waveform current having a duty ratio calculated with respect to the throttle signal, and a switching angle of a phase through which the drive current flows with respect to the throttle signal. Control lead angle control means for performing control so as to shift by the calculated control lead angle with respect to a reference switching angle determined by the output of the position detector.

Here, the duty ratio of the drive current indicates the ratio of the ON time to the ON / OFF cycle of the drive current. The time when the drive current flows is ton, the time when the drive current is zero is toff, and the on / off cycle is T (= ton + toff)
, The duty ratio DF is DF = (ton / T)
× 100 [%] is defined.

[0005] In an electric vehicle, the rotational speed of the electric motor is adjusted by displacing a speed adjusting member such as an accelerator grip or an accelerator pedal. However, in order to improve the driving feeling of the vehicle and perform smooth driving, Rather than controlling the duty ratio DF of the drive current only for the displacement amount (throttle opening) α of the speed adjusting member, the rate of change of the duty ratio DF for the speed adjusting member depends on the rotation speed N [rpm] of the motor. The duty ratio DF is controlled with respect to both the throttle opening α and the rotation speed N so as to change the rotation speed.

When the duty ratio DF is controlled with respect to the throttle opening α and the rotation speed N as described above, the relationship between the throttle opening α, the rotation speed N, and the duty ratio DF of the driving current is determined. The given three-dimensional map is stored in the ROM, and using this map, the CPU uses the duty ratio DF for the rotation speed N and the throttle opening α.
Is calculated, and on / off control of the switch element of the switch circuit is performed so that the drive current is intermittently operated at the calculated duty ratio DF.

In a brushless DC motor, a switching angle (electric angle) for switching a phase of an armature coil through which a driving current flows is shifted by a predetermined angle with respect to a theoretical switching angle determined by a mechanical configuration of the motor. Let me. The phase difference between the switching angle of the phase through which the drive current flows and the theoretical switching angle is called a control advance angle γ, and the control advance angle γ is generally set to the advance side.

In the brushless DC motor, the generated torque and the maximum rotational speed change according to the control advance angle γ. When the control advance angle γ is set so as to increase the torque, the maximum rotational speed decreases, and the control advance angle γ decreases. As the angle is advanced, the maximum rotation speed increases, but the generated torque decreases.

Normally, when a brushless DC motor is used as a drive source of an electric vehicle, a control advance angle γ at which a sufficiently large torque can be obtained at a low speed is set as a normal control advance angle γo, and rotation is performed. In the region where the speed exceeds the set value, the control advance angle γ is advanced with respect to the normal control advance angle γo in accordance with the increase in the rotational speed, and in the region where the rotational speed exceeds the set advance end rotational speed, the control advance proceeds. The angle advance amount is kept at the maximum value.

In the case of performing the control advance angle control as described above, a three-dimensional map giving the relationship between the displacement amount (throttle opening) α of the speed adjusting member, the rotational speed N, and the control advance angle γ is used. The control advance angle γ is calculated for the detected value of the throttle opening and the detected value of the rotational speed using this map, and the control advance angle of the electric motor is calculated as the calculated control advance angle. Control to make them equal.

As described above, when the control is performed such that the control advance angle γ is advanced beyond the normal control advance angle γo in the region where the rotational speed exceeds the set value, the speed advancement of the speed adjusting member is performed on an uphill or the like. When the motor is operated with the maximum displacement (full throttle), the control lead angle γ is maintained at the maximum value, and the drive current of the motor exceeds the rated value. State. If this condition continues for a long time,
The temperature of the armature coil and the semiconductor switch element of the switch circuit rises and exceeds an allowable value, which may be damaged.

Therefore, a temperature sensor for detecting the temperature of the driving device or the armature coil is provided, and when an abnormal temperature rise is detected by the temperature sensor, the drive current is reduced by reducing the upper limit value of the duty ratio of the drive current. By limiting the current, temperature rise suppression control for suppressing the temperature rise is performed.

However, even if the drive current is limited when the temperature rises, if the control advance angle is still advanced, a large amount of reactive current flows, so that the rotational speed is greatly reduced and the travel speed is limited. Occurs. In practice, it is desirable to minimize the decrease in the rotation speed when performing the temperature rise suppression control.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 8-265919, the temperature of an armature coil and the temperature of a component of a switch circuit for turning on / off a drive current flowing through the armature coil are detected to detect the temperature. It has been proposed to perform control for retarding the control advance angle and control for reducing the duty ratio of the drive current when an abnormal rise is detected.

If the control advance angle is retarded when an abnormal temperature rise occurs, the drive current decreases, so that the temperature rise of the armature coil and the switch element of the switch circuit can be suppressed. In addition, the method of reducing the drive current by retarding the control advance angle takes a smaller rotational speed than the method of reducing only the duty ratio of the drive current without delaying the control advance angle. Can be reduced, so that it is possible to prevent the feeling of operation from being deteriorated during the temperature suppression control.

If the retard amount of the control advance angle is too large, the reactive current becomes excessively large, which is not preferable. However, the control for retarding the control advance angle and the control for reducing the duty ratio of the drive current are used together. By doing so, it is not necessary to increase the retard amount of the control advance angle so much, and it is possible to prevent the reactive current from becoming excessive.

[0017]

As described above, in a brushless DC motor for an electric vehicle, the temperature of an armature coil and the temperature of a switch element of a switch circuit for switching an excitation phase of the armature coil abnormally rise. In order to prevent this, it is preferable to perform control to retard the control advance angle and reduce the duty ratio of the drive current when an abnormal rise in temperature is detected.

In order to perform such control, the duty ratio and the control progress are made with respect to three variables of the detected value of the temperature of the armature coil and the switch element of the switch circuit, the throttle opening, and the rotation speed of the motor. It is necessary to determine the corner. In this case, a four-dimensional map that gives a relationship between the detected value of the temperature, the throttle opening, the rotation speed of the motor, and the duty ratio, and the detected value of the temperature, the throttle opening, the rotation speed of the motor, It is conceivable to calculate the duty ratio and the control lead angle using a four-dimensional map that gives a relationship between the control lead angle and the control lead angle. It is difficult to perform good control.

An object of the present invention is to provide a highly practical drive device for a brushless DC motor for an electric vehicle, which can easily perform a control for suppressing a temperature rise of an armature coil and a switch element.

[0020]

SUMMARY OF THE INVENTION The present invention detects the rotational angular position of a rotor of a brushless DC motor for driving an electric vehicle having a rotor having a magnet field and a stator having a multi-phase armature coil. A position detector, a switch circuit provided between the DC power supply and the armature coil for switching a phase in which a drive current flows from the DC power supply to the armature coil, and a switch circuit operated when adjusting the rotation speed of the motor. A speed adjusting member, a throttle sensor that detects a displacement amount of the speed adjusting member as a throttle opening and outputs a throttle signal of a magnitude corresponding to the throttle opening, and an output of a position detector to rotate the rotor. A brushless DC motor for driving an electric vehicle, comprising: a controller that controls a switch circuit to switch a phase through which a drive current flows according to the driving. To target location.

[0021] The controller may control the drive current by a PWM having a duty ratio calculated with respect to the throttle signal.
PWM for controlling a switch circuit to generate a waveform current
Control means and control advance angle control for controlling the phase change angle of the phase in which the drive current flows to be shifted by a control advance angle calculated for the throttle signal with respect to a reference change angle determined by the output of the position detector. Means.

In the present invention, a temperature detector for detecting the temperature of a component requiring monitoring selected from components that generate heat when a drive current flows, and a temperature detected by the temperature detector being lower than a set value Sometimes, the value of the throttle signal output from the throttle sensor is kept as it is, and when the detected temperature exceeds the set value, the value of the throttle signal obtained from the throttle sensor is corrected to a smaller value as the detected temperature is higher. Thus, the throttle signal correcting means for correcting the value of the throttle signal according to the detected temperature is provided.

The PWM control means and the control lead angle control means are configured to calculate the duty ratio and the control lead angle with respect to the value of the throttle signal corrected by the throttle signal correction means, respectively.

As described above, the value of the throttle signal is corrected with respect to the temperature detected by the temperature detector, the duty ratio is calculated in the PWM control using the corrected throttle signal, and the control advance in the control advance angle control is performed. If the calculation of the angle is performed, the duty ratio and the control lead angle can be controlled with respect to the detected temperature only by performing a very simple calculation, so that the temperature suppression control can be easily performed. .

When there are a plurality of the above-mentioned monitored parts, a plurality of the temperature detectors for detecting the temperatures of the plurality of the monitored parts are provided, and the plurality of the monitored parts detected by the plurality of the temperature detectors are provided. If all of the temperatures of the components requiring monitoring are lower than the set values set for each of the components requiring monitoring, the value of the throttle signal obtained from the throttle sensor remains unchanged, and the temperature of any component requiring monitoring becomes It is preferable that the throttle signal correcting means is configured to correct the value of the throttle signal to a smaller value as the detected temperature is higher when it is detected that the set value becomes equal to or more than the set value set for the throttle signal.

It is preferable to select at least an armature coil and a switch circuit as the above-mentioned monitored parts.

When the armature coil and the switch circuit are selected as components requiring monitoring, a temperature detector for the armature coil for detecting the temperature of the armature coil and a temperature detector for the switch circuit for detecting the temperature of the switch circuit And a container. In this case, the throttle signal correcting means determines that the temperature detected by the armature coil temperature detector is lower than a set value set for the armature coil, and that the temperature detected by the switch circuit temperature detector is a switch. When the value is lower than the set value set for the circuit, the value of the throttle signal obtained from the throttle sensor is kept as it is, and the temperature detected by the armature coil temperature detector is set to the set value set for the armature coil. When the temperature becomes higher than the above, or when the temperature detected by the switch circuit temperature detector becomes equal to or higher than a set value set for the switch circuit, the value of the throttle signal becomes smaller as the detected temperature becomes higher. It is preferable to configure to correct the value.

In this case, the armature coil temperature detector is
As a configuration in which the temperature-sensitive resistance elements of the number of phases provided to detect the temperature of the armature coil of each phase are connected in parallel, the multi-phase It is preferable to detect the average temperature of the armature coil.

When the armature coil temperature detector is configured to detect only the temperature of the armature coil of a specific phase, the motor is locked and the temperature of the specific armature coil rises abnormally. However, when the temperature rises, it may not be possible to detect an abnormal rise in the temperature. However, as described above, the temperature-sensitive resistance elements for the number of phases are provided, and If the average temperature of the multi-phase armature coil is detected from the parallel combined resistance value, even if the temperature of a specific armature coil rises abnormally, a temperature detection signal reflecting the abnormal rise in temperature is obtained. So you can
The armature coil can be properly protected.

In order to detect the temperature of the switch circuit, the temperature of the heat sink to which the switch elements constituting the switch circuit are attached may be detected. The temperature detector for the switch circuit can also be constituted by a temperature-sensitive resistance element.

The throttle signal correcting means includes a throttle signal value Vht output from the throttle sensor and a throttle signal value Vmin when starting the DC motor.
And the correction rate d (<100) [%], the correction value Vth ′ of the throttle signal is calculated by the following equation: Vth ′ = (Vth−Vmin)
) × d / 100 + Vmin.

In this case, the correction rate d is set to 100 [%] in a range where the detected temperature indicates a value lower than the set value.
In the range where the detected temperature is equal to or higher than the set value, the correction rate d is calculated using the correction rate calculation map that defines the relationship between the temperature and the correction rate so as to decrease as the temperature increases. can do.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, reference numeral 1 denotes a rotor 2 and a stator 3
And an outer rotor type brushless DC motor. The rotor 2 includes a flywheel 201 formed of a substantially cup-shaped ferromagnetic material, and a flywheel 201.
And a permanent magnet 202 attached to the inner periphery of the peripheral wall portion.
A pole magnet field 203 is configured.

The magnet field is not limited to two poles, but can be generally formed as 2 m poles (m is an integer of 1 or more).

In the illustrated example, the normal rotation direction of the rotor 2 is the direction of the arrow CCL (counterclockwise in FIG. 1).

The stator 3 has a stator core 301 having three teeth Pu to Pw radially protruding from an annular yoke.
And three-phase armature coils Lu to Lw wound around tooth portions Pu to Pw of the stator core, respectively.
The armature coils Lu to Lw are connected in a three-phase star connection. An outer peripheral portion of each tip of the teeth Pu to Pw of the stator core 301 is a stator magnetic pole 302, and these stator magnetic poles are opposed to the magnet field 203 via a predetermined gap.

In the illustrated example, the stator core has three poles. However, when the number of phases of the armature coils provided on the stator is three, the stator core generally has 3n (n is an integer of 1 or more) pieces. , And a configuration in which a three-phase armature coil is wound around the 3n teeth.

The flywheel 201 is provided with a boss (not shown) at the center of the bottom wall thereof, and the boss is connected to the driving wheel of the electric vehicle directly or via a reduction gear.

In order to detect the rotational angle position of the rotor 2 with respect to the stator 3, three-phase position detectors hu to hw are attached to the stator core 301.

Each position detector is arranged at an appropriate position according to the conduction angle (electrical angle) of the drive current flowing through the armature coil of each phase. For example, the position where the no-load induced voltage induced in each of the armature coils Lu to Lw with the rotation of the rotor 2 reaches a peak (the magnetic flux flowing from the magnet field 203 through the teeth around which the armature coils of each phase are wound). "180-degree switching control" in which a drive current flows through the armature coil of each phase in a section of 90 degrees (electrical angle) before and after the position where the zero passes through the zero point.
Is performed to rotate the motor, the tooth portions Pu to P around which the three-phase armature coils Lu to Lw are wound, respectively.
Position detectors for each phase are mounted so as to detect the rotation angle position of the rotor when the center position of the magnetic pole portion at the tip of w coincides with the center position of each magnetic pole of the magnet field of the rotor 2.

As shown, when armature coils Lu to Lw are wound around three tooth portions Pu to Pw, respectively, and Hall ICs are used as the position detectors hu to hw, the tooth portions Pu and Pw are used. The position detector h is located at a position advanced by 90 degrees in electrical angle with respect to the center of each magnetic pole of Pv and Pw.
w, hu, and hv are arranged, and a switching angle of a driving phase (a phase of an armature coil through which a driving current flows) determined by outputs of these position detectors is set as a reference switching angle. The control advance angle is calculated so that the actual switching angle is advanced or retarded.

Reference numeral 10 denotes a switch circuit provided between the armature coils Lu to Lw and the DC power supply 11 for switching the excitation phase of the armature coils. This switch circuit is composed of upper-stage switch elements 10u to 10w each having one end commonly connected.
And an upper switch element 10u having one end connected to the other end of each of the upper switch elements and a lower switch element 10x to 10z commonly connected to the other end. And a common connection point at one end of the switch element and lower switch elements 10x to 10w.
The common connection point at the other end of w is connected to the positive terminal and the negative terminal of the DC power supply 11, respectively.

As the switch elements constituting the switch circuit, any switch elements that can be controlled to be on and off, such as MOSFETs, power transistors, and IGBTs, can be used. In the illustrated example, each switch element is a MOS.
It consists of FET.

Since a regenerative current flows during braking of the electric vehicle,
A feedback diode 12u is connected to each of the upper switch elements 10u to 10w and the lower switch elements 10x to 10z.
To 12w and 12x to 12z are connected. When MOSFETs are used as the switch elements as shown in the figure, a parasitic diode formed between the drain and source of the FET can be used as these feedback diodes.

The illustrated DC power supply 11 comprises a battery B and capacitors C1 connected to both ends of the battery.

In order to control the switch circuit 10, a controller 13 having a microcomputer and an input / output interface, and switch elements 10u to 10w of the switch circuit in accordance with a signal given from the controller 13.
And 10x to 10z drive signals (signals for turning on the switch elements) Su to Sw and Sx to S, respectively.
and a driver circuit 14 for providing position detection signals Hu to Hw obtained from the position detectors hu to hw, respectively.
w is input to the controller 13.

Reference numeral 15 denotes a throttle sensor for detecting a displacement amount of a speed adjusting member such as an accelerator grip or an axel petal for adjusting the speed of the electric vehicle as a throttle opening α. The illustrated throttle sensor 15 includes a potentiometer in which a movable contact 15a is connected to a speed adjusting member. A DC constant voltage E obtained from a constant voltage DC power supply circuit (not shown) is applied to both ends of a potentiometer constituting the throttle sensor 15, and is proportional to the throttle opening α between the movable contact 15a of the potentiometer and the ground. The throttle signal Vα is obtained. A throttle signal obtained from the throttle sensor 15 is input to the controller 13. The throttle signal is converted into a digital value Vth by an A / D converter provided in the controller 13 and is converted into a digital signal Vth.
Read by PU.

In the present invention, a temperature detector is provided for detecting the temperature of a component requiring monitoring selected from components that generate heat when a drive current flows.
Usually, at least the armature coil and the components (switch elements) of the switch circuit 10 are selected as the monitoring required components. In the illustrated example, the temperature-sensitive resistance elements Rtu to Rtw having a negative temperature coefficient or a positive temperature coefficient are detected so as to detect the respective temperatures of the three-phase armature coils Lu to Lw. Thermally coupled. The temperature-sensitive resistance elements Rtu to Rtw are connected in parallel with each other, and these temperature-sensitive resistance elements constitute a temperature detector for an armature coil.

In order to detect the temperature of the switch circuit 10 (the temperature of the switch element), a heat-sensitive resistor R is attached to a heat sink on which the constituent elements of the switch circuit 10 are mounted.
ts are thermally coupled, and the temperature-sensitive resistance element Rts forms a switch circuit temperature detector. A detection signal (change in resistance value in this example) obtained from the switch circuit temperature detector is input to the controller 13 together with a detection signal obtained from the armature coil temperature detector.

The controller 13 is provided with a voltage application circuit for applying a constant voltage to both ends of a parallel circuit of the temperature-sensitive resistance elements Rtu to Rtw constituting the armature coil temperature detector. To Rtw (voltage in proportion to the parallel composite value of the temperature-sensitive resistance elements Rtu to Rtw) is read into the CPU of the microcomputer through the A / D converter as a temperature detection signal.

Similarly, a voltage application circuit for applying a constant voltage to both ends of the temperature-sensitive resistance element Rts for detecting the temperature of the switch circuit is provided in the controller.
Is read into the CPU through the A / D converter as a temperature detection signal.

The controller 13 configures various means necessary for controlling the motor by causing a microcomputer to execute a predetermined program. FIG. 2 shows the overall configuration of the embodiment of FIG. 1 including the configuration of various function realizing means realized by the controller 13 causing the microcomputer to execute a predetermined program.

The controller 13 calculates the rotation speed N of the electric motor by measuring, for example, the intervals of generation of the rectangular wave-like position detection signals generated by the position detectors hu to hw, and calculates the rotation speed N and the throttle signal. (Digital value) Vth, the duty ratio DF of the drive current supplied to the armature coil of the brushless DC motor 1 based on the throttle opening information obtained from the throttle opening information, and the control lead angle (phase of the armature coil flowing the drive current) Is calculated, and a phase difference (γ) between the actual switching angle at which the switching is performed and the reference switching angle determined by the arrangement of the position detector is calculated. The calculation of the duty ratio DF and the control advance angle γ are performed by a three-dimensional map for calculating the duty ratio, which gives the relationship between the rotation speed N, the throttle opening, and the duty ratio DF, and the rotation speed N, the throttle opening, and the control advance angle, respectively. This is performed by an interpolation method using a three-dimensional map for calculating a control lead angle which gives a relationship with γ (all maps are stored in the ROM).

The rotation speed detecting means 13a for detecting the rotation speed of the electric motor by the process of calculating the rotation speed among the programs executed by the microcomputer constituting the controller 13 is realized. The duty ratio calculating means 13b calculates the duty ratio of the drive current with respect to the value of the throttle signal and the rotational speed by the process of calculating the duty ratio using the duty ratio calculation map.
Is configured.

Further, the control lead angle calculating means 13c is formed by calculating the control lead angle with respect to the throttle signal using the control lead angle calculation map.

The controller 13 also has a position detector hu.
, The excitation phase determining means 13d for determining the phase in which the drive current flows based on the output signals of the values .about.hw. The excitation phase determining means 13d provides a drive signal to a predetermined switch element of the switch circuit 10 to the armature coil of the determined phase at a timing having the control advance angle calculated by the control advance angle calculating means 13c. A command signal for giving a command is given to the driver circuit 14. The driver circuit 14 supplies a drive signal to a predetermined switch element according to the command signal.

In order to make the waveform of the drive current supplied to the electric motor 1 a PWM waveform that is intermittent at the duty ratio calculated by the duty ratio calculation means 13b, the drive circuit 14 supplies a drive signal to the switch element of the switch circuit 10 Modulation means 13e for PWM-modulating the signal is provided.

FIGS. 3A to 3I show waveforms of a position detection signal when the brushless DC motor shown in FIG. 1 is driven by performing a 180-degree switching control, and each switch element of the switch circuit 10. FIG. 4 is a waveform diagram showing on / off operation waveforms. 3A to 3C show position detection signals Hu to Hw generated by the position detectors hu to hw, respectively.
FIGS. 3D to 3F respectively show the upper switch elements 10 u to 10 w of the switch circuit 10 when the angle at which the phase of the armature coil for flowing the drive current is switched is set as a reference switching angle. Of FIG. FIGS. 3G to 3I show the on / off operations of the lower switch elements 10x to 10z of the switch circuit 10, respectively.

The excitation phase determining means 13d performs a logical operation on the position detection signals shown in FIGS. 3 (A) to 3 (C) so that each switch element of the switch circuit 10 is turned on and off. Is determined, and a drive signal is applied to each switch element in a section where each switch element is turned on.

In the example shown in the figure, the modulating means 13e performs a PWM control of the driving current. In the illustrated example, the driving signal supplied from the driver circuit 14 to the lower switch elements 10x to 10z is converted by the duty ratio calculated by the duty ratio calculating means 13b. The signal is modulated into an intermittent PW waveform, and the lower switch element is turned on and off at a predetermined duty ratio.

In the example shown in FIG. 3, the controller CP
Of the program executed by the U, the process of realizing the duty ratio calculating means 13b, and the switching elements 10x-1
The step of realizing the modulation means 13e for intermittently driving the drive signal given to 0z at the duty ratio calculated by the duty ratio calculation means makes the drive current a PWM waveform current having the duty ratio calculated for the throttle signal. Thus, the PWM control means for controlling the switch circuit 10 is configured.

In the brushless DC motor, the maximum generated torque and the maximum rotation speed change depending on the control advance angle γ. Generally, the magnitude of the control advance angle is set according to the use of the electric motor, the required torque characteristics, the required maximum rotational speed, and the like. In the case of a brushless DC motor that drives an electric vehicle, when the rotation speed of the motor is equal to or less than a set value, the control advance angle γ is changed to the normal control advance angle γo.
The control advance angle γ is advanced from the regular control advance angle γo with the increase in the rotation speed in a range where the rotation speed of the motor exceeds the set advance start rotation speed, so that the rotation speed of the motor is The control advance angle γ is often controlled so that the advance amount of the control advance angle is fixed at the set maximum value in a range where the rotation speed is equal to or higher than the set advance end rotation speed.

When the control advance angle γ is controlled, the switching angle for switching the phase through which the drive current flows is determined by the control advance angle calculated for the throttle signal with respect to the reference switching angle determined by the output of the position detector. Control lead angle control means for controlling the shift is provided in the controller 13.

The control lead angle control means includes a step of realizing the control lead angle calculation means 13c in a series of steps of a program executed by the CPU of the controller 13,
A step of determining the timing for switching the phase in which the drive current flows is determined from the control advance angle calculated by the control advance angle calculation means 13c and the reference switching angle determined by the excitation phase determination means 13d.

How to set the normal control advance angle γo is arbitrary, but generally, in order to increase the torque at the start of the electric vehicle, the control advance angle at which the maximum torque is obtained is set to the normal control advance angle γo. The lead angle is γo.

When the control is performed such that the control advance angle γ is advanced beyond the normal control advance angle γo in a region where the rotational speed N exceeds the set value, the amount of displacement of the speed adjusting member to the speed increasing side on an uphill or the like is reduced. When operating at the maximum state (full throttle state), the advance amount of the control advance angle γ is maintained at the maximum value, and the drive current of the electric motor exceeds the rated value . If such a state continues for a long time, the temperature of the armature coil and the switch element of the switch circuit rises and exceeds an allowable value, which may be damaged.

Therefore, in the present invention, an armature coil temperature detector for detecting the temperatures of the armature coils Lu to Lw (in the illustrated example, constituted by the temperature sensitive resistance elements Rtu to Rtw), and a switch circuit. A temperature detector for the switch circuit (constituted by a temperature-sensitive resistance element Rts) for detecting the temperature of 10 and a temperature detected by the temperature detector for the armature coil and detected by the temperature detector for the switch circuit. When one of the set temperatures exceeds a set value (abnormal temperature rise), the value of the throttle signal is corrected to a value smaller than the actual value, and the throttle signal given to the controller when the temperature rises abnormally By making the opening degree information apparently small, the drive current flowing through the armature coil is limited, and the temperature rise of the armature coil and the switch circuit is suppressed.

In order to perform the above control, in the present invention, the temperature detected from the armature coil temperature detectors (Rtu to Rtw) is lower than the set value set for the armature coil, and When the temperature detected by the switch circuit temperature detector Rts is lower than the set value set for the switch circuit, the value Vth of the throttle signal obtained from the throttle sensor is left as it is, and the armature coil temperature detector When the detected temperature is higher than the set value set for the armature coil, or when the temperature detected by the switch circuit temperature detector is higher than the set value set for the switch circuit In addition, the throttle signal value is corrected according to the detected temperature so that the value of the throttle signal is corrected to a smaller value as the detected temperature is higher. And a duty ratio calculating means 13b and a control lead angle of the PWM control means so as to calculate a duty ratio and a control advance angle with respect to the value of the throttle signal corrected by the throttle signal correcting means 13f. The control lead angle calculating means 13c of the control means is constituted.

The throttle signal correcting means 13f outputs, for example, Vth the digitally converted value of the throttle signal output from the throttle sensor, Vmin the digitally converted value of the throttle signal when starting the DC motor, and d the correction rate.
(<100) [%], the correction value Vth ′ of the throttle signal is calculated by the following equation.

Vth ′ = (Vth−Vmin) × d / 100 + Vmin (1) The correction rate d is changed with respect to the detected temperature, for example, as shown in FIG. That is, the correction rate d is set to 100 [%] in a range where the detected temperature is less than the set value (temperature increase suppression control start temperature), and the correction rate d is set in a range where the detected temperature is equal to or higher than the set value. The temperature is decreased as the temperature rises, and becomes zero when the detected temperature reaches the limit value tmax.

The calculation of the correction rate d is performed using a correction rate calculation map that gives a relationship as shown in FIG. 5 between the detected temperature and the correction rate d. This correction rate calculation map is provided for each of the armature coil and the switch circuit, and the temperature rise suppression control start temperature is different between the case of the armature coil and the case of the switch circuit. When it is detected that the temperature of the armature coil has become equal to or higher than a set value (temperature increase suppression control start temperature) set for the armature coil, a correction rate calculation map provided for the armature coil is provided. And the correction value dth of the throttle signal is calculated according to the equation (1), and the temperature of the switch circuit is set to the set value (temperature rise suppression control start temperature) set for the switch circuit. When this is detected, the correction rate d is calculated using the correction rate calculation map provided for the switch circuit, and the correction value Vth 'of the throttle signal is calculated by equation (1).

FIG. 4 shows a throttle signal (digitally converted value).
Shows an example of the relationship between the corrected value Vth 'of FIG. 7 and the throttle signal (digitally converted value) Vth before the correction, wherein a, b, c and d in FIG.
t2 ° C, t3 ° C and t4 ° C (t1 <t2 <t3 <t4)
Is shown.

As described above, the value of the throttle signal is corrected with respect to the temperature detected by the temperature detector, the duty ratio is calculated in the PWM control using the corrected throttle signal, and the control advance in the control advance angle control is performed. By calculating the angle, when the temperature rises, the detected throttle opening can be reduced apparently to suppress the magnitude of the drive current, so that the temperature rise of the armature coil and the switch circuit is suppressed. can do.

Since the correction calculation of the throttle signal is a very simple calculation, the temperature suppression control can be easily performed without performing a complicated map calculation.

In the above example, the temperature detector is constituted by a temperature-sensitive resistance element. However, the temperature detector can be constituted by using another temperature sensor such as a thermocouple.

In the above example, the drive current of the PWM waveform is obtained by turning on and off the lower switch element of the switch circuit. However, the drive current of the PWM waveform is obtained by turning on and off the upper switch element of the switch circuit. May be obtained, and a drive current having a PWM waveform may be obtained by turning on and off both the upper switching element and the lower switching element.

In the above example, the Hall IC constituting the position detector is disposed at a position advanced by 90 degrees in the armature angle with respect to the center of the tooth around which the armature coil of each phase is wound. It is sufficient that the detector detects the rotational angle position of the rotor with respect to the stator, and the arrangement position is not limited to the above example.

In the above example, the 180-degree switching control is performed. However, the driving method of the brushless DC motor is not limited to the above example, and for example, the teeth around which the armature coils of each phase are wound. The present invention is also applicable to the case where the motor is rotated by performing "120-degree switching control" in which a drive current is applied to the armature coil of each phase in a section of 60 degrees (electrical angle) before and after the position where the magnetic flux flowing through the section passes through the zero point. Can be applied.

Although the Hall IC is used as the position detector in the above example, a position detector such as a photo encoder may be used instead of the Hall IC.

In the above example, the temperature-sensitive resistance elements Rtu to Rtw (temperature sensors) are thermally coupled to each of the three-phase armature coils, and these temperature-sensitive resistance elements are connected in parallel. Configured the temperature detector for the armature coil,
When the temperature detector for the armature coil is configured in this manner, the average value of the temperatures of the three-phase armature coils can be detected from the parallel combined resistance value. Even when the temperature of the armature coil of a specific phase rises abnormally, a temperature detection signal reflecting the abnormal rise in temperature can be obtained, so that the armature coil can be properly protected.

The temperature-sensitive resistance elements respectively attached to the three-phase armature coils are connected in parallel as described above, and the temperature corresponding to the average value of the temperatures of the three-phase armature coils is calculated from the parallel combined resistance value. Is detected, only one input port of the CPU of the controller 13 to be allocated for reading the temperature of the armature coil is required, so that the cost can be reduced by using a CPU having a small number of ports.

However, the present invention is not limited to the case where the temperature-sensitive resistance elements respectively attached to the three-phase armature coils are connected in parallel as described above. Temperature detection signals obtained from the temperature-sensitive resistance elements may be individually input to the CPU of the controller 13. In such a configuration, the temperatures of the three-phase armature coils are individually monitored by the CPU, and when the temperature of any one of the armature coils exceeds a set value, the value of the throttle signal is reduced. The correction may be performed.

Further, the present invention is not limited to the case where the temperature sensors are attached to the armature coils of all the phases. There is no possibility that the electric motor is locked, and the temperature of the armature coils of the specific phase is abnormal. If there is no possibility of rising, the temperature detector may be configured to detect only the temperature of any one of the armature coils.

The electric vehicle to which the present invention is applied may have a structure in which the output of the electric motor is directly transmitted to the drive wheels of the vehicle.
The output of the electric motor may be transmitted to the drive wheels via a reduction gear.

In the above example, a three-phase brushless motor is taken as an example, but the number of armature coils in the present invention is arbitrary.

[0087]

As described above, according to the present invention, the value of the duty ratio in the PWM control is corrected by correcting the value of the throttle signal with respect to the temperature detected by the temperature detector and using the corrected throttle signal. Calculation and calculation of the control lead angle in the control lead angle control are performed, so that the duty ratio and the control lead angle are controlled with respect to the detected temperature only by performing a very simple calculation, and the temperature suppression control is performed. Can be easily performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing an overall configuration of the embodiment of FIG. 1 including a configuration of various function realizing means realized by causing a microcomputer to execute a predetermined program by a controller;

FIG. 3 is a waveform diagram showing a waveform of a position detection signal in the brushless DC motor of FIG. 1, and an ON / OFF operation waveform of each switch element of a switch circuit.

FIG. 4 is a diagram showing a relationship between a corrected value of a throttle signal and a throttle signal before correction.

FIG. 5 is a diagram illustrating an example of a relationship between a correction rate and a temperature used for calculating a correction value of a throttle signal.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Brushless DC motor, 2 ... Rotor, 3 ... Stator, Lu-Lw ... Armature coil, hu-hw ... Position detector, 10 ... Switch circuit, 13 ... Controller, 15 ...
Throttle sensor, Rtu-Rtw, Rts ... temperature-sensitive resistance element.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H115 PA08 PC06 PG04 PI16 PU01 PU21 PV09 PV23 QN02 QN04 RB22 SE03 TO05 TO21 TU12 5H560 AA08 BB04 BB07 BB12 DA02 DC05 DC13 EB01 EB05 EC10 GG01 GG04 JJ06 XA02 XA02 XA02 XA02 XA02

Claims (5)

[Claims] A brushless DC motor for driving an electric vehicle, comprising: a rotor having a magnet field and a stator having a multi-phase armature coil; a position detector for detecting a rotation angle position of the rotor with respect to the stator; A switch circuit provided between the DC power supply and the armature coil to switch a phase in which a drive current flows from the power supply to the armature coil, and a speed adjusting member operated when adjusting the rotation speed of the motor. A throttle sensor that detects a displacement amount of the speed adjusting member as a throttle opening and outputs a throttle signal of a magnitude corresponding to the throttle opening, and an output of the position detector to rotate the rotor. A controller that controls the switch circuit so as to switch a phase in which the drive current flows, wherein the controller controls the drive current PWM control means for controlling the switch circuit so as to obtain a PWM waveform current having a duty ratio calculated for the throttle signal, and a switching angle of a phase in which the drive current flows is calculated for the throttle signal. A drive device for a brushless DC motor for driving an electric vehicle, comprising: a control lead angle control means for controlling the shift by a control lead angle with respect to a reference switching angle determined by the output of the position detector. A temperature detector for detecting the temperature of a monitoring-required component selected from the components that generate heat by flowing, and a throttle signal output by the throttle sensor when the temperature detected by the temperature detector is lower than a set value. When the detected temperature is equal to or higher than the set value, the higher the temperature, the higher the temperature. Throttle signal correction means for correcting the value of the throttle signal according to the detected temperature so as to correct the value of the throttle signal obtained from the throttle sensor to a small value; and the PWM control means and the control advance angle. The control means is configured to calculate the duty ratio and the control advance angle with respect to the value of the throttle signal corrected by the throttle signal correction means, and the brushless DC motor for driving an electric vehicle is driven. apparatus. 2. A brushless DC motor for driving an electric vehicle, comprising: a rotor having a magnet field and a stator having a multi-phase armature coil; a position detector for detecting a rotation angle position of the rotor with respect to the stator; A switch circuit provided between the DC power supply and the armature coil to switch a phase in which a drive current flows from the power supply to the armature coil, and a speed adjusting member operated when adjusting the rotation speed of the motor. A throttle sensor that detects a displacement amount of the speed adjusting member as a throttle opening and outputs a throttle signal of a magnitude corresponding to the throttle opening, and an output of the position detector to rotate the rotor. A controller that controls the switch circuit so as to switch a phase in which the drive current flows, wherein the controller controls the drive current PWM control means for controlling the switch circuit so as to obtain a PWM waveform current having a duty ratio calculated for the throttle signal, and a switching angle of a phase in which the drive current flows is calculated for the throttle signal. A drive device for a brushless DC motor for driving an electric vehicle, comprising: a control lead angle control means for controlling the shift by a control lead angle with respect to a reference switching angle determined by the output of the position detector. A plurality of temperature detectors each detecting a temperature of a plurality of monitoring required components selected from components that generate heat due to the flow of, a temperature of the plurality of monitoring required components detected by the plurality of temperature detectors. When all of them are lower than the set values set for each of the plurality of monitored parts, the values obtained from the throttle sensor are obtained. When it is detected that the temperature of any of the monitored components has become equal to or higher than the set value set for the monitored component, the higher the detected temperature is, the more the throttle signal becomes. Throttle signal correcting means for correcting the value of the throttle signal in accordance with the detected temperature so as to correct the value of the signal to a small value. The PWM control means and the control lead angle control means each comprise the throttle A driving device for a brushless DC motor for driving an electric vehicle, wherein the duty ratio and the control advance angle are calculated with respect to the value of the throttle signal corrected by the signal correcting means. 3. The drive device for a brushless DC motor for driving an electric vehicle according to claim 2, wherein the plurality of monitored parts are switch elements constituting the armature coil and the switch circuit. 4. A brushless DC motor for driving an electric vehicle, comprising: a rotor having a magnet field and a stator having a multi-phase armature coil; a position detector for detecting a rotation angle position of the rotor with respect to the stator; A switch circuit provided between the DC power supply and the armature coil to switch a phase in which a drive current flows from the power supply to the armature coil, and a speed adjusting member operated when adjusting the rotation speed of the motor. A throttle sensor that detects a displacement amount of the speed adjusting member as a throttle opening and outputs a throttle signal of a magnitude corresponding to the throttle opening, and an output of the position detector to rotate the rotor. A controller that controls the switch circuit so as to switch a phase in which the drive current flows, wherein the controller controls the drive current PWM control means for controlling the switch circuit so as to obtain a PWM waveform current having a duty ratio calculated for the throttle signal, and a switching angle of a phase in which the drive current flows is calculated for the throttle signal. A driving device for a brushless DC motor for driving an electric vehicle, comprising: a control advance angle control means for performing control so as to shift by a control advance angle with respect to a reference switching angle determined by an output of the position detector. An armature coil temperature detector provided to detect the temperature of the armature coil, a switch circuit temperature detector for detecting the temperature of the switch circuit, and a temperature detected by the armature coil temperature detector. Temperature is lower than a set value set for the armature coil, and is detected by the switch circuit temperature detector. When the temperature is lower than the set value set for the switch circuit, the value of the throttle signal obtained from the throttle sensor is kept as it is, and the temperature detected by the armature coil temperature detector is applied to the armature coil. When the temperature detected by the switch circuit temperature detector is equal to or higher than the set value set for the switch circuit, or when the temperature detected by the switch circuit temperature detector is equal to or higher than the set value set for the switch circuit. Throttle signal correcting means for correcting the value of the throttle signal in accordance with the detected temperature so as to correct the value of the throttle signal to a smaller value as the value is higher; the PWM control means and the control lead angle control Means for controlling the duty ratio and the control advance angle with respect to the value of the throttle signal corrected by the throttle signal correcting means, respectively. Electric vehicle driving brushless DC motor of the driving apparatus characterized by being configured to calculate. 5. The throttle signal correcting means includes: a throttle signal value Vth output by the throttle sensor;
Using the value Vmin of the throttle signal at the start of starting the DC motor and a correction rate d (<100) [%], an arithmetic expression Vth ′ = (Vth−Vmin) × d / 100 + V
A correction value Vth 'of the throttle signal is calculated by min. The correction rate d is set to 100 [%] in a range where the detected temperature indicates a value less than the set value. In a range in which the corrected temperature is equal to or more than the set value, the correction rate d is calculated using a correction rate calculation map that defines a relationship between the temperature and the correction rate so as to decrease as the temperature increases. The driving device for a brushless DC motor for driving an electric vehicle according to any one of claims 1 to 4, wherein: