JP2002051583A - Motor driver, and motor driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the abnormality of an inverter certainly and quickly. SOLUTION: This motor driver has a power source, a motor 31, an inverter 40 which converts the current supplied from the above power source into phase current, accompanying the switching of a switching element, and supplies it to the above motor 31, an inverter temperature detection means which detects the temperature of that inverter 40 as the actual temperature, a state value computing means 91 which computes the state value to show the state of the inverter 40, and a limited torque computing means 92 which computes the limited torque, based on one hand of the above actual temperature and the state value. Since the limited torque is computed based on one hand of the actual temperature and the state value, the temperature of each switching element goes high suddenly in case that the requested torque is large, but this motor driver can detect the abnormality of the inverter 40 quickly based on the state value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving device and a motor driving method.

[0002]

2. Description of the Related Art Conventionally, in an electric vehicle, a motor comprising a stator having U-phase, V-phase and W-phase stator coils, and a rotor rotatably disposed inside the stator and having a magnetic pole pair. The motor is driven by supplying U-phase, V-phase and W-phase currents to the stator coil by a motor driving device.

When a vehicle control circuit for controlling the entire electric vehicle calculates a torque command value, calculates a current command value based on the torque command value, and sends the current command value to a motor control unit.
The motor control unit generates U-phase, V-phase, and W-phase pulse width modulation signals having pulse widths corresponding to the current command values, and sends the pulse width modulation signals to a drive circuit.

[0004] The drive circuit generates a switching signal corresponding to the pulse width modulation signal, and sends the switching signal to an inverter. The inverter has six transistors as switching elements. The inverter turns on the transistors only while the switching signal is on to generate current of each phase, and supplies the current of each phase to the stator coil.

[0005] In this way, by operating the motor control unit, the motor is driven, a motor torque is generated, and the motor torque can be transmitted to the drive wheels to drive the electric vehicle.

[0006] Since the stator coils of the motor are star-connected, when the values of the two phases of the current of each phase, for example, the currents of the U-phase and the V-phase are determined, the remaining one phase, For example, the value of the W-phase current is also determined. Therefore, in order to control the current of each phase, the U-phase and V-phase currents are detected by the current sensors.
Feedback control is performed on a dq-axis model in which the d-axis is taken in the direction of the magnetic pole pair of the rotor and the q-axis is taken in a direction perpendicular to the d-axis.

Therefore, in the motor control unit,
The U-phase and V-phase currents undergo three-phase / two-phase conversion to become d-axis current and q-axis current. Then, a d-axis current deviation between the d-axis current and the d-axis current command value and a q-axis current deviation between the q-axis current and the q-axis current command value are calculated, respectively, and the d-axis current deviation and the q-axis current deviation are calculated. A d-axis voltage command value and a q-axis voltage command value are generated so as to be zero (0).
Subsequently, the d-axis voltage command value and the q-axis voltage command value are two-phase /
The three-phase conversion is performed to obtain U-phase, V-phase, and W-phase voltage command values, and the U-phase, V-phase, and W-phase
A phase pulse width modulated signal is generated.

When the transistor is selectively switched, that is, turned on and off, heat is generated. Therefore, the transistor is cooled by a heat sink. However, when the transistor cannot be cooled sufficiently, Not only does the characteristics of the transistor deteriorate, but also the durability of the transistor decreases. Therefore, a temperature sensor is provided at a predetermined position in the inverter, the temperature of the inverter is detected by the temperature sensor, and the detected temperature, that is, the actual temperature is a threshold.
When the value exceeds the threshold value, an abnormality of the inverter is detected, and the limit value of the torque command value, that is, the limit torque is reduced to lower the temperature of the transistor.

[0009]

However, in the conventional motor driving device, the temperature sensor is provided at a predetermined position in the inverter and only detects the temperature of the inverter locally. Abnormality cannot be reliably detected. For example, when the drive circuit generates a switching signal and sends the switching signal to the inverter, but the rotor does not rotate for some reason, that is, a stall state occurs, only a predetermined transistor is turned on. The temperature of the inverter locally increases, but the actual temperature does not increase if a temperature sensor is disposed at a position distant from the predetermined transistor.
Therefore, it is not possible to reliably detect the abnormality of the inverter, and it is not possible to reduce the limit torque.
In some cases, the temperature of the transistor cannot be lowered.

The motor torque required for running the electric vehicle, such as when starting, climbing up a slope, or suddenly accelerating, etc.
That is, when the required torque is large, the temperature of each transistor rises sharply, and the temperature of the inverter also rises sharply. However, the temperature sensor cannot sufficiently follow a rise in temperature, and has low responsiveness. Therefore,
Since it is not possible to quickly detect the abnormality of the inverter, it is delayed to reduce the torque limit and to delay the temperature of the transistor.

An object of the present invention is to solve the problems of the conventional motor driving device and to provide a motor driving device and a motor driving method capable of reliably and quickly detecting an abnormality of an inverter. And

[0012]

For this purpose, in the motor driving apparatus according to the present invention, the current supplied from the power supply is converted into a phase current by switching the power supply, the motor, and the switching element. An inverter to be supplied to the motor; inverter temperature detection means for detecting the temperature of the inverter as an actual temperature; state value calculation processing means for calculating a state value representing the state of the inverter; and one of the actual temperature and the state value And a limit torque calculation processing means for calculating the limit torque based on

In another motor driving device of the present invention,
Further, the state value is a continuous stall time indicating that the inverter is in a stall state. The state value calculation processing means is a continuous stall time calculation processing means.

In still another motor drive device of the present invention, the state value is an estimated temperature representing the entire temperature of the inverter. The state value calculation processing means is an estimated temperature calculation processing means.

In still another motor driving device of the present invention, the state value is a continuous stall time indicating that the inverter is in a stall state, and an estimated temperature indicating the entire temperature of the inverter. The state value calculation processing means is a continuous stall time calculation processing means and an estimated temperature calculation processing means.

In still another motor driving device according to the present invention, the estimated temperature calculation processing means calculates a temperature correction value corresponding to a state of the inverter, and calculates an actual temperature detected at a predetermined timing. And calculating the estimated temperature based on the temperature correction value.

According to the motor driving method of the present invention, the current supplied from the power supply is converted into a phase current and supplied to the motor in accordance with the switching of the switching element constituting the inverter, and the temperature of the inverter is detected as the actual temperature. And
A state value representing a state of the inverter is calculated, and a limit torque is calculated based on one of the actual temperature and the state value.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a functional block diagram of a motor driving device according to an embodiment of the present invention.

In FIG. 1, reference numeral 14 denotes a battery as a power supply, 31 denotes a motor, and 40 denotes a motor 31 which converts a current supplied from the power supply 14 into a phase current with the switching of a transistor (not shown) as a switching element. , And 22 is the inverter 4
A temperature sensor as inverter temperature detection means for detecting a temperature of 0 as an actual temperature; 91, a state value calculation processing means for calculating a state value representing the state of the inverter 40; 92, one of the actual temperature and the state value Is a limit torque calculation processing means that calculates the limit torque based on

FIG. 2 is a conceptual diagram of a motor drive device according to an embodiment of the present invention, and FIG. 3 is a block diagram of a motor control unit according to the embodiment of the present invention.

In the drawing, reference numeral 10 denotes a motor driving device;
Is a vehicle control circuit for controlling the entire electric vehicle, 31 is a motor, and 45 is a motor control unit for controlling the motor 31. A DC brushless motor is used as the motor 31. The motor 31 includes a rotor (not shown) rotatably disposed, and a stator disposed radially outward from the rotor. The stator includes a stator core and a U-phase, V-phase wound around the stator core. Phase and W
Phase stator coils 11 to 13 are provided.

In order to drive the electric vehicle by driving the motor 31, a DC current from the battery 14 as a power source is supplied to the inverter 4 via the main relay 15.
0, and is converted by the inverter 40 into U-phase, V-phase and W-phase currents I _U , I _V , I _W as phase currents, and the currents I _U , I _V , I _W of each phase are respectively It is supplied to the stator coils 11 to 13.

For this purpose, the inverter 40 includes transistors Tr1 to Tr as six switching elements.
6 by turning on / off each of the transistors Tr1 to Tr6, so that the currents I _U , I _V , I _W
Can be generated.

Further, a drum (not shown) is mounted on the shaft of the rotor, and a small magnet is mounted on the drum. The magnet is opposed to the drum, and a magnetoresistive element as a simple magnetic pole position sensor, for example, a Hall element 43 is provided. The Hall element 43 detects the position of the small magnet in accordance with the rotation of the rotor, and outputs a sensor output at each predetermined angle (in the present embodiment, 60 °). position detection signal P _U of, P _V, to generate P _W, and sends to the magnetic pole position detecting circuit 44 as a magnetic pole position detection means. The magnetic pole position detection circuit 44 receives the position detection signals P _U , P _V , and P _W to detect the magnetic pole position θ, generates a detection pulse, and outputs the magnetic pole position θ and the detection pulse to a motor control unit. Send to 45. Further, a capacitor 20 is provided between the main relay 15 and the inverter 40. The capacitor 20 is charged when an ignition key (not shown) is turned on and the main relay 15 is turned on, and is applied to the inverter 40. The applied voltage. Then, a positive polarity terminal and a negative polarity terminal of the capacitor 20 are connected to the DC voltage detection circuit 16, and the DC voltage detection circuit 16
Voltage across the terminals, i.e., detects a DC voltage V _C, the vehicle control circuit the DC voltage V _C 17 and a motor control unit 45
Send to Further, upon receiving the detection pulses from the magnetic pole position detection circuit 44, the motor control unit 45 calculates the rotation speed of the motor 31, that is, the motor rotation speed Nm, based on the timing of each detection pulse. Send to Then, the vehicle control circuit 17 determines the motor rotation speed N
The vehicle speed V corresponding to m is detected.

The stator coils 11 to 13
Are star connected, so two of each phase,
For example, when the values of the U-phase and V-phase currents are determined, the remaining
One phase, for example, the value of the current of the W phase is also determined. Accordingly
And the current I of each phase_U, I_V, I _WU to control
Phase and V phase current I_U, I_VTo detect the stator
Current sensors 33, 34 are connected to the lead wires of the coils 11, 12, respectively.
Disposed as the sensor output of the current sensors 33 and 34
Detection signal SG_U, SG_VIs sent to the motor control unit 45.
You.

Reference numeral 18 denotes an accelerator sensor provided on an accelerator pedal (not shown). When the driver depresses the accelerator pedal, the accelerator sensor 18 detects the accelerator pedal depression amount, that is, the accelerator opening α. To the vehicle control circuit 17.

A command value generator (not shown) of the vehicle control circuit 17 generates a torque command value Tm based on the accelerator opening α, vehicle speed V, and the like sent from the accelerator sensor 18, and generates the torque command value Tm. It is sent to the motor control unit 45.
The motor control unit 45 generates a d-axis current command value _ids and a q-axis current command value _iqs as a current command value Im based on the torque command value Tm. And the motor control unit 4
5 calculates the pulse width based on the magnetic pole position θ, the detection signals SG _U , SG _V , the d-axis current command value _ids and the q-axis current command value _iqs , and calculates the U-phase and V-phase having the pulse width. and W-phase pulse width modulated signal S _U, S _V, to generate S _W, sends a pulse width modulated signal S _U of the respective phase, S _V, the S _W to the drive circuit 51. The drive circuit 51, the phase of the pulse width modulated signal S _U, S _V, by receiving S _W, the transistor T
A switching signal as six drive signals for driving r1 to Tr6 is generated, and the switching signal is sent to the inverter 40. The inverter 40 controls the transistor Tr1 only while the switching signal is on.
Current I _U turn on the ~Tr6, I _V, to generate I _W, and supplies respective currents I _U, I _V, the I _W to each stator coil 11 to 13. Thus, the electric vehicle can be driven by driving the motor 31.
In the present embodiment, each drive wheel has a motor 3
1 are provided, and six transistors Tr1 to Tr6 are provided corresponding to each motor 31.

The motor control unit 45 performs feedback control by vector control on a dq-axis model in which the d-axis is taken in the direction of the rotor magnetic pole pair and the q-axis is taken in the direction perpendicular to the d-axis. Control is performed.

For this purpose, the detection signals SG _U and SG _V sent from the current sensors 33 and 34 and the magnetic pole position θ are sent to the UV-dq converter 61 in the motor control section 45. The UV-dq converter 61, the detection signal SG _U, SG _V and performs three-phase / two-phase conversion on the basis of the magnetic pole position theta, detection signal SG _U, SG _V and the magnetic pole position theta d-axis current i Convert to _d and q axis currents _iq .

[0031] Then, the d-axis current i _d is fed to a subtractor 62, a d-axis current deviation .DELTA.i _d between the d-axis current i _d and the d-axis current command value i _ds is calculated in subtractor 62, the d-axis current deviation .DELTA.i _d is sent to a d-axis voltage command value generating unit 64. On the other hand, q-axis current i _q is fed to the subtracter 63, the q-axis current i _q and q-axis current command value i _qs in subtractor 63
Q-axis current deviation .DELTA.i _q is calculated with, the q-axis current deviation Δ
_iq is sent to the q-axis voltage command value generator 65. Note that d
Axis voltage command value generating section 64 and q-axis voltage command value generating section 65
The voltage command value generating means is constituted by the above.

The d-axis voltage command value generating section 64 and the q-axis voltage command value generating section 65 include a parameter calculating section 71.
Q-axis inductance sent from L _q and d-axis inductance L _d, and on the basis of the d-axis current deviation .DELTA.i _d and q-axis current deviation .DELTA.i _q, d-axis current deviation .DELTA.i _d and q-axis current deviation .DELTA.i _q is zero To generate a d-axis voltage command value V _d ^* and a q-axis voltage command value V _q ^* as inverter outputs on two axes, respectively, and the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* is converted to dq-UV converter 6
Send to 7.

Subsequently, the dq-UV converter 67
d-axis voltage command value V_d ^*, Q-axis voltage command value V_q ^*And magnetic pole
Performs two-phase / three-phase conversion based on position θ, and outputs d-axis voltage command.
Value V _d ^*And q-axis voltage command value V_q ^*To U-phase, V-phase and W-phase
Phase voltage command value V_U ^*, V_V ^*, V_W ^*To each of the
Phase voltage command value V_U ^*, V_V ^*, V_W ^*Is a PWM generator
Send to 68. The PWM generator 68 provides a voltage reference for each phase.
Remarks V_U ^*, V_V ^*, V_W ^*And the DC voltage V_CBased on
The pulse width modulation signal S of each phase_U, S_V, S _WOccurs
Let it.

Incidentally, the transistors Tr1 to Tr
When the transistor 6 is turned on and off, heat is generated.
Are cooled, but the transistors Tr1 to T
If r6 cannot be sufficiently cooled, not only the characteristics of the transistors Tr1 to Tr6 will deteriorate, but also the durability of the transistors Tr1 to Tr6 will decrease. Therefore, a temperature sensor 22 as an inverter temperature detecting means is provided at a predetermined position in the inverter 40, and when the actual temperature of the inverter 40 detected by the temperature sensor 22 exceeds a threshold, abnormality of the inverter 40 is determined. It is conceivable to lower the temperature of the inverter 40 by detecting and reducing the limit torque.

However, the temperature sensor 22 is disposed at a predetermined position in the inverter 40,
Since only the temperature of 0 is locally detected, the abnormality of the inverter 40 cannot be reliably detected when the temperature of the inverter 40 locally increases. That is, for example, if the drive circuit 51 generates a switching signal and sends the switching signal to the inverter 40, but a stall state occurs for some reason, only a predetermined transistor remains ON. Although the temperature of the inverter 40 locally increases, the actual temperature does not increase if the temperature sensor 22 is disposed at a position distant from the predetermined transistor. In this case, the abnormality of the inverter 40 cannot be detected, and the limit torque cannot be reduced.

When the required torque is large, such as when starting, climbing a hill, or suddenly accelerating, each transistor Tr1
The temperature of Tr6 rises sharply, and the temperature of the inverter 40 also rises sharply. However, the temperature sensor 22
Cannot respond sufficiently to a rise in temperature and has low responsiveness. Therefore, it is not possible to quickly detect the abnormality of the inverter 40, so that the reduction of the limit torque is delayed and the reduction of the temperature of the inverter 40 is delayed.

Therefore, in this embodiment, in order to detect the abnormality of the inverter 40 reliably and promptly, the abnormality of the inverter 40 is detected by a plurality of abnormality determination methods, and the limit torque is reduced. By doing so, the temperature of the transistors Tr1 to Tr6 is reduced.

Next, the operation of the motor driving device 10 will be described.

FIG. 4 is a main flowchart showing the operation of the motor driving device according to the embodiment of the present invention, FIG. 5 is a diagram showing a subroutine of an estimated temperature calculating process in the embodiment of the present invention, and FIG. FIG. 7 is a diagram showing a subroutine of an estimated temperature coefficient calculating process in the embodiment, FIG. 7 is a diagram showing a subroutine of a heat radiation amount calculating process in the embodiment of the present invention, and FIG. 8 is a subroutine of an offset temperature calculating process in the embodiment of the present invention. FIG. 9 is a first diagram illustrating a region of a motor rotation speed and a required torque according to the embodiment of the present invention. FIG. 10 is a diagram illustrating a subroutine of a stall determination process according to the embodiment of the present invention. 1
1 is a diagram showing a subroutine of a limit torque calculation process according to the embodiment of the present invention, FIG. 12 is a time chart showing an operation of a stall determination process according to the embodiment of the present invention,
FIG. 13 is a diagram showing a relationship between the second torque limit value and the estimated temperature in the embodiment of the present invention, and FIG. 14 is a diagram showing a relationship between the third torque limit value and the actual temperature in the embodiment of the present invention. FIG. In FIG. 9, the horizontal axis represents the motor rotation speed Nm, the vertical axis represents the required torque Tn, the horizontal axis represents the estimated temperature te, the vertical axis represents the second torque limit value ρ2, and FIG. , The horizontal axis represents the actual temperature, and the vertical axis represents the third temperature.
Is adopted.

First, the required torque calculation processing means (not shown) of the vehicle control circuit 17 (FIG. 2) performs a required torque calculation process, and calculates the required torque based on the accelerator opening α, the vehicle speed V, and the like sent from the accelerator sensor 18. And sends the required torque to the motor control unit 45 as a torque command value Tm. Here, the required torque is a value obtained by converting the output value of the motor torque into a torque command value.

Subsequently, the estimated temperature calculation processing means 93 of the motor control unit 45 performs an estimated temperature calculation process, and estimates by calculating the entire temperature of the inverter 40 as the estimated temperature te. The estimated temperature te constitutes a state value representing the state of the inverter 40, and the estimated temperature calculation processing means 93 makes the state value calculation processing means 91
(FIG. 1) is configured. Then, the motor control unit 45
The stall determination processing means 94 performs a stall determination process to determine whether a stall state has occurred. Subsequently, the limiting torque calculation processing means 92 of the motor control unit 45
Performs a limit torque calculation process, and calculates a limit torque based on the estimated temperature te calculated by the estimated temperature calculation process and the determination result by the stall determination process.

Then, the target torque calculation processing means 95 of the motor control unit 45 performs a target torque calculation process, determines whether the torque command value Tm is larger than the limit torque, and determines whether the torque command value Tm is smaller than the limit torque. When it is larger, the limit torque is calculated as the target torque, and when the torque command value Tm is equal to or less than the limit torque, the torque command value Tm is calculated as the target torque. Subsequently, the current command value calculation processing means 96 of the motor control unit 45 performs a current command value calculation process, and calculates a d-axis current command value _ids and a q-axis current command value _iqs based on the target torque and the like. I do.

Next, the flowchart will be described. Step S1 A torque command value Tm is calculated. Step S2: Perform an estimated temperature calculation process. Step S3 Stall determination processing is performed. Step S4: Perform a limit torque calculation process. Step S5: It is determined whether the torque command value Tm is larger than the limit torque. When the torque command value Tm is larger than the limit torque, the process proceeds to step S7, and when the torque command value Tm is equal to or less than the limit torque, the process proceeds to step S6. Step S6: Set the torque command value Tm to the target torque. Step S7: Set the limit torque to the target torque. Step S8: Calculate the d-axis current command value _ids and the q-axis current command value _iqs as the current command value Im, and end the process.

Next, the subroutine of the estimated temperature calculating process in step S2 of FIG. 4 will be described.

In calculating the estimated temperature te, a predetermined timing, in this embodiment, the time when the estimation of the estimated temperature te is started, that is, the estimation start time is specified, and is detected by the temperature sensor 22 at the estimation start time. The actual temperature, that is, the estimated start temperature tm _ST is recorded in a memory (not shown) in the motor control unit 45. The estimated temperature te corresponds to the state of the inverter 40, and is calculated from the estimated start temperature tm _ST , the offset temperature to due to heat potentially held by the inverter 40 at the estimated start time, and Is calculated based on the integrated value Ad representing the heat balance of the inverter 40 up to and represented by the following equation (1). In this case, the first temperature correction value is calculated based on the offset value to and the integrated value A.
d constitutes a second temperature correction value.

Te = tm _ST + to + Ad (1) Then, the integrated value Ad is determined by the transistors Tr1 to Tr
6 is calculated based on the amount of heat Q associated with turning on and off of the inverter 6 and the amount of heat radiation R from the inverter 40, and calculates a value obtained by subtracting the amount of heat radiation R from the amount of heat Q as in the following equation (2). It is represented by the value integrated from time to the present.

Ad = ∫ (Q−R) dt (2) Therefore, the estimated temperature te is represented by the following equation (3).

Te = tm _ST + to + ∫ (Q−R) dt (3) Then, assuming that the estimated temperature coefficient is K and the required torque is Tn, the calorific value Q is Q = K · Tn ² Therefore, the estimated temperature te is expressed by the following equation (4).

Te = tm _ST + to + ∫ (K · Tn ² −R) dt (4) Note that, as described later, the heat release amount R and the estimated temperature coefficient K are calculated in each area AR1 shown in FIG. .. Are set in advance for each AR6.

The estimated temperature calculation processing means 93
Reads the torque command value Tm and reads the estimated start temperature tm _ST from the memory. Subsequently, an estimated temperature coefficient calculation processing unit (not shown) of the estimated temperature calculation processing unit 93 calculates an estimated temperature coefficient K by performing an estimated temperature coefficient calculation process, and a heat radiation amount (not shown) of the estimated temperature calculation processing unit 93 is calculated. The calculation processing means calculates the heat radiation amount R by performing the heat radiation amount calculation processing, and the offset temperature calculation processing means (not shown) of the estimated temperature calculation processing means 93 calculates the offset temperature to by performing the offset temperature calculation processing. I do.

When the estimated temperature coefficient K, the heat radiation amount R and the offset temperature to have been calculated in this manner, the estimated temperature calculation processing means 93 performs an estimated temperature calculation process.
Requested torque T represented by the torque command value Tm
Based on n, the estimated start temperature tm _ST , the estimated temperature coefficient K, the heat release amount R, and the offset temperature to, the estimated temperature te is calculated by the above equation (4).

Therefore, the temperature sensor 22 is only provided at a predetermined position in the inverter 40,
Even if the temperature of the inverter 40 is locally high,
An abnormality of the inverter 40 can be detected. That is, in the present embodiment, since the overall temperature of the inverter 40 can be estimated from the estimated temperature te, an abnormality of the inverter 40 can be reliably detected. Therefore, the torque limit can be reduced, and the temperature of inverter 40 can be lowered.

In addition, the offset temperature calculation processing means,
A temperature correction value calculation processing means is constituted by an integration value calculation processing means (not shown) of the estimated temperature calculation processing means 93 for calculating the integration value Ad, and a first temperature correction value calculation processing means is formed by the offset temperature calculation processing means. The second temperature correction value calculation processing means is constituted by the integrated value calculation processing means.

In the present embodiment, the required torque Tn is used to calculate the heat generation amount Q, but the required torque Tn may be replaced by a motor torque generated by the motor 31. . In that case, the value of the estimated temperature coefficient K is changed.

Next, the flowchart will be described. Step S2-1: Read the torque command value Tm. Step S2-2: Read the estimated start temperature tm _ST . Step S2-3: Perform an estimated temperature coefficient calculation process. Step S2-4: A heat radiation amount calculation process is performed. Step S2-5 Offset temperature calculation processing is performed. Step S2-6: Calculate the estimated temperature te and return.

Next, the subroutine of the estimated temperature coefficient calculation process in step S2-3 in FIG. 5 will be described.

In this case, an estimated temperature coefficient K is set in advance for each region to which the motor rotational speed Nm and the required torque Tn belong, and the motor rotational speed Nm and the required torque Tn correspond to the estimated temperature coefficient K in the memory. Is recorded as a table.

First, the estimated temperature coefficient calculation processing means includes:
The motor rotation speed Nm is equal to the first motor rotation speed threshold Nm _TH
1. In the present embodiment, lower than 20 [rpm],
In addition, the absolute value | Tn |
The first required torque threshold value Tn _TH 1 preset in accordance with the rating of
It is determined whether the pixel belongs to the area AR1 shown in FIG. 9 that is larger than [%]. And the motor rotation speed Nm
And the absolute value | Tn | belongs to the area AR1, the estimated temperature coefficient calculation processing means sets the estimated temperature coefficient K to the value k1.

Further, the estimated temperature coefficient calculation processing means includes:
The motor rotation speed Nm and the absolute value | Tn |
1, the motor rotation speed Nm is 20 [rpm].
m] or more, and the absolute value | Tn |
Threshold Tn_TH2 (Tn_TH2> Tn _TH1) In this embodiment
Is 80% or more of the maximum torque.
Torque request threshold Tn_TH3 (Tn_TH3> Tn_TH2), this implementation
In the embodiment, the area smaller than 90% of the maximum torque
It is determined whether it belongs to the area AR2. And the said
Data rotation speed Nm and absolute value | Tn |
The estimated temperature coefficient calculation processing means
The number K is set to a value k2.

Further, when the motor rotation speed Nm and the absolute value | Tn | do not belong to the regions AR1 and AR2, the estimated temperature coefficient calculation processing means determines that the motor rotation speed Nm is not less than 20 [rpm] and that the absolute value | Tn | It is determined whether or not the value | Tn | belongs to the area AR3 in which the value is 90% or more of the maximum torque. When the motor rotation speed Nm and the absolute value | Tn | belong to the area AR3, the estimated temperature coefficient calculation processing unit sets the estimated temperature coefficient K to a value k3.

In addition, the estimated temperature coefficient calculation processing means includes:
The motor rotation speed Nm and the absolute value | Tn |
If it does not belong to 1 to AR3, the estimated temperature coefficient K is set to zero. The values k1 to k3 are set to be k1>k2> k3.

As described above, in the estimated temperature coefficient calculation process, when the motor rotation speed Nm is lower than 20 [rpm], the heat value Q is assumed to be large by setting the value k1 to be large, and the motor rotation speed Nm is reduced. If the absolute value | Tn | is not less than 80 [%] of the maximum torque and less than 90 [%] and the absolute value | Tn | is smaller than 90 [%], the heat value Q is assumed to be small by setting the value k2 small. When the absolute value | Tn | is 90% or more of the maximum torque, the heat value Q is set by setting the value k3 even smaller.
Is further reduced, and in other cases, the heat generation amount Q is assumed to be zero. Note that in FIG. 9, V is the vehicle speed, L _T is a limit torque.

Next, the flowchart will be described. Step S2-3-1: The motor rotation speed Nm is 20 [r
pm] and whether the absolute value | Tn | is greater than 20% of the maximum torque. Motor rotation speed Nm is lower than 20 [rpm] and absolute value | T
If n | is larger than 20% of the maximum torque, the process proceeds to step S2-3-2, in which the motor rotation speed Nm is set to 20 [rpm].
m] or more and the absolute value | Tn | is 20% or less of the maximum torque, the process proceeds to step S2-3-3. Step S2-3-2: Set the value k1 to the estimated temperature coefficient K and return. Step S2-3-3 The motor rotation speed Nm is 20 [r
pm] or more, and the absolute value | Tn |
It is determined whether it is not less than 0 [%] and less than 90 [%]. Motor rotation speed Nm is 20 [rpm]
Above, and the absolute value | Tn |
If not less than [%] and less than 90 [%], the process proceeds to step S2-3-4, in which the motor rotation speed Nm is set to 20%.
[Rpm], and when the absolute value | Tn | is 90% or more of the maximum torque or smaller than 80%, the process proceeds to step S2-3-5. Step S2-3-4: Set the value k2 to the estimated temperature coefficient K, and return. Step S2-3-5: The motor rotation speed Nm is 20 [r
pm] or more, and the absolute value | Tn |
It is determined whether it is 0 [%] or more. The motor rotation speed Nm is 20 [rpm] or more, and the absolute value | Tn |
Is greater than or equal to 90% of the maximum torque, step S
In 2-3-6, the motor rotation speed Nm is lower than 20 [rpm] and the absolute value | Tn |
If it is smaller than [%], the process proceeds to step S2-3-7. Step S2-3-6: Set the value k3 to the estimated temperature coefficient K, and return. Step S2-3-7: Set zero to the estimated temperature coefficient K and return.

Next, the subroutine of the heat radiation amount calculation processing in step S2-4 in FIG. 5 will be described.

In this case, the heat radiation amount R is preset for each region to which the motor rotational speed Nm and the required torque Tn belong, and the motor rotational speed Nm and the required torque Tn are associated with the heat radiation amount R in the memory. Is recorded as

The heat radiation amount calculating means determines that the absolute value | Tn | is 20% or less of the maximum torque, as shown in FIG.
It is determined whether or not it belongs to the area AR4 shown in FIG. When the absolute value | Tn | belongs to the area AR4, the heat radiation amount calculation processing unit sets the heat radiation amount R to the value q.

Subsequently, when the absolute value | Tn | does not belong to the area AR4, the heat radiation amount calculation processing means sets the motor rotation speed Nm to the second motor rotation speed threshold Nm _TH 2 (Nm _TH 2
> Nm _TH 1), 125 [rpm] in the present embodiment.
m] or more, and the absolute value | Tn |
[%] Or more, and the fourth required torque threshold value Tn _TH 4 (T
n _TH 2> Tn _TH 4> Tn _TH 1) In the present embodiment, it is determined whether or not the pixel belongs to an area AR5 smaller than 40 [%]. When the motor rotation speed Nm and the absolute value | Tn | belong to the area AR5, the heat radiation amount calculation processing means sets the heat radiation amount R to the value q.

The heat radiation amount calculation processing means determines that the motor rotation speed Nm and the absolute value | Tn |
If the motor rotation speed Nm does not belong to 5, the motor rotation speed Nm is equal to or higher than a third motor rotation speed threshold value Nm _TH 3 (Nm _TH 3> Nm _TH 2), 250 [rpm] in the present embodiment, and
The absolute value | Tn | is 40% or more of the maximum torque,
Fifth required torque threshold Tn _TH 5 (Tn _TH 2> Tn _TH 5>
Tn _TH 4), in the present embodiment, it is determined whether or not the pixel belongs to an area AR6 smaller than 60 [%]. When the motor rotation speed Nm and the absolute value | Tn | belong to the area AR6, the heat radiation amount calculation processing means sets the heat radiation amount R to a value q.

Further, the heat radiation amount calculation processing means determines that the motor rotation speed Nm and the absolute value | Tn |
If it does not belong to 6, the heat release amount R is set to zero.

As described above, in the heat radiation amount calculation processing,
When the absolute value | Tn | is 20% or less of the maximum torque, the motor rotation speed Nm is 125 [rpm] or more, and the absolute value | Tn | is 20% or more of the maximum torque and 40 [%] Or when the motor rotation speed Nm is 250 [rpm] or more, and the absolute value | Tn | is 40 [%] or more of the maximum torque and less than 60 [%]. Assuming R is the value q,
In other cases, the heat release amount R is assumed to be zero.

Next, the flowchart will be described. Step S2-4-1: It is determined whether or not the absolute value | Tn | is 20% or less of the maximum torque. Absolute value | T
If n | is 20% or less of the maximum torque, the absolute value | Tn |
If it is larger than [%], the process proceeds to step S2-4-3. Step S2-4-2: Set the value q to the heat release amount R and return. Step S2-4-3: Motor rotation speed Nm is 125
[Rpm], and whether the absolute value | Tn | is not less than 20 [%] of the maximum torque and less than 40 [%]. When the motor rotation speed Nm is 125 [r
pm] or more, and the absolute value | Tn |
If it is not less than 0 [%] and less than 40 [%], the process proceeds to step S2-4-2, in which the motor rotation speed is set to 125 [%].
If it is smaller than [rpm] and the absolute value | Tn | is 40% or more of the maximum torque or smaller than 20%, the process proceeds to step S2-4-4. Step S2-4-4: The motor rotation speed Nm is 250
[Rpm] and whether the absolute value | Tn | is 40% or more of the maximum torque and smaller than 60%. When the motor rotation speed Nm is 250 [r
pm] or more, and the absolute value | Tn |
If it is not less than 0 [%] and less than 60 [%], the process proceeds to step S2-4-2.
If it is smaller than [rpm] and the absolute value | Tn | is equal to or greater than 60 [%] of the maximum torque or smaller than 40 [%], the process proceeds to step S2-4-5. Step S2-4-5: Set the heat release amount R to zero and return.

Next, the subroutine of the offset temperature calculation processing in step S2-5 in FIG. 5 will be described.

[0073] In this case, the offset temperature to have been set in advance with respect to the DC voltage V _C, and the DC voltage V _C and the offset temperature to is recorded as being in correspondence table in the memory.

Since the capacitor 20 is disposed between the main relay 15 and the inverter 40 as described above, the driving of the electric vehicle is terminated and the driver turns off the ignition key (not shown). When the connection between the battery 14 and the capacitor 20 is cut off, the discharge starts, and the amount of charge decreases with time,
The DC voltage V _C decreases. That is, the DC voltage V
_C represents the state of the inverter 40 when the ignition key is turned on.

Further, as the driver turns off the ignition key, the transistors Tr1 to Tr6 are turned off, so that no heat is generated, and the inverter 40 emits heat spontaneously. The temperature gradually decreases.

If the driver turns off the ignition key and then turns it on again, instead of timing the time from turning off the ignition key to turning it on, the DC voltage V _C
And the longer the time from turning off to turning on, that is, the lower the DC voltage V _C , the lower the offset temperature to. Therefore,
When the driver turns off the ignition key and then turns it on again, the estimated temperature te can be accurately calculated. Further, since the DC voltage V _C can be used to calculate the offset temperature to, there is no need to provide a special sensor. Therefore, the cost of the motor drive device 10 can be reduced.

[0077] Therefore, the offset temperature calculation processing unit determines whether the ignition key is turned on, when the ignition key is turned on, reads the DC voltage V _C, and calculates an offset temperature-to.
In this case, the offset temperature calculation processing means, the DC voltage V _C is first DC voltage threshold V _{C TH} 1, in the present embodiment determines whether a 30 [V] or more, the DC voltage V _C Is equal to or higher than 30 [V], the offset temperature to is set to a value to1 (for example, 30 [° C.]). Also,
The offset temperature calculation processing means determines that the DC voltage V _C is 3
Lower than 0 [V], the second DC voltage threshold V _{C TH} 2, in the present embodiment determines whether a 10 [V] or more, the DC voltage V _C is below 30 V, 10 [V]
In the case of the above, the offset temperature to is set to the value to2 (to
2 <to1: For example, 20 ° C.). Then, the offset temperature calculation processing means, the DC voltage V _C is 10
[V], the offset temperature to is set to the value to3.
(To3 <to2: for example, 10 [° C.]).

When the offset temperature to is set in this way, the offset temperature calculation processing means turns on the main relay 15.

Next, the flowchart will be described. Step S2-5-1: It is determined whether or not the ignition key has been turned on. If the ignition key has been turned on, the process proceeds to step S2-5-2, and if the ignition key has not been turned on, the process returns. Step S2-5-2 read DC voltage V _C. Step S2-5-3 DC voltage V _C is determined whether a 30 [V] or more. DC voltage V _C is 30 [V]
If not, the process proceeds to step S2-5-4.
_{If C} is smaller than 30 [V], step S2-5-5
Proceed to. Step S2-5-4: Offset temperature to is set to value to1
Is set. Step S2-5-5 DC voltage V _C is determined whether a 10 [V] or more. DC voltage V _C is 10 [V]
If not, the process proceeds to step S2-5-6.
_{If C} is smaller than 10 [V], step S2-5-7
Proceed to. Step S2-5-6: Offset temperature to is set to value to2
Is set. Step S2-5-7: Offset temperature to is set to value to3
Is set. Step S2-5-8: Turn on the main relay 15,
To return.

Next, the subroutine of the stall determination process in step S3 of FIG. 4 will be described.

First, the stall determination processing means 94
Wait for the stall condition to be satisfied. For this purpose, the stall determination processing means 94 sets the absolute value | Tn | to a predetermined sixth required torque threshold Tn _TH 6 (this embodiment) with the first condition that the motor rotation speed Nm is zero. In the embodiment, the absolute value | Tn |
0 [%]), the stall condition is satisfied when both the first and second conditions are satisfied (Nm = 0 and | Tn |> Tn _TH 6). Judge that you have done. If at least one of the first and second conditions is not satisfied (Nm ≠ 0 or | Tn | ≦
It is determined that the stall condition is not satisfied at Tn _TH 6).

Further, when the stall condition is satisfied, the continuous stall time calculation processing means of the stall determination processing means 94 determines the time during which the stall condition is satisfied, ie,
The continuous stall time is calculated and recorded in a buffer (not shown). Therefore, when the stall condition is satisfied, the continuous stall time calculation processing means starts time counting by a timer (not shown), and performs time counting while the stall condition is satisfied. Then, the stall determination processing means 9
The accumulated stall time calculation processing means 4 determines whether the accumulated value of the continuous stall time recorded in the buffer, that is, whether the accumulated stall time is longer than 3 [seconds].
It should be noted that the continuous stall time allows the inverter 40
Is a stall state, and the continuous stall time calculation processing means forms a state value calculation processing means 91.

In FIG. 12, L1 is a line representing the absolute value | Tn |, and L2 is a line representing the first torque limit value ρ1. Then, as shown in FIG. 12, the absolute value | Tn |
Is greater than 50% of the maximum torque, the continuous stall time is the continuous stall time, and the sum of the times τ1 to τ3 is the cumulative stall time. Therefore, the stall determination process determines whether the total of the times τ1 to τ3 is longer than 3 [seconds].

The stall determination processing means 94
If the accumulated stall time is longer than 3 [seconds], it is determined that a stall state has occurred in the inverter 40, and a stall determination is made.

Next, the flowchart will be described. Step S3-1: Wait until the stall condition is satisfied. Step S3-2: It is determined whether or not the accumulated stall time is longer than 3 seconds. If the cumulative stall time is longer than 3 [seconds], the process proceeds to step S3-3, and if the cumulative stall time is 3 [seconds] or less, the process returns. Step S3-3: Make a stall determination and return.

Next, the subroutine of the torque limit calculation process in step S4 of FIG. 4 will be described.

In this case, the limiting torque calculation processing means 9
2 determines whether a stall determination has been made in the stall determination process as a first abnormality determination method,
When the stall determination is performed, the first torque limit value ρ1
Is set to 100 to β [%] of the maximum torque. For example, FIG.
As shown in FIG. 2, when the accumulated stall time becomes longer than 3 [seconds] at the timing t1, the limited torque calculation processing unit 92 performs a predetermined time from the timing t1.
At time t2 when 5 seconds have elapsed, the absolute value | Tn |
The first torque limit value ρ1 is gradually reduced so that is equal to 50% of the maximum torque. Then, the limit torque calculation processing means 92 determines whether or not the motor rotation speed Nm is zero at a timing t2, and determines whether the motor rotation speed Nm is zero.
Is not zero, that is, when the rotor is rotating, the first torque limit value ρ1 is maintained. When the motor rotation speed Nm is zero at the timing t2, the limited torque calculation processing means 92 sets the first torque limit value ρ1
Is further reduced.

When the motor rotation speed Nm becomes zero at the timing t3 while the first torque limit value ρ1 is maintained, the limiting torque calculation processing means 92 performs a predetermined time from the timing t3, for example, , 1.5 [seconds] have elapsed, the first torque limit value ρ1 is gradually reduced so that the absolute value | Tn | becomes 0% of the maximum torque. If the motor rotation speed Nm is not zero between the timings t3 and t5, the first torque limit value ρ1 is maintained.

Further, if the motor rotation speed Nm becomes zero at the timing t6 while maintaining the first torque limit value ρ1, the limit torque calculation processing means 92 sets
Is further reduced gradually. And
At timing t7, the absolute value | Tn |
[%], The first torque limit value ρ1 is gradually increased.

The limiting torque calculation processing means 92
Sets the first torque limit value ρ1 to 100% of the maximum torque when the stall determination is not performed in the stall determination process.

Next, the limit torque calculation processing means 92
Determines whether the estimated temperature te calculated in the estimated temperature calculation process is equal to or higher than 60 [° C.] as a second abnormality determination method. When the estimated temperature te is equal to or higher than 60 [° C.], FIG. , The second torque limit value ρ
2 is set to 80% of the maximum torque, and the estimated temperature te is 60%.
If the temperature is lower than [° C.], the second torque limit value ρ2 is set to 100% of the maximum torque.

Subsequently, the limiting torque calculation processing means 92
Determines, as a third abnormality determination method, whether the actual temperature is equal to or higher than 60 ° C., and if the actual temperature is equal to or higher than 60 ° C., the third torque limit value ρ3 corresponds to the actual temperature. And the actual torque is lower than 60 ° C., the third torque limit value ρ3 is set to 10% of the maximum torque.
Set to 0 [%]. As shown in FIG. 14, the value of γ is changed in response to the actual temperature changing between 60 ° C. and 80 ° C., and the third torque limit value becomes higher as the temperature becomes higher than 60 ° C. ρ3 is reduced. When the actual temperature reaches 80 ° C., the third torque limit value ρ3 is set to zero, and an alarm is generated by an alarm device (not shown).

When the first to third torque limit values ρ1 to ρ3 are calculated by the first to third abnormality determination methods in this way, the limit torque calculation processing means 92
The minimum value of the third torque limit values ρ1 to ρ3 is calculated as the limit torque.

When the required torque Tn is larger than the limit torque, the torque command value calculation processing means calculates the limit torque as a torque command value, and the current command value calculation processing means 96 outputs the d-axis current command value. The _ids and the q-axis current command value _iqs are calculated and sent to the motor control unit 45. As a result, when the first torque limit value ρ1 is calculated as the limit torque, stall control is performed in the motor control unit 45, and when the second torque limit value ρ2 is calculated as the limit torque, the motor control unit 45 , The estimated temperature control is performed, and when the third torque limit value ρ3 is calculated as the limited torque, the motor control unit 45 performs the actual temperature control.

Next, the flowchart will be described. Step S4-1: It is determined whether a stall determination has been made. If a stall determination is made, step S4
If no, the process proceeds to step S4-3. Step S4-2: Set 100 to β [%] of the maximum torque as the first torque limit value ρ1. Step S4-3: Set 100% of the maximum torque to the first torque limit value ρ1. Step S4-4: It is determined whether or not the estimated temperature te is equal to or higher than 60 [° C.]. If the estimated temperature te is equal to or higher than 60 ° C., the process proceeds to step S4-5, where
If it is lower than [° C.], the process proceeds to step S4-6. Step S4-5: The second torque limit value ρ2 is set to 80% of the maximum torque. Step S4-6: Set 100% of the maximum torque to the second torque limit value ρ2. Step S4-7: It is determined whether or not the actual temperature is equal to or higher than 60 [° C.]. If the actual temperature is higher than 60 ° C., the process proceeds to step S4-8, and if the actual temperature is lower than 60 ° C., the process proceeds to step S4-9. Step S4-8: The maximum torque γ [%] is set to the third torque limit value ρ3. Step S4-9: Set 100% of the maximum torque to the third torque limit value ρ3. Step S4-10 First to third torque limit values ρ1 to
The minimum value of ρ3 is set as the limiting torque, and the routine returns.

Incidentally, the first to third torque limit values ρ1
When the minimum value among ρ3 to ρ3 is calculated as the limit torque, the first to third abnormality determination methods are set for each of the motor rotation speed and the required torque when driving the motor 31, and the first to third abnormality determination methods are set. The torque limit can be reduced based on the three torque limit values ρ1 to ρ3.

FIG. 15 is a second diagram illustrating a region of the motor rotation speed and the required torque in the embodiment of the present invention. In the figure, the horizontal axis represents the motor rotation speed Nm,
The required torque Tn is plotted on the vertical axis.

For example, when the motor rotation speed Nm is equal to the first motor rotation speed threshold value Nm _TH 1, in the present embodiment, 20 m
[Rpm] and the absolute value | Tn | is equal to or greater than the second required torque threshold Tn _TH2 , which is 80% or more of the maximum torque in the present embodiment, the motor rotation speed N
m and the absolute value | Tn | belong to the area AR11. In this case, in the limit torque calculation process, the first torque limit value ρ1 is minimized, the first torque limit value ρ1 is calculated as the limit torque, and the motor control unit 45 (FIG. 2) performs stall control. .

Therefore, when the required torque Tn is large, such as when starting, climbing a hill, or suddenly accelerating, the temperatures of the transistors Tr1 to Tr6 rapidly increase, and the temperature of the inverter 40 also sharply increases. In this case, the abnormality of the inverter 40 can be quickly detected by the stall determination. As a result, the torque limit can be quickly reduced, and the temperature of inverter 40 can be reduced.

Further, the motor rotation speed Nm is equal to the first motor rotation speed threshold value Nm _TH 1, in this embodiment, 20 m.
[Rpm] and the absolute value | Tn | is equal to or greater than the second required torque threshold Tn _TH2 , which is 80% or more of the maximum torque in the present embodiment, the motor rotation speed Nm
And the absolute value | Tn | belong to the area AR12. In this case, in the limit torque calculation process, the second torque limit value ρ2 is minimized, the second torque limit value ρ2 is calculated as the limit torque, and the motor control unit 45 performs the estimated temperature control.

Therefore, when the temperature of the predetermined transistor rises and the temperature of the inverter 40 rises locally, even if the temperature sensor 22 is arranged at a position distant from the predetermined transistor, it is estimated that The abnormality of the inverter 40 can be reliably detected based on the temperature te. As a result, the limit torque can be reliably reduced, and the temperature of the inverter 40 can be lowered.

When the absolute value | Tn | is smaller than the second required torque threshold value Tn _TH 2, which is 80% of the maximum torque in this embodiment, the motor rotation speed Nm and the absolute value | Tn | It belongs to the area AR13. In this case, in the limit torque calculation process, the third torque limit value ρ3
Is minimized, the third torque limit value ρ3 is calculated as the limit torque, and the actual temperature control is performed in the motor control unit 45.

Therefore, the transistors Tr1 to Tr6
Even if the amount of heat radiated from each of the transistors Tr1 to Tr6 varies depending on the mounting state, the abnormality of the inverter 40 can be reliably detected based on the actual temperature. As a result, the limiting torque is reliably reduced, and the transistor Tr1
To Tr6 can be lowered.

The present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0105]

As described above in detail, according to the present invention, in the motor driving device, the power supply, the motor,
An inverter that converts a current supplied from the power supply into a phase current and supplies the phase current to the motor with the switching of the switching element, an inverter temperature detection unit that detects the temperature of the inverter as an actual temperature, and a state of the inverter. A state value calculation processing unit that calculates a state value to be represented; and a limit torque calculation processing unit that calculates a limit torque based on one of the actual temperature and the state value.

In this case, since the limit torque is calculated based on one of the actual temperature and the state value, when the required torque is large such as when starting, climbing up a hill, or suddenly accelerating, etc.
Although the temperature of each switching element rises sharply and the temperature of the inverter rises sharply, abnormality of the inverter can be quickly detected based on the state value. Therefore, the torque limit can be reduced quickly, and the temperature of the inverter can be lowered.

When the temperature of the predetermined switching element rises and the temperature of the inverter rises locally, the inverter temperature detecting means may be provided at a position distant from the predetermined switching element. In addition, the abnormality of the inverter can be reliably detected based on the state value. Therefore, the limiting torque can be reliably reduced, and the temperature of the inverter can be lowered.

Further, even if the amount of heat radiated from each switching element varies depending on the mounting state of the switching element, it is possible to reliably detect the abnormality of the inverter based on the actual temperature. Therefore, the limiting torque can be reliably reduced, and the temperature of the inverter can be lowered.

In another motor driving device of the present invention,
Further, the state value is a continuous stall time indicating that the inverter is in a stall state. The state value calculation processing means is a continuous stall time calculation processing means.

In this case, since the limit torque is calculated based on one of the actual temperature and the state value, when the required torque is large such as when starting, climbing up a hill, or suddenly accelerating, etc.
Although the temperature of each switching element rises sharply and the temperature of the inverter also rises sharply, an abnormality of the inverter can be quickly detected based on a continuous stall time indicating that the inverter is in a stall state. Therefore, the torque limit can be reduced quickly, and the temperature of the inverter can be lowered.

In still another motor drive device of the present invention, the state value is an estimated temperature representing the entire temperature of the inverter. The state value calculation processing means is an estimated temperature calculation processing means.

In this case, when the temperature of the predetermined switching element rises and the temperature of the inverter locally rises, an inverter temperature detecting means is provided at a position distant from the predetermined switching element. Also, the abnormality of the inverter can be reliably detected based on the estimated temperature representing the entire temperature of the inverter. Therefore,
It is possible to surely reduce the torque limit and lower the temperature of the inverter.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a motor drive device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a motor drive device according to an embodiment of the present invention.

FIG. 3 is a block diagram of a motor control unit according to the embodiment of the present invention.

FIG. 4 is a main flowchart showing the operation of the motor drive device according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating a subroutine of an estimated temperature calculating process according to the embodiment of the present invention.

FIG. 6 is a diagram showing a subroutine of an estimated temperature coefficient calculation process according to the embodiment of the present invention.

FIG. 7 is a diagram illustrating a subroutine of a heat radiation amount calculation process according to the embodiment of the present invention.

FIG. 8 is a diagram showing a subroutine of an offset temperature calculation process according to the embodiment of the present invention.

FIG. 9 shows the motor rotation speed and the rotation speed according to the embodiment of the present invention.
FIG. 5 is a first diagram illustrating a region of a required torque.

FIG. 10 is a diagram showing a subroutine of a stall determination process according to the embodiment of the present invention.

FIG. 11 is a diagram showing a subroutine of a torque limit calculation process in the embodiment of the present invention.

FIG. 12 is a time chart illustrating an operation of a stall determination process according to the embodiment of the present invention.

FIG. 13 is a diagram showing a relationship between a second torque limit value and an estimated temperature in the embodiment of the present invention.

FIG. 14 is a diagram showing a relationship between a third torque limit value and an actual temperature in the embodiment of the present invention.

FIG. 15 is a second diagram illustrating a region of a motor rotation speed and a required torque according to the embodiment of the present invention.

[Explanation of symbols]

10 the motor drive unit 14 battery 17 vehicle controller 22 temperature sensor 31 motor 40 inverter 91 status value calculation processing means 92 limit torque calculation processing means 93 estimates the temperature calculating device I _U, I _V, I _W current Tr1~Tr6 transistor

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H115 PC06 PI13 PI29 PU02 PU08 PV09 PV23 QE01 QE04 QE08 QN03 QN09 RB22 RB26 SE04 TB01 TO05 TO12 TO21 TO21 TO30 TR01 TU12 UI13 UI28 5H560 AA08 BB04 BB07 BB12 DA02 EB02 ECTT01 TT06 UA02 XA02 XA12 XA13

Claims (6)

[Claims] 1. A power supply, a motor, and an inverter that converts a current supplied from the power supply into a phase current and supplies the phase current to the motor with switching of a switching element.
Inverter temperature detection means for detecting the temperature of the inverter as an actual temperature; state value calculation processing means for calculating a state value representing the state of the inverter; and calculating a limit torque based on one of the actual temperature and the state value. A motor drive device comprising: 2. The motor drive device according to claim 1, wherein the state value is a continuous stall time indicating that the inverter is in a stall state, and the state value calculation processing means is a continuous stall time calculation processing means. 3. The motor drive device according to claim 1, wherein the state value is an estimated temperature representing an entire temperature of the inverter, and the state value calculation processing means is an estimated temperature calculation processing means. 4. The continuous stall time calculating means includes: a continuous stall time indicating that the inverter is in a stall state; and an estimated temperature indicating an entire temperature of the inverter. 2. The motor drive device according to claim 1, wherein the motor drive device is an estimated temperature calculation processing unit. 5. The estimated temperature calculation processing means calculates a temperature correction value corresponding to a state of the inverter, and calculates the estimated temperature based on the actual temperature detected at a predetermined timing and the temperature correction value. Claim 3 or 4 which calculates.
3. The motor drive device according to claim 1. 6. In accordance with switching of a switching element constituting an inverter, a current supplied from a power supply is converted into a phase current and supplied to a motor, and the temperature of the inverter is detected as an actual temperature to indicate a state of the inverter. A motor driving method comprising: calculating a state value; and calculating a limit torque based on one of the actual temperature and the state value.