JP2009261182A - Magnet temperature estimating device for rotating electric machine and electric vehicle equipped with the same, and method of estimating magnet temperature for the rotating electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnet temperature estimating device for a rotating electric machine, capable of estimating the magnet temperature more easily. <P>SOLUTION: A torque measuring part 120 measures an actual torque of a motor generator. A torque estimating part 122 estimates the torque of the motor generator, when the magneto temperature of the motor generator is a reference temperature, by using a current-torque map created beforehand. A magnet temperature estimating part 126 estimates the magnet temperature of the motor generator based on the difference of a measuring torque Ta and an estimating torque Te, by using a magnet temperature estimating map created beforehand based on a temperature characteristics of a permanent magnet. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnet temperature estimation device for a rotating electrical machine, an electric vehicle equipped with the same, and a magnet temperature estimation method for the rotating electrical machine, and in particular, a magnet temperature of a permanent magnet type rotating electrical machine including a field permanent magnet in a rotor. It is related with the estimation technique.

  Japanese Patent Laying-Open No. 2007-68354 (Patent Document 1) discloses a control device for a permanent magnet type rotating electrical machine. In this control device, the magnet temperature of the permanent magnet at the time of energization is estimated based on the field weakening current amount at the time of energization of the stator winding and the torque, rotation speed, and power supply voltage of the permanent magnet type rotating electrical machine. .

According to this control device, the temperature of the permanent magnet is accurately estimated, and the output of the permanent magnet type rotating electrical machine is appropriately controlled based on the estimated magnet temperature (see Patent Document 1).
JP 2007-68354 A

  However, in the magnet temperature estimation method disclosed in the above Japanese Patent Application Laid-Open No. 2007-68354, many parameters including the field weakening current amount, torque, rotation speed, and power supply voltage are measured while changing the magnet temperature. Since a map for estimating the magnet temperature is created, a large amount of labor is required for creating the map.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a magnet temperature estimation device for a rotating electrical machine that can more easily estimate the magnet temperature and an electric vehicle equipped with the same.

  Another object of the present invention is to provide a magnet temperature estimation method for a rotating electrical machine that can more easily estimate the magnet temperature.

  According to this invention, the magnet temperature estimating device for a rotating electrical machine is a magnet temperature estimating device for a rotating electrical machine including a rotor having a permanent magnet, and includes a torque estimating unit, a torque measuring unit, a computing unit, and a magnet. A temperature estimation unit. The torque estimating unit estimates the torque of the rotating electrical machine based on the current flowing through the rotating electrical machine using the relationship between the current of the rotating electrical machine and the torque measured in advance when the permanent magnet is at a predetermined temperature. The torque measuring unit measures the torque of the rotating electrical machine. The computing unit calculates a difference between the measured torque measured by the torque measuring unit and the estimated torque estimated by the torque estimating unit. The magnet temperature estimation unit estimates the temperature of the permanent magnet based on the calculation result of the calculation unit, using a predetermined relationship between the measured torque and the difference between the estimated torque and the temperature of the permanent magnet.

  Preferably, the magnet temperature estimation unit estimates the temperature of the permanent magnet based on the calculation result of the calculation unit, using a map indicating the relationship between the measured torque and the difference between the estimated torque and the temperature of the permanent magnet. The map is created in advance by determining the relationship between the temperature difference of the permanent magnet based on a predetermined temperature and the torque change of the rotating electrical machine due to the temperature difference based on the temperature characteristics of the permanent magnet.

  Preferably, the torque measuring unit measures the torque of the rotating electrical machine based on the electric power applied to the rotating electrical machine and the rotational speed of the rotating electrical machine.

  Preferably, the magnet temperature estimation device for a rotating electrical machine further includes a torque limiting unit. The torque limiting unit limits the torque of the rotating electrical machine based on the temperature of the permanent magnet estimated by the magnet temperature estimation unit.

  Preferably, the magnet temperature estimation device for a rotating electrical machine further includes an abnormality detection unit. The abnormality detection unit detects an abnormality of the rotating electrical machine based on the temperature of the permanent magnet estimated by the magnet temperature estimation unit.

  Preferably, the magnet temperature estimation device for a rotating electrical machine further includes a torque correction unit. The torque correction unit corrects the torque of the rotating electrical machine based on the temperature of the permanent magnet estimated by the magnet temperature estimation unit.

  According to the invention, the electric vehicle includes the rotating electric machine and the magnet temperature estimating device. The rotating electrical machine includes a rotor having a permanent magnet, and the rotating shaft is coupled to the drive shaft of the vehicle. The magnet temperature estimation device is a magnet temperature estimation device for any one of the rotating electrical machines described above.

  According to the invention, the magnet temperature estimation method for a rotating electrical machine is a magnet temperature estimation method for a rotating electrical machine including a rotor having a permanent magnet, and is measured in advance when the permanent magnet is at a predetermined temperature. The step of estimating the torque of the rotating electrical machine based on the current flowing through the rotating electrical machine using the relationship between the current and torque of the rotating electrical machine, the step of measuring the torque of the rotating electrical machine, the measured torque and the rotating electrical machine The difference between the measured torque and the estimated torque is calculated using the step of calculating the difference between the estimated torque estimated based on the current flowing through the current and the predetermined relationship between the measured torque and the estimated torque difference and the temperature of the permanent magnet. Estimating the temperature of the permanent magnet based on the calculation result of the step of calculating.

  Preferably, in the step of estimating the temperature of the permanent magnet, the calculation result of the step of calculating the difference between the measured torque and the estimated torque is calculated using a map indicating the relationship between the measured torque and the difference between the estimated torque and the temperature of the permanent magnet. Based on this, the temperature of the permanent magnet is estimated. The map is created in advance by determining the relationship between the temperature difference of the permanent magnet based on a predetermined temperature and the torque change of the rotating electrical machine due to the temperature difference based on the temperature characteristics of the permanent magnet.

  Preferably, in the step of measuring the torque, the torque of the rotating electrical machine is measured based on the electric power applied to the rotating electrical machine and the rotational speed of the rotating electrical machine.

  Preferably, the magnet temperature estimation method of the rotating electrical machine further includes a step of limiting the torque of the rotating electrical machine based on the temperature of the permanent magnet estimated in the step of estimating the temperature of the permanent magnet.

  Preferably, the magnet temperature estimation method of the rotating electrical machine further includes a step of detecting an abnormality of the rotating electrical machine based on the temperature of the permanent magnet estimated in the step of estimating the temperature of the permanent magnet.

  Preferably, the magnet temperature estimation method of the rotating electrical machine further includes a step of correcting the torque of the rotating electrical machine based on the temperature of the permanent magnet estimated in the step of estimating the temperature of the permanent magnet.

  In this invention, when the permanent magnet of the rotor is at a predetermined temperature, the relationship between the current of the rotating electrical machine and the torque is measured in advance, and the torque of the rotating electrical machine is calculated based on the current flowing through the rotating electrical machine using the relationship. Presumed. Further, the torque of the rotating electrical machine is measured, and the difference between the measured torque and the estimated torque is calculated. The temperature of the permanent magnet is estimated based on the calculation result of the difference between the measured torque and the estimated torque, using a predetermined relationship between the difference between the measured torque and the estimated torque and the temperature of the permanent magnet. As described above, the temperature of the permanent magnet is estimated using a predetermined relationship between the difference between the measured torque and the estimated torque and the temperature of the permanent magnet. When obtaining this relationship, the temperature is measured while changing the magnet temperature. The number of parameters (the amount of torque change from the estimated torque indicating the torque when the permanent magnet is at a predetermined temperature) can be reduced. Therefore, according to the present invention, the magnet temperature of the rotating electrical machine can be easily estimated.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is an electric circuit diagram of an electric vehicle equipped with a magnet temperature estimation device according to Embodiment 1 of the present invention. Referring to FIG. 1, electrically powered vehicle 100 includes power storage device 10, inverter 20, motor generator 28, control device 30, positive line PL, negative line NL, capacitor C, voltage sensor 44, A current sensor 46 and a rotation angle sensor 48 are provided.

  The power storage device 10 is composed of a secondary battery such as nickel metal hydride or lithium ion, and stores electric power for vehicle travel. Power storage device 10 is connected to positive electrode line PL and negative electrode line NL, and supplies power to inverter 20 via positive electrode line PL and negative electrode line NL. Further, during power regeneration by motor generator 28 such as when the vehicle is braked, power storage device 10 is charged by receiving electric power generated by motor generator 28 from inverter 20. Note that a large-capacity capacitor may be employed as the power storage device 10.

  Capacitor C is connected between positive electrode line PL and negative electrode line NL, and smoothes a voltage fluctuation component between positive electrode line PL and negative electrode line NL. Voltage sensor 44 detects the voltage across capacitor C, that is, voltage VH between positive electrode line PL and negative electrode line NL, and outputs the detected value to control device 30.

  Inverter 20 includes a U-phase arm 22, a V-phase arm 24, and a W-phase arm 26. U-phase arm 22, V-phase arm 24, and W-phase arm 26 are connected in parallel between positive electrode line PL and negative electrode line NL. Each phase arm includes a switching element connected in series between positive electrode line PL and negative electrode line NL, and a diode connected in antiparallel to each switching element. U-phase arm 22 is connected to the U-phase coil of motor generator 28, and V-phase arm 24 and W-phase arm 26 are connected to the V-phase coil and W-phase coil of motor generator 28, respectively.

  In addition, as a switching element which comprises each phase arm, IGBT (Insulated Gate Bipolar Transistor), power MOSFET (Metal Oxide Semiconductor Field-Effect Transistor), etc. can be used, for example.

  Inverter 20 receives electric power from power storage device 10 through positive electrode line PL and negative electrode line NL, and drives motor generator 28 based on signal PWI from control device 30. Inverter 20 also converts the regenerative power generated by motor generator 28 into a voltage and outputs it to power storage device 10 when the vehicle is braked.

  Motor generator 28 is made of a permanent magnet type rotating electrical machine, and is made of, for example, a three-phase AC synchronous motor including a rotor having a permanent magnet embedded therein and a stator having a three-phase coil connected to inverter 20. Motor generator 28 is driven by inverter 20 to generate a driving force of the vehicle and output it to a drive shaft (not shown). In addition, when the vehicle is braked, the motor generator 28 receives the kinetic energy of the vehicle from the drive shaft and generates power, and outputs the generated power to the inverter 20. The permanent magnet of the rotor may be mounted on the surface of the rotor.

  Current sensor 46 detects motor current I flowing through motor generator 28 and outputs the detected value to control device 30. In FIG. 1, the U-phase current and the V-phase current are detected by the current sensor 46, but the W-phase current is calculated using Kirchoff's law based on the detected U-phase current and V-phase current. Can do. Note that the U-phase current and the W-phase current may be detected by the current sensor 46, or the V-phase current and the W-phase current may be detected. The rotation angle sensor 48 detects the rotation angle θ of the rotor of the motor generator 28 and outputs the detected value to the control device 30.

  Control device 30 is a signal for driving motor generator 28 based on torque command value TR received from a vehicle ECU (Electronic Control Unit) (not shown) and detected values of voltage VH, motor current I, and rotation angle θ. PWI is generated, and the generated signal PWI is output to inverter 20.

  Control device 30 estimates the temperature of the permanent magnet of motor generator 28 by a method described later. That is, since it is difficult to directly measure the temperature of the permanent magnet in a state where the motor generator 28 is mounted on the electric vehicle 100, the control device 30 estimates the temperature of the permanent magnet by a method described later. The reason for estimating the temperature of the permanent magnet is that if the temperature of the rotor rises as the temperature of the motor generator 28 rises, the permanent magnet is demagnetized, so that the motor generator 28 cannot obtain a desired output. . In other words, the accuracy of control of the motor generator 28 can be improved by accurately estimating the temperature of the permanent magnet.

  FIG. 2 is a functional block diagram of the control device 30 shown in FIG. Referring to FIG. 2, control device 30 includes loss correction unit 102, current command generation unit 104, proportional integration (PI) control units 106 and 108, dq / three-phase conversion unit 110, and drive signal generation unit. 112 and a three-phase / dq converter 114. In addition, the control device 30 includes an input power calculation unit 118, a torque measurement unit 120, a torque estimation unit 122, a subtraction unit 124, a magnet temperature estimation unit 126, a torque limiting unit 128, and a differential calculation unit 116. In addition.

  The loss correction unit 102 performs loss correction of the torque command value TR based on the torque command value TR and the rotation speed ω calculated by the differential calculation unit 116 based on the rotation angle θ. Specifically, as the rotational speed increases, the relationship between torque and current changes due to an increase in iron loss, so the torque command value TR is corrected by the rotational speed ω.

  The current command generation unit 104 is a map showing the relationship between the torque (d-axis current and q-axis current) of the motor generator 28 measured when the rotational speed of the motor generator 28 (FIG. 1) is a constant value and the torque. The d-axis current command value Id * and the q-axis current command value Iq * are generated based on the torque command value corrected by the loss by the loss correction unit 102.

  The three-phase / dq converter 114 uses the rotation angle θ from the rotation angle sensor 48 (FIG. 1) to convert the motor current I (three-phase current) detected by the current sensor 46 into the d-axis current measurement values Id and q. It converts into the shaft current measurement value Iq.

  The PI control unit 106 receives the difference between the d-axis current command value Id * generated by the current command generation unit 104 and the d-axis current measurement value Id output from the three-phase / dq conversion unit 114 as a proportional integral calculation. And outputs the calculation result to the dq / three-phase conversion unit 110. Further, the PI control unit 108 is proportional to the difference between the q-axis current command value Iq * generated by the current command generation unit 104 and the q-axis current measurement value Iq output from the three-phase / dq conversion unit 114 as an input. The integration calculation is performed, and the calculation result is output to the dq / three-phase conversion unit 110.

  The dq / three-phase conversion unit 110 uses the rotation angle θ from the rotation angle sensor 48 to convert the voltage command values on the d and q axes received from the PI control units 106 and 108, respectively, into U-phase voltage command values Vu * and Vu. The phase voltage command value Vv * and the W phase voltage command value Vw * are converted and output to the drive signal generation unit 112. The voltage command values Vu *, Vv *, and Vw * are also output to the input power calculation unit 118 described later.

  Drive signal generator 112 drives for driving U-phase arm 22, V-phase arm 24, and W-phase arm 26 of inverter 20 (FIG. 1) based on voltage command values Vu *, Vv *, and Vw *, respectively. Signals Du, Dv, and Dw are generated. As an example, the drive signal generation unit 112 generates a PWM (Pulse Width Modulation) signal based on the voltage command values Vu *, Vv *, Vw * and a carrier wave (carrier wave) generated by an oscillation unit (not shown). The generated PWM signals are output to the inverter 20 as drive signals Du, Dv, Dw.

  Thereby, each phase arm of inverter 20 is switching-controlled in accordance with drive signals Du, Dv, Dw, and the current flowing through each phase coil of motor generator 28 is controlled. In this way, the motor current I is controlled, and a desired torque is generated in the motor generator 28.

  Input power calculation unit 118, torque measurement unit 120, torque estimation unit 122, subtraction unit 124, and magnet temperature estimation unit 126 constitute a magnet temperature estimation unit that estimates the temperature of the permanent magnet of motor generator 28.

  Input power calculation unit 118 receives voltage command values Vu *, Vv *, Vw * from dq / three-phase conversion unit 110, and receives a detected value of motor current I from current sensor 46 (FIG. 1). Input power calculation unit 118 calculates input power Pin of motor generator 28 based on these voltage command values and motor current I, and outputs the calculation result to torque measurement unit 120. A voltage sensor may be provided to detect each phase voltage, and the detected value of each phase voltage may be used in place of the voltage command values Vu *, Vv *, and Vw *. The differential calculation unit 116 performs differential calculation on the rotation angle θ from the rotation angle sensor 48 to calculate the rotation speed ω of the motor generator 28.

  Torque measurement unit 120 measures torque of motor generator 28 using the following equation based on input power Pin of motor generator 28 calculated by input power calculation unit 118 and rotation speed ω calculated by differential operation unit 116. To do.

Measurement torque Ta = (Pin × η) / ω (1)
Here, η is motor efficiency and is measured in advance. The measured torque Ta indicates the actual torque of the motor generator 28 calculated based on the actual results of the input power and the rotational speed of the motor generator 28.

  On the other hand, the torque estimation unit 122 uses a current-torque map created in advance to generate a motor generator 28 based on the d-axis current measurement value Id and the q-axis current measurement value Iq output from the three-phase / dq conversion unit 114. Estimate the torque. Here, the current-torque map is created from data of current and torque measured when the magnet temperature of the motor generator 28 is a certain constant temperature. Therefore, the estimated torque Te estimated by the torque estimating unit 122 is an estimate of the torque of the motor generator 28 when the magnet temperature is a certain temperature (reference temperature).

  The subtracting unit 124 subtracts the estimated torque Te estimated by the torque estimating unit 122 from the measured torque Ta measured by the torque measuring unit 120 and outputs the calculation result to the magnet temperature estimating unit 126. The difference between the measured torque Ta and the estimated torque Te calculated by the subtracting unit 124 indicates the torque change of the motor generator 28 caused by the change in the magnet temperature of the motor generator 28 from the reference temperature.

  The magnet temperature estimation unit 126 estimates the magnet temperature of the rotor based on the calculation result of the subtraction unit 124 (difference between the measured torque Ta and the estimated torque Te) using a magnet temperature estimation map created in advance. Here, the magnet temperature estimation map uses the temperature characteristics of the permanent magnet of the motor generator 28 to obtain the relationship between the temperature difference of the permanent magnet from the reference temperature and the torque change of the motor generator 28 due to the temperature difference. Created in advance.

  More specifically, since the amount of magnetic flux change due to a change in magnet temperature is known from the temperature characteristic data of the permanent magnet, the change in torque of the motor generator 28 due to the temperature change of the permanent magnet can be obtained using this temperature characteristic. Therefore, the relationship between the measured torque Ta and the estimated torque Te is obtained by obtaining the relationship between the magnet temperature and the amount of torque change with reference to the reference temperature when the current-torque map used in the torque estimating unit 122 is created. A magnet temperature estimation map for estimating the magnet temperature can be created.

  FIG. 3 is a diagram showing an example of a magnet temperature estimation map. Referring to FIG. 3, when the difference between measured torque Ta and estimated torque Te is zero, the magnet temperature is estimated to be reference temperature TEMP0. When the difference is negative, that is, when the measured torque Ta indicating the actual torque is smaller than the estimated torque Te indicating the torque when the magnet temperature is the reference temperature TEMP0, the magnet temperature is lower than the reference temperature TEMP0. When the difference is positive, the magnet temperature is estimated to be lower than the reference temperature TEMP0.

  In FIG. 3, the relationship between the difference between the measured torque Ta and the estimated torque Te and the magnet temperature is shown as linear, but this relationship depends on the temperature characteristic data of the permanent magnet. The relationship is not limited to that shown in FIG.

  Referring again to FIG. 2, torque limiter 128 limits the torque of motor generator 28 based on magnet temperature TEMP estimated by magnet temperature estimator 126. More specifically, torque limiter 128 outputs a torque limit command for limiting the torque of motor generator 28 when estimated magnet temperature TEMP exceeds a predetermined temperature. The torque of motor generator 28 is limited by limiting torque command value TR using this torque limit command.

  In the control device 30, the actual torque of the motor generator 28 is measured by the torque measuring unit 120. Further, the torque estimating unit 122 estimates the torque of the motor generator 28 when it is assumed that the magnet temperature of the motor generator 28 is a certain reference temperature TEMP0. Then, the difference between the measured torque Ta and the estimated torque Te is calculated by the subtractor 124, and the magnet temperature estimator 126 uses the magnet temperature estimation map created in advance using the temperature characteristics of the permanent magnet to use the subtractor 124. Based on the calculation result, the magnet temperature of the motor generator 28 is estimated.

  FIG. 4 is a flowchart showing a flow of a magnet temperature estimation process by the control device 30 shown in FIG. Note that the processing shown in this flowchart is executed at regular time intervals or whenever a predetermined condition is satisfied. Referring to FIG. 4, control device 30 converts the detected value of motor current I (three-phase current) from current sensor 46 (FIG. 1) into d-axis current measurement value Id and q-axis current measurement value Iq ( Step S10).

  Next, control device 30 calculates in step S10 using the above-described current-torque map created in advance based on the current and torque data measured when the magnet temperature of motor generator 28 is a certain constant temperature. The torque of motor generator 28 is estimated based on d-axis current measurement value Id and q-axis current measurement value Iq (step S20).

  Subsequently, control device 30 measures input power Pin of motor generator 28 (step S30). For example, control device 30 can calculate input power Pin based on each phase voltage command value and motor current I detected by current sensor 46. Alternatively, instead of each phase voltage command value, a voltage sensor may be provided and the detected value of each phase voltage may be used.

  And the control apparatus 30 is based on the input electric power Pin measured in step S30, and rotational speed (omega) obtained by differentiating rotational angle (theta) from the rotational angle sensor 48 (FIG. 1), and the type | formula mentioned above. The torque of motor generator 28 is measured using (1) (step S40).

  Next, the control device 30 calculates a difference between the measured torque Ta measured in step S40 and the estimated torque Te estimated in step S20 (step S50). Then, control device 30 estimates the magnet temperature of motor generator 28 based on the calculation result in step S50, using the above-described magnet temperature estimation map created in advance using the temperature characteristic data of the permanent magnet of motor generator 28. (Step S60).

  Further, control device 30 limits the torque of motor generator 28 based on the estimated magnet temperature TEMP (step S70). Specifically, control device 30 limits torque of motor generator 28 by limiting torque command value TR when estimated magnet temperature TEMP exceeds a predetermined temperature.

  As described above, in the first embodiment, the current-torque map created in advance based on the current and torque data measured when the magnet temperature of the motor generator 28 is the reference temperature TEMP0 is used. Torque of motor generator 28 is estimated based on measured shaft current value Id and measured q-axis current value Iq. Further, the actual torque of motor generator 28 is measured based on input power Pin and rotational speed ω of motor generator 28, and the difference between measured torque Ta and estimated torque Te is calculated. Then, by using the temperature characteristics of the permanent magnet, a relationship between the temperature difference of the permanent magnet from the reference temperature TEMP0 and the torque change of the motor generator 28 due to the temperature difference is used, and a magnet temperature estimation map prepared in advance is used. The temperature of the permanent magnet is estimated based on the calculation result of the difference between the measured torque Ta and the estimated torque Te.

  In this way, the temperature of the permanent magnet is estimated using the magnet temperature estimation map. When creating this magnet temperature estimation map, parameters to be measured while changing the magnet temperature (the temperature of the permanent magnet is the reference temperature). The number of torque changes from the estimated torque indicating the torque at TEMP0 can be reduced. Therefore, according to the first embodiment, the magnet temperature of motor generator 28 can be easily estimated.

  Further, according to the first embodiment, since the torque of motor generator 28 is limited based on the estimated magnet temperature, it is possible to prevent motor generator 28 from overheating.

[Embodiment 2]
FIG. 5 is a functional block diagram of the control device according to the second embodiment. Referring to FIG. 5, control device 30A includes an abnormality detecting unit 130 instead of torque limiting unit 128 in the configuration of control device 30 in the first embodiment shown in FIG.

  Abnormality detection unit 130 detects an abnormality in motor generator 28 based on magnet temperature TEMP estimated by magnet temperature estimation unit 126. More specifically, when the estimated magnet temperature TEMP exceeds a predetermined temperature, the abnormality detection unit 130 determines that the motor generator 28 is abnormal and outputs a signal ARM for notifying an alarm.

  The other configuration of control device 30A is the same as that of control device 30 in the first embodiment.

  FIG. 6 is a flowchart showing a flow of a magnet temperature estimation process performed by control device 30A in the second embodiment. Note that the processing shown in this flowchart is also executed at regular time intervals or whenever a predetermined condition is satisfied. Referring to FIG. 6, this flowchart includes step S72 instead of step S70 in the flowchart shown in FIG.

  That is, when the magnet temperature of motor generator 28 is estimated in step S60, control device 30A determines the presence or absence of abnormality of motor generator 28 based on the estimated magnet temperature TEMP by the method described above (step S72). When abnormality of motor generator 28 is detected, control device 30A outputs an alarm.

  As described above, according to the second embodiment, the magnet temperature of motor generator 28 is estimated, and abnormality of motor generator 28 is detected based on the estimated magnet temperature. Etc. can be detected appropriately.

[Embodiment 3]
FIG. 7 is a functional block diagram of the control device according to the third embodiment. Referring to FIG. 7, control device 30 </ b> B includes a torque correction unit 132 instead of torque limiting unit 128 in the configuration of control device 30 in the first embodiment shown in FIG. 1.

  Torque correction unit 132 corrects the torque of motor generator 28 based on magnet temperature TEMP estimated by magnet temperature estimation unit 126. More specifically, as described above, when the magnet temperature changes, the torque of the motor generator 28 changes, and an error corresponding to the magnet temperature occurs with respect to the torque command value TR. Therefore, the torque correction unit 132 corrects the torque of the motor generator 28 based on the estimated magnet temperature TEMP in order to improve the torque control accuracy. As an example, the torque correction unit 132 obtains a torque correction value of the motor generator 28 from a map or the like based on the estimated magnet temperature TEMP, and corrects the torque command value TR with this torque correction value, thereby correcting the motor generator 28. Correct the torque.

  The other configuration of control device 30B is the same as that of control device 30 in the first embodiment.

  FIG. 8 is a flowchart showing a flow of a magnet temperature estimation process performed by control device 30B in the third embodiment. Note that the processing shown in this flowchart is also executed at regular time intervals or whenever a predetermined condition is satisfied. Referring to FIG. 8, this flowchart includes step S74 in place of step S70 in the flowchart shown in FIG.

  That is, when the magnet temperature of motor generator 28 is estimated in step S60, control device 30B corrects the torque of motor generator 28 based on the estimated magnet temperature TEMP by the method described above (step S74).

  As described above, according to the third embodiment, since the magnet temperature of motor generator 28 is estimated and the torque of motor generator 28 is corrected based on the estimated magnet temperature, the torque control of motor generator 28 is controlled. Accuracy can be improved.

  In each of the above embodiments, the torque measurement unit 120 measures the torque of the motor generator 28 using the formula (1). However, a torque sensor is provided to measure the torque of the motor generator 28. Also good.

  In each of the above embodiments, a boost converter that adjusts the input voltage of inverter 20 to a voltage equal to or higher than the voltage of power storage device 10 may be provided between power storage device 10 and inverter 20.

  The present invention is applied to all electric vehicles such as an electric vehicle using only the motor generator 28 as a power source, a hybrid vehicle further including an engine as a power source, and a fuel cell vehicle including a fuel cell as a power source for driving the vehicle. Applicable.

  In the above, motor generator 28 corresponds to an example of “rotary electric machine” in the present invention, and subtracting unit 124 corresponds to an example of “calculating unit” in the present invention.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

1 is an electric circuit diagram of an electric vehicle equipped with a magnet temperature estimation device according to Embodiment 1 of the present invention. It is a functional block diagram of the control apparatus shown in FIG. It is the figure which showed the torque difference-magnet temperature map. It is a flowchart which shows the flow of the estimation process of the magnet temperature by the control apparatus shown in FIG. 6 is a functional block diagram of a control device according to Embodiment 2. FIG. 6 is a flowchart showing a flow of magnet temperature estimation processing by the control device in the second embodiment. FIG. 10 is a functional block diagram of a control device in a third embodiment. 10 is a flowchart illustrating a flow of a magnet temperature estimation process performed by a control device according to Embodiment 3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Power storage device, 20 Inverter, 22 U-phase arm, 24 V-phase arm, 26 W-phase arm, 28 Motor generator, 30 Control device, 44 Voltage sensor, 46 Current sensor, 48 Rotation angle sensor, 100 Electric vehicle, 102 Loss correction Unit, 104 current command generation unit, 106, 108 PI control unit, 110 dq / three-phase conversion unit, 112 drive signal generation unit, 114 three-phase / dq conversion unit, 116 differentiation calculation unit, 118 input power calculation unit, 120 torque Measurement unit, 122 Torque estimation unit, 124 Subtraction unit, 126 Magnet temperature estimation unit, 128 Torque limit unit, 130 Abnormality detection unit, 132 Torque correction unit, PL positive line, NL negative line, C capacitor

Claims (13)

A magnet temperature estimation device for a rotating electrical machine including a rotor having a permanent magnet,
A torque estimation unit that estimates the torque of the rotating electrical machine based on the current flowing through the rotating electrical machine using the relationship between the current and torque of the rotating electrical machine measured in advance when the permanent magnet is at a predetermined temperature;
A torque measuring unit for measuring the torque of the rotating electrical machine;
An arithmetic unit that calculates a difference between the measured torque measured by the torque measuring unit and the estimated torque estimated by the torque estimating unit;
A magnet temperature estimator that estimates a temperature of the permanent magnet based on a calculation result of the calculator using a predetermined relationship between the difference between the measured torque and the estimated torque and the temperature of the permanent magnet; A magnet temperature estimation device for a rotating electrical machine. The magnet temperature estimation unit estimates the temperature of the permanent magnet based on the calculation result of the calculation unit, using a map showing a relationship between the measured torque and the difference between the estimated torque and the temperature of the permanent magnet,
The map is created in advance by determining a relationship between a temperature difference of the permanent magnet based on the predetermined temperature and a torque change of the rotating electrical machine due to the temperature difference based on the temperature characteristics of the permanent magnet. The apparatus for estimating a magnet temperature of a rotating electrical machine according to claim 1.   3. The magnet temperature estimating device for a rotating electrical machine according to claim 1, wherein the torque measuring unit measures the torque of the rotating electrical machine based on electric power given to the rotating electrical machine and a rotational speed of the rotating electrical machine. .   4. The rotating electrical machine according to claim 1, further comprising a torque limiting unit that limits a torque of the rotating electrical machine based on the temperature of the permanent magnet estimated by the magnet temperature estimating unit. 5. Magnet temperature estimation device.   4. The rotating electrical machine according to claim 1, further comprising an abnormality detection unit that detects an abnormality of the rotating electrical machine based on the temperature of the permanent magnet estimated by the magnet temperature estimation unit. 5. Magnet temperature estimation device.   4. The rotating electrical machine according to claim 1, further comprising a torque correcting unit that corrects the torque of the rotating electrical machine based on the temperature of the permanent magnet estimated by the magnet temperature estimating unit. 5. Magnet temperature estimation device. A rotating electrical machine including a rotor having a permanent magnet and having a rotating shaft coupled to a drive shaft of the vehicle;
An electric vehicle provided with the magnet temperature estimation apparatus of a rotary electric machine of any one of Claims 1-6. A method for estimating a magnet temperature of a rotating electrical machine including a rotor having a permanent magnet,
Estimating the torque of the rotating electrical machine based on the current flowing in the rotating electrical machine using the relationship between the current and torque of the rotating electrical machine measured in advance when the permanent magnet is at a predetermined temperature;
Measuring the torque of the rotating electrical machine;
Calculating a difference between the measured torque measured and an estimated torque estimated based on a current flowing through the rotating electrical machine;
Estimating the temperature of the permanent magnet based on the calculation result of the step of calculating the difference using a predetermined relationship between the difference between the measured torque and the estimated torque and the temperature of the permanent magnet. The method for estimating the magnet temperature of a rotating electrical machine. In the step of estimating the temperature of the permanent magnet, the permanent torque is calculated based on a calculation result of the step of calculating the difference using a map indicating a relationship between the measured torque and the difference between the estimated torque and the temperature of the permanent magnet. The temperature of the magnet is estimated,
The map is created in advance by determining a relationship between a temperature difference of the permanent magnet based on the predetermined temperature and a torque change of the rotating electrical machine due to the temperature difference based on the temperature characteristics of the permanent magnet. The method for estimating a magnet temperature of a rotating electrical machine according to claim 8.   The magnet of the rotating electrical machine according to claim 8 or 9, wherein in the step of measuring the torque, the torque of the rotating electrical machine is measured based on electric power applied to the rotating electrical machine and a rotation speed of the rotating electrical machine. Temperature estimation method.   The rotation according to any one of claims 8 to 10, further comprising a step of limiting torque of the rotating electrical machine based on the temperature of the permanent magnet estimated in the step of estimating the temperature of the permanent magnet. Method for estimating the magnet temperature of an electric machine.   The rotation according to any one of claims 8 to 10, further comprising a step of detecting an abnormality of the rotating electrical machine based on the temperature of the permanent magnet estimated in the step of estimating the temperature of the permanent magnet. Method for estimating the magnet temperature of an electric machine.   The rotation according to any one of claims 8 to 10, further comprising a step of correcting torque of the rotating electrical machine based on the temperature of the permanent magnet estimated in the step of estimating the temperature of the permanent magnet. Method for estimating the magnet temperature of an electric machine.

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