JP6299644B2 - Electric motor control device - Google Patents

Description

  The present invention relates to an electric motor control device for an electric motor using a permanent magnet.

  When a high load operation is continued in a motor having a permanent magnet, the permanent magnet is overheated due to the temperature rise of the motor. If the magnet temperature of the permanent magnet rises excessively, the magnetic force of the permanent magnet will irreversibly decrease, and even if the magnet temperature returns to room temperature, the magnetic force will not return. For this reason, when the same current flows, the torque obtained from the electric motor is reduced by the amount that the magnetic force has not been restored. In order to avoid such a situation, the permanent magnet needs to be protected from overheating due to a temperature rise of the motor.

As a method of protecting the permanent magnet from overheating, there is a method of controlling the operation by detecting the magnet temperature and relaxing the operation load or operating the cooler during heating.
Furthermore, the method for detecting the magnet temperature includes a temperature sensor or a separate sensor for detecting a magnetic flux that varies according to the magnet temperature to detect the magnet temperature, and a magnet temperature based on current and voltage during operation of the motor. Is roughly divided into those that estimate

  For estimating the conventional magnet temperature, the torque fluctuation caused by the fluctuation of the magnet temperature is calculated from the torque calculated from the detected current value of the electric motor and the torque calculated based on the electric power and the rotational speed given to the electric motor. And a technique for estimating a magnet temperature using a predetermined relationship between torque fluctuation and magnet temperature has been proposed (see, for example, Patent Document 1). In addition, a method for estimating the magnet temperature based on an electric motor model has been proposed (see, for example, Patent Document 2).

JP 2009-261182 A JP 2006-262598 A

  In the technique disclosed in Patent Document 1, the magnet temperature is estimated from the relationship between the torque fluctuation caused by the magnet temperature fluctuation and the magnet temperature. However, in the case of an electric motor in which the ratio of the magnet torque that changes according to the change in the magnet temperature and the reluctance torque that does not change according to the change in the magnet temperature is different, the relationship between the torque fluctuation and the magnet temperature depends on the individual electric motor. Different. For this reason, in order to perform accurate magnet temperature estimation, it is necessary to prepare a relationship between torque fluctuation and magnet temperature for each type of electric motor, and there is a problem that the magnet temperature cannot be estimated with a simple configuration.

  Further, in the technique disclosed in Patent Document 2, when estimating the magnet temperature based on the motor model, a map of a preset motor characteristic (for example, a map of a voltage command value with respect to a rotation speed and a torque command at a reference temperature) In addition to the magnetic flux characteristic map for the current detection value), the temperature detection means for acquiring the reference temperature is required, and thus there is a problem that the magnet temperature cannot be accurately estimated with a simple configuration.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to obtain an electric motor control device capable of estimating a magnet temperature with a simple configuration.

An electric motor control device according to the present invention is a multidimensional device in which a current command value is determined in advance corresponding to a magnet command value, which is an estimated value of a torque command value of the motor, a rotation speed of the motor, and a magnet temperature of the motor. Using a map, a current command generator that outputs the current command value;
A current control unit that outputs to the inverter circuit a voltage command value that brings a current detection value that is a detection value of a current supplied from the inverter circuit to the motor close to the current command value;
A torque estimation unit that outputs a torque estimation value based on the current command value or the current detection value, the voltage command value, and the rotation speed;
A magnet that multiplies a torque error that is a difference between the torque command value and the torque estimated value by a sign of the torque command value and a predetermined coefficient, and outputs the magnet temperature estimated value using a cumulative addition value. A temperature estimation unit.
In addition, the current command value is determined using a multi-dimensional map in which a current command value is determined in advance corresponding to a magnet temperature estimated value that is an estimated value of a torque command value of the motor, a rotational speed of the motor, and a magnet temperature of the motor. A current command generator for outputting a command value;
A current control unit that outputs to the inverter circuit a voltage command value that brings a current detection value that is a detection value of a current supplied from the inverter circuit to the motor close to the current command value;
A torque estimation unit that outputs a torque estimation value based on the current command value or the current detection value, the voltage command value, and the rotation speed;
A value obtained by accumulating a value obtained by multiplying a torque error, which is a difference between the torque command value and the estimated torque value, by a sign of the torque command value and a predetermined coefficient is added to the reference temperature of the magnet temperature. And a magnet temperature estimation unit for outputting the magnet temperature estimation value.

  In the motor control device configured as described above, the magnet temperature estimation unit calculates the magnet temperature estimation value based on the torque command value and the torque estimation value, and feeds back the magnet temperature estimation value to the current command generation unit. The magnet temperature can be estimated with a simple configuration.

It is a figure which shows the hardware constitutions of an electric motor system provided with the electric motor control apparatus which concerns on Embodiment 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side sectional view of an upper half surface of an electric motor system including an electric motor control device according to Embodiment 1 of the present invention. It is a figure which shows the structure of the inverter circuit of an electric motor system provided with the electric motor control apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the control structure of an electric motor system provided with the electric motor control apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structural example of the electric current command production | generation part in the electric motor control apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the torque estimation part in the electric motor control apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the structure of the magnet temperature estimation part in the electric motor control apparatus which concerns on Embodiment 1 of this invention. FIG. 4 is a relationship diagram between time, estimated torque value, and estimated magnet temperature in the electric motor control device according to Embodiment 1 of the present invention. FIG. 4 is a relationship diagram between time, estimated torque value, and estimated magnet temperature in the electric motor control device according to Embodiment 1 of the present invention. FIG. 4 is a relationship diagram between time, estimated torque value, and estimated magnet temperature in the electric motor control device according to Embodiment 1 of the present invention. FIG. 4 is a relationship diagram between time, estimated torque value, and estimated magnet temperature in the electric motor control device according to Embodiment 1 of the present invention. It is a figure which shows the control structure of an electric motor system provided with the electric motor control apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the example of a setting of the torque suppression part in the electric motor control apparatus which concerns on Embodiment 2 of this invention. It is a related figure of time in a motor control device concerning Embodiment 2 of this invention, a torque command value, and a magnet temperature estimated value. It is a related figure of time in a motor control device concerning Embodiment 2 of this invention, a torque command value, and a magnet temperature estimated value.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a hardware configuration of an electric motor system including an electric motor control device according to Embodiment 1 for carrying out the present invention.
In FIG. 1, the electric motor system 200 includes a host controller 102, an electric motor control device 10, an electric motor 1, a position detector 2, a current detector 3, and an inverter circuit 4.
The electric motor control device 10 includes a processor 100 and a storage device 101 as hardware.

  Although not shown, the storage device 101 includes a volatile storage device such as a random access memory and a nonvolatile auxiliary storage device such as a flash memory. Further, the storage device 101 may include an auxiliary storage device such as a hard disk instead of the nonvolatile auxiliary storage device.

The processor 100 executes a program input from the storage device 101. Since the storage device 101 includes an auxiliary storage device and a volatile storage device, a program is input to the processor 100 from the auxiliary storage device via the volatile storage device. Further, the processor 100 may output data such as a calculation result to the volatile storage device of the storage device 101, or may store the data in the auxiliary storage device via the volatile storage device.
Input / output of data and the like between the hardware components in FIG. 1 will be described later.

  FIG. 2 is a side sectional view of the upper half surface of the electric motor of the electric motor system including the electric motor control device according to the first embodiment. In FIG. 2, the electric motor 1 includes an annular stator 131 and a rotor 130 that is disposed inside the stator 131 and is rotatable with respect to the stator 131.

  The stator 131 has a stator core 132 and a winding 133 wound around the stator core 132, and the outer periphery of the stator core 132 is fixed to the frame 110. The stator core 132 is configured by laminating and integrating a plurality of magnetic steel plates formed in a predetermined shape in the central axis direction of the rotor 130. Further, the stator core 132 protrudes in a radial direction that is a direction perpendicular to the central axis of the rotor 130 from a cylindrical core back and an inner peripheral surface of the core back, and a plurality of stator cores 132 are arranged at an equiangular pitch in the circumferential direction. The teeth are provided. In FIG. 2, the teeth and the core back are omitted. The stator 131 has a winding 133 that is wound around a tooth and through which a three-phase current flows. However, the detailed winding distribution is omitted in FIG. 2.

  The rotor 130 includes a magnet 134 as a magnetomotive force generation source, a rotor core 135, and a rotation shaft 138. The rotor 130 is rotatably attached to the brackets 111 and 112 attached to both ends of the frame 110 in the central axis direction via bearings 139 attached to both ends of the rotary shaft 138 in the central axis direction. . The rotor core 135 is fixed to the outer periphery of the rotation shaft 138. Further, the rotor core 135 is disposed so as to face the stator core 132. The magnet 134 is inserted into a hole formed in the rotor core 135. A plurality of magnets 134 are arranged in the circumferential direction with respect to the rotating shaft 138 to form magnetic poles having different polarities alternately. The position detector 2 is installed on the rotary shaft 138 of the electric motor 1 and detects the angle θ of the rotor 130.

  The electric motor 1 is not limited to the rotating machine, and may be a linear machine having a mover instead of the rotor. In this case, the magnet may be provided on either the stator or the mover. The position detector 2 is installed on the mover of the electric motor 1 and detects the position of the mover in the linear motion direction as θ.

  FIG. 3 is a diagram illustrating a configuration of an inverter circuit of an electric motor system including the electric motor control device according to the present embodiment. FIG. 3 shows a specific configuration example of the inverter circuit 4 of the present embodiment. The inverter circuit 4 includes a three-phase bridge circuit 140 and a driver circuit 141. The three-phase bridge circuit 140 is supplied with DC power from a power source 152 such as a battery. As shown in FIG. 3, the three-phase bridge circuit 140 includes six switching elements 142 to 147.

  The driver circuit 141 sends a switching signal having a waveform for switching the switching elements 142 to 147 to the switching elements 142 to 147 in accordance with voltages corresponding to the three-phase voltage command values vu *, vv *, and vw *.

  Each of the three-phase bridge circuits 140 is configured by a bridge using six switching elements 142 to 147 such as MOSFETs. In the three-phase bridge circuit, switching elements 142 and 145 are connected in series, switching elements 143 and 146 are connected in series, switching elements 144 and 147 are connected in series, and these three sets of switching elements are connected in parallel. ing.

  Although not shown, shunt resistors may be connected as current detectors 3 one by one to the GND 154 (ground) side of the lower three switching elements 145, 146, and 147, respectively. These shunt resistors are used to detect a three-phase current flowing from the three-phase bridge circuit 140 to the motor 1. Although three examples of shunt resistors are shown, two shunt resistors may be used, and even with one shunt resistor, current detection is possible. Also good.

  In addition, when one shunt resistor is used as the current detector 3, the current detector 3 detects a current phase by a PLL or the like that is a phase synchronization circuit, and the three-phase current is almost balanced. The three-phase current is estimated based on the assumption that

  The three-phase current flows from between the switching element 142 and the switching element 145 to the U-phase terminal 151-1 in the winding 133 of the electric motor 1 through the bus bar or the like, and from between the switching element 143 and the switching element 146 to the U-phase terminal 151-1 through the bus bar or the like. To the V-phase terminal 151-2 in the winding 133, and to the W-phase terminal 151-3 in the winding 133 of the electric motor 1 through the bus bar or the like from between the switching element 144 and the switching element 147 and supplied to the electric motor 1. .

Moreover, you may install the current transformer etc. in these bus bars etc. one each. These current transformers and the like are used to detect a three-phase current flowing from the three-phase bridge circuit 140 to the electric motor 1. As the most preferred embodiment, FIG. 1 shows a current detector 3 composed of three current transformers and a peripheral amplifier circuit.
Two current transformers may be used. In this case, the current detector 3 obtains the remaining one-phase current value using the fact that the sum of the three-phase currents is zero.
Further, one current transformer may be used. In this case, the current detector 3 obtains a three-phase current from the assumption that the current phase detection and the three-phase current are approximately balanced in the same manner as described above.
Alternatively, from the viewpoint of cost, a shunt resistor may be connected in series with a bus bar or the like instead of the current transformer.

  FIG. 4 is a diagram illustrating a control configuration of an electric motor system including the electric motor control device according to the present embodiment. The motor controller 10 includes a current command generator 11, a current controller 13, a torque estimator 20, a magnet temperature estimator 30, a speed detector 12, a UVW / dq coordinate converter 14, and a dq / UVW. And a coordinate conversion unit 15. The motor control device 10 is based on the information of the angle θ detected by the position detector 2 installed in the motor 1 and the detected value of the three-phase current supplied from the inverter circuit 4 to the motor 1 and detected by the current detector 3. Information on certain three-phase current detection values iu, iv, and iw is acquired. Based on these pieces of information, the motor control device 10 controls the inverter circuit 4 to cause the motor 1 to output torque according to the torque command value T * input from the external host controller 102, thereby To drive. Although details will be described later, the motor control device 10 outputs a magnet temperature estimated value test, which is an estimated value of the magnet temperature of the magnet 134 included in the motor 1, to the host controller 102.

  The UVW / dq coordinate conversion unit 14 uses the well-known coordinate conversion method to detect the three-phase current detection values iu, iv, iw detected by the current detector 3 as the d-axis current detection value id and the q-axis current detection. It converts into the current detection value of the value iq.

  The current control unit 13 includes addition / subtraction units 16a and 16b and PI control units 13a and 13b. The current control unit 13 includes a d-axis current command value id * and a q-axis current command value iq * that are current command values output from the current command generation unit 11, and a d-axis current detection value id and q that are current detection values. PI control is performed so that the detected shaft current value iq matches, and a d-axis voltage command value vd * and a q-axis voltage command value vq *, which are voltage command values, are generated. That is, the current control unit 13 outputs the voltage command values vd * and vq * that bring the detected current values id and iq close to the current command values id * and iq * to the inverter circuit 4. Specifically, the adder / subtractors 16a and 16b take the deviation between the current command values id * and iq * and the detected current values id and iq, and d-axis current deviation id * -id and q, which are current deviations. A shaft current deviation iq * -iq is generated. The PI controllers 13a and 13b generate voltage command values vd * and vq * based on the current deviations id * -id and iq * -iq, respectively. Formulas (1) and (2) show calculation examples in the PI control units 13a and 13b. Here, Kpd and Kpq are respectively a d-axis proportional gain and a q-axis proportional gain, Kid and Kiq are respectively a d-axis integral gain and a q-axis integral gain, and s is a Laplace operator.

vd * = (Kpd + Kid / s) (id * −id) (1)
vq * = (Kpq + Kiq / s) (iq * −iq) (2)

  The dq / UVW coordinate conversion unit 15 converts the voltage command values vd * and vq * into the three-phase voltage command values vu * and vv * using a known coordinate conversion method based on the rotor angle θ of the electric motor 1. , Vw *.

  Then, the motor control device 10 drives the inverter circuit 4 based on the three-phase voltage command values vu *, vv *, vw *.

  The speed detector 12 detects the rotational speed ω by time-differentiating the angle θ detected by the position detector 2.

  The torque estimation unit 20 generates a torque estimation value Test based on the current detection values id and iq, the voltage command values vd * and vq *, and the rotation speed ω detected by the speed detection unit 12.

  The magnet temperature estimation unit 30 outputs a magnet temperature estimation value test based on the torque command value T * and the torque estimation value Test. The estimated magnet temperature value test is fed back to the current command generator 11 and the host controller 102.

  In addition, the current command generator 11, the current controller 13, the torque estimator 20, the magnet temperature estimator 30, the speed detector 12, the UVW / dq coordinate converter 14, and the dq / UVW coordinates in FIG. The conversion unit 15 is realized by a processor 100 that executes a program stored in the storage device 101 or a processing circuit such as a system LSI (not shown). In addition, a plurality of processors 100 and a plurality of storage devices 101 may execute the function in cooperation, or a plurality of processing circuits may execute the function in cooperation. Further, the above functions may be executed in cooperation with a combination of a plurality of processors 100 and a plurality of storage devices 101 and a plurality of processing circuits.

  FIG. 5 is a diagram illustrating a configuration example of a current command generation unit in the motor control device according to the present embodiment. The current command generator 11 corresponds to the torque command value T *, the rotational speed ω, and the magnet temperature estimated value test that is an estimated value of the magnet temperature of the magnet 134 of the electric motor 1 estimated by the magnet temperature estimating unit 30 described later. Then, the current command values id * and iq * are output using a multi-dimensional map in which the current command values id * and iq * are predetermined. As shown in FIG. 5, the current command value id * corresponding to the torque command value T * and the rotational speed ω at a plurality of magnet temperatures (in the example of FIG. 5, when test = −40 ° C., 20 ° C., 80 ° C.). And a multi-dimensional map of iq * is preset. In these multi-dimensional maps, a q-axis current command value iq * that increases as the temperature rises is set so that torque is output according to the torque command value T * even if demagnetization of the magnet occurs.

  FIG. 6 is a diagram illustrating a configuration of a torque estimation unit in the motor control device according to the present embodiment. The torque estimation unit 20 includes an input power calculation unit 21, a loss calculation unit 22, an addition / subtraction unit 23, and a multiplication / division unit 24.

  The input power calculation unit 21 calculates the input power Pac input to the electric motor 1 based on the inner product of the current detection values id and iq and the voltage command values vd * and vq *.

  The loss calculator 22 calculates the loss Ploss in the electric motor 1 based on the current detection values id and iq and the rotation speed ω. For example, the copper loss is calculated based on the current detection values id and iq. The iron loss is calculated based on the current detection values id and iq and the rotation speed ω. The mechanical loss is calculated based on the rotational speed ω.

  Although not shown in FIGS. 4 and 6, by adding a torque command T * to the inputs of the torque estimation unit 20 and the loss calculation unit 22, the loss calculation unit 22 can obtain the torque command value T * and the rotation speed. The loss Ploss may be calculated using a map of losses (for example, the sum of iron loss and mechanical loss) other than copper loss determined in advance corresponding to ω. Moreover, although the torque estimation part 20 in FIG.4 and FIG.6 is calculating with the electric current detection value id and iq as an input, you may calculate it with electric current command value id * and iq * as an input.

The adder / subtracter 23 subtracts the loss Ploss calculated by the loss calculator 22 from the input power Pac calculated by the input power calculator 21.
The multiplier / divider 24 divides the result output from the addition / subtractor 23 by the rotational speed ω.
As a result, the estimated torque value Test is calculated as in Expression (3) based on the input power Pac calculated by the input power calculation unit 21, the loss Ploss calculated by the loss calculation unit 22, and the rotation speed ω. The

    Test = (Pac−Ploss) / ω (3)

  FIG. 7 is a diagram illustrating a configuration of a magnet temperature estimation unit in the motor control device according to the present embodiment. The magnet temperature estimation unit 30 includes a sign setting unit 31, an integrator 32, a reference temperature setting unit 33, a low-pass filter 34, a time constant setting unit 35, an addition subtracter 36a, and an adder 36b.

  The sign setting unit 31 determines that the torque command value T * is positive based on the torque error value Terr obtained by subtracting the estimated torque value Test from the torque command value T * by the adder / subtractor 36a and the torque command value T *. Outputs the torque error Terr without changing the sign, and when the torque command value T * is negative, outputs the torque error -Terr with the sign reversed. That is, the sign setting unit 31 outputs a value obtained by multiplying the torque error Terr, which is the difference between the torque command value T * and the estimated torque value Test, by the sign of the torque command value T *.

  The integrator 32 multiplies a predetermined proportionality coefficient KI by a value obtained by multiplying the torque error Terr output from the sign setting unit 31 by the sign of the torque command value T *, and cumulatively adds the result by time integration. .

  The adder 36b outputs a magnet temperature calculation value obtained by adding the reference temperature tinit of the magnet temperature, which is a value set by the reference temperature setting unit 33, to the result of the cumulative addition by the integrator 32. The ambient temperature around the motor 1 is set in advance as the magnet temperature reference temperature tinit.

  Finally, the low-pass filter 34 applies the filter that outputs the waveform of the time constant set by the time constant setting unit 35 to the calculated magnet temperature value output by the adder 36b, and outputs the estimated magnet temperature value test. At this time, the time constant of the low-pass filter 34 is variably set by the time constant setting unit 35.

Although not shown in FIGS. 4 and 7, the rotational speed ω is added to the inputs of the magnet temperature estimation unit 30 and the time constant setting unit 35, and the time constant setting unit 35 rotates the time constant of the low-pass filter 34. It may be variably set corresponding to the speed ω. For example, by reducing the time constant during low-speed rotation where the estimated torque value Test is stably output, and by setting the time constant large during high-speed rotation where the estimated torque value Test is likely to pulsate, the fastest response at each rotational speed is achieved. The magnet temperature can be estimated.
In addition, the time constant setting unit 35 may set the time constant of the low-pass filter 34 using a time constant map of the low-pass filter 34 determined in advance corresponding to the rotation speed ω.

The operation of the motor control apparatus configured as described above will be described.
FIG. 8 is a relationship diagram of time, estimated torque value, and estimated magnet temperature in the motor control device according to the present embodiment. The horizontal axis of FIG. 8 represents time, and the vertical axis of FIG. 8 represents the estimated torque value Test on the upper stage and the estimated magnet temperature test on the lower stage, respectively. FIG. 8 shows an operation example of the estimated torque value Test and the estimated magnet temperature test when the positive torque command value T * is step-input in a state where the magnet temperature is increased by Δt from the reference temperature tinit. ing.

  In the upper part of FIG. 8, immediately after the step input of the torque command value T *, the estimated torque value Test becomes smaller than the torque command value T * by the torque error ΔT due to the magnet temperature fluctuation amount Δt. In the magnet temperature estimation unit 30, a value obtained by multiplying the positive torque error Terr by the positive sign of the torque command value T * is cumulatively added by the integrator 32. In the adder 36b, the reference temperature tinit is added to the cumulative addition result, and the magnet temperature estimated value test is output. As a result, the magnet temperature estimated value test increases with time. Then, in the current command generation unit 11 to which the estimated magnet temperature test is fed back, current command values id * and iq * corresponding to the magnet temperature at a high temperature are generated, so that the torque command value T * is added to the torque error Terr. The magnitude of the value multiplied by the sign gradually decreases. When the torque command value T * and the torque estimated value Test match, the magnet temperature estimated value test matches the current magnet temperature tnow as shown in the lower part of FIG.

  FIG. 9 is a relationship diagram of time, estimated torque value, and estimated magnet temperature in the electric motor control device according to the present embodiment. The horizontal axis of FIG. 9 represents time, and the vertical axis of FIG. 9 represents the estimated torque value Test on the upper stage and the estimated magnet temperature test on the lower stage, respectively. As in FIG. 8, FIG. 9 shows a torque estimated value Test and a magnet temperature estimated value test when a negative torque command value T * is step-inputted in a state where the magnet temperature is increased by Δt from the reference temperature tinit. An example of the operation is shown.

  In the upper part of FIG. 9, the sign of the torque error Terr due to the fluctuation of the magnet temperature is reversed from that in the upper part of FIG. For this reason, the sign setting unit 31 of the magnet temperature estimation 30 inverts the sign of the torque error Terr. With this operation, in the lower part of FIG. 9, as in the lower part of FIG. 8, the value obtained by multiplying the negative torque error Terr by the sign of the torque command value T * is cumulatively added by the integrator 32 in the magnet temperature estimation unit 30. Is done. In the adder 36b, the reference temperature tinit is added to the cumulative addition result, and the magnet temperature estimated value test is output. As a result, the magnet temperature estimated value test increases with time. 9, since the estimated magnet temperature test is fed back to the current command generator 11 as in the upper case of FIG. 8, the torque error Terr is multiplied by the sign of the torque command value T *. Gradually decreases, and the torque command value T * matches the estimated torque value Test. At this time, as shown in the lower part of FIG. 9, the magnet temperature estimated value test matches the current magnet temperature tnow. For this reason, magnet temperature estimation and torque fluctuation suppression are possible.

  Therefore, the motor control apparatus 10 according to the present embodiment is a multidimensional map in which the current command values id * and iq * are determined in advance corresponding to the torque command value T *, the rotation speed ω, and the magnet temperature estimated value test. , A current command generation unit 11 that outputs current command values id * and iq *, a current control unit 13 that outputs voltage command values vd * and vq * to the inverter circuit 4, and current command values id * and iq * Or a torque estimation unit 20 that outputs a torque estimated value Test based on the current detection values id and iq, the voltage command values vd * and vq *, and the rotational speed ω; and the torque command value T * and the torque estimated value Test A magnet temperature estimator 3 for outputting a magnet temperature estimated value test by accumulatively adding a value obtained by multiplying the torque error Terr as a difference by the sign of the torque command value T *. 0.

  With this configuration, the magnet temperature estimation unit 30 calculates the magnet temperature estimation value test based on the torque command value T * and the torque estimation value Test, and feeds back the magnet temperature estimation value test to the current command generation unit 11. The magnet temperature can be estimated with a simple configuration. Further, torque fluctuations caused by fluctuations in magnet temperature can be suppressed.

  Further, the magnet temperature estimation unit 30 in the electric motor control device 10 according to the present embodiment adds a value obtained by accumulating a value obtained by multiplying the torque error Terr by the sign of the torque command value T * to the reference temperature tinit of the magnet temperature. The magnet temperature estimated value test is output by adding.

  With this configuration, in addition to the same effects as described above, the current magnet temperature tnow can be estimated with a simple configuration.

  Further, the magnet temperature estimation unit 30 in the electric motor control device 10 according to the present embodiment includes a value obtained by cumulatively adding a value obtained by multiplying the sign of the torque command value T * by the torque error Terr, and a predetermined time constant. The time constant is set using a time constant map in which the time constant is determined in advance corresponding to the rotational speed ω.

  With this configuration, in addition to the same effects as described above, the magnet temperature can be estimated with the fastest response at each rotation speed.

  In the multi-dimensional map of the current command generation unit 11, the current command values id * and iq * that maximize the efficiency are set in advance for a plurality of magnet temperatures assumed in actual operation, so that torque fluctuations are achieved. The electric motor 1 can be driven with the maximum efficiency while suppressing the above.

Another example of operation of the motor control device 10 will be described.
FIG. 10 is a relationship diagram of time, estimated torque value, and estimated magnet temperature in the electric motor control apparatus according to the present embodiment. The horizontal axis in FIG. 10 represents time, and the vertical axis in FIG. 10 represents the estimated torque value Test on the upper stage and the estimated magnet temperature test on the lower stage. FIG. 10 shows an operation example of the estimated torque value Test and the estimated magnet temperature value when the positive torque command value T * is changed to zero in a state where the magnet temperature is increased by Δt from the reference temperature tinit. ing.

  In the upper part of FIG. 10, when the torque command value T * is zero, torque fluctuation due to fluctuation of the magnet temperature does not occur, so the magnet temperature cannot be estimated. Therefore, in the operation example of FIG. 10, when the absolute value of the torque command value T * is smaller than a predetermined value (for example, 1% of the rated torque of the electric motor 1), the integrator 32 in the magnet temperature estimation unit 30. Is held at tnow which is the value of the magnet temperature estimated value test immediately before the torque command value T * becomes zero. As a result, the magnet temperature estimated value test is maintained at a value immediately before the torque command value T * becomes zero. For example, for the electric motor 1 having a large time constant of the magnet temperature, even when the torque command value T * is set to zero, the decrease amount of the magnet temperature is small. Therefore, the magnet temperature estimated value test may be the magnet temperature tnow that is the magnet temperature estimated value test immediately before the torque command value T * becomes equal to or less than a predetermined value.

  Therefore, magnet temperature estimating unit 30 in electric motor control device 10 according to the present embodiment is predetermined as magnet temperature estimated value test when the magnitude of torque command value T * is equal to or smaller than a predetermined value. When the torque command value T * is larger than a predetermined value, the magnet temperature is obtained by cumulatively adding a value obtained by multiplying the torque error Terr by the sign of the torque command value T *. The estimated value test is output.

  With this configuration, in addition to the same effects as described above, it is possible to estimate an appropriate magnet temperature even in a state where torque fluctuations due to fluctuations in magnet temperature do not occur.

  Further, in the motor control device 10 according to the present embodiment, when the magnitude of the torque command value T * is equal to or smaller than a predetermined value, the predetermined temperature output as the magnet temperature estimated value test is the torque This is a magnet temperature estimated value test immediately before the command value T * becomes equal to or less than a predetermined value.

  With this configuration, in addition to the same effects as described above, the estimated magnet temperature value test can be maintained at a value immediately before the torque command value T * becomes zero, and torque fluctuations due to fluctuations in magnet temperature occur. An appropriate magnet temperature can be estimated even in a state in which it is not.

  FIG. 11 is a relationship diagram of time, estimated torque value, and estimated magnet temperature in the electric motor control apparatus according to the present embodiment. The horizontal axis in FIG. 11 represents time, and the vertical axis in FIG. 11 represents the estimated torque value Test on the upper stage and the estimated magnet temperature test on the lower stage, respectively. FIG. 11 shows the estimated torque value Test and the magnet temperature when the positive torque command value T * is changed to zero in a state where the magnet temperature is increased by Δt from the reference temperature tinit and the magnet temperature is the same as the lower part of FIG. An operation example with the estimated value test is shown.

  In the upper part of FIG. 11, when the magnitude of the torque command value T * is smaller than a predetermined value (for example, 1% of the rated torque of the electric motor 1), the integrator 32 in the magnet temperature estimation unit 30 outputs Resets the value and outputs a zero value. The adder 36 b in the magnet temperature estimation unit 30 outputs a calculated magnet temperature value obtained by adding the reference temperature tinit to the zero output value of the integrator 32 to the low-pass filter 34. As a result, the magnet temperature estimated value test, which is the output of the low-pass filter 34, smoothly decreases toward the reference temperature tinit according to the time constant of the low-pass filter 34. For example, the time constant of the low-pass filter 34 is set based on the time constant of the magnet temperature of the electric motor 1.

  Therefore, in the electric motor control device 10 according to the present embodiment, the predetermined temperature is the reference temperature tinit of the magnet temperature.

  With this configuration, in addition to the same effects as described above, even in the case of the electric motor 1 having a small magnet temperature time constant, even in a state where torque fluctuation due to fluctuation of the magnet temperature does not occur due to this operation, the torque command value It is possible to estimate the magnet temperature when T * is set to a predetermined value or less.

  Further, the magnet temperature estimation unit 30 in the electric motor control device 10 according to the present embodiment includes a value obtained by cumulatively adding a value obtained by multiplying the sign of the torque command value T * by the torque error Terr, and a predetermined time constant. And a low-pass filter 34 that outputs a magnet temperature estimated value test based on the time constant, and the time constant is set based on the time constant of the magnet temperature.

  With this configuration, in addition to the same effect as described above, unlike the lower case of FIG. 10, in the case of the electric motor 1 with a small time constant of the magnet temperature, the torque fluctuation caused by the fluctuation of the magnet temperature due to this operation Even in a state where no occurrence occurs, an appropriate magnet temperature can be estimated.

The time constant of the low-pass filter 34 may be set equal to the time constant of the magnet temperature of the electric motor 1.
Thereby, since the magnet temperature can be estimated with the same attenuation curve as the time constant of the magnet temperature of the electric motor 1, the estimation accuracy of the magnet temperature in the transient state can be improved.

Embodiment 2. FIG.
FIG. 12 is a diagram showing a control configuration of an electric motor system including an electric motor control device according to Embodiment 2 for carrying out the present invention. Electric motor control device 10 according to the present embodiment is an embodiment in that it further includes a protection function unit 40 that receives torque command value T0 * before suppression and magnet temperature estimated value test as input, and outputs torque command value T *. Different from 1. The protection function unit 40 includes a torque suppression unit 41 and an abnormality determination unit 42.

When the estimated magnet temperature value test exceeds a predetermined value with respect to the torque command T0 * before suppression given from the external host controller 102, the torque suppression unit 41 sets the torque command value T0 *. A torque command value T * smaller than the absolute value is output to the current command generator 11. Here, the torque command value T * is multiplied by a predetermined torque limit gain that decreases the absolute value of the torque command value T0 * before suppression in accordance with the absolute value of the magnet temperature estimated value test. Is calculated. That is, the torque suppression unit 41 makes the magnitude of the torque command value T * smaller than the magnitude of the torque command T0 * before suppression based on the magnet temperature estimated value test.
The abnormality determination unit 42 detects an abnormality of the electric motor 1 based on the magnet temperature estimated value test.

  FIG. 13 is a diagram illustrating a setting example of the torque suppression unit in the electric motor control device according to the present embodiment. The horizontal axis in FIG. 13 represents the magnet temperature, and the vertical axis in FIG. 13 represents the torque limit gain. In FIG. 13, a torque limit gain of 0.0 to 1.0 is set corresponding to the magnet temperature. As shown in FIG. 13, when the magnet temperature is equal to or lower than a predetermined limit value limit, the torque suppression unit 41 outputs the same value as the torque command T0 * before suppression as the torque command value T *. When the magnet temperature exceeds a predetermined limit value tlimit, the torque suppression unit 41 multiplies the torque command value T0 * before suppression by a torque command value T * before the torque command value T *. Output as. For this reason, when the magnet temperature exceeds the limit value tlimit, the torque command value T * is suppressed and becomes smaller. When the magnet temperature exceeds a predetermined maximum value tmax, the torque command value T * becomes zero because the torque limit gain becomes zero. The limit value tlimit and the maximum value tmax of the magnet temperature may be set as tmax = tlimit + 20 [° C.], where the temperature range in which the torque is limited is 20 ° C.

The operation of the motor control apparatus configured as described above will be described.
FIG. 14 is a relationship diagram of time, torque command value, and magnet temperature estimated value in the motor control device according to the present embodiment. The horizontal axis of FIG. 14 represents time, and the vertical axis of FIG. 14 represents the torque command value T * in the upper stage and the estimated magnet temperature value test in the lower stage, respectively. FIG. 14 shows an operation example of the torque command value T * and the magnet temperature estimated value test when the constant torque command value T * is continuously applied from the state of the reference temperature tinit.

  In the lower part of FIG. 14, since the motor 1 generates heat when the motor 1 is energized, the magnet temperature estimated value test continues to increase. When the estimated magnet temperature value test exceeds a predetermined limit value limit, the torque suppression unit 41 operates to limit the torque command value T * as shown in the upper part of FIG. In the lower part of FIG. 14, since the torque command value T * is limited, the increase in the magnet temperature estimated value test is stopped, and the magnet temperature estimated value test decreases so as to converge to a predetermined limit value tlimit.

  Therefore, the electric motor control device 10 according to the present embodiment further includes a torque suppression unit 41 that reduces the magnitude of the torque command value T * based on the magnet temperature estimated value test.

  With this configuration, in addition to the same effects as in the first embodiment, excessive heat generation of the electric motor 1 can be prevented and the operation of the electric motor 1 can be continued.

  In addition, in order to implement | achieve the operation | movement of FIG. 14, the protection function part 40 in FIG. 12 should just have the torque suppression part 41. FIG. Even if the protection function unit 40 does not have the abnormality determination unit 42, the operation of FIG. 14 can be realized and the above-described effects can be achieved.

FIG. 15 is a relationship diagram of time, torque command value, and magnet temperature estimated value in the motor control device according to the present embodiment. The horizontal axis in FIG. 15 represents time, and the vertical axis in FIG. 15 represents the torque command value T * in the upper stage and the estimated magnet temperature value test in the lower stage, respectively. FIG. 15 shows an operation example of the torque command value T * and the magnet temperature estimated value test when a constant torque command value T * is continuously applied from the state of the reference temperature tinit, as in FIG. 15 is different from FIG. 14 in that even if the torque command value T * is limited by the operation of the torque suppressing unit 41, the increase in the magnet temperature estimated value test is not settled.
In the lower part of FIG. 15, when the estimated magnet temperature value test exceeds a predetermined warning temperature twarn, the abnormality determination unit 42 outputs an abnormality signal indicating an abnormality of the electric motor 1 to an upper controller 102 (not shown). . The host controller 102 receives the abnormal signal and cuts off the power supply from the DC power source to the inverter circuit 4. As a result, since the electric motor 1 is stopped, an increase in the magnet temperature estimated value test is suppressed.

  The abnormality determination unit 42 may output an abnormality signal to the current command generation unit 11. As will be described later, the current command generator 11 may output current command values id * and iq * for stopping energization of the electric motor 1 to the current controller 13 in response to an abnormal signal.

  In addition, the abnormality determination unit 42 may output a stop signal for stopping energization of the electric motor 1 to the current command generation unit 11. In this case, the current command generation unit 11 receives the stop signal and outputs current command values id * and iq * for stopping the electric motor 1 after decelerating to the current control unit 13. The current control unit 13 outputs voltage command values vd * and vq * for stopping the electric motor 1 after decelerating to the dq / UVW coordinate conversion unit 15. The dq / UVW coordinate conversion unit 15 converts the motor 1 into a three-phase voltage command value vu *, vv *, vw * that stops the motor 1 after decelerating and outputs it to the inverter circuit 4. The inverter circuit 4 outputs a three-phase current to the electric motor 1 to stop the electric motor 1 after decelerating. As a result, since the electric motor 1 is stopped, an increase in the magnet temperature estimated value test is suppressed.

  The current command generation unit 11 may output a current command value id * and iq * of 0 to the current control unit 13 in response to a stop signal for stopping energization of the electric motor 1. In this case, the current control unit 13 outputs voltage command values vd * and vq * of 0 to the dq / UVW coordinate conversion unit 15. The dq / UVW coordinate conversion unit 15 converts the three-phase voltage command values vu *, vv *, and vw * to 0 and outputs them to the inverter circuit 4. The inverter circuit 4 outputs a three-phase current of 0 to the electric motor 1 and stops energization of the electric motor 1. As a result, energization of the electric motor 1 is stopped earlier than when the electric motor 1 is stopped after being decelerated, so that an increase in the magnet temperature estimated value test is suppressed earlier.

  Therefore, the electric motor control device 10 according to the present embodiment further includes an abnormality determination unit 42 that determines an abnormality of the electric motor 1 based on the magnet temperature estimated value test, and the abnormality determination unit 42 has the magnet temperature estimated value test When the temperature is higher than a predetermined warning temperature twarn, an abnormality signal indicating an abnormality of the electric motor 1 is output, or energization of the electric motor 1 is stopped.

  With this configuration, in addition to the same effects as in the first embodiment, even if the torque command value T * is limited and the increase in the magnet temperature estimated value test does not stop, the motor 1 may be damaged due to excessive heat generation. The irreversible demagnetization of the magnet 134 can be prevented and the electric motor 1 can be protected.

  DESCRIPTION OF SYMBOLS 1 Electric motor, 2 Position detector, 3 Current detector, 4 Inverter circuit, 10 Electric motor control apparatus, 11 Current command production | generation part, 12 Speed detection part, 13 Current control part, 14 UVW / dq coordinate conversion part, 15 dq / UVW Coordinate conversion unit, 16a, 16b, 23, 36a Addition / subtraction unit, 20 Torque estimation unit, 21 Input power calculation unit, 22 Loss calculation unit, 24 Multiplying divider, 30 Magnet temperature estimation unit, 31 Sign setting unit, 32 Integrator , 33 Reference temperature setting unit, 34 Low-pass filter, 35 Time constant setting unit, 36b Adder, 40 Protection function unit, 41 Torque suppression unit, 42 Abnormality determination unit, 100 processor, 101 storage device, 102 upper controller, 110 frame 111, 112 Bracket, 130 Rotor, 131 Stator, 132 Stator core, 133 Wire, 134 Magnet, 135 Rotor core, 138 Rotating shaft, 139 Bearing, 140 Three-phase bridge circuit, 141 Driver circuit, 142-147 Switching element, 151-1 U-phase terminal, 151-2 V-phase terminal, 151-3 W-phase terminal, 152 power supply, 154 GND, 200 electric motor system.

Claims (10)

The current command value is determined using a multi-dimensional map in which a current command value is predetermined corresponding to an estimated value of a torque command value of the motor, a rotational speed of the motor, and a magnet temperature estimated value of the magnet temperature of the motor. A current command generator that outputs
A current control unit that outputs to the inverter circuit a voltage command value that brings a current detection value that is a detection value of a current supplied from the inverter circuit to the motor close to the current command value;
A torque estimation unit that outputs a torque estimation value based on the current command value or the current detection value, the voltage command value, and the rotation speed;
A magnet that multiplies a torque error that is a difference between the torque command value and the torque estimated value by a sign of the torque command value and a predetermined coefficient, and outputs the magnet temperature estimated value using a cumulative addition value. An electric motor control device comprising a temperature estimation unit.   The magnet temperature estimation unit feeds back the magnet temperature estimation value to the current command generation unit, and the current command generation unit generates the current command value using the magnet temperature estimation value and the multidimensional map. The electric motor control device according to claim 1. The current command value is determined using a multi-dimensional map in which a current command value is predetermined corresponding to an estimated value of a torque command value of the motor, a rotational speed of the motor, and a magnet temperature estimated value of the magnet temperature of the motor. A current command generator that outputs
A current control unit that outputs to the inverter circuit a voltage command value that brings a current detection value that is a detection value of a current supplied from the inverter circuit to the motor close to the current command value;
A torque estimation unit that outputs a torque estimation value based on the current command value or the current detection value, the voltage command value, and the rotation speed;
Adding a value calculated by multiplying the sign with a predetermined coefficient of the torque command value to the torque error which is the difference is cumulatively added with the estimated torque value and the torque command value based on quasi temperature of the magnet temperature motor control device and a magnet temperature estimating unit which outputs the magnet temperature estimate by. When the magnitude of the torque command value is equal to or less than a predetermined value, the magnet temperature estimation unit outputs a temperature predetermined as the magnet temperature estimation value,
According the magnitude of the torque command value when the larger predetermined value by cumulatively adding the value obtained by multiplying the sign of the torque command value to the torque error, outputting said magnet temperature estimate The electric motor control device according to any one of claims 1 to 3 . The motor control device according to claim 4 , wherein the predetermined temperature is the magnet temperature estimated value immediately before the torque command value becomes equal to or less than the predetermined value. The motor control device according to claim 5 , wherein the predetermined temperature is a reference temperature of the magnet temperature. The magnet temperature estimation unit outputs a magnet temperature estimation value based on a value obtained by accumulating a value obtained by multiplying the torque error by the sign of the torque command value and a predetermined time constant. Have
The motor control device according to claim 6 , wherein the time constant is set based on a time constant of the magnet temperature. The magnet temperature estimation unit outputs a magnet temperature estimation value based on a value obtained by accumulating a value obtained by multiplying the torque error by the sign of the torque command value and a predetermined time constant. Have
The motor control device according to any one of claims 1 to 7 , wherein the time constant is set using a time constant map in which the time constant is determined in advance corresponding to the rotation speed. The motor control device according to any one of claims 1 to 8 , further comprising a torque suppression unit that reduces the magnitude of the torque command value based on the estimated magnet temperature value. An abnormality determination unit that determines abnormality of the electric motor based on the estimated magnet temperature value,
The motor control device according to claim 9 , wherein the abnormality determination unit outputs an abnormality of the electric motor or stops energization of the electric motor when the estimated magnet temperature value is higher than a predetermined warning temperature. .

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