Power Conversion Equipment

Abstract

To estimate a magnet temperature by using an estimation technology based on a voltage disturbance observer, in a power conversion device.SOLUTION: A current control unit 2 outputs a d-axis voltage command value vd* and a q-axis voltage command value vq* on the basis of a d-axis current command value id*, a q-axis current command value iq*, a d-axis current detection value Id, and a q-axis current detection value iq. A two-phase-to-three-phase converter 3 performs two-phase-to-three-phase conversion of the d-axis voltage command value vd* and the q-axis voltage command value vq*, and outputs a three-phase voltage command value. A rotational position sensor 10 detects a phase θ of a motor 8. A three-phase-to-two-phase converter 5 converts a three-phase current detection value iuvw outputted from an inverter 7 into the d-axis current detection value Id and the q-axis current detection value iq. An angular velocity output part 6 outputs a mechanical angle angular velocity ω on the basis of the phase θ. A temperature estimation unit 4 calculates a temperature estimation value T^ of the motor 8 on the basis of the d-axis voltage command value vd*, the q-axis voltage command value vq*, the mechanical angle angular velocity ω, the d-axis current detection value Id, and the q-axis current detection value iq.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to magnet temperature estimation of a synchronous motor driven by a power conversion device, and to a technique for estimating the magnet temperature without providing a temperature sensor. [Background technology]

[0002] Non-Patent Document 1 and Patent Document 1 disclose a technique for estimating magnet temperature by estimating magnet flux linkage with an observer in an IPMSM (interior permanent magnet synchronous motor). Non-Patent Document 2 discloses stator temperature estimation using a voltage disturbance observer in an SPMSM (surface permanent magnet synchronous motor). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-16226 [Non-patent literature]

[0004] [Non-Patent Document 1] Takashi Kato, Kensuke Sasaki, Diego Fernandez Laborda, Daniel Fernandez Alonso, David Diaz Reigosa, "Magnet Temperature Estimation Method for Variable Leakage Flux IPMSM Using Magnet Flux Linkage Observer", IEEJ Transactions on Industrial Applications, Vol. 140, No. 4 (2020), pp. 265-271. [Non-Patent Document 2] Hiroki Iwata, Kiyoshi Ohishi, Yuki Yokokura, Yuji Okada, Yuji Ide, Daigo Kuraishi, Akihiko Takahashi, "Robust Estimation Method for Stator Temperature Based on Voltage Disturbance Observer Autotuning Resistance for SPMSM", IEEJ Journal of Industry Applications Vol.9, No.4(2020), pp.341-350. Summary of the Invention [Problem to be solved by the invention]

[0005] However, the methods of Non-Patent Document 1 and Patent Document 1 require the application of harmonic superimposed current, so a new current command must be generated. The method of Non-Patent Document 2 has many system layers, so there are problems such as many adjustment parameters and it is difficult to increase the bandwidth.

[0006] In view of the above, a challenge for a power conversion device is to estimate the magnet temperature by using an estimation technique based on a voltage disturbance observer. [Means for solving the problem]

[0007] The present invention has been devised in view of the above-mentioned problems in the related art, and one aspect of the present invention is characterized by comprising: a current controller that outputs a d-axis voltage command value and a q-axis voltage command value based on a d-axis current command value, a q-axis current command value, a d-axis current detection value, and a q-axis current detection value; a two-phase to three-phase converter that performs two-phase to three-phase conversion on the d-axis voltage command value and the q-axis voltage command value and outputs a three-phase voltage command value; an inverter that outputs a voltage to a motor based on the three-phase voltage command value; a motor rotational position sensor that detects the phase of the motor; a three-phase to two-phase converter that converts the three-phase current detection values ​​of the inverter output into the d-axis current detection value and the q-axis current detection value;

[0008] In one aspect, the temperature estimator includes a voltage disturbance observer that calculates a q-axis voltage disturbance estimated value based on the q-axis voltage command value and the q-axis current detection value, a pole pair number multiplication unit that calculates an electrical angle velocity by multiplying the mechanical angle velocity by a pole pair number, and a temperature calculator that calculates the temperature estimated value based on the q-axis voltage disturbance estimated value, the d-axis current detection value, the q-axis current detection value, and the electrical angle velocity.

[0009] In one aspect, the voltage disturbance observer calculates the q-axis voltage disturbance estimated value by the following equation (2).

[0010]

number

[0011] v^ q vdob : q-axis voltage disturbance estimate s: Laplace operator g dis : Cutoff frequency of the voltage disturbance observer v q * : q-axis voltage command value Lqn : Nominal value of q-axis inductance R an :Nominal resistance value i q : q-axis current detection value.

[0012] In another aspect, the motor control system includes a current controller that outputs a d-axis voltage command value and a q-axis voltage command value based on a d-axis current command value, a q-axis current command value, a d-axis current detection value, and a q-axis current detection value, a two-phase to three-phase converter that performs two-phase to three-phase conversion on the d-axis voltage command value and the q-axis voltage command value and outputs a three-phase voltage command value, an inverter that outputs a voltage to a motor based on the three-phase voltage command value, a motor rotational position sensor that detects the phase of the motor, a three-phase to two-phase converter that converts the three-phase current detection values ​​of the inverter output to the d-axis current detection value and the q-axis current detection value, an angular velocity output unit that outputs a mechanical angular velocity based on the phase, and a temperature estimator that calculates a stator temperature estimate and a magnet temperature estimate of the motor based on the d-axis voltage command value, the q-axis voltage command value, the mechanical angular velocity, the d-axis current detection value, and the q-axis current detection value.

[0013] In one aspect, the temperature estimator includes a voltage disturbance observer that calculates a d-axis voltage disturbance estimated value and a q-axis voltage disturbance estimated value based on the d-axis voltage command value, the q-axis voltage command value, the d-axis current detection value, and the q-axis current detection value; a pole pair number multiplication unit that calculates an electrical angle angular velocity by multiplying the mechanical angle angular velocity by a pole pair number; a resistance / flux estimator that calculates a nominal error estimate of resistance and a magnetic flux estimate based on the d-axis voltage disturbance estimated value, the q-axis voltage disturbance estimated value, the d-axis current detection value, the q-axis current detection value, and the electrical angle angular velocity; and a temperature calculator that calculates the stator temperature estimate and the magnet temperature estimate based on the nominal error estimate of resistance and the magnetic flux estimate.

[0014] In one aspect, the voltage disturbance observer calculates the d-axis voltage disturbance estimated value and the q-axis voltage disturbance estimated value by the following equations (2) and (8).

[0015]

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[0016]

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[0017] v^ q vdob : q-axis voltage disturbance estimate v^ d vdob : d-axis voltage disturbance estimate s: Laplace operator g dis : Cutoff frequency of the voltage disturbance observer v g * : q-axis voltage command value v d * : d-axis voltage command value L qn : Nominal value of q-axis inductance L dn : Nominal value of d-axis inductance R an :Nominal resistance value i q : q-axis current detection value i d : d-axis current detection value.

[0018] In one aspect, the resistance / flux estimator calculates the nominal error estimate of the resistance and the magnetic flux estimate by equations (9) and (10).

[0019]

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[0020]

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[0021] ΔR^ a : Nominal error estimate of resistance v^ d vdob : d-axis voltage disturbance estimate L q :q-axis inductance i q : q-axis current detection value ω e : Electrical angle Angular velocity i d : d-axis current detection value Φ^: Estimated magnetic flux v^ qvdob : q-axis voltage disturbance estimate L d : d-axis inductance.

[0022] In one aspect, the temperature estimator calculates the stator temperature estimated value and the magnet temperature estimated value by equations (11) and (12).

[0023]

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[0024]

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[0025] T^ st : Estimated stator temperature ΔR^ a : Nominal error estimate of resistance R n : Resistance at reference temperature α: Temperature coefficient of resistance T^ pm : Estimated magnet temperature Φ^: Estimated magnetic flux Φ n : Magnetic flux at reference temperature β: Temperature coefficient of magnetic flux.

[0026] As another aspect, there is provided a current controller that outputs a d-axis voltage command value and a q-axis voltage command value based on a d-axis current command value, a q-axis current command value, a d-axis current detection value, and a q-axis current detection value, a two-phase to three-phase converter that performs two-phase to three-phase conversion on the d-axis voltage command value and the q-axis voltage command value and outputs a three-phase voltage command value, an inverter that outputs a voltage to a motor based on the three-phase voltage command value, a motor rotational position sensor that detects the phase of the motor, a three-phase to two-phase converter that converts the three-phase current detection values ​​of the inverter output into the d-axis current detection value and the q-axis current detection value, an angular velocity output unit that outputs a mechanical angle angular velocity based on the phase, a temperature estimator that calculates a temperature estimate value, a stator temperature estimate value, and a magnet temperature estimate value of the motor based on the d-axis voltage command value, the q-axis voltage command value, the mechanical angle angular velocity, the d-axis current detection value, and the q-axis current detection value, and and an estimation selector that selects which of the stator temperature estimated value and the magnet temperature estimated value to display, wherein the temperature estimator comprises: a voltage disturbance observer that calculates a d-axis voltage disturbance estimated value and a q-axis voltage disturbance estimated value based on the d-axis voltage command value, the q-axis voltage command value, the d-axis current detection value, and the q-axis current detection value; a pole pair number multiplication unit that calculates the electrical angle angular velocity by multiplying the mechanical angle angular velocity by a pole pair number; a resistance / flux estimator that calculates a nominal error estimate of resistance and a magnetic flux estimate based on the d-axis voltage disturbance estimated value, the q-axis voltage disturbance estimated value, the d-axis current detection value, the q-axis current detection value, and the electrical angle angular velocity; and a temperature calculator that calculates the temperature estimate based on the q-axis voltage disturbance estimated value, the d-axis current detection value, the q-axis current detection value, and the electrical angle angular velocity, and calculates the stator temperature estimated value and the magnet temperature estimated value based on the nominal error estimate of resistance and the magnetic flux estimate.

[0027] In one aspect, the estimation selector displays the stator temperature estimated value and the magnet temperature estimated value when the d-axis current detection value is not 0 and the electrical angle angular velocity is not 0, displays the stator temperature estimated value when the d-axis current detection value is not 0 and the electrical angle angular velocity is 0, displays the temperature estimated value when the d-axis current detection value is 0 and at least one of the electrical angle angular velocity and the q-axis current detection value is not 0, and does not display any of the temperature estimated value, the stator temperature estimated value, or the magnet temperature estimated value when the d-axis current detection value is 0, the electrical angle angular velocity is 0, and the q-axis current detection value is 0. Effect of the Invention

[0028] According to the present invention, in a power conversion device, it is possible to estimate the magnet temperature by using an estimation technique based on a voltage disturbance observer. [Brief description of the drawings]

[0029] [Figure 1] 1 is a block diagram showing a power conversion device according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing a temperature estimator according to the first embodiment. [Diagram 3] FIG. 2 is a block diagram showing a voltage disturbance observer in the first embodiment. [Figure 4] FIG. 11 is a diagram showing a simulation result at a constant speed in the first embodiment. [Diagram 5] FIG. 6 is a diagram showing a simulation result at zero speed in the first embodiment. [Figure 6] FIG. 11 is a block diagram showing a power conversion device according to a second embodiment. [Figure 7] FIG. 11 is a block diagram showing a temperature estimator according to the second embodiment. [Figure 8] FIG. 11 is a block diagram showing a voltage disturbance observer in the second embodiment. [Figure 9] FIG. 11 is a diagram showing a simulation result at a constant speed in the second embodiment. [Figure 10] FIG. 11 is a diagram showing a simulation result at zero speed in the second embodiment. [Figure 11] FIG. 11 is a block diagram showing a power conversion device according to a third embodiment. [Figure 12] 13 is a flowchart showing the process of an estimation classifier in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, first to third embodiments of the power conversion device according to the present invention will be described in detail with reference to Figs.

[0031] [Embodiment 1] In this embodiment 1, it is assumed that the magnet temperature and the stator temperature of the motor 8 are equal. The overall configuration of the power conversion device in this embodiment 1 is shown in Fig. 1. As shown in Fig. 1, the controller 1 includes a current controller 2, a two-phase to three-phase converter 3, a temperature estimator 4, a three-phase to two-phase converter 5, and an angular velocity output unit 6.

[0032] The current controller 2 calculates the d-axis current command value i d * ,q-axis current command value i q * and d-axis current detection value i d ,q-axis current detection value i q Based on the mechanical angle and angular velocity ω, the d-axis voltage command value v d * ,q-axis voltage command value v q * The two-phase to three-phase converter 3 outputs the d-axis voltage command value v d * ,q-axis voltage command value v q * is converted into two-phase to three-phase based on the phase θ, and three-phase voltage command values ​​of the uvw phases are output.

[0033] The inverter 7 outputs a voltage to the motor 8 based on the three-phase voltage command values ​​of the uv and w phases. The motor 8 is connected to a load 9. The motor 8 is provided with a rotational position sensor 10 for detecting a phase θ. A current detector 11 is provided on the output side of the inverter 7 for detecting a three-phase current detection value i uvw Detect.

[0034] The three-phase to two-phase converter 5 detects the three-phase currents i uvw is converted to three-phase / two-phase based on the phase θ, and the d-axis current detection value i d ,q-axis current detection value i q The angular velocity output unit 6 outputs the mechanical angular velocity ω based on the phase θ.

[0035] The temperature estimator 4 detects the d-axis current value i d ,q-axis current detection value i q and the mechanical angle velocity ω and the d-axis voltage command value v d * ,q-axis voltage command value v q * is input and the estimated temperature value T^ of the motor 8 is estimated.

[0036] The controller 1 outputs the three-phase voltage command value of the uvw phase to the inverter 7, and outputs the three-phase current detection value i uvw and the phase θ of the motor 8 is fed back. The temperature estimator 4 is inside the controller 1, and the d-axis voltage command value v d * ,q-axis voltage command value v q * , d-axis current detection value i d ,q-axis current detection value i q ,The mechanical angular velocity ω is input, and the temperature ,estimate value T^ is output.

[0037] 2 shows the configuration of the temperature estimator 4. The temperature estimator 4 includes a voltage disturbance observer (VDOB) 12, a pole pair multiplier 13, and a temperature calculator .

[0038] First, the q-axis voltage command value v q * and the q-axis current detection value i q Based on this, the q-axis voltage disturbance estimate v^ q vdob The pole pair number multiplier 13 multiplies the mechanical angle velocity ω by the pole pair number pp to estimate the electrical angle velocity ω e The temperature calculator 14 calculates the q-axis voltage disturbance estimate v^ q vdob , d-axis current detection value id ,q-axis current detection value i q , electrical angle velocity ω e The magnet temperature estimate value T^ is estimated using the above as an argument. The temperature calculator 14 performs the calculation shown in equation (1).

[0039]

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[0040] However, T b is the reference temperature, Φ n is the magnetic flux at the reference temperature, R n is the resistance at the reference temperature, α is the temperature coefficient of resistance, β is the temperature coefficient of magnetic flux, L d is the d-axis inductance.

[0041] A block diagram of the voltage disturbance observer 12 is shown in FIG. q L qn s+R an The subtractor 16 multiplies the q-axis voltage command value v q * The output of multiplier 15 is (L qn s+R an )i q The multiplier 17 subtracts the output of the subtractor 16 (v q * -(L qn s+R an )i q ) to g dis / s+g dis Multiply by L qn is the nominal value of the q-axis inductance, R an is the nominal value of the resistor, s is the Laplace operator, g dis is the cutoff frequency of the voltage disturbance observer 12. The specific calculation of the observer is as shown in equation (2).

[0042]

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[0043] <Derivation of the composition equation> The derivation of equation (1) will be described. First, the output of the voltage disturbance observer 12 is described by equation (3).

[0044]

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[0045] ΔL q is the nominal error of the q-axis inductance, ΔR a is the nominal error of the resistor, v^ emf is an estimate of the induced voltage. In this case, the variation of L is not taken into account, and the formula for the induced voltage, V emf =(L d i d +Φ)ω e Therefore, equation (3) can be transformed into equation (4), where Φ represents the magnetic flux.

[0046]

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[0047] Here, the magnetic flux Φ and the nominal error ΔR of the resistance a Assuming that is proportional to temperature, these can be expressed as equations (5) and (6), respectively, where T is temperature.

[0048]

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[0049]

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[0050] By substituting equations (5) and (6) into equation (4) and rearranging it with respect to temperature T, equation (1) which is the temperature calculator 14 can be derived.

[0051]

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[0052] <Simulation> The simulation conditions are as follows. Using Simulink (registered trademark), the simulation of the IPMSM at constant speed and zero speed and the temperature estimation were performed. The dynamics of the plant were expressed by equation (7). q is the q-axis inductance, R a is the resistance, L da is the d-axis inductance, Φ f indicates magnetic flux.

[0053]

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[0054] The magnetic flux and resistance here were changed according to the temperature as shown in equations (5) and (6). The temperature was changed using a ramp signal of [gradient 10°C / s, starting time 1 s later, initial temperature 60°C].

[0055] Vector control was implemented for the motor control. A PI controller was applied to the d-axis and q-axis currents. The d-axis current command value I d * was set to zero. In constant speed operation, the q-axis current command value I q * is determined by PI control of the speed, and the speed command is set to 10 rad / s. In the simulation at zero speed, the q-axis current command value I q * is set to 0.05 A, and friction is large and motor 8 does not move (in implementation, no driving force is applied to motor 8).

[0056] The constant speed simulation results are shown in Fig. 4. Fig. 4(a) shows the time series data of speed. The solid line shows the speed command value, and the dotted line shows the speed response value. It can be seen that the speed response value converges to the speed command value. Fig. 4(b) shows the time series response of temperature, with the solid line showing the magnet temperature response value and the dotted line showing the temperature estimation value. It can be seen that the temperature estimation value almost follows the ramp-shaped magnet response value, and that the temperature estimator 4 of this embodiment 1 is operating properly.

[0057] Next, the simulation results at zero speed are shown in Fig. 5. Fig. 5(a) shows the time series data of the speed. The dotted line shows the speed response value, and it can be seen that the speed is stationary at zero. Fig. 5(b) shows the time series response of the temperature, with the solid line showing the magnet temperature response value and the dotted line showing the temperature estimation value (T^ in equation (1)). It can be confirmed that the temperature estimation value almost follows the ramp-shaped magnet temperature response value, and that the temperature estimator 4 of this embodiment 1 is operating properly.

[0058] As described above, according to the first embodiment, the magnet temperature can be estimated in real time by inputting the d-axis and q-axis voltage command values, the d-axis and q-axis current detection values, and the mechanical angle and angular velocity.

[0059] Moreover, in the first embodiment, the temperature can be estimated without changing the current command such as harmonic superposition. In the first embodiment, the only calculation that includes dynamics such as differential and integral calculus is the voltage disturbance observer, and the other calculations are algebraic calculations that do not include dynamics. The only adjustment parameter related to dynamics is the cutoff frequency of the voltage disturbance observer, so that the gain can be easily adjusted.

[0060] [Embodiment 2] In the first embodiment, it is assumed that the magnet temperature and the stator temperature of the motor 8 are equal, but in the second embodiment, the magnet temperature and the stator temperature are estimated separately. The overall configuration of the power conversion device in the second embodiment is shown in FIG. 6. The difference from the first embodiment is that the output of the temperature estimator 4 is the stator temperature estimated value T^ st , magnet temperature estimate T^ pm These are the two points.

[0061] The configuration of the temperature estimator 4 in the second embodiment is shown in FIG. 7. First, a voltage disturbance observer (VDOB) 12 is implemented on each of the d-axis and q-axis, and a d-axis voltage command value v d * ,q-axis voltage command value v q * , d-axis current detection value i d ,q-axis current detection value i q Based on this, the d-axis voltage disturbance estimate v^d vdob ,q-axis voltage disturbance estimate v^ q vdob The pole pair number multiplier 13 multiplies the mechanical angle velocity ω by the pole pair number pp to estimate the electrical angle velocity ω e Next, the resistance and flux estimator 18 outputs the derived d-axis voltage disturbance estimate v^ d vdob ,q-axis voltage disturbance estimate v^ q vdob , d-axis current detection value i d ,q-axis current detection value i q , electrical angle velocity ω e Based on this, the nominal error estimate of the resistor, ΔR a Finally, the temperature calculator 14 calculates the nominal error estimate ΔR^ of the resistance. a ,Based on the magnetic flux estimate Φ^, the stator temperature estimate T^ st and magnet temperature estimate T^ pm Estimate.

[0062] The voltage disturbance observer 12 for the d- and q-axes in FIG. 7 is implemented by implementing a VDOB for each axis, and is specifically implemented as shown in FIG. 8. As shown in FIG. 8(a), in the d-axis, a multiplier 15d multiplies the d-axis current detection value i d L dn s+R an The subtractor 16d multiplies the d-axis voltage command value v d * The output of multiplier 15 is (L dn s+R an )i d The multiplier 17d subtracts the output of the subtractor 16d (v d * -(L dn s+R an )i d ) to g dis / s+g dis Multiply by L dn is the nominal value of the d-axis inductance. That is, the d-axis voltage disturbance observer 12 is expressed by the following equation (8).

[0063]

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[0064] As shown in FIG. 8(b), the q-axis voltage disturbance observer 12 is similar to that shown in FIG. 3 and formula (2) in the first embodiment.

[0065] In the resistance and magnetic flux estimator 18, the nominal error estimate of the resistance ΔR^ is calculated using equations (9) and (10). a and calculate the flux estimate Φ̂.

[0066]

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[0067]

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[0068] The temperature calculator 14 calculates the stator temperature estimate T^ from equations (11) and (12). st and magnet temperature estimate T^ pm Calculate.

[0069]

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[0070]

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[0071] <Derivation of the formula> The outputs of the d-axis and q-axis voltage disturbance observer 12 are expressed by equations (13) and (14). d is the nominal error of the d-axis inductance.

[0072]

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[0073]

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[0074] This time, the variable term of L is not considered. The formula for induced voltage v emf =(L d i q +Φ)ω e By substituting and rearranging, the nominal error estimate ΔR^ of the resistance is obtained as shown in (15) and (16). a and the flux estimate Φ̂ can be derived.

[0075]

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[0076]

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[0077] Here, the nominal error of the resistor, ΔR a and magnetic flux Φ are the stator temperature T st and magnet temperature T pm If we assume that it is proportional to, then it can be expressed as equations (17) and (18).

[0078]

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[0079]

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[0080] By substituting (17) and (18) into (13) and (14) and rearranging them with respect to temperature, the estimated stator temperature T^ st and magnet temperature estimate T^ pm The calculation formulas (11) and (12) can be derived as follows.

[0081]

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[0082]

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[0083] <Simulation results> Simulation conditions: Similar to the first embodiment, a simulation was performed using Simulink (registered trademark) during constant speed operation of the IPMSM, and temperature estimation was performed.

[0084] The dynamics of the plant uses equation (7), the same as in the first embodiment. The resistance and magnetic flux are also changed according to the temperature, as in equations (5) and (6). However, in this second embodiment, the stator temperature and magnet temperature are changed with different gradients. The magnet temperature is changed with a ramp signal of [gradient 10°C / s, start time 1 s later, initial temperature 60°C], the same as in the first embodiment, and the gradient of the stator temperature is set to 5°C / s.

[0085] The motor control is implemented by vector control as in the first embodiment. A PI controller is applied to the d-axis and q-axis currents. In the second embodiment, the d-axis current command value i d * was set to 0.1A. The q-axis current command value i q * is determined by PI control of the speed as in the first embodiment, and the speed command is set to 10 rad / s. The temperature estimator 4 used is the same as that in the second embodiment.

[0086] The results of a constant speed simulation in the second embodiment are shown in Fig. 9. Fig. 9(a) shows time series data of speed. As in the first embodiment, the solid line shows the speed command value, and the dotted line shows the speed response value. It can be seen that the speed response value converges to the speed command value.

[0087] Figure 9(b) shows the magnet temperature. The solid line shows the magnet temperature response value, and the dotted line shows the magnet temperature estimation value (T^ in Eq. (11)). pm ) is shown. As in the first embodiment, the magnet temperature estimated value approximately follows the ramp-shaped magnet temperature response value, and it can be confirmed that the temperature estimator 4 of the second embodiment operates appropriately.

[0088] Figure 9(c) shows the stator temperature. The solid line shows the stator temperature response value, and the dotted line shows the estimated stator temperature value. st ) tracks the stator temperature response value, and it can be seen that the temperature estimator 4 operates appropriately.

[0089] Simulation results at zero speed in this embodiment 2 are shown in Fig. 10. Fig. 10(a) shows time series data of speed, and it can be seen that the speed is zero and the vehicle is stationary.

[0090] Fig. 10(b) shows the time series response of the magnet temperature. Only the solid line magnet temperature response value is plotted, and the dotted line magnet temperature estimate value is not generated. It can be seen that in this embodiment 2, the magnet temperature cannot be estimated at zero speed.

[0091] Fig. 10(c) shows the time series response of the stator temperature. The solid line shows the stator temperature response value, and the dotted line shows the stator temperature estimated value. Regarding the stator temperature in Fig. 10(c), the stator temperature estimated value almost follows the ramp-like stator temperature response value, and it can be confirmed that the estimator of the second embodiment is operating properly.

[0092] As described above, according to the second embodiment, the magnet temperature and the stator temperature can be estimated simultaneously in real time by inputting the d-axis and q-axis voltage command values, the d-axis and q-axis current detection values, and the mechanical angle and angular velocity.

[0093] [Embodiment 3] When actually monitoring the temperature estimate, each method may not be able to calculate the temperature depending on the conditions. The third embodiment aims to combine the first and second embodiments and display the temperature estimate under as many conditions as possible.

[0094] The overall configuration of the power conversion device in the third embodiment is shown in Fig. 11. The temperature estimators 4 in the first and second embodiments are operated in parallel to obtain the temperature estimate T^ and the stator temperature estimate T^ st , magnet temperature estimate T^ pmThe estimated temperature value T^ and the stator temperature estimated value T^ are input to the estimation selector 19. The estimation selector 19 selects the estimated temperature value T^ and the stator temperature estimated value T^ according to a flowchart shown in FIG. st , magnet temperature estimate T^ pm The temperature estimation value T^ and the stator temperature estimation value T^ are displayed on the monitor. st , magnet temperature estimate T^ pm The electrical angular velocity ω e , d-axis current detection value i d ,q-axis current detection value i q If is all zero then the temperature cannot be displayed, otherwise either an estimate can be displayed.

[0095] The temperature calculation formula in the first embodiment is expressed by formula (1).

[0096]

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[0097] The denominator is Φ n ω e β+R n i q When α=0, that is, when the electrical angle velocity ω e and the q-axis current detection value i q If both are zero, the temperature estimate T^ cannot be calculated.

[0098] The temperature calculation formula in the second embodiment is expressed by formulas (9) to (12).

[0099]

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[0100]

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[0101]

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[0102]

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[0103] d-axis current detection value i d When is zero, the stator temperature estimate T^ st The electrical angle velocity ω e is zero or the nominal error estimate ΔR^ of the resistor a is zero (= d-axis current detection value i d When the magnet temperature estimate T^ is zero, pm It is not possible to calculate the above. By sorting out these conditions, the flow chart of Fig. 12 is obtained. The estimation selector 19 performs the process of the flow chart of Fig. 12.

[0104] As shown in FIG. 12, the electrical angular velocity ω e , d-axis current detection value i d ,q-axis current detection value i q ,Temperature estimate T^,Stator temperature estimate T^ st , magnet temperature estimate T^ pm Enter.

[0105] In S1, the d-axis current detection value i d Determine whether d-axis current detection value i d If it is not 0, the process moves to S2, and the d-axis current detection value i d If is 0, proceed to S3.

[0106] In S2, the electrical angular velocity ω e Determine whether the electrical angle and angular velocity ω are 0 or not. e If is 0, proceed to S4 and the stator temperature estimate T^ st and the electrical angle and angular velocity ω e If it is not 0, proceed to S5 and set the stator temperature estimate T^ st and the estimated magnet temperature T^ pm Display.

[0107] In S3, the electrical angular velocity ω e is 0 and the q-axis current detection value i qis 0, and the electrical angle angular velocity ω e is 0 and the q-axis current detection value i q If is 0, proceed to S6, otherwise proceed to S7. In S6, the temperature cannot be displayed. In S7, the temperature estimate T^ is displayed.

[0108] That is, the estimation selector 19 estimates the d-axis current detection value i d is not 0, and the electrical angle velocity ω e If is not 0, the stator temperature estimate T^ st and the estimated magnet temperature T^ pm The d-axis current detection value i d is not 0, and the electrical angle velocity ω e If is 0, the stator temperature estimate T^ st The d-axis current detection value i d is 0, and the electrical angular velocity ω e and q-axis current detection value i q If at least one of these is not 0, the temperature estimate T^ is displayed. The d-axis current detection value i d is 0, and the electrical angular velocity ω e is 0 and the q-axis current detection value i q If is 0, no estimates are displayed.

[0109] As described above, according to the third embodiment, the d-axis and q-axis voltage command values, the d-axis and q-axis current detection values, and the mechanical angle velocity are input, whereby the electrical angle velocity ω e , d-axis current detection value i d ,q-axis current detection value i q It is possible to display an appropriate temperature estimate in real time unless all of the above are zero.

[0110] Although the present invention has been described in detail above only with respect to the specific examples, it will be apparent to those skilled in the art that various modifications and variations are possible within the scope of the technical concept of the present invention, and it is natural that such modifications and variations fall within the scope of the claims. [Explanation of symbols]

[0111] 1. Controller 2. Current controller 3...Two-phase to three-phase converter 4…Temperature estimator 5...Three-phase to two-phase converter 6...Angular velocity output section 7…Inverter 8…Motor 9. Load 10...Rotational position sensor 11...Current detector 12…Voltage disturbance observer 13...Pole pair multiplier 14…Temperature calculator 15, 17…Multiplier 16…Subtractor 18…Resistance and magnetic flux estimator 19... Estimation sorter

Claims

1. a current controller that outputs a d-axis voltage command value and a q-axis voltage command value based on a d-axis current command value, a q-axis current command value, a d-axis current detection value, and a q-axis current detection value; a two-phase to three-phase converter that converts the d-axis voltage command value and the q-axis voltage command value into a two-phase to three-phase conversion and outputs a three-phase voltage command value; an inverter that outputs a voltage to a motor based on the three-phase voltage command value; a motor rotational position sensor for detecting a phase of the motor; a three-phase to two-phase converter that converts a three-phase current detection value of the output of the inverter into the d-axis current detection value and the q-axis current detection value; an angular velocity output unit that outputs a mechanical angular velocity based on the phase; a voltage disturbance observer that calculates a d-axis voltage disturbance estimated value and a q-axis voltage disturbance estimated value based on the d-axis voltage command value, the q-axis voltage command value, the d-axis current detection value, and the q-axis current detection value; a pole pair number multiplication unit that calculates an electrical angle velocity by multiplying the mechanical angle velocity by a pole pair number; a resistance / flux estimator that calculates a nominal error estimate of resistance and a magnetic flux estimate using equations (9) and (10); a temperature calculator that calculates a stator temperature estimate and a magnet temperature estimate of the motor based on the nominal error estimate of the resistance and the magnetic flux estimate; A power conversion device comprising: [0090] [0010] ΔR^a: Nominal error estimate of resistance v^d vdob: Estimated d-axis voltage disturbance value Lq: q-axis inductance iq: q-axis current detection value ωe: Electrical angle angular velocity i d : d-axis current detection value Φ^: Estimated magnetic flux v^qvdob: q-axis voltage disturbance estimate L d : d-axis inductance

2. 2. The power conversion device according to claim 1, wherein the voltage disturbance observer calculates the d-axis voltage disturbance estimated value and the q-axis voltage disturbance estimated value by the following equations (2) and (8). [0025] [0080] v ^ ｑ ｖｄｏｂ : Estimated q-axis voltage disturbance value v ^ ｄ ｖｄｏｂ : Estimated d-axis voltage disturbance value s: Laplace operator g ｄｉｓ : Cutoff frequency of the voltage disturbance observer v ｑ ＊ : q-axis voltage command value v ｄ ＊ :d-axis voltage command value L ｑｎ : Nominal value of q-axis inductance L ｄｎ : Nominal value of d-axis inductance R ａｎ : Nominal resistance value i ｑ : q-axis current detection value i ｄ : d-axis current detection value

3. The temperature calculator includes:

3. The power conversion device according to claim 1, wherein the estimated stator temperature value and the estimated magnet temperature value are calculated by equations (11) and (12). ##EQU00011## ##EQU00012## T^ ｓｔ : Estimated stator temperature ΔR ａ : Nominal error estimate of resistor R ｎ : Resistance at reference temperature α: Temperature coefficient of resistance T^ ｐｍ : Estimated magnet temperature Φ^: Estimated magnetic flux Φ ｎ : Magnetic flux at reference temperature β: Temperature coefficient of magnetic flux

4. a current controller that outputs a d-axis voltage command value and a q-axis voltage command value based on a d-axis current command value, a q-axis current command value, a d-axis current detection value, and a q-axis current detection value; a two-phase to three-phase converter that converts the d-axis voltage command value and the q-axis voltage command value into a two-phase to three-phase conversion and outputs a three-phase voltage command value; an inverter that outputs a voltage to a motor based on the three-phase voltage command value; a motor rotational position sensor for detecting a phase of the motor; a three-phase to two-phase converter that converts a three-phase current detection value of the output of the inverter into the d-axis current detection value and the q-axis current detection value; an angular velocity output unit that outputs a mechanical angular velocity based on the phase; a temperature estimator that calculates a temperature estimate, a stator temperature estimate, and a magnet temperature estimate of the motor based on the d-axis voltage command value, the q-axis voltage command value, the mechanical angular velocity, the d-axis current detection value, and the q-axis current detection value; an estimation selector that selects which of the temperature estimation value, the stator temperature estimation value, and the magnet temperature estimation value to display based on the d-axis current detection value, the q-axis current detection value, and an electrical angle velocity; Equipped with The temperature estimator a voltage disturbance observer that calculates a d-axis voltage disturbance estimated value and a q-axis voltage disturbance estimated value based on the d-axis voltage command value, the q-axis voltage command value, the d-axis current detection value, and the q-axis current detection value; a pole pair number multiplication unit that calculates the electrical angular velocity by multiplying the mechanical angular velocity by a pole pair number; a resistance / flux estimator that calculates a nominal error estimate of resistance and a magnetic flux estimate based on the d-axis voltage disturbance estimate value, the q-axis voltage disturbance estimate value, the d-axis current detection value, the q-axis current detection value, and the electrical angle angular velocity; a temperature calculator that calculates the temperature estimate based on the q-axis voltage disturbance estimate, the d-axis current detection value, the q-axis current detection value, and the electrical angle angular velocity, and calculates the stator temperature estimate and the magnet temperature estimate based on the nominal error estimate of the resistance and the magnetic flux estimate; A power conversion device comprising:

5. The estimation classifier comprises: When the d-axis current detection value is not 0 and the electrical angle angular velocity is not 0, the stator temperature estimate value and the magnet temperature estimate value are displayed; When the d-axis current detection value is not 0 and the electrical angle angular velocity is 0, the stator temperature estimation value is displayed. When the d-axis current detection value is 0 and at least one of the electrical angle velocity and the q-axis current detection value is not 0, the estimated temperature value is displayed; 5. The power conversion device according to claim 4, wherein when the d-axis current detection value is 0, the electrical angle angular velocity is 0, and the q-axis current detection value is 0, none of the temperature estimation value, the stator temperature estimation value, and the magnet temperature estimation value are displayed.

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