Control device

Abstract

To provide a control device capable of improving the calculation accuracy of an estimation position error in a low speed range of a motor.SOLUTION: A control device includes a γ-δ current command value output part 52 for outputting a γ axis current command value I*γ including a γ axis harmonic content that changes by a first frequency and a δ axis current command value I*δ including a δ axis harmonic content that changes by the first frequency when a motor operates in a low-speed range, and an estimation part 55 for calculating instantaneous effective power and instantaneous reactive power, extracts a first pulsation component that changes by a second frequency twice as high as the first frequency from the instantaneous effective power, extracting a second pulsation component that changes by the second frequency from the instantaneous reactive power, and calculating an estimation position error Δθ^re on the basis of the first pulsation component and the second pulsation component when the motor operates in the low-speed range. The γ axis harmonic content has the same amplitude as the δ axis harmonic content, and the phase of γ axis harmonic content advances more than the phase of the δ axis harmonic content by 90 degrees.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a control device. [Background technology]

[0002] Position sensorless control, which controls a motor without using a position sensor, is known. For example, Non-Patent Document 1 describes position sensorless control that estimates an extended induced voltage in a dq coordinate system and performs position estimation over the entire speed range of a permanent magnet synchronous motor based on the estimated d-axis extended induced voltage and q-axis extended induced voltage. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Takumi Futamura, Shinji Michiki, “Full-Speed ​​Position Sensorless Control of Permanent Magnet Synchronous Motors Using Signal Superposition and Speed-Excited Extended Induced Voltage”, Transactions on Industrial Applications, Institute of Electrical Engineers of Japan, 2020, Vol. 140, No. 8, pp. 589-596 Summary of the Invention [Problem to be solved by the invention]

[0004] In position sensorless control as described in Non-Patent Document 1, the electrical angle error (estimated position error) between the d-axis of the dq coordinate system and the γ-axis of the γ-δ coordinate system in the low speed range of the motor is calculated using motor parameters such as the q-axis inductance. However, since errors may occur in the motor parameters, there is a risk that the calculation accuracy of the estimated position error may decrease.

[0005] The present disclosure describes a control device that can improve the calculation accuracy of an estimated position error in a low speed range of a motor. [Means for solving the problem]

[0006] A control device according to an aspect of the present disclosure is a device that generates a drive signal for controlling an inverter that drives a motor. The control device includes a current value converter that converts a current flowing through the motor into a γ-axis current value and a δ-axis current value, a γ-δ current command value output unit that outputs a γ-axis current command value including a γ-axis harmonic component that changes at a first frequency and a δ-axis current command value including a δ-axis harmonic component that changes at a first frequency when the motor is operating in a low-speed range lower than a predetermined angular velocity, a γ-δ voltage command value calculator that calculates a γ-axis voltage command value and a δ-axis voltage command value based on the γ-axis current value, the γ-axis current value, the δ-axis current value, and the δ-axis current command value, a drive signal output unit that converts the γ-axis voltage command value and the δ-axis voltage command value into a drive signal, and an estimator that calculates an estimated position error that is an estimated value of a position error between the γ-axis of the γ-δ coordinate system and the d-axis of the dq coordinate system. The γ-axis harmonic component has the same amplitude as the δ-axis harmonic component. The phase of the γ-axis harmonic component leads the phase of the δ-axis harmonic component by 90 degrees. When the motor is operating in a low speed range, the estimator calculates instantaneous active power and instantaneous reactive power using the specified γ-axis current value or the γ-axis current value, the specified δ-axis current value or the δ-axis current value, the specified γ-axis voltage value, and the specified δ-axis voltage value, extracts a first pulsation component that changes at a second frequency that is twice the first frequency from the instantaneous active power, and extracts a second pulsation component that changes at the second frequency from the instantaneous reactive power, and calculates an estimated position error based on the first pulsation component and the second pulsation component.

[0007] In the above control device, when the motor is operating in a low speed range, a γ-axis current command value including a γ-axis harmonic component that changes at a first frequency and a δ-axis current command value including a δ-axis harmonic component that changes at the first frequency are output. Then, instantaneous active power and instantaneous reactive power are calculated using the γ-axis current command value or the γ-axis current value, the δ-axis current command value or the δ-axis current value, the γ-axis voltage command value, and the δ-axis voltage command value. The γ-axis voltage command value and the δ-axis voltage command value are expressed by an equation including terms of the same amplitude having the phase of the estimated position error, and the phase of the γ-axis voltage command value term leads the phase of the δ-axis voltage command value by 90 degrees. The γ-axis harmonic component has the same amplitude as the δ-axis harmonic component, and the phase of the γ-axis harmonic component leads the phase of the δ-axis harmonic component by 90 degrees. Therefore, the instantaneous active power includes a first pulsation component having an initial phase represented by the estimated position error and varying at a second frequency that is twice the first frequency, and the instantaneous reactive power includes a second pulsation component having an initial phase represented by the estimated position error and varying at the second frequency, the first pulsation component and the second pulsation component having the same amplitude and not including the motor parameters. Since the estimated position error is calculated based on the first pulsation component and the second pulsation component, the estimated position error is not affected by the motor parameters. As a result, it is possible to improve the calculation accuracy of the estimated position error in the low speed range of the motor. Effect of the Invention

[0008] According to the present disclosure, it is possible to improve the calculation accuracy of the estimated position error in the low speed range of the motor. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a control system including a control device according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a functional configuration of the arithmetic unit shown in FIG. [Diagram 3] FIG. 3 is a diagram for explaining the relationship between the d axis and the γ axis. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a control device according to an embodiment will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicated descriptions will be omitted.

[0011] With reference to Fig. 1, a schematic configuration of a control system including a control device according to an embodiment will be described. Fig. 1 is a schematic configuration diagram of a control system including a control device according to an embodiment. The control system 1 shown in Fig. 1 is a system that performs position sensorless control of a motor (electric motor) M. The motor M is a position sensorless motor, for example, a permanent magnet synchronous motor (PMSM). The motor M is mounted on a vehicle such as an electric forklift and a plug-in hybrid vehicle. The control system 1 includes an inverter circuit 2 (inverter), a control device 3, and current sensors Se1, Se2, and Se3.

[0012] The inverter circuit 2 drives the motor M with DC power supplied from a DC power source PS. The inverter circuit 2 includes a capacitor C and switching elements SW1, SW2, SW3, SW4, SW5, and SW6.

[0013] The capacitor C smoothes the voltage that is output from the DC power supply PS and input to the inverter circuit 2.

[0014] The switching elements SW1 to SW6 are, for example, IGBTs (Insulated Gate Bipolar Transistors). The switching element SW1 is a switching element of the upper arm of the U phase. The switching element SW2 is a switching element of the lower arm of the U phase. The switching element SW3 is a switching element of the upper arm of the V phase. The switching element SW4 is a switching element of the lower arm of the V phase. The switching element SW5 is a switching element of the upper arm of the W phase. The switching element SW6 is a switching element of the lower arm of the W phase. One terminal of the capacitor C is connected to the positive terminal of the DC power supply PS and each of the collector terminals of the switching elements SW1, SW3, and SW5. The other terminal of the capacitor C is connected to the negative terminal of the DC power supply PS and each of the emitter terminals of the switching elements SW2, SW4, and SW6.

[0015] The connection point between the emitter terminal of switching element SW1 and the collector terminal of switching element SW2 is connected to the U-phase input terminal of motor M, and a current sensor Se1 that detects the U-phase current value is disposed on this connection line. The connection point between the emitter terminal of switching element SW3 and the collector terminal of switching element SW4 is connected to the V-phase input terminal of motor M, and a current sensor Se2 that detects the V-phase current value is disposed on this connection line. The connection point between the emitter terminal of switching element SW5 and the collector terminal of switching element SW6 is connected to the W-phase input terminal of motor M, and a current sensor Se3 that detects the W-phase current value is disposed on this connection line.

[0016] A drive signal is supplied to each gate of the switching elements SW1 to SW6 from the control device 3. Each of the switching elements SW1 to SW6 is turned on or off based on the drive signal supplied to the gate. By turning on or off each of the switching elements SW1 to SW6, the DC power output from the DC power supply PS is converted into three AC powers whose phases differ from each other by 120 degrees, and these AC powers are input to input terminals of the three phases (U phase, V phase, and W phase) of the motor M, causing the rotor of the motor M to rotate.

[0017] The current sensors Se1 to Se3 are configured with Hall elements or shunt resistors, etc. The current sensor Se1 detects a U-phase current value I u The current sensor Se2 detects a V-phase current value I v The current sensor Se3 detects the W-phase current value I w and outputs the detected current to the control device 3. In this embodiment, the control system 1 includes three current sensors (current sensors Se1 to Se3), but may include two current sensors.

[0018] The control device 3 is a device that performs position sensorless control of the motor M. The control device 3 drives the motor M by controlling the inverter circuit 2. The control device 3 generates a drive signal that controls the inverter circuit 2. The control device 3 includes a drive circuit 4 and a calculator 5.

[0019] The drive circuit 4 is configured with an IC (Integrated Circuit) or the like. The drive circuit 4 receives a U-phase voltage command value V * u , V-phase voltage command value V * v , and the W-phase voltage command value V * w The control circuit compares the signal with a carrier wave (such as a triangular wave, a sawtooth wave, or an inverse sawtooth wave) and outputs drive signals according to the comparison results to the gate terminals of the switching elements SW1 to SW6.

[0020] The arithmetic unit 5 is an electronic control unit composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc. For example, a program stored in the ROM is loaded onto the RAM and executed by the CPU, thereby realizing various functions of the arithmetic unit 5 shown in FIG.

[0021] Next, the functional configuration of the calculator 5 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a block diagram showing the functional configuration of the calculator shown in Fig. 1. Fig. 3 is a diagram for explaining the relationship between the d-axis and the γ-axis. As shown in Fig. 2, the calculator 5 includes, as functional components, a coordinate conversion unit 51, a γ-δ current command value output unit 52, a γ-δ voltage command value calculation unit 53, a coordinate conversion unit 54, and an estimation unit 55.

[0022] The coordinate conversion unit 51 converts the estimated position θ^ output from the estimation unit 55 into re Based on this, the U-phase current value I u , V-phase current value I v and W-phase current value I w The γ-axis current value I γ and δ-axis current value I δ That is, the coordinate conversion unit 51 converts the current flowing through the motor M into a γ-axis current value I γ and δ-axis current value I δ It functions as a current value converter that converts the estimated position θ^ re is the rotor position θ of the motor M re The estimated value of the position θ re is also called electrical angle. This conversion method is well known, so a detailed description will be omitted here.

[0023] The coordinate conversion unit 51 converts the γ-axis current value I γ and δ-axis current value I δ to the γ-δ voltage command value calculation unit 53 and the estimation unit 55. The coordinate conversion unit 51 receives the U-phase current value I u , V-phase current value I v and W-phase current value I wAmong these, current values ​​of two phases may be input, and the current value of the remaining one phase may be calculated from the input current values ​​of the two phases.

[0024] In addition, "θ^ re In the notation, "^" is located to the upper right of "θ", but in "θ^ re " has the same meaning as the symbol written on the arrow from the estimation unit 55 to the coordinate conversion unit 51 in Fig. 2. The same applies to other notations of "^". In this specification, the symbol "^" means an estimated value.

[0025] As shown in FIG. 3, at a position θ re is the angle between the α-axis of the α-β coordinate system and the d-axis of the dq coordinate system. re is the angle between the α-axis of the α-β coordinate system and the γ-axis of the γ-δ coordinate system. The α-β coordinate system is a fixed coordinate system. The dq coordinate system is a rotating coordinate system in which the direction of the north pole of the magnet of the motor M is the d-axis and the direction perpendicular to the d-axis is the q-axis. The γ-δ coordinate system is an estimated rotating coordinate system in position sensorless control, in which the axis equivalent to the d-axis of the dq coordinate system is the γ-axis and the axis equivalent to the q-axis is the δ-axis. The γ-axis of the γ-δ coordinate system and the d-axis of the dq coordinate system are related by the position error Δθ re Only one is off.

[0026] That is, the position error Δθ re is the true value of the angle between the γ-δ coordinate system's γ-axis and the d-axis of the dq coordinate system (or the angle between the δ-δ coordinate system's γ-δ coordinate system's δ-axis and the q-axis of the dq coordinate system). re is also called the electrical angle error. re When is zero, the γ-axis coincides with the d-axis and the δ-axis coincides with the q-axis.

[0027] The γ-δ current command value output unit 52 receives an angular velocity command value ω * and the estimated angular velocity ω^ output from the estimation unit 55 re The angular velocity difference Δω is calculated, and the torque command value T * Calculate the estimated angular velocity ω^ re is the angular velocity ω of the rotor of the motor M reThe γ-δ current command value output unit 52 estimates the torque command value T * The specified γ-axis current value and the specified δ-axis current value are calculated using the following equation: Note that, since the calculation method for the specified γ-axis current value and the specified δ-axis current value is known, a detailed description thereof will be omitted here.

[0028] When the motor M is operating in the medium to high speed range, the γ-δ current command value output unit 52 converts the γ-axis current command value and the δ-axis current command value calculated as described above into the γ-axis current command value I * γ and δ-axis current command value I * δ The γ-δ current command value output unit 52 outputs the estimated angular velocity ω^ to the γ-δ voltage command value calculation unit 53. re is equal to or greater than a predetermined angular velocity, it is determined that the motor M is operating in the medium to high speed range, and the estimated angular velocity ω^ re is lower than a predetermined angular velocity, the motor M is determined to be operating in the low-speed region. The predetermined angular velocity is an angular velocity that distinguishes the low-speed region from the medium-high-speed region, and for example, the position error Δθ can be calculated from the induced voltage without superimposing the harmonic components described later. re The angular velocity is a velocity range where the angular velocity can be estimated with a desired accuracy, and is determined in advance. The medium to high speed range is a speed range where the angular velocity is equal to or higher than the predetermined angular velocity. The low speed range is a speed range where the angular velocity is lower than the predetermined angular velocity.

[0029] The method of determining whether the motor M is operating in the low speed range or in the medium to high speed range is not limited to the above-mentioned method.

[0030] When the motor M is operating in the low speed range, the γ-δ current command value output unit 52 adds the γ-axis harmonic component I * γh By superimposing (adding) the γ-axis current command value I * γ Similarly, when the motor M is operating in the low speed range, the γ-δ current command value output unit 52 adds the δ-axis harmonic component I * δh By superimposing (adding) the δ-axis current command value I *δ The γ-δ current command value output unit 52 calculates the γ-axis current command value I * γ and δ-axis current command value I * δ to the γ-δ voltage command value calculation unit 53. That is, when the motor M is operating in the low speed range, the γ-δ current command value output unit 52 outputs the γ-axis harmonic component I * γh The γ-axis current command value I * γ and δ-axis harmonic component I * δh δ-axis current command value I * δ Output.

[0031] γ-axis harmonic component I * γh and δ-axis harmonic component I * δh is the amplitude I h and has an angular velocity ω h (first frequency), and the γ-axis harmonic component I * γh The phase of the δ-axis harmonic component I * δh The γ-axis harmonic component I * γh and δ-axis harmonic component I * δh is used. Note that the amplitude I h may be constant regardless of the angular velocity, or may be increased as the angular velocity decreases.

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[0032] The γ-δ voltage command value calculation unit 53 calculates the γ-axis voltage command value V * γ and δ-axis voltage command value V * δ The γ-δ voltage command value calculation unit 53 generates, for example, a γ-axis current command value I * γ and γ-axis current value I γThe difference between the γ-axis current command value ΔI * γ and calculates the δ-axis current command value I * δ and δ-axis current value I δ The difference between the δ-axis current command value ΔI * δ Calculate the differential γ-axis current command value ΔI * γ and the difference δ-axis current command value ΔI * δ is the γ-axis voltage command value V * γ and δ-axis voltage command value V * δ Convert to.

[0033] That is, the γ-δ voltage command value calculation unit 53 calculates the γ-axis current command value I * γ and γ-axis current value I γ and the δ-axis current command value I * δ and δ-axis current value I δ Based on this, the γ-axis voltage command value V * γ and δ-axis voltage command value V * δ Calculate the γ-axis voltage command value V * γ and δ-axis voltage command value V * δ The calculation method of the γ-δ voltage command value V * γ and δ-axis voltage command value V * δ to the coordinate conversion unit 54 and the estimation unit 55.

[0034] The coordinate conversion unit 54 converts the estimated position θ^ output from the estimation unit 55. re Based on this, the γ-axis voltage command value V * γ and δ-axis voltage command value V * δ The U-phase voltage command value V * u , V-phase voltage command value V * v , and the W-phase voltage command value V* w This conversion method is well known, so a detailed description will be omitted here. The coordinate conversion unit 54 converts the U-phase voltage command value V * u , V-phase voltage command value V * v , and the W-phase voltage command value V * w to the drive circuit 4. That is, the coordinate conversion unit 54 and the drive circuit 4 output the γ-axis voltage command value V * γ and δ-axis voltage command value V * δ It can be said that the drive signal output unit converts the signal into a drive signal.

[0035] The estimation unit 55 estimates the estimated position error Δθ^ re Calculate the estimated position error Δθ^ re is the position error Δθ re The estimation unit 55 estimates the estimated position error Δθ^ re Based on this, the estimated angular velocity ω^ re and the estimated position θ^ re The operation of the estimation unit 55 will be described in detail later.

[0036] Next, the estimated position error Δθ^ when the motor M is operating in the low speed range re The derivation theory of is explained.

[0037] Extended induced voltage model on the γ-δ coordinate system (γ-axis voltage value V γ and δ-axis voltage value V δ ) is expressed by equation (2). Note that p represents the time differential operator d / dt. The winding resistance R and the d-axis inductance L d , q-axis inductance L q , and the induced voltage constant K E are the motor parameters of the motor M to be controlled.

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[0038] pΔθ re , pL dand pL q can be considered to be zero, so pΔθ is added to equation (2). re =0, pL d =0 and pL q By substituting =0, we obtain equation (3).

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[0039] In equation (3), the γ-axis voltage value V γ , δ-axis voltage value V δ , γ-axis current value I γ , δ-axis current value I δ , d-axis current value I d , and the q-axis current value I q γ-axis voltage value V γh , δ-axis voltage value V δh , γ-axis current value I γh , δ-axis current value I δh , d-axis current value I dh , and the q-axis current value I qh By replacing the γ-axis voltage V γh , δ-axis voltage value V δh , γ-axis current value I γh , δ-axis current value I δh , d-axis current value I dh , and the q-axis current value I qh is the angular velocity ω h Note that the fundamental component is removed by a bandpass filter, which will be described later, so in order to simplify the following calculations, the fundamental component is removed in equation (4).

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[0040] Here, the high frequency instantaneous effective power P h (instantaneous active power) and high frequency instantaneous reactive power Q h (instantaneous reactive power) is derived by equations (5) and (6), respectively.

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[0041] By transforming equation (5) using equation (4), we obtain equation (7). Similarly, by transforming equation (6) using equation (4), we obtain equation (8).

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[0042] d-axis current value I dh and q-axis current value I qh are expressed by equations (9) and (10), respectively.

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[0043] By transforming equation (7) using equation (10), we obtain equation (11). Similarly, by transforming equation (8) using equation (9), we obtain equation (12).

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[0044] When the motor M is operating in the low speed range, the γ-axis harmonic component I * γh The γ-axis current command value I * γ and δ-axis harmonic component I * δh δ-axis current command value I *δ Since the harmonic components are extracted by a bandpass filter described later, the γ-axis harmonic component I * γh is the γ-axis current value I γh and the δ-axis harmonic component I * δh is the δ-axis current value I δh In this case, the γ-axis current value I γh The derivative pI γh and δ-axis current value I δh The derivative pI δh is expressed by equation (13).

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[0045] By rearranging equation (11) using equations (1), (9), (10), and (13), the high-frequency instantaneous effective power P when the motor M is operating in the low-speed range is obtained as shown in equation (14). h is formulated.

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[0046] By rearranging equation (12) using equations (1), (9), (10), and (13), the high-frequency instantaneous reactive power Q when the motor M is operating in the low-speed range is obtained as shown in equation (15). h is formulated.

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[0047] As shown in equation (14), the high-frequency instantaneous effective power P h Pulsating component P h(h) (First pulsating component) is sin2(ω h t-Δθ re ) changes according to the pulsating component P h(h) is the angular velocity ω h The angular velocity is twice that of 2ω. h(second frequency). Therefore, the angular velocity is 2ω h By applying a bandpass filter that passes the frequency band including h(h) is extracted.

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[0048] As shown in equation (15), the high-frequency instantaneous reactive power Q h Pulsating component Q h(h) (Second pulsating component) is cos2(ω h t-Δθ re ) changes according to the pulsating component Q h(h) is the angular velocity ω h The angular velocity is twice that of 2ω. h Therefore, the angular velocity changes as follows: h By applying a bandpass filter that passes the frequency band including h(h) is extracted.

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[0049] dq current phase θ ih(dq) is the pulsating component P h(h) and the pulsating component Q h(h) and is expressed by equation (18).

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[0050] Since the actual measured value lags behind the command value by π / 4 (rad), γδ current phase θ ih(γδ) is expressed by equation (19).

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[0051] Estimated position error Δθ^ re is the dq current phase θ ih(dq)and γδ current phase θ ih(γδ) and is expressed by equation (20).

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[0052] Based on the above-described derivation theory, the estimation unit 55 calculates the estimated position error Δθ^ re First, when the motor M is operating in the low speed range, the estimation unit 55 calculates the γ-axis current command value I * γ , δ-axis current command value I * δ , γ-axis voltage command value V * γ and δ-axis voltage command value V * δ Using this, the high frequency instantaneous effective power P h Pulsating component P h(h) and high frequency instantaneous reactive power Q h Pulsating component Q h(h) Specifically, the estimation unit 55 calculates the γ-axis current command value I * γ , δ-axis current command value I * δ , γ-axis voltage command value V * γ and δ-axis voltage command value V * δ Next, the estimation unit 55 calculates the instantaneous active power P and the instantaneous reactive power Q by applying the angular velocity 2ω h By applying a bandpass filter that passes the frequency band including h(h) Similarly, the estimation unit 55 extracts the pulsating component Q by applying the bandpass filter to the instantaneous reactive power Q. h(h) The above-mentioned determination method is used to determine whether the motor M is operating in the low speed range or in the medium to high speed range.

[0053] Next, the estimation unit 55 estimates the pulsating component P h(h) and pulsating component Q h(h) Based on the estimated position error Δθ^ re Specifically, the estimation unit 55 first calculates the pulsating component Ph(h) and the pulsating component Q h(h) Using the above, the dq current phase θ ih(dq) Then, the estimation unit 55 calculates the γδ current phase θ ih(γδ) Then, the estimation unit 55 calculates the dq current phase θ ih(dq) and γδ current phase θ ih(γδ) Using equation (20), the estimated position error Δθ^ re Calculate.

[0054] Next, the estimation unit 55 calculates the estimated position error Δθ^ re and a predetermined transfer function to obtain the estimated angular velocity ω^ re Then, the estimation unit 55 calculates the estimated angular velocity ω^ re and the estimated position error Δθ^ re Based on the estimated position θ^ re Calculate the estimated angular velocity ω^ re and the estimated position θ^ re The method of calculating the estimated position θ^ is publicly known, for example, as described in “Sensorless Control of a Salient-Pole Permanent Magnet Synchronous Motor Based on an Extended Induced Voltage Model”, Transactions of the Institute of Electrical Engineers of Japan, Vol. 122, No. 12, pp. 1088-1096, 2020, and therefore a detailed description thereof will be omitted here. re is output to the coordinate conversion unit 51 and the coordinate conversion unit 54, and the estimated angular velocity ω^ re to the γ-δ current command value output unit 52.

[0055] In the control device 3 described above, when the motor M is operating in the low speed range, the angular velocity ω h The γ-axis harmonic component I changes with * γh The γ-axis current command value I * γ and angular velocity ω h The δ-axis harmonic component I changes with * δh δ-axis current command value I * δ Then, as shown in equations (5) and (6), the γ-axis current command value I * γ , δ-axis current command value I* δ , γ-axis voltage command value V * γ and δ-axis voltage command value V * δ Using the above, the high frequency instantaneous effective power P h and high frequency instantaneous reactive power Q h is calculated.

[0056] As shown in equation (1), the γ-axis harmonic component I * γh is the δ-axis harmonic component I * δh The same amplitude as I h and the γ-axis harmonic component I * γh The phase of the δ-axis harmonic component I * δh As shown in equation (2), the γ-axis voltage command value V * γ and δ-axis voltage command value V * δ is the estimated position error Δθ^ re The γ-axis voltage command value V * γ The phase of the term is the δ-axis voltage command value V * δ Therefore, as shown in equation (14), the high-frequency instantaneous effective power P h is the estimated position error Δθ^ re and has an angular velocity of 2ω h The pulsating component P changes with h(h) As shown in equation (15), the high-frequency instantaneous reactive power Q h is the estimated position error Δθ^ re and has an angular velocity of 2ω h The pulsating component Q changes with h(h) Includes the pulsating component P h(h) and the pulsating component Q h(h) and have the same amplitude.

[0057] High frequency instantaneous effective power P h From the pulsating component P h(h)is extracted, and the high frequency instantaneous reactive power Q h From the pulsating component Q h(h) is extracted, and the pulsating component P h(h) and pulsating component Q h(h) Based on the dq current phase θ ih(dq) Furthermore, as shown in equation (20), the dq current phase θ ih(dq) and γδ current phase θ ih(γδ) From this, the estimated position error Δθ^ re As shown in equations (18) and (19), the dq current phase θ ih(dq) and γδ current phase θ ih(γδ) does not include motor parameters. Therefore, the estimated position error Δθ^ re Since is not affected by the motor parameters, it is possible to improve the calculation accuracy of the estimated position error in the low speed range of the motor M.

[0058] Although one embodiment of the present disclosure has been described in detail above, the control device according to the present disclosure is not limited to the above embodiment.

[0059] In the above embodiment, when the motor M is operating in the low speed range, the estimation unit 55 estimates the γ-axis current command value I * γ , δ-axis current command value I * δ , γ-axis voltage command value V * γ and δ-axis voltage command value V * δ Using this, the high frequency instantaneous effective power P h and high frequency instantaneous reactive power Q h However, instead of this configuration, when the motor M is operating in the low speed range, the estimation unit 55 calculates the γ-axis current value I γ , δ-axis current value I δ , γ-axis voltage command value V * γ and δ-axis voltage command value V * δ Using this, the high frequency instantaneous effective power P h and high frequency instantaneous reactive power Q h Specifically, the estimation unit 55 may calculate the γ-axis current value Iγ , δ-axis current value I δ , γ-axis voltage command value V * γ and δ-axis voltage command value V * δ respectively, the γ-axis current value I γh , δ-axis current value I δh , γ-axis voltage value V γh , and the δ-axis voltage value V δh Using the above, the high frequency instantaneous effective power P is calculated by equation (5). h Calculate the high-frequency instantaneous reactive power Q by using equation (6). h may be calculated.

[0060] The estimation unit 55 uses the angular velocity 2ω instead of the band pass filter. h A high-pass filter that passes the frequency band including h By applying h(h) Similarly, the estimation unit 55 may use the high-pass filter instead of the band-pass filter to extract the high-frequency instantaneous reactive power Q h By applying h(h) may be extracted.

[0061] The estimation unit 55 estimates the estimated position error Δθ^ re Specifically, the estimation unit 55 may detect the loss of synchronism of the motor M based on the estimated position error Δθ^ re and a predetermined threshold value, and the estimated position error Δθ^ re If the threshold value is exceeded, it is determined that the motor M has lost synchronism, and the estimated position error Δθ^ re is equal to or less than the threshold, it is determined that no step-out has occurred in the motor M. As the threshold, for example, π / 2 (rad) is used. [Explanation of symbols]

[0062] 2... inverter circuit (inverter), 3... control device, 4... drive circuit (drive signal output section), 51... coordinate conversion section (current value conversion section), 52... γ-δ current command value output section, 53... γ-δ voltage command value calculation section, 54... coordinate conversion section (drive signal output section), 55... estimation section, M... motor.

Claims

[Claim 1] A control device that generates a drive signal to control an inverter that drives a motor, a current value converter for converting a current flowing through the motor into a γ-axis current value and a δ-axis current value; a γ-δ current command value output unit that outputs, when the motor is operating in a low-speed range lower than a predetermined angular velocity, a γ-axis current command value including a γ-axis harmonic component that changes at a first frequency and a δ-axis current command value including a δ-axis harmonic component that changes at the first frequency; a γ-δ voltage command value calculation unit that calculates a γ-axis voltage command value and a δ-axis voltage command value based on the γ-axis current value, the γ-axis current command value, the δ-axis current value, and the δ-axis current command value; a drive signal output unit that converts the γ-axis voltage command value and the δ-axis voltage command value into the drive signals; an estimation unit that calculates an estimated position error that is an estimate of a position error between a γ-axis in a γ-δ coordinate system and a d-axis in a d-q coordinate system; Equipped with the γ-axis harmonic component has the same amplitude as the δ-axis harmonic component; the phase of the γ-axis harmonic component leads the phase of the δ-axis harmonic component by 90 degrees; the control device, when the motor is operating in the low speed range, the estimator calculates instantaneous active power and instantaneous reactive power using the specified γ-axis current value or the γ-axis current value, the specified δ-axis current value or the δ-axis current value, the specified γ-axis voltage value, and the specified δ-axis voltage value, extracts a first pulsation component that changes at a second frequency that is twice the first frequency from the instantaneous active power, and extracts a second pulsation component that changes at the second frequency from the instantaneous reactive power, and calculates the estimated position error based on the first pulsation component and the second pulsation component.

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