control device

Abstract

To provide a control device that can increase position estimation accuracy higher than that of a conventional position estimation method.SOLUTION: A control device 3 calculates an estimated extended induced voltage e^ which is an estimated value of an extended induced voltage produced in a motor M, calculates an estimated position θ^re1 which is an estimated value of the position of the motor M based on the estimated extended induced voltage e^, and when the motor M is restarted during inertial rotation of the motor M after a driving signal is no longer output to an inverter circuit 2, calculates the estimated extended induced voltage e^ based on an estimated angular velocity ω^re0 obtained based on information about the motor obtained before the driving signal is no longer output to the inverter circuit 2 or information about the motor obtained after the driving signal is no longer output to the inverter circuit 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Sensorless motor position control using extended induced voltage is known. For example, Non-Patent Literature 1 describes a restart algorithm in which, immediately after restarting from a free-run state, the current command value is set to 0 for a certain period of time to estimate the excited extended induced voltage, position estimation and polarity determination are performed in the low-speed stopping range where the extended induced voltage is insufficient, and position estimation is performed without signal superposition in the medium-to-high speed range where the extended induced voltage is sufficient. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Takamasa Kozakura, Shinji Michiki, "Study on restarting from free-run state in position sensorless control of permanent magnet synchronous motors using extended induced voltage," Proceedings of the Institute of Electrical Engineers of Japan (Motor Drives / Rotating Machines / Automotive Joint Workshop), Japan Institute of Electrical Engineers of Japan, May 30, 2021, pp. 63-68. [Overview of the project] [Problems that the invention aims to solve]

[0004] The position estimation method described in Non-Patent Document 1 does not provide highly accurate position estimation under all conditions, and there is a need for proposals for alternative position estimation methods.

[0005] This disclosure describes a control device capable of improving the accuracy of position estimation. [Means for solving the problem]

[0006] A control device relating to one aspect of this disclosure is a control device that generates a drive signal to control an inverter that drives a motor, comprising: a current value conversion unit that converts the 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 and a δ-axis current command value; a γ-δ voltage command value calculation unit that calculates a γ-axis voltage command value based on the γ-axis current value and the γ-axis current command value, and calculates a δ-axis voltage command value based on 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 outputs it to the inverter; and the γ-axis current value, δ-axis current value, γ-axis voltage command value, δ-axis current The system includes an estimation unit that calculates an estimated expanded induced voltage, which is an estimated value of the expanded induced voltage generated in the motor, based on the pressure command value and the estimated angular velocity, which is an estimated value of the motor's angular velocity, and calculates an estimated position, which is an estimated value of the motor's position, based on the estimated expanded induced voltage. The estimation unit calculates the estimated expanded induced voltage based on the estimated angular velocity obtained from information about the motor obtained before the drive signal was no longer output to the inverter, or from information about the motor obtained after the drive signal was no longer output to the inverter, when the motor is restarted while it is rotating by inertia after the drive signal has been stopped being output to the inverter.

[0007] In this control device, when the motor is restarted while rotating under inertia and the estimated extended induced voltage is first emitted, the estimated extended induced voltage is calculated using the estimated angular velocity of the motor obtained based on information about the motor. Therefore, the estimated extended induced voltage can be calculated using an estimated angular velocity close to the actual angular velocity, making it possible to improve the accuracy of position estimation.

[0008] In some embodiments, the motor information obtained after the inverter no longer outputs a drive signal may be the voltage across the motor terminals. In this case, the estimated extended induced voltage can be calculated using an estimated angular velocity close to the actual angular velocity, thereby improving the accuracy of position estimation.

[0009] In some embodiments, the estimation unit calculates the estimated angular velocity based on the estimated extended induced voltage, and the motor information obtained before the drive signal is no longer output to the inverter may be the estimated angular velocity calculated immediately before the drive signal is no longer output to the motor. In this case, the estimated extended induced voltage can be calculated using an estimated angular velocity close to the actual angular velocity, thereby improving the accuracy of position estimation. [Effects of the Invention]

[0010] According to this disclosure, the accuracy of position estimation can be improved. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram of a control system including a control device according to one embodiment. [Figure 2] Figure 2 is a block diagram showing the functional configuration of the arithmetic unit shown in Figure 1. [Figure 3] Figure 3 is a flowchart showing an example of the pre-reboot processing performed by the control device shown in Figure 1. [Modes for carrying out the invention]

[0012] A control device according to one embodiment will be described in detail below with reference to the attached drawings. In the description of the drawings, the same reference numerals are used for identical or equivalent elements, and redundant explanations are omitted.

[0013] Referring to Figure 1, the schematic configuration of a control system including a control device according to one embodiment will be described. Figure 1 is a schematic diagram of a control system including a control device according to one embodiment. The control system 1 shown in Figure 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 vehicles such as electric forklifts and plug-in hybrid vehicles. The control system 1 includes an inverter circuit 2, a control device 3, current sensors Se1, Se2, Se3, and a voltage sensor Se4.

[0014] The inverter circuit 2 drives the motor M with DC power supplied from the DC power supply PS. The inverter circuit 2 includes a capacitor C and switching elements SW1, SW2, SW3, SW4, SW5, and SW6.

[0015] Capacitor C smooths the voltage output from the DC power supply PS and input to the inverter circuit 2.

[0016] Switching elements SW1 to SW6 are, for example, IGBTs (Insulated Gate Bipolar Transistors). Switching element SW1 is the upper arm switching element of the U phase. Switching element SW2 is the lower arm switching element of the U phase. Switching element SW3 is the upper arm switching element of the V phase. Switching element SW4 is the lower arm switching element of the V phase. Switching element SW5 is the upper arm switching element of the W phase. Switching element SW6 is the lower arm switching element of the W phase. One terminal of capacitor C is connected to the positive terminal of the DC power supply PS and to the collector terminals of switching elements SW1, SW3, and SW5, respectively. The other terminal of capacitor C is connected to the negative terminal of the DC power supply PS and to the emitter terminals of switching elements SW2, SW4, and SW6, respectively.

[0017] 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 via current sensor Se1. 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 via current sensor Se2. 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 via current sensor Se3.

[0018] A drive signal is supplied from the control device 3 to the gate of each of the switching elements SW1 to SW6. Each of the switching elements SW1 to SW6 turns on or off based on the drive signal supplied to its gate. As each of the switching elements SW1 to SW6 turns on or off, the DC power output from the DC power supply PS is converted into three AC powers with a phase difference of 120 degrees from each other, and these AC powers are input to the three phase (U phase, V phase, and W phase) input terminals of the motor M, causing the rotor of the motor M to rotate.

[0019] Current sensors Se1 to Se3 are composed of Hall elements or shunt resistors, etc. Current sensor Se1 measures the U-phase current value I, which is the current value of the alternating current flowing through the U-phase of motor M. u The current sensor Se2 detects and outputs to the control device 3. The current sensor Se2 detects the V-phase current value I, which is the current value of the alternating current flowing through the V-phase of the motor M. v The current sensor Se3 detects and outputs to the control device 3. The current sensor Se3 detects the W-phase current value I, which is the current value of the alternating current flowing through the W-phase of the motor M. w The system detects this and outputs it to the control device 3. In this embodiment, there are three current sensors Se1 to Se3, but two may be used instead of three.

[0020] The voltage sensor Se4 is composed of a Hall element or a shunt resistor, etc. The voltage sensor Se4 is connected between the input terminal of the U layer of motor M and the input terminal of the V layer of motor M, and measures the line voltage V, which is the terminal voltage between the U layer and the V layer of motor M. uv It detects this and outputs it to the control device 3.

[0021] The control device 3 is a device that performs sensorless control of the motor M. The control device 3 drives the motor M by controlling the inverter circuit 2. The control device 3 includes a drive circuit 4 and an arithmetic unit 5.

[0022] The drive circuit 4 is constituted by an IC (Integrated Circuit) or the like. The drive circuit 4 compares the U-phase voltage command value V * u output from the arithmetic unit 5, the V-phase voltage command value V * v and the W-phase voltage command value V * w with a carrier wave (such as a triangular wave, a sawtooth wave, or a reverse sawtooth wave), and outputs a drive signal corresponding to the comparison result to each gate terminal of the switching elements SW1 to SW6.

[0023] The arithmetic unit 5 is an electronic control unit constituted by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (memory, Random Access Memory), and the like. For example, various functions of the arithmetic unit 5 are realized by a program stored in the ROM being loaded onto the RAM and executed by the CPU. The arithmetic unit 5 includes, as functional components, a command value generation unit 50 and a position estimation unit 55.

[0024] FIG. 2 is a block diagram showing in detail the functional configuration of the arithmetic unit shown in FIG. 1. As shown in FIG. 2, the arithmetic unit 5 includes, as the command value generation unit 50, a coordinate conversion unit 51, a γ-δ current command value output unit 52, a γ-δ voltage command value calculation unit 53, and a coordinate conversion unit 54.

[0025] The command value generation unit 50 includes the U-phase current value I u the V-phase current value I v the W-phase current value I w the γ-axis current command value I γ * and the δ-axis current command value I δ *Based on the U-phase voltage command value V * u V-phase voltage command value V * v , and W-phase voltage command value V * w The command value generation unit 50 generates the U-phase current value I u V-phase current value I v W-phase current value I w The system may also have a function that allows users to input the current values ​​of two phases, and then calculate the current value of the remaining phase from the input current values ​​of the two phases.

[0026] The coordinate transformation unit 51 included in the command value generation unit 50 converts the estimated position θ^ output from the position estimation unit 55. re1 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 It converts the current flowing through the motor M to the γ-axis current value I. γ and δ-axis current value I δ It functions as a current value conversion unit that converts to the estimated position θ^ re1 This is the position θ of the rotor of motor M. re1 This is an estimated value. Since this conversion method is well known, a detailed explanation is omitted here. The coordinate transformation unit 51 calculates the γ-axis current value I γ and δ-axis current value I δ This is output to the position estimation unit 55 and the γ-δ voltage command value calculation unit 53.

[0027] Note that "θ^ re1 In the notation ", the "^" is located to the upper right of "θ", but "θ^ re1 The symbol indicated on the upper arrow of the arrow pointing from the position estimation unit 55 to the command value generation unit 50 in Figure 1 has the same meaning. The same applies to other "^" notations. In this specification, the symbol "^" means an estimated value.

[0028] The γ-δ coordinate system is an estimated rotational coordinate system used in position sensorless control. In this system, the γ axis corresponds to the d axis of the dq coordinate system, and the δ axis corresponds to the q axis. The dq coordinate system is a rotational coordinate system where the d axis is the direction of the north pole of the magnet of the motor M, and the q axis is the direction perpendicular to the d axis.

[0029] The γ-δ current command value output unit 52 included in the command value generation unit 50 outputs the angular velocity command value ω input from an external source. * And the estimated angular velocity ω^ output from the position estimation unit 55. re The angular velocity difference Δω is calculated, and the torque command value T is obtained using the angular velocity difference Δω. * Calculate the estimated angular velocity ω^ re ω is the angular velocity of the rotor of motor M. re This is an estimated value.

[0030] The γ-δ current command value output unit 52 outputs the torque command value T * Using the γ-axis current command value I * γ and δ-axis current command value I * δ Calculate the γ-axis current command value I. * γ , and the δ-axis current command value I * δ Since the method for generating it is publicly known, a detailed explanation will be omitted here.

[0031] The γ-δ voltage command value calculation unit 53 included in the command value generation unit 50 calculates the γ-axis current command value I * γ and γ-axis current value I γ The difference between this and the γ-axis current command value ΔI * γ In addition to calculating the δ-axis current command value I * δ and the δ-axis current value I δ The difference between this and the δ axis current command value ΔI * δ The difference γ-axis current command value ΔI is calculated. * γ and the difference δ axis current command value ΔI * δ The γ-axis voltage command value V *γ and the δ-axis voltage command value V * δ are converted. That is, the γ-δ voltage command value calculation unit 53 calculates the γ-axis voltage command value V * γ based on the γ-axis current command value I γ and the γ-axis current value I * γ and calculates the δ-axis voltage command value V * δ based on the δ-axis current command value I δ and the δ-axis current value I * δ .

[0032] Note that since the generation methods of the γ-axis voltage command value V * γ and the δ-axis voltage command value V * δ are well-known, detailed descriptions are omitted here. The γ-δ voltage command value calculation unit 53 outputs the γ-axis voltage command value V * γ and the δ-axis voltage command value V * δ to the position estimation unit 55 and the coordinate conversion unit 54.

[0033] The coordinate conversion unit 54 included in the command value generation unit 50 converts the γ-axis voltage command value V re1 and the δ-axis voltage command value V * γ based on the estimated position θ^ * δ output from the position estimation unit 55 to the U-phase voltage command value V * u , the V-phase voltage command value V * v , and the W-phase voltage command value V * w . Since this conversion method is well-known, detailed descriptions are omitted here. The coordinate conversion unit 54 outputs the U-phase voltage command value V * u , the 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 use the γ-axis voltage command value V* γ and the δ-axis voltage command value V * δ It can be said that this unit functions as a drive signal output unit that converts the signal into a drive signal and outputs it to the inverter circuit 2.

[0034] The position estimation unit 55 estimates the estimated angular velocity ω^ re and estimated position θ^ re1 It has a function to calculate the γ-axis current value I. γ δ-axis current value I δ γ-axis voltage command value V * γ δ-axis voltage command value V * δ , the estimated angular velocity ω^ stored in memory (not shown) re Based on the estimated motor parameters that can be estimated in advance, the estimated extended electromotive force (EEMF) e generated in the motor M is calculated as the estimated extended electromotive force e^. That is, the position estimation unit 55 calculates the γ-axis current value I γ δ-axis current value I δ γ-axis voltage command value V * γ δ-axis voltage command value V * δ and estimated angular velocity ω^ re Based on this, it can be said that the estimated expanded induced voltage e^, which is an estimated value of the expanded induced voltage generated in the motor M, is calculated. Specifically, the position estimation unit 55 calculates the estimated expanded induced voltage e^ using the observer (motor model) shown in equation (1). The estimated expanded induced voltage e^ is the γ-axis estimated expanded induced voltage e^ γ And, the delta-axis estimated extended induced voltage e^ δ It includes and as vector components.

number

[0035] Note that p represents the time derivative operator d / dt. Estimated winding resistance R^, d-axis estimated inductance L^ d , and the estimated q-axis inductance L^ qThis is an estimated value of the motor parameters of the motor M being controlled, and is estimated in advance through measurements using the motor M. The reason why it is an estimated value rather than the actual value of the motor parameters of the motor M is that the motor parameters fluctuate depending on the current flowing through the motor M and the temperature.

[0036] Then, the position estimation unit 55 calculates the position error Δθ^ based on the estimated extended induced voltage e^. re Specifically, the position estimation unit 55 calculates the position error Δθ^ from the estimated extended induced voltage e^ using equation (2). re Calculate.

number

[0037] Next, the position estimation unit 55 calculates the position error Δθ^ re Based on this, the estimated angular velocity ω^ re The position estimation unit 55 calculates, for example, the position error Δθ^ re By multiplying this by a predetermined transfer function, the angular velocity ω^ re Calculate.

[0038] Then, the position estimation unit 55 calculates the estimated angular velocity ω^ re and position error Δθ^ re Based on this, the estimated position θ^ re1 The position estimation unit 55 calculates, for example, the estimated angular velocity ω^ re The provisional estimated position θ^ obtained by integrating and the position error Δθ^ re The corrected position error Δθ obtained by multiplying the given transfer function by the estimated position θ^ is added to the given position θ^ re1 The position error Δθ^ is calculated. re The system multiplies the calculated estimated angular velocity ω^ re and estimated position θ^ re1 Store the estimated angular velocity ω^ in memory. re The γ-δ current command value is output to the γ-δ current command value output unit 52, and the estimated position θ^ re1The coordinate transformation unit 51 and the coordinate transformation unit 54 output this.

[0039] Here, when the control device 3 receives a request to stop the motor M from the higher-level device, it does not forcibly stop the motor M, but instead controls the U-phase voltage command value V * u V-phase voltage command value V * v , and W-phase voltage command value V * w The output is stopped. Consequently, motor M enters a free-running state, rotating by inertia. Subsequently, when control device 3 receives a request to restart motor M from the higher-level device, it restarts motor M.

[0040] The pre-restart processing, which is the process performed by the control device 3 before it restarts after receiving a restart request, will be explained in detail below, with further reference to Figure 3. Figure 3 is a flowchart showing an example of the pre-restart processing performed by the control device in Figure 1.

[0041] When the control device 3 receives a request to stop the motor M from the higher-level device, the command value generation unit 50 of the control device 3 generates a U-phase voltage command value V for the drive circuit 4. * u V-phase voltage command value V * v , and W-phase voltage command value V * w The output of the system is stopped, and the estimated angular velocity ω^ stored in memory is also stopped. re and estimated position θ^ re1 The value is reset to zero (Step S1). This puts motor M into a free-running state where it rotates by inertia.

[0042] Subsequently, while the motor M is inertial rotation, the control device 3 periodically checks whether a restart request for the motor M has been received from the higher-level device (step S2). If the control device 3 determines that a restart request has been received (step S2; Yes), the position estimation unit 55 obtains information about the motor M after the command value generation unit 50 has stopped outputting a drive signal to the inverter circuit 2. That is, the position estimation unit 55 obtains the line voltage of the motor M (UV line voltage V) from the voltage sensor Se4 as information about the motor M. uv , or UW line voltage V uw , or VW line voltage V vw Obtain (Step S3).

[0043] Next, the position estimation unit 55 estimates the angular velocity of motor M at the time of receiving a motor restart request, which is the estimated angular velocity ω^, based on the acquired line voltage. re0 The calculated estimated angular velocity ω^ re0 The value is stored in memory (step S4). For example, the position estimation unit 55 estimates the angular velocity ω^ by multiplying the line voltage by a predetermined coefficient that has been stored in the control device 3 beforehand. re0 The following is calculated. The predetermined coefficient is set and stored based on the relationship between the line voltage and the angular velocity of motor M, which has been measured in advance for motor M. With this, the pre-restart processing is completed.

[0044] In the control device 3 described above, when the motor M receives a restart request while rotating inertia and first calculates the estimated extended induced voltage e^, the estimated angular velocity ω^ of the motor is obtained based on the information about the motor M. re0 The estimated extended induced voltage e^ is calculated using this method. According to this embodiment, the estimated angular velocity ω^ re Compared to calculating the estimated extended induced voltage e^ by setting it to zero, the estimated angular velocity ω^ is closer to the actual angular velocity. re By using this method, the estimated extended induced voltage e^ can be calculated, which improves the accuracy of position estimation.

[0045] Furthermore, in this embodiment, the information about motor M obtained after the command value generation unit 50 stops outputting a drive signal to motor M is the line voltage of motor M. In this case, the estimated angular velocity of the motor ω^ re This can be set to a value close to the actual angular velocity.

[0046] In the above embodiment, when first calculating the estimated extended induced voltage e^ after receiving a restart request, the estimated angular velocity ω^ of the motor is calculated from the line voltage of the motor M. re0 While this method uses the above, other information may also be used. For example, conventionally, when the control device 3 receives a stop request, the estimated angular velocity ω^ stored in memory is used. re Reset to zero, but it may also be kept without resetting to zero. In this case, the estimated angular velocity ω^ stored in memory re This is the estimated angular velocity ω^ calculated just before the drive signal was no longer output to inverter circuit 2. re Therefore, it can be said that this is information about motor M obtained before the drive signal is no longer output to inverter circuit 2. If the motor M is restarted immediately after the drive signal is no longer output, the estimated angular velocity ω^ re Compared to calculating the estimated extended induced voltage e^ by setting it to zero, the estimated angular velocity ω^ is closer to the actual angular velocity. re By using this method, the estimated extended induced voltage e^ can be calculated, which improves the accuracy of position estimation.

[0047] Furthermore, when the control device 3 receives a stop request, the estimated angular velocity ω^ stored in memory is used. re It resets to zero, but retains the estimated angular velocity ω^ stored in memory without resetting to zero. re And the estimated angular velocity ω^ from the time spent in a free-running state. re You may calculate this and store it in memory.

[0048] Although one embodiment of the present disclosure has been described in detail above, the control device relating to the present disclosure is not limited to the above embodiment.

[0049] In this embodiment, the pre-restart processing is performed when a request to stop the motor M is received, but it is not limited to this trigger. For example, the pre-restart processing may be started when, for some reason, a drive signal is no longer output to the inverter circuit 2 in the control system 1, and the drive of the motor M by the inverter circuit 2 is stopped. [Explanation of Symbols]

[0050] 1...Control system, 2...Inverter circuit, 3...Control device, 4...Drive circuit (drive signal output unit), 50...Command value generation unit, 51...Coordinate transformation unit (current value conversion unit), 52...γ-δ current command value output unit, 53...γ-δ voltage command value calculation unit, 54...Coordinate transformation unit (drive signal output unit), 55...Position estimation unit, M...Motor, SW1~SW6...Switching elements.

Claims

[Claim 1] A control device that generates a drive signal to control an inverter that drives a motor, A current value conversion unit that converts the current flowing through the motor into γ-axis current values ​​and δ-axis current values, A γ-δ current command value output unit that outputs γ-axis current command values ​​and δ-axis current command values, A γ-δ voltage command value calculation unit calculates a γ-axis voltage command value based on the γ-axis current value and the γ-axis current command value, and calculates a δ-axis voltage command value based on 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 signal and outputs it to the inverter, An estimation unit calculates an estimated expanded induced voltage, which is an estimated value of the expanded induced voltage generated in the motor, based on the γ-axis current value, the δ-axis current value, the γ-axis voltage command value, the δ-axis voltage command value, and the estimated angular velocity, which is an estimated value of the angular velocity of the motor, and calculates an estimated position, which is an estimated value of the position of the motor, based on the estimated expanded induced voltage. Equipped with, The control device calculates the estimated angular velocity based on the estimated extended induced voltage, and when restarting the motor while it is rotating by inertia after the drive signal is no longer output to the inverter, it calculates the estimated extended induced voltage based on the estimated angular velocity calculated immediately before the drive signal is no longer output to the motor, or based on the estimated angular velocity obtained based on the terminal voltage of the motor obtained after the drive signal is no longer output to the inverter.

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