Motor Drive Control Device

Abstract

To obtain a configuration capable of reducing a position estimation error of a position estimation system and performing stable control even in a case where 180-degree energization one-pulse drive is performed, in a motor drive control device that controls drive of a motor by position sensorless control.SOLUTION: A motor drive control device 1 controls drive of an inverter 3 that has a plurality of switching elements SW1 to SW6 to control drive of a motor 2 supplied with power from the inverter 3. The motor drive control device 1 comprises: a first output voltage estimation unit 12 that estimates an output voltage of the inverter 3 on the basis of a voltage phase command θref; a position estimation unit 13 that estimates a rotational position of the motor 2 on the basis of the output voltage of the inverter 3 estimated by the first output voltage estimation unit 12; and a control signal generation unit 14 that generates a gate signal for making the inverter 3 output a rectangular wave voltage by using the rotational position estimated by the position estimation unit 13.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a motor drive control device that controls the drive of a motor.

Background Art

[0002] There is known a motor drive control device that controls the drive of a motor supplied with electric power from a switching circuit by controlling the drive of the switching circuit having a plurality of switching elements. As such a motor drive control device, for example, Non-Patent Document 1 discloses a control device provided with a position estimation system capable of operating until the PWM overmodulation drive of an inverter when driving a permanent magnet synchronous motor by sensorless vector control.

[0003] Non-Patent Document 1 describes a phenomenon in which a position estimation error occurs during the PWM overmodulation drive of an inverter. In Non-Patent Document 1, as a cause of such a position estimation error, a mismatch in the frequency components included in the voltage command value and the current feedback value used by the position estimation system is cited. Therefore, Non-Patent Document 1 describes using the estimated output voltage of the inverter as the voltage command input to the position estimation observer of the position estimation system as a method for preventing the above-mentioned mismatch in frequency components.

[0004] Note that in Non-Patent Document 1, the estimated output voltage is estimated in the process of estimating the harmonic voltage of the inverter. That is, the estimated output voltage is generated based on the voltage command calculated by the current control system.

Prior Art Documents

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in recent years, in addition to improving the utilization rate of the inverter power supply voltage, there are demands such as increasing the speed of the motor. Therefore, it has been considered to drive the inverter with 180-degree conduction angle and 180-degree conduction one-pulse drive so that the output voltage becomes a rectangular wave.

[0007] However, in the 180-degree conduction one-pulse drive, since the inverter output voltage becomes a rectangular wave with low-order harmonics superimposed, low-order harmonics are also superimposed on the output current of the motor. In sensorless control that performs drive control of the motor without detecting the rotational position of the motor, position estimation is performed based on the output current of the motor. Therefore, when the 180-degree conduction one-pulse drive is performed in the sensorless control, the position estimation accuracy of the position estimation system may be significantly reduced or the control may become unstable due to the current with low-order harmonics superimposed.

[0008] Therefore, conventionally, it has been considered difficult to combine the sensorless control and the 180-degree conduction one-pulse drive.

[0009] On the other hand, for the sensorless control in the 180-degree conduction one-pulse drive, a method of using the estimated output voltage of the inverter as the voltage command input to the position estimation observer of the position estimation system as disclosed in Non-Patent Document 1 described above can be considered. However, due to the following problems, even if the method disclosed in Non-Patent Document 1 described above is applied in the 180-degree conduction one-pulse drive, the sensorless control cannot be performed accurately and stably.

[0010] In the method disclosed in Non-Patent Document 1 described above, the estimated output voltage is generated based on a voltage command calculated by a current control system. However, in the 180-degree conduction one-pulse drive, the calculation of the current control system for controlling the current is not executed, and voltage phase control with the voltage phase as the control target is performed. Therefore, in the 180-degree conduction one-pulse drive, the estimated output voltage of the inverter cannot be calculated, and the method for reducing the position estimation error as disclosed in Non-Patent Document 1 described above cannot be used.

[0011] Therefore, even when performing 180-degree conduction one-pulse drive in sensorless control, there is a demand for a motor drive control device that can suppress a significant decrease in the position estimation accuracy of the position estimation system or destabilization of control.

[0012] An object of the present invention is to obtain a configuration capable of reducing the position estimation error of a position estimation system and performing stable control even when performing 180-degree conduction one-pulse drive in a motor drive control device that controls the drive of a motor by sensorless control.

Means for Solving the Problems

[0013] A motor drive control device according to an embodiment of the present invention is a motor drive control device that controls the drive of a motor supplied with power from a switching circuit by controlling the drive of the switching circuit having a plurality of switching elements. This motor drive control device includes a first output voltage estimation unit that estimates the output voltage of the switching circuit based on a voltage phase command, a position estimation unit that estimates the rotational position of the motor based on the output voltage of the switching circuit estimated by the first output voltage estimation unit, and a control signal generation unit that generates a control signal for causing the switching circuit to output a rectangular-wave voltage using the rotational position estimated by the position estimation unit (first configuration).

[0014] In the above configuration, based on the voltage phase command, the first output voltage estimation unit can estimate the output voltage of the switching circuit. Therefore, in a motor drive control device that controls the drive of a motor by sensorless control, when performing 180-degree conduction one-pulse drive in which a rectangular-wave voltage is output to the switching circuit, the output voltage input to the position estimation unit can be estimated without performing the calculation of the current control system.

[0015] Therefore, by inputting the output voltage of the switching circuit estimated by the first output voltage estimation unit to the position estimation unit, even in 180-degree conduction one-pulse drive without performing the calculation of the current control system, the rotational position of the motor can be accurately estimated. Thereby, in a motor drive control device that controls the drive of a motor by sensorless control, even when performing 180-degree conduction one-pulse drive, a configuration can be obtained in which the position estimation error of the position estimation system is reduced and stable control can be performed.

[0016] In the first configuration, the first output voltage estimation unit includes a switching timing estimation unit that estimates the switching timing of the plurality of switching elements in the switching circuit based on the voltage phase command, and an estimated output voltage calculation unit that estimates the output voltage of the switching circuit for each predetermined calculation cycle according to the switching timing estimated by the switching timing estimation unit (second configuration).

[0017] Thereby, according to the estimation result of the switching timing of the plurality of switching elements in the switching circuit based on the voltage phase command, the output voltage of the switching circuit can be estimated for each calculation cycle. Therefore, considering the switching timing, the output voltage of the switching circuit can be accurately estimated.

[0018] Therefore, in a motor drive control device that controls the drive of a motor by sensorless control, when performing 180-degree energization one-pulse drive, the position estimation error of the position estimation system can be more reliably reduced. Thus, the control of 180-degree energization one-pulse drive can be performed more stably.

[0019] In the second configuration, the estimated output voltage calculation unit includes a switching state estimation unit that estimates the switching states of the plurality of switching elements in the next calculation cycle and the next calculation cycle after the switching timing, and a voltage calculation unit that calculates the output voltage of the switching circuit according to the switching states of the plurality of switching elements estimated by the switching state estimation unit (third configuration).

[0020] Thereby, the switching states of the switching elements in the next calculation cycle and the next calculation cycle after that can be estimated, and the output voltage of the switching circuit can be calculated according to the estimation result. Thus, the output voltage of the switching circuit can be estimated more accurately in consideration of the switching states of the switching elements in the next calculation cycle and the next calculation cycle after that.

[0021] Therefore, in a motor drive control device that controls the drive of a motor by sensorless control, when performing 180-degree energization one-pulse drive, the position estimation error of the position estimation system can be more reliably reduced. Thus, the control of 180-degree energization one-pulse drive can be performed more stably.

[0022] In any one of the first to third configurations, the motor drive control device includes a second output voltage estimation unit that estimates the output voltage of the switching circuit based on a current command, and a PWM signal generation unit that generates a PWM signal for driving the plurality of switching elements in the switching circuit using the output voltage estimated by the second output voltage estimation unit. When performing drive control to output a rectangular wave voltage to the switching circuit, the output voltage estimated by the first output voltage estimation unit is input to the position estimation unit, while when performing drive control on the switching circuit using the PWM signal, the output voltage estimated by the second output voltage estimation unit is input (fourth configuration).

[0023] Thereby, the output voltage input to the position estimation unit can be switched according to whether the drive of the switching circuit is PWM drive or 180-degree conduction one-pulse drive. That is, when the drive of the switching circuit is PWM drive, the motor drive control device estimates the output voltage of the switching circuit based on a current command, while when the drive of the switching circuit is 180-degree conduction one-pulse drive, the motor drive control device estimates the output voltage of the switching circuit based on a voltage phase command.

[0024] In this way, by inputting the output voltage estimated according to the drive method of the inverter to the position estimation unit according to the drive method of the inverter, the position estimation error of the position estimation system can be reduced not only when the drive of the inverter is 180-degree conduction one-pulse drive but also when it is PWM drive. Therefore, the control of PWM drive and 180-degree conduction one-pulse drive can be stably performed.

[0025] Moreover, as described above, by enabling the drive of the inverter to be switched between 180-degree conduction one-pulse drive and PWM drive, the inverter can be driven in a more efficient drive method. Therefore, the motor can be driven more efficiently.

Advantages of the Invention

[0026] A motor drive control device according to an embodiment of the present invention includes a first output voltage estimator that estimates an output voltage of a switching circuit based on a voltage phase command, a position estimator that estimates a rotational position of the motor based on the output voltage of the switching circuit estimated by the first output voltage estimator, and a control signal generator that generates a control signal for causing the switching circuit to output a rectangular wave voltage using the rotational position estimated by the position estimator.

[0027] Accordingly, even in 180-degree conduction one-pulse drive in which calculations of a current control system are not performed, the rotational position of the motor can be accurately estimated. Therefore, in a motor drive control device that controls driving of a motor by sensorless position control, even when performing 180-degree conduction one-pulse drive, a configuration can be obtained that can reduce a position estimation error of a position estimation system and perform stable control.

Brief Description of the Drawings

[0028]

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[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals and their description will not be repeated.

[0030] [Embodiment 1] (Overall Configuration) FIG. 1 is a block diagram showing a schematic configuration of a motor drive control device 1 according to Embodiment 1 of the present invention. The motor drive control device 1 drives an inverter 3 (switching circuit) that drives and controls a motor 2 by one-pulse drive with 180-degree conduction according to a target speed ωref and a detected value Iuvw_ad of the motor current.

[0031] The motor 2 is a three-phase AC motor. That is, three-phase currents Iuvw are input to the motor 2 from the inverter 3. The configuration of the motor 2 is the same as the conventional configuration. Therefore, the description of the configuration of the motor 2 will be omitted. Note that the motor 2 may be a motor having a configuration other than a three-phase AC motor.

[0032] Inverter 3 outputs a three-phase current to motor 2 according to the gate signal output from motor drive control device 1. FIG. 2 is a circuit diagram showing an example of the circuit configuration of inverter 3. As shown in FIG. 2, inverter 3 has a plurality of switching elements SW1 to SW6 that constitute each phase of a three-phase full-bridge circuit. In the example shown in FIG. 2, switching element SW1 and switching element SW2 are electrically connected in series, switching element SW3 and switching element SW4 are electrically connected in series, and switching element SW5 and switching element SW6 are electrically connected in series. Their midpoints are each electrically connected to motor 2. Note that in the example shown in FIG. 2, a DC voltage Vdc is applied to inverter 3.

[0033] The switching elements SW1 to SW6 of inverter 3 have their switching states switched according to the gate signal output from gate signal switching unit 42 of motor drive control device 1. The gate signal, in the case of 180-degree conduction one-pulse drive, is a signal that switches the switching states of switching elements SW1 to SW6 every time the voltage phase command θref, which will be described later, changes by 60 degrees, as shown in FIG. 3. That is, the switching states of switching elements SW1 to SW6 of inverter 3 are determined according to the voltage phase command θref, which will be described later.

[0034] Note that the gate signal corresponds to a control signal that causes inverter 3 to output a rectangular-wave voltage.

[0035] Motor drive control device 1 estimates the rotational position of motor 2 using the output current of inverter 3, and after generating a gate signal for driving inverter 3 in 180-degree conduction one-pulse drive using the estimation result, outputs the gate signal to inverter 3. Although not particularly shown, motor drive control device 1 performs calculations for each control period synchronized with the carrier frequency used for PWM drive.

[0036] The motor drive control device 1 includes a speed control arithmetic unit 11, a first output voltage estimation unit 12, a position estimation unit 13, a control signal generation unit 14, and an analog signal acquisition unit 15.

[0037] The speed control arithmetic unit 11 calculates an advance angle amount θadvance from the target speed ωref and the estimated speed ωest of the motor 2 estimated by the position estimation unit 13. Specifically, the speed control arithmetic unit 11 calculates the advance angle amount θadvance based on the difference between the estimated speed ωest and the target speed ωref. The speed control arithmetic unit 11 is composed of, for example, a PI controller, an I controller, or the like.

[0038] The first output voltage estimation unit 12 estimates the estimated output voltage Vest_uvw_out (output voltage) of the inverter 3 using the advance angle amount θadvance output from the speed control arithmetic unit 11 and the estimated position θest of the motor 2 estimated by the position estimation unit 13. This estimated output voltage Vest_uvw_out is used in the calculation of the position estimation unit 13. The estimated position θest is the magnetic pole position of the rotor of the motor 2 estimated by the position estimation unit 13.

[0039] The first output voltage estimation unit 12 includes an adder 21, a switching timing estimation unit 22, and an estimated output voltage calculation unit 23.

[0040] The adder 21 adds the advance angle amount θadvance output from the speed control arithmetic unit 11 to the estimated position θest of the motor 2 estimated by the position estimation unit 13 to obtain a voltage phase command θref.

[0041] The switching timing estimation unit 22 estimates the timing at which the switching states of the switching elements SW1 to SW6 of the inverter 3 change (hereinafter referred to as the switching timing), using the voltage phase command θref calculated by the adder 21 and the estimated speed ωest of the motor 2 estimated by the position estimation unit 13. Specifically, the switching timing estimation unit 22 calculates the time Tsw (hereinafter referred to as the switching timing time) from the processing timing in the next control cycle to the timing at which the switching states of the switching elements SW1 to SW6 of the inverter 3 are switched, using the voltage phase command θref and the estimated speed ωest.

[0042] More specifically, the switching timing estimation unit 22 obtains the switching timing time Tsw using the following equations from the switching states of the switching elements SW1 to SW6 in the 180-degree conduction one-pulse drive shown in FIG. 3. (1) When 0 ≤ θref < π / 3 Tsw = (π / 3 - θref) / ωest (2) When π / 3 ≤ θref < 2π / 3 Tsw = (2π / 3 - θref) / ωest (3) When 2π / 3 ≤ θref < π Tsw = (π - θref) / ωest (4) When π ≤ θref < 4π / 3 Tsw = (4π / 3 - θref) / ωest (5) When 4π / 3 ≤ θref < 5π / 3 Tsw = (5π / 3 - θref) / ωest (6) When 5π / 3 ≤ θref < 2π Tsw = (2π - θref) / ωest

[0043] The switching timing time Tsw output from the switching timing estimation unit 22 is input to the estimated output voltage calculation unit 23 and an internal timer 41 described later. That is, the switching timing time Tsw is used when obtaining the estimated output voltage Vest_uvw_out of the inverter 3 and is also used when generating a gate signal in the control signal generation unit 14.

[0044] The estimated output voltage calculation unit 23 obtains the estimated output voltage Vest_uvw_out of the inverter 3 using the switching timing time Tsw output from the switching timing estimation unit 22. Specifically, the estimated output voltage calculation unit 23 uses the switching states of the switching elements SW1 to SW6 in the 180-degree conduction one-pulse drive shown in FIG. 3 and the switching timing time Tsw output from the switching timing estimation unit 22 to estimate the waveform of the output voltage of the inverter 3 from the processing start timing of the next control cycle to the processing start timing of the next control cycle (hereinafter referred to as the interval Tfix of the processing start timing). Then, the estimated output voltage calculation unit 23 obtains the average value of the output voltage within the next control cycle based on the estimated output voltage waveform, and sets this value as the estimated output voltage Vest_uvw_out. The estimated output voltage Vest_uvw_out includes the estimated output voltage of the u-phase, the estimated output voltage of the v-phase, and the estimated output voltage of the w-phase. Note that the processing start timing means the timing at which arithmetic processing is started in each control cycle.

[0045] The estimated output voltage calculation unit 23 includes a switching state estimation unit 24 and a voltage calculation unit 25.

[0046] The switching state estimation unit 24 estimates the waveform of the output voltage of the inverter 3 at the interval Tfix of the processing start timing based on the switching states of the switching elements SW1 to SW6 in the 180-degree conduction one-pulse drive shown in FIG. 3. Specifically, the switching state estimation unit 24 estimates which of the two types of patterns, the first pattern and the second pattern, the waveform of the output voltage of the inverter 3 at the interval Tfix of the processing start timing is, and outputs a signal of the estimation result to the voltage calculation unit 25.

[0047] The voltage calculation unit 25 obtains the average value of the output voltage within the next control cycle based on the result of the output voltage pattern estimated by the switching state estimation unit 24, and sets this value as the estimated output voltage Vest_uvw_out.

[0048] FIG. 4 is a diagram showing an example of the switching state of each switching element when the voltage phase command θref is π in 180-degree conduction one-pulse drive. As shown in an example in FIG. 4, when the inverter 3 is driven by 180-degree conduction one-pulse drive, the waveform of the output voltage of the inverter 3 at the interval Tfix of the processing start timing is divided into the following two patterns.

[0049] The first pattern is a pattern in which the switching states of the switching elements of all phases are constant at the interval Tfix of the processing start timing. In the case of this pattern, the switching timing time Tsw is larger than the interval Tfix of the processing start timing.

[0050] FIG. 5 is a diagram showing the output voltage of the u-phase when, for example, the switching element SW1 is in the on state and the switching element SW2 is in the off state in the case of the first pattern. In this case, the output voltage of the u-phase of the inverter 3 at the interval Tfix of the processing start timing is constant at Vdc / 2, which is half of the DC voltage Vdc input to the inverter 3. Therefore, the voltage calculation unit 25 outputs Vdc / 2, which is the average value of the output voltage of the u-phase at the interval Tfix of the processing start timing, as the estimated output voltage of the u-phase.

[0051] FIG. 6 is a diagram showing the output voltage of the u-phase when, for example, the switching element SW1 is in the off state and the switching element SW2 is in the on state in the case of the first pattern. In this case, the output voltage of the u-phase of the inverter 3 at the interval Tfix of the processing start timing is constant at -Vdc / 2. Therefore, the estimated output voltage calculation unit 23 outputs -Vdc / 2, which is the average value of the output voltage of the u-phase at the interval Tfix of the processing start timing, as the estimated output voltage of the u-phase.

[0052] Note that the voltage calculation unit 25 also obtains and outputs the estimated output voltages of the v-phase and w-phase of the inverter 3 in the case of the first pattern in the same manner as the estimated output voltage of the u-phase described above.

[0053] The second pattern is a pattern in which the switching state of the switching element of one phase changes at intervals Tfix of the processing start timing. In the case of this pattern, the switching timing time Tsw is smaller than the interval Tfix of the processing start timing.

[0054] In the case of the second pattern, at the time when the switching timing time Tsw has elapsed, the switching state of the switching element of one phase is switched. In this case, for example, as shown in FIG. 7, when the switching element SW1 is switched from the on state to the on state of the switching element SW2, the output voltage of the u-phase in the inverter 3 changes from Vdc / 2 to -Vdc / 2. The average value Vave_u of the output voltage of the u-phase at the interval Tfix of the processing start timing at this time is obtained by the following formula (7). Vave_u={Tsw×Vdc / 2+(Tfix-Tsw)×(-Vdc / 2)} / Tfix (7)

[0055] The voltage calculation unit 25 outputs the average value Vave_u of the output voltage of the u-phase as the estimated output voltage of the u-phase.

[0056] On the other hand, for example, as shown in FIG. 8, when the switching element SW2 is switched from the on state to the on state of the switching element SW1, the output voltage of the u-phase in the inverter 3 changes from -Vdc / 2 to Vdc / 2. The average value Vave_u of the output voltage of the u-phase at the interval Tfix of the processing start timing at this time is obtained by the following formula (8). Vave_u={Tsw×(-Vdc / 2)+(Tfix-Tsw)×Vdc / 2} / Tfix (8)

[0057] The voltage calculation unit 25 outputs the average value Vave_u of the output voltage of the u-phase as the estimated output voltage of the u-phase.

[0058] In the case of the second pattern, during the interval Tfix of the processing start timing, the phase for switching the switching state of the switching element is one of the three phases of the inverter 3. Therefore, when the switching state of the switching element of the u-phase is switched as described above during the interval Tfix of the processing start timing, the switching states of the switching elements of the v-phase and the w-phase are not switched. Thus, the estimated output voltages of the phases other than the phase whose switching state is switched are the same as those in the first pattern. For example, the estimated output voltage of the v-phase is -Vdc / 2, and the estimated output voltage of the w-phase is Vdc / 2.

[0059] The voltage calculation unit 25 can also obtain and output, in the same manner as the above-described estimated output voltage of the u-phase, the estimated output voltage of the v-phase in the case of the second pattern and when the switching state of the switching element of the v-phase is switched, or the estimated output voltage of the w-phase in the case of the second pattern and when the switching state of the switching element of the w-phase is switched.

[0060] As described above, the estimated output voltage calculation unit 23 can obtain the estimated output voltage Vest_uvw_out of the inverter 3 using the switching timing time Tsw output from the switching timing estimation unit 22.

[0061] The position estimation unit 13 estimates the rotational speed and the rotational position of the motor 2 using the estimated output voltage Vest_uvw_out output from the estimated output voltage calculation unit 23 and the motor current detection value Iuvw_ad acquired by the analog signal acquisition unit 15 described later. That is, the position estimation unit 13 obtains the estimated speed ωest and the estimated position θest of the motor 2 using the estimated output voltage Vest_uvw_out and the motor current detection value Iuvw_ad. The position estimation unit 13 is a so-called position estimation observer. The position estimation unit 13 may have any configuration as long as it can estimate the estimated speed ωest and the estimated position θest of the motor 2 using the estimated output voltage Vest_uvw_out and the motor current detection value Iuvw_ad.

[0062] The analog signal acquisition unit 15 outputs the result of detecting the current of the motor 2 to the position estimation unit 13 as the motor current detection value Iuvw_ad. The motor current detection value Iuvw_ad includes the motor current detection value of the u-phase, the motor current detection value of the v-phase, and the motor current detection value of the w-phase.

[0063] The control signal generation unit 14 generates a gate signal input to the inverter 3 using the switching timing time Tsw output from the switching timing estimation unit 22. The control signal generation unit 14 includes an internal timer 41 and a gate signal switching unit 42.

[0064] The internal timer 41 counts so as to generate an interrupt signal for the gate signal switching unit 42 at the switching timing time Tsw output from the switching timing estimation unit 22. That is, the internal timer 41 outputs an interrupt signal to the gate signal switching unit 42 at the switching timing time Tsw to switch the switching states of the switching elements SW1 to SW6 of the inverter 3.

[0065] With the configuration of the motor drive control device 1 as described above, the voltage phase command θref can be obtained using the target speed ωref of the motor 2, the estimated speed ωest of the motor 2, and the estimated position θest obtained by the position estimation unit 13.

[0066] Also, based on the voltage phase command θref, the timing at which the switching states of the switching elements SW1 to SW6 of the inverter 3 are switched can be estimated, and the estimated output voltage Vest_uvw_out of the inverter 3 can be obtained. Based on the obtained estimated output voltage Vest_uvw_out and the motor current detection value Iuvw_ad, the position estimation unit 13 can obtain the estimated speed ωest and the estimated position θest of the motor 2.

[0067] Therefore, in the motor drive control device 1 that performs 180-degree conduction one-pulse drive, the position estimation unit 13 can obtain the estimated speed ωest and the estimated position θest of the motor 2 without performing the calculation of the current control system.

[0068] In this embodiment, the motor drive control device 1 is a motor drive control device that controls the drive of a motor 2 supplied with power from an inverter 3 by controlling the drive of the inverter 3 having a plurality of switching elements SW1 to SW6. This motor drive control device 1 includes a first output voltage estimation unit 12 that estimates the output voltage of the inverter 3 based on a voltage phase command θref, a position estimation unit 13 that estimates the rotational position of the motor 2 based on the output voltage of the inverter 3 estimated by the first output voltage estimation unit 12, and a control signal generation unit 14 that generates a gate signal for outputting a rectangular wave voltage to the inverter 3 using the rotational position estimated by the position estimation unit 13.

[0069] In the above configuration, based on the voltage phase command θref, the first output voltage estimation unit 12 can estimate the output voltage of the inverter 3. Therefore, in the motor drive control device 1 that controls the drive of the motor 2 by sensorless position control, when performing 180-degree conduction one-pulse drive in which a rectangular wave voltage is output to the inverter 3, the output voltage input to the position estimation unit 13 can be estimated without performing the calculation of the current control system.

[0070] Therefore, by inputting the output voltage of the inverter 3 estimated by the first output voltage estimation unit 12 to the position estimation unit 13, the rotational position of the motor 2 can be accurately estimated even in 180-degree conduction one-pulse drive without performing the calculation of the current control system. As a result, in the motor drive control device 1 that controls the drive of the motor 2 by sensorless position control, even when performing 180-degree conduction one-pulse drive, a configuration can be obtained in which the position estimation error of the position estimation system is reduced and stable control can be performed.

[0071] The first output voltage estimation unit 12 includes a switching timing estimation unit 22 that estimates the switching timing of the switching states of the plurality of switching elements SW1 to SW6 in the inverter 3 based on the voltage phase command θref, and an estimated output voltage calculation unit 23 that obtains the output voltage of the inverter 3 for each predetermined calculation period according to the switching timing estimated by the switching timing estimation unit 22. In the present embodiment, the predetermined calculation period is the interval Tfix of the processing start timing. Note that the predetermined calculation period may be a period other than the interval Tfix of the processing start timing.

[0072] Thereby, according to the estimation result of the switching timing of the switching states of the plurality of switching elements SW1 to SW6 in the inverter 3 based on the voltage phase command θref, the output voltage of the inverter 3 can be obtained for each calculation period. Therefore, the output voltage of the inverter 3 can be accurately obtained in consideration of the switching timing.

[0073] Therefore, in the motor drive control device 1 that controls the drive of the motor 2 by sensorless position control, when performing 180-degree conduction one-pulse drive, the position estimation error of the position estimation system can be more reliably reduced. Therefore, the control of 180-degree conduction one-pulse drive can be performed more stably.

[0074] In the present embodiment, the estimated output voltage calculation unit 23 includes a switching state estimation unit that estimates the switching states of the plurality of switching elements SW1 to SW6 in the next calculation period and the next calculation period after that from the switching timing, and a voltage calculation unit that calculates the output voltage of the inverter 3 according to the switching states of the plurality of switching elements SW1 to SW6 estimated by the switching state estimation unit.

[0075] Accordingly, the switching states of the switching elements SW1 to SW6 in the next operation cycle and the operation cycle after that can be estimated, and the output voltage of the inverter 3 can be calculated according to the estimation result. Therefore, the output voltage of the inverter 3 can be obtained with higher accuracy in consideration of the switching states of the switching elements SW1 to SW6 in the next operation cycle and the operation cycle after that.

[0076] Therefore, in the motor drive control device 1 that controls the drive of the motor 2 by sensorless control, when performing 180-degree conduction one-pulse drive, the position estimation error of the position estimation system can be more reliably reduced. Therefore, the control of 180-degree conduction one-pulse drive can be performed more stably.

[0077] [Embodiment 2] FIG. 9 is a block diagram showing a schematic configuration of a motor drive control device 100 according to Embodiment 2 of the present invention. The motor drive control device 100 is different from the configuration of Embodiment 1 in that the input voltage Vuvw_out input to the position estimation unit 13 is switched depending on whether it is PWM drive or 180-degree conduction one-pulse drive. Therefore, hereinafter, the same components as those in Embodiment 1 will be denoted by the same reference numerals and the description thereof will be omitted, and only the differences from Embodiment 1 will be described.

[0078] As shown in FIG. 9, the motor drive control device 100 includes a speed control arithmetic unit 101 for PWM drive, a speed control arithmetic unit 102 for one-pulse drive, a first output voltage estimation unit 12, a current control arithmetic unit 111 (second output voltage estimation unit), an input voltage selector 112, a position estimation unit 13, a control signal generation unit 121, and an analog signal acquisition unit 115. Although not particularly shown, the motor drive control device 100 also performs operations every control cycle synchronized with the carrier frequency used for PWM drive, similar to the motor drive control device 1 of Embodiment 1.

[0079] The speed control calculation unit 101 for PWM drive generates a current command Idq_ref from the target speed ωref and the estimated speed ωest estimated by the position estimation unit 13. Specifically, the speed control calculation unit 101 for PWM drive generates the current command Idq_ref based on the difference between the estimated speed ωest and the target speed ωref. The current command Idq_ref includes a d-axis current command and a q-axis current command. Since the speed control calculation unit 101 for PWM drive has the same configuration as the conventional one, detailed description thereof is omitted.

[0080] The speed control calculation unit 102 for one-pulse drive has the same configuration as the speed control calculation unit 11 of Embodiment 1. Therefore, the speed control calculation unit 102 for one-pulse drive calculates the advance angle amount based on the difference between the estimated speed ωest and the target speed ωref. Detailed description of the configuration of the speed control calculation unit 102 for one-pulse drive is omitted.

[0081] The current control calculation unit 111 estimates the output voltage of the inverter 3 during PWM drive by using the current command Idq_ref output from the speed control calculation unit 101 for PWM drive and the motor current detection value Idq_ad acquired by the analog signal acquisition unit 115. Specifically, the current control calculation unit 111 obtains the estimated output voltage Vest_pwm_out (output voltage) of the inverter 3 during PWM drive based on the difference between the motor current detection value Idq_ad and the current command Idq_ref. The estimated output voltage Vest_pwm_out includes the estimated output voltage of the u-phase, the estimated output voltage of the v-phase, and the estimated output voltage of the w-phase. Since the configuration of this current control calculation unit 111 is also the same as the conventional one, detailed description thereof is omitted.

[0082] The input voltage selector 112 selects and outputs one of the estimated output voltage Vest_uvw_out output from the first output voltage estimator 12 and the estimated output voltage Vest_pwm_out output from the current control arithmetic unit 111 according to the driving method of the inverter 3. That is, when the inverter 3 is driving with 180-degree conduction one-pulse, the input voltage selector 112 outputs the estimated output voltage Vest_uvw_out output from the first output voltage estimator 12 to the position estimator 13 as the input voltage Vuvw_out of the position estimator 13, and when the inverter 3 is driving with PWM, the input voltage selector 112 outputs the estimated output voltage Vest_pwm_out output from the current control arithmetic unit 111 to the position estimator 13.

[0083] A selection command signal is input to the input voltage selector 112 from a controller (not shown). Specifically, when the inverter 3 is driving with PWM, for example, zero is input to the input voltage selector 112 from the controller as the selection command signal, and when the inverter 3 is driving with 180-degree conduction one-pulse, for example, one is input to the input voltage selector 112 from the controller as the selection command signal. The selection command signal may be a signal other than zero and one.

[0084] The position estimator 13 obtains the estimated speed ωest and the estimated position θest of the motor 2 using the estimated output voltage output from the input voltage selector 112 and the motor current detection value Idq_ad output from the analog signal acquisition unit 115. The analog signal acquisition unit 115 converts the three-phase output current Iuvw of the motor into a motor current detection value Idq_ad including the motor current detection value on the d-axis and the motor current detection value on the q-axis.

[0085] The control signal generation unit 121 generates a gate signal for PWM driving and a gate signal for 180-degree conduction one-pulse driving, and outputs the gate signal to the inverter 3 according to the driving method of the inverter 3. When performing PWM driving, the control signal generation unit 121 outputs, to the inverter 3, a gate signal generated using the estimated output voltage Vest_pwm_out generated by the current control arithmetic unit 111. When performing 180-degree conduction one-pulse driving, the control signal generation unit 121 outputs, to the inverter 3, a gate signal generated using the switching timing time Tsw generated by the switching timing estimation unit 22.

[0086] Specifically, the control signal generation unit 121 includes a PWM module 122, an internal timer 41, a gate signal switching unit 42, and a gate signal selector 123.

[0087] The PWM module 122 generates a gate signal that is a PWM signal using the estimated output voltage Vest_pwm_out output from the current control arithmetic unit 111. Specifically, the PWM module 122 compares the carrier frequency with the estimated output voltage Vest_pwm_out, and based on the comparison result, generates and outputs a gate signal for driving a plurality of switching elements SW1 to SW6 of the inverter 3. The PWM module 122 is a PWM signal generation unit that generates a PWM signal. The configuration of the PWM module 122 is the same as the conventional configuration.

[0088] The gate signal selector 123 selects one of the gate signal output from the PWM module 122 and the gate signal output from the gate signal switching unit 42 according to the driving method of the inverter 3, and outputs it to the inverter 3. Specifically, when the inverter 3 is driven by PWM, the gate signal selector 123 outputs the gate signal output from the PWM module 122 to the inverter 3. When the inverter 3 is driven by 180-degree conduction one-pulse, the gate signal selector 123 outputs the gate signal output from the gate signal switching unit 42 to the inverter 3.

[0089] A selection command signal is input to the gate signal selector 123 from a controller (not shown). Specifically, when the inverter 3 is PWM-driven, zero is input as the selection command signal from the controller to the gate signal selector 123, and when the inverter 3 is driven with 180-degree conduction one-pulse, 1 is input as the selection command signal from the controller to the gate signal selector 123. The selection command signal may be a signal other than zero and 1.

[0090] As described above, the motor drive control device 100 of the present embodiment further includes a current control arithmetic unit 111 that estimates the output voltage of the inverter 3 based on the current command Idq_ref, a PWM module 122 that generates a PWM signal for driving a plurality of switching elements SW1 to SW6 in the inverter 3 using the output voltage estimated by the current control arithmetic unit 111, and an input voltage selector 112 that inputs the output voltage estimated by the first output voltage estimator 12 to the position estimator 13 when performing drive control to output a rectangular wave voltage to the inverter 3, and inputs the output voltage estimated by the current control arithmetic unit 111 to the position estimator 13 when performing drive control of the inverter 3 using the PWM signal.

[0091] Thereby, according to whether the drive of the inverter 3 is PWM drive or 180-degree conduction one-pulse drive, the output voltage input to the position estimator 13 can be switched by the input voltage selector 112. That is, when the drive of the inverter 3 is PWM drive, the output voltage of the inverter 3 is estimated based on the current command, and when the drive of the inverter 3 is 180-degree conduction one-pulse drive, the output voltage of the inverter 3 is estimated based on the voltage phase command.

[0092] In this way, by selecting the output voltage estimated according to the driving method of the inverter 3 by the input voltage selector 112 according to the driving method of the inverter 3 and inputting it to the position estimation unit 13, the position estimation error of the position estimation system can be reduced not only when the inverter 3 is driven in 180-degree conduction one-pulse drive but also in PWM drive. Therefore, the control of PWM drive and 180-degree conduction one-pulse drive can be stably performed.

[0093] Moreover, as described above, by enabling the driving of the inverter 3 to be switched between 180-degree conduction one-pulse drive and PWM drive, the inverter 3 can be driven in a more efficient driving method. Therefore, the motor 2 can be driven more efficiently.

[0094] (Other Embodiments) The embodiments of the present invention have been described above. However, the above-described embodiments are merely examples for implementing the present invention. Therefore, the present invention is not limited to the above-described embodiments, and the above-described embodiments can be appropriately modified and implemented without departing from the spirit thereof.

[0095] In each of the above embodiments, the motor drive control device 1,100 performs calculations for each control cycle synchronized with the carrier frequency used for PWM drive. However, the motor drive control device may perform calculations at a cycle other than the carrier frequency.

[0096] In each of the above embodiments, the control signal generation unit 14, 121 generates a gate signal for switching the switching states of the switching elements SW1 to SW6 of the inverter 3 by outputting an interrupt signal from the internal timer 41 to the gate signal switching unit 42. However, the control signal generation unit may have other configurations as long as it can generate a gate signal for realizing 180-degree conduction one-pulse drive.

[0097] In each of the above embodiments, the configuration of the motor drive control device 1 that controls the drive of the three-phase AC motor 2 has been described. However, this is not the limit, and it may be applied to a control device that controls the drive of an AC motor having a plurality of phases other than three phases. That is, the motor 2 may have any configuration as long as it is a synchronous motor.

[0098] In Embodiment 2, the motor drive control device 100 includes an input voltage selector 112 and a gate signal selector 123. However, during PWM drive, the motor drive control device outputs a gate signal to the inverter and an estimated output voltage to the position estimation unit from the PWM drive control unit. During 180-degree conduction one-pulse drive, the motor drive control device may output a gate signal to the inverter and an estimated output voltage to the position estimation unit from the one-pulse drive control unit.

[0099] FIG. 10 is a control block diagram showing an example of the schematic configuration of a motor drive control device 200 having a PWM drive control unit 201 and a one-pulse drive control unit 202. In the following description, the same components as those in Embodiments 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

[0100] As shown in FIG. 10, the PWM drive control unit 201 includes a speed control arithmetic unit 101 for PWM drive, a current control arithmetic unit 111, and a PWM module 122. The one-pulse drive control unit 202 includes a speed control arithmetic unit 102 for one-pulse drive, a first output voltage estimation unit 12, and a control signal generation unit 14.

[0101] When the PWM drive control unit 201 PWM drives the inverter 3, it outputs a gate signal to the inverter 3 from the PWM module 122 and outputs an estimated output voltage Vest_pwm_out to the position estimation unit 13 from the current control arithmetic unit 111. At this time, the one-pulse drive control unit 202 does not output a signal to the inverter 3 and the position estimation unit 13.

[0102] When the one-pulse drive control unit 202 drives the inverter 3 with 180-degree conduction one-pulse drive, it outputs a gate signal to the inverter 3 from the gate signal switching unit 42 and outputs the estimated output voltage Vest_uvw_out to the position estimation unit 13 from the first output voltage estimation unit 12. At this time, the PWM drive control unit 201 does not output a signal to the inverter 3 and the position estimation unit 13.

[0103] As described above, when performing drive control to output a rectangular wave voltage to the inverter 3, the estimated output voltage Vest_uvw_out (output voltage) estimated by the first output voltage estimation unit 12 is input to the position estimation unit 13, while when performing drive control on the inverter 3 with a PWM signal, the estimated output voltage Vest_pwm_out (output voltage) estimated by the current control arithmetic unit 111 is input.

[0104] Thereby, the estimated output voltage input to the position estimation unit 13 can be switched according to whether the drive of the inverter 3 is PWM drive or 180-degree conduction one-pulse drive. That is, when the drive of the inverter 3 is PWM drive, the motor drive control device 200 estimates the output voltage of the inverter 3 based on the current command, while when the drive of the inverter 3 is 180-degree conduction one-pulse drive, it estimates the output voltage of the inverter 3 based on the voltage phase command.

[0105] In this way, by inputting the output voltage estimated according to the drive method of the inverter 3 to the position estimation unit 13 according to the drive method of the inverter 3, the position estimation error of the position estimation system can be reduced not only when the drive of the inverter 3 is 180-degree conduction one-pulse drive but also when it is PWM drive. Therefore, the control of PWM drive and 180-degree conduction one-pulse drive can be stably performed.

[0106] Moreover, as described above, by enabling the drive of the inverter 3 to be switched between 180-degree conduction one-pulse drive and PWM drive, the inverter 3 can be driven in a more efficient drive mode. Therefore, the motor 2 can be driven more efficiently.

Industrial Applicability

[0107] The present invention is applicable to a motor drive control device that controls the drive of a motor supplied with power from a switching circuit by controlling the drive of the switching circuit having a plurality of switching elements.

Explanation of Reference Numerals

[0108] 1, 100, 200 Motor drive control device 2 Motor 3 Inverter (switching circuit) 11 Speed control arithmetic unit 12 First output voltage estimation unit 13 Position estimation unit 14, 121 Control signal generation unit 15, 115 Analog signal acquisition unit 21 Adder 22 Switching timing estimation unit 23 Estimated output voltage arithmetic unit 24 Switching state estimation unit 25 Voltage calculation unit 41 Internal timer 42 Gate signal switching unit 101 Speed control arithmetic unit for PWM drive 102 Speed control arithmetic unit for one-pulse drive 111 Current control arithmetic unit (second output voltage estimation unit) 112 Input voltage selector 122 PWM module (PWM signal generation unit) 123 Gate signal selector 201 PWM drive control unit 202 One-pulse drive control unit SW1~SW6 Switching element

Claims

1. A motor drive control device that controls the drive of a motor powered by a switching circuit by controlling the drive of the switching circuit having a plurality of switching elements, a first output voltage estimation unit that estimates the output voltage of the switching circuit based on a voltage phase command; a position estimation unit that estimates the rotational position of the motor based on the output voltage of the switching circuit estimated by the first output voltage estimation unit; a control signal generation unit that generates a control signal for causing the switching circuit to output a rectangular wave voltage using the rotational position estimated by the position estimation unit; comprising: a motor drive control device.

2. In the motor drive control device according to Claim 1, the first output voltage estimation unit includes a switching timing estimation unit that estimates the switching timing of the plurality of switching elements in the switching circuit based on the voltage phase command; and an estimated output voltage calculation unit that estimates the output voltage of the switching circuit every predetermined calculation cycle according to the switching timing estimated by the switching timing estimation unit; having: a motor drive control device.

3. In the motor drive control device according to Claim 2, the estimated output voltage calculation unit includes a switching state estimation unit that estimates the switching states of the plurality of switching elements in the next calculation cycle and the next calculation cycle after that from the switching timing; and a voltage calculation unit that calculates the output voltage of the switching circuit according to the switching states of the plurality of switching elements estimated by the switching state estimation unit; having: a motor drive control device.

4. In the motor drive control device according to any one of Claims 1 to 3, a second output voltage estimation unit that estimates the output voltage of the switching circuit based on a current command; and a PWM signal generation unit that generates a PWM signal for driving the plurality of switching elements in the switching circuit using the output voltage estimated by the second output voltage estimation unit; further comprising: When performing drive control to cause the switching circuit to output a rectangular-wave voltage, the output voltage estimated by the first output voltage estimation unit is input to the position estimation unit, while when performing drive control of the switching circuit with the PWM signal, the output voltage estimated by the second output voltage estimation unit is input to the position estimation unit. Motor drive control device.

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