JP7709038B2 - Motor drive control device - Google Patents

Description

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

A motor drive control device is known that controls the drive of a motor supplied with power from a switching circuit by controlling the drive of the switching circuit having multiple switching elements. For example, Non-Patent Document 1 discloses an example of such a motor drive control device, which is equipped with a position estimation system that can operate even when the inverter is driven by PWM overmodulation when driving a permanent magnet synchronous motor by position sensorless vector control.

Non-Patent Document 1 describes the phenomenon in which a position estimation error occurs when an inverter is driven by PWM overmodulation. Non-Patent Document 1 cites a mismatch in frequency components contained in the voltage command value and current feedback value used by the position estimation system as a cause of such a position estimation error. Therefore, Non-Patent Document 1 describes a method of preventing the above-mentioned mismatch in frequency components by using the estimated output voltage of the inverter as the voltage command input to the position estimation observer of the position estimation system.

In addition, in the non-patent document 1, the estimated output voltage is estimated in the process of estimating the harmonic voltage of the inverter. In other words, the estimated output voltage is generated based on the voltage command calculated by the current control system.

Kosuke Kondo et al., "Position Estimation System Capable of Inverter Overmodulation Drive for Position Sensorless Vector Control of Permanent Magnet Synchronous Motors," IEEJ Transactions on Industrial Applications, Vol. 136, No. 11, 2016, pp. 829-836

In recent years, there has been a demand for higher motor speeds in addition to improved utilization of the inverter power supply voltage. For this reason, it has been considered to drive the inverter with a 180-degree current single pulse so that the current angle is 180 degrees and the output voltage is a square wave.

However, in the 180-degree energization one-pulse drive, the inverter output voltage becomes a square wave with low-order harmonics superimposed on it, so the motor output current also has low-order harmonics superimposed on it. In position sensorless control, which controls the drive of a 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 energization one-pulse drive is performed in the position sensorless control, the current with low-order harmonics superimposed on it may significantly reduce the position estimation accuracy of the position estimation system or cause control to become unstable.

Therefore, it was previously thought that it would be difficult to combine the position sensorless control with the 180-degree energization single-pulse drive.

In response to this, a method is conceivable in which the estimated output voltage of the inverter is used as a voltage command to be input to a position estimation observer of a position estimation system for the position sensorless control in the 180-degree energization one-pulse drive, as disclosed in the above-mentioned non-patent document 1. However, due to the following problems, even if the method disclosed in the above-mentioned non-patent document 1 is applied to the 180-degree energization one-pulse drive, the position sensorless control cannot be performed with high accuracy and stability.

In the method disclosed in the above-mentioned non-patent document 1, the estimated output voltage is generated based on a voltage command calculated by a current control system. However, in the above-mentioned 180-degree current one-pulse drive, calculations of the current control system that controls the current are not performed, and voltage phase control that controls the voltage phase is performed. Therefore, in the above-mentioned 180-degree current one-pulse drive, the estimated output voltage of the inverter cannot be calculated, and the method of reducing position estimation errors such as that disclosed in the above-mentioned non-patent document 1 cannot be used.

Therefore, there is a demand for a motor drive control device that can prevent a significant decrease in the position estimation accuracy of the position estimation system and control instability, even when performing 180-degree current conduction single-pulse drive in position sensorless control.

The object of the present invention is to provide a configuration for a motor drive control device that controls the drive of a motor using position sensorless control, capable of reducing the position estimation error of the position estimation system and performing stable control even when performing 180-degree energization one-pulse drive.

A motor drive control device according to one embodiment of the present invention is a motor drive control device that controls the drive of a switching circuit having a plurality of switching elements, thereby controlling the drive of the motor supplied with power from the switching circuit. This motor drive control device includes a first output voltage estimator that estimates the output voltage of the switching circuit based on a voltage phase command, a position estimator that estimates the 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 uses the rotational position estimated by the position estimator to generate a control signal that causes the switching circuit to output a square wave voltage (first configuration).

In the above configuration, the output voltage of the switching circuit can be estimated by the first output voltage estimator based on the voltage phase command. Therefore, in a motor drive control device that controls the drive of a motor by position sensorless control, when performing 180-degree current one-pulse drive that outputs a square wave voltage to the switching circuit, the output voltage to be input to the position estimator can be estimated without performing calculations of the current control system.

Therefore, by inputting the output voltage of the switching circuit estimated by the first output voltage estimation unit to the position estimation unit, the rotational position of the motor can be estimated with high accuracy even in 180-degree current one-pulse drive that does not perform calculations of the current control system. As a result, in a motor drive control device that controls the drive of a motor by position sensorless control, a configuration is obtained that can reduce the position estimation error of the position estimation system and perform stable control even when 180-degree current one-pulse drive is performed.

In the first configuration, the first output voltage estimator includes a switching timing estimator that estimates the switching timing of the switching states of the multiple switching elements in the switching circuit based on the voltage phase command, and an estimated output voltage calculator that estimates the output voltage of the switching circuit for each predetermined calculation period according to the switching timing estimated by the switching timing estimator (second configuration).

This makes it possible to estimate the output voltage of the switching circuit for each calculation period according to the estimated switching timing of the switching states of multiple switching elements in the switching circuit based on the voltage phase command. Therefore, the output voltage of the switching circuit can be accurately estimated taking into account the switching timing.

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

In the second configuration, the estimated output voltage calculation unit has a switching state estimation unit that estimates the switching states of the multiple switching elements in the next calculation cycle and the 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 multiple switching elements estimated by the switching state estimation unit (third configuration).

This makes it possible to estimate the switching state of the switching element in the next calculation cycle and the calculation cycle after that, and calculate the output voltage of the switching circuit according to the estimation result. Therefore, it is possible to more accurately estimate the output voltage of the switching circuit by taking into account the switching state of the switching element in the next calculation cycle and the calculation cycle after that.

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

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

This allows the output voltage input to the position estimation unit to be switched depending on whether the switching circuit is driven by PWM drive or 180-degree current single-pulse drive. That is, when the switching circuit is driven by PWM drive, the motor drive control device estimates the output voltage of the switching circuit based on a current command, whereas when the switching circuit is driven by 180-degree current single-pulse drive, the motor drive control device estimates the output voltage of the switching circuit based on a voltage phase command.

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

Moreover, as described above, by making it possible to switch between 180-degree energization one-pulse drive and PWM drive, the inverter can be driven with a more efficient drive method. This allows the motor to be driven more efficiently.

A motor drive control device according to one 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 uses the rotational position estimated by the position estimator to generate a control signal that causes the switching circuit to output a square wave voltage.

This allows the motor's rotational position to be estimated with high accuracy even in 180-degree current one-pulse drive, which does not perform calculations in the current control system. Therefore, in a motor drive control device that controls the drive of a motor using position sensorless control, a configuration is obtained that can reduce the position estimation error of the position estimation system and perform stable control even when 180-degree current one-pulse drive is performed.

FIG. 1 is a control block diagram showing a schematic configuration of a motor drive control device according to a first embodiment. FIG. 2 is a circuit diagram showing a schematic configuration of the inverter. FIG. 3 is a diagram showing the switching state of each switching element in the 180-degree conduction single-pulse drive. FIG. 4 is a diagram showing an example of the switching state of each switching element when the voltage phase command is π in 180-degree conduction single-pulse drive. FIG. 5 is a diagram showing the u-phase output voltage in the first pattern when, for example, the switching element SW1 is in the on state and the switching element SW2 is in the off state. FIG. 6 is a diagram showing the u-phase output voltage in the first pattern when, for example, the switching element SW1 is in the OFF state and the switching element SW2 is in the ON state. FIG. 7 is a diagram showing the u-phase output voltage when, for example, switching element SW1 is switched from an on state to switching element SW2 in the second pattern. FIG. 8 is a diagram showing the u-phase output voltage when, for example, switching element SW2 is switched from an on state to switching element SW1 is switched on in the second pattern. FIG. 9 is a block diagram showing a schematic configuration of a motor drive control device according to the second embodiment. FIG. 10 is a control block diagram showing an example of a schematic configuration of a motor drive control device having a PWM drive control section and a one-pulse drive control section.

The following describes in detail an embodiment of the present invention with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and their description will not be repeated.

[Embodiment 1]
(Overall composition)
1 is a block diagram showing a schematic configuration of a motor drive control device 1 according to a first embodiment of the present invention. The motor drive control device 1 drives an inverter 3 (switching circuit) that controls the drive of a motor 2 with 180-degree energization single-pulse drive in accordance with a target speed ωref and a motor current detection value Iuvw_ad.

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

The inverter 3 outputs three-phase current to the motor 2 in response to a gate signal output from the motor drive control device 1. FIG. 2 is a circuit diagram showing an example of the circuit configuration of the inverter 3. As shown in FIG. 2, the 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, the switching element SW1 and the switching element SW2 are electrically connected in series, the switching element SW3 and the switching element SW4 are electrically connected in series, and the switching element SW5 and the switching element SW6 are electrically connected in series. Their midpoints are each electrically connected to the motor 2. In the example shown in FIG. 2, a DC voltage Vdc is applied to the inverter 3.

The switching states of the switching elements SW1 to SW6 of the inverter 3 are switched in response to a gate signal output from the gate signal switching unit 42 of the motor drive control device 1. In the case of 180-degree energization one-pulse drive, the gate signal is a signal that switches the switching state of the 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. In other words, the switching state of the switching elements SW1 to SW6 of the inverter 3 is determined in response to the voltage phase command θref, which will be described later.

The gate signal corresponds to a control signal that causes inverter 3 to output a square wave voltage.

The motor drive control device 1 estimates the rotational position of the motor 2 using the output current of the inverter 3, and generates a gate signal for driving the inverter 3 with a 180-degree current single pulse using the estimation result, and then outputs the gate signal to the inverter 3. Although not specifically shown, the motor drive control device 1 performs calculations for each control period synchronized with the carrier frequency used for PWM drive.

The motor drive control device 1 has a speed control calculation unit 11, a first output voltage estimator 12, a position estimator 13, a control signal generator 14, and an analog signal acquirer 15.

The speed control calculation unit 11 calculates the 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 calculation unit 11 calculates the advance angle amount θadvance based on the difference between the target speed ωref and the estimated speed ωest. The speed control calculation unit 11 is configured, for example, by a PI controller or an I controller.

The first output voltage estimator 12 estimates the estimated output voltage Vest_uvw_out (output voltage) of the inverter 3 using the advance angle θadvance output from the speed control calculator 11 and the estimated position θest of the motor 2 estimated by the position estimator 13. This estimated output voltage Vest_uvw_out is used for the calculation of the position estimator 13. The estimated position θest is the magnetic pole position of the rotor of the motor 2 estimated by the position estimator 13.

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

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

The switching timing estimation unit 22 estimates the timing at which the switching state of the switching elements SW1 to SW6 of the inverter 3 is switched (hereinafter referred to as 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 uses the voltage phase command θref and the estimated speed ωest to calculate the time Tsw (hereinafter referred to as switching timing time) from the processing timing in the next control cycle to the timing at which the switching state of the switching elements SW1 to SW6 of the inverter 3 is switched.

More specifically, the switching timing estimation unit 22 obtains the switching timing time Tsw from the switching states of the switching elements SW1 to SW6 in the 180-degree conduction single-pulse drive shown in FIG. 3, using the following equations.
(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

The switching timing time Tsw output from the switching timing estimation unit 22 is input to the estimated output voltage calculation unit 23 and the internal timer 41 described below. That is, the switching timing time Tsw is used when calculating 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.

The estimated output voltage calculation unit 23 uses the switching timing time Tsw output from the switching timing estimation unit 22 to calculate the estimated output voltage Vest_uvw_out of the inverter 3. Specifically, the estimated output voltage calculation unit 23 uses the switching state of the switching elements SW1 to SW6 in the 180-degree energization 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 processing start timing interval Tfix). Then, the estimated output voltage calculation unit 23 calculates the average value of the output voltage in 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. The processing start timing means the timing at which the calculation process is started in each control cycle.

The estimated output voltage calculation unit 23 has a switching state estimation unit 24 and a voltage calculation unit 25.

The switching state estimation unit 24 estimates the waveform of the output voltage of the inverter 3 during the interval Tfix of the processing start timing based on the switching states of the switching elements SW1 to SW6 in the 180-degree current single-pulse drive shown in Figure 3. Specifically, the switching state estimation unit 24 estimates which of two types of patterns, a first pattern and a second pattern described below, the waveform of the output voltage of the inverter 3 during the interval Tfix of the processing start timing is, and outputs the estimation result as a signal to the voltage calculation unit 25.

The voltage calculation unit 25 calculates the average value of the output voltage within the next control period based on the output voltage pattern estimated by the switching state estimation unit 24, and sets this value as the estimated output voltage Vest_uvw_out.

Figure 4 shows an example of the switching state of each switching element when the voltage phase command θref is π in 180-degree energization one-pulse drive. As shown in the example in Figure 4, when inverter 3 is driven with 180-degree energization one-pulse drive, the waveform of the output voltage of inverter 3 during the processing start timing interval Tfix can be divided into the following two patterns.

The first pattern is a pattern in which the switching state of the switching elements of all phases is constant for the processing start timing interval Tfix. In this pattern, the switching timing time Tsw is greater than the processing start timing interval Tfix.

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

Figure 6 is a diagram showing the output voltage of the u-phase in the first pattern, for example, when switching element SW1 is in the off state and switching element SW2 is in the on state. In this case, the output voltage of the u-phase of the inverter 3 during 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 during the interval Tfix of the processing start timing, as the estimated output voltage of the u-phase.

The voltage calculation unit 25 also calculates 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.

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

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

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

8, when the switching element SW2 is switched from an on state to an on state of the switching element SW1, the u-phase output voltage of the inverter 3 changes from −Vdc/2 to Vdc/2. The average value Vave_u of the u-phase output voltage during the processing start timing interval Tfix at this time is calculated by the following formula (8).
Vave_u={Tsw×(-Vdc/2)+(Tfix-Tsw)×Vdc/2}/Tfix (8)

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

In the case of the second pattern, the phase in which the switching state of the switching element is switched during the processing start timing interval Tfix is one of the three phases of the inverter 3. Therefore, when the switching state of the u-phase switching element is switched as described above during the processing start timing interval Tfix, the switching states of the v-phase and w-phase switching elements are not switched. Therefore, the estimated output voltages of phases other than the phase in which the switching state is switched are the same as 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.

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

As described above, the estimated output voltage calculation unit 23 can calculate 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.

The position estimation unit 13 estimates the rotational speed and 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 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 is capable of estimating the estimated speed ωest and estimated position θest of the motor 2 using the estimated output voltage Vest_uvw_out and the motor current detection value Iuvw_ad.

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.

The control signal generating unit 14 generates a gate signal to be input to the inverter 3 using the switching timing time Tsw output from the switching timing estimating unit 22. The control signal generating unit 14 has an internal timer 41 and a gate signal switching unit 42.

The internal timer 41 counts to generate an interrupt signal to 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 state of the switching elements SW1 to SW6 of the inverter 3.

By configuring 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 and the estimated speed ωest and estimated position θest of the motor 2 obtained by the position estimation unit 13.

In addition, 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 change can be estimated, and the estimated output voltage Vest_uvw_out of the inverter 3 can be obtained. From the obtained estimated output voltage Vest_uvw_out and the motor current detection value Iuvw_ad, the position estimator 13 can determine the estimated speed ωest and estimated position θest of the motor 2.

Therefore, in the motor drive control device 1 that performs 180-degree energization single-pulse drive, the estimated speed ωest and estimated position θest of the motor 2 can be obtained by the position estimation unit 13 without performing calculations in the current control system.

In this embodiment, the motor drive control device 1 is a motor drive control device that controls the drive of the inverter 3 having multiple switching elements SW1 to SW6, thereby controlling the drive of the motor 2 supplied with power from the inverter 3. This motor drive control device 1 includes a first output voltage estimator 12 that estimates the output voltage of the inverter 3 based on a voltage phase command θref, a position estimator 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 estimator 12, and a control signal generator 14 that uses the rotational position estimated by the position estimator 13 to generate a gate signal that causes the inverter 3 to output a square wave voltage.

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

Therefore, by inputting the output voltage of the inverter 3 estimated by the first output voltage estimator 12 to the position estimator 13, the rotational position of the motor 2 can be estimated with high accuracy even in 180-degree current one-pulse drive that does not perform calculations of the current control system. As a result, in the motor drive control device 1 that controls the drive of the motor 2 by position sensorless control, a configuration is obtained that can reduce the position estimation error of the position estimation system and perform stable control even when 180-degree current one-pulse drive is performed.

The first output voltage estimation unit 12 has a switching timing estimation unit 22 that estimates the switching timing of the switching states of the multiple 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 calculates 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 this 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.

As a result, the output voltage of the inverter 3 can be calculated for each calculation period according to the estimated switching timing of the switching states of the multiple switching elements SW1 to SW6 in the inverter 3, which is based on the voltage phase command θref. Therefore, the output voltage of the inverter 3 can be calculated with high accuracy, taking into account the switching timing.

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

In this embodiment, the estimated output voltage calculation unit 23 has a switching state estimation unit that estimates the switching states of the multiple switching elements SW1 to SW6 in the next calculation cycle and the calculation cycle 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 multiple switching elements SW1 to SW6 estimated by the switching state estimation unit.

This makes it possible to estimate the switching states of the switching elements SW1 to SW6 in the next calculation cycle and the calculation cycle after that, and calculate the output voltage of the inverter 3 according to the estimation results. Therefore, the output voltage of the inverter 3 can be determined more accurately by taking into account the switching states of the switching elements SW1 to SW6 in the next calculation cycle and the calculation cycle after that.

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

[Embodiment 2]
9 is a block diagram showing a schematic configuration of a motor drive control device 100 according to a second embodiment of the present invention. The motor drive control device 100 differs from the configuration of the first embodiment in that the input voltage Vuvw_out input to the position estimation unit 13 is switched between PWM drive and 180-degree energization one-pulse drive. Therefore, in the following, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted, and only the parts that differ from the first embodiment are described.

As shown in FIG. 9, the motor drive control device 100 has a PWM drive speed control calculation unit 101, a one-pulse drive speed control calculation unit 102, a first output voltage estimator 12, a current control calculation unit 111 (second output voltage estimator), an input voltage selector 112, a position estimator 13, a control signal generator 121, and an analog signal acquisition unit 115. Although not shown, the motor drive control device 100 also performs calculations for each control period synchronized with the carrier frequency used for PWM drive, similar to the motor drive control device 1 of embodiment 1.

The PWM drive speed control calculation unit 101 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 PWM drive speed control calculation unit 101 generates a current command Idq_ref based on the difference between the target speed ωref and the estimated speed ωest. The current command Idq_ref includes a d-axis current command and a q-axis current command. The PWM drive speed control calculation unit 101 has the same configuration as the conventional one, so a detailed description will be omitted.

The one-pulse drive speed control calculation unit 102 has a configuration similar to that of the speed control calculation unit 11 of the first embodiment. Therefore, the one-pulse drive speed control calculation unit 102 calculates the advance angle amount based on the difference between the target speed ωref and the estimated speed ωest. A detailed description of the configuration of the one-pulse drive speed control calculation unit 102 is omitted.

The current control calculation unit 111 estimates the output voltage of the inverter 3 during PWM driving using the current command Idq_ref output from the PWM driving speed control calculation unit 101 and the motor current detection value Idq_ad acquired by the analog signal acquisition unit 115. In detail, the current control calculation unit 111 determines the estimated output voltage Vest_pwm_out (output voltage) of the inverter 3 during PWM driving based on the difference between the current command Idq_ref and the motor current detection value Idq_ad. 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. The configuration of this current control calculation unit 111 is similar to the conventional configuration, so a detailed description will be omitted.

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 calculator 111 according to the drive method of the inverter 3. That is, when the inverter 3 is driven with 180-degree current one-pulse drive, 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 driven by PWM drive, the input voltage selector 112 outputs the estimated output voltage Vest_pwm_out output from the current control calculator 111 to the position estimator 13.

A selection command signal is input to the input voltage selector 112 from a controller (not shown). Specifically, when the inverter 3 is PWM driven, for example, the controller inputs zero as the selection command signal to the input voltage selector 112, and when the inverter 3 is 180-degree current single-pulse driven, for example, the controller inputs one as the selection command signal to the input voltage selector 112. The selection command signal may be a signal other than zero or one.

The position estimation unit 13 uses 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 to determine the estimated speed ωest and estimated position θest of the motor 2. The analog signal acquisition unit 115 converts the three-phase output current Iuvw of the motor into a motor current detection value Idq_ad that includes the d-axis motor current detection value and the q-axis motor current detection value.

The control signal generating unit 121 generates a gate signal for PWM driving and a gate signal for 180-degree energization 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 generating unit 121 outputs a gate signal generated using the estimated output voltage Vest_pwm_out generated by the current control calculation unit 111 to the inverter 3, and when performing 180-degree energization one-pulse driving, the control signal generating unit 121 outputs a gate signal generated using the switching timing time Tsw generated by the switching timing estimating unit 22 to the inverter 3.

In detail, the control signal generating unit 121 has a PWM module 122, an internal timer 41, a gate signal switching unit 42, and a gate signal selector 123.

The PWM module 122 generates a gate signal, which is a PWM signal, using the estimated output voltage Vest_pwm_out output from the current control calculation unit 111. Specifically, the PWM module 122 compares the carrier frequency with the estimated output voltage Vest_pwm_out, and generates and outputs a gate signal that drives the multiple switching elements SW1 to SW6 of the inverter 3 based on the comparison result. 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.

The gate signal selector 123 selects one of the gate signals output from the PWM module 122 and the gate signal switching unit 42 according to the drive method of the inverter 3, and outputs it to the inverter 3. Specifically, when the inverter 3 is PWM driven, the gate signal selector 123 outputs the gate signal output from the PWM module 122 to the inverter 3, and when the inverter 3 is 180-degree current single-pulse driven, the gate signal selector 123 outputs the gate signal output from the gate signal switching unit 42 to the inverter 3.

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 from the controller to the gate signal selector 123 as the selection command signal, and when the inverter 3 is 180-degree current one-pulse driven, one is input from the controller to the gate signal selector 123 as the selection command signal. The selection command signal may be a signal other than zero or one.

As described above, the motor drive control device 100 of this embodiment further includes a current control calculation 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 calculation 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 calculation unit 111 to the position estimator 13 when performing drive control using the PWM signal for the inverter 3.

This allows the input voltage selector 112 to switch the output voltage input to the position estimation unit 13 depending on whether the inverter 3 is driven by PWM drive or 180-degree current single-pulse drive. In other words, when the inverter 3 is driven by PWM drive, the output voltage of the inverter 3 is estimated based on the current command, whereas when the inverter 3 is driven by 180-degree current single-pulse drive, the output voltage of the inverter 3 is estimated based on the voltage phase command.

In this way, the output voltage estimated according to the drive method of the inverter 3 is selected by the input voltage selector 112 according to the drive method of the inverter 3 and input to the position estimation unit 13, so that the position estimation error of the position estimation system can be reduced not only when the inverter 3 is driven by 180-degree current one-pulse drive, but also when it is driven by PWM drive. Therefore, it is possible to stably control PWM drive and 180-degree current one-pulse drive.

Moreover, as described above, by making it possible to switch the drive of the inverter 3 between 180-degree energization one-pulse drive and PWM drive, the inverter 3 can be driven with a more efficient drive method. Therefore, the motor 2 can be driven more efficiently.

Other Embodiments
Although the embodiment of the present invention has been described above, the above-mentioned embodiment is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-mentioned embodiment, and it is possible to carry out the above-mentioned embodiment by appropriately modifying it within the scope of the gist of the present invention.

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

In each of the above embodiments, the control signal generating unit 14, 121 generates a gate signal that switches the switching state 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 generating unit may have a different configuration as long as it is capable of generating a gate signal that realizes 180-degree energization one-pulse drive.

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, but this is not limited thereto, and the present invention may be applied to a control device that controls the drive of an AC motor having multiple phases other than three phases. In other words, the motor 2 may have any configuration as long as it is a synchronous motor.

In the second embodiment, the motor drive control device 100 has an input voltage selector 112 and a gate signal selector 123. However, the motor drive control device may output a gate signal to the inverter from the PWM drive control unit and output an estimated output voltage to the position estimation unit during PWM drive, and may output a gate signal to the inverter from the one-pulse drive control unit and output an estimated output voltage to the position estimation unit during 180-degree energization one-pulse drive.

Figure 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 the first and second embodiments are given the same reference numerals and will not be described.

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

When the PWM drive control unit 201 drives the inverter 3 with PWM, it outputs a gate signal from the PWM module 122 to the inverter 3, and outputs the estimated output voltage Vest_pwm_out from the current control calculation unit 111 to the position estimation unit 13. 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.

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

As described above, when drive control is performed 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 estimator 12 is input to the position estimator 13, while when drive control is performed to the inverter 3 using a PWM signal, the estimated output voltage Vest_pwm_out (output voltage) estimated by the current control calculator 111 is input.

This makes it possible to switch the estimated output voltage input to the position estimation unit 13 depending on whether the inverter 3 is driven by PWM drive or 180-degree current single-pulse drive. That is, when the inverter 3 is driven by PWM drive, the motor drive control device 200 estimates the output voltage of the inverter 3 based on a current command, whereas when the inverter 3 is driven by 180-degree current single-pulse drive, the motor drive control device 200 estimates the output voltage of the inverter 3 based on a voltage phase command.

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, it is possible to reduce the position estimation error of the position estimation system not only when the inverter 3 is driven by 180-degree current one-pulse drive, but also when it is driven by PWM drive. Therefore, it is possible to stably control PWM drive and 180-degree current one-pulse drive.

Moreover, as described above, by making it possible to switch the drive of the inverter 3 between 180-degree energization one-pulse drive and PWM drive, the inverter 3 can be driven with a more efficient drive method. Therefore, the motor 2 can be driven more efficiently.

The present invention can be used in a motor drive control device that controls the drive of a switching circuit having multiple switching elements, thereby controlling the drive of a motor supplied with power from the switching circuit.

1, 100, 200 Motor drive control device 2 Motor 3 Inverter (switching circuit)
11 Speed control calculation 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 calculation unit 24 Switching state estimation unit 25 Voltage calculation unit 41 Internal timer 42 Gate signal switching unit 101 Speed control calculation unit for PWM drive 102 Speed control calculation unit for one-pulse drive 111 Current control calculation unit (second output voltage estimation unit)
112 Input voltage selector 122 PWM module (PWM signal generator)
123 Gate signal selector 201 PWM drive control unit 202 One-pulse drive control unit SW1 to SW6 Switching elements

Claims (4)

1. A motor drive control device that controls driving of a motor supplied with power from a switching circuit by controlling driving of the switching circuit, the motor drive control device comprising:
a first output voltage estimator that estimates an output voltage of the 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;
a control signal generating unit that generates a control signal for causing the switching circuit to output a square wave voltage, using the rotational position estimated by the position estimating unit;
Equipped with
Motor drive control device. 2. The motor drive control device according to claim 1,
The first output voltage estimator is
a switching timing estimation unit that estimates switching timings of the switching states of the plurality of switching elements in the switching circuit based on the voltage phase command;
an estimated output voltage calculation unit that estimates an output voltage of the switching circuit for each predetermined calculation period in accordance with the switching timing estimated by the switching timing estimation unit;
having
Motor drive control device. 3. The motor drive control device according to claim 2,
The estimated output voltage calculation unit
a switching state estimation unit that estimates switching states of the plurality of switching elements in a next calculation cycle and the calculation cycle after that from the switching timing;
a voltage calculation unit that calculates an output voltage of the switching circuit in accordance with the switching states of the plurality of switching elements estimated by the switching state estimation unit;
having
Motor drive control device. 4. The motor drive control device according to claim 1,
a second output voltage estimator that estimates an output voltage of the switching circuit based on a current command;
a PWM signal generating unit that generates a PWM signal for driving the plurality of switching elements in the switching circuit by using the output voltage estimated by the second output voltage estimating unit;
Further equipped with
The output voltage estimated by the first output voltage estimator is input to the position estimator when drive control is performed to output a rectangular wave voltage to the switching circuit, while the output voltage estimated by the second output voltage estimator is input to the position estimator when drive control is performed by the PWM signal to the switching circuit.
Motor drive control device.