JP7189075B2 - MOTOR DRIVE CONTROL APPARATUS AND METHOD, AND MOTOR DRIVE CONTROL SYSTEM - Google Patents

Description

The present invention relates to a motor drive control device and a motor drive control method for controlling the drive of a motor. The present invention also relates to an electric motor drive control system including the electric motor drive control device.

Feedback control using, for example, PI control is often used for drive control of the electric motor. In the speed control, high responsiveness to the target speed is required because it affects the performance of the product using the electric motor. In the feedback control, by setting a large feedback gain, responsiveness can be improved, but so-called overshoot or hunting may occur.

For this reason, model predictive control (MPC) has been proposed for drive control of electric motors because it can achieve higher responsiveness than the conventional feedback control (see, for example, Patent Documents 1 and 2). ). In this model predictive control, the motor is driven and controlled by repeatedly executing the following series of processes in each control cycle. In the series of processes, first, the future behavior of the motor is predicted for each of the plurality of candidate input voltages by using the model of the motor. Next, each prediction result (each behavior of the motor) is evaluated, the prediction result closest to the target is selected, and the motor is driven and controlled at the candidate input voltage that gives this selected prediction result. In such model predictive control, an optimized candidate input voltage can be determined based on the prediction result, so high responsiveness exceeding that of the conventional feedback control can be expected.

JP 2008-228419 A JP 2013-62949 A

By the way, in the model predictive control, as described above, the electric motor is driven and controlled by the candidate input voltage determined by the prediction and the evaluation result for each control cycle. For this reason, the difference in input voltage between each control that is repeatedly executed in the control cycle may become large. That is, when each input voltage is generated by an inverter circuit, the difference between each output voltage of the inverter circuit may become large. Furthermore, in the model predictive control, as described above, the switching operation of the inverter circuit is performed only once in one control cycle. Therefore, the switching cycle of the inverter circuit cannot be set independently of the control cycle of the model predictive control. Due to these factors, a large current ripple occurs.

This current pulsation causes motor loss, output torque pulsation, mechanical vibration and noise, and is desired to be small. Therefore, in order to increase the switching cycle of the inverter circuit, it is desirable to set the control cycle of the model predictive control to be small. It becomes necessary.

The present invention has been made in view of the circumstances described above, and an object of the present invention is to provide an electric motor drive control apparatus and an electric motor drive control method capable of reducing current pulsation when the electric motor is controlled by model predictive control, and the electric motor. An object of the present invention is to provide an electric motor drive control system including a drive control device.

As a result of various studies, the inventors of the present invention have found that the above object can be achieved by the present invention described below. That is, an electric motor drive control device according to one aspect of the present invention is a device for controlling an electric motor driven by the output of an inverter circuit, wherein time-series voltage patterns that can be output by the inverter circuit are set to be different from each other. a voltage pattern generator that generates a plurality of voltage patterns; and a smoother that smoothes each of the plurality of time-series voltage patterns generated by the voltage pattern generator as a smoothed time-series voltage pattern. , for each of the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit, predicting the value of a predetermined physical quantity related to the purpose of controlling the electric motor when the time-series smoothed voltage pattern is input to the electric motor. and a prediction unit that predicts the electric motor as a value, and a prediction with the highest evaluation among the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit. a voltage pattern selection unit that selects a time-series smoothed voltage pattern corresponding to a value; and an inverter control unit that controls the inverter circuit based on the time-series smoothed voltage pattern selected by the voltage pattern selection unit. . Preferably, the motor drive control device is a device for controlling a motor driven by the output of an inverter circuit, and generates a plurality of different time-series voltage patterns that can be output by the inverter circuit. A voltage pattern generation unit that performs generation processing, and a smoothing process that smoothes each of the plurality of time-series voltage patterns generated by the voltage pattern generation unit as a time-series smoothed voltage pattern. and for each of a plurality of time-series smoothed voltage patterns smoothed by the smoothing unit, the control purpose of the electric motor when the time-series smoothed voltage pattern is input to the electric motor a prediction unit that performs prediction processing for predicting a value of a predetermined physical quantity as a prediction value; and the electric motor predicted by the prediction unit from among a plurality of time-series smoothed voltage patterns smoothed by the smoothing unit a voltage pattern selection unit that performs a voltage pattern selection process for selecting a time-series smoothed voltage pattern corresponding to the predicted value with the highest evaluation among the predicted values of each; an inverter control unit that performs a PWM inverter control process for controlling the inverter circuit based on a smoothed voltage pattern; the voltage pattern generation process, the prediction process, the smoothing process, the voltage pattern selection process, and the PWM inverter control; and a repeat control unit that causes the voltage pattern generation unit, the prediction unit, the smoothing unit, the voltage pattern selection unit, and the PWM inverter control unit to repeatedly perform processing at a predetermined control cycle.

In such a motor drive control device, each of the plurality of time-series voltage patterns generated by the voltage pattern generation unit is smoothed by the smoothing unit, and among the smoothed multiple time-series smoothed voltage patterns, Since the smoothed voltage pattern selected from is used, it is possible to reduce the difference in input voltage between each control that is repeatedly executed in the control cycle, so that the current ripple can be reduced.

In another aspect, the electric motor drive control device described above further includes a determination unit that determines whether or not the smoothed voltage pattern can be output by the inverter circuit, and the smoothing unit determines whether or not the determination result of the determination unit is generating the smoothed voltage pattern based on the

Since such a motor drive control device generates the smoothed voltage pattern based on the determination result of whether or not the inverter circuit can output the smoothed voltage pattern, the motor can be stably driven.

In another aspect of the above-described electric motor drive control device, the smoothing unit converts each of the plurality of time-series voltage patterns generated by the voltage pattern generation unit into time-series voltage patterns. A digital low-pass filter section for smoothing a smoothed voltage pattern, and a filter coefficient control section for controlling filter coefficients of the digital low-pass filter section so as to achieve a predetermined smoothness representing the degree of smoothing.

Since such a motor drive control device includes a filter coefficient control section, smoothness can be adjusted.

In another aspect, in the above-described electric motor drive control device, the predetermined physical quantity related to the purpose of controlling the electric motor is rotational speed.

According to this, it is possible to provide a motor drive controller capable of speed control.

In another aspect of the above-described motor drive control device, the predetermined physical quantity related to the purpose of controlling the motor is drive current.

According to this, it is possible to provide an electric motor drive controller capable of torque control by drive current control.

In another aspect, the above-described electric motor drive control device further includes a current acquisition unit that acquires a current flowing to the electric motor, and a rotation speed acquisition unit that acquires a rotation speed of the electric motor, wherein the determination unit Whether the inverter circuit can output the smoothed voltage pattern based on the current acquired by the current acquisition unit, the rotation speed acquired by the rotation speed acquisition unit, the maximum voltage supplied to the inverter circuit, and the characteristic parameters of the electric motor determine whether or not

Whether or not such a motor drive control device can output the smoothed voltage pattern from the inverter circuit based on the acquired current and rotational speed (driving state of the motor), and the maximum voltage and characteristic parameters obtained in advance. can be determined in real time from the drive state of the electric motor.

A motor drive control method according to another aspect of the present invention is a method of controlling a motor driven by the output of an inverter circuit, wherein time-series voltage patterns that can be output by the inverter circuit are set to be different from each other. a voltage pattern generation step of generating a plurality of voltage patterns; and a smoothing step of smoothing each of the plurality of time-series voltage patterns generated in the voltage pattern generation step as a time-series smoothed voltage pattern. , for each of the plurality of time-series smoothed voltage patterns smoothed in the smoothing step, predicting the value of a predetermined physical quantity related to the purpose of controlling the electric motor when the time-series smoothed voltage pattern is input to the electric motor. a prediction step of predicting as a value, and prediction of the highest evaluation among the plurality of time-series smoothed voltage patterns smoothed in the smoothing step among the predicted values of the electric motor predicted in the prediction step. a voltage pattern selection step of selecting a time-series smoothed voltage pattern corresponding to a value; and an inverter control step of controlling the inverter circuit based on the time-series smoothed voltage pattern selected in the voltage pattern selection step. .

In such a motor drive control method, each of the plurality of time-series voltage patterns generated in the voltage pattern generation step is smoothed in the smoothing step, and among the smoothed time-series smoothed voltage patterns, Since the smoothed voltage pattern selected from is used, it is possible to reduce the difference in input voltage between each control that is repeatedly executed in the control cycle, so that the current ripple can be reduced.

In another aspect, the motor drive control method described above further comprises a determining step of determining whether or not the smoothed voltage pattern can be output by the inverter circuit, wherein the smoothing step is based on the determination result of the determining step generating the smoothed voltage pattern based on the

In such a motor drive control method, the smoothed voltage pattern is generated based on the determination result of whether or not the inverter circuit can output the smoothed voltage pattern, so the motor can be stably driven.

An electric motor drive control system according to another aspect of the present invention includes an electric motor, an inverter circuit that drives the electric motor, and an electric motor drive control unit that controls the electric motor by controlling the inverter circuit. The drive control unit is any one of the motor drive control devices described above.

According to this, it is possible to provide an electric motor drive control system including any one of the electric motor drive control devices described above. Since such a motor drive control system includes any one of the motor drive control devices described above, it is possible to reduce current pulsation when driving and controlling the motor by model predictive control.

The electric motor drive control device and the electric motor drive control method according to the present invention can reduce current pulsation when the electric motor is controlled by model predictive control. According to the present invention, a motor drive control system having this motor drive control device can be provided.

1 is a block diagram showing the configuration of an electric motor drive control system in an embodiment; FIG. 2 is a block diagram showing the configuration of an MPC control section in the motor drive control system of the first embodiment shown in FIG. 1; FIG. 3 is a circuit diagram showing the configuration of an inverter circuit in the motor drive control system; FIG. 4 is a vector diagram showing voltages that can be output from the inverter circuit; FIG. It is a figure for demonstrating an example of the time-sequential voltage pattern which can be output from the said inverter circuit. 4 is a flowchart showing operations in the electric motor drive control system; In the first embodiment, it is a diagram showing a simulation result of speed control. 2 is a block diagram showing the configuration of an MPC control section in the motor drive control system of the second embodiment shown in FIG. 1; FIG. In the second embodiment, it is a diagram showing a simulation result of speed control. FIG. 10 is a diagram showing speed control simulation results for different degrees of smoothness of speed deviation and current deviation in a voltage range that can be output by an inverter circuit;

One or more embodiments of the invention are described below with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments. It should be noted that the configurations denoted by the same reference numerals in each figure indicate the same configurations, and the description thereof will be omitted as appropriate. In the present specification, reference numerals with suffixes omitted are used when referring to generically, and reference numerals with suffixes are used when referring to individual configurations.

A motor drive control system according to an embodiment is a system that controls and drives a motor, and includes a motor drive control device that controls the motor that is driven by the output of an inverter circuit. In this embodiment, the motor drive control system S controls and drives the motor by vector control using model predictive control. Hereinafter, such an electric motor drive system will be described more specifically in first and second embodiments.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of an electric motor drive control system according to an embodiment. FIG. 1 shows each configuration of the electric motor drive control system in the first and second embodiments, and each configuration common to the electric motor drive systems Sa and Sb in the first and second embodiments has no suffix. , the configuration of the electric motor drive system Sa in the first embodiment is illustrated by adding the suffix “a”, and the configuration of the electric motor drive system Sb in the second embodiment is illustrated by adding the suffix “b” is illustrated by FIG. 2 is a block diagram showing the configuration of the MPC control section in the motor drive control system of the first embodiment shown in FIG. 1. As shown in FIG. FIG. 3 is a circuit diagram showing the configuration of an inverter circuit in the motor drive control system. FIG. 4 is a vector diagram showing voltages that can be output by the inverter circuit. FIG. 5 is a diagram for explaining an example of a time-series voltage pattern that can be output from the inverter circuit.

The motor drive control system Sa in the first embodiment includes, for example, as shown in FIG. , a three-phase to two-phase converter CV2, a rotational speed processor RSC, a current measuring section CS, and a rotation angle measuring section VS.

The electric motor M is a motor connected to the inverter circuit IV and driven by the AC output of the inverter circuit IV. For example, the electric motor M is a synchronous motor driven by three-phase AC power of U-phase, V-phase and W-phase output from the inverter circuit IV. magnet synchronous motor, PMSM). The electric motor M is not limited to this, and may be, for example, an induction motor (IM) or another type such as an SR motor (Switched Reluctance motor (SRM)).

The PWM modulator PW is a circuit that outputs a rectangular wave with a variable pulse width, and the inverter circuit IV is a circuit that converts DC power to AC power. In this embodiment, the PWM modulator PW and the inverter circuit IV constitutes a so-called three-phase PWM inverter motor driver that drives a motor with three-phase AC power. These PWM modulator PW and inverter circuit IV are connected to a model predictive controller MCa via a two-to-three phase converter CV1, and convert DC power from a DC power supply Vdc to a predetermined Convert to AC power of frequency. More specifically, the PWM modulator PW is a circuit that outputs a rectangular wave having a frequency and a pulse width according to the control of the model predictive controller MCa to the inverter circuit IV as a control signal (IV control signal), which will be described later. The inverter circuit IV is a circuit that is connected to the PWM modulator PW and converts the DC power of the DC power supply Vdc into AC power of a predetermined frequency according to the IV control signal from the PWM modulator PW. For example, as shown in FIG. 3, the inverter circuit IV includes three sets Tr1, Tr4; Tr2, Tr5; Prepare. More specifically, the inverter circuit IV includes six first through sixth switches Tr1 through Tr6. These first to sixth switching elements Tr1 to Tr6 are power semiconductor elements, such as insulated gate bipolar transistors (IGBTs), which have switching functions to turn on and off. One terminal (for example, each collector terminal) of each of the first to third switching elements Tr1 to Tr3 is connected to one terminal of the DC power supply Vdc. The other terminal (for example, emitter terminal) of the first switching element Tr1 is connected to one terminal (for example, each collector terminal) of the fourth switching element Tr4. The other terminal (for example, emitter terminal) of the second switching element Tr2 is connected to one terminal (for example, each collector terminal) of the fifth switching element Tr5. The other terminal (for example, the emitter terminal) of the third switching element Tr3 is connected to one terminal (for example, each collector terminal) of the sixth switching element Tr6. The other terminals (for example, emitter terminals) of the fourth to sixth switching elements Tr4 to Tr6 are connected to the other terminal of the DC power supply Vdc. Control terminals (for example, gate terminals) to which IV control signals for turning on/off the switching elements Tr are input in the first to sixth switching elements Tr1 to Tr6 are connected to the PWM modulator PW. Diodes D1 to D6 having anode terminals connected to the other terminals are connected between the one terminals and the other terminals of the first to sixth switching elements Tr1 to Tr6, respectively. A first connection point that connects the first switching element Tr1 and the fourth switching element Tr4 is connected to an input terminal that outputs a U-phase alternating current and connects the U-phase of the electric motor M, for example. A second connection point connecting the second switching element Tr2 and the fifth switching element Tr5 outputs, for example, a V-phase alternating current and is connected to an input terminal to which the V-phase of the electric motor M is connected. A third connection point that connects the third switching element Tr3 and the sixth switching element Tr6 is connected to an input terminal that outputs a W-phase AC current and connects the W-phase of the electric motor M, for example. In such a configuration, the inverter circuit IV is a so-called two-level three-phase inverter circuit, and the switching elements Tr1, Tr2, and Tr3 on one side of each group and the switching elements Tr4, Tr5, and Tr6 on the other side are switched in opposite directions to each other. Control is performed according to the IV control signal from the PWM modulator PW so that when one is on, the other is off, and when one is off, the other is on. It converts the DC power and outputs AC current of three phases of U-phase, V-phase and W-phase to the electric motor M.

The current measurement unit CS is connected to the three-to-two phase conversion unit CV2, and measures the current flowing from the inverter circuit IV to the electric motor M, in this embodiment, the U-phase current, the V-phase current, and the W-phase current. This device outputs the measurement result to the three-to-two phase converter CV2. The current measuring unit CS is configured with an AC ammeter, for example.

The rotation angle measurement unit VS is connected to the two-to-three-phase conversion unit CV1, the three-to-two phase conversion unit CV2, and the rotation speed processing unit RSC, respectively, measures the magnetic pole position in the electric motor M in terms of angles, and obtains the measurement result (rotation angle , electrical angle (=mechanical angle/number of pole pairs of motor M)) to two-to-three-phase converter CV1, three-to-two phase converter CV2, and rotation speed processor RSC. The rotation angle measurement unit VS is configured including, for example, a rotary encoder (pulse generator), a Hall IC, and the like. In the sensorless case, the rotation angle measurement unit VS may use a model of the electric motor M to obtain the rotation angle of the electric motor M from the current and voltage.

The two-to-three-phase converter CV1 is connected to the model prediction controller MCa, and receives the measurement result (rotation angle) input from the rotation angle measurement unit VS and the smoothed voltage pattern obtained by the model prediction controller MCa as described later. from the target voltages v d ^* , v _q ^* based on the target voltages v _d *, v q *, PWM modulation so that target U-phase current, V-phase current, and W-phase current corresponding to the target voltages v _d ^* , v _q ^* are output from the inverter circuit IV A control signal (PWM control signal) for controlling the modulator PW is obtained, and this PWM control signal is output to the PWM modulator PW.

The three-to-two phase conversion unit CV2 is connected to the model predictive control unit MCa, and receives measurement results (U-phase current, V-phase current, and W-phase current) input from the current measurement unit CS and input from the rotation angle measurement unit VS. From the measured result (rotational angle), the excitation current (d-axis current) i _d and the torque component current (q-axis current) i _q are obtained by the so-called Clarke transformation and Park transformation, and the determined d It outputs the axis current id and the _q -axis current _iq to the model prediction controller MC.

The rotation speed processing unit RSC is connected to the model predictive control unit MCa, obtains the rotation speed ω _m of the electric motor M from the measurement result (rotation angle) input from the rotation angle measurement unit VS, and calculates the obtained rotation speed ω _m is output to the model predictive control unit MCa. For example, the rotation speed _ωm can be obtained by time-differentiating the rotation angle _θe measured by the rotation angle measuring unit VS and multiplying it by the reciprocal of the number of pole pairs p of the motor M.

The model predictive control unit MCa drives and controls the electric motor M via the PWM modulator PW and the inverter circuit IV by vector control using model predictive control. More specifically, for example, as shown in FIG. and a PWM inverter control unit 16 .

The control section 11 controls each section of the electric motor drive control system Sa according to the function of each section, and controls the entire electric motor drive control system Sa.

The voltage pattern generator 12 generates a plurality of different time-series voltage patterns that can be output by the inverter circuit IV. That is, the voltage pattern generation unit 12 performs a voltage pattern generation process of generating a plurality of different time-series voltage patterns that can be output by the inverter circuit IV. In this embodiment, the inverter circuit IV is a two-level ^three -phase inverter as described above. = 8 different voltages can be output. The voltage vector V ₀ is obtained when the first to third switching elements Tr1 to Tr3 are off, the fourth to sixth switching elements Tr4 to Tr6 are on, and the electric motor M is not supplied with power (V ₀ =(0 , 0, 0)). The voltage vector V ₇ is obtained when the first to third switching elements Tr1 to Tr3 are on, the fourth to sixth switching elements Tr4 to Tr6 are off, and the electric motor M is not supplied with power (V ₇ =(0, 0 , 0)). The time-series voltage pattern is determined by a prediction horizon, which is the number of control cycles to be predicted, and a control horizon, which is the number of control cycles in which the voltage, which is the control input, is variable. Therefore, in the model predictive control unit MCa, the numerical value of the prediction horizon and the numerical value of the control horizon are appropriately set in advance according to the specifications of the model predictive control, etc., and the voltage pattern generation unit 12 outputs from the inverter circuit IV A plurality of time-series voltage patterns that are different from each other are generated according to the possible voltages (8 patterns in the above description), the numerical value of the prediction horizon, and the numerical value of the control horizon. FIG. 5 shows, as an example, a tree diagram of all time-series voltage patterns that can be output from the inverter circuit IV when the prediction horizon _Np is 2 and the control horizon _Nc is 1. . In FIG. 5, the predicted horizon _Np is 2 for the voltage in the current Nth control, so the voltage in the next (N+1)th control and the voltage in the next (N+2)th control are Since the predicted control horizon _Nc is 1, all the time-series voltage patterns that can be output from the inverter circuit IV are changed from the voltage in the current Nth control to the voltage in the next (N+1)th control to 8 voltages V ₀ to V ₈ , and in the next (N+2)-th control, each voltage V ₀ to V ₈ is divided into 8 sets of time series maintained at the voltages V ₀ to V ₈ respectively. voltage pattern. As another example, when the prediction horizon is 2 and the control horizon is 2, the prediction horizon is 2 for the voltage in the current Nth control, so in the next (N+1)th control Since the voltage and the voltage in the next (N+2)th control are predicted, and the control horizon is 2, all the time-series voltage patterns that can be output by the inverter circuit IV are the (N+1)th control and Each of the (N+2)-th control is branched into 8 voltages V ₀ to V ₈ , resulting in 64 sets of time-series voltage patterns.

The smoothing unit 13a smoothes each of the plurality of time-series voltage patterns generated by the voltage pattern generation unit 12 as a time-series smoothed voltage pattern. That is, the smoothing unit 13a performs a smoothing process of smoothing each of the time-series voltage patterns generated by the voltage pattern generation unit 12 as a time-series smoothed voltage pattern. . More specifically, in the present embodiment, the smoothing unit 13a smoothes the time-series voltage pattern by filtering the time-series voltage pattern with a low-pass filter. More specifically, when the model predictive control unit MCa repeatedly controls the electric motor M at each predetermined control cycle set in advance, the voltage vector on the dq axis (rotational coordinate system) in the k-th control is v _dq (k ), the smoothed voltage vector is v _dqs (k), and the smoothness for adjusting the degree of smoothing is Ka as a parameter. The time-series voltage pattern is smoothed by the following equation (1). In Equation 1, the smoothed voltage vector v _dqs (k) in the k-th control is the smoothed voltage vector v _dqs (k-1) and k The voltage vector in the th control is obtained by weighted averaging v _dq (k) weighted by the smoothness Ka. The smoothness Ka is appropriately set in advance within a range from 0 to 1 (0≦Ka≦1). As the smoothness Ka approaches 1, the smoothed voltage vector v _dqs (k−1) in the (k−1)th control is emphasized, and the smoothed voltage vector v _dqs (k ), the ratio of the smoothed voltage vector v _dqs (k-1) in the (k-1)th control increases, and conversely, as the smoothness Ka approaches 0, in the kth control The voltage vector v _dq (k) is emphasized, and the ratio of the voltage vector v _dq (k) in the k-th control to the smoothed voltage vector v _dqs (k) in the k-th control increases. Note that the voltage vector v _dq (k) is [v _d (k), v _q (k)] ^T (v _dq (k)=[v _d (k), v _q (k)] ^T ).

Here, the voltage value actually output from the inverter circuit IV in the control of the previous control cycle is used for v _dqs (0) of the first term on the right side of Equation 1 when k=1.

In the above example, in the current k-th control, smoothing is performed on [v _dq (k+1), v _dq (k+2)] up to two control cycles ahead of eight patterns generated by the voltage pattern generation unit 12. [v _dqs (k+1), v _dqs (k+2)] up to two control cycles ahead are obtained in eight ways by the unit 13a.

For each of the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit 13a, the prediction unit 14 calculates a predetermined value related to the purpose of controlling the electric motor M when the time-series smoothed voltage pattern is input to the electric motor M. It predicts the value of a physical quantity as a predicted value. That is, for each of the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit 13a, the value of a predetermined physical quantity related to the control purpose of the electric motor M when the time-series smoothed voltage pattern is input to the electric motor M as a predicted value. More specifically, in the present embodiment, the predetermined physical quantity _related to the purpose of controlling the electric motor M is the rotation speed. Then, the q-axis current _iq is obtained by the following equation 3 using the smoothed _q -axis voltage _vqs . Then, the prediction unit 14 obtains the torque T _e by the following equation 4, and obtains the rotation speed ω _m by the following equation 5 using the obtained torque T _e .

where i _d (k) is the d-axis current in the k-th control, i _q (k) is the q-axis current in the k-th control, L _d is the d-axis inductance, L _q is the q-axis inductance. In this embodiment, since the motor M is a permanent magnet type synchronous motor, L _d =L _q =L. T _s is the control period, R is the winding resistance of the motor M, ω _m (k) is the measured rotation speed (actual rotation speed) in the k-th control, and p is , is the number of pole pairs in the electric motor M, Ψ is the flux linkage of the permanent magnet in the electric motor M, J is the moment of inertia of the rotor in the electric motor M, and D is the dynamic frictional resistance of the rotor in the electric motor M. be. In the case of the k-th control, (k+1), (k+2), (k+3), . . . represent predicted values.

In the above example, in the current k-th control, the predicting unit 14 _{performs eight types} of two control [i _dq (k+1), i _dq (k+2)] up to two control cycles ahead and [ω _m (k+1), ω _m (k+2)] up to two control cycles ahead are obtained as prediction values. Note that the current vector i _dq (k) is [ _id (k), i _q (k)] ^T (i _dq (k)=[ _id (k), i _q (k)] ^T ).

The voltage pattern selection unit 15 selects the highest evaluation prediction value among the prediction values of the electric motor M predicted by the prediction unit 14 from among the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit 13a. to select a time-series smoothed voltage pattern corresponding to . That is, the voltage pattern selection unit 15 selects the highest evaluation value among the predicted values of the electric motor M predicted by the prediction unit 14 from among the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit 13a. A voltage pattern selection process is performed to select a time-series smoothed voltage pattern corresponding to the predicted value. More specifically, the voltage pattern selection unit 15 selects the electric current prediction value [i _dq ( k+1), i _dq (k+2)] and rotational speed prediction values [ω _m (k+1), ω _m (k+2)], for example, in the evaluation formula g of the following equation 6, to obtain the time-series smoothed voltage pattern Quantitatively evaluated, the highest evaluated current predicted value [i _dq (k+1), i _dq (k+2)] and rotational speed predicted value [ω _m (k+1) from among the plurality of time-series smoothed voltage patterns , ω _m (k+2)]. In the evaluation formula g of Formula 6, the smaller the evaluation value, the higher the evaluation. Therefore, among the plurality of time-series smoothed voltage patterns, the predicted current values [i _dq (k+1), i _dq (k+2)] and the predicted rotational speed values [ω _m (k+1), ω _m (k+2)] is selected as the optimum time-series smoothed voltage pattern. Note that the rotational speed ω _m ^* of the target value for the control purpose is input from the outside to the model predictive control unit MCa and set.

Since the evaluation formula g of the above formula 6 is important for speed control, the speed deviation is set as the first term, and in the case of a permanent magnet synchronous motor, in order to prevent unnecessary power supply, it contributes to the generation of torque. Since it is important to keep the _d -axis current id at 0, the current deviation is defined as the second term, and these first and second terms are linearly combined with coefficients a and b. . Therefore, the coefficients a and b are appropriately determined in advance according to the relative importance of the first term and the second term. In other words, the coefficients a and b can be used to adjust the relative importance of the first term and the second term. That is, in the control of the motor M, when the speed deviation is relatively more important than the current deviation, the coefficient a is set larger than the coefficient b (a>b). If the deviation is relatively more important than the speed deviation, the factor b is set greater than the factor a (b>a), and if both are equally important, the factor a is equal to the factor b. is set (a=b).

The PWM inverter control section 16 controls the inverter circuit IV based on the time-series smoothed voltage pattern selected by the voltage pattern selection section 15 . That is, the PWM inverter control unit 16 performs PWM inverter control processing for controlling the inverter circuit IV based on the time-series smoothed voltage pattern selected by the voltage pattern selection unit 15 . More specifically, in the present embodiment, the PWM inverter control unit 16 controls the next (k+1) in the time-series smoothed voltage pattern selected by the voltage pattern selection unit 15 when the current control is k-th control. With the d-axis voltage v _d (k+1) and the q-axis voltage v _q (k+1) in the second control as the d-axis target voltage v _d ^* and the q-axis target voltage v _q ^* , respectively, the target voltages v _d ^* , v A PWM control signal is generated by the two-to-three-phase converter CV1 and PWM-modulated with this PWM control signal so that the target U-phase current, V-phase current and W-phase current corresponding to _q ^* are output from the inverter circuit IV. The device PW is caused to generate an IV control signal, and the generated IV control signal is output from the PWM modulator PW to the inverter circuit IV.

Then, the control unit 11 performs the voltage pattern generation processing, the smoothing processing, the prediction processing, the voltage pattern selection processing, and the inverter control processing in a voltage pattern generation unit 12, a smoothing unit 13a, a prediction unit 14, a voltage pattern generation unit 12, a smoothing unit 13a, a prediction unit 14, a voltage The pattern selection unit 15 and the PWM inverter control unit 16 are caused to repeatedly perform the control at a predetermined control cycle.

The model predictive controller MCa, the two-to-three-phase converter CV1, the three-to-two phase converter CV2, and the rotation speed processor RSC are configured with a CPU (Central Processing Unit), a memory, and peripheral circuits thereof. A control unit 11, a voltage pattern generation unit 12, a smoothing unit 13a, a prediction unit 14, a voltage pattern selection unit 15, a PWM inverter control unit 16, and a two-phase three-phase conversion in the model prediction control unit MCa. Part CV1, three-to-two phase conversion part CV2, and rotation speed processing part RSC are functionally configured in the CPU by executing a predetermined program.

Next, the operation of this embodiment will be described. FIG. 6 is a flow chart showing the operation of the motor drive control system. FIG. 6 shows each process of the electric motor drive control system in the first and second embodiments, and each process common to the electric motor drive systems Sa and Sb in the first and second embodiments is , the processing of the electric motor drive system Sa in the first embodiment is illustrated by adding the suffix “a”, and the processing of the electric motor drive system Sb in the second embodiment is illustrated by adding the suffix “b” is illustrated by FIG. 7 is a diagram showing simulation results of speed control in the first embodiment.

In the electric motor drive control system Sa of the first embodiment, when the power is turned on, the necessary parts are initialized and started to operate. Then, for example, by executing a program, the CPU is functionally configured with a model prediction control section MCa, a two-to-three-phase conversion section CV1, a three-to-two-phase conversion section CV2, and a rotational speed processing section RSC. The control unit MCa includes a control unit 11, a voltage pattern generation unit 12, a smoothing unit 13a, a prediction unit 14, a voltage pattern selection unit 15, and a PWM inverter control unit 16 functionally.

6 are repeatedly executed by the control unit 11 at predetermined control cycles until the driving of the electric motor M is stopped.

In FIG. 6, first, at this time (k-th), the current value of each phase measured by the current measurement unit CS is acquired, and the rotation angle value measured by the rotation angle measurement unit VS is acquired (S11). . The current measurement unit CS outputs the acquired current values of each phase to the three-to-two phase conversion unit CV2, and the rotation angle measurement unit VS outputs the acquired rotation angle values to the two-to-three phase conversion unit CV1, Output to the three-to-two phase converter CV2 and the rotational speed processor RSC.

Subsequently, the three-to-two-phase conversion unit CV2 obtains the d-axis current i _d and the q-axis current i _q from the current value and the rotation angle value of each phase obtained in step S11, and the obtained d-axis current i The _d- and _q -axis currents iq are output to the model predictive control unit MCa, and the rotational speed processing unit RSC obtains the rotational speed _ωm from the current value and the rotational angle value of each phase obtained in step S11. The rotational speed ω _m thus obtained is output to the model predictive control unit MCa (S12).

Subsequently, the voltage pattern generation unit 12 causes the model prediction control unit MCa to generate different time-series voltage patterns that can be output from the inverter circuit IV according to the preset prediction horizon value and control horizon value. (S13, voltage pattern generation process).

Subsequently, the model predictive control unit MCa converts each of the time-series voltage patterns generated by the voltage pattern generation unit 12 in step S12 into time-series smoothed voltages by the smoothing unit 13a. It is smoothed as a pattern (S14a, smoothing process).

Subsequently, the model predictive control unit MCa inputs the time-series smoothed voltage patterns to the electric motor M for each of the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit 13a in the processing S14a by the prediction unit 14. A value of a predetermined physical quantity related to the control purpose of the electric motor M in the case where it is determined is predicted as a predicted value (S15, prediction processing). More specifically, in this embodiment, the prediction unit 14 obtains the _d -axis current id by the following equation 2, the _q -axis current iq by the following equation 3, the torque _Te by the following equation 4, A rotation speed prediction value ω _m is obtained by the following equation (5).

Subsequently, the voltage pattern selection unit 15 selects the time-series smoothed voltage patterns smoothed by the smoothing unit 13a in the process S14a by the model prediction control unit MCa. A time-series smoothed voltage pattern corresponding to the predicted value with the highest evaluation among the predicted values of the electric motor M obtained is selected (S16, voltage pattern selection process).

Subsequently, the model predictive control unit MC causes the PWM inverter control unit 16 to control the PWM modulator PW and the inverter circuit IV based on the time-series smoothed voltage pattern selected by the voltage pattern selection unit 15 in step S16. to drive the electric motor M (S17, PWM inverter control process).

In this way, the electric motor M is controlled and driven by the model predictive control so that the rotational speed ω _m ^* is the target value for the control purpose.

Simulations (numerical experiments) verified the effects of the motor drive control system Sa, the motor drive control device, and the motor drive control method implemented therein in this embodiment. FIG. 7 shows the simulation result of the speed control of the one embodiment together with the comparative example. 7A, 7B and 7C show simulation results of speed control by the motor drive control system Sa in the first embodiment, FIG. 7A shows the rotation speed, FIG. 7B shows the _d -axis current id, FIG. 7C shows the q-axis current i _q . 7D, 7E and 7F show simulation results of speed control according to the comparative example, FIG. 7D shows the rotational speed, FIG. 7E shows the _d -axis current id, and FIG. 7F shows the q-axis current i _q is shown. Each horizontal axis in FIGS. 7A to 7F is elapsed time, each vertical axis in FIGS. 7A and 7D is rotational speed, and each vertical axis in FIGS. 7B and 7E is _d -axis current id. , 7C and 7F is the _q -axis current iq. The comparative example is the same as the above example, except that the voltage patterns generated by the voltage pattern generator 12 are used as they are without being smoothed. In the example and the comparative example, the control period of the model predictive control is 100 μsec, and the carrier frequency is 10 kHz. The smoothness Ka in the above example was set to 0.9. As can be seen from FIGS. 7E and 7F, current ripple occurs in the _d -axis current id and the _q -axis current iq in the comparative example. , the current ripples of the _d -axis current id and the _q -axis current iq are reduced. As can be seen from FIGS. 7A and 7D, there is no difference in target speed follow-up performance between the embodiment and the comparative example, and control responsiveness is maintained. In FIGS. 7A and 7D, dashed lines indicate target values (reference values), and solid lines indicate measured values.

As described above, the motor drive control system Sa, the motor drive control device, and the motor drive control method implemented therein according to the present embodiment smooth each of a plurality of time-series voltage patterns generated as candidate input voltages. Since a smoothed voltage pattern selected from among a plurality of smoothed voltage patterns is used, it is possible to reduce the difference in input voltage between each control that is repeatedly executed in the control cycle, thereby reducing current pulsation.

According to this embodiment, it is possible to provide a motor drive control system Sa, a motor drive control device, and a motor drive control method capable of speed control.

Next, another embodiment will be described.
(Second embodiment)
If the smoothed voltage pattern generated by the smoothing unit 13a and selected by the voltage pattern selecting unit 15 can be output by the inverter circuit IV, the inverter circuit IV can supply AC power to the electric motor M using the smoothed voltage pattern. The electric motor drive control system Sa in the embodiment can drive the electric motor M stably. However, since the voltage pattern generator 12 generates a plurality of time-series voltage patterns different from each other according to the numerical value of the prediction horizon and the numerical value of the control horizon, the voltage pattern exceeds the voltage range that can be generated by the inverter circuit IV. can occur. That is, the voltage pattern may become an overmodulation region where the IV control signal of the PWM modulator PW and the output of the inverter circuit IV do not match. In such a case, the electric motor drive control system Sa cannot drive the electric motor M stably. Therefore, in the second embodiment, such a smoothed voltage pattern is suppressed, and the electric motor M can be driven more stably.

FIG. 8 is a block diagram showing the configuration of the MPC control section in the motor drive control system of the second embodiment shown in FIG. 1. As shown in FIG. For example, as shown in FIG. 1, the motor drive control system Sb in the second embodiment includes a motor M, an inverter circuit IV, a PWM modulator PW, a two-to-three-phase converter CV1, and a model prediction It includes a control unit MCb, a three-to-two phase conversion unit CV2, a rotation speed processing unit RSC, a current measurement unit CS, and a rotation angle measurement unit VS. That is, the motor drive control system Sb of the second embodiment includes a model predictive controller MCb instead of the model predictive controller MCa of the motor drive control system Sa of the first embodiment. Therefore, the electric motor M, the inverter circuit IV, the PWM modulator PW, the two-to-three-phase converter CV1, the three-to-two phase converter CV2, the rotational speed processor RSC, and the current measurement in the electric motor drive control system Sb of the second embodiment The part CS and the rotation angle measuring part VS are respectively the electric motor M, the inverter circuit IV, the PWM modulator PW, the two-to-three phase converter CV1, and the three-to-two phase converter CV2 in the electric motor drive control system Sa of the first embodiment. , the rotation speed processing unit RSC, the current measurement unit CS, and the rotation angle measurement unit VS, the description thereof will be omitted.

The model predictive control unit MCb drives and controls the electric motor M via the PWM modulator PW and the inverter circuit IV by vector control using model predictive control. More specifically, in the second embodiment, the model prediction controller MCb includes, for example, a controller 11, a voltage pattern generator 12, a smoother 13b, and a predictor 14 as shown in FIG. , a voltage pattern selection unit 15 , a PWM inverter control unit 16 , and a determination unit 17 . That is, the model predictive control unit MCb in the second embodiment includes a smoothing unit 13b instead of the smoothing unit 13a in the model predictive control unit MCa in the first embodiment, and further includes a determination unit 17. FIG. For this reason, the control unit 11, the voltage pattern generation unit 12, the prediction unit 14, the voltage pattern selection unit 15, and the PWM inverter control unit 16 in the model prediction control unit MCb of the second embodiment are the model prediction of the first embodiment. Since it is the same as the control section 11, the voltage pattern generation section 12, the prediction section 14, the voltage pattern selection section 15 and the PWM inverter control section 16 in the control section MCa, the description thereof will be omitted.

The determination unit 17 determines whether or not the smoothed voltage pattern can be output from the inverter circuit IV. That is, the determination unit 17 performs determination processing for determining whether or not the smoothed voltage pattern can be output by the inverter circuit IV. The determination unit 17 determines whether the smoothed voltage pattern obtained by the smoothing unit 13b is equal to or less than the maximum voltage of the power supply Vdc, thereby determining whether the smoothed voltage pattern can be output from the inverter circuit IV. However, in this embodiment, the determination unit 17 determines the current flowing to the electric motor M, the rotation speed of the electric motor M, the maximum voltage supplied to the inverter circuit IV (the maximum output voltage of the power supply Vdc that supplies power to the inverter circuit IV), and the electric motor Based on the characteristic parameter of M, it is determined whether or not the smoothed voltage pattern can be output by the inverter circuit IV. More specifically, the determination unit 17 determines that the q-axis current iq obtained by the current measurement unit CS and the three-to-two-phase conversion unit CV2 is equal to or less than the threshold ( _q -axis current threshold) _iqlim given by the following equation 7. If the determined q-axis current iq is equal to or less than the _q -axis current threshold _iqlim , it is determined that output is possible, and the determined q-axis current iq exceeds the _q -axis current threshold _iqlim If it is not equal to or below (exceeds the q-axis current threshold i _qlim ), it is determined that output is not possible (output is not possible). The determination unit 17 notifies the smoothing unit 13b of this determination result.

Here, ω _m is the actual rotation speed obtained by the rotation angle measurement unit VS and the rotation speed processing unit RSC. The characteristic parameters of the electric motor M are the parameters that determine the specifications of the electric motor M. In Equation 7, they are the winding resistance R, the q-axis inductance L _q , the magnetic flux linkage Ψ of the permanent magnet, and the number of pole pairs p. As described above, the pole logarithm _p is used when the rotation speed processing unit RSC obtains the rotation speed ωm from the rotation angle _θe measured by the rotation angle measurement unit VS.

This expression 7 is derived from the inequality of the following expression 8. In this inequality 8, the left side is the maximum output voltage of the inverter circuit IV that can be output by the inverter circuit IV, which is determined by the maximum voltage supplied to the inverter circuit IV (the maximum output voltage of the power supply Vdc that supplies power to the inverter circuit IV). , the right side thereof is the voltage required to maintain the torque and rotation speed currently output by the electric motor M. When this inequality 8 holds, the voltage supplied from the power supply Vdc is equal to or lower than the maximum output voltage of the power supply Vdc, and the inverter circuit IV can maintain the current drive of the electric motor M. On the other hand, the rotation speed of the electric motor increases, and as a result, the value of the right side increases, and eventually, when inequality 8 is not satisfied ((left side of inequality 8)<(right side of inequality 8)), driving of electric motor M , exceeds the maximum output voltage of the inverter circuit IV (maximum output voltage of the power supply Vdc). That is, the IV control signal of the PWM modulator PW and the output of the inverter circuit IV are in an overmodulation region where they do not match. Therefore, the actual rotation speed ω _m obtained by the rotation angle measurement unit VS and the rotation speed processing unit RSC is expressed by an equation ((left side of inequality 8)=( By substituting the right side of inequality 8)) and solving the above equation for the q-axis current i _q , the _{q -} axis current threshold i _qlim is required.

Similar to the smoothing unit 13a, the smoothing unit 13b smoothes each of the plurality of time-series voltage patterns generated by the voltage pattern generation unit 12 ( smoothing). That is, the smoothing unit 13b performs the smoothing process. Here, in the second embodiment, the smoothing section 13b generates the smoothed voltage pattern based on the determination result of the determination section 17. FIG. More specifically, when the determination result of the determining unit 17 indicates that the smoothed voltage pattern can be output by the inverter circuit (that is, when i _q ≤ i _qlim , in other words, when it is not in the overmodulation region), The smoothing unit 13b smoothes the voltage pattern according to Equation 1 (Ka>0) described above to obtain a smoothed voltage pattern. On the other hand, when the determination result of the determination unit 17 indicates that the smoothed voltage pattern cannot be output by the inverter circuit (i.e., when i _q > i _qlim , in other words, when it is in an overmodulation region), the smoothing unit 13b Let v _dqs (k)=v _dq (k). That is, in the overmodulation region, the smoothing function of the smoothing unit 13b based on the formula 1 is turned off, and the control method is switched to a method that does not use PWM. In other words, in Equation 1 above, Ka=0. This avoids a mismatch between the IV control signal of the PWM modulator PW and the output of the inverter circuit IV, so that the electric motor M can be driven more stably.

In this embodiment, the current measurement unit CS and the three-to-two phase conversion unit CV2 correspond to an example of a current acquisition unit that acquires the current flowing through the electric motor, and the rotation angle measurement unit VS and the rotation speed processing unit RSC , corresponds to an example of a rotation speed acquisition unit that acquires the rotation speed of the electric motor.

Next, the operation of this embodiment will be described. In the electric motor drive control system Sb of the second embodiment as described above, when the power is turned on, each necessary unit is initialized and started to operate. Then, for example, by executing a program, the CPU is functionally configured with a model prediction control section MCb, a two-to-three phase conversion section CV1, a three-to-two phase conversion section CV2, and a rotational speed processing section RSC. Control unit MCb is functionally configured with control unit 11 , voltage pattern generation unit 12 , smoothing unit 13 b , prediction unit 14 , voltage pattern selection unit 15 , PWM inverter control unit 16 and determination unit 17 .

Then, each of processing S11, processing S12b, processing S13, processing S14b, processing S15, processing S16, and processing S17 shown in FIG. is executed repeatedly. Processing S11, processing S13, processing S15, processing S16, and processing S17 in the second embodiment are the same as processing S11, processing S13, processing S15, processing S16, and processing S17 in the first embodiment, respectively. Description is omitted.

In the process S12b, similarly to the above-described process S12a, the three-to-two-phase converter CV2 converts the d-axis current i _d and the q-axis current i _q from the current values and rotation angle values of the phases acquired in the process S11 and outputs the obtained d-axis current i _d and q-axis current i _q to the model predictive control unit MCb, and the rotation speed processing unit RSC calculates , the rotational speed ω _m is obtained, and the obtained rotational speed ω _m is output to the model predictive control unit MCb. Further, in the second embodiment, the determination unit 17 further determines whether or not the smoothed voltage pattern can be output by the inverter circuit IV. More specifically, the determination unit 17 first substitutes the rotation speed ω _m obtained by the rotation speed processing unit RSC into the above equation in which the left side and the right side of the inequality 8 are equal, and the q-axis current i _q Find the q-axis current threshold i _qlim at the current rotational speed ω _m by solving for . Next, the determination unit 17 compares the q-axis current iq obtained by the three-to-two-phase conversion unit CV2 with the _q -axis current threshold _iqlim obtained above. As a result of this comparison, if the determined q-axis current i _q is equal to or less than the determined q-axis current threshold i _qlim , the determination unit 17 determines that output is possible (i _q ≤ i _qlim , non-overmodulation region). On the other hand, as a result of the comparison, if the determined q-axis current iq is not equal to or less than the determined _q -axis current threshold _iqlim , the determination unit 17 determines that the output is not possible ( _iq > _iqlim , overmodulation region). Then, the determination unit 17 notifies the smoothing unit 13b of this determination result.

In the processing S14b, similarly to the processing S14a, the smoothing unit 13b calculates the time-series voltage patterns for each of the plurality of time-series voltage patterns generated by the voltage pattern generation unit 12 in the processing S12, using Equation 1. It is smoothed as a time-series smoothed voltage pattern. Here, in the second embodiment, when the determination result of the determination unit 17 in the process S12b can be output (i _q ≤ i _qlim , non-overmodulation region), a preset predetermined Ka (Ka>0 ), and when the determination result of the determination unit 17 in the process S12b cannot be output (i _q >i _qlim , overmodulation region), Ka=0, and the smoothing unit 13b uses v _{Let dqs} (k)= _vdq (k).

In this way, the electric motor M is controlled and driven by the model predictive control so that the rotational speed ω _m ^* is the target value for the control purpose.

Simulations (numerical experiments) verified the effects of the motor drive control system Sb, the motor drive control device, and the motor drive control method implemented therein in this embodiment. FIG. 9 shows a simulation result of speed control in one embodiment. 9A, 9B and 9C show simulation results of speed control by the motor drive control system Sb in the second embodiment, FIG. 9A shows the rotation speed, FIG. 9B shows the _d -axis current id, FIG. 9C shows the q-axis current i _q . Each horizontal axis in FIGS. 9A to 9C is elapsed time, the vertical axis in FIG. 9A is rotational speed, the vertical axis in FIG. 9B is _d -axis current id, and the vertical axis in FIG. 9C is is the q-axis current i _q . Similar to the speed control simulation by the motor drive control system Sa in the first embodiment shown in FIG. 7, the control period of the model predictive control is 100 μsec and the carrier frequency is 10 kHz. In the linear region (i _q ≤ i _qlim , non-overmodulation region) where the smoothed voltage pattern can be output by the inverter circuit IV, the smoothness Ka is 0.9, and the overmodulation region (i _q > i _qlim ) has smoothness Ka=0. The simulation was performed by keeping the load torque constant, accelerating (increasing) the target speed, and varying the drive region across the boundary between the linear region and the overmodulation region. As can be seen from FIG. 9, since the voltage pattern is smoothed in the linear region, the current pulsation can be suppressed as in the first embodiment. Furthermore, in the overmodulation region where the speed is increased and the control using PWM becomes unstable, in the second embodiment, the voltage pattern is not smoothed from the linear region to the overmodulation region. , the speed control is stable.

As described above, the electric motor drive control system Sb, the electric motor drive control device, and the electric motor drive control method implemented therein in the second embodiment are the same as the electric motor drive control system Sa, the electric motor drive control device, and the same in the first embodiment. It has the same effect as the motor drive control method implemented in . The electric motor drive control system Sb, the electric motor drive control apparatus, and the electric motor drive control method implemented in the second embodiment are based on the judgment result of judging whether or not the inverter circuit IV can output the smoothed voltage pattern. Since the smoothed voltage pattern is generated by the motor M, the electric motor M can be stably driven.

The electric motor drive control system Sb, the electric motor drive control device, and the electric motor drive control method implemented therein in the second embodiment are based on the obtained current and rotational speed (driving state of the electric motor M), the previously obtained maximum voltage and Since it is determined whether or not the inverter circuit IV can output the smoothed voltage pattern based on the characteristic parameter, the determination can be performed in real time from the driving state of the electric motor M.

That is, when the model predictive control disclosed in Patent Document 1 and Patent Document 2 is used as a comparative example, when each effect in the first embodiment, the second embodiment, and the comparative example is qualitatively compared, Table 1 is as follows. Here, "⊚" indicates that the action and effect are favorable, "○" indicates that the action and effect are normal, and "X" indicates that the action and effect are unfavorable.

In the first and second embodiments described above, the motor drive control systems Sa and Sb, the motor drive control device, and the motor drive control method implemented therein may be configured so that the smoothness Ka can be adjusted. In such a case, for example, as indicated by dashed lines in FIGS. A digital low-pass filter unit (DLPF unit) 131 that smoothes a voltage pattern as a time-series smoothed voltage pattern, and a filter coefficient control unit 132 that controls the filter coefficient of the DLPF 131 so as to achieve a predetermined smoothness Ka. . The DLPF 131 and the filter coefficient control unit 132 as described above are functionally configured in the CPU, for example. The predetermined smoothness Ka is input from the outside by input means (not shown) connected to the MPC control unit MC, which can input numerical values such as a DIP switch, a rotary switch, and a keyboard, and is provided to the filter coefficient control unit 132. be done.

Through simulation (numerical experiments), in the first embodiment, effects of the motor drive control system Sa, the motor drive control device, and the motor drive control method implemented therein were verified for each smoothness. It should be noted that the second embodiment can also be simulated in the same manner.

FIG. 10 is a diagram showing speed control simulation results for different degrees of smoothness of speed deviation and current deviation in the output voltage range of the inverter circuit. 10A, 10B and 10C show the case where the smoothness Ka is 0.3, FIGS. 10D, 10E and 10F show the case where the smoothness Ka is 0.6, and FIG. 10H and FIG. 10I show the case where the smoothness Ka is 0.9. 10A, 10D and 10G show the rotation speed, each horizontal axis is elapsed time, and each vertical axis is rotation speed. 10B, 10E and 10H show the _d -axis current id, each horizontal axis of which is the elapsed time, and each of which the vertical axis is the _d -axis current id. Figures 10C, 10F and 10I show the _q -axis current iq, where each horizontal axis is the elapsed time and each vertical axis is the _q -axis current iq. In these smoothness-specific simulations, the control cycle of model predictive control is 100 μsec, and the carrier frequency is 10 kHz.

As can be seen from FIGS. 10 and 10C, FIGS. 10E and 10F, and FIGS. 10H and 10I, as the smoothness Ka is greatly adjusted, the current pulsations of the d-axis current i _d and the q-axis current i _q is reduced. Further, as can be seen from FIGS. 10A, 10D, and 10G, as the smoothness Ka is adjusted to a large value, the current ripple can be improved while ensuring the responsiveness. As a result of being able to improve the current ripple, the output torque ripple is also improved (reduced), and the speed ripple is also improved (reduced). By considering such a tendency, the smoothness Ka may be appropriately adjusted within a range allowed by the specifications of the motor drive control system S, for example, under 0≦Ka≦1. In FIGS. 10A, 10D and 10G, dashed lines indicate target values (reference values), and solid lines indicate measured values.

In addition, in the above-described first and second embodiments, the predetermined physical quantity related to the purpose of controlling the electric motor M was the rotation speed in order to control the speed. can be For example, for torque control, the predetermined physical quantity for the control purpose of the electric motor M may be the drive current. According to this, it is possible to provide the electric motor drive control systems Sa, Sb, the electric motor drive control apparatus, and the electric motor drive control method capable of torque control by drive current control.

In this case, in step S15, the prediction unit 14 obtains the d-axis current id by the above equation 2 using the smoothed _d -axis voltage _vds , and the above equation 3 using the smoothed q-axis voltage _vqs Obtain the q-axis current i _q by Therefore, in this case, Equations 4 and 5 are not used. Then, in step S16, the voltage pattern selection unit 15 selects the current predicted value [i _dq (k+1), i _dq (k+2)] are used, for example, in the evaluation formula g of the following equation 9 to quantitatively evaluate the time-series smoothed voltage patterns, and determine the plurality of time-series smoothed voltage patterns. From among them, the time-series smoothed voltage pattern corresponding to the current predicted value [i _dq (k+1), i _dq (k+2)] with the highest evaluation is selected. In the evaluation formula g of Formula 9, the smaller the evaluation value, the higher the evaluation.

Since the evaluation formula g of the above formula 9 is important for torque control, the current deviation of the q-axis current i _q is set as the first term. In order to prevent this, it is important to keep the _d -axis current id, which does not contribute to the generation of torque, at 0. Therefore, the current deviation of the _d -axis current id is defined as the second term, and these first and second terms It is constructed by linearly combining two terms with coefficients a and b. Therefore, the coefficients a and b are appropriately determined in advance according to the relative importance of the first term and the second term.

Although the present invention has been adequately and fully described above through embodiments with reference to the drawings in order to express the present invention, modifications and/or improvements to the above-described embodiments can easily be made by those skilled in the art. It should be recognized that it is possible. Therefore, to the extent that modifications or improvements made by those skilled in the art do not depart from the scope of the claims set forth in the claims, such modifications or improvements do not fall within the scope of the claims. is interpreted to be subsumed by

Sa, Sb Motor drive control system M Motor IV Inverter circuit PM PWM modulator MCa, MCb Model predictive control unit CS Current measurement unit VS Rotation angle measurement unit CV1 Two-phase three-phase conversion unit CV2 Three-phase two-phase conversion unit RSC Rotation speed processing Section 11 Control Section 12 Voltage Pattern Generation Sections 13a, 13b Smoothing Section 14 Prediction Section 15 Voltage Pattern Selection Section 16 PWM Inverter Control Section 17 Judgment Section 131 Digital Low Pass Filter Section (DLPF Section)
132 filter coefficient control unit

Claims (9)

A motor drive control device for controlling a motor driven by the output of an inverter circuit,
a voltage pattern generator that generates a plurality of different time-series voltage patterns that can be output by the inverter circuit;
a smoothing unit for smoothing each of the plurality of time-series voltage patterns generated by the voltage pattern generation unit as a time-series smoothed voltage pattern;
For each of the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit, a value of a predetermined physical quantity related to the purpose of controlling the electric motor when the time-series smoothed voltage pattern is input to the electric motor is a predicted value. a predictor that predicts as
A time-series smoothed voltage pattern corresponding to the highest evaluation prediction value among the prediction values of the electric motor predicted by the prediction unit, from among the plurality of time-series smoothed voltage patterns smoothed by the smoothing unit. a voltage pattern selection unit that selects a voltage pattern;
an inverter control unit that controls the inverter circuit based on the time-series smoothed voltage pattern selected by the voltage pattern selection unit;
Motor drive controller. further comprising a determination unit that determines whether the smoothed voltage pattern can be output by the inverter circuit,
The smoothing unit generates the smoothed voltage pattern based on the determination result of the determination unit.
The electric motor drive control device according to claim 1. The smoothing unit is
a digital low-pass filter unit for smoothing each of the plurality of time-series voltage patterns generated by the voltage pattern generation unit as a time-series smoothed voltage pattern;
A filter coefficient control unit that controls the filter coefficient of the digital low-pass filter unit so as to achieve a predetermined smoothness representing the degree of smoothing,
The electric motor drive control device according to claim 1 or 2. the predetermined physical quantity for the purpose of controlling the electric motor is the rotational speed;
The electric motor drive control device according to any one of claims 1 to 3. the predetermined physical quantity for the purpose of controlling the electric motor is a drive current;
The electric motor drive control device according to any one of claims 1 to 3. a current acquisition unit that acquires the current flowing to the electric motor;
A rotational speed acquisition unit that acquires the rotational speed of the electric motor,
The determination unit determines the smoothed voltage pattern based on the current acquired by the current acquisition unit, the rotation speed acquired by the rotation speed acquisition unit, the maximum voltage supplied to the inverter circuit, and the characteristic parameters of the electric motor. determine whether or not the circuit can output;
The electric motor drive control device according to any one of claims 1 to 5. A motor drive control method for controlling a motor driven by an output of an inverter circuit, comprising:
a voltage pattern generating step of generating a plurality of different time-series voltage patterns that can be output by the inverter circuit;
A smoothing step of smoothing each of the plurality of time-series voltage patterns generated in the voltage pattern generation step as a time-series smoothed voltage pattern;
For each of the plurality of time-series smoothed voltage patterns smoothed in the smoothing step, a value of a predetermined physical quantity related to the purpose of controlling the electric motor when the time-series smoothed voltage pattern is input to the electric motor is a predicted value. a prediction step of predicting as
A time-series smoothed voltage pattern corresponding to the highest evaluation predicted value among the predicted values of the electric motor predicted in the prediction step, from among the plurality of time-series smoothed voltage patterns smoothed in the smoothing step. a voltage pattern selection step of selecting a voltage pattern;
an inverter control step of controlling the inverter circuit based on the time-series smoothed voltage pattern selected in the voltage pattern selection step;
Electric motor drive control method. further comprising a determination step of determining whether the smoothed voltage pattern can be output by the inverter circuit;
The smoothing step generates the smoothed voltage pattern based on the determination result of the determining step.
The electric motor drive control method according to claim 7. an electric motor;
an inverter circuit that drives the electric motor;
an electric motor drive control unit that controls the electric motor by controlling the inverter circuit;
The electric motor drive control unit is the electric motor drive control device according to any one of claims 1 to 6,
Electric motor drive control system.

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