JP6119585B2 - Electric motor drive - Google Patents

Description

  The present invention relates to a motor drive device that drives an AC motor.

  2. Description of the Related Art Conventionally, there has been known an electric motor drive device that boosts DC power of a battery with a boost converter, converts it into AC power with an inverter, and outputs the AC power to an AC motor to drive the AC motor. In this electric motor drive device, the boost voltage input from the boost converter to the inverter has been controlled to be as constant as possible from the viewpoint of emphasizing control stability of the inverter.

  However, if the boosted voltage is constant when the operating region in the rotational speed-torque characteristic diagram of the motor output changes with time, the battery, boost converter, inverter, AC motor (these four parts are called "drive system components") ) May increase. Therefore, for example, the motor drive control system of Patent Document 1 determines the boost voltage of the boost converter based on the current rotational speed and torque command of the AC motor (MG) so that the total power loss of the entire system is minimized. doing.

JP 2007-325351 A

  In particular, an AC motor used as a power source in an electric vehicle such as a hybrid vehicle or an electric vehicle has a large change in an operation region depending on a driver's request, a road condition, and the like, and various change patterns. On the other hand, the upper limit of the variable range of the boosted voltage is determined by constants such as coils and capacitors constituting the circuit. Therefore, even if the optimum boosted voltage is determined from information on the current operation region, it is not always optimal in the future.

  The present invention has been created in view of the above points, and an object of the present invention is to provide a motor drive device that determines a boost voltage commanded to a boost converter so that current and future losses of the motor drive system are minimized. Is to provide.

  An electric motor drive device of the present invention includes a boost converter that boosts a power supply voltage (VL) of a DC power supply, an inverter that converts the boost voltage (VH) generated by the boost converter into AC power, and outputs the AC power, and rotation of the AC motor. The boost converter control unit that commands the boost voltage of the boost converter in a predetermined control cycle based on the number and the torque command, and controls the on / off of the switching element of the boost converter, and the inverter outputs desired AC power to the AC motor And an inverter control unit for controlling on / off of the switching element of the inverter.

The boost command generation means of the boost converter control unit includes a current loss estimation means, a future loss estimation means, and a boost command determination means.
The current loss estimation means estimates the power loss of any one or more of the current DC power supply, boost converter, inverter, and AC motor based on the current rotational speed and torque command of the AC motor. The future loss estimation means predicts the operating state of the AC motor at a predicted time point ahead of a predetermined period from the present time, and estimates one or more power losses of the DC power supply, the boost converter, the inverter, and the AC motor at the predicted time point To do.
The step-up command determination unit determines a step-up command (VH ^* ) to the step-up converter based on estimation results from the current loss estimation unit and the future loss estimation unit.
In the present invention, in addition to information on the current operating state of the AC motor, that is, the rotation speed and torque, the operating state at a predicted time point ahead of a predetermined period from the present is predicted, and the loss of the motor drive system is minimized in the present and the future. Thus, a boost command to the boost converter can be determined.

The “operating state of the AC motor at the time of prediction”, which is the basis for the future loss estimation means to estimate the power loss, is predicted as follows, for example. In one example, it is predicted from a change between a past value and a current value or a change between past values for at least one of the rotation speed or torque command of the AC motor acquired at each control cycle.
In another example, it is predicted by a signal from an external device that generates a predetermined “output request parameter” that changes an output request to the AC motor, or a control means of the external device.

In the case of an electric motor drive device that drives an AC motor that is a power source in a hybrid vehicle or an electric vehicle, the output request parameters include an accelerator pedal opening, a brake pedal opening, a clutch released or engaged state, or an output shaft of the AC motor. Load torque of the load directly connected to the. For example, when the accelerator pedal opening is increased, the output request for the AC motor is predicted to increase, and when the brake pedal opening is increased, the output request for the AC motor is predicted to decrease.
Further, in the case of an electric motor drive device that drives an AC motor in a hybrid vehicle including an engine and an AC motor as a power source, the output request parameter further includes an engine output torque. For example, when the engine output torque decreases and approaches EV running, the output demand for the AC motor is predicted to increase.

The step-up command determination means includes the total loss of the DC power supply, the boost converter, the inverter, the AC motor, or the loss of one or more specific components among them as “estimation results” from the current loss estimation means and the future loss estimation means. value is input Luke, or candidate value of boost command that is estimated based on the loss value are entered. If the loss value is entered, the boost command determining means selects a combination of a boost command (VH_rec1) and boost command future current loss of total loss or particular Component in current and future is minimized (VH_rec2), A boost command (VH ^* ) to the boost converter is determined based on the combination of the boost commands and the maximum boost voltage change amount (ΔVH).

The control block diagram corresponding to the electric current feedback control system of the electric motor drive device by embodiment of this invention. The control block diagram corresponding to the torque feedback control system of the electric motor drive device by embodiment of this invention. The control block diagram of the pressure | voltage rise command production | generation means of the electric motor drive device by 1st Embodiment of this invention. The control block diagram of the pressure | voltage rise command production | generation means of the electric motor drive device by 2nd Embodiment of this invention. The time chart which shows the effect of the pressure | voltage rise instruction | command process by embodiment of this invention. The main flowchart of the pressure | voltage rise instruction | command process (A) by embodiment of this invention. FIG. 7 is a sub-flowchart of one pattern of S07A in FIG. 6. FIG. 7 is a sub-flowchart of another pattern of S07A of FIG. The main flowchart of the pressure | voltage rise instruction | command process (B) by embodiment of this invention. 10 is a sub-flowchart of S07B of FIG. The control block diagram of the pressure | voltage rise command generation means of a prior art.

Embodiments of an electric motor drive device according to the present invention will be described below with reference to the drawings.
First, a configuration common to a plurality of embodiments will be described. The electric motor drive device 10 according to this embodiment is applied to a system that drives a motor generator (hereinafter referred to as “MG”) that is a power source of a hybrid vehicle or an electric vehicle.

[Overall configuration of electric motor drive device]
An overall configuration of an electric motor drive device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. 1 and 2 differ only in the configuration of the inverter control unit as will be described later.
As shown in FIG. 1 and FIG. 2, the electric motor drive device 10 boosts the DC power of the battery 2 as “DC power supply” by the boost converter 3 and converts it to three-phase AC power by the inverter 4. It is a device that outputs to MG6 as “AC motor”.

  In FIG. 1 and FIG. 2, the portion surrounded by the alternate long and short dash line is the range of the electric motor drive device 10. The main intention is that the range of the electric motor drive device 10 does not need to include the battery 2, the MG 6, and the rotation angle sensor 61. On the other hand, the entire illustrated range in which the battery 2 and the MG 6 are added to the electric motor driving device 10 is referred to as an “electric motor driving system”. In addition, the differentiator 62 and the current sensors 63 to 66 may or may not be included in the electric motor drive device 10.

First, the system configuration outside the range of the electric motor drive device 10 will be described.
The battery 2 is a chargeable / dischargeable power storage device such as a secondary battery such as nickel metal hydride or lithium ion or an electric double layer capacitor. The power supply voltage VL of the battery 2 is supplied to the boost converter 3. Further, the power supply current IL is detected by a current sensor 63 provided in the power supply path from the battery 2 to the boost converter 3.

The MG 6 of the present embodiment is, for example, a permanent magnet type synchronous three-phase AC motor. The MG6 is mounted on a hybrid vehicle or an electric vehicle, and functions as an electric motor that generates torque for driving the drive wheels via a transmission or the like by a power running operation, and a regenerative operation by torque transmitted from the engine or the drive wheels. It also has a function as a generator to generate electricity.
In the following description, it is assumed that the MG 6 performs a power running operation as “an electric motor that consumes electric power and generates torque”.

The rotation angle sensor 61 is a resolver, for example, and is provided in the vicinity of the rotor of the MG 6 to detect the electrical angle θ. The electrical angle θ detected by the rotation angle sensor 61 is input to the inverter control units 40 and 50, and used for calculations such as dq conversion. The electrical angle θ is converted into an electrical angular velocity ω by the differentiator 62 and input to the boost command generation means 32 of the boost converter control unit 30.
In addition to the resolver, a rotary encoder or the like may be used as the rotation angle sensor 61.
The electrical angular velocity ω [deg / s] is converted to a rotational speed N [rpm] by multiplying by a proportionality constant. In the following specification and drawings, “rotational speed converted from electrical angular velocity ω” is omitted, and the notation “rotational speed ω” is used as appropriate.

Next, the internal configuration of the electric motor drive device 10 will be described. The electric motor drive device 10 mainly includes a boost converter 3, an inverter 4, a boost converter control unit 30, and inverter control units 40 and 50.
The step-up converter 3 includes a coil, a capacitor, and two switching elements for step-up and step-down. Boost converter 3 boosts power supply voltage VL of battery 2 by, for example, two switching elements being alternately turned on / off by PWM control based on a boost duty. The boosted voltage VH is input to the inverter 4 as an inverter input voltage. Further, inverter input current IH is detected by current sensor 64 provided in the power supply path from boost converter 3 to inverter 4.

The inverter 4 is configured by six switching elements and the like that are bridge-connected. For example, an IGBT is used as the switching element. Alternatively, a MOS, a bipolar transistor or the like may be used. The inverter 4 converts the DC power into three-phase AC power by turning on / off each phase switching element by, for example, PWM control or phase control.
Since the configuration of boost converter 3 and inverter 4 itself is a well-known technique, detailed description thereof is omitted.

  Next, boost converter control unit 30 and inverter control units 40 and 50 will be described. These control units are configured by a microcomputer or the like, and are provided with a CPU, a ROM, an I / O (not shown), a bus line for connecting these configurations, and the like. Each control unit 30, 40, 50 executes control by software processing by executing a pre-stored program by the CPU or by hardware processing by a dedicated electronic circuit.

The boost converter control unit 30 includes a boost voltage range estimation unit 31 and a boost command generation means 32, and commands the boost voltage VH of the boost converter 3 at a predetermined control cycle.
The boost voltage range estimator 31 has a command value (step-up voltage VH that can be generated by the boost command generation means 32 based on the power supply voltage VL and power supply current IL, and the boost voltage (inverter input voltage) VH and inverter input current IH. Hereinafter, the range of VH ^{* (referred to} as “step-up command”) is estimated.

The boost command generation means 32 is a range of the boost voltage range VH_range estimated by the boost voltage range estimation unit 31 based on the torque command Trq ^* , the power supply voltage VL, and the power supply current IL acquired from the host vehicle control ECU (not shown). The voltage boost command VH ^* is generated within the output signal and is output to the PWM modulator 38. The present invention is characterized by the configuration and operation of the boost command generation means 32, and details thereof will be described later.

The PWM modulation unit 38 generates a PWM signal related to on / off switching of the step-up and step-down switching elements of the step-up converter 3. By controlling on / off of the step-up and step-down switching elements of the step-up converter 3 based on the PWM signal, a step-up voltage VH corresponding to the step-up command VH ^* is generated and input to the inverter 4.

The configuration of the inverter control unit is different between FIGS. 1 and 2. The inverter control unit 40 in FIG. 1 corresponds to the current feedback control type sine wave PWM control mode, and the inverter control unit 50 in FIG. 2 corresponds to the torque feedback control type rectangular wave control mode.
For example, as disclosed in Japanese Patent Application Laid-Open No. 2010-124544, etc., the electric motor driving device 10 is configured such that a sine wave PWM control mode, an overmodulation PWM control mode, and a rectangular shape according to the rotation speed and torque required for the output of the MG 6. Switch the wave control mode. The sine wave PWM control mode is used when output in a low rotation and low torque region is required, and the rectangular wave control mode is used when output in a high rotation and high torque region is required. In the middle region, the overmodulation PWM control mode is used. 1 and 2 show two control configurations in which one electric motor drive device 10 is changed as needed according to the required output of the MG 6.

(Current feedback control system)
As shown in FIG. 1, the inverter control unit 40 corresponding to the sine wave PWM control mode of the current feedback control system includes a current command generation unit 41, a current subtractor 42, a PI calculation unit 43, an inverse dq conversion unit 44, and a dq conversion. Part 45.
Based on the torque command Trq ^* , the current command generation unit 41 generates a d-axis current command Id ^* and a q-axis current command Iq ^* using a map or a mathematical expression. Hereinafter, “d-axis current and q-axis current” are appropriately expressed as “dq-axis current”.

The current subtractor 42 calculates dq-axis current deviations ΔId and ΔIq, which are the differences between the dq-axis currents Id and Iq fed back from the dq converter 45 and the dq-axis current command values Id ^* and Iq ^* .
The PI calculation unit 43 calculates the dq axis voltage commands Vd ^* and Vq ^* by the PI calculation so that the dq axis current deviations ΔId and ΔIq converge to 0, respectively.
The inverse dq conversion unit 44 converts the dq axis voltage commands Vd ^* and Vq ^* into three-phase voltage commands Vu ^* , Vv ^* , and Vw ^* based on the boost voltage VH and the electrical angle θ acquired from the rotation angle sensor 61. And output to the PWM modulator 48.

The PWM modulation unit 48 provided in the drive circuit of the inverter 4 generates PWM signals UU, UL, VU, VL, WU, and WL related to on / off switching of the switching element of the inverter 4. A desired three-phase AC voltage is generated by controlling on / off of the switching element of the inverter 4 based on the PWM signals UU, UL, VU, VL, WU, WL. By applying this three-phase AC voltage to MG6, the drive of MG6 is controlled so that torque according to torque command Trq ^* is output.

The dq conversion unit 45 receives phase current detection values from current sensors 65 and 66 provided on the power line connected from the inverter 4 to the MG 6. In this embodiment, detected values of the U-phase current Iu and the W-phase current Iw are input from the current sensors 65 and 66 provided in the U-phase and the W-phase, and the remaining V-phase current Iv is estimated based on Kirchhoff's law. doing. In other embodiments, any two-phase current may be detected, and a three-phase current may be detected. Or you may employ | adopt the technique (Unexamined-Japanese-Patent No. 2013-172591 etc.) which estimates another two-phase electric current based on the detected current value of one phase.
The dq converter 45 converts the three-phase currents Iu, Iv, and Iw into dq currents Id and Iq based on the electrical angle θ acquired from the rotation angle sensor 61 and feeds it back to the current subtractor 42.

When applying the over-modulation PWM control mode of the current feedback control method, a voltage amplitude correction unit is provided between the PI calculation unit 43 and the inverse dq conversion unit 44, and the amplitude of the voltage commands Vu ^* , Vv ^* , Vw ^* . Is corrected so as to be distorted from the sine wave waveform, thereby increasing the voltage utilization rate of the fundamental wave component.

(Torque feedback control system)
As shown in FIG. 2, the inverter control unit 50 corresponding to the torque feedback control type rectangular wave control mode includes a torque subtractor 52, a PI calculation unit 53, a rectangular wave generator 54, a dq conversion unit 55, and a torque calculation unit 56. Have

The torque subtractor 52 calculates a torque deviation Δtrq that is a difference between the torque calculation value Trq fed back from the torque calculation unit 56 and the torque command Trq ^* .
PI calculation unit 53 calculates voltage phase command VΨ by PI calculation so that torque deviation Δtrq converges to 0 so that torque calculation value Trq follows torque command Trq ^* .
The rectangular wave generator 54 generates a rectangular wave based on the voltage phase command VΨ, the boosted voltage VH, and the electrical angle θ, and outputs the three-phase voltage commands Vu ^* , Vv ^* , Vw ^* to the signal generator 58.

The signal generator 58 generates voltage command signals UU, UL, VU, VL, WU, WL for switching on / off of the switching elements of the inverter 4 based on the three-phase voltage commands Vu ^* , Vv ^* , Vw ^*. To do. The operation of the inverter 4 is the same as that of the current feedback control method.
The dq converter 55 dq-converts the three-phase currents Iu, Iv, and Iw into dq currents Id and Iq, and outputs the dq current to the torque calculator 56 as in the current feedback control type dq converter 45.

The torque calculation unit 56 calculates a torque calculation value Trq based on the dq-axis currents Id and Iq using a map or equation (1) and feeds it back to the torque subtractor 52.
Trq = p × {ψ × Iq + (Ld−Lq) × Id × Iq} (1)
The symbols are as follows.
p: number of pole pairs of AC motor Ld, Lq: d-axis self-inductance, q-axis self-inductance ψ: armature linkage magnetic flux of permanent magnet

[Configuration of boost command generation means]
Next, two embodiments of the detailed configuration of the boost command generation means 32 that is a feature of the present invention will be described with reference to FIGS. The step-up command generation means of the first embodiment shown in FIG. 3 is denoted by “321”, and the step-up command generation means of the second embodiment shown in FIG. 4 is denoted by “322”. In the two embodiments, substantially the same components are denoted by the same reference numerals and description thereof is omitted.

Prior to the description of the embodiment of the present invention, FIG. 11 shows a configuration of a boost command generation means in Patent Document 1 as a prior art. In addition, the four functional components of the battery 2, the boost converter 3, the inverter 4, and the MG 6 in the motor drive system are hereinafter referred to as “drive system components”. In addition, simply “loss” means “power loss”.
The boost command generation means 329 determines the current loss estimation means 33 to estimate each loss of the drive system components based on the current rotational speed ω of the MG 6 and the torque command Trq ^* , and boost the voltage so that the sum of the losses is minimized. A boost command VH ^* to the converter 3 is generated.

According to the prior art, the system loss can be reduced according to the change in the operation region required for the MG 6 as compared with the case where the boost voltage VH of the boost converter 3 is constant.
However, the MG 6 used as a power source in an electric vehicle such as a hybrid vehicle or an electric vehicle has a large change in the operation region depending on a driver's request, a road condition, and the like, and various change patterns. On the other hand, the upper limit of the variable range of the boost voltage VH is determined by constants such as the inductance of the coil and the capacitance of the capacitor constituting the circuit of the boost converter 3. Therefore, even if the optimum boosted voltage VH is determined from information on the current operation region, it is not always optimal in the future.

Therefore, in the present invention, in addition to information on the current operating state of the MG 6, a future operating state of the MG 6 at a prediction time point ahead of the current period is predicted, and the loss of the motor drive system is minimized at the present time and in the future. The purpose is that.
The following two embodiments have different configurations for predicting future operation states.

(First embodiment)
As shown in FIG. 3, the boost command generation means 321 includes a current loss estimation means 33, a future rotation speed prediction means 34, a future torque prediction means 35, a future loss estimation means 36, and a boost command determination means 37.

The current loss estimation means 33 estimates each loss of the drive system component based on the current rotational speed ω6 of the MG 6 and the torque command Trq ^* , as in the above-described conventional technology. Here, the loss of any one or more of at least four components may be estimated. “Current rotation speed ω and torque command Trq ^* ” means “a value acquired at the current control timing” among values acquired at a predetermined control cycle. This control cycle may be set as appropriate.

The future rotational speed predicting means 34 and the future torque predicting means 35 predict the estimated rotational speed value ω_est and the estimated torque value Trq_est of the MG 6 at the time of prediction. In the first embodiment, the previous value of the rotational speed ω and the torque command Trq ^* , that is, the “value acquired at the previous control timing” is stored and acquired. Then, based on the change between the previous value and the current value of the rotational speed ω and the torque command Trq ^* , the rotational speed estimated value ω_est and the torque estimated value Trq_est of the MG 6 at the prediction time are predicted.
The future loss estimation means 36 estimates each loss of the drive system component, or any one or more losses based on at least one of the estimated rotational speed value ω_est and the estimated torque value Trq_est of the MG 6 at the time of prediction.

  Here, the prediction based on the change between the previous value and the current value is performed by extrapolating the value with respect to the time axis, for example. In addition, “Previous value and current value”, “Previous value and current value”, “Previous value and previous value”, etc. It may be predicted based on the change in

The current loss estimation unit 33 and the future loss estimation unit 36 output the loss of each component or the current boost command (recommended value) VH_rec1 and the future boost command (recommended value) VH_rec2 to the boost command determination unit 37 as estimation results. . Boost command determining means 37 generates boost command VH ^* to boost converter 3 based on the estimation results obtained from current loss estimating means 33 and future loss estimating means 36. Details of the process of generating the boost command VH ^* will be described later with reference to a flowchart.

(Second Embodiment)
As shown in FIG. 4, in the second embodiment, the current loss estimation means 33 and the future rotation speed prediction means 34 are based on the signal from the external device 7 or the control means of the external device, and the MG 6 at the prediction time point. The estimated rotational speed value ω_est and the estimated torque value Trq_est are predicted.

The external device 7 is a generic term for a device that generates a predetermined “output request parameter” for changing an output request to the MG 6. Specific examples of the output request parameter include an accelerator pedal opening degree, a brake pedal opening degree, a clutch released or engaged state, or a load torque of a load (such as a hydraulic pump) directly connected to the output shaft of the MG 6. For example, when the accelerator pedal opening is increased, the output request for MG6 is predicted to increase, and when the brake pedal opening is increased, the output request for MG6 is predicted to decrease.
In the case of a hybrid vehicle, the output request parameter further includes an engine output torque. For example, when the engine output torque decreases and approaches EV running, the output request for MG 6 is predicted to increase.

When a signal related to such an output request parameter is input from each external device or the control ECU, the current loss estimation unit 33 and the future rotation number prediction unit 34 allow the MG 6 rotation number estimated value ω_est and torque estimation at the time of prediction. Predict the value Trq_est. Hereinafter, the future loss estimation means 36 and the boost command determination means 37 are the same as those in the first embodiment.
Moreover, you may combine the prediction method of 1st Embodiment and 2nd Embodiment.

[Operational effects of boost command processing]
The effects of the boost command processing by the electric motor drive device 10 having the above configuration will be described with reference to the time chart of FIG. This comparative example corresponds to the prior art disclosed in Patent Document 1.
5A to 5D, the horizontal axis is a common time axis, and the vertical axis is (a) voltage, (b) rotation speed, (c) torque command, and (d) loss. “T” on the horizontal axis of (a) indicates a control cycle, and times t10, t20, and t30 indicate control timings at which a new boost command VH ^* is commanded.

In (a), the solid line and the alternate long and short dash line indicate the boost voltage VHp and the boost command VH ^* p of the present embodiment, and the long broken line and the short dashed line indicate the boost voltage VHc and the boost command VH ^* c of the comparative example. In (d), a solid line shows the loss PLp of this embodiment, and a long broken line shows the loss PLc of a comparative example. The maximum rate (slope) r _{VH of the} boost voltage VH and the maximum change amount ΔVH from the present to the next control timing are determined by the circuit characteristics of the boost converter 3.

Here, as shown in (b) and (c), the boost command VH ^* generated when the rotational speed ω gradually increases and the torque command Trq ^* is constant from time t10 to time t30 will be compared.
The boosted voltage at time t10 is VH1 in both the present embodiment and the comparative example. In the drawing, the lines are slightly shifted in order to prevent the lines from overlapping and difficult to see.

In the comparative example, at time t10, the boost command VH ^* c1 is commanded so that the total system loss is minimized based on the current operating state of the MG 6 (at time t10). Boosted voltage VHc rises at maximum rate r _VH and maintains a constant value when it reaches boosted command VH ^* c1 at time t12.
At time t20, which is the next control timing, a boost command VH ^* c2 greater than boost command VH ^* c1 is commanded again based on the operating state of MG 6 at time t20. Boosted voltage VHc rises again from time t20. However, since the maximum rate r _VH that can be increased is regulated, the boost command VH ^* c2 cannot be reached by time t30.

On the other hand, in the present embodiment, at time t10, in addition to the current operating state of MG6 (at time t10), the operating state of MG6 at time t20 in the future is predicted, and the current and future system loss voltage is minimized. The boost command VH ^* p1 is commanded so that This boost command VH ^* p1 is larger than VH ^* c1 of the comparative example, and is considered to be excessive at time t10. As a result, the boost voltage VHp rises at the maximum rate r _VH from time t10 to time t20, and reaches the boost command VH ^* p1 at time t20.
At time t20, the boost command VH ^* p2 is commanded again. The boost voltage VHp continues to rise at the maximum rate r _VH after time t20, and reaches the boost command VH ^* p2 at time t30.

In FIG. 5A, in the comparative example in which the boost command VH ^* c2 and VH ^* p2 at the time t20 in the comparative example and the present embodiment are equal but the future is not anticipated at the time t10, the time t30 However, in the present embodiment in which the boost command VH ^* p1 is commanded in anticipation of the future at time t10, the boost voltage VHp does not reach the boost command VH ^* c2 at time t10. VH ^* p2 can be reached.

Further, as shown in FIG. 5D, the loss PLc1 of the comparative example at time t10 and the loss PLp1 of the present embodiment are equivalent.
In the comparative example in which the boost command VH ^* c1 at time t10 is set low, loss PLc1 is constant at a relatively low value from time t10 to time t13. However, at time t13, the margin of the boosted voltage VHc with respect to the operation of MG6 disappears, the loss PLc increases rapidly, and increases to PLc2 at time t20. When a new boost command VH ^* c2 is commanded at time t20, loss PLc begins to decrease and decreases to PLc3 at time t30.

On the other hand, in the present embodiment in which the boost command VH ^* p1 at time t10 is set high, the boost voltage VHp tends to be excessive immediately after time t10, and the loss PLp starts to increase gradually from time t11, and PLp2 at time t20. Increase to. This PLp2 is smaller than the PLc2 of the comparative example. When a new boost command VH ^* p2 is commanded at time t20, loss PLp starts to decrease and decreases to PLp3 at time t30.

Thus, the loss PLp of the present embodiment is larger from time t11 to time t14, and the loss PLc of the comparative example is larger after time t14. When this is compared with the cumulative loss, the region A (c) where the loss PLc of the comparative example exceeds the loss PLp of the present embodiment than the region A (p> c) where the loss PLp of the present embodiment exceeds the loss PLc of the comparative example. > P) has a larger area. That is, the cumulative loss is larger in the comparative example. Therefore, in the present embodiment, the cumulative loss of the system can be reduced by determining the boost command VH ^{* in} anticipation of the future.

[Step-up command processing routine]
Next, a plurality of patterns of boost command processing routines by the boost command generating means 32 will be described with reference to the flowcharts of FIGS. 6 to FIG. 10 show the main flow. 7 and 8 show a subflow of “S07A” in FIG. 6, and FIG. 10 shows a subflow of “S07B” in FIG. Here, the patterns are divided by paying particular attention to how the boost command determining means 37 determines the boost command VH ^* .
In the description of the flowchart below, the symbol “S” means a step. In addition, steps that are substantially the same in a plurality of patterns are denoted by the same step numbers and description thereof is omitted.

  Further, in S04 and S05 of the main flow, the boost command generation unit 32 predicts the future rotation speed estimated value ω_est and torque estimated value Trq_est based on the change between the previous value and the current value. A description will be given collectively assuming that both the boost command generation means 321 and the boost command generation means 322 of the second embodiment predicted based on a signal from the external device 7 are included. When applied to an embodiment in which prediction is performed by either one of the methods, an extra step may be omitted as appropriate.

First, the A pattern of the main flow of the boost command process will be described with reference to FIG.
The boost command generation means 32 acquires the torque command Trq ^* from the host vehicle control CPU to the MG 6 in S01, and acquires the rotation speed ω of the MG 6 from the rotation angle sensor 61 in S02. As shown in FIGS. 3 and 4, the rotational speed ω and the torque command Trq ^* are input to both the current loss estimation unit 33 and the future loss estimation unit 36.

In another embodiment, torque command Trq ^** processed by step-up converter control unit 30 or inverter control units 40, 50 is used in place of torque command Trq ^* acquired from the host vehicle control ECU in S01. May be. Examples of processing include torque command limitation according to the operating state of MG6, correction of a command from the host ECU for the purpose of suppressing a sudden change in torque command by a filter, or based on a rotational speed command value commanded from the host ECU. The torque command Trq ^** may be generated inside the boost converter control unit 30 or the inverter control units 40 and 50.
Further, instead of the rotational speed ω detected by the rotational speed sensor 61 in S02, an estimated rotational speed estimated inside the boost converter control unit 30 or the inverter control units 40 and 50 may be used.

The next S03A and S04 to S06A are executed in parallel.
In S03A, the current loss estimation means 33 calculates each current loss of the drive system components (battery 2, boost converter 3, inverter 4, MG6 ⁾ based on the acquired rotational speed ω and torque command Trq ^* .

As described above, S04 and S05 are steps assuming the boost command generation means 32 including both configurations of the first and second embodiments. In step S04, the future rotation speed prediction unit 34 and the future torque prediction unit 35 of the boost command generation unit 32 acquire a signal from the external device 7 that generates the output request parameter. In the subsequent S05, the operation state of the MG 6 in the future (predicted time) is predicted based on the signal from the external device 7, or the change between the previous value and the current value of the rotational speed ω and the torque command Trq ^* . The “previous value and current value” may be a past value and a current value, or a past value, as described in the configuration explanation.

  The future loss estimation means 36 is a drive system component (battery 2, boost converter 3, inverter) based on the “operating state of MG6 at the predicted time” predicted by the future rotation speed prediction means 34 and the future torque prediction means 35 in S06A. 4, each loss at the prediction time of MG6) is calculated.

The step-up command determination unit 37 acquires the current loss calculated by the current loss estimation unit 33 in S03A and the future loss calculated by the future loss estimation unit 36 in S06A. In S07A, the boost command determination means 37 selects the current boost command VH_rec1 based on the current loss and the future boost command VH_rec2 based on the future loss, and the current and future total loss or the loss of the specific component. The boost command VH ^* that minimizes is determined.

Here, the “current and future losses” do not necessarily evaluate the current and future losses equally, but may be weighted so that, for example, the current losses are emphasized. Further, the loss of the four drive system components may be weighted to the loss of the specific component when it is desired to suppress the heat generation of the specific component, instead of evaluating the total loss of the four drive system components equally.
In the last step S08, the boost converter control unit 30 controls the boost converter 3 based on the calculated boost converter output voltage.

For the above S07A, the subflows of two patterns will be described in more detail.
In the sub-flow of S07A shown in FIG. 7, the boost command determination means 37 selects a combination of the current boost command VH_rec1 and the future boost command VH_rec2 that minimizes the current and future total loss or the loss of the specific component in S071. .

In S072, the change from the current boost voltage VH is maximized based on the “boost converter parameters” such as the inductance of the coil and the capacitance of the capacitor, the operating state of the MG 6 and the SOC (charge amount) of the battery 2, etc. An allowable “maximum boost voltage change amount ΔVH” is obtained. ΔVH is a positive value when the operation of MG6 is a power running operation, and is a negative value when the operation is regenerative.
In S073, when MG6 performs a power running operation | movement, the success or failure of Formula (2) is determined.
ΔVH ≧ (VH_rec1−VH_rec2) (2)
In addition, when MG6 performs regenerative operation | movement, the direction of the inequality sign of Formula (2) becomes reverse.

When YES in S073, the current boost command VH_rec1 is set as the boost command VH ^* to the boost converter 3 in S074. That is, when the difference between the current boost command VH_rec1 and the future boost command VH_rec2 is small, it is determined that the current boost command VH_rec1 may be adopted.

  On the other hand, when NO in S073, in S075, the combination of the current boost command VH_rec1 ′ and the future boost command VH_rec2 ′ that minimizes the current and future total loss or the loss of the specific component is next to the current combination. Select and return to before S072. The steps of S075 and S072 are repeated until YES is determined in S073. Thus, in the pattern shown in FIG. 7, a combination of boost commands that minimizes the loss is searched for among the combinations that satisfy Expression (2).

The S07A subflow shown in FIG. 8 differs from the pattern shown in FIG. 7 in that S071 to S074 are the same. When NO in S073, S076 is executed instead of S075 in FIG. In S076, the “boost voltage current value VH + ΔVH” is set as the boost command VH ^* to the boost converter 3. That is, the maximum change amount allowed for the current value is changed. In this pattern, a loop calculation for searching for a combination of boost commands satisfying Expression (2) can be avoided with respect to the pattern of FIG. 7, and the calculation load can be reduced.
The current boost command VH ^* may be adopted instead of the boost voltage current value VH, and “current boost command VH ^* + ΔVH” may be used as the boost command VH ^* to the boost converter 3.

Next, the B pattern of the main flow of the boost command process will be described with reference to FIG. The main flow of the B pattern shown in FIG. 9 is different in that S03B, S06B, and S07B are executed instead of S03A, S06A, and S07A of the A pattern shown in FIG.
That is, the A pattern and the B pattern have different forms of “estimation results” output from the current loss estimation means 33 and the future loss estimation means 36 to the boost command determination means 37 in the block diagrams of FIGS. A mode in which the current loss estimation unit 33 and the future loss estimation unit 36 output “each loss” corresponds to the A pattern, and a mode in which the current loss estimation unit 33 and the future loss estimation unit 36 output “VH_rec1, VH_rec2”, respectively. Corresponds to the B pattern.

In S03B, the current loss estimation means 33 calculates the current loss of each drive system component, and further selects the current boost command (recommended value) VH_rec1 that minimizes the current total loss or the loss of the specific component.
In S06B, the future loss estimation means 36 calculates each loss of the drive system component at the predicted time, and further selects a future boost command (recommended value) VH_rec2 that minimizes the total loss or the specific component loss at the predicted time. .

The step-up command determination unit 37 that has acquired the current step-up command VH_rec1 and the future step-up command (recommended value) VH_rec2 from the current loss estimation unit 33 and the future loss estimation unit 36, in S07B, present and future total loss or loss of a specific component. The boost command VH ^* that minimizes is determined.

The subflow of S07B shown in FIG. 10 does not have S071 with respect to the subflow of the A pattern shown in FIG. 8, and the steps after S072 are the same. In S076, as in the above description, “current boost command VH ^* + ΔVH” may be used as the boost command VH ^* to boost converter 3, instead of “boost voltage current value VH + ΔVH”.

(Other embodiments)
The electric motor drive device 10 of the above embodiment is applied as a device for driving the MG 6 that is a power source of a hybrid vehicle or an electric vehicle. The hybrid vehicle and the electric vehicle include a fuel cell vehicle using a fuel cell as a power source for charging a DC power source.
Further, the output request parameter for changing the output request to the MG 6 is not limited to those exemplified in the above description, and may include any parameter assumed from the same viewpoint.

Furthermore, the motor driving device of the present invention is not limited to driving an AC motor as a power source of a vehicle, and in an AC motor for auxiliary equipment of a vehicle or an AC motor used for other than a vehicle, the operating state changes particularly. It can be effectively applied to large ones.
As mentioned above, this invention is not limited to the said embodiment at all, In the range which does not deviate from the meaning of invention, it can implement with a various form.

10: Electric motor drive device,
2 ... Battery (DC power supply),
3 ... Boost converter, 30 ... Boost converter controller,
32 (321, 322) ... boost command generation means,
33 ... Current loss estimation means, 36 ... Future loss estimation means,
37 ... Boost command determining means,
4 ... inverter, 40, 50 ... inverter control unit,
6: Motor generator, MG (AC motor).

Claims (5)

A boost converter (3) for boosting the power supply voltage (VL) of the DC power supply (2);
An inverter (4) for converting a boosted voltage (VH) by the boost converter into AC power and outputting the AC power to the AC motor (6);
A boost converter control section (30) for commanding a boost voltage of the boost converter at a predetermined control cycle based on a rotational speed and a torque command of the AC motor, and controlling on / off of a switching element of the boost converter;
An inverter control unit (40, 50) for controlling on / off of a switching element of the inverter so that the inverter outputs desired AC power to the AC motor;
With
The boost command generation means (32) of the boost converter control unit includes:
Current loss estimating means (33) for estimating a power loss of any one or more of the DC power supply, the boost converter, the inverter and the AC motor based on the current rotational speed and torque command of the AC motor; ,
Predicts the operating state of the AC motor at a predicted time point ahead of a predetermined period from the present time, and estimates one or more power losses of the DC power source, the boost converter, the inverter, and the AC motor at the predicted time point Future loss estimation means (36) for
A boost command determining means (37) for determining a boost command (VH ^* ) to the boost converter based on estimation results by the current loss estimating means and the future loss estimating means;
I have a,
The boost command determination means includes a current boost command based on a loss estimated by the current loss estimation means and a future boost command based on a loss estimated by the future loss estimation means. Selecting a combination of the current boost command (VH_rec1) and the future boost command (VH_rec2) that minimizes power loss of any one or more of the boost converter, the inverter, and the AC motor; And a step-up command to the step-up converter based on a maximum amount of change in step-up voltage (ΔVH ).   The future loss estimation means at the prediction time point predicted from a change between a past value and a current value or a change between past values for at least one of the rotation speed or torque command of the AC motor acquired at each control cycle. The electric motor drive device according to claim 1, wherein power loss is estimated based on an operating state of the AC electric motor.   The future loss estimating means generates the predetermined output request parameter for changing the output request for the AC motor, or the AC at the prediction time point predicted by a signal from the control means of the external apparatus. The electric motor drive device according to claim 1, wherein the electric power loss is estimated based on an operating state of the electric motor. An electric motor drive device for driving the AC electric motor as a power source in a hybrid vehicle or an electric vehicle,
The output request parameter is at least one of an accelerator pedal opening, a brake pedal opening, a clutch released or engaged state, or a load torque of a load directly connected to the output shaft of the AC motor. The electric motor drive device according to claim 3. A motor drive device for driving the AC motor in a hybrid vehicle including an engine and the AC motor as a power source,
The electric motor drive device according to claim 4, wherein the output request parameter further includes an engine output torque.

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