Patent Application
20250192713
The present invention relates to a configuration of a motor control device that controls driving of a motor and a control method thereof, and more particularly to a technique that is effective when applied to an in-vehicle motor in which a load changes according to a surrounding environment and a vehicle state.
An in-vehicle motor mounted on a hybrid electric vehicle (HEV) or an electric vehicle (EV) is required to have performance with low loss and high efficiency. In addition, one of important values provided is quietness, which is not found in the engine vehicle, and there is also a strong demand for low noise vibration (NV). In recent years, the spread of HEV and EV has rapidly progressed, and the demand for low loss and low NV has further increased with the improvement of driving quality and the introduction of automatic driving.
An in-vehicle motor is generally driven and controlled by pulse width modulation (PWM) control. However, since loss and NV in the PWM control are in a certain trade-off relationship, control for switching a pulse pattern according to a threshold designed in advance is performed.
As a background art of the present technical field, for example, there is a technique such as PTL 1. PTL 1 discloses “an electric motor control device including a control device 60 including a carrier frequency control unit 77 that can weight according to surrounding environment of a vehicle, a use state (for example, a traveling state), or the like”. (paragraphs and of PTL 1)
PTL 1: JP 2018-99003 A
However, since the load of an in-vehicle motor mounted on an automobile constantly changes according to the surrounding environment and the vehicle state during traveling, there is a possibility that it is not possible to select an appropriate PWM that achieves both low loss and low NV in a scene where a plurality of surrounding environments and a plurality of vehicle states overlap.
In PTL 1 described above, the weighting of low loss and low NV is determined in specific surrounding environment and vehicle state such as nighttime or a case where the outside temperature is high and the traveling state of the vehicle is low speed, and there is a possibility that appropriate PWM cannot be selected in a scene in which a plurality of these conditions overlap. In addition, when a carrier frequency is changed, in a case where a frequency variation is large, there is a possibility that the auditory perception of the driver deteriorates.
In this regard, an object of the present invention is to provide a motor control device and a motor control method capable of appropriately achieving both low loss and low NV in a scene where a plurality of surrounding environments and a plurality of vehicle states overlap.
In order to solve the above problems, the present invention is a motor control device which is connected to an AC motor and PWM-controls a power converter that performs power conversion from DC power to AC power. The motor control device includes: a plurality of PWM pulse patterns; a pulse pattern determination unit that sets a pulse pattern for performing the PWM control; an evaluation unit that determines a priority of a total loss of the AC motor and the power converter and vibration noise of the AC motor; and a loss/NV calculation unit that calculates a value of the total loss and a value of the vibration noise in torque and rotation speed for each pulse pattern. The evaluation unit determines the priority on the basis of a parameter regarding at least one of a surrounding environment, mode designation by intention of a driver, a remaining battery amount, a driving operation point, and a vehicle state, and the pulse pattern determination unit sets the pulse pattern by using the priority determined by the evaluation unit, the value of the total loss, and the vibration noise.
In addition, the present invention is a motor control method for PWM-controlling an AC motor. The motor control method includes: (a) a step of determining a priority of a total loss of the AC motor and a power converter that drives the AC motor, and vibration noise of the AC motor; (b) a step of determining the priority on the basis of a parameter regarding at least one of a surrounding environment, mode designation by intention of a driver, a remaining battery amount, a driving operation point, and a vehicle state; and (c) a step of setting a pulse pattern by using the priority determined in the step (b), a value of the total loss, and the vibration noise.
According to the present invention, it is possible to achieve a motor control device and a motor control method capable of appropriately achieving both low loss and low NV in a scene where a plurality of surrounding environments and a plurality of vehicle states overlap.
Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.
Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that in the drawings, the same components are denoted by the same reference numerals, and the detailed description of overlapping components is omitted.
A motor drive system according to a first embodiment of the present invention will be described with reference to
As illustrated in
The inverter 3 includes a DC/AC conversion circuit 31, a gate drive circuit 32, and a capacitor 33 which is a smoothing capacitor.
The permanent magnet synchronous motor 2 is a three-phase AC motor having three coils Lu, Lv, and Lw.
The rotational position detector 4 outputs, to the motor control device 1, a rotational position 0 of the permanent magnet synchronous motor 2 detected by the rotational position sensor 8.
The motor control device 1 generates a pulse width modulation (PWM) pulse signal on the basis of an input torque command T*, the three-phase current values Iu, Iv, and Iw detected by the current detection unit 7, and the rotational position θ of the permanent magnet synchronous motor 2 input from the rotational position detector 4, and outputs the PWM pulse signal to the gate drive circuit 32 of the inverter 3.
The DC/AC conversion circuit 31 is configured by connecting three arms in parallel, each arm having two switching elements connected in series, converts DC power output from the high-voltage battery 5 into three-phase AC power, and outputs the three-phase AC power to the permanent magnet synchronous motor 2. The three-phase current values Iu, Iv, and Iw flow from the DC/AC conversion circuit 31 to the permanent magnet synchronous motor 2.
The gate drive circuit 32 controls ON/OFF of the gates of a total of six switching elements of the DC/AC conversion circuit 31 on the basis of the PWM pulse signal generated by the motor control device 1.
The configuration of the motor control device 1 will be described with reference to
As illustrated in
The current command generation unit 11 generates current commands Id* and Iq* on the basis of a power supply voltage Hvdc output from the high-voltage battery 5, the torque command T*, and an angular velocity ωr output from the speed calculation unit 12, and outputs the current commands Id* and Iq* to the current control unit 15.
The speed calculation unit 12 outputs the angular velocity ωr on the basis of the rotational position θ of the permanent magnet synchronous motor 2.
The three-phase/dq current conversion unit 13 converts the three-phase current values Iu, Iv, and Iw detected by the current detection unit 7 into a d-axis current Id and a q-axis current Iq, and outputs the d-axis current Id and the q-axis current Iq to the current control unit 15.
The pulse pattern determination unit 14 determines a pulse pattern for PWM control on the basis of the power supply voltage Hvdc, the torque command T*, the angular velocity ωr, and the respective input signals of Mode, inverter/motor temperatures Tempinv,mot, and Drv set, and outputs the pulse pattern to the carrier wave frequency adjustment unit 17 and the zero-phase addition unit 18.
A Mod mode signal is input from the pulse pattern determination unit 14 to the zero-phase addition unit 18, and the respective signals of Flagsynasyn, Nc, and fcasyn are input from the pulse pattern determination unit 14 to the carrier wave frequency adjustment unit 17.
The current control unit 15 outputs dq-axis voltage commands Vd* and Vq* to the dq/three-phase voltage conversion unit 16 and the carrier wave frequency adjustment unit 17 on the basis of the current commands Id* and Iq*, and the d-axis current Id and the q-axis current Iq.
The dq/three-phase voltage conversion unit 16 outputs three-phase voltage commands Vu*, Vv*, and Vw* to the zero-phase addition unit 18 on the basis of the voltage commands Vd* and Vq* and the rotational position 0 of the permanent magnet synchronous motor 2.
The carrier wave frequency adjustment unit 17 adjusts a carrier wave frequency fc on the basis of the dq-axis voltage commands Vd* and Vq*, the rotational position θ of the permanent magnet synchronous motor 2, the respective signals of Flagsynasyn, Nc, and fcasyn, the angular velocity ωr, the power supply voltage Hvdc, and the torque command T*, and outputs the carrier wave frequency fc to the carrier wave generation unit 19.
The zero-phase addition unit 18 adds the Mod mode signal output from the pulse pattern determination unit 14 to the three-phase voltage commands Vu*, Vv*, and Vw*, and outputs three-phase voltage commands Vu*′, Vv*′, and Vw*′.
The carrier wave generation unit 19 outputs carrier wave Tr on the basis of the carrier wave frequency fc adjusted by the carrier wave frequency adjustment unit 17.
The PWM control unit 20 adds and subtracts the three-phase voltage commands Vu*′, Vv*′, and Vw*′ output from the zero-phase addition unit 18 and the carrier wave Tr output from the carrier wave generation unit 19, and outputs PWM control signals Gup, Gun, Gvp, Gvn, Gwp, and Gwn.
The motor control device 1 of the present embodiment is configured as described above, and the pulse pattern determination unit 14 determines an optimum pulse pattern capable of performing appropriate PWM control that achieves both low loss and low NV even in a scene where a plurality of surrounding environments and a plurality of vehicle states overlap.
Note that the determination of the optimum pulse pattern in the optimum pulse pattern determination unit 143 in the pulse pattern determination unit 14 to be described later with reference to
The configuration of the pulse pattern determination unit 14 will be described with reference to
As illustrated in
The configuration of each unit of the low loss/low NV evaluation weight determination unit 141, the loss/NV calculation unit 142, and the optimum pulse pattern determination unit 143 will be described later with reference to
The pulse pattern information output unit 144 receives the optimum pulse pattern output from the optimum pulse pattern determination unit 143 as an input, and outputs the pulse pattern as a modulation method, a synchronization/asynchronization flag, the number of carriers, and a carrier frequency. In a case where the synchronization flag is on, the number of carriers is output, and in a case where the asynchronization flag is on, the carrier frequency is output.
The configuration of the low loss/low NV evaluation weight determination unit 141 will be described with reference to
As illustrated in
The evaluation weight a indicates a weight of low loss, the evaluation weight b indicates a weight of low NV, and a sum of a and b is 1. For example, when the weight a of the low loss is maximum, a=1 and b=0.
The evaluation weighting is performed by each of mode designation determination 1411, safety determination 1412, other nuisance determination 1413, and ride comfort/cost evaluation calculation 1414 classified by importance, and is performed by an evaluation weight selection unit 1415 in the priority order of 1411, 1412, 1413, and 1414.
The mode designation determination 1411 is effective in a case where there is an instruction of low loss or low NV from a driver, an automatic driving electronic control unit (ECU), or the like, and for example, the weight becomes a=1 and b=0 in the case of low loss or a=0 and b=1 in the case of low NV.
The safety determination 1412 is effective when in a case where call attention determination is made or a case where battery exhaustion determination is made. In addition, contents related to fail-safe such as protection against high heat of the inverter 3 or the permanent magnet synchronous motor 2 may be included.
The call attention determination is effective, for example, in a case where it is detected that a person is present at a short distance from the person/vehicle detection sensor information, and the presence of a host vehicle is indicated as low loss (high NV) of a=1 and b=0. Examples of the person/vehicle detection sensor here include a laser, a radar, a camera, a beacon, a GPS, and the like.
In addition, in the battery exhaustion determination, for example, the battery exhaustion is determined from the remaining battery amount, and the low loss of a=1 and b=0 is set so as to enable driving to a next chargeable place.
The other nuisance determination 1413 is effective in a case where nuisance to another person is a concern, for example, in a case where another person passes through a residential area at night, and the low NV of a=0 and b=1 is set.
Processing in the ride comfort/cost evaluation calculation 1414 will be described with reference to
As illustrated in
Examples of the low loss/low NV priority information include time, a place (a distance from a residential area), congestion information (congestion distance), a remaining battery amount, power supply voltage, torque, vehicle speed, microphone sound outside the vehicle, an air conditioning level, engine output, an audio volume, the number of passengers, and a loading amount, and each continuous physical value is converted into an evaluation value Vn to be used in the evaluation formula.
Here, the evaluation value Vn is a value corresponding to the evaluation weight a, and the closer to 1, the closer to the low loss, and the closer to 0, the closer to the low NV.
Note that the evaluation value Vn may not be a perfect continuous value, and may be a discrete value (for example, 10 stages) having a tendency of continuity or the like in consideration of implementation in a program or the like. At this time, a relationship between each surrounding environment/vehicle information and the evaluation value Vn may be prepared in advance at the time of design, or may be updated later by OTA or learning.
The evaluation formula is configured by formulas (1) to (3) in
Formula (1) is an offset value aos of the weight, and includes, for example, a driver detail priority setting value ads and an OTA setting value aota. The driver detail priority setting value is an offset value that can be intentionally tuned by the driver, can contribute to further personalization of an automobile, and is set from a setting console of the automobile, a smartphone, or the like. In addition, the OTA setting value aota enables sharing the performance of the same product affected by aging deterioration, and is set by the OTA function.
Formula (2) is the calculation of the low loss weight a, and is a value obtained by multiplying a value (1-aos), which is obtained by subtracting the weight offset value aos from 1, by (ΣVn/ΣVn. max) obtained by balancing low loss and low NV from the surrounding environment/vehicle information. A maximum evaluation value Vn.max in the present embodiment is the maximum value of Vn (1 in the present embodiment).
Formula (3) is the calculation of the low NV weight b, and is a value obtained by subtracting the low loss weight a from 1.
In the present embodiment, although Formula (2) is most simply shown, the value of the maximum evaluation value Vn.max may be changed for each surrounding environment/vehicle information, or a formula with a weight wtn added for each surrounding environment/vehicle information may be used (for example, the second term is (Σ(Vn. wtn)/Σ(Vn.max·wtn)).
In addition, the weight wtn is not a constant value, and may be variable depending on the physical value (each horizontal axis in
In addition, in the present embodiment, the evaluation formula calculation based on the low loss/low NV priority information such as the surrounding environment/vehicle information is performed for the ride comfort and cost. However, also in the mode designation determination 1411, the safety determination 1412, and the other nuisance determination 1413, the low loss and low NV weight may be determined by the evaluation formula calculation within the same degree of importance.
In addition, in the present embodiment, the ride comfort and cost evaluation assuming a passenger car are described, but emphasis may be placed on the number of occupants and the loading amount for buses and trucks.
The function of the loss/NV calculation unit 142 will be described with reference to
As illustrated in
Note that the loss refers to a system loss of the inverter/motor, and the NV refers to harmonic distortion of current or torque. In a case where the inverter/motor temperature is different from the value at the time of analysis, the value of loss/NV is corrected.
In the present embodiment, acceleration forward is targeted, but in a case where the loss and NV differ between acceleration and regeneration, and forward and reverse, the loss and NV are calculated for each.
The function of the optimum pulse pattern determination unit 143 will be described with reference to
As illustrated in
The optimum here means that it is possible to output a pulse pattern that is most appropriate for the surrounding environment and the vehicle state and can meet the low loss and low NV demands of the driver.
The loss w(n) and NV h(n) are converted into low loss Lw(n) and low NV h(n), which are values obtained by normalizing the inverses, by low-loss conversion 1431 and low-NV conversion 1432.
In the optimum pulse pattern determinations 1433a to 1433e (only a and b are illustrated), the evaluation value is calculated for each pulse pattern on the basis of the evaluation formula for the current operating point and the peripheral operating points, and the optimum pulse pattern having the largest evaluation value is determined.
This evaluation formula is (n) evaluation formula=a×Lw(n)l, m+b×Lh(n)l, m.
The function of a variation pulse difference limiting unit 1434 in
As illustrated in
In a case where the surrounding environment or the vehicle state changes at the current operating point and the optimum pulse pattern is changed, or a case where the operating point changes and transitions to a peripheral operating point, the optimum pulse pattern is stored in an optimum pulse pattern storage unit 1434a. In addition, the current pulse pattern is stored in a current pulse pattern storage unit 1434c.
Next, in a next pulse pattern storage unit 1434b, a value at which a variation pulse difference from the current pulse pattern does not become steep between the pulse patterns stored in the optimum pulse pattern storage unit 1434a and the current pulse pattern storage unit 1434c (for example, 2 which is the minimum pulse difference that is not even order) is stored in the next pulse pattern storage unit 1434b.
Then, by waiting for a certain period of time until updating the current pulse pattern to the next pulse pattern (for example, a period of time of 10 sec for human auditory perception to adapt), a noise change due to a rapid change in the number of pulses is suppressed, and the auditory perception is improved. The right diagram of
Note that, in the present embodiment, processing is performed in the ride comfort/cost evaluation calculation 1414. However, in a case where an item regarding safety with higher importance in the low loss/low NV evaluation weight determination unit 141 becomes effective, the variation pulse limitation may not be performed.
In addition, in the present embodiment, the variation pulse difference is limited on the assumption of the synchronous PWM, but the carrier or switching frequency difference may be limited on the assumption of the asynchronous PWM.
As described above, the motor control device 1 of the present embodiment includes: a plurality of PWM pulse patterns; the pulse pattern determination unit 14 that sets a pulse pattern for performing PWM control; the evaluation unit (low loss/low NV evaluation weight determination unit 141) that determines a priority of a total loss of an AC motor (permanent magnet synchronous motor 2) and a power converter (inverter 3) and vibration noise of the AC motor (permanent magnet synchronous motor 2); and the loss/NV calculation unit 142 that calculates a value of the total loss and a value of the vibration noise in torque and rotation speed for each pulse pattern. The evaluation unit (low loss/low NV evaluation weight determination unit 141) determines the priority on the basis of a parameter regarding at least one of a surrounding environment, mode designation by intention of a driver, a remaining battery amount, a driving operation point, and a vehicle state, and the pulse pattern determination unit 14 sets the pulse pattern by using the priority determined by the evaluation unit (low loss/low NV evaluation weight determination unit 141), the value of the total loss, and the vibration noise. Note that the above-described parameters are represented as continuous variables.
Accordingly, it is possible to appropriately achieve both low loss and low NV even in a scene where a plurality of surrounding environments and a plurality of vehicle states overlap.
In addition, the evaluation unit (low loss/low NV evaluation weight determination unit 141) has an evaluation formula for determining the priority, and the evaluation formula includes the driver detail priority setting value.
Accordingly, the low loss/low NV weight determination is offset with the driver detail priority setting value, so that it is possible to set the preferred loss/NV specifications of the driver.
In addition, the evaluation formula may include external update information.
By including the external update information, the weight determination of low loss and low NV is offset with the external update information, whereby the product aggregation information such as aging deterioration can be reflected by the OTA.
In addition, the pulse pattern determination unit 14 sets the pulse pattern at the current operating point and the peripheral operating point in the correlation between the torque and the rotation speed of the permanent magnet synchronous motor 2.
The determination of the pulse pattern that optimizes the low loss and the low NV is performed at the current operating point and the peripheral operating point, so that the pulse pattern can be immediately applied at the time of changing the operating point.
In addition, when changing the pulse pattern, the pulse pattern determination unit 14 limits a variation width such that the variation pulse difference, the carrier frequency difference, and the switching frequency difference before and after the change are equal to or less than predetermined values.
The variation pulse difference is limited by changing the pulse pattern that optimizes the low loss and the low NV, so that it is possible to avoid the deterioration of the auditory perception due to the significant change of the frequency.
An example in which the motor control device 1 described in the first embodiment is mounted on a hybrid system will be described with reference to
As illustrated in
In the present embodiment, the weight determination of low loss and low NV in the hybrid system is performed by an evaluation formula using continuous physical values representing the surrounding environment and the vehicle state.
Accordingly, it is possible to appropriately determine the pulse pattern in a scene in which a plurality of surrounding environments and a plurality of vehicle states overlap and optimize both low loss and low NV.
An example in which the motor control device 1 described in the first embodiment is mounted on a boost converter system will be described with reference to
As illustrated in
In the present embodiment, the weight determination of low loss and low NV in the boost converter system is performed by an evaluation formula using continuous physical values representing the surrounding environment and the vehicle state.
Accordingly, it is possible to appropriately determine the pulse pattern in a scene in which a plurality of surrounding environments and a plurality of vehicle states overlap and optimize both low loss and low NV.
An example in which the motor control device 1 described in the first embodiment is mounted on an electric power steering system will be described with reference to
As illustrated in
In the present embodiment, the weight determination of low loss and low NV in the electric power steering system 61 is performed by an evaluation formula using continuous physical values representing the surrounding environment and the vehicle state.
Accordingly, it is possible to appropriately determine the pulse pattern in a scene in which a plurality of surrounding environments and a plurality of vehicle states overlap and optimize both low loss and low NV.
An example in which the motor control device 1 described in the first embodiment is mounted on an electric brake system will be described with reference to
As illustrated in
In the present embodiment, the weight determination of low loss and low NV in the electric brake system is performed by an evaluation formula using continuous physical values representing the surrounding environment and the vehicle state.
Accordingly, it is possible to appropriately determine the pulse pattern in a scene in which a plurality of surrounding environments and a plurality of vehicle states overlap and optimize both low loss and low NV.
An example in which the motor control device 1 described in the first embodiment is mounted on an in-wheel motor system will be described with reference to
The in-wheel motor system of the present embodiment includes the motor control device 1 (not illustrated), a plurality of inverters that operates on the basis of the PWM pulse signal output from the motor control device 1 and performs power conversion from DC power to AC power, and a plurality of AC motors that are driven by the flow of the AC power generated by the inverters.
In the present embodiment, the weight determination of low loss and low NV in the in-wheel motor system is performed by an evaluation formula using continuous physical values representing the surrounding environment and the vehicle state.
Accordingly, it is possible to appropriately determine the pulse pattern in a scene in which a plurality of surrounding environments and a plurality of vehicle states overlap and optimize both low loss and low NV.
Note that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the described configurations. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/012255 | 3/17/2022 | WO |
