Control device for an electric vehicle

Abstract

Provided is a control device for an electric vehicle, which suppresses a torque variation that occurs with a change in magnetic force of a drive motor, without being affected by the performance of a clutch. A clutch (83) is disposed between a drive motor (3) in which a rotor (33) is provided with a magnetic pole made of a magnetic force variable magnet (35) and a drive wheel (4R). When the vehicle (1) is running, a first clutch control is executed in which the coupling torque of the clutch (83) is controlled to be higher than the requested torque, together with torque control. When the vehicle (1) is running and the magnetic flux control is executed, the first clutch control is changed to a second clutch control in which the coupling torque is made to coincide with the requested torque before the execution of the magnetic flux control, and the micro-slip control in which the clutch (83) is set from the coupled state to the micro-slip state is started by adding a prescribed slip torque to the requested torque.

Description

Technical Field

[0001] The disclosed technology relates to control devices for electric vehicles, hybrid vehicles, and other electric vehicles that can operate using electricity. Background Technology

[0002] Patent Document 1 discloses a hybrid vehicle equipped with a permanent magnet synchronous drive motor. In this drive motor, a variable magnet capable of changing the magnitude of the magnetic force is used for the permanent magnets disposed on the rotor.

[0003] The output range of the drive motor is divided into multiple magnetization regions, and an optimal magnetic force value (optimal magnetic force value) is set for each magnetization region. Moreover, the configuration is such that when the output of the drive motor switches between these magnetization regions, the magnetic force of the variable magnet changes to the optimal magnetic force value of the switching target.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-027615 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] When the magnetic force of the variable magnet is changed, a large magnetizing current (so-called d-axis current) is applied to the stator coils of the drive motor. This interferes with the drive current (so-called q-axis current), causing torque variation. That is, the d-axis current is a component orthogonal to the q-axis current that generates torque. Therefore, this large current itself is not output as torque, but due to its interference with the q-axis current, torque varies.

[0009] If the magnetic force changes to demagnetize, it shifts in the direction of decreasing torque; however, if the magnetic force changes to magnetize, it shifts in the direction of increasing torque. Therefore, when the magnetic force of the variable magnet is changed in the direction of magnetization, a high torque is output from the drive motor. Generally, the clutch connecting the drive motor and the drive wheels has a higher engagement torque than the requested torque, so this torque is transmitted to the drive wheels, thereby generating a torque shock to the moving vehicle, which may cause discomfort to the driver.

[0010] To suppress such torque surges, it is advisable to allow the clutch located between the drive motor and the drive wheels to slip. That is, even if a high torque is output from the drive motor, slipping the clutch can reduce the torque transmitted to the drive wheels, thus mitigating torque surges.

[0011] However, if the clutch slips, a sudden increase in the rotational speed of the drive motor (the so-called "surge") will occur. If this surge is not quickly eliminated, the clutch may be damaged due to the frictional heat caused by the slippage.

[0012] Therefore, the inventors previously proposed a technique to quickly eliminate the surge in drive motor speed associated with clutch slippage (Japanese Patent Application 2021-95825).

[0013] This technology essentially switches from torque control, which aims to control the requested output torque, to power control, which aims to control the output power, when slippage occurs in the clutch due to magnetization. This allows the rotational speed to converge along with the output torque, quickly eliminating any spikes in the drive motor's torque output.

[0014] (The problem of the difference in the friction coefficient of the clutch)

[0015] Generally, the dynamic friction coefficient (μd) of the clutch is set to be at the same level as the static friction coefficient (μs). Therefore, even if the friction coefficient changes when the clutch is engaged, almost no torque shock is generated. Thus, there are no problems in the previously proposed technology.

[0016] However, depending on the clutch, the dynamic friction coefficient may sometimes be lower than the static friction coefficient, and the difference may be significant. In such cases, even with the previously proposed technology, a torque shock caused by the difference in friction coefficients may occur during clutch engagement, resulting in discomfort for the driver.

[0017] In the technology disclosed here, torque fluctuations caused by changes in the magnetic force of the drive motor are suppressed without being affected by the performance of the clutch.

[0018] Methods for solving problems

[0019] The disclosed technology relates to a control device for an electric vehicle capable of operating using electricity, the electric vehicle having a drive motor whose rotor has magnetic poles composed of a magnetically variable magnet capable of changing magnetic force and a clutch disposed between the drive motor and the drive wheel.

[0020] When the electric vehicle is in motion, the control device performs torque control to control the motor torque output by the drive motor to be consistent with the requested torque to be output to the drive wheel, and simultaneously performs first clutch control to control the engagement torque of the clutch to be higher than the requested torque.

[0021] Furthermore, when the electric vehicle is in motion, when magnetization control is executed to change the magnetic force of the variable magnetic magnet in the magnetization direction, before executing the magnetization control, the first clutch control is changed to a second clutch control that makes the engagement torque consistent with the requested torque, and a micro-slip control is started to set the clutch from the engagement state to the micro-slip state by adding a predetermined slip torque to the requested torque based on the dynamic friction coefficient and static friction coefficient of the clutch.

[0022] That is, according to this control device, similar to the previously proposed technology, when magnetization control is performed while the electric vehicle is in motion, the control switches from the first clutch control to the second clutch control, which matches the engagement torque with the requested torque, before the magnetization control is performed. Therefore, clutch slippage can suppress torque surges caused by magnetization.

[0023] Furthermore, by adding a specified slip torque to the requested torque based on the clutch's dynamic and static friction coefficients, micro-slip control is initiated to set the clutch from the engaged state to a micro-slip state.

[0024] That is, when the clutch speed difference increases rapidly during the timing of the magnetization control, instead of switching the clutch from the engaged state to the disengaged state, a predetermined slip torque is added to the requested torque beforehand, switching the clutch from the engaged state to a slightly slipping state. This allows the friction coefficient to be switched from the static friction coefficient to the dynamic friction coefficient in advance even under conditions of small speed difference, thus suppressing torque shocks caused by friction coefficient differences.

[0025] Therefore, according to this control device, torque fluctuations caused by changes in the magnetic force of the drive motor can be suppressed without being affected by the performance of the clutch.

[0026] Alternatively, at the start of the micro-slip control, a transition control is performed to adjust the hydraulic pressure of the clutch so that the torque change caused by the clutch changing from the engaged state to the micro-slip state is offset.

[0027] At the start of micro-slip control, the clutch transitions from an engaged state to a micro-slip state. Although the timing of this transition is smaller than that of magnetization control, it still produces a torque change caused by the difference in the clutch's friction coefficient.

[0028] Unlike magnetization control, where the output torque is irregular and difficult to determine in advance, the sliding torque added or subtracted in micro-slip control is preset. Furthermore, the torque change resulting from the switching of the friction coefficient at the start of micro-slip control is determined based on this sliding torque, so even hydraulic control with poor responsiveness can be adjusted according to this torque change.

[0029] Therefore, by setting conditions for hydraulic control that can counteract the torque variation and adjusting the hydraulic pressure (pressing force) of the clutch accordingly, it is also possible to suppress the slight torque shock generated at the start of micro-slip control.

[0030] Alternatively, during the execution of the micro-slip control, instead of the torque control, power control is performed to control the motor torque so that the power output from the drive wheel matches a predetermined target power value.

[0031] Unlike torque control, which only follows the rotational speed, power control can balance both rotational speed and torque. Therefore, during the execution of micro-slip control, the torque and rotational speed of the drive motor can be balanced, stably converging to a micro-slip state.

[0032] Alternatively, after the magnetization control is executed, feedback control is performed based on the difference between the speed on the input side and the speed on the output side of the clutch, and the power control is executed to converge to the micro-slip state.

[0033] In this way, it can quickly converge to the micro-sliding state.

[0034] Alternatively, at the end of the micro-slip control, a transition control is performed to adjust the hydraulic pressure of the clutch so that the torque change caused by the clutch changing from the micro-slip state to the engaged state is offset.

[0035] This also allows for the suppression of the slight torque shock generated at the end of micro-slip control. As a result, the magnetic force of the drive motor can be changed with virtually no shock.

[0036] Invention Effects

[0037] According to the disclosed technology, torque variations caused by changes in the magnetic force of the drive motor can be suppressed without being affected by the performance of the clutch. Attached Figure Description

[0038] Figure 1 It is a schematic diagram showing the main structure of a car that applies the disclosed technology.

[0039] Figure 2 This is a schematic cross-sectional view showing the structure of the drive motor.

[0040] Figure 3 It is a block diagram representing the MCU and its main associated input / output devices.

[0041] Figure 4 This is a diagram illustrating the output range of a drive motor.

[0042] Figure 5 It is a simplified representation of a system diagram related to the control of the drive motor.

[0043] Figure 6 This is a flowchart illustrating an example of controlling a drive motor.

[0044] Figure 7 This is a flowchart illustrating the main processing flow of magnetic force change control.

[0045] Figure 8 This is a diagram used to illustrate the generation of torque shocks.

[0046] Figure 9 This is a block diagram representing the TCU and its associated main input / output devices.

[0047] Figure 10 This is a graph used to illustrate the phenomenon of price spikes.

[0048] Figure 11 This diagram is used to illustrate the problem of the difference in friction coefficients between transmission clutches.

[0049] Figure 12 It is a timing diagram of the main parameters before and after applying the disclosed technology to magnetization control.

[0050] Figure 13 It means and Figure 12 A flowchart of an example of the corresponding control.

[0051] Figure 14 It is following closely Figure 13 The following flowchart.

[0052] Explanation of reference numerals in the attached figures

[0053] 1. Automobiles (electric vehicles)

[0054] 2 engines

[0055] 3 drive motors

[0056] 4R drive wheels

[0057] 5. Relay Clutch

[0058] 8-speed transmission

[0059] 10 batteries

[0060] 20. Engine Control Unit (ECU)

[0061] 21. Motor Control Unit (MCU)

[0062] 21a Motor Output Control Unit

[0063] 21b Magnetization Control Section

[0064] 22. Transmission Control Unit (TCU)

[0065] 22a Relay Clutch Control Unit

[0066] 22b Transmission Clutch Control Unit

[0067] 23. Brake Control Unit (BCU)

[0068] 24. General Control Unit (GCU)

[0069] 33 rotors

[0070] 34 stator

[0071] 35 Magnets (Variable Magnetic Force)

[0072] 80 input axis

[0073] 81 output shaft

[0074] 82 Planetary Gear Mechanism

[0075] 83 transmission clutch

[0076] 83a input side

[0077] 83b output side Detailed Implementation

[0078] The disclosed technology will now be described. However, the following description is merely illustrative in nature.

[0079] <Electric Vehicles>

[0080] Figure 1 The diagram shows a car 1 (an example of an electric vehicle) employing the disclosed technology. This car 1 is a hybrid vehicle capable of operating on electricity. The drive source of car 1 includes an engine 2 and a drive motor 3. These work together to drive two of the four wheels 4F, 4F, 4R, 4R, positioned symmetrically from left to right (drive wheels 4R). Thus, car 1 moves. Alternatively, car 1 can also be an electric vehicle equipped only with the drive motor 3. Car 1 can also be a four-wheel drive vehicle.

[0081] In the case of vehicle 1, engine 2 is located at the front of the vehicle body, and drive wheels 4R are located at the rear of the vehicle body. That is, vehicle 1 is a so-called FR (front-engine, rear-wheel drive) vehicle. Moreover, in the case of vehicle 1, as a drive source, engine 2 is the main body, while drive motor 3 is used to assist in driving engine 2 (a so-called mild hybrid system). In addition, drive motor 3 not only serves as a drive source, but also functions as a generator during regeneration.

[0082] In automobile 1, in addition to the engine 2 and drive motor 3, the drive system also includes a relay clutch 5, an inverter 6, a transmission 8, a differential gear 9, and a battery 10. Furthermore, the control system in automobile 1 includes an engine control unit (ECU) 20, a motor control unit (MCU) 21, a transmission control unit (TCU) 22, a brake control unit (BCU) 23, and a general control unit (GCU) 24. An engine rotation sensor 50, a motor rotation sensor 51, a current sensor 52, a magnetic force sensor 53, an accelerometer sensor 54, and a transmission sensor 55 are also installed in automobile 1 along with the control system components.

[0083] (Drive system device)

[0084] Engine 2 is, for example, an internal combustion engine that uses gasoline as fuel for combustion. Alternatively, engine 2 is a so-called four-stroke engine that generates rotational power by repeatedly cycling through intake, compression, expansion, and exhaust. Engine 2 can be of various types and forms, such as diesel engines, but in the disclosed technology, there are no particular limitations on the type and form of the engine.

[0085] In this automobile 1, the output shaft of the engine 2, which outputs rotational power, is positioned approximately at the center of the vehicle in the width direction, facing the front-rear direction of the vehicle body. The automobile 1 includes various devices or mechanisms attached to the engine 2, such as an intake system, an exhaust system, and a fuel supply system, but their illustrations and descriptions are omitted.

[0086] The drive motor 3 is arranged in series behind the engine 2 via a relay clutch 5. The drive motor 3 is a permanent magnet type synchronous motor driven by three-phase AC. Figure 2 As shown in the simplified diagram, the drive motor 3 is roughly composed of a motor housing 31, a shaft 32, a rotor 33, a stator 34, etc.

[0087] The motor housing 31 is a container with a cylindrical space inside which the front and rear ends are closed, and is fixed to the body of the automobile 1. The rotor 33 and the stator 34 are housed in the motor housing 31. The shaft 32 is rotatably supported by the motor housing 31 with its front and rear ends protruding from the motor housing 31 respectively.

[0088] The relay clutch 5 is provided between the front end of the shaft 32 and the output shaft of the engine 2. The relay clutch 5 is configured to switch between a state in which the output shaft of the engine 2 is connected to the shaft 32 (connected state) and a state in which the output shaft of the engine 2 is disconnected from the shaft 32 (disconnected state).

[0089] The rear end of shaft 32 is connected to the input shaft 80 of transmission 8. Alternatively, a second relay clutch may be provided between shaft 32 and the input shaft 80 of transmission 8.

[0090] The rotor 33 is a cylindrical component consisting of multiple metal plates stacked together, each having a central shaft hole. The rotor 33 is integrated with the shaft 32 by fixing the middle portion of the shaft 32 into the shaft hole of the rotor 33.

[0091] Magnets 35 are arranged around the entire circumference of the rotor 33. The magnets 35 are configured to have different magnetic poles, namely S poles and N poles, arranged alternately at equal intervals in the circumferential direction. The magnets 35 can be composed of a cylindrical magnet with multiple magnetic poles, or they can be composed of multiple arc-shaped magnets that constitute each magnetic pole.

[0092] In this drive motor 3, the magnet 35 is also configured to change the magnitude of the magnetic force (magnetic force variable magnet 35). Typically, such drive motors 3 use magnets with high coercivity (diamagnetic force) and the ability to maintain the magnetic force for a long time (permanent magnets). In this drive motor 3, a permanent magnet with low coercivity is used as the magnetic force variable magnet 35 so that the magnetic force can be changed more easily.

[0093] Permanent magnets come in various types, such as ferrite magnets, neodymium magnets, samarium cobalt magnets, and AlNiCo magnets, and their coercivity also varies. The type and material of the variable magnetic force magnet 35 can be selected according to specifications without any particular restrictions.

[0094] A cylindrical stator 34 (inner rotor type) is arranged around the rotor 33 with tiny gaps (voids). The stator 34 has a stator core 34a formed by stacking multiple metal plates and multiple coils 36 formed by winding wires on the stator core 34a.

[0095] Multiple teeth 34b are provided on the stator core 34a, extending radially inward. Multiple coils 36 are formed by winding wires on these teeth 34b in a predetermined order. These coils 36 constitute a three-phase coil group consisting of U-phase, V-phase and W-phase.

[0096] In order to energize the coil groups of each phase, connecting cables 36a are led out from the coil groups of each phase to the outside of the motor housing 31. These connecting cables 36a are connected to the on-board battery 10, which serves as the drive power source, via the inverter 6. In the case of this vehicle 1, the battery 10 is a DC battery with a rated voltage of 50V or less, specifically 48V.

[0097] Battery 10 supplies DC power to inverter 6. Inverter 6 converts the DC power into three-phase AC power to power drive motor 3. As a result, rotor 33 is driven to rotate, and the power (rotational power) of drive motor 3 is output to gearbox 8 via shaft 32.

[0098] In the case of car 1, transmission 8 is a multi-gear automatic transmission (so-called AT). For example... Figure 1 As shown, the transmission 8 has an input shaft 80 at one end, which is connected to the drive motor 3 (shaft 32). At the other end of the transmission 8 is an output shaft 81 that rotates independently of the input shaft 80. Between these input shafts 80 and output shafts 81, a transmission mechanism consisting of a hydraulic torque converter 84, multiple planetary gear mechanisms 82, and multiple transmission clutches 83 (including brakes) is assembled.

[0099] By switching these transmission mechanisms, the transmission can be configured to switch forward or backward, or to change to different speeds between the input shaft 80 and the output shaft 81 of the transmission 8, i.e., to switch the gear ratio.

[0100] For example, the input side 83a of each transmission clutch 83 is configured to be connected to the input shaft 80 via a torque converter 84. The output side 83b of each transmission clutch 83 is connected to the output shaft 81 via a corresponding planetary gear mechanism 82. Furthermore, if a specific transmission clutch 83 is selected and engaged, the input shaft 80 and output shaft 81 of the transmission are connected via that transmission clutch 83 and its corresponding planetary gear mechanism 82. This allows for switching of gear ratios, etc.

[0101] The output shaft 81 is connected to the differential gear 9 via a drive shaft 11 that extends along the longitudinal direction of the vehicle body and is coaxially arranged with the output shaft 81. A pair of drive shafts 13 are connected to the differential gear 9, extending along the width direction and connected to the left and right drive wheels 4R. The rotational power output through the drive shaft 11 is distributed by the differential gear 9 and then transmitted to each drive wheel 4R via these drive shafts 13. Brakes 14 are installed on each wheel 4F, 4F, 4R, 4R to brake its rotation.

[0102] (The device controlling the system)

[0103] In vehicle 1, the aforementioned ECU20, MCU21, TCU22, BCU23, and GCU24 are provided to control the vehicle's movement according to the driver's input. These units consist of hardware such as processors, memory, and interfaces, and software such as databases and control programs. These units are connected, for example, via CAN (Controller Area Network) to enable electrical communication with each other.

[0104] ECU20 is the main unit controlling the operation of engine 2. MCU21 is the main unit controlling the operation of drive motor 3. TCU22 is the main unit controlling the operation of transmission 8. BCU23 is the main unit controlling the operation of brake 14. GCU24 is a higher-level unit that is electrically connected to these ECU20, MCU21, TCU22, and BCU23 and performs integrated control over them.

[0105] The "control device" in the disclosed technology is composed of these units. In particular, the MCU21, which mainly controls the operation of the drive motor 3, and the TCU22, which mainly controls the operation of the transmission 8, constitute the main body of the control device. Through the cooperation of these units, micro-sliding control, etc., described later, are performed.

[0106] An engine rotation sensor 50 is installed on the engine 2, detects the engine speed of the engine 2, and outputs the speed to the ECU 20. A motor rotation sensor 51 is installed on the drive motor 3, detects the speed and rotational position of the drive motor 3, and outputs the speed to the MCU 21. A current sensor 52 is installed on the connecting cable 36a, detects the current value energized to each coil 36, and outputs the current value to the MCU 21.

[0107] A magnetic sensor 53 is mounted on the drive motor 3, detects the magnetic force of the variable magnet 35, and outputs it to the MCU 21. An accelerator sensor 54 is mounted on the accelerator pedal (accelerator pedal 15) pressed by the driver when driving the car 1, detects the accelerator opening degree corresponding to the output required for driving the car 1, and outputs it to the ECU 20. A transmission sensor 55 detects the rotational speed and engagement torque of each transmission clutch 83, the rotational speed of the output shaft 81, etc., and outputs them to the TCU 22.

[0108] Based on the signals from the detected values ​​input from these sensors, each unit cooperates to control the various devices of the drive system, thereby enabling the vehicle 1 to move. For example, when the vehicle 1 is moving by the driving force of the engine 2, the ECU 20 controls the operation of the engine 2 based on the detected values ​​from the accelerometer sensor 54 and the engine rotation sensor 50.

[0109] Furthermore, TCU22 controls the relay clutch 5 to engage, and switches the transmission mechanism of the gearbox 8 according to the driving state of the vehicle 1. When the vehicle 1 brakes, BCU23 controls each brake 14. During regenerative braking, TCU22 controls the relay clutch 5 to disengage or partially engage, and engages the designated transmission clutch 83 of the gearbox 8. In this way, MCU21 controls the power generation using the drive motor 3 and recovers its power from the battery 10.

[0110] <Control of drive motor>

[0111] The MCU21 controls the vehicle 1 to use the power output of the drive motor 3 for driving, either when the drive motor 3 is outputting power independently or when the output of the engine 2 is assisted as needed.

[0112] Specifically, ECU20 sets the torque output by engine 2 based on the detection values ​​of accelerometer sensor 54, engine rotation sensor 50, etc. Simultaneously, GCU24 sets the requested torque amount (requested torque) for drive motor 3 within a specified output range according to a pre-set output distribution ratio between engine 2 and drive motor 3. MCU21 controls drive motor 3 to output this requested torque.

[0113] Figure 3 The diagram shows the MCU 21 and its associated main input / output devices. Within the MCU 21, as functional structures, a motor output control unit 21a and a magnetization control unit 21b are provided through hardware and software. The motor output control unit 21a has the function of controlling the drive of the drive motor 3, and causes the drive motor 3 to output the requested power by controlling the drive current flowing into the coil 36.

[0114] On the other hand, the magnetization control unit 21b has the function of improving the power factor of the drive motor 3 by controlling the magnetization current flowing into the coil 36 to change the magnetic force of the variable magnet 35. Specifically, the magnetic force of the variable magnet 35 is changed so that the magnetic force of the variable magnet 35 is approximately the same as the electromagnetic force generated in the coil 36 by the drive current.

[0115] Power factor refers to the ratio of active power (actually consumed electricity) to apparent power (electricity supplied to drive motor 3). If the power factor is low, a large current needs to be applied to achieve the same output, thus requiring a larger motor. Therefore, by improving the power factor of drive motor 3, it is possible to make drive motor 3 lightweight and compact. In addition, a high power factor can also increase the power generation during regeneration.

[0116] (Output range of the drive motor)

[0117] exist Figure 4 The output range of drive motor 3 is illustrated below. The output range is defined by the upper load line, which represents the upper limit of torque (load) at each speed.

[0118] Specifically, in the low-speed region before the specified rotational speed (r1), the upper limit of torque remains at its maximum (T2). In the medium-speed and high-speed regions where the rotational speed is higher than that in the low-speed region, the upper limit of torque gradually decreases until the rotational speed reaches its upper limit (r2).

[0119] In MCU21, there is pre-set data such as graphs or tables that define such output ranges. Motor output control unit 21a controls drive motor 3 within this output range by referring to this data.

[0120] Furthermore, the output range of the drive motor 3 is divided into multiple magnetization regions. The magnetization control unit 21b is configured to change the magnetic force of the variable magnet 35 according to each of these magnetization regions.

[0121] like Figure 4 As shown, in this embodiment, the output range of the drive motor 3 is divided into four magnetization regions Rm, from the first to the fourth. Specifically, it is divided into: a first magnetization region Rm1 with high load, which is biased towards the low rotation side and contains the maximum torque T2; a second magnetization region Rm2, which extends from the low rotation side to the high rotation side, and is at a lower load compared to the first magnetization region Rm1, and has a peak torque during medium rotation; a third magnetization region Rm3, which is at a lower load compared to the second magnetization region Rm2, and the peak torque shifts towards the high rotation side; and a fourth magnetization region Rm4, which is at a lower load compared to the third magnetization region Rm3, and contains the torque T1 of the drive motor 3 during idling (torque that does not help the driving of the vehicle 1).

[0122] In each of the magnetization regions Rm, an optimal magnetic force value (optimal magnetic force value) is set to achieve high power factor corresponding to its respective output. For example, in the first magnetization region Rm1, the magnetic force of the variable magnetic force magnet 35 in its initial state is set to the optimal magnetic force value (first optimal magnetic force value). In the second magnetization region Rm2, a lower optimal magnetic force value (second optimal magnetic force value) is set. Furthermore, in the third magnetization region Rm3, a lower optimal magnetic force value (third optimal magnetic force value) is set, and in the fourth magnetization region Rm4, a lower optimal magnetic force value (fourth optimal magnetic force value) is set.

[0123] The magnetization control unit 21b predicts the optimal magnetization region Rm based on the operating state of the vehicle 1. When the magnetization region Rm transitions to another adjacent magnetization region Rm, the magnetic force of the variable magnet 35 is changed to the optimal magnetic force value corresponding to that magnetization region Rm. For example, when transitioning from a first magnetization region Rm1 to a second magnetization region Rm2, demagnetization processing is performed in the drive motor 3, and the magnetic force of the variable magnet 35 is changed from the first optimal magnetic force value to the second optimal magnetic force value.

[0124] For example, when switching from the third magnetization region Rm3 to the second magnetization region Rm2, a magnetization process is performed in the drive motor 3, and the magnetic force of the variable magnetic magnet 35 changes from the third optimal magnetic force value to the second optimal magnetic force value.

[0125] (Specific examples of drive motor control)

[0126] Figure 5 A simplified system diagram related to the control of drive motor 3 is shown in the figure. Figure 6 The diagram illustrates an example of the control of drive motor 3 performed by MCU21. The specific control flow of drive motor 3 will be explained with reference to this. Furthermore, the torque current command Iq is used... ＊ and excitation current command Id ＊ Vector control is used to control the drive motor 3.

[0127] If the car 1 becomes drivable, the MCU 21 continuously receives detection values ​​from the current sensor 52, the motor rotation sensor 51, and the magnetic force sensor 53 (step S1). Similarly, the ECU 20 continuously receives detection values ​​from the accelerometer sensor 54 and the engine rotation sensor 50.

[0128] The GCU24 obtains the detection value from the accelerometer sensor 54 from the ECU20, and sets the torque requested from the drive motor 3 (requested torque) in the torque output to the drive wheel 4R according to the preset output distribution ratio between the engine 2 and the drive motor 3. The GCU24 outputs a command (torque command value T) to the MCU21 to output this requested torque. ＊ ).

[0129] That is, in MCU21, the output of drive motor 3 is controlled based on a specified target torque (so-called torque control). Through torque control, the torque output by drive motor 3 (motor torque) is controlled to match the target torque. Therefore, if the above command is input while the car 1 is driving, MCU21 controls drive motor 3 with the requested torque as the target torque. Through the torque control of drive motor 3, car 1 drives according to the driver's request.

[0130] Furthermore, when the vehicle 1 is in motion, as described above, torque control is interrupted when the magnetization region Rm is switched, and control (magnetic force change control) is performed to apply a high voltage to the coil 36 of the drive motor 3. Through magnetic force change control, the magnetic force of the magnetically variable magnet 35 is changed.

[0131] Specifically, if the torque command value T is input ＊ (If "Yes" is selected in step S2), then MCU21 (motor output control unit 21a) executes a command (drive current command value Idq) to output the change in the drive current (torque current component) that generates the torque. ＊ The calculation and processing of ) (step S3). In addition, MCU21 (magnetization control unit 21b) executes a command (magnetization state command value Φ) that outputs the optimal magnetic force value corresponding to the appropriate magnetization region Rm. ＊ The magnetization control unit 21b performs calculations based on the magnetization state command value Φ (step S4). ＊ The command executes to output a torque current component (magnetic current command value Idq) that corresponds to the change in magnetic force of the variable magnetic magnet 35. ＊ ) operation processing (step S5).

[0132] The MCU21 uses the calculated drive current command value Idq ＊ and magnetic current command value Idq ＊ The system determines whether it is necessary to change the magnetic force of the variable magnet 35 (step S6). For example, as described above, if the magnetization region Rm changes to another magnetization region Rm after the requested torque is output, it is determined that it is necessary to change the magnetic force of the variable magnet 35. If the magnetization region Rm is the same even when the requested torque is output, it is determined that it is not necessary to change the magnetic force of the variable magnet 35.

[0133] Furthermore, if the MCU21 determines that it is not necessary to change the magnetic force of the variable magnetic magnet 35, it determines whether the output torque is greater than the idling torque T1 of the drive motor 3 (step S7). If the output torque is greater than the torque T1, the MCU21 controls the drive motor 3 using normal vector control.

[0134] That is, the motor output control unit 21a executes the command (voltage command value Vuvw) output for PWM control based on the detection values ​​of the current sensor 52 and the motor rotation sensor 51 through current control. ＊ The calculation and processing of the operation are performed (step S8). Then, the operation switch command value is controlled by PWM (step S9).

[0135] The switching command value is output to the inverter 6 through the drive circuit, thereby controlling the on / off state of multiple switching elements inside the inverter 6. As a result, a specified three-phase AC (drive current) is supplied to each coil group, causing the drive motor 3 to rotate at the requested torque (step S10).

[0136] On the other hand, when the MCU21 determines that it is necessary to change the magnetic force of the magnetic variable magnet 35 (no in step S6), the magnetization control unit 21b performs magnetic force change control (step S11).

[0137] Furthermore, even if it is determined that there is no need to change the magnetic force of the variable magnetic force magnet 35, if it is determined that the output torque is less than or equal to the torque T1 of the drive motor 3 during idling (in step S7, it is "No"), the MCU 21 will still perform magnetic force change control through the magnetization control unit 21b (step S11).

[0138] That is, when the demand for rotational power from the drive motor 3 is nearly zero, the magnetically variable magnet 35 changes (resets) its magnetic force to its initial state. In the case of the car 1, for example, sometimes the accelerator pedal 15 is suddenly pressed from an idle or stopped state to accelerate rapidly.

[0139] In the case of the variable magnetic force magnet 35, since the magnetic force in the initial state is set high according to the high load, the drive motor 3 can be properly driven even under such rapid acceleration by resetting the magnetic force during idling.

[0140] Figure 7 The main processing flow for magnetic force change control is shown in the diagram. If magnetic force change control is requested, the magnetization control unit 21b performs the magnetization state command based on the magnetization state command value Φ. ＊ The direction of the magnetization process is determined. That is, it is determined whether to perform a process that increases the magnetic force of the variable magnet 35 (magnetization process) or a process that decreases the magnetic force of the variable magnet 35 (demagnetization process). The magnetization control unit 21b also determines the amount of change in the magnetic force.

[0141] Then, based on the detection value of the motor rotation sensor 51, the magnetization control unit 21b determines whether the position (position in the rotation direction) of the rotor 33 relative to the stator 34 is in a suitable position for magnetization processing (step S21). When the rotor 33 is in an appropriate position, it outputs a magnetization current (step S22). The magnetization current is a pulsed current that generates an electromagnetic force greater than the coercivity of the variable magnet 35. In the magnetization and demagnetization processes, the directions of the magnetic field lines are opposite.

[0142] Magnetization control unit 21b determines whether the magnetic force of the variable magnet 35 matches the magnetization state command value Φ. ＊The indicated optimal magnetic force value is approximately the same (step S23), and magnetization is performed until the magnetic force of the variable magnetic force magnet 35 becomes approximately the same as the optimal magnetic force value. If the magnetic force of the variable magnetic force magnet 35 is reset, magnetization is performed until it becomes approximately the same as the initial magnetic force.

[0143] Then, if the magnetic force of the variable magnet 35 becomes approximately the same as its optimal or initial value, the magnetic force change control ends. Figure 6 As shown, the drive motor 3 is controlled by conventional vector control (steps S8 to S10).

[0144] <Clutch slippage>

[0145] As described above, in this vehicle 1, magnetic force change control is also performed while the vehicle 1 is in motion. If magnetic force change control (magnetization control) is performed in the direction of magnetization during the movement of the vehicle 1, it may generate a torque shock to the moving vehicle 1, causing discomfort to the driver.

[0146] exist Figure 8 The diagram above illustrates the time-dependent change in motor torque Tm during magnetization control. In this example, magnetization is performed during the period t1 to t1'. The period t1' to t2 is as follows: the change in magnetic force is confirmed, and a learning control (learning control) is performed to make the drive current value (q-axis current value) correspond to the magnetized magnetic force, so that the motor torque Tm matches the requested torque. The learning control is a control accompanying magnetization and is included in the magnetization control. Ta is the requested torque. During the operation of vehicle 1, because torque control is performed on drive motor 3, the motor torque Tm before the magnetization control is executed matches the requested torque Ta.

[0147] Tt is the clutch engagement torque in the transmission 8. The clutch engagement torque Tt is the engagement torque of the transmission clutch 83 that connects the input shaft 80 and output shaft 81 of the transmission 8, and is equivalent to the torque that the transmission clutch 83 can transmit to its output side 83b. In order to reliably transmit the motor torque Tm to the drive wheel 4R, the clutch engagement torque Tt is typically controlled (first clutch control) to become a value higher than the requested torque Ta.

[0148] During magnetization control, a magnetizing current (d-axis current) is passed through coil 36 to generate a large electromagnetic force. This results in a voltage significantly higher than the drive voltage being applied to the drive motor 3. Therefore, as... Figure 8 As shown in the diagram above, during magnetization control, the drive motor 3 outputs a peak-shaped high motor torque Tm that significantly exceeds the requested torque Ta. This can result in a torque shock to the moving vehicle 1, causing discomfort to the driver.

[0149] Therefore, in order to suppress such torque shocks, in this vehicle 1, the MCU21, in conjunction with the TCU22, causes the transmission clutch 83 to slip during magnetization control (including the accompanying learning control). Specifically, this is controlled in a manner that makes the clutch engagement torque Tt match the requested torque Ta (second clutch control).

[0150] Figure 9 The diagram shows the TCU22 and its associated main input / output devices. Within the TCU22, as a functional structure, a relay clutch control unit 22a and a transmission clutch control unit 22b are provided through their hardware and software. The relay clutch control unit 22a controls the operation of the relay clutch 5. The transmission clutch control unit 22b controls the operation of each of the transmission clutches 83. The first clutch control and the second clutch control are performed by the transmission clutch control unit 22b.

[0151] If the transmission clutch control unit 22b obtains information related to the execution of magnetic force change control from the GCU 24, it controls the operation of the transmission clutch 83 accordingly. Specifically, as follows... Figure 8 As shown in the figure below, the transmission clutch control unit 22b switches from first clutch control to second clutch control before the start of magnetization control (time t1) (time t0). This reduces the clutch engagement torque Tt. As a result, the transmission clutch 83 slips.

[0152] At this point, the clutch engagement torque Tt is controlled to match the requested torque. By executing the second clutch control, even if a high motor torque Tm is output from the drive motor 3, the torque exceeding the requested torque is not transmitted to the drive wheel 4R. As a result, torque surges caused by magnetization can be suppressed.

[0153] <Problems and Solutions in Second Clutch Control>

[0154] If the transmission clutch 83 is allowed to slip, a phenomenon known as a "surge" will occur in the rotation of the drive motor 3.

[0155] Figure 10 The diagram illustrates the relationship between the motor torque Tm and motor speed Rm during magnetization control. Furthermore, since the output of engine 2 is not considered here, the motor speed Rm is also the speed of the input shaft 80 of the transmission 8. Additionally, the motor torque Tm is equivalent to the torque input to the transmission 8 (torque on the input side 83a of the transmission clutch 83: transmission input torque). The clutch engagement torque Tt, because it is controlled to match the requested torque, is equivalent to the torque output from the transmission 8 (torque on the output side 83b of the transmission clutch 83: transmission output torque).

[0156] Before the magnetization control is executed, the drive motor 3 rotates at a predetermined speed Ra. At this time, because the transmission clutch 83 is engaged, both the input side 83a and the output side 83b of the transmission clutch 83 rotate at speed Ra. Furthermore, the output shaft 81 of the transmission 8 rotates at a speed obtained by the planetary gear mechanism 82 corresponding to the transmission clutch 83.

[0157] like Figure 10 As shown, if the transmission clutch 83 is allowed to slip during magnetization control, the drive motor 3 enters an idling state. Therefore, the motor speed Rm increases abruptly from the speed Ra corresponding to the requested torque Ta. This increase further occurs during learning control, causing the motor speed Rm to remain persistently high. If this surge is not quickly eliminated, the transmission clutch 83 may be damaged due to frictional heat caused by slippage.

[0158] Furthermore, in torque control, the motor torque Tm is controlled to match the target torque (requested torque Ta) based on the current speed. Therefore, after the speed increases due to the spike phenomenon, it becomes a state of maintaining that speed. That is, the spike phenomenon cannot be eliminated by conventional torque control alone.

[0159] As a quick way to eliminate the surge phenomenon, one could consider immediately increasing the clutch engagement torque Tt to match the requested torque Ta after the magnetization control. Because slippage is reduced, the motor speed Rm decreases, thus eliminating the surge phenomenon. However, this will, due to its reaction, transmit a high motor torque Tm to the drive wheel 4R, resulting in a torque surge.

[0160] Alternatively, as a countermeasure, one could consider immediately after the magnetization control to make the target torque in the torque control less than the requested torque Ta, thereby reducing the motor torque Tm itself. This would eliminate the spike phenomenon because the motor speed Rm decreases.

[0161] However, this results in a situation where the motor speed Rm is lower than the initial speed Ra. In this case, even after the spike disappears, if the motor torque Tm is restored to the requested torque through torque control, the motor speed Rm will not return to its initial state. This may cause discomfort to the driver due to insufficient power from drive motor 3.

[0162] Therefore, in the previously proposed technology, the following design was made: power control based on the power output from the drive motor 3 to control the motor torque Tm was performed after the magnetization control, so that the torque and speed output by the drive motor 3 could converge in advance. However, in this technology, it was found that torque shocks might occur due to the performance of the transmission clutch 83, causing discomfort to the driver, and there is room for improvement.

[0163] <The problem of friction coefficient difference between transmission clutches>

[0164] Generally speaking, the dynamic friction coefficient (μd) of the transmission clutch 83 is set to be at the same level as the static friction coefficient (μs).

[0165] When the transmission clutch 83 is engaged, the coefficient of friction switches from the dynamic friction coefficient to the static friction coefficient. If the dynamic friction coefficient and the static friction coefficient are at the same level, no torque shock that would cause discomfort to the driver will be generated when the transmission clutch 83 is engaged with magnetization control. Therefore, there is no problem with the previously proposed technology.

[0166] However, depending on the transmission clutch 83, sometimes the dynamic friction coefficient may be lower than the static friction coefficient, and the difference may be significant. In such cases, even in the previously proposed technology, torque shocks may occur when the transmission clutch 83 is engaged with magnetization control, causing discomfort to the driver.

[0167] Regarding this point, refer to Figure 11 Please provide a detailed explanation. Figure 11 The figure below shows the time-dependent change in the speed difference between the input side 83a and the output side 83b of the transmission clutch 83, with magnetization control starting at t1. When there is a difference between the dynamic and static friction coefficients of the transmission clutch 83, torque control can be considered using either a control that matches the dynamic friction coefficient (μd matching control) or a control that matches the static friction coefficient (μs matching control).

[0168] Figure 11 The above diagram represents μd matching control. Figure 11 The diagrams in the figure represent μs matching control. In these diagrams, the dashed line corresponds to the transmission input torque Tm, and the solid line corresponds to the transmission output torque Tt. In μd matching control, since control is based on the dynamic friction coefficient (μd), the target transmission input torque Tm is the value obtained by multiplying the hydraulic pressure (pressing force) acting on the transmission clutch 83 by the dynamic friction coefficient. On the other hand, in μs matching control, since control is based on the static friction coefficient (μs), the target transmission input torque Tm is the value obtained by multiplying the hydraulic pressure (pressing force) acting on the transmission clutch 83 by the static friction coefficient.

[0169] In μd matching control, if the transmission clutch 83 begins to slip upon the initiation of magnetization control, the transmission output torque Tt also increases to its upper limit (the value obtained by multiplying pressure by the static friction coefficient) as the speed difference increases. If the variation in the transmission output torque Tt (flyout shock) exceeds the level of human perception, it may cause discomfort to the driver.

[0170] Furthermore, in μs matching control, if the transmission clutch 83 begins to slip upon the start of magnetization control, the transmission output torque Tt decreases to the value obtained by multiplying the pressing force by the dynamic friction coefficient as the friction coefficient switches. This state is maintained until the magnetization control ends and the transmission clutch 83 is re-engaged. If the variation in transmission output torque Tt during this period (pulling shock) exceeds the level of human perception, it may cause discomfort to the driver.

[0171] In any control method, if the difference between the static friction coefficient and the dynamic friction coefficient of the transmission clutch 83 is large, a torque shock caused by the difference in friction coefficient may be generated with the magnetization control, causing discomfort to the driver.

[0172] Another consideration was to suppress torque shocks by adjusting the pressing pressure of the transmission clutch 83 during engagement using hydraulic control. However, hydraulic control has low responsiveness and cannot respond instantaneously. With low-responsive hydraulic control, it is not easy to stably suppress torque shocks associated with irregular magnetization control.

[0173] Therefore, the control device is designed to suppress magnetic force changes of the drive motor, specifically unacceptable torque variations that may occur with magnetization control, through the control of the transmission clutch 83.

[0174] Specifically, similar to the previously proposed technology, torque control is performed while the vehicle 1 is in motion, along with the first clutch control. Furthermore, when magnetization control is performed while the vehicle 1 is in motion, the control switches from the first clutch control to the second clutch control before the magnetization control is executed. That is, by causing the transmission clutch 83 to slip, torque surges caused by magnetization are suppressed.

[0175] Furthermore, in this control device, a predetermined slip torque is added to the requested torque based on the dynamic friction coefficient and static friction coefficient of the transmission clutch 83, and a new requested torque (micro-increase requested torque) is set. Then, together with the change to control the second clutch (i.e., before performing magnetization control), based on this micro-increase requested torque, control to set the transmission clutch 83 from the engaged state to the micro-slip state (micro-slip control) is initiated.

[0176] That is, when the speed difference of the transmission clutch 83 increases sharply (when magnetization begins), instead of switching the transmission clutch 83 from the engaged state to the disengaged state, it is switched to a slightly slipping state (micro-slipping state) before that. As a result, the friction coefficient can be switched from the static friction coefficient to the dynamic friction coefficient in advance under the condition of small speed difference, thus suppressing the torque shock caused by the friction coefficient difference.

[0177] In the micro-slip state, the transmission clutch 83 is not fully engaged, and the friction coefficient only needs to switch from the static friction coefficient to the dynamic friction coefficient. By changing the control of the second clutch, the clutch engagement torque is consistent with the requested torque. Therefore, the slip torque added to the requested torque is only sufficient to generate the micro-slip state.

[0178] In the execution of micro-slip control, power control is preferably performed instead of torque control. Moreover, more preferably, after the magnetization control is performed, feedback control is performed based on the difference between the speed of the input side 83a and the speed of the output side 83b of the transmission clutch 83, and converges to the micro-slip state during the execution of power control.

[0179] In this way, the rotational speed can be adjusted in a balanced manner along with the torque output by the drive motor 3, quickly eliminating any spikes. Therefore, the drive motor 3 can be restored to its original state in a short time after magnetization.

[0180] <Power control and feedback control with micro-slider control>

[0181] In power control, torque control is performed so that the power output from drive wheel 4R, i.e., the multiplication of the torque T and speed R of drive wheel 4R, becomes the power value set as a predetermined target (target power value).

[0182] In other words, in power control, torque control is performed by setting the motor torque Tm corresponding to the target power value, rather than the requested torque Ta, as the target torque. If the target power value is constant, then if the motor speed Rm is as high as at the peak of a surge, the target torque decreases accordingly; if the surge weakens and the motor speed Rm decreases, then the target torque increases. Therefore, unlike torque control, power control can balance both speed and torque.

[0183] The target power value here is the value at which the transmission clutch 83 becomes slightly slippery. Therefore, during the execution of the slightly slippery control, the torque and speed of the drive motor 3 can be adjusted in a balanced manner, and the system can stably converge to the slightly slippery state.

[0184] Specifically, the target power value here is set to the value obtained by multiplying the slightly increased requested torque by the rotational speed. For example, the target power value can be set by multiplying the requested torque Ta by the actual rotational speed of the drive motor 3 by a specified slip ratio, such as 105%.

[0185] The target power value is obtained by multiplying the requested torque Ta by the actual speed and the specified slip ratio. Therefore, power control is an auxiliary control to torque control and is well compatible with torque control. Consequently, these controls can switch smoothly and easily between each other, resulting in excellent control stability.

[0186] After the magnetization control is implemented, the motor torque Tm decreases through power control, and the motor speed Rm also decreases. However, the motor speed Rm at this time passively changes according to the change in torque. Therefore, the motor speed Rm decreases slowly. Thus, it takes a relatively long time for the motor speed Rm to converge to the speed of the micro-slippery state (micro-slippery speed).

[0187] Therefore, after the magnetization control is executed, feedback control is performed based on the difference (speed difference) between the speed of the input side 83a and the speed of the output side 83b of the transmission clutch 83 used, and converges to a micro-slip state during the execution of power control.

[0188] If feedback control is initiated, the gain of torque control is adjusted based on the speed difference to quickly transition to a micro-slip state. This allows the transmission clutch 83 to rapidly converge back to its initial micro-slip state.

[0189] <Transition Control>

[0190] Furthermore, at the beginning and / or end of the micro-slip control, it is preferable to perform coordinated control using hydraulic control. Specifically, control (transition control) that adjusts the hydraulic pressure of the transmission clutch 83 is performed together with the torque adjustment so that the torque change (torque shock) caused by the change in the state of the transmission clutch 83 before and after the micro-slip control is canceled out.

[0191] For example, at the start of micro-slip control, the transmission clutch 83 changes from an engaged state to a micro-slip state. At the end of micro-slip control, the transmission clutch 83 changes from a micro-slip state back to an engaged state. With these state changes of the transmission clutch 83, a torque change is generated due to the difference in the friction coefficients of the transmission clutches 83.

[0192] Unlike magnetization control, where the output torque is irregular and difficult to determine in advance, the sliding torque added or subtracted in micro-slip control is a preset value. The torque change caused by the switching of the friction coefficient at the start or end of micro-slip control is determined based on this sliding torque, so even hydraulic control with poor responsiveness can be adjusted according to this torque change.

[0193] For example, by setting conditions for hydraulic control that can counteract torque changes associated with increases or decreases in slip torque through preliminary tests, the hydraulic pressure (pressing force) of the transmission clutch 83 can be adjusted accordingly. This also suppresses minor torque shocks caused by differences in the coefficient of friction resulting from micro-slip control. As a result, the magnetic force of the drive motor 3 can be changed with virtually no shock.

[0194] <Specific Control Example>

[0195] Figure 12 , Figure 13 , Figure 14 The figure shows a specific control example related to micro-sliding control. Figure 12 It is a timing diagram of the main parameters before and after magnetization control. Figure 13 and Figure 14 It is the control device that performs the operation with Figure 12 The corresponding control flowchart.

[0196] exist Figure 12 The image above is a timing diagram related to torque. The solid line represents the transmission input torque (motor torque Tm), and the dashed line represents the transmission output torque.

[0197] The middle diagram is a timing diagram related to the hydraulic pressure of the transmission 8 (the pressing force of the transmission clutch 83). The bottom diagram is a timing diagram related to the speed difference. It shows the speed difference between the input side 83a and the output side 83b of the transmission clutch 83 in use.

[0198] like Figure 13 As shown, MCU21 determines whether to execute magnetization control (step S30). Furthermore, if it is determined that magnetization control should be executed, TCU22 switches from first clutch control to second clutch control (step S31). As a result, the clutch engagement torque Tt becomes consistent with the requested torque Ta.

[0199] In addition, the transition control executed after TCU22 begins the hydraulic adjustment (step S32). Specifically, the hydraulic pressure supplied to the transmission 8 is reduced to a pre-set set hydraulic pressure Pt.

[0200] Then, in the state where the hydraulic pressure changes to the set hydraulic pressure Pt ( Figure 12 In step S0), MCU21 interrupts torque control and begins torque adjustment for transition control (step S33). That is, by applying slip torque, the requested torque Ta is changed to a slightly increased requested torque Ta', so that the transmission clutch 83 used changes from the engaged state to a slightly slipped state.

[0201] As a result, the transmission clutch 83 begins to slip slightly, and the speed difference increases. Figure 12 (t0~t1 in the text). Because the friction coefficient switches from the static friction coefficient to the dynamic friction coefficient, the output torque of the transmission decreases accordingly. Furthermore, this control example illustrates the case where the torque control performs the aforementioned μs matching control.

[0202] TCU22, in conjunction with the reduction in the output torque of the transmission, causes the hydraulic pressure to rise. Figure 12The torque distribution (t0 to t2) is adjusted to offset the reduction in output torque of the transmission. This suppresses torque surges caused by differences in friction coefficients, controlling the torque variation to a level imperceptible to humans. Therefore, the transmission clutch 83 can be switched from the engaged state to the slightly slipping state without causing discomfort to the driver.

[0203] If the speed difference reaches the speed Rs (micro-slip speed) corresponding to the micro-slip state ( Figure 12 If t1 is reached, then MCU21 begins power control targeting the micro-slip state (step S34). Consequently, the transmission clutch 83 converges to the micro-slip state and maintains this state. The transmission input torque stabilizes at the slightly increased requested torque Ta', and the speed difference stabilizes at the micro-slip speed Rs. Figure 12 (After t2 in the middle). The hydraulic pressure also stabilizes at the specified hydraulic pressure.

[0204] If the transmission clutch 83 becomes slightly slippery, the MCU21 starts magnetization control (step S35). Figure 12 The period from t3 to t4 corresponds to magnetization control (including learning control). During this period, as mentioned above, a high motor torque Tm is output from the drive motor 33. Correspondingly, the motor speed Rm increases, and the speed difference also increases (surge phenomenon).

[0205] To address this, the clutch engagement torque Tt is matched with the requested torque Ta through second clutch control. Therefore, even with a high motor torque Tm output via magnetization control, the transmission output torque, approximately the same as the requested torque Ta, is output downstream of the transmission clutch 83. This effectively suppresses torque surges caused by magnetization.

[0206] If the magnetization control ends (Yes in step S36), the transmission input torque decreases. Power control is also performed during this period. In power control, as described above, torque control is performed using a target torque corresponding to the target power value. Therefore, with the end of the magnetization control, the increased transmission input torque decreases, and the speed difference also decreases.

[0207] However, the speed difference decreases slowly at this point. Therefore, it takes a relatively long time to converge to the micro-slip speed Rs. Therefore, the MCU21 cooperates with the TCU22 (transmission clutch control unit 22b) to initiate feedback control during the execution of power control.

[0208] That is, such as Figure 14 As shown, if the speed difference is lower than the reference value Rf ("Yes" in step S37), feedback control begins (step S38). The reference value Rf is set in TCU22 according to the specifications of the transmission 8.

[0209] TCU22 compares the measured or inferred speed difference based on the detection value of transmission sensor 55 with the reference value Rf. Furthermore, if it is determined that the speed difference is lower than the reference value Rf ( Figure 12 In step t5), feedback control is initiated on the speed of the transmission clutch 83 to converge to a micro-slip state, that is, to make the speed difference a micro-slip speed Rs. Through the execution of feedback control, the transmission clutch 83 can be quickly restored to the micro-slip state.

[0210] Therefore, if the speed difference reaches the micro-slip speed Rs ("Yes" in step S39), that is, if the transmission clutch 83 returns to the micro-slip state, then power control and feedback control end, and transition control begins (step S40). Figure 12 (t6 in the middle).

[0211] That is, MCU21 changes the slightly increased requested torque Ta' to the requested torque Ta by removing the slip torque, so that the transmission clutch 83 changes from the slightly slipped state to the engaged state.

[0212] Along with this, the speed difference decreases ( Figure 12 (t6~t7 in the text). If the transmission clutch 83 is engaged, the coefficient of friction switches from the dynamic friction coefficient to the static friction coefficient, and therefore, the transmission output torque increases accordingly.

[0213] TCU22 reduces hydraulic pressure in response to the increase in transmission output torque, thus offsetting the increase. This suppresses torque surges caused by differences in friction coefficients, keeping torque changes to a level imperceptible to the human. Therefore, the transmission clutch 83 can be switched from a slightly slipping state to a engaged state without causing discomfort to the driver.

[0214] Through this series of processes, the surge was eliminated, and the motor torque Tm and motor speed Rm returned to their original states. The transmission clutch 83 also returned to the engaged state. Figure 12 (t7 in the text). Therefore, MCU21 restarts torque control (step S41).

[0215] TCU22 switches from second clutch control to first clutch control (step S42). As a result, the clutch engagement torque Tt rises to its normal value. Figure 12 (After t7 in the middle). In addition, TCU22 also increases the hydraulic pressure supplied to the transmission 8 to its normal value. As a result, the drive motor 3 and the transmission 8 return to their state before the magnetization control.

[0216] Thus, according to the control device employing the disclosed technology, even when magnetization control is performed to generate a motor torque Tm higher than the requested torque during the driving of the vehicle 1, the torque surge caused by magnetization can be suppressed by the second clutch control. Furthermore, since the surge in drive motor 33 caused by the slippage of the transmission clutch 83 can be quickly eliminated by power control and feedback control, a smooth return to an appropriate control state can be achieved.

[0217] Furthermore, the torque shock caused by the difference in friction coefficients of the transmission clutch 83 can be suppressed through micro-slip control. Therefore, even if there is a large difference between the dynamic and static friction coefficients of the transmission clutch 83, there is no need to worry about causing discomfort to the driver.

[0218] This control device can suppress torque fluctuations caused by changes in the magnetic force of the drive motor 3 without affecting the performance of the transmission clutch 83. This expands the application range of the transmission clutch 83, thus offering excellent convenience.

[0219] Furthermore, the disclosed technology is not limited to the embodiments described above, but also includes various other structures. For example, there are various structures for the drive motor 3, the transmission 8, etc. The same applies to the automobile 1. Therefore, these structures can be selected according to specifications, and the disclosed technology can be applied according to those specifications.

Claims

1. A control device for an electric vehicle capable of operating by electricity, the electric vehicle comprising a drive motor having rotor poles composed of a variable-force magnet capable of changing magnetic force, and a clutch disposed between the drive motor and a drive wheel. The control device is characterized in that... When the electric vehicle is in motion, torque control is performed to control the motor torque output by the drive motor to match the requested torque to be output to the drive wheels, and simultaneously, a first clutch control is performed to control the engagement torque of the clutch to be higher than the requested torque. When the electric vehicle is in motion, and magnetization control is executed to change the magnetic force of the variable magnet in the magnetization direction, before executing the magnetization control, the first clutch control is changed to a second clutch control that makes the engagement torque consistent with the requested torque. Furthermore, a micro-slip control is initiated to set the clutch from the engagement state to a micro-slip state by adding a pre-set, predetermined slip torque to the requested torque based on the clutch's dynamic and static friction coefficients. At the end of the micro-slip control, a transition control is performed to adjust the hydraulic pressure of the clutch so that the torque change caused by the clutch changing from the micro-slip state to the engaged state is offset.

2. The control device according to claim 1, characterized in that, When the micro-slip control begins, a transition control is performed to adjust the hydraulic pressure of the clutch so as to offset the torque change that occurs as the clutch changes from the engaged state to the micro-slip state.

3. The control device according to claim 1 or 2, characterized in that, During the execution of the micro-slip control, instead of the torque control, power control is performed to control the motor torque so that the power output from the drive wheel matches a predetermined target power value.

4. The control device according to claim 3, characterized in that, After the magnetization control is executed, feedback control is performed based on the difference between the speed on the input side and the speed on the output side of the clutch, and the power control converges to the micro-slip state during the execution of the power control.

Images