JP2022048448A - vehicle - Google Patents

Abstract

To provide a vehicle having a resolver for detecting a rotation angle of a rotor of a motor generator which more surely protects a storage battery.SOLUTION: A vehicle 1 includes: a resolver 66 for detecting a rotation angle of a motor generator 50; and an ECU 70 having a plurality of control modes for feedback controlling an inverter 40 using a detection value of the resolver 66. The plurality of control modes include a rectangular wave control mode of performing torque feedback control, and a PWM control mode of performing current feedback control. When charging of a battery 10 is inhibited and the rectangular wave control mode is selected, the ECU 70 switches a control mode of the inverter 40 from the rectangular wave control mode to the PWM control mode when a temperature of the battery 10 increases higher than a predetermined amount.SELECTED DRAWING: Figure 8

Description

The present disclosure relates to a vehicle, and more specifically to a vehicle provided with a resolver that detects the angle of rotation of the motor generator.

Vehicles such as hybrid vehicles or electric vehicles are equipped with motor generators for driving. The motor generator is provided with a resolver (rotation angle sensor). The angle of rotation (position information of the rotor of the motor generator) detected by the resolver is used to generate torque commands and speed commands for the vehicle.

The output from the resolver may include an offset due to an assembly error or the like in the manufacturing process. Therefore, a technique for measuring or correcting the offset of the resolver has been proposed. For example, Japanese Patent Application Laid-Open No. 2017-108599 (Patent Document 1) discloses a method for measuring an offset of a resolver. In this method, the offset of the resolver is frequently measured by actively controlling the zero current of the motor while the vehicle is running.

JP-A-2017-108599

The motor generator regenerates power when the vehicle is traveling downhill. The vehicle is further equipped with an inverter that converts the power generated by the motor generator into DC power, and a storage battery that is charged by the DC power from the inverter.

When the vehicle is evacuated, control to reduce the generated power generated by the motor generator to zero (that is, control to prohibit regenerative power generation) may be executed. If the speed of the vehicle becomes faster than a predetermined speed during the execution of this control, the motor generator is controlled according to the square wave control mode. The square wave control mode is a mode in which torque feedback control is performed so that a phase-controlled square wave voltage is applied to the motor generator.

When the square wave control mode is selected, the influence of the offset of the resolver is large, and even if the regenerative power generation of the motor generator is prohibited, the power generation by the motor generator can be performed (details will be described later). Then, the generated power is charged to the storage battery, and the storage battery may be damaged (for example, the storage battery may be overcharged).

The present disclosure has been made to solve the above problems, and an object of the present disclosure is to more reliably protect a storage battery in a vehicle equipped with a resolver that detects the rotation angle of a motor generator.

Vehicles according to certain aspects of the present disclosure include a motor generator for driving, a resolver that detects the rotation angle of the motor generator, an inverter that drives the motor generator, a storage battery that is charged through the inverter by the generated power of the motor generator, and a resolver. It is provided with a control device having a plurality of control modes for feedback-controlling the inverter using the detected value of. Multiple control modes include a square wave control mode in which torque feedback control is performed so that a phase-controlled square wave voltage is applied to the motor generator, and current feedback so that a pulse width modulated voltage is applied to the motor generator. Includes a pulse width modulation control mode for control.

When charging of the storage battery is prohibited (accordingly, regenerative power generation of the motor generator) and the square wave control mode is selected, the control device controls the inverter when the temperature of the storage battery rises above a predetermined amount. To switch from the square wave control mode to the pulse width modulation control mode.

Comparing the square wave control mode and the pulse width modulation control mode, the pulse width modulation control mode in which the current feedback control is performed can reduce the current error more reliably than the square wave control mode in which the torque feedback control is performed. High resistance to resolver offset (details below). Therefore, by switching the control mode to the pulse width modulation control mode, the influence of the offset of the resolver can be reduced, and thereby the control for prohibiting the regenerative power generation of the motor generator can be accurately executed. Therefore, according to the above configuration, the storage battery can be protected more reliably.

According to the present disclosure, the storage battery can be more reliably protected in a vehicle provided with a resolver that detects the rotation angle of the motor generator.

It is a figure which shows schematic about the whole structure of the vehicle which concerns on this embodiment. It is a figure for demonstrating the outline of the control mode of an inverter. It is a figure for demonstrating the use area of the control mode of an inverter. It is a functional block diagram which shows the functional composition of the ECU regarding the control of a motor generator. It is a functional block diagram which shows the structure of a PWM control unit. It is a functional block diagram which shows the structure of the rectangular wave control part. It is a figure for demonstrating the offset of a resolver. It is a flowchart which shows the control of the motor generator in this embodiment.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals, and the description thereof will not be repeated.

[Embodiment]
<Vehicle configuration>
FIG. 1 is a diagram schematically showing an overall configuration of a vehicle according to the present embodiment. With reference to FIG. 1, the vehicle 1 is an electric vehicle (EV). The vehicle 1 includes a battery 10, a system main relay (SMR) 20, a positive electrode line PL1, a negative voltage line NL, a capacitor C1, a converter 30, a positive electrode line PL2, a capacitor C0, and an inverter 40. , Motor Generator (MG) 50, battery voltage sensor 61, battery current sensor 62, battery temperature sensor 63, system voltage sensor 64, motor current sensor 65, resolver 66, and vehicle speed sensor 67. And an ECU (Electronic Control Unit) 70.

The battery 10 is an assembled battery including a plurality of cells. Each cell is a secondary battery such as a lithium ion battery or a nickel metal hydride battery. The battery 10 supplies electric power for generating the driving force of the vehicle 1. Further, the battery 10 stores the electric power generated by the motor generator 50.

The lithium ion battery is a secondary battery using lithium as a charge carrier, and may include an all-solid-state battery using a solid electrolyte as well as a general lithium ion battery having a liquid electrolyte. A capacitor such as an electric double layer capacitor may be adopted instead of the battery 10.

The battery voltage sensor 61 detects the voltage Vb of the battery 10. The battery current sensor 62 detects the current Ib input / output to / from the battery 10. The battery temperature sensor 63 detects the temperature Tb of the battery 10. Each sensor outputs the detected value to the ECU 70.

The SMR 20 is electrically connected between the battery 10 and the converter 30. The SMR 20 is closed according to a command from the ECU 70. By closing the SMR 20, power can be transmitted between the battery 10 and the converter 30.

The positive electrode line PL1 electrically connects the positive electrode end of the battery 10 and the converter 30. The negative electrode wire NL electrically connects the negative electrode end of the battery 10 and the converter 30.

The capacitor C1 is connected between the positive electrode line PL1 and the negative electrode line NL.

The converter 30 includes a reactor L1, switching elements Q1 and Q2, and diodes D1 and D2. The switching elements Q1 and Q2 are connected in series between the positive electrode line PL2 and the negative electrode line NL. The switching elements Q1 and Q2 each perform a switching operation (on / off operation) according to the switching commands S1 and S2 from the ECU 70. As the switching elements Q1 and Q2 and the switching elements Q3 to Q8 described later, an IGBT (Insulated Gate Bipolar Transistor), a power MOS (Metal Oxide Semiconductor) transistor, a power bipolar transistor and the like can be used. The diodes D1 and D2 are connected to the switching elements Q1 and Q2 in antiparallel, respectively. The reactor L1 is connected between the connection node of the switching elements Q1 and Q2 and the positive electrode line PL1.

The converter 30 is basically controlled so that the switching elements Q1 and Q2 perform complementary and alternating switching operations within each switching cycle. The converter 30 boosts the voltage Vb of the battery 10 and outputs the boosted voltage (system voltage) VH to the inverter 40. This boosting operation is realized by supplying the electromagnetic energy stored in the reactor L1 during the ON period of the switching element Q2 to the positive electrode line PL2 via the switching element Q1 and the diode D1. The voltage conversion ratio (ratio of VH and Vb) in the boosting operation is controlled by the on-period ratio (duty ratio) of the switching elements Q1 and Q2 with respect to the switching cycle. If the switching element Q1 is fixed on and the switching element Q2 is fixed off, VH = Vb (voltage conversion ratio = 1.0) can be set.

The positive electrode line PL2 electrically connects the high potential end of the converter 30 and the high potential end of the inverter 40. The negative electrode wire NL electrically connects the low potential end of the converter 30 and the low potential end of the inverter 40.

The capacitor C0 is connected between the positive electrode line PL2 and the negative electrode line NL. The capacitor C0 smoothes the DC voltage from the converter 30 and supplies the smoothed DC voltage to the inverter 40.

The system voltage sensor 64 detects the voltage across the capacitor C0 (hereinafter, also referred to as “system voltage”) VH, and outputs the detected value to the ECU 70.

The inverter 40 includes a U-phase arm 41, a V-phase arm 42, and a W-phase arm 43. The U-phase arm 41, the V-phase arm 42, and the W-phase arm 43 are connected in parallel between the positive electrode line PL2 and the negative electrode line NL. Each phase arm includes a switching element connected in series between the positive electrode line PL2 and the negative electrode line NL. The U-phase arm 41 includes switching elements Q3 and Q4, the V-phase arm 42 includes switching elements Q5 and Q6, and the W-phase arm 43 includes switching elements Q7 and Q8. The switching elements Q3 to Q8 each perform a switching operation according to the switching commands S3 to S8 from the ECU 70. Diodes D3 to D8 are connected to the switching elements Q3 to Q8 in antiparallel.

The inverter 40 converts the DC power from the converter 30 into AC power by switching the switching elements Q3 to Q8, and supplies the converted AC power to the motor generator 50. When the torque command value of the motor generator 50 is positive or 0 (Trqcom ≧ 0), the inverter 40 drives the motor generator 50 so that the motor generator 50 outputs a positive torque by the AC power from the inverter 40. do. At the time of regenerative braking of the vehicle 1, the torque command value of the motor generator 50 is set to a negative value (Trqcom <0). In this case, the inverter 40 converts the AC power generated by the motor generator 50 into DC power, and supplies the DC power to the converter 30.

The motor generator 50 is an AC rotary electric machine. The output torque of the motor generator 50 is transmitted to the drive wheels (none of which are shown) through the power transmission gear to drive the vehicle 1. Further, the motor generator 50 generates electricity by the rotational force of the drive wheels during the regenerative braking of the vehicle 1 (regenerative power generation).

The motor generator 50 is typically a three-phase permanent magnet type synchronous motor, and is configured such that one end of three coils of U-phase, V-phase, and W-phase is commonly connected to a neutral point. The other ends of the U-phase, V-phase, and W-phase coils are connected to the intermediate points of the switching elements of the U-phase arm 41, the V-phase arm 42, and the W-phase arm 43, respectively.

The motor current sensor 65 detects a current flowing through the motor generator 50 (hereinafter, also referred to as “motor current”), and outputs the detected value to the ECU 70. More specifically, since the sum of the instantaneous values of the three-phase motor currents (U-phase current iu, V-phase current iv, W-phase current iw) is zero, the motor current sensor 65 has a motor current for two phases (U-phase current iv, W-phase current iv). In this example, the V-phase current iv and the W-phase current if) are arranged to be detected.

The resolver (rotation angle sensor) 66 detects the rotation angle θ of the rotor of the motor generator 50 and outputs the detected value to the ECU 70. The ECU 70 can calculate the rotation speed and the angular velocity ω of the motor generator 50 based on the rotation angle θ.

The vehicle speed sensor 67 detects the speed of the vehicle 1 (hereinafter, also referred to as “vehicle speed V”), and outputs the detected value to the ECU 80.

The ECU 70 includes a processor such as a CPU (Central Processing Unit), a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and an I / O port for inputting / outputting various signals (both). Not shown). The ECU 70 executes various controls such as the running state of the vehicle 1 and the charging / discharging of the battery 10 based on the signal received from each sensor, the program stored in the memory, the map, and the like.

Note that these controls are not limited to software processing, but it is also possible to construct and process dedicated hardware (electronic circuits). Further, the ECU 70 may be divided into a plurality of ECUs (battery ECU, MG ECU, etc.) for each function.

A typical function of the ECU 70 in this embodiment is feedback control of the inverter 40. The ECU 70 operates the inverter 40 based on the torque command value Trqcom, the voltage Vb of the battery 10, the current Ib and the temperature Tb, the system voltage VH, the motor current (V-phase current iv and the W-phase current if), the rotation angle θ, and the like. To control. As a result, the motor generator 50 is driven so as to generate the torque (zero or positive torque) specified by the torque command value Trqcom.

<Inverter control mode>
The ECU 70 is configured to drive the motor generator 50 by controlling the inverter 40 according to various control modes described below. These control modes are selectively (alternatively) executed.

FIG. 2 is a diagram for explaining an outline of the control mode of the inverter 40. With reference to FIG. 2, the ECU 70 has a pulse width modulation (PWM) control mode and a square wave control mode. The PWM control mode includes a sinusoidal PWM control mode and an overmodulation PWM control mode.

In the sinusoidal PWM control, the upper and lower arms of each phase of the inverter 40 are switched and controlled according to the pulse width modulated signal generated based on the magnitude comparison result between the sinusoidal voltage command and the carrier wave. As a result, for the set of the high level period (upper arm on period) and the low level period (lower arm on period), the duty ratio of the upper and lower arms is changed so that the fundamental wave component becomes a sine wave within a certain period. Be controlled.

Hereinafter, the voltage applied to the motor generator 50 (line voltage) is also simply referred to as “motor voltage”. The motor voltage includes a d-axis component Vd and a q-axis component Vq. Further, the ratio of the fundamental wave component (effective value) of the output voltage (= motor voltage) from the inverter 40 to the input voltage (= system voltage VH) to the inverter 40 is also referred to as “modulation rate”. The modulation factor can be defined by the following equation (1).
Modulation rate = √ (Vd ² + Vq ² ) / VH ・ ・ ・ (1)

In the sinusoidal PWM control, the amplitude of the sinusoidal voltage command is limited to the range below the carrier wave amplitude. Therefore, the modulation factor can be increased only to about 0.61 at the maximum.

The overmodulated PWM control is the same PWM control as the sinusoidal PWM control, but differs from the sinusoidal PWM control in that the amplitude of the voltage command is in a range larger than the carrier wave amplitude. In overmodulation PWM control, the fundamental wave component can be increased by distorting the voltage command from the original sinusoidal waveform (amplitude correction), thereby changing the modulation factor to the maximum modulation factor in sinusoidal PWM control (≈0). It can be increased from .61) to about 0.78.

In the square wave control, a phase-controlled square wave voltage is applied to the motor generator 50. More specifically, within a certain period, a voltage corresponding to one pulse of a square wave is applied to the motor generator 50 so that the ratio of the high level period to the low level period becomes 1: 1. As a result, the modulation factor can be increased to about 0.78 in the rectangular wave control.

FIG. 3 is a diagram for explaining a usage area of the control mode of the inverter 40. In FIG. 3, the horizontal axis represents the rotation speed of the motor generator 50. The vertical axis represents the output torque of the motor generator 50. In the vehicle 1, the rotation speed of the motor generator 50 depends on the vehicle speed V.

With reference to FIG. 3, the ECU 70 selects which control mode to use based on the modulation factor. Specifically, the ECU 70 selects the sinusoidal PWM control mode in the low rotation speed region where the motor voltage is low and the modulation factor is low. The ECU 70 selects the overmodulation PWM control mode in the medium rotation speed range in which the modulation factor increases as the motor voltage increases. The ECU 70 selects the square wave control mode in the high rotation speed range where the modulation factor is further higher.

<Switching control mode>
FIG. 4 is a functional block diagram showing a functional configuration of the ECU 70 regarding the control mode of the inverter 40. With reference to FIG. 4, the ECU 70 includes a PWM control unit 71, a square wave control unit 72, and a control mode switching unit 73.

The PWM control unit 71 receives the torque command value Trqcom, the motor currents iv and iwa detected by the motor current sensor 65, and the rotation angle θ detected by the resolver 66. Based on these detected values, the PWM control unit 71 generates voltage command values (d-axis voltage command value Vd # and q-axis voltage command value Vq #) applied to the inverter 40 by current feedback control. Then, the PWM control unit 71 generates switching commands S3 to S8 for driving the inverter 40 based on the generated voltage command values Vd # and Vq #, and outputs them to the control mode switching unit 73. The configuration of the PWM control unit 71 will be described in more detail with reference to FIG.

Similar to the PWM control unit 71, the rectangular wave control unit 72 receives the torque command value Trqcom, the motor currents iv and iwa, and the rotation angle θ. The square wave control unit 72 sets the phase (voltage phase φv) of the square wave voltage applied to the inverter 40 by torque feedback control based on these detected values. Then, the rectangular wave control unit 72 generates switching commands S3 to S8 for driving the inverter 40 based on the set phase, and outputs the switching commands to the control mode switching unit 73. The configuration of the rectangular wave control unit 72 will be described in more detail with reference to FIG.

The control mode switching unit 73 receives voltage command values Vd # and Vq # from the PWM control unit 71, and receives a system voltage VH from the system voltage sensor 64. The control mode switching unit 73 switches between PWM control and square wave control based on the modulation factor calculated from the voltage command values Vd # and Vq # and the system voltage VH. Specifically, when the modulation factor rises to the first predetermined value M1, the control mode switching unit 73 switches the control mode from the PWM control mode to the rectangular wave control mode. On the other hand, when the modulation factor drops to the second predetermined value M2 (however, M2 <M1), the control mode switching unit 73 switches the control mode from the rectangular wave control mode to the PWM control mode. The reason why M2 <M1 is set is to prevent chattering.

<PWM control>
FIG. 5 is a functional block diagram showing the configuration of the PWM control unit 71. With reference to FIG. 5, the PWM control unit 71 includes a current command generation unit 711, a coordinate conversion unit 712, a proportional integration (PI: Proportional Integral) calculation unit 713, 714, a coordinate conversion unit 715, and a PWM modulation unit. 716 and included.

The current command generator 711 uses a prepared map (or table) showing the relationship between the torque and the d-axis current and the q-axis current, and the d-axis current corresponding to the torque command value Trqcom of the motor generator 50. The command value Idcom and the q-axis current command value Iqcom are generated. The d-axis current command value Idcom is output to the PI calculation unit 713, and the q-axis current command value Iqcom is output to the PI calculation unit 714.

The coordinate conversion unit 712 converts the V-phase current iv and the W-phase current iv detected by the motor current sensor 65 into the d-axis current Id and the coordinate conversion (uvw3 phase → dq2 phase) using the rotation angle θ of the motor generator 50. Convert to q-axis current Iq. This coordinate transformation is performed for the purpose of simplifying control. The d-axis current Id is output to the PI calculation unit 713, and the q-axis current Iq is output to the PI calculation unit 714.

The PI calculation unit 713 calculates the d-axis voltage command value Vd # by performing a PI calculation according to the following equation (2) for the deviation ΔId (ΔId = Idcom-Id) of the d-axis current Id with respect to the d-axis current command value Idcom. do. The d-axis voltage command value Vd # is output to the coordinate conversion unit 715.
Vd # = Kdp × ΔId + Kdi × ΣΔId ・ ・ ・ (2)

The PI calculation unit 714 calculates the q-axis voltage command value Vq # by performing a PI calculation according to the following equation (3) for the deviation ΔIq (ΔIq = Iqcom-Iq) of the q-axis current with respect to the q-axis current command value Iqcom. calculate. The q-axis voltage command value Vq # is output to the coordinate conversion unit 715.
Vq # = Kdq × ΔIq + Kqi × ΣΔIq ・ ・ ・ (3)

In the equations (2) and (3), Kdp and Kdq are proportional gains, and Kdi and Kqi are integral gains.

The coordinate conversion unit 715 converts the d-axis voltage command value Vd # and the q-axis voltage command value Vq # into U-phase, V-phase, and W by coordinate conversion (dq2 phase → uvw3 phase) using the rotation angle θ of the motor generator 50. Each phase is converted into voltage command values Vu, Vv, Vw. Each phase voltage command value Vu, Vv, Vw is output to the PWM modulation unit 716.

The PWM modulation unit 716 generates switching commands S3 to S8 (PWM signals) based on the comparison between each phase voltage command value Vu, Vv, Vw and the carrier wave. The carrier wave is typically a triangular wave or a sawtooth wave.

<Square wave control>
FIG. 6 is a functional block diagram showing the configuration of the rectangular wave control unit 72. With reference to FIG. 6, the square wave control unit 72 includes a coordinate conversion unit 721, a torque estimation unit 722, a PI calculation unit 723, and a switching command calculation unit 724.

The coordinate conversion unit 721 converts the V-phase current iv and the W-phase current iv detected by the motor current sensor 65 into the d-axis current Id and the coordinate conversion (uvw3 phase → dq2 phase) using the rotation angle θ of the motor generator 50. Convert to q-axis current Iq. The d-axis current Id and the q-axis current Iq are output to the torque estimation unit 722.

The torque estimation unit 722 uses a pre-prepared map (or table) showing the d-axis current and the relationship between the q-axis current and the torque, and the torque of the motor generator 50 from the d-axis current Id and the q-axis current Iq. The estimated value Trq is calculated. The torque estimation value Trq is output to the PI calculation unit 723.

The PI calculation unit 723 calculates the voltage phase φv of the rectangular wave voltage by performing the PI calculation according to the following equation (4) for the deviation ΔTrq (ΔTrq = Trqcom−Trq) of the torque estimation value Trq with respect to the torque command value Trqcom. The voltage phase φv is output to the switching command calculation unit 724. Note that Kp and Ki are proportional gain and integral gain, respectively, and both are positive values.
φv = Kp × ΔTrq + Ki × ΣΔTrq ・ ・ ・ (4)

In this torque feedback control, when positive torque is generated (Trqcom> 0), the voltage phase φv is advanced (φv> 0) when the torque is insufficient (ΔTrq> 0), while when the torque is excessive (ΔTrq <0). Delays the voltage phase φv (φv <0). When a negative torque is generated (Trqcom <0), the voltage phase φv is delayed when the torque is insufficient, while the voltage phase φv is advanced when the torque is excessive.

The switching command calculation unit 724 generates each phase voltage command value (square wave pulse) Vu, Vv, Vw according to the voltage phase φv, and the switching command S3 to S8 based on the generated phase voltage command values Vu, Vv, Vw. To generate. Then, the inverter 40 performs a switching operation according to the switching commands S3 to S8, so that a square wave pulse according to the voltage phase φv is applied as each phase voltage of the motor generator 50.

<Resolver offset>
FIG. 7 is a diagram for explaining the offset of the resolver 66. With reference to FIG. 7, the output from the resolver 66 may include an error due to factors such as an assembly error in the manufacturing process of the vehicle 1 and the position uncertainty of the internal coil of the resolver 66. This error is called "resolver offset" and is indicated by Δθ in the figure.

It is also conceivable to measure the resolver offset Δθ and correct (in other words, learn) the resolver offset Δθ. For example, while the vehicle 1 is traveling, a current can be passed only on the q-axis at the time of torque command, and the deviation between the q-axis current command value Iqcom and the q-axis current Iq can be measured. However, the detection values of the motor current sensor 65 (V-phase current iv and W-phase current iw) are also used for the coordinate conversion of the feedback control, and the detection values of the motor current sensor 65 may also include an error. Therefore, even if the resolver offset Δθ is learned, it is difficult to completely remove the influence of the resolver offset Δθ from the feedback control.

For example, when the battery current sensor 62 provided in the battery 10 fails, the vehicle 1 shifts to the evacuation run. When the vehicle 1 is an electric vehicle as in the present embodiment, since the vehicle 1 does not have an engine as a power source, evacuation running is realized by using the battery 10 and the motor generator 50.

In order to protect the battery 10 when the vehicle 1 is retracted, the discharge power from the battery 10 (discharge power control upper limit value Wout) is suppressed as compared with the normal travel (when the retracted travel is not executed), and the discharge power is suppressed. The charging power to the battery 10 (the control upper limit value Win of the charging power) is suppressed. In particular, regarding charging, charging of the battery 10 is prohibited (Win = 0 is set) in order to prevent overcharging of the battery 10. As a result, regenerative power generation of the motor generator 50 is prohibited.

If the modulation factor exceeds the first predetermined value M1 such that the vehicle speed V becomes faster than the threshold speed during the evacuation of the vehicle 1 during the evacuation of the vehicle 1, the ECU 70 selects the rectangular wave control mode (the rectangular wave control mode). See Figure 3). When there is a resolver offset Δθ of a size that cannot be ignored (especially when the output of the resolver 66 is negatively offset), in the square wave control mode, even if Win = 0 is set, the power generated by the motor generator 50 is zero. Even if it is attempted to control the power generation, the motor generator 50 may intermittently generate regenerative power generation. Then, the generated power may be charged to the battery 10 and the battery 10 may be overcharged, resulting in damage to the battery 10.

In the present embodiment, the temperature Tb of the battery 10 is monitored during the evacuation running of the vehicle 1. When the temperature Tb of the battery 10 rises above a predetermined amount (ΔTb> reference amount REF), the generated power of the motor generator 50 is charged to the battery 10 even though charging of the battery 10 is prohibited. The battery 10 may have generated heat. This is considered to be due to the influence of the resolver offset Δθ. Therefore, the ECU 70 switches the control mode of the inverter 40 from the square wave control mode to the PWM control mode (sine wave PWM control mode or overmodulation PWM control mode).

As described with reference to FIG. 5, the PWM control mode is a mode for performing current feedback control. In the PWM control mode, the d-axis current Id (estimated value) is commanded by comparing the d-axis current Id fed back from the coordinate conversion unit 712 to the PI calculation unit 713 with the d-axis current command value Idcom. Close to the value Idcom. The same applies to the q-axis current Iq. The estimated values of the d-axis current Id and the q-axis current Iq are calculated using the detected values of the rotation angle θ from the resolver 66 (and the detected values of the currents iv and iwa from the motor current sensor 65). If there is an error between the command value (Iqcom, Iqcom) that prevents the charging current from flowing in the battery 10 and the estimated value, the d-axis current Id and the q-axis current are in the direction of reducing the current error. Iq is adjusted. Therefore, in the PWM control mode, it can be said that the charging current to the battery 10 does not become excessively large even if the resolver offset Δθ is present.

On the other hand, the rectangular wave control mode is a mode in which torque feedback control is performed (see FIG. 6). In the square wave control mode, the torque estimation value Trq is fed back from the torque estimation unit 722 to the PI calculation unit 723. Then, by comparing the torque estimated value Trq and the torque command value Trqcom, the torque estimated value Trq is brought closer to the torque command value Trqcom. When the resolver offset Δθ is large and there is an error in the d-axis current Id and the q-axis current Iq calculated using the rotation angle θ from the resolver 66, the torque feedback control acts in the direction of reducing the current error. Is not always the case. Although the error between the torque estimate and the command value is reduced, the current error can be increased. Therefore, it cannot be denied that the charging current to the battery 10 may increase as a result of the rectangular wave control mode.

As described above, when the PWM control mode and the rectangular wave control mode are compared, the PWM control mode in which the current feedback control is performed can more reliably reduce the current error than the rectangular wave control mode. Therefore, it can be expressed that the PWM control mode has higher resistance to the resolver offset Δθ.

In the present embodiment, when the temperature Tb of the battery 10 rises even though the charging of the battery 10 (regenerative power generation of the motor generator 50) is prohibited during the retracted running of the vehicle 1, the PWM control mode Select. In the PWM control mode, the influence of the resolver offset Δθ can be reduced, so that the prohibition of regenerative power generation of the motor generator 50 can be accurately controlled. This makes it possible to avoid overcharging the battery 10 and more reliably protect the battery 10.

<Control flow>
FIG. 8 is a flowchart showing the control of the motor generator 50 in the present embodiment. This flowchart is called (not shown) from the main routine and executed when a predetermined condition is satisfied or every calculation cycle. Each step is realized by software processing by the ECU 70, but may be realized by hardware (electric circuit) manufactured in the ECU 70. Hereinafter, the step is abbreviated as "ST".

With reference to FIG. 8, in ST1, the ECU 70 determines whether or not a diagnosis (automatic failure diagnosis) indicating an abnormality such as a failure of the battery current sensor 62 has occurred. The type of diagnostic is not limited to this as long as it requires Win = 0, and may be, for example, a failure of the battery voltage sensor 61.

When no diagnosis has occurred (NO in ST1), the ECU 70 returns the process to the main routine without executing the subsequent process. When the diagnosis is generated (YES in ST1), the ECU 70 evacuates the vehicle 1 (ST2). At this time, the ECU 70 suppresses the discharge of the battery 10 (sets Wout small) as compared with the normal running of the vehicle 1, and prohibits the charging of the battery 10 (sets Win = 0).

In ST3, the ECU 70 determines whether or not the modulation factor exceeds the first predetermined value M1 because the vehicle speed V is faster than the threshold speed or the like. When the modulation factor is higher than the first predetermined value M1 (YES in ST3), the ECU 70 selects the rectangular wave control mode as the control mode of the inverter 40 (ST4).

When the modulation factor does not exceed the first predetermined value M1 (NO in ST3), the ECU 70 determines whether the modulation factor is lower than the second predetermined value M2 (<M1) (ST11). When the modulation factor is lower than the second predetermined value M2 (YES in ST11), the ECU 70 advances the processing to ST10 and switches the control mode of the inverter 40 from the rectangular wave control mode to the PWM control mode.

In the evacuation running of the vehicle 1, the rectangular wave control mode is rarely selected while traveling on a flat road or an uphill. This is because the discharge power (Wout) from the battery 10 is suppressed, and high-speed running is basically not performed. The square wave control mode is selected mainly during high-speed traveling (that is, when the battery 10 is charged) accompanying a downhill.

The ECU 70 acquires the temperature Tb of the battery 10 from the battery temperature sensor 63 at the start of the rectangular wave control mode (YES in ST5), and sets the acquired temperature as the initial temperature T0 (ST6).

In ST7, the ECU 70 acquires the temperature Tb of the battery 10 from the battery temperature sensor 63. Then, the ECU 70 calculates the temperature rise amount ΔTb from the start of the rectangular wave control mode to the present. Specifically, the difference between the current temperature Tb acquired in ST7 and the initial temperature T0 acquired in ST6 can be set as the temperature rise amount ΔTb (ΔTb = Tb−T0).

The acquisition timing of the initial temperature T0 is not limited to immediately after the start of the rectangular wave control mode, but may be immediately before the start of the rectangular wave control mode (immediately before ST4), or immediately before or immediately after the start of the evacuation run (immediately before the start of the evacuation run). It may be immediately before / immediately after ST2). However, in the case of immediately before or immediately after the start of the evacuation run, the temperature rise amount (including the temperature rise amount due to the discharge of the battery 10) from the start of the evacuation run to the selection of the rectangular wave control mode is used. It is desirable to consider.

In ST8, the ECU 70 determines whether the temperature rise amount ΔTb of the battery 10 is larger than the reference amount REF. While the temperature rise amount ΔTb is equal to or less than the reference amount REF (NO in ST8), the ECU 70 returns the processing to ST3 and repeats the processing after ST3.

On the other hand, when the temperature rise amount ΔTb becomes larger than the reference amount REF (YES in ST8), the generated power (regenerative power) of the motor generator 50 is charged to the battery 10, and the heat loss (Joule heat) accompanying the charging causes the battery 10. It is highly possible that the temperature Tb has risen. Therefore, the ECU 70 determines that the resolver offset Δθ is large (ST9).

Further, the ECU 70 switches the control mode of the inverter 40 from the rectangular wave control mode to the PWM control mode (ST10). The switching destination PWM control mode may be either a sinusoidal PWM control mode or an overmodulation PWM control mode, but it is more preferable to switch to a sinusoidal PWM control mode having high responsiveness. By switching to the PWM control mode, further charging of the battery 10 can be suppressed and the battery 10 can be protected from overcharging. The process is then returned to the main routine.

As described above, in the present embodiment, when the battery 10 is prohibited from being charged (regenerative power generation of the motor generator 50) and the square wave control mode is selected as the vehicle 1 is retracted. In addition, the temperature Tb of the battery 10 is monitored. When the temperature Tb of the battery 10 rises above the reference amount REF (predetermined amount), the control mode of the inverter 40 is switched from the rectangular wave control mode to the PWM modulation control mode. By selecting the PWM modulation control mode, the influence of the resolver offset can be reduced and the generated power of the motor generator 50 can be more reliably approached to zero as compared with the case of selecting the rectangular wave control mode. Therefore, according to the present embodiment, the battery 10 can be reliably protected.

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. The scope of the present disclosure is set forth by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims.

1 vehicle, 10 batteries, 20 SMR, 30 converter, 40 inverter, 41 U-phase arm, 42 V-phase arm, 43 W-phase arm, 50 motor generator, 61 battery voltage sensor, 62 battery current sensor, 63 battery temperature sensor, 64 System voltage sensor, 65 motor current sensor, 66 resolver, 67 vehicle speed sensor, 70 ECU, 71 PWM control unit, 711 current command generation unit, 712,715 coordinate conversion unit, 713,714 PI calculation unit, 716 PWM modulation unit, 72 Rectangular wave control unit, 721 coordinate conversion unit, 723 PI calculation unit, 722 torque estimation unit, 724 switching command calculation unit, 73 control mode switching unit, C0, C1 capacitors, D1 to D8 diodes, L1 reactor, PL1, PL2 positive voltage line , NL negative voltage wire, Q1 to Q8 switching element.

Claims (1)

With a motor generator for driving,
A resolver that detects the rotation angle of the motor generator,
The inverter that drives the motor generator and
A storage battery that is charged through the inverter by the generated power of the motor generator, and
A control device having a plurality of control modes for performing feedback control of the inverter using the detected value of the resolver is provided.
The plurality of control modes are
A square wave control mode that performs torque feedback control so that a phase-controlled square wave voltage is applied to the motor generator.
It includes a pulse width modulation control mode in which current feedback control is performed so that a pulse width modulated voltage is applied to the motor generator.
When charging of the storage battery is prohibited and the square wave control mode is selected, the control device sets the control mode of the inverter to the square wave when the temperature of the storage battery rises above a predetermined amount. A vehicle that switches from the control mode to the pulse width modulation control mode.

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