Motor control system and hybrid vehicle

Abstract

Provided is a motor control system and a hybrid vehicle. The motor control system includes an MG, a battery, an SMR, and an MG-ECU. The MG-ECU is configured to control the MG according to an instruction provided through communication. Further, the MG-ECU is configured to execute autonomous power generation control of the MG in the event of a communication abnormality. The autonomous power generation control is control in which the MG-ECU causes the MG to generate power at a predetermined voltage without following the above instruction. The MG-ECU starts the autonomous power generation control after the switching of the SMR from the off state to the on state is completed when detecting a communication abnormality.

Description

Technical Field

[0001] The present disclosure relates to a motor control system, and more particularly to a motor control system including an electric generator. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2014-079081 discloses a vehicle including a relay provided in a circuit between an electric generator and a power storage device. When the relay is switched from an off state to an on state, current flows through the relay in the circuit. Summary of the Invention

[0003] When the motor control device is configured to control the electric generator according to an instruction provided through communication, the motor control device cannot receive the instruction when a communication abnormality occurs. Thus, when a communication abnormality occurs, the motor control device sometimes performs autonomous power generation control in which the electric generator generates power at a predetermined voltage without following the instruction.

[0004] When a relay is provided between the electric generator and the power storage device as in Japanese Unexamined Patent Application Publication No. 2014-079081, the relay may be damaged depending on the timing at which autonomous power generation control is started when the communication abnormality occurs as described above.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a motor control system capable of appropriately protecting a relay between an electric generator and a power storage device during execution of autonomous power generation control, and a hybrid vehicle including the system.

[0006] The motor control system of the present disclosure includes an electric generator, a power storage device, a relay, and a first control device. The electric generator is configured to generate power by receiving a rotational force. The power storage device receives the power generated by the electric generator. The relay is provided between the electric generator and the power storage device. The first control device is configured to control the electric generator according to an instruction provided through communication. Further, the first control device is configured to perform autonomous power generation control of the electric generator when a communication abnormality occurs. The autonomous power generation control is control in which the first control device causes the electric generator to generate power at a predetermined voltage without following the instruction. The first control device starts the autonomous power generation control after completion of the switching of the relay from the off state to the on state when detecting the communication abnormality.

[0007] In the above configuration, when a communication abnormality as described above occurs, the autonomous power generation control is started after completion of the switching of the relay from the off state to the on state. Therefore, it is possible to prevent a relay failure that occurs when the relay is switched from the off state to the on state during execution of the autonomous power generation control.

[0008] The motor control system may also include a second control device. The second control device is configured to communicate with the first control device and output an instruction to the first control device. The second control device controls a relay. The first control device starts autonomous power generation control when a first threshold time has elapsed since the moment when the voltage input from the power storage device to the motor generator through the relay reaches a threshold voltage. The threshold voltage is the voltage that needs to be input to the motor generator at least for the first control device to execute autonomous power generation control.

[0009] In the above configuration, even when there is a communication abnormality in which the first control device cannot obtain, through communication, information indicating that the relay has been switched from the off state to the on state by the second control device, it is possible to presume that the switching has been actually completed after the first threshold time has elapsed. Thus, even in such a communication abnormality, it is considered that the switching has been completed and autonomous power generation control is started, and therefore, relay failure can be prevented.

[0010] The motor control system may also include an internal combustion engine that generates a rotational force. The first control device starts autonomous power generation control when a second threshold time has elapsed since the moment when the rotational speed of the internal combustion engine reaches a threshold rotational speed.

[0011] In the above configuration, it is possible to start autonomous power generation control in a situation where the motor generator is actually rotating to an extent that power generation is possible.

[0012] The second control device may also diagnose whether there is an abnormality in the relay based on the voltage input to the motor generator. The moment when the first control device starts autonomous power generation control is after the diagnosis by the second control device that there is no abnormality in the relay has been completed.

[0013] In the above configuration, it is possible to avoid a situation where autonomous power generation control is started in a situation where an abnormality occurs in the relay.

[0014] In addition, the hybrid vehicle of the present disclosure includes the above-described motor control system and an internal combustion engine that generates the above-described rotational force.

[0015] According to the hybrid vehicle, in the case where the communication abnormality as described above occurs, autonomous power generation control is started after the switching of the relay from the off state to the on state is completed. Therefore, it is possible to prevent relay failure that occurs when the relay is switched from the off state to the on state during the execution of autonomous power generation control.

[0016] According to the present disclosure, it is possible to provide a motor control system that can appropriately protect a relay between a motor generator and a power storage device during the execution of autonomous power generation control. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, where like reference numerals represent like elements, and wherein:

[0018] Figure 1 is a diagram showing the overall configuration of a vehicle to which the motor control system according to the present embodiment is applied.

[0019] Figure 2 is a timing chart for explaining the processing performed for autonomous power generation control in the comparative example when a communication abnormality occurs.

[0020] Figure 3 is a timing chart for explaining the processing performed for autonomous power generation control in the present embodiment when a communication abnormality occurs.

[0021] Figure 4 is a flowchart showing an example of the processing accompanying autonomous power generation control. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In addition, the same or corresponding parts in the drawings are given the same reference numerals, and their descriptions will not be repeated.

[0023] Figure 1 is a diagram showing the overall configuration of a vehicle to which the motor control system according to the present embodiment is applied. The vehicle 10 is a so-called mild hybrid vehicle and travels by driving an internal combustion engine with the assistance of an MG (Motor Generator).

[0024] Refer to Figure 1 , the vehicle 10 includes a motor control system 100, an EFI (Electrical Fuel Injection)-ECU (Electronic Control Unit) 102, an internal combustion engine 103, rotational speed sensors 104 and 106, and a bus 137.

[0025] The motor control system 100 includes a battery 105, an SMR (System Main Relay) 110, a capacitor 115, a voltage sensor 116, an MG (Motor Generator) 120, a battery 135, a DC / DC converter 154, an MG-ECU 130, and an integrated ECU 125.

[0026] The battery 105 is a battery pack including a plurality of single cells. Each single cell is a secondary battery such as a lithium-ion battery, a lead storage battery, or a nickel-metal hydride battery. The battery 105 is shown as an example of an electricity storage device configured to perform charge and discharge. Instead of the battery 105, an electricity storage device composed of an electricity storage element such as an electric double layer capacitor may be used. The battery 105 stores electric power for driving the vehicle 10. The voltage Vb across the battery 105 is, for example, 48V.

[0027] The SMR 110 includes contacts 140, 145, and 150 and a current-limiting resistor R1. The contact 140 is provided between a power line 151 connected to the positive electrode of the battery 105 and a power line 156. The contact 145 is provided between a power line 152 connected to the negative electrode of the battery 105 and a power line 155. The contact 150 is connected in series with the current-limiting resistor R1. The contact 150 and the current-limiting resistor R1 are provided in parallel with respect to the contact 145.

[0028] The capacitor 115 is provided between the power lines 155 and 156. The voltage sensor 116 detects the voltage VC across the capacitor 115. The detection value of the voltage sensor 116 is output to the integrated ECU 125 and the MG-ECU 130 (both will be described later).

[0029] As an example, the MG 120 is a three-phase permanent magnet synchronous motor. The MG 120 is connected to the rotating shaft of the internal combustion engine 103 (described later) via a drive belt (not shown). The output torque of the MG 120 is transmitted to the rotating shaft of the internal combustion engine 103 through the drive belt and is mainly used to assist the rotation of the internal combustion engine 103.

[0030] In addition, the MG 120 is electrically connected to the power lines 155 and 156 through the power line 170. The MG 120 is configured to generate electricity using the rotational force received via the drive belt during regenerative braking of the vehicle 10 or when power generation is required. The electric power generated by the MG 120 is stored in the battery 105. The MG 120 is configured to generate electricity by receiving the electric power of the voltage VC when the voltage VC of the power line 170 is equal to or higher than a threshold voltage (described later).

[0031] The battery 135 is a battery for auxiliary machines (e.g., 12V). The battery 135 supplies operating power to the EFI-ECU 102, the integrated ECU 125, and the MG-ECU 130 (all will be described later) through the power line 158. In addition, the battery 135 receives power supply from the DC / DC converter 154.

[0032] The DC / DC converter 154 is provided between the power lines 155 and 156 and the power line 158. The DC / DC converter 154 is configured to step down (convert) the power output from the battery 105 and output it to the power line 158. The stepped-down power is stored in the battery 135. The DC / DC converter 154 operates according to a control instruction from the integrated ECU 125.

[0033] The MG-ECU 130 is configured to control the MG 120 according to an instruction (such as a torque instruction) provided from the integrated ECU 125 through communication. When communication is established between the MG-ECU 130 and the integrated ECU 125, the MG-ECU 130 can receive information from the integrated ECU 125 indicating which state of the relay 110 is in the on state or the off state. The MG-ECU 130 can receive this instruction and this information via a bus 137 that communicates through CAN (Controller Area Network). The MG-ECU 130 includes a processor such as a CPU (Central Processing Unit) and a memory (not shown in the figure) composed of a ROM (ReadOnly Memory) and a RAM (Random Access Memory).

[0034] The internal combustion engine 103 is, for example, a gasoline engine or a diesel engine. By the rotation of the internal combustion engine 103, the driving force for the vehicle 10 to travel is generated. The internal combustion engine 103 is connected to the MG 120 by a belt. Therefore, during the travel of the vehicle 10, the rotation of the internal combustion engine 103 can be assisted by the rotation of the MG 120 via the belt. When the vehicle 10 system is started, the internal combustion engine 103 starts to rotate by the operation of a starter (not shown) for starting the internal combustion engine 103.

[0035] The EFI-ECU 102 controls the internal combustion engine 103. When the vehicle 10 system is started and the rotational speed of the internal combustion engine 103 exceeds a threshold rotational speed, the EFI-ECU 102 starts fuel injection of the internal combustion engine 103 to start the internal combustion engine 103.

[0036] The rotational speed sensor 104 detects the rotational speed (rotational speed per unit time) of the internal combustion engine 103. This rotational speed is output to the EFI-ECU 102 and the integrated ECU 125.

[0037] The rotational speed sensor 106 detects the rotational speed of the MG 120. The detection value of the rotational speed sensor 106 is output to the MG-ECU 130.

[0038] The integrated ECU 125 controls the entire vehicle 10. The integrated ECU 125 controls, for example, the open / closed states of contacts 140, 145, and 150 in the SMR 110. As an example, when the system of the vehicle 10 is started (when contacts 140, 145, and 150 are open), the integrated ECU 125 diagnoses whether there is adhesion at contact 140 by closing contact 145 or 150 (conducting).

[0039] When contact 145 or 150 is closed in this way, when the detected value (voltage VC) of the voltage sensor 116 starts to rise, the integrated ECU 125 diagnoses that contact 140 is adhered. On the other hand, when voltage VC does not rise in the above situation, the integrated ECU 125 diagnoses that contact 140 is not adhered.

[0040] Next, the integrated ECU 125 diagnoses whether there is adhesion at contact 145 or 150 in the same way as the above detected value by closing contact 140 after disconnecting the closed contact 145 or 150.

[0041] After diagnosing the adhesion of contact 145 or 150, the integrated ECU 125 further closes contact 150. Thereby, while restricting the current flowing in the capacitor 115 through the limiting resistor R1, pre-charging of the capacitor 115 is performed. This pre-charging is performed to reduce the inrush current flowing in the capacitor 115 when the integrated ECU 125 closes contact 145. The integrated ECU 125 determines whether the pre-charging of the capacitor 115 has started based on whether the detected value of the voltage sensor 116 rises.

[0042] When the detected value of the voltage sensor 116 does not rise, the integrated ECU 125 determines that the pre-charging of the capacitor 115 has not started. In this case, it is considered that as a result of a disconnection between power lines 151 and 156 or between power lines 152 and 155 or a failure in the wiring between the integrated ECU 125 and the SMR 110, the control signal is not transmitted from the integrated ECU 125 to the SMR 110, and contact 150 of the SMR 110 remains in the open state. Therefore, in the above situation, the integrated ECU 125 diagnoses that there is an abnormality in the SMR 110.

[0043] On the other hand, when the detected value of the voltage sensor 116 rises, the integrated ECU 125 determines the start of the pre-charging of the capacitor 115. Then, based on the situation that the detected value of the voltage sensor 116 has risen to the voltage Vb of the battery 105, the integrated ECU 125 determines the end of the pre-charging of the capacitor 115. Next, the integrated ECU 125 closes contact 145 and disconnects contact 150. Thereby, the switching of the SMR 110 from the off state to the on state is completed.

[0044] In addition, the "open state" of the SMR110 means a state in which at least two of the contacts 140, 145, and 150 are open. Further, the "closed state" of the SMR110 means a state in which both of the contacts 140 and 145 are closed and the contact 150 is open. Additionally, during the pre-charging of the capacitor 115 when the vehicle 10 system is started and until the SMR110 switches from the open state to the closed state, the SMR110 assumes a "semi-closed state" (a state in which the contacts 140 and 150 are closed and the contact 145 is open).

[0045] As described above, the integrated ECU 125 appropriately opens and closes the contacts 140, 150, and 145 when the vehicle 10 system is started. And during the opening and closing of these contacts, based on the voltage VC detected by the voltage sensor 116, it is diagnosed whether an abnormality (such as adhesion, disconnection, or wiring failure, etc.) has occurred in the SMR110. In the case where an abnormality occurs in the SMR110, the integrated ECU 125 outputs an instruction to the MG-ECU 130 to stop the MG120, for example.

[0046] The integrated ECU 125 is electrically connected to each of the ECUs of the EFI-ECU 102 and the MG-ECU 130 via the bus 137. The integrated ECU 125 is configured to communicate with these ECUs via the bus 137 and control the entire vehicle 10 by outputting instructions to these ECUs.

[0047] The integrated ECU 125 is configured to output a torque command value for the MG120 to the MG-ECU 130. The MG-ECU 130 drives the MG120 based on this torque command value. Additionally, the integrated ECU 125 is configured to output the state of the SMR110 (for example, which state among the closed state, semi-closed state, or open state the SMR110 is in) to the MG-ECU 130. Furthermore, the integrated ECU 125, like the MG-ECU 130, includes a processor such as a CPU and a memory (not shown in the figure) composed of a ROM, a RAM, etc.

[0048] In addition, when the vehicle 10 system is started, the integrated ECU 125 outputs an instruction for starting the internal combustion engine 103 to the EFI-ECU 102.

[0049] In the case where a communication abnormality occurs between the MG-ECU 130 and the integrated ECU 125, the MG-ECU 130 cannot receive an instruction from the integrated ECU 125 via the bus 137. Thus, in this case, the MG-ECU 130 sometimes performs autonomous power generation control to generate power at a predetermined voltage for the MG120 without following this instruction.

[0050] Here, when such a communication anomaly occurs, SMR110 may be damaged according to the timing at which autonomous power generation control starts. Therefore, when performing autonomous power generation control during the above-mentioned communication anomaly, it is desirable to appropriately protect SMR110.

[0051] Then, in the present embodiment, a method of control by MG-ECU130 for appropriately protecting SMR110 in such a case is shown. First, before explaining the method of this control, a comparative example in the case where this control is not performed will be described.

[0052] Figure 2 It is a timing chart for explaining the processing performed in the comparative example along with autonomous power generation control during a communication anomaly.

[0053] At Figure 2 In, the horizontal axis represents time. The vertical axis, starting from the top, successively represents the on (ON) / off (OFF) of the ignition switch, the presence or absence of startup of the motor control system 100, whether a communication anomaly is detected in the MG-ECU, whether the switching of SMR110 from the off state to the on state has started, whether the switching has been completed, the rotational speed of the internal combustion engine 103, the voltage VC of the power line 170, and whether autonomous power generation control by the MG-ECU is being performed (execution (ON) / non-execution (OFF) of this control).

[0054] At time t1, the state of the ignition switch changes from off to on (line 205).

[0055] At time t2, in response to the switching of the above switch, the motor control system 100 (including the integrated ECU and the MG-ECU) and the EFI-ECU102 start (line 210). And the integrated ECU starts the diagnosis of whether there is an anomaly in SMR110 according to the voltage VC ( Figure 1 ) detected by the voltage sensor 116 (line 230). This diagnosis continues until time tA. In Figure 2 's example, no anomaly occurs in SMR110. In addition, time tA is determined based on the time required for the completion of the diagnosis that there is no anomaly in SMR110 and the time t2 when this diagnosis started.

[0056] At time t3, the MG-ECU detects that a communication anomaly has occurred with the integrated ECU (line 215). The MG-ECU determines that a communication anomaly has occurred, for example, based on the inability to receive an instruction from the integrated ECU.

[0057] At time t4, the integrated ECU responds to the startup of the motor control system 100 at time t2 and starts the switching of the SMR110 from the off state to the on state (line 220). Here, the switching of the SMR110 from the off state to the on state refers to a series of operations (line 322) in which the contacts 140, 145, and 150 are appropriately opened and closed during the period from the moment when the pre-charge in the capacitor 115 occurs and the contact 140 is closed (the SMR110 switches from the off state to the semi-on state) to the moment when the contact 150 is opened (the SMR110 switches from the semi-on state to the on state).

[0058] Specifically, at time t4, the integrated ECU closes the contact 140 in the state where the contacts 140, 145, and 150 of the SMR110 are open. And the integrated ECU diagnoses whether there is adhesion in the contact 145 or 150 during the period from time t4 to time t7 (described later).

[0059] At time t5, the integrated ECU outputs an instruction for starting the internal combustion engine 103 to the EFI-ECU 102. The EFI-ECU 102 operates the starter in accordance with this instruction in order to start the internal combustion engine 103. As a result, the rotational speed NR of the internal combustion engine 103 starts to rise (line 225). After the rotational speed NR rises to a predetermined value NP, the state where the rotational speed NR is the predetermined value NP continues.

[0060] At time t7 when the adhesion diagnosis of the contacts 145 and 150 is completed, the integrated ECU closes the contact 150 of the SMR110. As a result, the SMR110 switches from the off state to the semi-on state. And the pre-charge in the capacitor 115 starts and the voltage VC starts to rise (line 230). And the integrated ECU diagnoses whether there is an abnormality such as a broken wire in the SMR110 in accordance with the detected value (voltage VC) of the voltage sensor 116.

[0061] At time t8, the voltage VC reaches the threshold voltage VTH (line 230). The threshold voltage VTH is the voltage that needs to be input to the MG120 from the power line 170 at least in order for the MG120 to generate electricity through autonomous power generation control. In this comparative example, at time t8 when the voltage VC reaches the threshold voltage VTH, the MG-ECU starts autonomous power generation control (line 250).

[0062] Here, at time t8, although the contacts 140 and 150 are closed, the SMR 110 is in a semi-conducted state, and the voltage VC of the power line 170 has not yet risen to the voltage Vb (line 230). Therefore, when the predetermined voltage output from the MG 120 through the self-power generation control is higher than the voltage VC (threshold voltage VTH) of the power line 170 at time t8 when the self-power generation control starts, immediately after the start of the self-power generation control, an excessive current may flow sharply from the MG 120 to the contacts 140 and 150 through the power line 170.

[0063] Thus, when a communication abnormality occurs between the integrated ECU and the MG-ECU, when starting the self-power generation control at time t8 when the SMR 110 is in a semi-conducted state as in the comparative example, it may not be possible to appropriately protect the SMR 110.

[0064] Then, in the present embodiment, when a communication abnormality occurs between the integrated ECU 125 and the MG-ECU 130, after the switching of the SMR 110 from the off state to the on state (a series of switches from the off state → semi-conducted state → on state) is completed, the MG-ECU 130 starts the self-power generation control.

[0065] Therefore, in the present embodiment, the potential difference between the voltage VC at the start of the self-power generation control and the predetermined voltage output from the MG 120 through the self-power generation control is smaller than that in the comparative example ( Figure 2 ). Therefore, immediately after the start of the self-power generation control, the current flowing from the MG 120 to the contacts 140 and 150 is smaller than that in the comparative example ( Figure 2 ). As a result, it is possible to appropriately protect the SMR 110 during the self-power generation control by the MG-ECU 130.

[0066] Here, after time t3, a communication abnormality occurs between the integrated ECU 125 and the MG-ECU 130. Therefore, the MG-ECU 130 cannot obtain from the integrated ECU 125 through the bus 137 ( Figure 1 ) the information that the switching of the SMR 110 from the off state to the on state by the integrated ECU 125 has been completed. That is, although it is desirable to start the self-power generation control after the completion of the switching from the viewpoint of protecting the SMR 110, the MG-ECU 130 cannot obtain from the integrated ECU 125 when the above switching has been completed due to the above communication abnormality. As a result, the MG-ECU 130 cannot obtain from the integrated ECU 125 the information indicating the time for starting the self-power generation control.

[0067] Therefore, the following describes the method: In order to protect the SMR110 when performing autonomous power generation control during a communication anomaly, the MG-ECU130 estimates the time when this switching is successfully completed.

[0068] Figure 3 It is a timing chart for explaining the processing performed during autonomous power generation control accompanying a communication anomaly in the present embodiment.

[0069] In Figure 3 the horizontal axis represents time. The vertical axis, starting from the top, successively represents the on / off state of the ignition switch, the presence or absence of activation of the motor control system 100, whether a communication anomaly is detected in the MG-ECU130, whether the switching of the SMR110 from the off state to the on state has started, whether this switching has been completed, the rotational speed of the internal combustion engine 103, the voltage VC of the power line 170, and the execution / non-execution of autonomous power generation control based on the MG-ECU130.

[0070] In addition, in the present embodiment, in the MG-ECU130, the rotational speed NR of the internal combustion engine 103 is calculated based on the detection value of the rotational speed sensor 106. The MG120 and the rotational shaft of the internal combustion engine 103 are connected by a transmission belt, and the MG-ECU130 can calculate the rotational speed NR of the internal combustion engine 103 based on the detection value of the rotational speed sensor 106.

[0071] In the present embodiment, the processing of the EFI-ECU102, the integrated ECU125, and the MG-ECU130 during the period from time t1 to time t5 and at time t7 is the same as that processing in the foregoing comparative example ( Figure 2 ) (lines 205 to 230).

[0072] At time t6, the rotational speed NR of the internal combustion engine 103 reaches the threshold rotational speed NTH (line 225). This threshold TH is, for example, the lowest idle speed (the lowest rotational speed of the internal combustion engine 103 when the internal combustion engine 103 is driven in a no-load state). When the rotational speed NR exceeds the threshold rotational speed NTH, the integrated ECU125 outputs an instruction to the EFI-ECU102 to start the internal combustion engine 103. The EFI-ECU102 starts fuel injection of the internal combustion engine 103 according to this instruction to start the internal combustion engine 103. Subsequently, after the rotational speed NR rises to a predetermined value NP, the state where the rotational speed NR is the predetermined value NP continues.

[0073] In the present embodiment, the elapsed time from when the rotational speed NR of the internal combustion engine 103 reaches the threshold rotational speed NTH (from the start of the internal combustion engine 103) is used as described later for the MG-ECU130 to estimate whether the MG120 has rotated sufficiently to be able to generate electricity.

[0074] At time t9, the integrated ECU 125 completes the switching of the SMR 110 from the off state to the on state (line 322). Specifically, after the pre-charging of the capacitor 115 is completed, the integrated ECU 125 closes the contact 145 and opens the contact 150 in the semi-on state of the SMR 115 where the contacts 140 and 150 are closed. As a result of the SMR 115 switching from the semi-on state to the on state, the switching of the SMR 110 from the off state to the on state is completed.

[0075] Here, after time t9, the pre-charging of the capacitor 115 has been completed, so the voltage VC rises to the voltage Vb. Therefore, the voltage VC (voltage Vb) at the start of the self-power generation control after time t9 is higher than the voltage VC (threshold voltage VTH) at time t8 in the case of the comparative example. Therefore, after time t9, the potential difference between the voltage VC at the start of the self-power generation control and the predetermined voltage output from the MG 120 through the self-power generation control is smaller than that in the comparative example.

[0076] Thus, when the self-power generation control starts after time t9, the current flowing from the MG 120 to the contacts 140 and 150 is smaller than that in the comparative example immediately after the start of this control. Therefore, when the self-power generation control starts after time t9, the degree of consumption of the SMR 110 can be reduced compared to the case where the control starts at time t8 as in the comparative example.

[0077] Here, as described above, the MG-ECU 130 cannot obtain the information (line 322) that the switching of the SMR 110 from the off state to the on state has been completed by the integrated ECU 125 at time t9 as described above through the bus 137 ( Figure 1 ).

[0078] Therefore, a method for appropriately determining the timing for the MG-ECU 130 to start the self-power generation control even in the case of the communication abnormality as described above will be described below.

[0079] In order to appropriately protect the SMR 110 differently from the case of the comparative example, the SMR 110 only needs to be switched to the on state at the start of the self-power generation control. Specifically, at the start of the self-power generation control, it is sufficient that the voltage VC of the power line 170 reaches the voltage Vb.

[0080] Therefore, in the present embodiment, when the first condition that the threshold time TTH1 has elapsed since the time t8 when the voltage VC of the power line 170 reaches the threshold voltage VTH is satisfied, the MG-ECU 130 presumes that the switching of the SMR 110 from the off state to the on state is completed.

[0081] Here, the threshold time TTH1 is appropriately predetermined such that when the elapsed time from time t8 is equal to or greater than the threshold time TTH1, the voltage VC of the power line 170 has surely reached a voltage Vb greater than the threshold voltage VTH. Therefore, when the elapsed time from time t8 is equal to or greater than the threshold time TTH1, the MG-ECU 130 can presume that the switching of the SMR 110 from the off state to the on state has surely been completed (i.e., the time after the threshold time TTH1 has elapsed from time t8 is surely after time t9). Thus, in this case, the MG-ECU 130 can protect the relay 110 when starting the self-power generation control.

[0082] In addition, the self-power generation control is preferably started when the MG 120 is fully rotated to a state where power generation is possible. Therefore, the MG-ECU 130 may also start the self-power generation control when the condition that sufficient time has elapsed since the start of the internal combustion engine 103 is further satisfied. Specifically, the MG-ECU 130 may start the self-power generation control when, in addition to the above-described first condition, the second condition that the threshold time TTH2 has elapsed from the time t6 (the start time of the internal combustion engine 103) when the rotational speed NR of the internal combustion engine 103 has reached the threshold rotational speed NTH is satisfied.

[0083] Here, the threshold time TTH2 is appropriately predetermined such that when the elapsed time from time t6 is equal to or greater than the threshold time TTH2 (second condition), the rotational speed NR of the internal combustion engine 103 has surely reached the predetermined value NP. By determining the threshold time TTH2 in this way, it is considered that the MG 120 connected to the internal combustion engine 103 is in a state where it is fully rotated to a state where power generation is possible in the above-described case.

[0084] For example, in a situation where the rotational speed NR has not reached the threshold rotational speed NTH (the internal combustion engine 103 has not started), the MG 120 is not in a state where it receives the rotational force transmitted from the internal combustion engine 103 through the belt and is fully rotated to a state where power generation is possible. Therefore, the time when the MG-ECU 130 starts the self-power generation control is preferably after the time t6 when the rotational speed NR has reached the threshold rotational speed NTH.

[0085] As described above, by determining the threshold times TTH1 and TTH2, the MG-ECU 130 can presume that the switching of the SMR 110 from the off state to the on state has surely been completed (first condition) in a situation where the MG 120 is fully rotated to a state where power generation is possible (second condition) at the time t10 after these times have elapsed. Thus, the MG-ECU 130 determines the time t10 as the time for starting the self-power generation control.

[0086] Further, the MG-ECU 130 starts the self-power generation control of the MG 120 at time t10 (line 350). As a result, the SMR 110 can be appropriately protected as compared with the case of the comparative example (the one-dot chain line 250).

[0087] In addition, in the Figure 3 example, for simplicity of explanation, it is assumed that the time point after the threshold time TTH1 has elapsed from time t8 and the time point after the threshold time TTH2 has elapsed from time t6 are the same time t10, but these time points may also be different. In this case, the MG-ECU 130 determines, for example, either one of these time points as the time for starting the self-power generation control.

[0088] During the period from time t2 to time tA, the integrated ECU 125 performs diagnosis of whether there is an abnormality (sticking, disconnection, etc.) in the SMR 110. Different from the Figure 3 example, in this period, if an abnormality occurs in the SMR 110, it is not good to start the self-power generation control by the MG-ECU 130. Specifically, in the above case, the integrated ECU 125 may not be able to switch the supply / cut-off of the power between the battery 105 and the MG 120, and thus it is considered not good to start the self-power generation control.

[0089] Therefore, it is preferable that the time t10 for starting the self-power generation control is after the time tA when the diagnosis that the SMR 110 has no abnormality is completed.

[0090] Then, the threshold times TTH1 and TTH2 are appropriately determined in advance so that the time t10 is after the time tA when the diagnosis that the SMR 110 has no abnormality is completed. Thereby, the self-power generation control of the MG 120 is started only after the time tA when the diagnosis that the SMR 110 has no abnormality is completed. As a result, it is possible to avoid starting the self-power generation control in a situation where an abnormality occurs in the SMR 110.

[0091] Figure 4 is a flowchart showing an example of the process accompanying the self-power generation control. In the following description, appropriately refer to Figure 3 . This flowchart is executed when the system of the vehicle 10 is started.

[0092] In step S105, the MG-ECU 130 determines whether a communication abnormality occurs between the MG-ECU 130 and the integrated ECU 125. When no communication abnormality occurs between the MG-ECU 130 and the integrated ECU 125 (step S105: NO), the MG-ECU 130 performs normal control on the MG 120 (step S125). Specifically, the MG-ECU 130 performs according to the bus 137 (Figure 1 ) Controls the MG120 based on the instruction received from the integrated ECU125. Then, the process transfers back. On the other hand, in the case of a communication abnormality (step S105: Yes), the process transfers to step S107.

[0093] In step S107, the integrated ECU125 starts switching the SMR110 from the off state to the on state. Specifically, with the contacts 140, 145, and 150 of the SMR110 open, the contact 140 is closed. Then, the process transfers to step S110.

[0094] Here, the MG-ECU130 cannot obtain from the integrated ECU125 information indicating whether the switching of the SMR110 from the off state to the on state has been completed due to the above communication abnormality. Therefore, in step S110 and subsequent step S115, by determining whether the aforementioned first condition and second condition are respectively satisfied, it is presumed whether the switching has been completed in a situation where the MG120 has rotated sufficiently to be able to generate electricity.

[0095] In step S110, the MG-ECU130 determines whether the threshold time TTH1 has elapsed since the time t8 when the voltage VC of the power line 170 reached the threshold voltage VH (first condition). If the threshold time TTH1 has elapsed since the time t8 (step S110: Yes), the MG-ECU130 presumes that the switching of the SMR110 from the off state to the on state has been successfully completed, and the process transfers to step S115. If not (step S110: No), the determination process of step S110 is repeated until the threshold time TTH1 has elapsed since the time t8.

[0096] In step S115, the MG-ECU130 determines whether the threshold time TTH2 has elapsed since the time t6 when the rotational speed NR of the internal combustion engine 103 calculated from the detection value of the rotational speed sensor 106 reached the threshold rotational speed NTH (second condition). If the threshold time TTH2 has elapsed since the time t6 (step S115: Yes), the MG-ECU130 presumes that the MG120 has rotated sufficiently to be able to generate electricity, and the process transfers to step S117. If not (step S115: No), the determination process of step S115 is repeated until the threshold time TTH2 has elapsed since the time t6.

[0097] In step S117, based on the fact that the time t10 satisfying both the first condition and the second condition has arrived, the MG-ECU 130 presumes that the switching of the SMR 110 from the off state to the on state has been successfully completed under the condition that the MG 120 has rotated sufficiently to be able to generate electricity. Then, the MG-ECU 130 starts the self-power generation control of the MG 120 (step S120). Then, a series of processes end.

[0098] As described above, when a communication abnormality occurs between the MG-ECU 130 and the integrated ECU 125 in the present embodiment, after the switching of the SMR 110 from the off state to the on state is completed, the self-power generation control is started. Thereby, when the self-power generation control can be executed during a communication abnormality as described above, the SMR 110 can be appropriately protected.

[0099] [Modification Example]

[0100] In the present embodiment, the vehicle 10 is a hybrid vehicle equipped with the internal combustion engine 103. In other embodiments, the vehicle 10 may be an electric vehicle not equipped with the internal combustion engine 103. In this case, instead of the internal combustion engine 103 and the aforementioned drive belt, another MG (not shown) different from the MG 120 and a power transmission mechanism for transmitting the rotational force of the other MG to the MG 120 are provided.

[0101] Moreover, when a communication abnormality occurs between the MG-ECU 130 and the integrated ECU 125, the other MG rotates, and via the power transmission mechanism, the MG 120 also rotates. Thus, even when the internal combustion engine 103 is not provided, the MG 120 can rotate sufficiently to be able to generate electricity. Therefore, the MG-ECU 130 can execute the self-power generation control in the same manner as in the above-described embodiment.

[0102] In addition, in the above-described embodiment, the vehicle 10 is a so-called mild hybrid vehicle, but it may also be a hybrid vehicle equipped with a general high-voltage battery for driving (e.g., 200V).

[0103] In addition, in the above-described embodiment, CAN is used as the communication protocol in the bus 137, but other communication protocols may be used instead of CAN.

[0104] In addition, in the above-described embodiment, the MG-ECU 130 calculates the rotational speed NR of the internal combustion engine 103 based on the detection value of the rotational speed sensor 106, but the detection value of the rotational speed sensor 104 may also be taken in.

[0105] In addition, in Figure 4In the flowchart, the start of the switching of the SMR 110 from the off state to the on state by the integrated ECU 125 (step S107) may also be before the determination of whether there is a communication abnormality (step S105).

[0106] The embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the present invention is represented by the claims, not by the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A motor control system, comprising: An electric generator configured to generate electricity by receiving a rotational force; A power storage device that receives the electricity generated by the electric generator; A relay disposed between the electric generator and the power storage device; and A first control device configured to control the electric generator according to an instruction provided through communication, The first control device is configured to perform autonomous power generation control of the electric generator in the event of an abnormality in the communication, The autonomous power generation control is control in which the first control device causes the electric generator to generate electricity at a predetermined voltage without following the instruction, In the event of detecting an abnormality in the communication, the first control device starts the autonomous power generation control after the switching of the relay from the off state to the on state is completed, The motor control system further includes a second control device configured to communicate with the first control device and output the instruction to the first control device, The second control device controls the relay, The first control device starts the autonomous power generation control when a first threshold time has elapsed since the time when the voltage input from the power storage device to the electric generator through the relay reaches a threshold voltage, The threshold voltage is the voltage that needs to be input to the electric generator at least for the first control device to perform the autonomous power generation control.

2. The motor control system according to claim 1, Further comprising an internal combustion engine that generates the rotational force, The first control device starts the autonomous power generation control when a second threshold time has elapsed since the time when the rotational speed of the internal combustion engine reaches a threshold rotational speed.

3. The motor control system according to claim 1 or 2, The second control device diagnoses whether there is an abnormality in the relay based on the voltage input to the electric generator, The time when the first control device starts the autonomous power generation control is after the diagnosis by the second control device that there is no abnormality in the relay is completed.

4. A hybrid vehicle, comprising: The motor control system according to any one of claims 1 to 3; and An internal combustion engine that generates the rotational force.

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