JP2021044968A - Motor control device - Google Patents

Abstract

To provide a motor control device that restarts after recovering from low voltage even if an internal reset occurs in one system due to cranking.SOLUTION: In a case where an internal reset occurs in one of systems A and B when a battery voltage drops due to cranking and communication between CPUs is disrupted, the other system shifts to a standby state until a state in which a battery voltage value is equal to or more than a predetermined threshold value continues for a specified time or a specified condition is established. When one of the control systems recovers from the battery voltage drop and restores, a normal motor drive operation is resumed in both systems A and B.SELECTED DRAWING: Figure 1

Description

The present invention relates to, for example, a motor control device for electric power steering having a redundant configuration including a plurality of systems of motor control circuits.

In recent years, vehicles have been equipped with functions such as idle stop to reduce fuel consumption and environmental pollution due to exhaust, but the battery voltage drops significantly due to power consumption due to cranking when the engine is restarted. Power reset in the control unit (CPU etc.) by In particular, power reset becomes a problem when the battery is deteriorated due to aging or the like.

As a technique for avoiding power reset of the control unit, for example, the motor control device of Patent Document 1 has a charging / discharging mechanism that charges and discharges the charge of the inverter voltage supplied to the inverter, and a separation means that separates the charging / discharging mechanism from the power supply voltage. When the power supply voltage drops, the charging / discharging mechanism is separated from the power supply voltage by the separation means, and a voltage is applied from the charging / discharging mechanism to the control unit to avoid the power supply reset of the control unit. Discloses a configuration that prevents such things from disappearing.

On the other hand, in an electric power steering device equipped with a motor control device, two sets of inverter circuits for independently driving two sets of coil windings provided in the motor are provided, and control circuits other than the inverter circuit are made into a dual system. However, a redundant configuration has been conventionally known in which motor control is continued by the other system that is operating normally even if one system becomes abnormal due to a component failure or the like.

Japanese Patent No. 6137414

Patent Document 1 presents a method of avoiding a power reset of a control unit (MCU) of a motor control device, but mentions a motor control method when a reset of the control unit occurs due to a voltage drop due to cranking or the like. Not done. Therefore, there is a problem that it is not possible to avoid a situation in which control is stopped due to a voltage drop.

In a motor control device that performs redundant control using a plurality of control units (CPUs) described above, if the battery voltage drops during cranking, a CPU reset occurs due to a constant voltage in only one system, and communication between CPUs is interrupted. there is a possibility. Although such an event is not a system failure, it is erroneously recognized as a failure of one system due to the interruption of communication between CPUs, and it shifts to fail operation, for example, the maximum output of motor control decreases. There is a problem that it becomes a degenerate operation of.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is that in a motor control device having a redundant configuration, even if a power reset of a control unit occurs in one system due to a decrease in power supply voltage due to cranking. The present invention is to provide a motor control device mounted on a vehicle or the like, which enables stable motor control.

The following configuration is provided as a means for achieving the above object and solving the above-mentioned problem. That is, the first exemplary invention of the present application is a motor control device that receives power from a battery and is composed of a plurality of control systems and drives an electric motor by a control unit provided for each of the plurality of control systems. A battery voltage detection unit that detects the voltage value of the battery, a drive voltage detection unit that detects the drive voltage value of the control unit, and an internal unit with respect to the control unit based on the detection results of the drive voltage detection unit. A reset unit for resetting and a communication status monitoring unit for monitoring the presence or absence of communication between the control units are provided, the internal reset occurs in one of the plurality of control systems, and the communication status monitoring unit performs the internal reset. When it is determined that the communication between the control units is interrupted, the other system of the plurality of control systems is in a standby state for transition to a predetermined fail operation, and after the specified conditions are satisfied, the drive control of the electric motor is performed. It is characterized by resuming.

The second exemplary invention of the present application is an electric power steering system, characterized in that the motor control device according to the first exemplary invention is provided.

An exemplary third invention of the present application is a one-system failure in a motor control device that receives power from a battery and is composed of a plurality of control systems and drives an electric motor by a control unit provided for each of the plurality of control systems. The diagnostic method is a step of detecting the voltage value of the battery, a step of detecting the drive voltage value of the control unit, and an internal reset of the control unit based on the detection result of the drive voltage value. In the step of performing, the step of monitoring the presence or absence of communication between the control units, and the step of detecting the battery voltage, the voltage value of the battery is detected to be equal to or lower than a predetermined threshold value, and the internal reset is performed in one of the plurality of control systems. Is generated, and when it is determined in the communication monitoring step that the communication between the control units is in a state of interruption, the step of diagnosing that a failure has occurred in the one system is provided.

According to the present invention, when an internal reset occurs in one system due to cranking in a motor control device having a redundant configuration and communication between control units is interrupted, the motor control device shifts to a standby state and one system recovers from a low voltage. By restarting later, normal control operation can be resumed in both systems.

FIG. 1 is a diagram showing a detailed configuration of a motor control device according to an embodiment of the present invention. FIG. 2 is a flowchart showing a processing procedure in the control unit (CPU) of the motor control device. FIG. 3 is a diagram showing an example of a battery voltage range and a control mode in the motor control device. FIG. 4 is a diagram showing a schematic configuration of an electric power steering device equipped with the motor control device according to the embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a detailed configuration of a motor control device according to an embodiment of the present invention. As shown in FIG. 1, the motor control device according to the present embodiment has a redundant configuration including a plurality of motor control systems having the same components.

Here, a motor control device having a redundant configuration of two systems will be described as an example, but it is also possible to develop a redundant configuration having a plurality of systems such as three systems and four systems.

The motor control devices 1a and 1b are composed of two independent systems each having a control unit (CPU) 12a and 12b. The motor control devices 1a and 1b include an electric motor 15 having two sets of three-phase windings (Ua, Va, Wa) 15a and three-phase windings (Ub, Vb, Wb) 15b, and two sets of three-phase windings. It has a double inverter configuration consisting of two sets of inverter circuits 14a and 14b that supply drive current to each line. The electric motor 15 is, for example, a three-phase brushless DC motor.

Hereinafter, the component including the motor control device 1a and the three-phase winding 15a is referred to as the first system (also referred to as system A), and the component including the motor control device 1b and the three-phase winding 15b is referred to as the second system (system). Also called B). The first system may be positioned as the main system and the second system may be positioned as the sub system in the entire apparatus.

In the motor control device 1a of the system A, the control unit (CPU) 12a is, for example, a microprocessor that controls the entire device. The inverter control unit 13a functions as an FET drive circuit that generates a motor drive signal from a control signal from the CPU 12a. The inverter circuit 14a is a motor drive unit that supplies a drive current to the three-phase windings (Ua, Va, Wa) 15a of the electric motor 15.

Similarly, the motor control device 1b of the system B is an inverter control unit 13b and an electric motor 15 that generate a motor drive signal from a control signal from the control unit (CPU) 12b that controls the entire device and function as an FET drive circuit. Includes an inverter circuit 14b that supplies a predetermined drive current to the three-phase windings (Ub, Vb, Wb) 15b.

The power supply unit (not shown) of the motor control devices 1a and 1b converts the battery voltage (+ B) supplied from the battery BT into a predetermined voltage (for example, a logic level voltage), and converts it into the CPU 12a, 12b and the inverter. It is supplied as an operating power source for the control units 13a and 13b.

The CPU 12a incorporates a low voltage detection unit (LVI) 33a and an internal reset circuit 35a. The low voltage detection unit (LVI) 33a (corresponding to the "drive voltage detection unit" in the claims) is a low voltage detection unit by the CPU 12a, and detects that the operating voltage of the CPU 12a has become low. Has a function. _{That is, when the voltage of the operating power supply VCC} supplied from the power supply unit (not shown) is detected and the voltage value of the operating power supply _VCC is lower than a predetermined value, the internal reset circuit 35a (“reset unit” in the scope of the patent claim A reset signal is given to the CPU 12a from (corresponding to)), so that a low voltage reset occurs in the system A.

The likewise lineage B CPU 12b, a low voltage detector (LVI) 33b and an internal reset circuit 35b is incorporated, when the voltage value of the operating power supply _{V CC} is lower than the predetermined value, the reset signal from the internal reset circuit 35b , System B becomes the system that generates the low voltage reset.

The low voltage detector (LVI), when the voltage value of the operating power supply V _CC detects that a low voltage, and outputs a low voltage detection signal. The ECM (Error Control Module) mounted on the CPU determines to perform an internal reset based on the low voltage detection signal from the LVI if the internal reset is set in advance with the low voltage detection signal.

The motor control devices 1a and 1b are configured to detect the voltage of the battery BT by the BT voltage detection units 20a and 20b and the CPUs 12a and 12b. Therefore, the BT voltage detection units 20a and 20b convert the input battery voltage into an analog voltage in a range that can be detected by the CPUs 12a and 12b by a voltage monitor circuit (voltage conversion circuit) configured by hardware.

For example, when the actual voltage (+ B) of the battery BT is 0 to 39V, the BT voltage detection units 20a and 20b convert the actual voltage into a voltage 0 to 5V that the CPUs 12a and 12b can detect AD (analog-digital). And output.

The CPUs 12a and 12b use the built-in AD converter to convert the input voltage from the BT voltage detection units 20a and 20b into a value recognizable by software. Specifically, the input voltage 0 to 5 V is converted into a voltage value of 4096 steps of 0 to 4095 in 12-digit binary notation. When the conversion value of the AD converter is 4095, this value corresponds to the AD detection voltage of 5V, so that the actual voltage of the battery can be determined to be 39V.

When the battery voltage is a voltage at which the CPUs 12a and 12b cannot normally operate, the low voltage detection function of the CPUs 12a and 12b causes a reset, so that the CPUs 12a and 12b do not detect AD of the battery voltage.

Power for driving the motor is supplied to the inverter circuit 14a from the external battery BT via the filter 16a and the power relay 17a. Further, the inverter circuit 14b is supplied with power for driving the motor from the external battery BT via the filter 16b and the power relay 17b. The filters 16a and 16b may be included in the inverter circuits 14a and 14b, respectively.

The filters 16a and 16b are composed of an electrolytic capacitor and a coil (not shown), absorb noise and the like contained in the power supply, and smooth the power supply voltage. The power supply relays 17a and 17b are composed of, for example, a mechanical relay or a semiconductor relay, and are configured to be able to cut off the electric power from the battery BT.

The inverter circuit 14a is a FET bridge circuit composed of semiconductor switching elements (FETs) corresponding to each of the three-phase windings (Ua, Va, Wa) 15a of the electric motor 15. Similarly, the inverter circuit 14b is a FET bridge circuit composed of semiconductor switching elements (FETs) corresponding to each of the three-phase windings (Ub, Vb, Wb) 15b of the electric motor 15.

These switching elements (FETs) are also called power elements, and for example, semiconductor switching elements such as MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) and IGBT (Insulated Gate Bipolar Transistor) are used.

One end of the ignition switch (IG-SW) 31 is connected to the battery BT, and the other end is connected to the IG voltage detection unit 37a provided in the motor control device 1a and the IG voltage detection unit 37b provided in the motor control device 1b. It is connected. The IG voltage detection units 37a and 37b perform AD conversion of the ignition (IG) voltage value and input the ignition (IG) voltage value as a digital IG voltage value to each of the CPUs 12a and 12b.

In the motor control devices 1a and 1b, the CPUs 12a and 12b are configured to enable real-time mutual communication. Further, the motor control devices 1a and 1b are connected to other control units (CAN communication buses) 27H and 27L via a CAN signal line (CAN communication bus) 27H and 27L connected to an in-vehicle network (CAN) that exchanges various information of vehicles equipped with them. Data communication is performed with the ECU) by the CAN protocol.

The CAN signal lines 27H and 27L each consist of CAN-H line 27Ha and CAN-L line 27La constituting the first system, and CAN-H line 27Hb and CAN-L line 27Lb constituting the second system, respectively. It is a linear communication line.

The electric motor 15 is equipped with rotation angle sensors 11a and 11b that detect the rotation position of the rotor of the motor corresponding to the three-phase windings 15a and 15b, respectively. The output signal from the rotation angle sensor 11a (the angle signal of the rotation shaft of the electric motor 15) is transmitted to the CPU 12a, and the output signal from the rotation angle sensor 11b is transmitted to the CPU 12b. Further, vehicle speed signals are transmitted from the vehicle speed sensors 10a and 10b to the CPUs 12a and 12b, respectively.

The CPUs 12a and 12b calculate the motor rotation speed based on the rotation angle signals from the rotation angle sensors 11a and 11b, respectively. As the rotation angle sensors 11a and 11b, for example, a resolver, an MR sensor, an encoder, or the like is used.

Next, the operation of the motor control device according to the present embodiment having the above configuration and the motor control process when an internal reset occurs in one system will be described.

FIG. 2 is a flowchart showing a processing procedure in the control units (CPU) 12a and 12b of the motor control devices 1a and 1b. Further, FIG. 3 shows an example of the range and control mode of the battery voltage in the motor control devices 1a and 1b.

In the motor control device according to the present embodiment, as shown in FIG. 3, the battery voltage range is classified into five threshold values, and the voltage value (threshold value) of "Normal" means that the motor control (for example, for example) is always performed. This is the power supply voltage value at which assist control) is performed.

When the threshold value is "High", which has a higher voltage value than "Normal", or "Low", which has a lower voltage value than "Normal", the control mode is "degenerate". This is, for example, a control mode (for example, stop of assist control) in which the maximum value of the output is lowered over a certain period of time when the output at the time of "Normal" is 100%.

On the other hand, when the threshold value is "Over", which has a higher voltage value than "High", or "Under", which has a lower voltage value than "Low", the control mode shifts to "control discontinuation".

From the above, the battery voltage range of “High” to “Low” indicated by the arrow in FIG. 3 is the operation guarantee range in the motor control device (assist guarantee in the case of the electric power steering device).

The motor control devices 1a and 1b monitor the communication status between the control units (CPU) 12a and 12b (for example, presence / absence of communication, abnormality of communication data, failure of other system, etc.) in a communication status monitoring unit (not shown). ing. Therefore, in the first step S11 of FIG. 2, it is determined whether or not the communication between the CPUs (real-time mutual communication) by the CPUs 12a and 12b is normally performed based on the monitoring result by the communication status monitoring unit. ..

In communication between multiple systems, CPU-to-CPU communication is performed redundantly between the systems (for example, UART (Universal Asynchronous Receiver Transmitter) communication, which is asynchronous serial communication, and signals are sent periodically to operate normally. WD (Watch Dog) communication to monitor whether or not the signal is received normally. When all the receptions do not arrive for the specified time, it is determined that the CPU of the other system has failed and the CPU has stopped operating.

When it is determined in step S11 that the inter-CPU communication is interrupted, in step S13, it is determined whether or not the motor control device is cranking or not cranking. This is a process of determining whether or not the cause of the interruption of CPU-to-CPU communication is due to cranking.

Whether the motor control device is cranking or not is determined by, for example, an idle stop (IS) in which the engine of the vehicle equipped with the motor control device is temporarily stopped at the time of starting or while the vehicle is stopped. ) Is released. Here, whether or not the engine is started is determined by whether or not the period from when the CPU is started by turning on the IG-SW (ignition switch) 31 to start the predetermined start sequence and the initial diagnosis is completed is within the predetermined time. Judgment based on.

When assist control is performed by the motor control device, cranking occurs after the ignition is turned on, and when the engine speed reaches a constant value, the motor control device shifts to a state in which assist can be started.

Whether or not it is at the time of release from the idle stop (at the time of return) is determined, for example, based on the information received via the CAN signal line (CAN communication bus) 27H, 27L, the rotation angle sensor 11a of the engine. , 11b There is a method of determining based on the engine speed detected from the output and the vehicle speed detected by the vehicle speed sensors 10a and 10b.

When it is determined in step S13 that the motor control device is cranking, the voltage value of the battery BT detected by the BT voltage detection units 20a and 20b in step S15 is a specified threshold value (“Under” in FIG. 3). Judge whether or not it is as follows. For example, when the battery voltage value of 12V is usually lowered to 7V or less, it is determined that the battery voltage value is a low voltage of a specified threshold value (Under) or less.

When the motor control devices 1a and 1b are motor control devices for electric power steering, a voltage below the above specified threshold is defined as a low voltage (voltage below the guaranteed voltage) outside the guaranteed operation range of the electric power steering (EPS). Will be done.

In step S17, it is determined whether or not a CPU reset has occurred in the other system. The CPU reset is, for example, in _{the case of a CPU having a reference operating voltage VCC} of 5 V, a low voltage detection unit (LVI) that is a low voltage detection unit in the CPU and has a function of detecting that the operating voltage has become low. When the operating voltage is determined to be 4.5V, which is lower than the reference value, a reset signal is given to the CPU from the internal reset circuit of the CPU, and a low voltage reset occurs in the system under the control of the CPU.

For example, when the own system (A system) determines that a CPU reset has occurred in the other system (B system), it means that a voltage drop has occurred in the B system to the extent that communication between CPUs becomes impossible.

_{When the core voltage VDD} of the CPUs 12a and 12b is lowered to a value (for example, 1.3V) smaller than the normal operating voltage threshold (for example, 5V), the low voltage operating voltage is the CPU core voltage _VDD. If the voltage does not fall below, the CPU can determine the low voltage.

As described above, the control units (CPUs) 12a and 12b of the motor control device determine whether or not communication between CPUs is interrupted, whether or not the voltage value of the battery BT is below the specified threshold value, and whether or not a CPU reset has occurred. Judgment is made in an integrated manner, and based on the results, it is determined whether or not the cause of these events is cranking.

Therefore, when the communication between CPUs is interrupted, the voltage value of the battery BT is equal to or less than the specified threshold value, and the CPU reset occurs, for example, the A system is caused by the occurrence of cranking in the B system which is the partner system. It can be judged that the event occurred in. On the other hand, even if the voltage value of the battery BT is equal to or less than the specified threshold value, if the inter-CPU communication is normally performed after the CPU reset, the other CPU is operating normally. The occurrence of cranking is denied.

When it is determined in step S18 that cranking has occurred, since the vehicle equipped with the motor control device is stopped, the electric motors are driven by both the A and B systems after a while to obtain the output torque. be able to. If no cranking has occurred, the vehicle is running and the vehicle shifts to fail operation.

When the communication between the CPUs is interrupted in this way, the voltage value of the battery BT becomes equal to or less than the specified threshold value, and the CPU reset occurs, the own system puts the transition to the fail operation described later in the standby state in step S19. To do. Then, in step S21, the above-mentioned standby state is continued until the specified condition is satisfied.

Here, the CPU-to-CPU communication is tried at regular intervals even while the standby state is continued. As a result, it is possible to quickly confirm whether or not the inter-CPU communication has been reestablished. At this time, the safety of the motor control can be ensured by waiting in consideration of the rotation speed of the electric motor 15.

The above-mentioned specified condition means, for example, a state in which the voltage value of the battery becomes equal to or higher than a predetermined threshold value continues for a specified time, or until a predetermined initial diagnosis execution condition in the control unit (CPU) is satisfied. The specified time corresponds to a predetermined initial diagnosis period by the CPU. In this way, by setting a specified time or a specified condition so that the standby state is not unlimited, safe and quick motor control becomes possible.

The period of a predetermined initial diagnosis is, for example, several hundred milliseconds to several seconds. Further, the conditions for carrying out the initial diagnosis include that the motor rotation speed is below a certain level and that the voltage of the drive unit is above a specified value. The above-mentioned specified conditions include both, or one of, the above-mentioned state in which the voltage value of the battery is equal to or higher than the predetermined threshold value for a specified time, and the above-mentioned conditions for carrying out the initial diagnosis.

The predetermined threshold value of the battery voltage under the above-mentioned specified conditions is not more than the voltage value in the assist operation guarantee range, for example, 6.5 V or less that makes the assist 0%.

When the rotation speed of the electric motor 15 is equal to or higher than the predetermined rotation speed, the specified time may not be counted. Further, when the supply voltage to the electric motor 15 is equal to or less than a predetermined voltage, the specified time may not be counted.

If it is determined in step S21 that the above-mentioned specified conditions are satisfied, in the following step S23, the system in which the low voltage is generated restarts its own system by the low voltage detection unit (LVI). Then, when the own system is restarted, if the other system is in the assist permitted state and has not shifted to the fail operation described later, in step S25, the own system undergoes the initial diagnosis and drives and controls the electric motor 15. Shift to steering assist permission.

By doing so, the system in which the internal reset has occurred can be safely and reliably restored, and normal motor drive operation (for example, assist control) can be resumed in both the system A and the system B.

The motor control device performs a plurality of initial diagnoses as a system during the initial diagnosis period, but by accumulating the worst time for completing the initial diagnosis and defining the time required for the diagnosis in the own system, the start-up time ( For example, about 1 to 2 seconds). Further, regarding the initial diagnosis at the time of startup, it is possible to determine whether the system is restarted by turning on the IG-SW (ignition switch) or restarted by CPU reset.

Therefore, it is conceivable to perform the initial diagnosis uniformly in consideration of the safety in control without considering the mode of restart, but the initial diagnosis may not be performed when the system is restarted by reset. This makes it possible to shorten the time required for restarting.

On the other hand, in the initial diagnosis, the control system in which the internal reset has occurred may be sequentially confirmed whether or not it is safe to start the drive unit and the like. Further, it may be confirmed whether or not the stop portion (for example, a relay or the like) of the safety mechanism functions.

In the initial diagnosis process, in order to drive the system safely, it is judged whether or not the drive circuit, the relay, and the like have a failure treatment function in order for each part. When the normality of all parts is confirmed in the initial diagnosis, energization is started.

In the motor control devices 1a and 1b, the fail operation state of the partner system is shared by the inter-CPU communication. Therefore, if the other system has shifted to fail operation when restarting, for example, it is judged that a reset has occurred due to some abnormality in the own system, there is a problem with the startup method, etc., and it is normal. You may not move to control.

In step S23, if the above-mentioned specified time continues, or even if the specified conditions are satisfied, the system in which the internal reset has occurred does not restart, the process proceeds to a predetermined fail operation (step S27). In this way, in addition to the continuation of the specified time or the establishment of the specified conditions, it is possible to reliably shift to normal startup by determining whether or not there is a restart in the reset system.

In the motor control device, if communication between CPUs is interrupted but not during cranking, or if the voltage value of the battery BT is equal to or higher than the specified threshold even during cranking, or the voltage value of the battery BT is the specified threshold. If the CPU reset has not occurred even in the following cases, it is determined that the system is abnormal, and the process proceeds to the fail operation in step S27.

If it is known that the inter-CPU communication is restored and the partner system is activated before the continuation of the specified time described above is completed (before the specified time elapses), the normal control is started. On the other hand, when the inter-CPU communication is restored after the specified time has elapsed (when the operation is started later than the specified time), the other system has shifted to the fail operation. Therefore, in the own system, the motor starts from the initial diagnosis state. It does not shift to the control state (assist state).

In the fail operation, for example, a process of compensating for a decrease in the output of the electric motor in a system determined to be abnormal is performed with a normal system. As a result, even if one system fails, it is possible to approach the control at the normal time as much as possible by the normal system. That is, the abnormality of the other system can be regarded as a failure of one system, and the motor drive can be continued only in the normal system.

Since the motor control devices 1a and 1b according to the present embodiment have a redundant configuration having a plurality of systems (system A and system B), even if a failure or the like occurs in one of these two systems, it is normal. By driving the electric motor with one system of, for example, it is possible to continue driving the motor with an output torque of at least 50% when the two systems are normal.

FIG. 4 is a schematic configuration of an electric power steering device equipped with the motor control device according to the present embodiment. The electric power steering device 10 of FIG. 4 includes motor control devices 1a and 1b as electronic control units (ECUs), a steering handle 2 which is a steering member, a rotating shaft 3 connected to the steering handle 2, and a pinion gear. 6. The rack shaft 7 and the like are provided.

The rotating shaft 3 meshes with a pinion gear 6 provided at its tip. The pinion gear 6 converts the rotational motion of the rotating shaft 3 into a linear motion of the rack shaft 7, and a pair of wheels 5a, 5b provided at both ends of the rack shaft 7 at an angle corresponding to the amount of displacement of the rack shaft 7. Is steered.

The rotating shaft 3 is provided with torque sensors 9a and 9b for detecting the steering torque when the steering handle 2 is operated, and the detected steering torque is sent to the motor control devices 1a and 1b. The motor control devices 1a and 1b generate motor drive signals based on signals such as steering torque acquired from torque sensors 9a and 9b and vehicle speed from vehicle speed sensors 10a and 10b, and output the signals to the electric motor 15.

An auxiliary torque for assisting the steering of the steering handle 2 is output from the electric motor 15 to which the motor drive signal is input, and the auxiliary torque is transmitted to the rotating shaft 3 via the reduction gear 4. As a result, the torque generated by the electric motor 15 assists the rotation of the rotating shaft 3, thereby assisting the driver in operating the steering wheel.

Therefore, in the electric power steering device equipped with the motor control device according to the present embodiment, even if the battery voltage drops due to cranking, the normal motor drive operation is resumed in both of the plurality of control systems, and the steering assist is continued. Is possible.

As described above, the motor control device according to the present embodiment determines whether or not the cause of the abnormality in the communication between the plurality of control systems (CPUs) is due to cranking, thereby controlling the abnormality (to fail operation). It is possible to determine whether migration) is necessary.

That is, when there is a battery voltage drop and communication between CPUs is interrupted, it is a battery voltage drop due to cranking, and when an internal reset occurs in one of the plurality of control systems, the other control system has a battery voltage. When one of the control systems recovers from a low battery voltage by continuing the state where the value is equal to or higher than the predetermined threshold for a specified time or shifting to the standby state until the specified conditions are satisfied, both of the multiple control systems Normal motor drive operation can be resumed.

Therefore, when there is a battery voltage drop in the remote control system and communication between CPUs is interrupted, if it is determined that it is due to cranking, whether or not the recognition value of the battery voltage of the own control system is below the specified threshold value. Based on this, it is possible to accurately determine whether one system is normal or abnormal.

Furthermore, based on the fact that the voltage of the batteries supplied to multiple control systems has dropped, an internal reset has occurred in one system, and communication between control units (communication between CPUs) has been interrupted, it is easy and reliable. Can diagnose system failure.

1a, 1b Motor control device 2 Steering handle 3 Rotating shaft 4 Reduction gear 6 Pinion gear 7 Rack shaft 9a, 9b Torque sensor 10 Electric power steering system 10a, 10b Vehicle speed sensor 11a, 11b Rotation angle sensor 12a, 12b Control unit (CPU)
13a, 13b Inverter control unit 14a, 14b Inverter circuit 15 Electric motor 15a, 15b Three-phase winding 16a, 16b Filter 17a, 17b Power relay 19a, 19b CANI / F
20a, 20b BT voltage detection unit 21a, 21b Power supply control unit 27H, 27L CAN signal line 27Ha, 27Hb CAN-H line 27La, 27Lb CAN-L line 31 Ignition switch (IG-SW)
33a, 33b Low voltage detector (LVI)
35a, 35b Internal reset circuit 37a, 37b IG voltage detector BT battery

Claims (19)

A motor control device that receives power from a battery and is composed of a plurality of control systems and drives an electric motor by a control unit provided for each of the plurality of control systems.
A battery voltage detector that detects the voltage value of the battery,
A drive voltage detection unit that detects the drive voltage value of the control unit,
A reset unit that internally resets the control unit based on the detection result of the drive voltage detection unit,
A communication status monitoring unit that monitors the presence or absence of communication between the control units,
With
When the internal reset occurs in one of the plurality of control systems and the communication status monitoring unit determines that the control units are in a communication blackout state, the other system of the plurality of control systems is predetermined. A motor control device that puts the transition to the fail operation into a standby state and restarts the drive control of the electric motor after the specified conditions are satisfied. The motor control according to claim 1, wherein the control system in which the internal reset has occurred performs a predetermined initial diagnosis after restarting the control system when the voltage value of the battery returns to a predetermined operation guaranteed voltage range. apparatus. The specified condition is the predetermined initial diagnosis execution condition in the control unit, or a state in which the voltage value of the battery becomes equal to or higher than the predetermined threshold value when the voltage value of the battery is detected to be equal to or lower than the predetermined threshold value by the battery voltage detection unit. The motor control device according to claim 2, wherein the motor control device is to continue for a specified time. The motor control device according to claim 3, wherein the specified time corresponds to a period required for the predetermined initial diagnosis by the control unit. The motor control device according to claim 1, wherein the control system restarted by the internal reset does not perform a predetermined initial diagnosis. The first aspect of claim 1, wherein when the one system is restarted by the internal reset, if the other system shifts to the predetermined fail operation, the one system does not shift to the drive control of the electric motor. Motor control device. Further provided with means for calculating the motor rotation speed based on the output from the rotation angle sensor that detects the angle of the rotation axis of the electric motor.
The motor control device according to claim 3, wherein the specified time is not counted when the rotation speed is equal to or higher than a predetermined rotation speed. Further provided with means for detecting the supply voltage to the electric motor,
The motor control device according to claim 3, wherein when the supply voltage is equal to or lower than a predetermined voltage, the specified time is not counted. The motor control device according to claim 1, wherein communication between the control units is tried even during the standby state. The motor control device according to claim 1, further comprising means for determining whether or not the interruption of communication between the control units is caused by restarting the engine by cranking. When it is determined by the cranking that the communication between the control units is interrupted, it is determined whether or not there is an abnormality in the control system based on the determination result of whether or not the voltage value of the battery in the other system is equal to or less than a predetermined threshold value. 10. The motor control device according to claim 10. The motor control device according to claim 11, wherein when the other system is determined to be abnormal, the process shifts to the predetermined fail operation corresponding to the abnormal state. The motor control device according to claim 12, wherein if the control system in which the internal reset has occurred does not restart even if the specified conditions are satisfied, the motor control device shifts to the predetermined fail operation. When it is determined that the interruption of communication between the control units is not caused by restarting the engine due to cranking, the one system shifts to the predetermined fail operation even if the internal reset occurs due to the voltage drop of the battery. 10. The motor control device according to claim 10. The motor control device according to any one of claims 1 to 14, wherein the predetermined fail operation is a process of supplementing the output decrease of the electric motor in the control system determined to be abnormal with the normal control system. The motor control device according to any one of claims 1 to 15, which is mounted on a vehicle for in-vehicle use. An electric power steering system including the motor control device according to any one of claims 1 to 16. It is a method for diagnosing one-system failure in a motor control device that receives power from a battery and is composed of a plurality of control systems and drives an electric motor by a control unit provided for each of the plurality of control systems.
The process of detecting the voltage value of the battery and
The process of detecting the drive voltage value of the control unit and
A process of internally resetting the control unit based on the detection result of the drive voltage value, and
The process of monitoring the presence or absence of communication between the control units and
In the battery voltage detection process, the battery voltage value is detected to be equal to or lower than a predetermined threshold value, the internal reset occurs in one of the plurality of control systems, and communication is interrupted between the control units in the communication monitoring process. When it is determined that the condition is present, the step of diagnosing that a failure has occurred in the one system and
A method for diagnosing one-sided failure. A determination process for determining whether or not the interruption of communication between the control units is caused by restarting the engine due to cranking, and
When it is determined by the cranking that the communication between the control units is interrupted in the determination step, the control system is abnormal based on the determination result of whether or not the voltage value of the battery in the other system is equal to or less than a predetermined threshold value. And the process of determining the presence or absence of
18. The method for diagnosing a single system failure according to claim 18.

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