WO2022059615A1 - 電子制御装置 - Google Patents
電子制御装置 Download PDFInfo
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- WO2022059615A1 WO2022059615A1 PCT/JP2021/033308 JP2021033308W WO2022059615A1 WO 2022059615 A1 WO2022059615 A1 WO 2022059615A1 JP 2021033308 W JP2021033308 W JP 2021033308W WO 2022059615 A1 WO2022059615 A1 WO 2022059615A1
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- Prior art keywords
- current
- microcomputer
- detection circuit
- negative electrode
- current detection
- Prior art date
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- 238000001514 detection method Methods 0.000 claims description 109
- 230000005856 abnormality Effects 0.000 claims description 54
- 238000004804 winding Methods 0.000 claims description 27
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- 239000004065 semiconductor Substances 0.000 description 4
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/16—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
- H02P25/22—Multiple windings; Windings for more than three phases
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/024—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02P29/028—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load the motor continuing operation despite the fault condition, e.g. eliminating, compensating for or remedying the fault
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/60—Controlling or determining the temperature of the motor or of the drive
- H02P29/68—Controlling or determining the temperature of the motor or of the drive based on the temperature of a drive component or a semiconductor component
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/046—Controlling the motor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/04—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear
- B62D5/0457—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such
- B62D5/0481—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures
- B62D5/0496—Power-assisted or power-driven steering electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear characterised by control features of the drive means as such monitoring the steering system, e.g. failures by using a temperature sensor
Definitions
- the present invention relates to an electronic control device that independently controls energization for each system in an in-vehicle system redundantly configured in a plurality of systems.
- the electronic control unit limits the energization control of the abnormal system when an abnormality occurs in some systems by independently performing energization control for each system in the in-vehicle system redundantly configured in multiple systems. It is known that the normal system continues the energization control.
- an EPS Electric Power Steering
- an EPS Electric Power Steering system provided with two systems for controlling energization for each winding set for a motor having two independent winding sets.
- a control system ground common to the two systems is provided in order to avoid a relative fluctuation of the ground potential of the control system between the systems and a cost increase due to the adoption of the differential signal method. Therefore, when a resistance value increase abnormality such as an open failure occurs in the ground harness of one system, current flows from one system to the other system via the control system ground, and an excessive current flows into the ground harness of the other system. Will flow. Therefore, the current flowing in the control system ground is detected, and the current of the motor is limited when the resistance value increase abnormality of the ground harness is detected based on this current.
- the present invention prolongs the time until the system function of a part of the in-vehicle system redundantly configured in a plurality of systems is restricted due to an abnormality of the system as much as possible. It is an object of the present invention to provide an electronic control device.
- the first positive electrode connector and the first negative electrode connector connected to the first power source, the second positive electrode connector and the second negative electrode connector connected to the second power source, the first positive electrode connector and the like.
- a first inverter connected to the first negative electrode connector and energized to drive the first winding set of the electric motor, and connected to the second positive electrode connector and the second negative electrode connector to energize the second winding set of the electric motor. Between the first negative electrode connector and the ground portion connected to the first negative electrode connector and the second negative electrode connector, the first negative electrode connector and the ground portion, or between the second negative electrode connector and the ground portion.
- a current detection circuit that can detect the current flowing through the ground section between the first negative electrode connector and the second negative electrode connector based on the sensor section provided in the sensor section and the output signal of the sensor section, and a microcomputer. Then, it is connected to the first positive electrode connector and the first negative electrode connector to control the output of the first inverter, and is connected to the second positive electrode connector and the second negative electrode connector to control the output of the second inverter. It has a second microcomputer, and the first microcomputer and the second microcomputer estimate the rising temperature inside the electronic controller based on the output voltage of the current detection circuit, and the first microcomputer reaches the rising temperature. It comprises a microcomputer that initiates a limitation of the current output from the first inverter based on, or a second microcomputer initiates a limitation of the current output from the second inverter based on the rising temperature.
- the electronic control device in an in-vehicle system redundantly configured in a plurality of systems, it is possible to prolong the time until the system function of a part of the systems is restricted due to an abnormality of the system as much as possible. can.
- FIG. 1 shows an example of an electric steering system according to the first embodiment.
- the electric steering system 100 functions as a power steering assisting the steering torque when the pair of steering wheels 1002 are steered by the steering torque of the steering wheel 1001 in the normal operation of the vehicle 1000 in which the driver operates the steering. ..
- the steering torque generated by the operation of the steering wheel 1001 is transmitted to the pinion gear 1005 connected to the pinion shaft 1004 via the steering shaft 1003 and the like.
- the rotational motion of the pinion gear 1005 due to the transmitted steering torque is converted into a linear motion in the vehicle width direction by the rack gear 1006 that meshes with the pinion gear 1005, and this linear motion activates a pair of steering mechanisms 1007 connected to the rack gear 1006. do.
- the steering wheels 1002 connected to the pair of steering mechanisms 1007 are steered, but in power steering, an assist torque that assists the steering torque is applied to the transmission path of the steering torque to the pair of steering mechanisms 1007. It is configured to add.
- the electric steering system 100 includes a motor 1 and an electric steering control device (hereinafter, simply referred to as “ECU”) 2 that has a built-in computer to control the drive of the motor 1. Further, the electric steering system 100 includes a steering angle sensor 3, a steering torque sensor 4, and a speed reducer 5 that reduces the output of the motor 1 and transmits it to the steering shaft 1003 in the steering column 1008 including the steering shaft 1003. ..
- ECU electric steering control device
- the ECU 2 is configured to input various signals such as a steering angle detection signal SA from the steering angle sensor 3, a steering torque detection signal ST from the steering torque sensor 4, and a vehicle speed detection signal SV from the vehicle speed sensor 6. Further, the ECU 2 calculates a target value (target torque) of the assist torque based on the steering angle, steering torque, vehicle speed, etc. obtained from various input signals so that the torque generated by the motor 1 approaches the target torque. , Controls the rotational drive of the motor 1. Then, the torque generated by the motor 1 is transmitted to the steering shaft 1003 via the speed reducer 5, thereby assisting the steering force with the assist torque according to the operating state of the vehicle 1000.
- a target value target torque
- the electric steering system 100 functions as an automatic steering device in the automatic driving of the vehicle 1000, and further includes an outside world recognition device 8 and an automatic driving controller 9 in order to exert such a function.
- the outside world recognition device 8 is, for example, a camera or the like, and is configured to acquire outside world information or the like of the vehicle 1000.
- the automatic driving controller 9 is configured to output an automatic driving request signal Sauto when the vehicle 1000 is automatically driven. Further, the automatic operation controller 9 calculates the target steering angle of the steering wheel 1001 based on the outside world information acquired by the outside world recognition device 8, and outputs the steering angle command signal SA * including the target steering angle information. It is composed.
- the ECU 2 controls the rotational drive of the motor 1 so that the current steering angle acquired from the steering angle detection signal SA approaches the target steering angle acquired from the steering angle command signal SA *. do.
- the torque generated by the motor 1 is transmitted to the steering shaft 1003 via the speed reducer 5, whereby the vehicle 1000 is automatically driven.
- the electric steering system 100 includes an electric system in which power is supplied from the first vehicle-mounted battery (external power supply) 7A to the motor 1 via the ECU 2, and a power supply from the second vehicle-mounted battery (external power supply) 7B to the motor 1 via the ECU 2.
- the electrical system to which is supplied and the two systems are made redundant. As a result, even if an abnormality occurs in one electric system, the power supply to the motor 1 is continued in the other electric system to maintain the function of the electric steering system 100.
- the electric system to which power is supplied from the first in-vehicle battery 7A is referred to as a "first electric system", and "A" is included in the reference code attached to the component of the first electric system.
- the electric system to which power is supplied from the second in-vehicle battery 7B is referred to as a "second electric system", and "B" is used as a reference code attached to a component of the second electric system.
- FIG. 2 shows an example of the internal configuration of the ECU 2 in the electric steering system 100.
- the configuration used for the normal operation (non-automatic operation) of the vehicle 1000 is extracted and shown from the ECU 2 in the electric steering system 100 of FIG.
- the first inverter 11A and the first inverter 11A for driving the first winding set which will be described later, among the windings of the motor 1 as the first electric system powered by the first vehicle-mounted battery 7A.
- a first control circuit 12A that controls the output of the inverter is accommodated.
- a second inverter 11B and a second inverter 11B for driving a second winding set which will be described later, among the windings of the motor 1 as a second electric system powered by the second vehicle-mounted battery 7B.
- a second control circuit 12B that controls the output of the inverter 11B is accommodated.
- the first control circuit 12A and the second control circuit 12B share a ground by the control system common ground 13 in the ECU 2.
- a first positive electrode connector 14A and a first negative electrode connector 15A are provided in the first electric system, and a second positive electrode connector 14B and a second positive electrode connector 14B are provided in the second electric system.
- a negative electrode connector 15B is provided.
- the first positive electrode connector 14A is electrically connected to the positive electrode of the first vehicle-mounted battery 7A via the first power supply positive electrode line 61A, and the first negative electrode connector 15A is connected to the first vehicle-mounted battery via the first power supply negative electrode line 62A. It is electrically connected to the negative electrode of 7A.
- the second positive electrode connector 14B is electrically connected to the positive electrode of the second vehicle-mounted battery 7B via the second power supply positive electrode line 61B, and the second negative electrode connector 15B is connected to the second vehicle-mounted battery via the second power supply negative electrode line 62B. It is electrically connected to the negative electrode of 7B.
- the two negative electrodes of the first vehicle-mounted battery 7A and the second vehicle-mounted battery 7B are electrically connected to the body ground of the vehicle 1000, respectively.
- the configuration including the first negative electrode connector 15A and the first power supply negative electrode line 62A is referred to as a first ground (GND) harness HA
- the configuration including the second negative electrode connector 15B and the second power supply negative electrode line 62B is referred to as a second ground (GND) harness HA.
- GND Harness HB.
- the first positive electrode connector 14A is electrically connected to the positive electrode side bus of the first inverter 11A via the first positive electrode line 16A inside the housing 10 of the ECU 2.
- the first branch positive electrode line 17A branched from the first positive electrode line 16A is electrically connected to a power supply circuit described later in the first control circuit 12A.
- the first branch positive electrode line 17A may branch from the first positive electrode line 16A inside the first positive electrode connector 14A.
- the second positive electrode connector 14B is electrically connected to the positive electrode side bus of the second inverter 11B via the second positive electrode line 16B inside the housing 10 of the ECU 2.
- the second branched positive electrode line 17B branched from the second positive electrode line 16B is electrically connected to a power supply circuit described later in the second control circuit 12B.
- the second branch positive electrode line 17B may be branched from the second positive electrode line 16B inside the second positive electrode connector 14B.
- the first negative electrode connector 15A is electrically connected to the negative electrode side bus of the first inverter 11A via the first negative electrode line 18A inside the housing 10 of the ECU 2.
- the first branch negative electrode line 19A branched from the first negative electrode line 18A is electrically connected to the control system common ground 13.
- the negative electrode side bus of the first inverter 11A and the control system common ground 13 are electrically connected to the negative electrode of the first vehicle-mounted battery 7A via the first GND harness HA.
- the first branch negative electrode line 19A may be branched from the first negative electrode line 18A inside the first negative electrode connector 15A.
- the second negative electrode connector 15B is electrically connected to the negative electrode side bus of the second inverter 11B via the second negative electrode line 18B inside the housing 10 of the ECU 2.
- the second branched negative electrode line 19B branched from the second negative electrode line 18B is electrically connected to the control system common ground 13.
- the negative electrode side bus of the second inverter 11B and the control system common ground 13 are electrically connected to the negative electrode of the second vehicle-mounted battery 7B via the second GND harness HB.
- the second branch negative electrode line 19B may be branched from the second negative electrode line 18 inside the second negative electrode connector 15B.
- a first power supply relay 20A composed of a semiconductor element such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is located on the first inverter 11A side of the first positive electrode line 16A from the branch point of the first branch positive electrode line 17A. Be placed.
- the first power supply relay 20A operates on and off according to a control signal input from the outside, power is supplied from the first vehicle-mounted battery 7A to the first inverter 11A when it is on, and the first is when it is off. The power supply from the vehicle-mounted battery 7A to the first inverter 11A is cut off.
- a second power supply relay 20B similar to the first power supply relay 20A is arranged on the second inverter 11B side of the second positive electrode line 16B from the branch point of the second branch positive electrode line 17B.
- the second power supply relay 20B operates on and off according to a control signal input from the outside, power is supplied from the second vehicle-mounted battery 7B to the second inverter 11B when it is on, and the second is when it is off. The power supply from the vehicle-mounted battery 7B to the second inverter 11B is cut off.
- first negative electrode line 18A On the first inverter 11A side of the branch point of the first branch negative electrode line 19A, a first for detecting the phase current flowing in the first winding set described later in the winding of the motor 1.
- Shunt resistor 21A is arranged.
- second negative electrode line 18B On the second inverter 11B side of the branch point of the second branch negative electrode line 19B, a second for detecting the phase current flowing in the second winding set described later in the winding of the motor 1. 2
- the shunt resistor 21B is arranged.
- first branch negative electrode line 19A a first current-voltage conversion for detecting the current flowing through it, that is, the current flowing between the two electric systems via the control system common ground (hereinafter referred to as “common ground current”).
- common ground current the current flowing between the two electric systems via the control system common ground (hereinafter referred to as “common ground current”).
- the element 22A is arranged.
- the first current-voltage conversion element 22A is composed of a resistor R1A and a capacitor CA connected in parallel
- the second current-voltage conversion element 22B is a resistor R1B and a capacitor C1B connected in parallel. Consists of.
- the resistors R1A and R1B correspond to a sensor unit that converts the detected current into a voltage.
- the capacitors CA and CB suppress the generation of a transient potential difference between the negative electrode side of the corresponding inverters 11A and 11B and the control system common ground 13, respectively, and may be provided as necessary. For convenience of explanation, it is assumed that the resistors R1A and R1B have the same resistance value.
- the first control circuit 12A controls the output of the first inverter 11A, and is the first power supply circuit 23A, the first microcomputer (hereinafter referred to as “first microcomputer”) 24A, the first drive circuit 25A, and the first.
- a current detection circuit 26A or the like is provided.
- the second control circuit 12B controls the output of the second inverter 11B, and is a second power supply circuit 23B, a second microcomputer (hereinafter referred to as “second microcomputer”) 24B, and a second drive circuit 25B, second. It is provided with a current detection circuit 26B and the like.
- the power supply circuits 23A and 23B, the microcomputers 24A and 24B, and the drive circuits 25A and 25B are connected to the control system common ground 13, respectively.
- the first power supply circuit 23A is electrically connected to the first branch positive electrode line 17A and the power supply voltage of the first vehicle-mounted battery 7A is applied to generate a first internal power supply voltage VA of, for example, 5 volts.
- the first internal power supply voltage VA is supplied to the first microcomputer 24A, the first drive circuit 25A, and the first current detection circuit 26A.
- a diode DA is arranged in the first branch positive electrode line 17A in order to suppress backflow from the first power supply circuit 23A to the first positive electrode connector 14A.
- the second power supply circuit 23B is electrically connected to the second branch positive electrode line 17B and the power supply voltage of the second vehicle-mounted battery 7B is applied to generate a second internal power supply voltage VB of, for example, 5 volts.
- the second internal power supply voltage VB is supplied to the second microcomputer 24B, the second drive circuit 25B, and the second current detection circuit 26B.
- a diode DB is arranged in the second branch positive electrode line 17B in order to suppress backflow from the second power supply circuit 23B to the second positive electrode connector 14B.
- the microcomputers 24A and 24B each have a processor such as a CPU (Central Processing Unit), a non-volatile memory such as a ROM (Read Only Memory), a volatile memory such as a RAM (Random Access Memory), an input / output interface, and the like. ing.
- the microcomputers 24A and 24B are configured to be communicable via the communication line 27.
- the microcomputers 24A and 24B calculate the target torque as described above, and based on this target torque, calculate the target current value which is the target value of the energization amount (for example, q-axis current) of the motor 1.
- the microcomputers 24A and 24B calculate the target current value for each system in each electric system based on the target current value and the predetermined output ratio (for example, 50%: 50%) of the inverters 24A and 24B.
- the target current value of the first electric system is referred to as a first target current value
- the target current value of the second electric system is referred to as a second target current value.
- the first microcomputer 24A calculates the energization amount related to the first electric system of the motor 1 based on the detected value of the phase current detected by the first shunt resistor 21A, and this energization amount approaches the first target current value.
- the current is controlled as follows. Specifically, the first microcomputer 24A generates the first inverter control signal based on the difference between the energization amount related to the first electric system and the first target current value by using PI control or the like.
- This first inverter control signal is a signal for controlling the output of the first inverter 11A.
- the second microcomputer 24B calculates the energization amount related to the second electric system of the motor 1 based on the detected value of the phase current detected by the second shunt resistor 21B, and this energization amount approaches the second target current value.
- the current is controlled as follows. Specifically, the second microcomputer 24B generates a second inverter control signal based on the deviation between the energization amount related to the second electric system and the second target current value by using PI control or the like.
- This second inverter control signal is a signal for controlling the output of the second inverter 11B.
- a PWM (Pulse Width Modulation) signal is generated.
- the microcomputers 24A and 24B output the generated inverter control signals from the digital output terminal DO1.
- each of the microcomputers 24A and 24B has a resistance value increase abnormality such as an open failure in the ground harness of the own system based on the output voltage of the current detection circuit of the own system among the current detection circuits 26A and 26B, respectively. Perform an abnormal diagnosis to determine.
- the microcomputers 24A and 24B communicate with each other by the communication line 27, and share at least the information acquired in the abnormality diagnosis of the own system and another system.
- the first drive circuit 25A converts the first inverter control signal output from the digital output terminal DO1 of the first microcomputer 24A into a gate drive signal for driving the switching element of the first inverter 11A and outputs the signal.
- the second drive circuit 25B converts the second inverter control signal output from the digital output terminal DO1 of the second microcomputer 24B into a gate drive signal for driving the switching element of the second inverter 11B and outputs the signal.
- the current detection circuits 26A and 26B diagnose abnormalities of the GND harness HA and HB both when the output of the inverters 11A and 11B is stopped and when the output of the inverters 11A and 11B is stopped, assuming that the power supply voltage is supplied to the microcomputers 24A and 24B. Used for.
- the first current detection circuit 26A has a relatively simple configuration, and a common ground current (current magnitude and direction) is directly used by the first current-voltage conversion element 22A without going through an amplifier circuit or a buffer circuit. It is a circuit to detect.
- the first current detection circuit 26A is composed of an NPN transistor TrA and resistors R2A and R3A.
- the first internal power supply voltage VA is supplied from the first power supply circuit 23A to the collector terminal of the NPN transistor TrA via the resistor R2A.
- the base terminal of the NPN transistor TrA is connected to the digital output terminal DO2 of the first microcomputer 24A.
- the emitter terminal of the NPN transistor TrA is connected to the side opposite to the control system common ground 13 with the resistor R1A in the first branch negative electrode line 19A via the resistor R3A.
- the energization path between the emitter terminal of the NPN transistor TrA and the resistor R3A is connected to the analog input terminal AD of the first microcomputer 24A, and the voltage of the energization path becomes the output voltage EA of the first current detection circuit 26A.
- the second current detection circuit 26B directly uses the second current-voltage conversion element 22B without going through an amplification circuit or a buffer circuit, and has a common ground current (current magnitude and current). It is a circuit that detects the direction).
- the second current detection circuit 26B is composed of an NPN transistor TrB and resistors R2B and R3B.
- the second internal power supply voltage VB is supplied from the second power supply circuit 23B to the collector terminal of the NPN transistor TrB via the resistor R2B.
- the base terminal of the NPN transistor TrB is connected to the digital output terminal DO2 of the second microcomputer 24B.
- the emitter terminal of the NPN transistor TrB is connected to the side opposite to the control system common ground 13 with the resistor R1B in the second branch negative electrode line 19B via the resistor R3B.
- the energization path between the emitter terminal of the NPN transistor TrB and the resistor R3B is connected to the analog input terminal AD of the second microcomputer 24B, and the voltage of the energization path becomes the output voltage EB of the second current detection circuit 26B.
- the NPN transistor TrA is set to the ON state by the control of the first microcomputer 24A, and the second microcomputer 24B is set to the ON state.
- the control sets the NPN transistor TrB to the ON state.
- the NPN transistor TrA is set to the off state by the control of the first microcomputer 24A, and the NPN transistor TrB is set to the off state by the control of the second microcomputer 24B.
- the first microcomputer 24A determines whether or not a resistance value increase abnormality has occurred in the first GND harness HA based on the digital data converted by inputting the output voltage EA of the first current detection circuit 26A to the analog input terminal AD. do. Further, the second microcomputer 24B determines whether or not a resistance value increase abnormality has occurred in the second GND harness HB based on the digital data converted by inputting the output voltage EB of the second current detection circuit 26B to the analog input terminal AD. Is determined.
- FIG. 3 shows an example of the internal configuration of the inverters 11A and 11B in the motor 1 and the ECU 2.
- the motor 1 is a three-phase brushless motor, and includes, for example, a cylindrical stator (not shown) and a rotor R as a permanent magnet rotor rotatably attached to the center of the stator.
- the stator includes two sets of windings independent of each other, the first winding set CA of the first electric system and the second winding set CB of the second electric system.
- the first winding set CA is driven by the first inverter 11A, and consists of a three-phase winding in which a U-phase coil UA, a V-phase coil VA, and a W-phase coil WA are Y-connected.
- the second winding set CB is driven by the second inverter 11B, and is composed of a three-phase winding in which the U-phase coil UB, the V-phase coil VB, and the W-phase coil WB are Y-connected.
- the first winding set CA and the second winding set CB are wound around a stator in a state of being insulated from each other and share a magnetic circuit.
- a U-phase arm, a V-phase arm, and a W-phase arm are provided between the positive electrode side bus LAp connected to the first positive electrode line 16A and the negative electrode side bus LAN connected to the first negative electrode line 18A.
- the U-phase arm is configured by connecting the switching element UAp of the upper arm and the switching element UAn of the lower arm in series.
- the V-phase arm is configured by connecting the switching element VAp of the upper arm and the switching element VAn of the lower arm in series.
- the W-phase arm is configured by connecting the switching element WAp of the upper arm and the switching element WAn of the lower arm in series.
- the two switching elements UAp and UAn of the U-phase arm are connected to the U-phase coil UA
- the two switching elements VAp and VAan of the V-phase arm are connected to the V-phase coil VA
- the two W-phase arms are connected.
- the switching elements WAp and WAn are connected to the W phase coil WA.
- the two switching elements in each phase arm of the first inverter 11A are connected to the coils of the corresponding phases in the first winding set CA of the motor 1 to form a three-phase bridge circuit.
- the U-phase arm, the V-phase arm, and the W-phase are located between the positive electrode side bus LBp connected to the second positive electrode line 16B and the negative electrode side bus LBn connected to the second negative electrode line 18B.
- the arms are connected in parallel.
- the U-phase arm is configured by connecting the switching element UBp of the upper arm and the switching element UBn of the lower arm in series.
- the V-phase arm is configured by connecting the switching element VBp of the upper arm and the switching element VBn of the lower arm in series.
- the W-phase arm is configured by connecting the switching element WBp of the upper arm and the switching element WBn of the lower arm in series.
- the two switching elements UBp and UBn of the U-phase arm are connected to the U-phase coil UB, the two switching elements VBp and VBn of the V-phase arm are connected to the V-phase coil VB, and the two W-phase arms are connected.
- the switching elements WBp and WBn are connected to the W phase coil WB.
- the two switching elements in each phase arm of the second inverter 11B are connected to the coils of the corresponding phases in the second winding set CB of the motor 1 to form a three-phase bridge circuit.
- the switching elements UAp to WBn of the inverters 11A and 11B each have a reverse parallel freewheeling diode and are power control semiconductor elements that can be controlled by the inverter control signals output from the inverters 24A and 24B.
- MOSFETs Metal Oxide Semiconductor Metal Field Effect Transistors
- IGBTs Insulated Gate Bipolar Transistors
- an n-channel MOSFET is used as the switching elements UAp to WBn of the inverters 11A and 11B, and the parasitic diode thereof is used as the freewheeling diode.
- FIG. 4 shows the current path of the ECU 2 during the output of the inverters 11A and 11B in a normal state where the two resistance values of the GND harness HA and HB are both normal, that is, the two resistance values are substantially the same. Since the inverters 11A and 11B are being output, the NPN transistors TrA and TrB of the current detection circuits 26A and 26B are both in the off state.
- the current flows from the positive electrode to the negative electrode of the first vehicle-mounted battery 7A by the following path. That is, the current flowing from the positive electrode to the negative electrode passes through the first power supply positive electrode line 61A, the first positive electrode connector 14A, the first power supply relay 20A, the first inverter 11A, the first shunt resistor 21A, and the first GND harness HA in this order. ..
- the output voltage EA of the first current detection circuit 26A becomes the ground potential or a value close to the ground potential (hereinafter, simply referred to as “ground potential”) V0.
- a relatively large current flows from the positive electrode to the negative electrode of the second vehicle-mounted battery 7B through the following path. That is, the current flowing from the positive electrode to the negative electrode passes through the second power supply positive electrode line 61B, the second positive electrode connector 14B, the second power supply relay 20B, the second inverter 11B, the second shunt resistor 21B, and the second GND harness HB in this order. .. At this time, the output voltage EB of the second current detection circuit 26B becomes the ground potential V0.
- FIG. 5 shows the current path of the ECU 2 during the output of the inverters 11A and 11B in an abnormal state where the resistance value of the first GND harness HA is normal and the resistance value of the second GND harness HB is increasing.
- the current flows from the positive electrode to the negative electrode of the first vehicle-mounted battery 7A in the following path as in the normal state (see the thick solid line arrow). That is, the current flowing from the positive electrode to the negative electrode passes through the first power supply positive electrode line 61A, the first positive electrode connector 14A, the first power supply relay 20A, the first inverter 11A, the first shunt resistor 21A, and the first GND harness HA in this order. .. At this time, the output voltage EA of the first current detection circuit 26A becomes the ground potential V0 as in the normal state.
- the second electric system from the positive electrode of the second vehicle-mounted battery 7B to the second shunt resistor 21B, the second power supply positive electrode line 61B, the second positive electrode connector 14B, the second power supply relay 20B, and the second inverter 11B are in this order.
- the current flows in the same way as in the normal state (see the thick solid line arrow).
- a current flows from the second shunt resistor 21B to the control system common ground 13 via the second branch negative electrode line 19B. This current further flows to the first GND harness HA via the first branch negative electrode line 19A and the first negative electrode line 18A.
- the common ground current flowing from the second electric system to the first electric system also increases.
- the voltage drop in the resistors R1A and R1B increases, so that the output voltage EB of the second current detection circuit 26B rises from the ground potential V0.
- the output voltage EB of the second current detection circuit 26B indirectly indicates the magnitude of the common ground current.
- the output voltage EA of the first current detection circuit 26A is the first. 2
- the output voltage of the current detection circuit 26B rises in the same manner as the output voltage EB. At this time, the output voltage EA of the first current detection circuit 26A indirectly indicates the magnitude of the common ground current.
- the microcomputers 24A and 24B acquire the output voltages EA and EB, and determine whether or not the resistance value increase abnormality has occurred in the GND harness HA and HB based on the acquired output voltages EA and EB. .. That is, when the microcomputers 24A and 24B determine that neither the output voltage EA nor the output voltage EB deviates from the ground potential V 0 (specifically, it is less than the predetermined voltage V th1 ), the GND harness HA and HB It is determined that no resistance increase abnormality has occurred.
- the microcomputers 24A and 24B determine that the output voltage EA deviates from the ground potential V 0 (specifically, the predetermined voltage V th1 or more), they are common to the first electric system and the second electric system. It is determined that the ground current is flowing, and it is determined that the resistance value increase abnormality has occurred in the first GND harness HA. Further, when the microcomputers 24A and 24B determine that the output voltage EB deviates from the ground potential V 0 (specifically, the predetermined voltage V th1 or more), they are common to the first electric system from the second electric system. It is determined that the ground current is flowing, and it is determined that the resistance value increase abnormality has occurred in the second GND harness HB.
- the reception of the output voltage information of the current detection circuit of the other system is awaited. Instead, it may be determined that the resistance value increase abnormality has occurred in the GND harness of the own system.
- FIG. 6 shows the current flowing through the ECU 2 when the abnormal state of FIG. 5 is processed at the time of abnormality.
- the second microcomputer 24B determines in the abnormality diagnosis that a resistance value increase abnormality has occurred in the second GND harness HB
- the second microcomputer 24B limits the current of the inverter output of its own system as an abnormality processing regardless of the set second target current value. Do it.
- the second microcomputer 24B is a component (hereinafter referred to as “low heat resistant component”) of the ECU 2 that may exceed the limit of heat resistance and durability at the earliest stage due to Joule heat generated by energization of resistors R1A and R1B. Determine when to start current limiting for your system based on the rising temperature.
- the low heat resistant parts are resistors R1A and R1B, but the present invention is not limited to these, and microcomputers 24A, 24B and the like may be used.
- the transient rising temperature ⁇ T (t) of the low heat resistant component when time t has elapsed since the common ground current started to flow is used, and the saturation when the temperature rise of the low heat resistant component is saturated is saturated.
- the transient rise temperature ⁇ T (t) is the limit of heat resistance and durability in low heat resistant parts from the saturation rise temperature ⁇ Tc, the heat capacity C [J / K] of the low heat resistant parts and the heat source of the resistor R1A or the resistor R1B. It is expressed by the following equation using the thermal resistance ⁇ [K / W] up to the target portion for determining.
- ⁇ T (t) ⁇ Tc ⁇ (1-e ( ⁇ t / ⁇ C) )... (1)
- the saturation rise temperature ⁇ Tc of the low heat resistant component is expressed by the following equation using the power consumption P of the resistors R1A and R1B and the thermal resistance ⁇ .
- ⁇ Tc P ⁇ ⁇ ... (2)
- the power consumption P of the resistors R1A and R1B is expressed by the following equation using the common ground current i and the resistance values r of the resistors R1A and R1B.
- P i 2 x r ... (3)
- the second microcomputer 24B can calculate the transient rise temperature ⁇ T (t) of the low heat resistant component in each control cycle by using the above equations (1) to (3). At this time, the count time after diagnosing that the resistance value increase abnormality has occurred in either the GND harness HA or the HB is substituted into the time t in the above equation (1). Further, the magnitude of the common ground current acquired based on the output voltage EB of the second current detection circuit 26B is substituted into the common ground current i of the above equation (3).
- the heat capacity C, thermal resistance ⁇ , and resistance value r which are the constants of the above equations (1) to (3), are obtained in advance by experiments, simulations, etc., and are stored in the ROM or the like of the second microcomputer 24B, and transiently rise. It is read from a ROM or the like and used when calculating the temperature ⁇ T (t).
- T (t) the transient absolute temperature T (t), which is the absolute temperature of the low heat-resistant component when the time t elapses after the common ground current starts to flow, is expressed by the following equation using the atmospheric temperature Ta.
- T (t) ⁇ T (t) + Ta ... (4)
- the second microcomputer 24B acquires and acquires the atmospheric temperature based on the output signal of the thermistor in each control cycle.
- the transient absolute temperature T (t) can be calculated by substituting the data into the atmospheric temperature Ta in the above equation (4).
- the transient absolute temperature T (t) of the low heat resistant component rises to a predetermined limit absolute temperature T lim , which is the absolute temperature allowed from the heat resistant performance of the low heat resistant component, that is, the absolute When the temperature condition is met, the current limit is started.
- the second microcomputer 24B determines the start timing of the current limitation based on the transient rise temperature ⁇ T (t) and the transient absolute temperature T (t), at least one of the rise temperature condition and the absolute temperature condition. When is satisfied, the current limitation may be started.
- At least one of the low heat resistant parts has a rising temperature condition and an absolute temperature condition.
- the current limit may be started when one is established.
- the second microcomputer 24B outputs a second inverter control signal that makes the output voltage EB less than the predetermined voltage Vth1 to limit the output of the second inverter 11B, or the second microcomputer 24B is the second power supply. This is performed with the relay 20B turned off. In order to ensure the protection of the low heat resistant component, the second microcomputer 24B may both limit the output of the second inverter 11B and turn off the second power supply relay 20B.
- the first microcomputer 24A generates a first inverter control signal based on PI control or the like so that the energization current of the motor 1 approaches the first target current value, as in the normal state, and the first inverter 11A. Maintain the output of.
- the common ground current decreases due to the current limitation of the second microcomputer 24B, the energization amount of the first GND harness HA to which the common ground current has flowed decreases, and the overheat protection of the first GND harness HA is performed. Can be planned.
- the first microcomputer 24A determines that a resistance increase abnormality has occurred in the first GND harness HA in the abnormality diagnosis, regardless of the set first target current value, the second microcomputer.
- the current limitation is started in the same manner as in 24B, and the common ground current is reduced.
- the second microcomputer 24B maintains the output of the second inverter 11B as in the normal state. As a result, the amount of electricity supplied to the second GND harness HB into which the common ground current has flowed is reduced, and overheating protection of the second GND harness HB can be achieved.
- FIG. 7 shows the current flowing through the ECU 2 when another abnormality processing for the abnormal state of FIG. 5 is performed.
- the second microcomputer 24B starts the current limitation of its own system as an abnormal processing, and therefore, it relates to the second electric system of the motor 1.
- the amount of energization decreases.
- the first microcomputer 24A normally outputs the output of the first inverter 11A by the same current control as in the normal state, the decrease in the amount of energization related to the second electric system of the motor 1 is the first electric system of the motor 1. It means that it is not supplemented by the amount of electricity related to.
- the first microcomputer 24A is used in the second electric system of the motor 1 when the target torque of the motor 1 is relatively low.
- the output of the first inverter 11A can be increased so as to compensate for the decrease in the amount of energization.
- the first microcomputer 24A is as follows when the first target current value is sufficiently lower than the allowable current value of the first GND harness HA. That is, the first microcomputer 24A sets the difference between the energization amount related to the second electric system of the motor 1 and the second target current value of the second electric system calculated by using the detected phase current of the second shunt resistor 21B. 1 Add to the target current value to set a new first target current value. However, when the new first target current value exceeds the allowable current value of the first GND harness HA, the new first target current value is reset to the allowable current value or a lower neighborhood value.
- the first microcomputer 24A performs current control so that the amount of energization related to the first electric system of the motor 1 approaches a new first target current value.
- the amount of energization related to the first electric system of the motor 1 is increased, and the torque generated by the motor 1 can be brought closer to the target torque, so that the functional limitation of the electric steering system 100 can be relaxed.
- the first microcomputer 24A has a rising temperature condition and an absolute temperature condition for an abnormal state in which the resistance value of the second GND harness HB is normal and the resistance value of the first GND harness HA is increasing. When at least one of them is satisfied, the current limitation of the own system is started as an abnormality processing, so that the amount of energization related to the first electric system of the motor 1 is reduced. Therefore, when the target torque of the motor 1 is relatively low, the second microcomputer 24B can increase the output of the second inverter 11B so as to compensate for the decrease in the energization amount related to the first electric system of the motor 1. can. As a result, the amount of energization related to the first electric system of the motor 1 is increased, and the torque generated by the motor 1 can be brought closer to the target torque, so that the functional limitation of the electric steering system 100 can be relaxed.
- FIG. 8 shows a main part of the internal configuration of the ECU 28 according to the second embodiment.
- the parts different from those of the first embodiment will be mainly described, and the description of the first embodiment will be applied to the other parts as long as there is no contradiction. Therefore, the same or similar configurations as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted or simplified.
- the current detection method of the ECU 28 is different from that of the ECU 2. That is, in the ECU 2, the microcomputer of the electric system in which the resistance value increase abnormality has occurred can acquire the magnitude and direction of the common ground current, but the microcomputer of the normal electric system can acquire only the direction of the common ground current and the common ground current. I can't get the size of. On the other hand, the ECU 28 makes it possible to acquire the magnitude and direction of the common ground current in any system.
- the first control circuit 12A includes a first current detection circuit 29A having a different current detection method from the first current detection circuit 26A. Further, the second control circuit 12B includes a second current detection circuit 29B having a different current detection method from the second current detection circuit 26B.
- the first current detection circuit 29A includes a differential amplifier circuit 30A, an absolute value circuit 31A, and a negative voltage detection circuit 32A.
- the differential amplifier circuit 30A is configured by using an operational amplifier that operates both positive and negative power supplies.
- the non-inverting input terminal (+) of this operational amplifier is connected to the side opposite to the control system common ground 13 with the resistor R1A of the first current-voltage conversion element 22A of the first branch negative electrode line 19A interposed therebetween.
- the inverting input terminal (-) of the operational amplifier is connected between the resistor R1A of the first current-voltage conversion element 22A and the control system common ground 13 in the first branch negative electrode line 19A.
- the operational amplifier amplifies the difference between the voltage input to the non-inverting input terminal (+) and the voltage input to the inverting input terminal (-), and transfers this amplified signal from the output terminal to the absolute value circuit 31A and the comparison circuit 32A.
- the absolute value circuit 31A is a circuit that converts the input amplification signal into the absolute value voltage EA1 and outputs the circuit.
- the negative voltage detection circuit 32A is a circuit configured to output two different positive voltages EA2 depending on whether the voltage of the input amplified signal is positive or negative. For example, when the voltage of the amplified signal is positive, the negative voltage detection circuit 32A is relatively A high voltage (Hi) is output, and a relatively low voltage (Lo) is output when the voltage of the amplified signal is negative.
- the second current detection circuit 29B has the same configuration as the first current detection circuit 29A, and has a differential amplifier circuit 30B, an absolute value circuit 31B, and an absolute value detection circuit 31B.
- the differential amplifier circuit 30B is configured by using an operational amplifier that operates both positive and negative power supplies.
- the non-inverting input terminal (+) of this operational amplifier is connected to the side opposite to the control system common ground 13 with the resistor R1B of the second current-voltage conversion element 22B of the second branch negative electrode line 19B interposed therebetween. Further, the inverting input terminal (-) of the operational amplifier is connected between the resistor R1B of the second current-voltage conversion element 22B and the control system common ground 13 in the second branch negative electrode line 19B.
- the operational amplifier amplifies the difference between the voltage input to the non-inverting input terminal (+) and the voltage input to the inverting input terminal (-), and transfers this amplified signal from the output terminal to the absolute value circuit 31B and the comparison circuit 32B.
- the absolute value circuit 31B is a circuit that converts the input amplification signal into the absolute value voltage EB1 and outputs the circuit.
- the negative voltage detection circuit 32B is a circuit configured to output two different positive voltages EB2 depending on whether the voltage of the input amplified signal is positive or negative. For example, when the voltage of the amplified signal is positive, the negative voltage detection circuit 32B is relatively A high voltage (Hi) is output, and a relatively low voltage (Lo) is output when the voltage of the amplified signal is negative.
- the first microcomputer 24A inputs the output voltage EA1 of the absolute value circuit 31A to the analog input terminal AD1, and inputs the output voltage EA2 of the negative voltage detection circuit 32A to the digital input terminal DI1. Then, the first microcomputer 24A acquires the magnitude of the common ground current based on the output voltage EA1 of the absolute value circuit 31A, and acquires the direction of the common ground current based on the output voltage EA2 of the negative voltage detection circuit 32A.
- the second microcomputer 24B inputs the output voltage EB1 of the absolute value circuit 31B to the analog input terminal AD1, and inputs the output voltage EB2 of the negative voltage detection circuit 32B to the digital input terminal DI1. Then, the second microcomputer 24B acquires the magnitude of the common ground current based on the output voltage EB1 of the absolute value circuit 31B, and acquires the direction of the common ground current based on the output voltage EB2 of the negative voltage detection circuit 32B.
- the common ground current is the first. It means that it is flowing from the electric system to the second electric system. Therefore, the first microcomputer 24A that has detected such output voltages EA1 and EA2 determines that the resistance value increase abnormality has occurred in the first GND harness HA.
- the common ground current is generated. It means that the current is flowing from the second electric system to the first electric system. Therefore, the first microcomputer 24A that has detected such output voltages EA1 and EA2 determines that the resistance value increase abnormality has occurred in the second GND harness HB.
- the second microcomputer 24B determines that the resistance value increase abnormality has occurred in the second GND harness HB.
- the output voltage EB1 of the absolute value circuit 31B is a predetermined voltage Vth2 or more and the output voltage EB2 of the negative voltage detection circuit 32B is a Lo voltage
- the common ground current is from the first electric system to the second electric system. It will be flowing to. Therefore, the second microcomputer 24B that has detected such output voltages EB1 and EB2 determines that the resistance value increase abnormality has occurred in the first GND harness HA.
- the resistance value increases in the GND harnesses 24A and 24B between the microcomputers 24A and 24B. It is assumed that the timing for determining that an abnormality has occurred will be different. Therefore, when the microcomputer of one electric system first detects the resistance value increase abnormality, the information of the abnormality detection is notified to the microcomputer of the other electric system.
- the microcomputers 24A and 24B determine that a resistance value increase abnormality has occurred in the GND harness of their own system, they do not immediately limit the current of the abnormal system, and as described above, the transient rise temperature ⁇ T (t) and the transient absolute temperature T ( The calculation of t) is started. Then, the microcomputer of the electric system in which the resistance value increase abnormality occurs in the GND harness starts the current limitation when at least one of the rising temperature condition and the absolute temperature condition is satisfied.
- the ECU 28 configured as described above, it is assumed that a failure occurs in the current detecting means in one of the electric systems. That is, in the first electric system, it is assumed that at least one of the resistor R1A of the first current-voltage conversion element 22A and the first current detection circuit 29A fails. Alternatively, in the second electric system, it is assumed that at least one of the resistor R1B and the second current detection circuit 29B of the second current-voltage conversion element 22B fails.
- the microcomputer of one electric system in which the current detecting means fails can acquire the magnitude and direction of the common ground current by using the normal current detecting means of the other electric system. Therefore, the ECU 28 is configured such that the first microcomputer 24A inputs the output voltage of the second current detection circuit 29B, and the second microcomputer 24B inputs the output voltage of the first current detection circuit 29A.
- the first microcomputer 24A inputs the output voltage EB1 of the absolute value circuit 31B to the analog input terminal AD2, and inputs the output voltage EB2 of the negative voltage detection circuit 32B to the digital input terminal DI2.
- the second microcomputer 24B inputs the output voltage EA1 of the absolute value circuit 31A to the analog input terminal AD2, and inputs the output voltage EA2 of the negative voltage detection circuit 32A to the digital input terminal DI2.
- Whether or not the current detecting means has failed can be determined by whether or not one of the output voltages EA1 and EA2 or the output voltages EB1 and EB2 deviates from the conceivable voltage range. For example, when the output voltage EA2 and the output voltage EB2 are both Hi voltage or Lo voltage, the common ground current is flowing in different directions, so that the current detecting means may be out of order. It can be judged that there is. Further, if the common ground currents acquired from the output voltage EA1 and the output voltage EB1 are significantly larger than the energization amount related to each electric system of the motor 1, the current detecting means may be out of order. Can be judged.
- the start of current limitation is delayed within a range in which the low heat resistant component does not exceed the limit of heat resistance and durability due to the temperature rise. This makes it possible to extend the time until the system function of the electric steering system is limited as much as possible.
- the microcomputer of one electric system in which the current detection means has a failure can acquire the magnitude and direction of the common ground current by using the normal current detection means of the other electric system, the current detection redundancy can be used. The reliability of the electric steering system can be improved.
- the current detecting means may be provided in only one of the electric systems. For example, omitting the second current-voltage conversion element 22B and the second current detection circuit 29B, the second microcomputer 24B can input the output voltages EA and EB of the first current detection circuit 29A.
- the resistance value increase abnormality is determined as the common ground current i in the above equation (3).
- the average value of the common ground current detected after that may be used. This is because the inverter output may change due to a change in the target torque or the like.
- the microcomputers 24A and 24B determine that the output voltages EA and EB deviate from the ground potential V0, or that the output voltages EA2 and EB2 are both Hi voltages, the following diagnosis is made. You may go. That is, the microcomputers 24A and 24B can determine that a resistance value increase abnormality has occurred in the GND harnesses of both electric systems and a short circuit to the body ground or the like has occurred in the control system common ground 13.
- the ECU 28 instead of the microcomputer of one electric system inputting the output voltage from the current detection circuit of the other electric system, another current detection circuit is provided in the control circuit of one electric system, and this another current detection circuit is provided.
- the voltage across the resistor of the other electrical system may be input to.
- the first control circuit 12A instead of the first microcomputer 24A directly inputting the output voltages EB1 and EB2 of the second current detection circuit 29B, the first control circuit 12A includes another current detection circuit and a resistor in this other current detection circuit. The voltage across R1B may be input.
- the first microcomputer 24A can input the output voltage of the first current detection circuit 29A and the output voltage of another current detection circuit, and diagnose the resistance value increase abnormality using the normal output voltage. .. The same applies to the second microcomputer 24B.
- the above-mentioned predetermined voltages V th1 and V th2 are set as output voltages when the common ground current flowing when the difference between the two resistance values of the GND harness HA and HB is a predetermined value is detected by the current detection circuit. May be good.
- the predetermined value is defined as the difference between the two resistance values of the GND harness HA and HB when a common ground current that makes the saturation rise temperature ⁇ Tc of the low heat resistant parts of the ECUs 2 and 28 equal to the limit rise temperature ⁇ T lim is generated. can do.
- the predetermined value is defined in this way if the common ground current keeps the saturation rise temperature ⁇ Tc below the limit rise temperature ⁇ T lim , there is almost no possibility that the low heat resistant component exceeds the durability limit.
- the predetermined value is the GND harness HA when generating a common ground current that makes the saturation absolute temperature Tc, which is the sum of the saturation rise temperature ⁇ Tc of the low heat resistant component of the ECU 2 and the ambient temperature Ta, equal to the limit absolute temperature Tlim .
- HB can be specified as the difference between the two resistance values.
- the reason why the predetermined value is specified in this way is that if the common ground current keeps the saturated absolute temperature Tc less than the limit absolute temperature T lim , there is almost no possibility that the low heat resistant component exceeds the heat resistance limit.
- the above predetermined value may be set as follows when the current limitation is started when at least one of the rising temperature condition and the absolute temperature condition is satisfied. That is, as the difference between the predetermined value defined as the difference between the two resistance values when the saturation rise temperature ⁇ Tc becomes the limit rise temperature ⁇ T lim and the difference between the two resistance values when the saturation absolute temperature Tc becomes the limit absolute temperature T lim .
- the lower of the two predetermined values, which is the specified predetermined value, can be selected.
- the two resistances of the GND harness HA and HB are used. It can be assumed that the difference between the values is the above-mentioned predetermined value. Therefore, as the common ground current i in the above equation (3), a known current value of the common ground current that flows when the difference between the two resistance values of the GND harness HA and HB is the above-mentioned predetermined value may be used.
- the electric steering system 100 was made redundant in two electric systems, but it may be made redundant in three or more electric systems. Even in the ECU of the electric steering system 100 having three or more electric systems, the common ground current flowing into the normal electric system from a part of the electric systems in which the resistance value increase abnormality has occurred in the GND harness is detected by the above current detecting means. It is detectable. Then, the start of current limitation can be delayed within a range in which the low heat resistant component does not exceed the limits of heat resistance and durability.
- ECUs 2 and 28 that control the drive of the motor 1 in the electric steering system 100 are exemplified.
- an electronic control device may be provided with a current detecting means for detecting a common ground current by independently performing energization control for each electric system in an in-vehicle system redundantly configured in a plurality of electric systems. If so, it can be applied to any in-vehicle system.
- 2nd current detection circuit 62A ... 1st power supply negative electrode line, 62B ... 2nd Power supply negative electrode line, CA ... 1st winding set, CB ... 2nd winding set, HA ... 1st GND harness, HB ... 2nd GND harness, R1A, R1B ... Resistor, EA, EA1, EA2 ... 1st current detection circuit Output voltage, EB, EB1, EB2 ... Output voltage of the second current detection circuit, ⁇ T (t) ... Transient rise temperature
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Abstract
Description
図1は、第1実施形態における電動ステアリングシステムの一例を示す。電動ステアリングシステム100は、運転者がステアリング操作を行う車両1000の通常運転では、ステアリングホイール1001による操舵トルクで一対の操向輪1002を転舵させる際に、操舵トルクをアシストするパワーステアリングとして機能する。
また、ECU2のハウジング10の内部には、第2車載バッテリ7Bを電源とする第2電気系統として、モータ1の巻線のうち後述する第2巻線組を駆動する第2インバータ11Bと第2インバータ11Bの出力を制御する第2制御回路12Bとが収容される。
第1制御回路12Aおよび第2制御回路12BはECU2内の制御系共通グランド13によりグランドを共有している。
第2正極コネクタ14Bは、第2電源正極ライン61Bを介して第2車載バッテリ7Bの正極に電気的に接続され、第2負極コネクタ15Bは、第2電源負極ライン62Bを介して第2車載バッテリ7Bの負極に電気的に接続される。
第2正極コネクタ14Bは、ECU2のハウジング10の内部において、第2正極ライン16Bを介して第2インバータ11Bの正極側母線に電気的に接続される。第2正極ライン16Bから分岐する第2分岐正極ライン17Bは、第2制御回路12Bのうち後述する電源回路に電気的に接続される。第2分岐正極ライン17Bは、第2正極コネクタ14Bの内部で第2正極ライン16Bから分岐してもよい。
第2負極コネクタ15Bは、ECU2のハウジング10の内部において、第2負極ライン18Bを介して第2インバータ11Bの負極側母線と電気的に接続される。第2負極ライン18Bから分岐する第2分岐負極ライン19Bは制御系共通グランド13に電気的に接続される。これにより、第2インバータ11Bの負極側母線および制御系共通グランド13は、第2GNDハーネスHBを介して第2車載バッテリ7Bの負極と電気的に接続される。第2分岐負極ライン19Bは、第2負極コネクタ15Bの内部で第2負極ライン18から分岐してもよい。
第2正極ライン16Bのうち第2分岐正極ライン17Bの分岐点よりも第2インバータ11B側には、第1電源リレー20Aと同様の第2電源リレー20Bが配置される。第2電源リレー20Bは、外部から入力した制御信号に応じてオンおよびオフ動作し、オン状態のときに第2車載バッテリ7Bから第2インバータ11Bへ電源供給がなされ、オフ状態のときに第2車載バッテリ7Bから第2インバータ11Bへの電源供給が遮断される。
第2負極ライン18Bのうち第2分岐負極ライン19Bの分岐点よりも第2インバータ11B側には、モータ1の巻線のうち後述する第2巻線組に流れる相電流を検出するための第2シャント抵抗器21Bが配置される。
第2分岐負極ライン19Bには、これに流れる電流すなわち共通グランド電流を検出するための第2電流-電圧変換素子22Bが配置される。
第2制御回路12Bは、第2インバータ11Bの出力を制御するものであり、第2電源回路23B、第2マイクロコンピュータ(以下、「第2マイコン」という)24Bおよび第2駆動回路25B、第2電流検出回路26B等を備える。
電源回路23A,23B、マイコン24A,24B、駆動回路25A,25Bはそれぞれ制御系共通グランド13に接続されている。
第2電源回路23Bは、第2分岐正極ライン17Bと電気的に接続されて第2車載バッテリ7Bの電源電圧が印加され、例えば5ボルトの第2内部電源電圧VBを生成する。第2内部電源電圧VBは、第2マイコン24B、第2駆動回路25Bおよび第2電流検出回路26Bへ供給される。第2分岐正極ライン17Bには、第2電源回路23Bから第2正極コネクタ14Bへの逆流を抑制すべくダイオードDBが配置される。
第2マイコン24Bは、第2シャント抵抗器21Bで検出された相電流の検出値に基づいてモータ1の第2電気系統に係る通電量を算出し、この通電量が第2目標電流値に近づくように電流制御を行う。具体的には、第2マイコン24Bは、PI制御等を用いて、第2電気系統に係る通電量と第2目標電流値との偏差に基づいて、第2インバータ制御信号を生成する。この第2インバータ制御信号は、第2インバータ11Bの出力を制御するための信号である。
マイコン24A,24Bで生成されるインバータ制御信号としては、例えばPWM(Pulse Width Modulation)信号が生成される。マイコン24A,24Bはそれぞれ生成したインバータ制御信号をデジタル出力端子DO1から出力する。
第2駆動回路25Bは、第2マイコン24Bのデジタル出力端子DO1から出力された第2インバータ制御信号を、第2インバータ11Bのスイッチング素子を駆動するためのゲート駆動信号に変換して出力する。
ΔT(t)=ΔTc×(1-e(-t/θC))…(1)
ΔTc=P×θ…(2)
P=i2×r…(3)
T(t)=ΔT(t)+Ta…(4)
図8は、第2実施形態に係るECU28の内部構成の要部を示す。なお、本実施形態では、主に第1実施形態と異なる部分について説明し、その他の部分については矛盾が生じない限りにおいて第1実施形態に関する説明が適用される。したがって、第1実施形態と同一ないし類似の構成には同一の符号を付して、その説明を省略ないし簡潔にする。
第2マイコン24Bは、絶対値回路31Bの出力電圧EB1をアナログ入力端子AD1に入力し、負電圧検出回路32Bの出力電圧EB2をデジタル入力端子DI1に入力する。そして、第2マイコン24Bは、絶対値回路31Bの出力電圧EB1に基づいて共通グランド電流の大きさを取得し、負電圧検出回路32Bの出力電圧EB2に基づいて共通グランド電流の方向を取得する。
一方、絶対値回路31Aの出力電圧EA1が零から乖離し(具体的には所定電圧Vth2以上となり)、かつ、負電圧検出回路32Aの出力電圧EA2がLo電圧であるときには、共通グランド電流が第2電気系統から第1電気系統へ流れていることになる。したがって、このような出力電圧EA1,EA2を検出した第1マイコン24Aは、第2GNDハーネスHBに抵抗値増大異常が発生していると判定する。
一方、絶対値回路31Bの出力電圧EB1が所定電圧Vth2以上であり、かつ、負電圧検出回路32Bの出力電圧EB2がLo電圧であるときには、共通グランド電流が第1電気系統から第2電気系統へ流れていることになる。したがって、このような出力電圧EB1,EB2を検出した第2マイコン24Bは、第1GNDハーネスHAに抵抗値増大異常が発生していると判定する。
Claims (10)
- 電子制御装置であって、
第1電源に接続された第1正極コネクタおよび第1負極コネクタと、
第2電源に接続された第2正極コネクタおよび第2負極コネクタと、
前記第1正極コネクタおよび前記第1負極コネクタに接続され、電動モータの第1巻線組に通電して駆動する第1インバータと、
前記第2正極コネクタおよび前記第2負極コネクタに接続され、前記電動モータの第2巻線組に通電して駆動する第2インバータと、
前記第1負極コネクタと前記第2負極コネクタとに接続されるグランド部と、
前記第1負極コネクタと前記グランド部との間、または、前記第2負極コネクタと前記グランド部との間に設けられたセンサ部と、
前記センサ部の出力信号に基づいて、前記第1負極コネクタと前記第2負極コネクタとの間で前記グランド部を介して流れる電流を検出可能な電流検出回路と、
マイクロコンピュータであって、
前記第1正極コネクタおよび前記第1負極コネクタに接続され、前記第1インバータの出力を制御する第1マイクロコンピュータと、
前記第2正極コネクタおよび前記第2負極コネクタに接続され、前記第2インバータの出力を制御する第2マイクロコンピュータと、
を有し、
前記第1マイクロコンピュータおよび前記第2マイクロコンピュータは、前記電流検出回路の出力電圧に基づいて前記電子制御装置の内部の上昇温度を推定し、
前記第1マイクロコンピュータが前記上昇温度に基づいて前記第1インバータから出力される電流の制限を開始するか、あるいは、前記第2マイクロコンピュータが前記上昇温度に基づいて前記第2インバータから出力される電流の制限を開始する、
マイクロコンピュータと、
を備えた電子制御装置。 - 前記センサ部は、第1センサ部と第2センサ部とを有し、
前記電流検出回路は、前記第1センサ部の出力信号を入力する第1電流検出回路と前記第2センサ部の出力信号を入力する第2電流検出回路とを有し、
前記第1センサ部は、前記第1負極コネクタと前記グランド部との間に設けられ、
前記第2センサ部は、前記第2負極コネクタと前記グランド部との間に設けられ、
前記第1電流検出回路の出力電圧は、前記第1マイクロコンピュータに入力され、
前記第2電流検出回路の出力電圧は、前記第2マイクロコンピュータに入力される、
請求項1に記載の電子制御装置。 - 前記電子制御装置の内部の上昇温度は、前記第1センサ部の上昇温度、および、前記第2センサ部の上昇温度である、請求項2に記載の電子制御装置。
- 前記第1インバータから出力される電流の制限または前記第2インバータから出力される電流の制限は、前記第1負極コネクタから前記第1電源までの第1グランドハーネスの抵抗値と前記第2負極コネクタから前記第2電源までの第2グランドハーネスの抵抗値との差分が所定値以上であるときに行う、請求項3に記載の電子制御装置。
- 前記第1マイクロコンピュータは、前記第1負極コネクタから前記第1電源までの第1グランドハーネスと前記第2負極コネクタから前記第2電源までの第2グランドハーネスとのうち前記第1グランドハーネスに異常が発生している場合に、前記第1センサ部の上昇温度に基づいて前記第1インバータから出力される電流の制限を開始するとともに、前記第2マイクロコンピュータは、前記第2インバータから出力される電流を増大させる、請求項3に記載の電子制御装置。
- 前記第1インバータ、前記第1センサ部、前記第1電流検出回路および前記第1マイクロコンピュータと、前記第2インバータ、前記第2センサ部、前記第2電流検出回路および前記第2マイクロコンピュータと、で別々の電気系統を構成し、
前記マイクロコンピュータは、前記第1電流検出回路の出力電圧と前記第2電流検出回路の出力電圧とに基づいて、前記第1センサ部および前記第1電流検出回路、または、前記第2センサ部および前記第2電流検出回路の異常を検出可能であり、前記第1センサ部および前記第1電流検出回路に異常を検出したときに、前記第1センサ部および前記第1電流検出回路と同じ電気系統の前記第1マイクロコンピュータは、前記異常が検出されなかった前記第2センサ部の出力信号を入力する、第1電流検出回路とは別の電流検出回路の出力電圧、または、前記第2電流検出回路の出力電圧に基づいて、前記上昇温度を推定する、
請求項2に記載の電子制御装置。 - 前記第1マイクロコンピュータは、前記第1センサ部の上昇温度が、前記第1センサ部の耐ヒートサイクル性能から許容される上昇温度である所定の限界上昇温度まで上昇したときに、前記第1インバータから出力される電流の制限を開始する一方、
前記第2マイクロコンピュータは、前記第2センサ部の上昇温度が、前記第2センサ部の耐ヒートサイクル性能から許容される上昇温度である所定の限界上昇温度まで上昇したときに、前記第2インバータから出力される電流の制限を開始する、
請求項3に記載の電子制御装置。 - 前記第1マイクロコンピュータは、前記第1センサ部の上昇温度に雰囲気温度を加算した過渡絶対温度が、前記第1センサ部の耐熱性能から許容される絶対温度である所定の限界絶対温度まで上昇したときに、前記第1インバータから出力される電流の制限を開始する一方、
前記第2マイクロコンピュータは、前記第2センサ部の上昇温度に雰囲気温度を加算した過渡絶対温度が、前記第2センサ部の耐熱性能から許容される絶対温度である所定の限界絶対温度まで上昇したときに、前記第2インバータから出力される電流の制限を開始する、
請求項3に記載の電子制御装置。 - 前記第1マイクロコンピュータは、前記第1グランドハーネスに異常が発生してからの前記第1電流検出回路の出力電圧の平均値に基づいて、前記第1センサ部の上昇温度を推定し、
前記第2マイクロコンピュータは、前記第2グランドハーネスに異常が発生してからの前記第2電流検出回路の出力電圧の平均値に基づいて、前記第2センサ部の上昇温度を推定する、
請求項5に記載の電子制御装置。 - 前記差分が前記所定値以上であるか否かは、前記第1電流検出回路または前記第2電流検出回路で検出された電流に基づいて判定される、請求項4に記載の電子制御装置。
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