JP2007223436A - Relay circuit and electric power steering control device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the whole system from being unactuated by the abnormality of continuity because foreign matter is caught between relay contact points in a relay circuit or the contact points are oxidized or the like. <P>SOLUTION: Relay circuits RLY1-PLY3 comprises the relay circuit having a bidirectional contact point structure with a neutral position. When carrying out continuity control, a moving contact point tm of the relay circuits RLY1-RLY3 is conducted with one fixed contact point t1. As the result of the continuity confirmation a connecting destination of the moving contact point tm is switched to the other fixed contact point t2 in case of abnormality. As the result of the continuity confirmation, the abnormality of continuity between the moving contact point tm and the fixed contact point t1 is recorded in case of normality. Power is supplied through the moving contact point tm and the fixed contact point t2. An alarm device 30 is actuated when the connections between the moving contact point tm and the fixed contact points t1 and t2 are all abnormally conducted in any one of the relay circuits RLY1-RLY3. An operator is notified of the abnormality of continuity of an interrupting circuit 27. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a relay capable of avoiding a system down due to a malfunction of a relay circuit provided in a power supply line for supplying electric power to an electric motor that applies a steering assist force to a steering system. The present invention relates to a circuit and an electric power steering control device.

In this type of electric power steering control device, a relay circuit is provided in a power supply line for supplying power to an electric motor for applying a steering assist force to a steering system, and drive control of the electric motor is performed. When an abnormality in the drive control device or the electric motor is detected, the relay circuit is shut off, so that the electric motor malfunctions and a steering assist force unintended by the driver is applied to the steering system. I try to avoid it. In addition, the welding abnormality of the relay circuit, the detection of foreign matter between the relay contacts, and the like are performed (see, for example, Patent Document 1).
JP 2002-240655 A

By the way, as described above, it is possible to detect whether or not the relay circuit is actually in a conductive state by detecting the foreign matter between the relay contacts. However, if the relay circuit does not actually become conductive due to foreign matter or the like, power supply to the electric motor is not performed as it is, so an assist process for applying a steering assist force to the steering system is performed. I can't do it. In other words, even if the system itself as an electric power steering control device is in a state where it can operate normally, foreign matter is mixed between the relay contacts, and the system cannot be operated because the entire system cannot be operated. The assist process cannot be performed. For this reason, there has been a demand for an electric power steering control device that can further improve the reliability of the system without causing the system to be down due to the influence of foreign matters or the like.
Therefore, the present invention has been made by paying attention to the above-mentioned conventional unsolved problems, and it is possible to avoid the fact that the system itself is normal but cannot be conducted due to the influence of foreign matter or the like. An object of the present invention is to provide a relay circuit and an electric power steering control device using the relay circuit.

  In order to achieve the above object, a relay circuit according to claim 1 of the present invention is a relay circuit that is interposed between a first circuit and a second circuit and is capable of conducting and blocking between them. A first state of conducting between a first coupling point on the side connected to the first circuit of the relay circuit and a second coupling point on the side connected to the second circuit; Conductivity between the first coupling point and the second coupling point, and wiring between the first coupling point and the second coupling point is the first coupling point in the first state and In a position where the second state in parallel with the wiring between the second coupling points, the wiring in the first state, and the wiring on the wiring in the second state are separated from each other. It is possible to realize a third state in which each is independently blocked.

  According to the first aspect of the present invention, the relay circuit inserted between the first circuit and the second circuit is configured to be able to realize the first state, the second state, and the third state. Has been. In the first state, the relay circuit is electrically connected between the first coupling point on the side connected to the first circuit and the second coupling point on the side connected to the second circuit. In the state of 2, the conduction between the first coupling point and the second coupling point is established, and the wiring between the first coupling point and the second coupling point is the first coupling point in the first state. And it is in a parallel relationship with the wiring between the second coupling points. For this reason, for example, even when the conduction between the first coupling point and the second coupling point becomes impossible in the first state, by realizing the second state, the first coupling point and It becomes possible to conduct between the second coupling points. That is, when only one of the first state and the second state becomes a conduction abnormality, the relay circuit can be conducted by realizing the other state, and both the first state and the second state are Since the relay circuit is not able to conduct for the first time when the conduction abnormality occurs, the possibility that the relay circuit cannot be conducted is reduced.

The relay circuit according to claim 2 is characterized in that the first state, the second state, and the third state are realized by a bidirectional contact structure with a neutral position.
According to a third aspect of the present invention, there is provided a relay circuit comprising: opening / closing means capable of conducting and blocking between the first coupling point and the second coupling point; and between the first coupling point and the second coupling point. The first state, the second state by the short-circuit means capable of short-circuiting, and the switching means for interposing either the opening / closing means or the short-circuit means between the first coupling point and the second coupling point And the third state are realized.

According to a fourth aspect of the present invention, there is provided a relay circuit connected in parallel to the first opening / closing means capable of conducting and blocking between the first coupling point and the second coupling point, and the first opening / closing means. The first state, the second state, and the third state are realized by second opening / closing means capable of conducting and blocking between the first coupling point and the second coupling point. It is said.
In the invention according to any one of claims 2 to 4, a bidirectional contact structure with a neutral position is used, or between the first coupling point and the second coupling point, they can be conducted or cut off. The first opening / closing means and the second opening / closing means and the second opening / closing means which can selectively connect or disconnect between the first coupling point and the second coupling point by the switching means, or the short-circuiting means for short-circuiting them. By providing the opening / closing means in parallel between the first coupling point and the second coupling point, the first to third states can be easily realized.

The relay circuit according to claim 5 is characterized in that electrical characteristics between the first coupling point and the second coupling point in the first state and the second state are the same. Yes.
In the invention according to claim 5, since the electrical characteristics between the first coupling point and the second coupling point are the same in both the first state and the second state, the first coupling point and the second coupling point The electrical characteristics of the relay circuit do not change regardless of whether the two coupling points are conducted in either the first state or the second state.

The relay circuit according to claim 6 is characterized in that the first switching means has a mechanical contact and the second switching means has an electrical contact.
In the invention according to claim 6, since the first opening / closing means and the second opening / closing means have mechanical contacts and electrical contacts, respectively, and have different types of contacts, the first opening / closing means and the first opening / closing means The possibility that the two opening / closing means cannot conduct at the same timing is reduced.

Furthermore, the relay circuit according to claim 7 is characterized in that a mechanical contact is inserted in the wiring in the first state.
In the seventh aspect of the present invention, mechanical contacts are inserted in the wiring in the first state, and in particular, the mechanical contacts may be unable to conduct due to contamination of foreign matters or oxidation of the contacts. There is. In the first state, if the mechanical contact cannot be conducted, switching to the second state makes the conduction between the first coupling point and the second coupling point impossible. The possibility of being unable to conduct is reduced.

  According to an eighth aspect of the present invention, there is provided an electric power steering control device comprising: an electric motor for applying a steering assist force to a steering system; motor drive control means for driving and controlling the electric motor; and driving the electric motor. A power supply relay circuit comprising the relay circuit according to any one of claims 1 to 7 inserted in a power supply line for control, and the power supply relay circuit is controlled. A relay circuit control unit; and a continuity abnormality detection unit that detects a continuity abnormality of the relay circuit for power supply, wherein the relay circuit control unit performs the power supply relay when supplying power to the electric motor. The circuit is switched to the first state, and when the continuity abnormality detecting means detects the continuity abnormality of the power supply relay circuit in the first state, the power supply relay circuit It is characterized in that switching to the second state.

  According to the eighth aspect of the invention, when power is supplied to the electric motor, the power supply relay circuit inserted in the power supply line is switched to the first state, and the power supply relay circuit The connection point of 1 and the second connection point are conducted. In this first state, when a conduction abnormality between the first coupling point and the second coupling point is detected, the power supply relay circuit is switched to the second state, whereby the first coupling point is It becomes possible to conduct between the point and the second coupling point. That is, when only one of the first state and the second state is disabled, the power supply relay circuit is turned on by realizing the other state, and the first state and the second state. Since the power supply relay circuit is disabled only when both of the states become non-conductive, it is possible to reduce the possibility that the power supply relay circuit becomes non-conductive.

Further, in the electric power steering control device according to claim 9, the continuity abnormality detecting means detects the continuity abnormality of the power supply relay circuit only when the continuity abnormality is detected in both the first state and the second state. It is characterized by notifying as a continuity abnormality.
In the invention according to claim 9, the continuity abnormality of the power supply relay circuit is notified only when both the first state and the second state become continuity abnormality, and the first state and the second state When only one of these is abnormal in continuity, it is not notified as a continuity abnormality in the relay circuit for power supply. Therefore, in a state where power can be supplied by realizing a conductive state among the first state and the second state. In spite of this, it is determined that the power supply relay circuit is abnormal in conduction and the electric power steering control device is prevented from going down.

  According to a tenth aspect of the present invention, an electric power steering control device includes an electric motor that applies a steering assist force to a steering system, motor drive control means that drives and controls the electric motor, and the electric motor. A power supply relay circuit that is inserted into a power supply line for control and is controlled to be in a conductive state when power is supplied to the electric motor, and relay circuit control means for controlling the power supply relay circuit And the power supply relay circuit is capable of conducting and blocking between a first coupling point and a second coupling point connected to the power supply line of the power supply relay circuit. And the second switching means connected in parallel with the first opening and closing means and capable of conducting and blocking between the first coupling point and the second coupling point. System The means is an electric power steering control device for controlling both the first opening / closing means and the second opening / closing means to be in a conductive state when the power is supplied, wherein the first opening / closing means and the second opening / closing means A conduction abnormality detecting means for individually detecting a conduction abnormality of the means, and when the conduction abnormality is detected only in any one of the first opening / closing means and the second opening / closing means in the conduction abnormality detection stage; Control amount limiting means for limiting the drive control amount of the electric motor by the motor drive control means.

  According to the tenth aspect of the present invention, the first opening / closing means for conducting or blocking the power supply line between the first coupling point and the second coupling point of the power supply relay circuit. When the first opening / closing means is connected in parallel with the first opening / closing means and the second opening / closing means is electrically connected to or disconnected from the first opening / closing means, and the electric power is supplied to the electric motor, the first opening / closing means and second Both of the opening / closing means are controlled to be in a conductive state, and power is supplied through both the route passing through the first opening / closing means and the route passing through the second opening / closing means. When the conduction abnormality is detected only for one of the first opening / closing means and the second opening / closing means, that is, by only one of the first opening / closing means and the second opening / closing means. When the power supply to the electric motor is possible, the drive control amount of the electric motor is limited by the motor drive control means. For this reason, the steering assist force is suppressed by supplying power corresponding to the drive control amount limited by the motor drive control means through either the first opening / closing means or the second opening / closing means. Steering assistance can be performed.

According to an eleventh aspect of the present invention, there is provided the electric power steering control device according to the present invention, wherein the continuity abnormality detecting means has a predetermined time during which the first opening / closing means and the second opening / closing means can be regarded as actually switched to the conducting state. It is characterized in that each abnormality detection is performed at each elapsed timing.
In the eleventh aspect of the present invention, even when the first opening / closing means and the second opening / closing means are conduction-controlled at the same timing, the types of the first opening / closing means and the second opening / closing means are different. In some cases, the timing at which these actually switch to the conductive state is different. By determining whether or not the first opening / closing means and the second opening / closing means are conducted at a timing corresponding to the time required until each of the first opening / closing means and the second opening / closing means is actually switched. Misjudgment caused by the fact that the abnormality judgment is made before actually switching to the conductive state is avoided.

The electric power steering control device according to claim 12 is characterized in that the first opening / closing means has a mechanical contact and the second opening / closing means has an electrical contact.
In the twelfth aspect of the invention, the first opening / closing means has a mechanical contact, the second opening / closing means has an electrical contact, and the first opening / closing means and the second opening / closing means are Since the types are different, the possibility that both the first opening / closing means and the second opening / closing means become abnormal in conduction due to, for example, the formation of an insulating film is reduced, and the electric power supply relay may not be conductive. Will be reduced.

Furthermore, the electric power steering control device according to claim 13 is characterized in that the continuity abnormality detecting unit detects the continuity abnormality only when both the first opening and closing unit and the second opening and closing unit detect the continuity abnormality. It is characterized by notifying that the circuit is abnormally connected.
In the invention according to claim 13, only when the first opening / closing means and the second opening / closing means both become abnormal in conduction, it is notified as abnormal conduction in the relay circuit for power supply, and the first opening / closing means and When only one of the two open / close means is abnormal in conduction, the power supply relay circuit is not notified of the abnormal conduction. Therefore, the power through the open / close means that can be conducted between the first open / close means and the second open / close means. Although the supply is possible, it is determined that the relay circuit for power supply is abnormal in conduction and the electric power steering control device is prevented from going down.

  According to the relay circuit according to the first to fourth aspects of the present invention, the first state of conducting between the first coupling point and the second coupling point of the relay circuit, the first coupling point, Conductivity between the second coupling point and the wiring between the first coupling point and the second coupling point are in parallel with the wiring between the first coupling point and the second coupling point in the first state. And a third state in which the wirings are independently cut off at positions where the wirings are separated on the wirings in the first state and the wirings in the second state. Since the first circuit and the second state are switched, the relay circuit cannot be turned on for the first time when both the first state and the second state are turned off. The possibility that the circuit cannot be conducted can be reduced.

In the relay circuit according to claim 5, since the electrical characteristics between the first coupling point and the second coupling point in the first state and the second state are the same, the first coupling Even when the point and the second coupling point are made to conduct in either the first state or the second state, it is possible to avoid the change in the electrical characteristics of the relay circuit.
According to the relay circuit of the sixth aspect, the first opening / closing means and the second opening / closing means each have a mechanical contact and an electrical contact, and have different types of contacts. It is possible to reduce the possibility that the means and the second opening / closing means cannot conduct at the same timing.

  Further, according to the relay circuit of the seventh aspect, the mechanical contact is inserted in the wiring between the first coupling point and the second coupling point in the first state, so that foreign matter is mixed and the contact is oxidized. Even if there is a possibility that conduction failure may occur due to, etc., if the conduction abnormality is detected in the first state, switching to the second state reduces the possibility that the relay circuit will become conduction abnormality can do.

  According to the electric power steering control device of the eighth aspect of the present invention, the first state in which the first coupling point and the second coupling point are electrically connected, and the first coupling in the first state. A second state in which the wiring between the point and the second coupling point is in parallel with the wiring between the first coupling point and the second coupling point in the first state, and the wiring in the first state; When supplying power to the electric motor with a relay circuit capable of realizing the third state in which the wirings are independently cut off at the positions where the wirings are separated from each other in the second state. Applied to a relay circuit for power supply controlled to a conduction state, and when a conduction abnormality occurs in the first state, the state is switched to the second state and power is supplied via the second state. From the first state and the second state Since the power supply relay circuit becomes a continuity abnormality for the first time when both of them become continuity abnormalities, the possibility of the power supply relay circuit becoming a continuity abnormality can be reduced. The possibility of going down can be reduced.

  Further, according to the electric power steering control device of the ninth aspect, since the continuity abnormality of the power supply relay circuit is notified only when the continuity abnormality is detected in both the first state and the second state, The power supply relay circuit is determined to be abnormal in conduction even though the electric power can be supplied by realizing the conductive state of the first state and the second state, and the electric power steering control device It is possible to avoid going down.

  According to the electric power steering control device of the tenth aspect of the present invention, the power supply relay circuit includes the first opening / closing means and the second opening / closing means connected in parallel therewith, When power is supplied to the motor, power is supplied via both the first opening / closing means and the second opening / closing means, and only one of the first opening / closing means and the second opening / closing means detects a conduction abnormality. In this case, since the motor drive control means limits the drive control amount of the electric motor, the steering assist force is suppressed by supplying power through the opening / closing means that does not cause a conduction abnormality. Can provide steering assistance.

According to the electric power steering control device of the eleventh aspect, the first opening and closing means and the first opening and closing means and the second opening and closing means at the timing corresponding to the time required until the switching is actually performed. Since it is determined whether or not the second opening / closing means is conductive, it is possible to avoid erroneous determination as a conduction abnormality.
Further, according to the electric power steering control device of the twelfth aspect, since the first opening / closing means and the second opening / closing means are of different types, both of the first opening / closing means and the second opening / closing means are abnormal in conduction. That is, the possibility that the relay for power supply cannot be conducted and the electric power steering control device will be down can be reduced.

  Furthermore, according to the electric power steering control device of the thirteenth aspect of the present invention, only when both the first opening / closing means and the second opening / closing means detect the conduction abnormality, they are notified as the conduction abnormality of the power supply relay circuit. The power supply relay circuit is determined to be abnormal in conduction even though the power supply is possible through the conductive switching means among the first switching means and the second switching means, and the electric power steering. It is possible to avoid a system failure of the control device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment will be described.
FIG. 1 is an overall configuration diagram showing an embodiment of an electric power steering apparatus to which the present invention is applied. In the figure, 1 is a steering wheel, and a steering force applied to the steering wheel 1 from a driver. Is transmitted to the steering shaft 2 having the input shaft 2a and the output shaft 2b. The steering shaft 2 has one end of the input shaft 2a connected to the steering wheel 1 and the other end connected to one end of the output shaft 2b via a torque sensor 3 as steering torque detecting means.

  The steering force transmitted to the output shaft 2 b is transmitted to the lower shaft 5 via the universal joint 4 and further transmitted to the pinion shaft 7 via the universal joint 6. The steering force transmitted to the pinion shaft 7 is transmitted to the tie rod 9 via the steering gear 8 and steers steered wheels (not shown). Here, the steering gear 8 is configured in a rack and pinion type having a pinion 8a connected to the pinion shaft 7 and a rack 8b meshing with the pinion 8a, and the rotational motion transmitted to the pinion 8a is linearly moved by the rack 8b. It has been converted to movement.

A steering assist mechanism 10 for transmitting a steering assist force to the output shaft 2b is connected to the output shaft 2b of the steering shaft 2. The steering assist mechanism 10 includes a reduction gear 11 coupled to the output shaft 2b and a three-phase brushless motor 12 that generates a steering assist force coupled to the reduction gear 11.
The torque sensor 3 detects the steering torque applied to the steering wheel 1 and transmitted to the input shaft 2a. For example, the torsion bar (not shown) in which the steering torque is interposed between the input shaft 2a and the output shaft 2b is used. It converts into angular displacement, and it is comprised so that this torsional angular displacement may be converted into resistance change or magnetic change and detected.

  As shown in FIG. 2, the three-phase brushless motor 12 has, for example, one end of a U-phase coil, a V-phase coil, and a W-phase coil connected to each other to form a star connection, and the other end of each coil is a steering assist. The motor drive currents Iu, Iv and Iw are individually connected to the control device 20, and a rotor position detection circuit 13 including a hall element, a resolver and the like for detecting the rotational position of the rotor is provided.

  The torque detection value T output from the torque sensor 3 and the rotor rotation angle θ detected by the rotor position detection circuit 13 are input to the steering assist control device 20 and the vehicle speed detected by the vehicle speed sensor 21. The detection value V is also input to the steering assist control device 20, and any two of the motor drive currents Iu, Iv, and Iw supplied to each phase coil of the three-phase brushless motor 12, for example, Iu and Iw The motor drive current detection values Iud and Iwd output from the motor current detection circuit 22 for detecting the signal are input.

  The steering assist control device 20 calculates a steering assist current target value based on the torque detection value T, the vehicle speed detection value V, the motor current detection values Iud and Iwd, and the rotor rotation angle θ, and calculates the current command value Iut, Ivt and Iwt, and a control arithmetic unit 23 that outputs a PWM (pulse width modulation) signal having a duty ratio Du, Dv, and Dw determined based on the current command values Iut, Ivt, and Iwt, and a three-phase brushless motor 12 are driven. A motor drive circuit 24 composed of a field effect transistor (FET), and an FET gate drive for controlling the gate current of the field effect transistor of the motor drive circuit 24 based on the current command values Iut, Ivt and Iwt from the control arithmetic unit 23 A circuit 26 and a cutoff circuit 27 connected between the motor drive circuit 24 and the three-phase brushless motor 12. It is equipped with a.

  As shown in FIG. 2, the motor drive circuit 24 includes a series circuit in which two field effect transistors Qua and Qub are connected in series, and two field effect transistors Qva and Qva connected in parallel with the series circuit. The inverter circuit includes a series circuit of Qvb and a series circuit of field effect transistors Qwa and Qwb. The connection point of the field effect transistors Qua and Qub, the connection point of the field effect transistors Qva and Qvb, and the connection point of the field effect transistors Qwa and Qwb of this inverter circuit are connected to each star-connected exciting coil of the three-phase brushless motor 12. The

  Further, the FET gate drive circuit 26 controls each field effect transistor of the motor drive circuit 24 with duty ratios Du, Dv, and Dt determined based on current command values Iut, Ivt, and Iwt output from a control arithmetic unit 23 described later. It is turned ON / OFF by a PWM (pulse width modulation) signal of Dw, and thereby the magnitudes of currents Imu, Imv and Imw that actually flow through the three-phase brushless motor 12 are controlled.

  The interrupting circuit 27 is individually inserted between each phase coil of the three-phase brushless motor 12 and the connection point of the field effect transistors Qua, Qub, Qva, Qvb and Qwa, Qwb of the motor drive circuit 24. In addition, it is composed of normally open relay circuits RLY1, RLY2, and RLY3. The relay circuits RLY1 to RLY3 are for electrically disconnecting the connection between the three-phase brushless motor 12 and the motor drive circuit 24, and the steering assist control process by the electric power steering control device is not activated. Sometimes, when the steering wheel 1 is rotated in a state where the three-phase brushless motor 12 and the motor drive circuit 24 are electrically connected, the three-phase brushless motor is cut off between the three-phase brushless motor 12 and the motor drive circuit 24. A phenomenon in which the steering wheel is locked by avoiding a current flowing between the motor 12 and the motor drive circuit 24 is avoided. In addition, when the electric power steering control device is operated, the three-phase brushless motor 12 and the motor drive circuit 24 are controlled to be in a conductive state, thereby enabling power supply to the three-phase brushless motor 12. During the operation of the electric power steering control device, the current value supplied to the actual three-phase brushless motor 12 based on the abnormality of each field effect transistor constituting the motor drive circuit 24 and the detection result of the motor current detection circuit 26. When an abnormality or the like is detected, the three-phase brushless motor 12 and the motor drive circuit 24 are disconnected to prevent the three-phase brushless motor 12 from malfunctioning.

The control arithmetic unit 23 executes a known steering assist control process based on the torque detection value T, the vehicle speed detection value V detected by the torque sensor 3, the motor current detection values Iud and Iwd, and the rotor rotation angle θ. Then, a pulse width variable (PWM) signal for generating the steering assist force according to the torque detection value T and the vehicle speed detection value V by the three-phase brushless motor 12 is formed, and these are output to the FET gate drive circuit 26. For example, the steering assist command value I _M ^* for generating the steering assist force according to the torque detection value T and the vehicle speed detection value V by the three-phase brushless motor 12 is calculated by a known procedure and detected by the motor current detection circuit 22. The phase current Ivd is calculated based on the detected motor current values Iud and Iwd which are the phase currents of the V phase and the W phase, and the three-phase brushless motor 12 is calculated based on the steering assist command value I _M ^* and the rotor rotation angle θ. Three-phase phase separation processing for converting the target phase current values Iud ^* , Ivd ^*, and Iwd ^* of the U phase, V phase, and W phase, and the motor current detection values Iud and Iwd detected by the motor current detection circuit 22 and Ivd calculated based on the target phase current Iud ^*, Ivd ^* and Iwd ^* current command value by performing a PID process to deviation between based on Iut, current feedback processing for calculating the Ivt and Iwt Was carried out, the calculated phase current command value Iut, to form a pulse width variable (PWM) signal corresponding to the Ivt and Iwt.

  Further, when operating the three-phase brushless motor 12 in accordance with the steering assist control process, the control arithmetic unit 23 controls the relay circuits RLY1 to RLY3 of the cutoff circuit 27 to be in a conductive state. A relay control signal is output, and it is confirmed whether or not each of the relay circuits RLY1 to RLY3 is actually in a conduction state. When a conduction abnormality is detected, for example, an alarm device 30 provided near the driver's seat is activated. Notification of continuity abnormality is made by voice or lighting of the lamp.

  Further, after the steering assist control process is completed, a relay control signal for controlling the relay circuits RLY1 to RLY3 of the cutoff circuit 27 to be in an open state is output. In addition, during execution of the steering assist control process, abnormality monitoring of each part of the system of the electric power steering control device is performed by known procedures based on various signals such as motor current detection values Iud and Iwd detected by the motor current detection circuit 22. When the abnormality is detected, the steering assist control process is stopped, and the cutoff circuit 27 is controlled to be opened, and the connection between the motor drive circuit 24 and the three-phase brushless motor 12 is cut off.

FIG. 3 shows the configuration of the relay circuits RLY1 to RLY3 constituting the blocking circuit 27. As shown in FIG.
Since the relay circuits RLY1 to RLY3 have the same configuration, the relay circuits RLY1 to RLY3 will be described here as the relay circuit RLY.
As shown in FIG. 3, the relay circuit RLY has a bidirectional contact structure with a neutral position having one movable contact tm and two fixed contacts t1 and t2. For example, the excitation coil and the excitation coil It is comprised by the mechanical relay which has a mechanical contact, such as a relay circuit provided with the movable piece controlled by. The terminal (first coupling point) k1 of the relay circuit RLY that is connected to the motor drive circuit 24 and the movable contact tm are connected, and the relay circuit RLY is connected to the three-phase brushless motor 12 of the relay circuit RLY. The fixed contacts t1 and t2 are connected to the terminal (second coupling point) k2 on the side. That is, the relay circuit RLY can be controlled to be in a conductive state regardless of which of the fixed contact t1 and the fixed contact t2 is connected to the movable contact tm.

  When the control is not performed, the movable contact tm is neutral and the relay circuit RLY is opened (third state). During the control, the fixed contact t1 or the fixed contact t2 and the movable contact tm are controlled to be conductive. One terminal k1 of the relay circuit RLY in a state where the movable contact tm and the fixed contact t1 are conducted (first state) or in a state where the movable contact tm and the fixed contact t2 are conducted (second state). And the other terminal k2.

Next, the operation of the first embodiment will be described.
FIG. 4 is a flowchart showing an example of the processing procedure of the relay control processing when the blocking circuit 27 executed by the control arithmetic device 23 is controlled to be in a conductive state.
In the control arithmetic unit 23, for example, the relay control process is executed at a preset timing such as when the electric power steering control device is activated, and the cutoff circuit 27 is controlled to be in a conductive state.

First, in step S1, a relay control signal for controlling the movable contact tm and the fixed contact t1 of the relay circuits RLY1 to RLY3 to be in a conductive state for controlling the relay circuits RLY1 to RLY3 of the cutoff circuit 27 to be in a conductive state. Is output.
Next, the process proceeds to step S2, and continuity confirmation processing for confirming whether or not each of the relay circuits RLY1 to RLY3 is in a continuity state is performed.

  This continuity confirmation process may be performed by a known procedure. For example, the motor drive circuit 24 is driven and controlled so as to supply current to the extent that the three-phase brushless motor 12 does not rotate, and the motor detected by the motor current detection circuit 22. Based on the current detection values Iud and Iwd, it is detected whether a phase current flows in each phase, or the voltages at both ends of the relay circuits RLY1 to RLY3 are detected to detect whether they are equivalent. As a result, the conduction state is confirmed.

If it is confirmed as a result of this continuity confirmation processing that each of the relay circuits RLY1 to RLY3 is in a continuity state, the interruption circuit 27 is regarded as normal, and the processing is terminated as is from step S3.
And after starting each part which comprises an electric power steering control device and performing predetermined | prescribed initial setting, the above-mentioned steering assist control process is started, and the said motor drive circuit 24 is controlled based on the detection signal of various sensors. The three-phase brushless motor 12 is driven and controlled to generate a steering assist force according to the torque detection value T and the vehicle speed detection value V.

  On the other hand, when it is detected as a result of the continuity check process that any of the relay circuits RLY1 to RLY3 is not in the continuity state, for example, foreign matter such as dust and dirt is mixed between the movable contact tm and the fixed contact t1. If the relay circuits RLY1 to RLY3 are not in a conductive state due to the contact being oxidized or an insulating film being formed, etc., the process proceeds from step S3 to step S4, and this time, the movable contact tm A relay control signal for controlling the fixed contact t2 to be in a conductive state is output.

The connection destination of the movable contact tm may be switched only for the relay circuit in which the continuity abnormality is detected, or the connection destination may be switched for all the relay circuits RLY1 to RLY3.
Then, it transfers to step S5 and performs the conduction | electrical_connection confirmation process for confirming whether the movable contact tm and the stationary contact t2 became the conduction | electrical_connection state. This conduction confirmation process may be performed in the same manner as the conduction confirmation process in step S2.

Next, the process proceeds to step S6, and if it is confirmed that the movable contact tm and the fixed contact t2 of each of the relay circuits RLY1 to RLY3 are in the conduction state as a result of the conduction confirmation process in step S5, the process proceeds to step S7. To do.
Here, at this time, the movable contact tm and the fixed contact t1 are not in a conductive state, but the movable contact tm and the fixed contact t2 are in a conductive state, so that the electric power from the motor drive circuit 24 to the three-phase brushless motor 12 The supply is possible, that is, it can be operated as a system of an electric power steering control device. For this reason, in step S7, the notification of the continuity abnormality is not performed, and only the fact that the continuity abnormality has occurred between the movable contact tm and the fixed contact t1 is stored in the predetermined storage area, and the process is ended as it is. That is, power is supplied through a path that passes through the movable contact tm and the fixed contact t2 where no conduction abnormality has occurred.

And after starting each part which comprises an electric power steering control device and performing predetermined initial setting processing, the above-mentioned steering auxiliary control processing is started, and steering auxiliary power according to torque detection value T and vehicle speed detection value V is given. generate.
On the other hand, when it is not confirmed in step S6 that the movable contact tm and the fixed contact t2 are in the conductive state in each of the relay circuits RLY1 to RLY3, the process proceeds to step S8, and both the fixed contacts t1 and t2 are movable. Since the contact with the contact tm is not conducted and the interruption circuit 27 is not conducted, the alarm device 30 for notifying the abnormality of the interruption circuit 27 is activated to notify the interruption circuit 27 that the conduction abnormality has occurred. . Then, the process ends. In this case, even if the steering assist control process is performed, the steering assist control process is not performed because the three-phase brushless motor 12 cannot be driven.

Here, in a relay circuit having a mechanical contact, even if the relay circuit is controlled to be in a conductive state due to oxidation of the contact or foreign matter such as dust mixed between the relay contacts, the relay circuit is actually in a conductive state. It may not be possible.
However, as described above, when there is a continuity abnormality between the movable contact tm and the fixed contact t1, the fixed contact t2 and the movable contact tm are controlled to be in a conductive state instead of the fixed contact t1, and this fixed contact. Since power is supplied to the three-phase brushless motor 12 via t2 and the movable contact tm, even if foreign matter is mixed between the relay contacts of the fixed contact t1, the relay of the fixed contact t2 If no foreign matter is mixed between the contacts, power can be supplied to the three-phase brushless motor 12 via the fixed contact t2, and steering assist control processing can be performed. Therefore, it is possible to prevent the system from becoming inoperable due to foreign matters mixed in though the system itself of the electric power steering control device has no abnormality.

  In particular, in a relay circuit having a bidirectional contact structure having two fixed contacts, it is rare that foreign matter or the like is mixed between the relay contacts of the fixed contact t1 and the fixed contact t2. By configuring so as to supply power via one of the two paths via t2, it is possible to effectively prevent the system from becoming inoperable.

  In addition, even when a conduction abnormality with the fixed contact t1 is detected as described above, if the conduction with the fixed contact t2 is normal, the steering assist control process is executed without determining that the conduction abnormality has occurred. Thus, the driver cannot recognize that the continuity abnormality has occurred in the cutoff circuit 27, but stores the fact that the continuity abnormality has occurred in a predetermined storage area as described above. From this, by referring to the occurrence information of the continuity abnormality stored in the predetermined storage area, the driver can recognize that the continuity abnormality has occurred, while suppressing the occurrence of the system down, and , It is possible to respond quickly to abnormal conduction.

In addition, even when the movable contact tm and the fixed contacts t1 and t2 are connected, the electrical characteristics between the terminals k1 and k2 of the relay circuit RLY do not change, so the fixed contacts t1 and t2 are switched. Even so, the electrical characteristics of the relay circuit RLY do not change.
In the first embodiment, the relay circuit RLY1 to RLY3 has been described using a relay having a bidirectional contact structure with a neutral position. However, the present invention is not limited to this. When a relay circuit RLY is configured by connecting a plurality of relay circuits having a structure in parallel, and only one of these relay circuits is controlled to be in a conducting state, and the relay circuit RLY is conducted, and this conduction abnormality occurs Alternatively, another relay circuit may be turned on, and a relay circuit that can be turned on among a plurality of relay circuits connected in parallel may be turned on. By configuring the relay circuit RLY using a plurality of relay circuits in this way, it is possible to reduce the possibility of all relay circuits becoming abnormal in conduction, that is, the interruption circuit 27 becomes abnormal in conduction and the system is down. It is possible to reduce the possibility of becoming effective.

In the first embodiment, the movable contact tm and the fixed contact t1 are first connected, and the connection destination of the movable contact tm is switched to the fixed contact t2 when a conduction abnormality is detected. However, the present invention is not limited to this, the fixed contact t2 may be connected first, and the fixed contact to be connected first may be alternated between the fixed contact t1 and the fixed contact t2.
Here, in the first embodiment, the three-phase brushless motor 12 corresponds to the electric motor, the steering assist control device 20 corresponds to the motor drive control means, and each of the relay circuits RLY1 to RLY3 of the cutoff circuit 27 is powered. Corresponding to the supply relay circuit, the relay control processing of FIG. 4 corresponds to the relay circuit control means, and the processing of step S2 and step S4 of FIG. 4 corresponds to the conduction abnormality detection means.

Next, a second embodiment of the present invention will be described.
The second embodiment is the same as the first embodiment except that the interruption circuit 27 and the relay control processing procedure for the interruption circuit 27 are different. Detailed description thereof will be omitted.
FIG. 5 shows the configuration of the relay circuits RLY1 to RLY3 of the cutoff circuit 27 in the second embodiment.

  As shown in FIG. 5, the relay circuit RLY in the second embodiment includes a switching relay 101 having a c-contact structure, and is normally connected in series to one fixed contact t11 of the switching relay 101 and has a mechanical contact. And an open / closed relay 102. The fixed contact t13 of the switching relay 102 and the other fixed contact t12 of the switching relay 101 are connected to a terminal k2 on the side connected to the three-phase brushless motor 12 of the relay circuit RLY. The movable contact tm1 is connected to the terminal k1 on the side connected to the motor drive circuit 24 of the relay circuit RLY.

  In the switching relay 101, the fixed contact t11 is a normally closed contact and the fixed contact t12 is a normally open contact. When not controlled, the movable contact tm1 and the fixed contact t11 are in a conductive state, and the open / close relay 102 is maintained in an open state. Thus, the terminals k1 and k2 of the relay circuit RLY are disconnected (third state). By controlling the open / close relay 102 from this state to the conductive state, power is supplied via the switching relay 101 and the open / close relay 102 (first state). In addition, when the switching relay 101 is controlled, the movable contact tm1 and the fixed contact t12 of the switching relay 101 are in a conductive state, and a short circuit path (short circuit means) is formed to connect between the terminals k1 and k2 of the relay circuit RLY. (Second state), power is supplied through this short-circuit path.

Next, the operation of the second embodiment will be described.
FIG. 6 is a flowchart illustrating an example of a processing procedure of relay control processing executed in the control arithmetic device 23 in the second embodiment.
In the control arithmetic unit 23, relay control processing is executed at a preset timing. First, in step S11, the relay circuits RLY1 to RLY3 are controlled to be in a conductive state, so that the open / close relay 102 is controlled to be in a conductive state. Output relay control signal.

  Next, the process proceeds to step S12, and a continuity confirmation process for detecting whether or not the open / close relay 102 is in a conductive state is performed according to the same procedure as in the first embodiment. If it is confirmed that the relay 102 is in the conductive state, the relay circuits RLY1 to RLY3 are in the conductive state and the cutoff circuit 27 is normal, and the process ends from step S13.

And after performing a predetermined process, a steering assist control process is started and the steering assist force according to the torque detection value T and the vehicle speed detection value V is generated.
On the other hand, if it is detected as a result of the continuity confirmation process that the open / close relay 102 of any of the relay circuits RLY1 to RLY3 is not in the continuity state, the process proceeds from step S13 to step S14. A relay control signal for switching the connection destination of the movable contact tm1 is output. That is, the connection destination of the movable contact tm1 is switched from the fixed contact t11 to the fixed contact t12.

The connection destination of the movable contact tm1 of the switching relay 101 may be switched only for the relay circuit in which the conduction abnormality is detected, or the connection destination may be switched for all the relay circuits RLY1 to RLY3. Good.
Then, the process proceeds to step S15, and the conduction confirmation process for confirming whether or not the movable contact tm1 and the fixed contact t12 are in the conduction state is performed in the same manner as described above, and then the process proceeds to step S16. As a result of the conduction confirmation process, if it is confirmed that each of the relay circuits RLY1 to RLY3 is in the conduction state, the process proceeds to step S17.

  Here, in this state, the open / close relay 102 is not in the conductive state, but in the switching relay 101, the movable contact tm1 and the fixed contact t12 are in the conductive state, and a short-circuit path is formed between the terminals k1 and k2 of the relay circuit RLY. The power supply from the motor drive circuit 24 to the three-phase brushless motor 12 is possible through this short-circuit path. That is, it can be operated as a system of the electric power steering control device. For this reason, in step S17, only the fact that the continuity abnormality has occurred in the open / close relay 102 is stored in a predetermined storage area, and the processing is ended as it is.

And after performing a predetermined process, a steering assist control process is started and the steering assist force according to the torque detection value T and the vehicle speed detection value V is generated.
On the other hand, when it is not confirmed in step S16 that each of the relay circuits RLY1 to RLY3 is in a conductive state, the process proceeds to step S18, where the open / close relay 102 is not in a conductive state and a short circuit path is not formed. Since the relay circuits RLY1 to RLY3 are not in the conductive state, the interruption circuit 27 is determined not to be in the conductive state and is determined to be abnormal, and the alarm device 30 is activated to cause the abnormality in the interruption circuit 27. Notice. Even if the steering assist control process is performed in this state, the steering assist control process is not performed because the three-phase brushless motor 12 cannot be driven.

Thus, in the second embodiment, when the open / close relay 102 is abnormally connected, the short circuit path that short-circuits the terminals t1 and t2 of the relay circuit RLY by switching the connection destination of the switching relay 101. In this case, the same effect as that of the first embodiment can be obtained.
In the second embodiment, since the relay circuit RLY is configured by combining different circuits of the switching relay 101 and the open / close relay 102, an insulating film is formed at the relay contact, etc. Therefore, there is a low possibility that both the switching relay 101 and the open / close relay 102 will not be able to conduct. Therefore, it is possible to reduce the possibility of a situation in which the open / close relay 102 becomes abnormal in conduction and the switching relay 101 cannot be switched. Therefore, it is possible to reduce the possibility that the electric power steering control device will be down.

Also in this case, the electrical characteristics between the terminals k1 and k2 are different between when the terminals k1 and k2 of the relay circuit RLY are conducted through the open / close relay 102 and when they are conducted by forming a short circuit path. Therefore, even when the switching relay 101 is switched, the electrical characteristics of the relay circuit RLY do not change.
In the second embodiment, the case where one short-circuit path is formed by using a switching relay having a c-contact structure has been described. For example, a switching relay having three or more fixed contacts is used, and a plurality of switching relays are used. A short circuit path may be formed. By configuring a plurality of short-circuit paths in this way, it is possible to reduce the possibility that all the fixed contacts of the switching relay cannot be connected to the movable contacts, so that the relay circuit RLY may become abnormally connected. It is possible to reduce the property and is effective.

In addition, the switching relay 101 is configured by connecting, for example, a plurality of relay circuits having an a-contact structure in parallel, and any one of the relay circuits connected in parallel is brought into a conductive state, so that the switching relay 102 is short-circuited. It is also possible to switch between routes.
In the second embodiment, the case has been described in which the terminals k1 and k2 of the relay circuit RLY are first conducted through the open / close relay 102, and the switching relay 101 is switched when an abnormality occurs. However, the present invention is not limited to this, and the switching relay 101 may be made to conduct first through the switching short-circuit path, and the path to be conducted first is alternately changed between the path via the open / close relay 102 and the short-circuit path. You may do it.
Here, in the second embodiment, the switching relay 102 corresponds to the switching means, the switching relay circuit 101 corresponds to the switching means, and the relay control processing of FIG. 6 corresponds to the relay circuit control means. Steps S12 and S15 correspond to the conduction abnormality detection means.

Next, a third embodiment of the present invention will be described.
In the third embodiment, as shown in FIG. 7, in the first embodiment, the relay circuits RLY1 to RLY3 of the cutoff circuit 27 have mechanical contacts as shown in FIG. The relay 201 includes an electrical relay 202 having an electrical contact connected in parallel with the mechanical relay 201.

  The mechanical relay 201 is constituted by, for example, a relay circuit having a normally open mechanical contact having an a contact structure. The electrical relay 202 is an electrical device having no mechanical contact such as a switch circuit composed of a semiconductor switching element such as a transistor or a non-contact relay composed of an optical semiconductor such as a semiconductor switching element and a photocoupler. It consists of a simple relay circuit. When both the mechanical relay 201 and the electrical relay 202 are in an open state, the terminals k1 and k2 of the relay circuit RLY are disconnected (third state), and only the mechanical relay 201 is controlled to be in a conductive state (first state) State) and when only the electrical relay 202 is controlled to be in a conducting state (second state), the terminals k1 and k2 of the relay circuit RLY are conducted.

In the control arithmetic unit 23, the relay control process shown in FIG. 8 is executed at a predetermined timing as in the first embodiment.
Specifically, first, in step S21, relay control signals for controlling the mechanical relays 201 of the relay circuits RLY1 to RLY3 to be in a conductive state are output to the cutoff circuit 27.

  Next, the process proceeds to step S22, and a conduction confirmation process for detecting whether or not each of the relay circuits RLY1 to RLY3 is in a conduction state is performed in the same procedure as described above, and each of the relay circuits RLY1 to RLY3 is in a conduction state. If it is confirmed that the interruption circuit 27 is normal, the process ends from step S23 as it is, and after performing a predetermined initial stage, the steering assist control process is started.

  On the other hand, if it is detected as a result of the continuity check process that any one of the relay circuits RLY1 to RLY3 is not in the continuity state, that is, if it is detected that the mechanical relay 201 is abnormal in continuity, steps S23 to S23 are performed. The process proceeds to S24, and this time, instead of the mechanical relay 201, a relay control signal for controlling the electrical relay 202 to the conductive state is output.

The control of the electrical relay 202 may be performed only for the relay circuit in which the continuity abnormality has occurred, or may be switched in all the relay circuits RLY1 to RLY3.
Subsequently, the process proceeds to step S25, and a continuity confirmation process for detecting whether or not the electrical relay 202 is in a continuity state is performed in the same procedure as described above. As a result of the continuity confirmation process, the relay circuits RLY1 to RLY3 are in a continuity state. If it is confirmed that the process has been completed, the process proceeds from step S26 to step S27. After storing the fact that an abnormality has occurred in the mechanical relay 201 in a predetermined storage area, the process is terminated and the predetermined process is performed. Then, the steering assist control process is started.

  On the other hand, when it is not confirmed in step S26 that each of the relay circuits RLY1 to RLY3 is in the conductive state, the process proceeds to step S28, and the mechanical relay 201 and the electrical relay 202 are not in the conductive state, and the relay circuit RLY1. ~ RLY3, that is, it is determined that there is an abnormality because the cutoff circuit 27 is not in a conductive state, the alarm device 30 is activated, the cutoff circuit 27 is notified that a conduction abnormality has occurred, and the steering assist control process is not performed.

Therefore, in this case as well, the same operational effects as those of the above embodiments can be obtained.
In the third embodiment, the mechanical relay 201 and the electrical relay 202 are used in parallel as described above.
Here, when a mechanical relay is used instead of an electrical relay as a relay circuit connected in parallel with the mechanical relay 201, a relay of the same lot manufactured at the same time is often used as the electrical relay. In this case, for example, when the oxide film is generated at the contact and the conduction is not possible, it is predicted that these mechanical relays are equivalent, so even if the mechanical relays are connected in parallel, one of the electrical relays is abnormally connected. At the same time, the other electrical relay may also become abnormal in conduction.

As described above, by connecting the electrical relay 202 in parallel to the mechanical relay 201, the timing at which these relays cannot be conducted can be shifted, and the possibility that the interruption circuit 27 becomes abnormal in conduction is reduced. can do.
In addition, since the electrical relay 202 that is relatively less likely to be contaminated with foreign matter, which is the cause of the occurrence of a continuity abnormality, is used for the mechanical relay 201 that may be unable to conduct due to foreign matter or the like. In addition, the possibility that both the electrical relay 202 and the electrical relay 202 cannot be conducted can be reduced.

  Also in this case, the electrical characteristics between the terminals k1 and k2 are different between the case where the terminals k1 and k2 of the relay circuit RLY are conducted via the mechanical relay 201 and the case where the terminals k1 and k2 are conducted via the electrical relay 202. Therefore, the electrical characteristics of the relay circuit RLY do not change between when the mechanical relay 201 is turned on and when the electrical relay 202 is turned on.

In this case as well, the mechanical relay 201 is turned on first, but the electrical relay 202 may be turned on first, and the relays that are turned on first are the mechanical relay 201 and the electrical relay 202. You may make it change alternately.
Here, the mechanical relay 201 corresponds to the first opening / closing means, the electrical relay 202 corresponds to the second opening / closing means, the relay control processing in FIG. 8 corresponds to the relay circuit control means, and step S22 in FIG. The process of step S25 corresponds to the conduction abnormality detection means.

  In the first to third embodiments, the case where the present invention is applied to the blocking circuit 27 interposed between the motor driving circuit 24 and the three-phase brushless motor 12 has been described. However, the present invention is not limited to this. Instead, for example, the present invention can be applied to a relay circuit that is interposed between a battery (not shown) and the motor drive circuit 24 and that cuts off the power supply to the motor drive circuit 24.

Next, a fourth embodiment of the present invention will be described.
In the fourth embodiment, the relay circuits RLY1 to RLY3 of the cutoff circuit 27 are configured by connecting a mechanical relay 201 and an electrical relay 202 in parallel as shown in FIG. When conducting control of RLY, both the mechanical relay 201 and the electrical relay 202 are turned on.

The control arithmetic device 23 executes the relay control process shown in FIG. 9 at a predetermined timing. First, in step S31, the mechanical relay 201 and the electrical relay 202 are turned on to control the relay circuits RLY1 to RLY3 to be in a conductive state. Both output relay control signals for controlling to a conductive state.
Next, the process proceeds to step S32, and first, continuity confirmation processing is performed to determine whether or not the electrical relay 202 is in a continuity state. This conduction confirmation process may be performed in the same manner as described above. In addition, when a small amount of current is supplied and the conduction check is performed using the motor current detection values Ivd and Iwd detected by the motor current detection circuit 22, it may be performed before the mechanical relay 201 is switched to the conduction state. .

  Next, the process proceeds to step S33, and if it is determined that the electrical relay 202 is in the conductive state, the process proceeds to step S34, and the relay control signal is output from the time when the relay control signal is output to the mechanical relay 201 in step S31. When the predetermined time that can be considered that the mechanical relay 201 is switched to the conductive state has elapsed, the process proceeds to step S35, and a continuity confirmation process is performed to check whether the mechanical relay 201 is switched to the conductive state. Do. This conduction confirmation process may be performed, for example, by detecting a current flowing through wiring on the mechanical relay 201 side connected in parallel with the electrical relay 202.

  Next, the process proceeds to step S36, and if it is confirmed that the mechanical relay 201 is in the conductive state as a result of the conduction check in step S35, the cutoff circuit 27 is determined to be normal, and the process proceeds from step S36 to step S37. It is determined that the normal assist is possible by the control process, and the determination result of the normal assist permission is stored in a predetermined storage area as the assist type determination result. That is, the execution of the steering assist control process for applying the steering assist force according to the torque detection value T and the vehicle speed detection value V is instructed. Then, the process ends.

On the other hand, if it is determined as a result of the conduction check in step S35 that the conduction is abnormal, the process proceeds from step S36 to step S44 described later.
On the other hand, if it is determined as a result of the conduction check of the electrical relay 202 in step S32 that the conduction abnormality is detected, the process proceeds from step S33 to step S41. The processes in step S41, step S42, and step S43 are the same as the processes in step S34, step S35, and step S36. If the continuity of the mechanical relay 201 is confirmed to be abnormal, that is, if both the mechanical relay 201 and the electrical relay 202 are abnormal in continuity, the process proceeds to step S45, and the process of step S8 in FIG. In the same procedure, the alarm device 30 is activated to notify the driver that the cutoff circuit 27 is abnormally connected.

  On the other hand, as a result of confirming the continuity of the mechanical relay 201 in step S42, when it is determined that it is in a conductive state, that is, when it is determined that the electrical relay 202 is abnormal in continuity but the mechanical relay 201 is normal. The process proceeds from step S43 to step S44. When it is determined in step S35 that the continuity is abnormal, that is, the electrical relay 201 is in the conductive state, the mechanical relay 202 is also determined to be abnormal in continuity, and the process proceeds from step S36 to step S44.

  Here, at the time of step S44, only one of the mechanical relay 201 and the electrical relay 202 is in a conductive state. That is, normally, power is supplied through both the mechanical relay 201 and the electrical relay 202, whereas power is supplied through only one of the relays. For this reason, depending on the specifications such as the allowable input voltage and allowable input current of the mechanical relay 201 or the electrical relay 202, there is a possibility that sufficient power cannot be supplied to the three-phase brushless motor 12. For this reason, since it is necessary to limit the power supply amount in consideration of the specifications of the electrical relay 201 and the mechanical relay 202, the normal assist is not permitted, and the determination result indicating that the assist limitation is necessary is used as the assist type determination result. Store in a predetermined storage area (step S44). Then, the process ends. That is, instead of the normal steering assist control process for applying the steering assist force according to the torque detection value T and the vehicle speed detection value V, the three-phase brushless motor 12 is supplied according to the specifications of the mechanical relay 201 and the electrical relay 202. Is instructed to execute the steering assist control process when the assist is limited.

  After performing the relay control process in this way, when the predetermined process is performed and the timing for executing the steering assist control process is reached, in the fourth embodiment, the steering control start process shown in FIG. In the relay control process of FIG. 9, the assist type determination result stored in the predetermined storage area in the process of step S37 or step S44 is referred to and it is determined whether or not the normal assist is permitted. When the normal assist permission is performed, the process proceeds from step S51 to step S52, and the normal steering control process for generating the steering assist force according to the torque detection value T and the vehicle speed detection value V is started. . Then, the process ends.

  On the other hand, if the normal assist permission is not performed, the process proceeds from step S51 to step S53, where it is determined whether assist limitation is necessary. When it is determined that assist limitation is necessary, the process proceeds to step S54. A steering control process at the time of assist limitation is started in order to drive and control the three-phase brushless motor 12 by limiting the amount of power supplied to the phase brushless motor 12. Then, the process ends. If neither assist permission nor assist limitation is necessary, the steering circuit 27 terminates the process without starting any steering assist control process as a conduction abnormality of the cutoff circuit 27.

  As described above, in the fourth embodiment, since the mechanical relay 201 and the electrical relay 202 are used in combination, if one of the relays becomes abnormal in conduction, Supply can be made. Therefore, although the assist limitation in the steering assist control process is performed, the possibility of the system being down can be reduced.

  In addition, as described above, since the mechanical relay 201 and the electrical relay 202 are used in combination as the relay circuits RLY1 to RLY3 and different types of relay circuits are used, both of them cannot conduct, and the cutoff circuit 27 is It is possible to reduce the possibility of a system malfunction due to conduction abnormality. In addition, since the amount of current supplied to the three-phase brushless motor 12 may be shared by the mechanical relay 201 and the electrical relay 202, each allowable input current is small compared to the case where the relay circuit is configured by one relay circuit. Good.

Therefore, since it is not necessary to use a relay circuit for a large input current for both the mechanical relay 201 and the electrical relay 202, it can be realized by a relatively inexpensive relay circuit for a small input current, and the cost can be reduced. .
In the fourth embodiment, the case where the mechanical relay 201 and the electrical relay 202 are used together has been described. For example, different types of mechanical relays or different types of electrical relays are used together. Thus, the relay circuits RLY1 to RLY3 can be configured.

In addition, when either one of the mechanical relay 201 and the electrical relay 202 becomes abnormal in conduction, only assist limitation is performed. In this case as well, the mechanical relay 201 or the electrical relay is performed as in the above embodiments. It may be stored in a predetermined storage area that any one of 202 is abnormally connected.
Here, in the fourth embodiment, the mechanical relay 201 corresponds to the first opening / closing means, the electrical relay 202 corresponds to the second opening / closing means, and the relay control processing of FIG. Correspondingly, the processing of steps S32, S34 and S35 in FIG. 9 corresponds to the conduction abnormality detecting means, and the processing of step S44 corresponds to the control amount limiting means.

  In each of the embodiments described above, the motor current detection circuit 22 has been described with respect to the case where the phase currents of two phases are detected. can do. Further, the present invention is not limited to the three-phase brushless motor 12, and can be applied to other types of electric motors such as a single phase or three or more phases, and the motor control method is a control method other than the above. It can be applied even if it exists.

It is a schematic block diagram which shows an example of the electric power steering control apparatus to which this invention is applied. It is a block diagram which shows the specific structure of the steering auxiliary control apparatus of FIG. FIG. 3 is a circuit diagram of a relay circuit RLY in the first embodiment of the present invention. 6 is a flowchart illustrating an example of a processing procedure of relay control processing executed by the control arithmetic device in the first embodiment. It is a circuit diagram of the relay circuit RLY in the 2nd Embodiment of this invention. It is a flowchart which shows an example of the process sequence of the relay control process in 2nd Embodiment. It is a circuit diagram of the relay circuit RLY in the 3rd Embodiment of this invention. It is a flowchart which shows an example of the process sequence of the relay control process in 3rd Embodiment. It is a flowchart which shows an example of the process sequence of the relay control process in the 4th Embodiment of this invention. In 4th Embodiment, it is a flowchart which shows an example of the process sequence of the steering control starting process performed with a control arithmetic unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3 Torque sensor 8 Steering gear 10 Steering assist mechanism 11 Reduction gear 12 Three-phase brushless motor 13 Rotor position detection circuit 20 Steering assist control device 21 Vehicle speed sensor 22 Motor current detection circuit 23 Control arithmetic device 24 Motor drive circuit 26 FET gate drive circuit 27 Interrupt circuit 30 Alarm device 101 Switching relay 102 Open / close relay 201 Mechanical relay 202 Electrical relays RLY1 to RLY3 Relay circuit

Claims (13)

A relay circuit interposed between the first circuit and the second circuit and capable of conducting and blocking between them;
A first state of conducting between a first coupling point on the side connected to the first circuit of the relay circuit and a second coupling point on the side connected to the second circuit;
The first coupling point is electrically connected between the first coupling point and the second coupling point, and the wiring between the first coupling point and the second coupling point is the first coupling point in the first state. And a second state in parallel with the wiring between the second coupling points;
A relay circuit capable of realizing a third state in which the wirings in the first state and the wirings in the second state are separated from each other at a position where the wirings are separated from each other.   The relay circuit according to claim 1, wherein the first state, the second state, and the third state are realized by a bidirectional contact structure with a neutral position. Opening and closing means capable of conducting and blocking between the first coupling point and the second coupling point;
Short-circuit means capable of short-circuiting between the first coupling point and the second coupling point;
The first state, the second state, and the third state are switched by a switching unit that interposes either the opening / closing unit or the short-circuit unit between the first coupling point and the second coupling point. The relay circuit according to claim 1, wherein the relay circuit realizes a state. First opening / closing means capable of conducting and blocking between the first coupling point and the second coupling point;
The first state and the second state by the second opening / closing means connected in parallel with the first opening / closing means and capable of conducting and blocking between the first coupling point and the second coupling point. The relay circuit according to claim 1, wherein the third state is realized.   5. The electrical property between the first coupling point and the second coupling point in the first state and the second state is the same, 5. The relay circuit according to item 1.   5. The relay circuit according to claim 4, wherein the first opening / closing means has a mechanical contact, and the second opening / closing means has an electrical contact.   The relay circuit according to any one of claims 1 to 6, wherein a mechanical contact is inserted in the wiring in the first state. An electric motor for applying a steering assist force to the steering system;
Motor drive control means for driving and controlling the electric motor;
A power supply relay circuit comprising the relay circuit according to any one of claims 1 to 7, interposed in a power supply line for driving and controlling the electric motor,
Relay circuit control means for controlling the relay circuit for power supply;
A conduction abnormality detecting means for detecting conduction abnormality of the relay circuit for power supply,
The relay circuit control means switches the power supply relay circuit to the first state when power is supplied to the electric motor;
Electric power steering control, wherein when the continuity abnormality detecting means detects a continuity abnormality of the relay circuit for power supply in the first state, the power supply relay circuit is switched to the second state. apparatus.   9. The continuity abnormality detecting means performs notification as a continuity abnormality of the power supply relay circuit only when the continuity abnormality is detected in both the first state and the second state. The electric power steering control device described. An electric motor for applying a steering assist force to the steering system;
Motor drive control means for driving and controlling the electric motor;
A power supply relay circuit that is inserted into a power supply line for driving and controlling the electric motor and is controlled to be in a conductive state when power is supplied to the electric motor;
Relay circuit control means for controlling the relay circuit for power supply,
The power supply relay circuit includes first opening / closing means capable of conducting and blocking between a first coupling point and a second coupling point connected to the power supply line of the power supply relay circuit; A second opening / closing means connected in parallel with the first opening / closing means and capable of conducting and blocking between the first coupling point and the second coupling point;
The relay circuit control means is an electric power steering control device that controls both the first opening and closing means and the second opening and closing means to conduct when the power is supplied,
Conduction abnormality detection means for individually detecting conduction abnormality of the first opening and closing means and the second opening and closing means;
Limiting the drive control amount of the electric motor by the motor drive control means when the conduction abnormality is detected in only one of the first opening / closing means and the second opening / closing means in the conduction abnormality detection stage. An electric power steering control device comprising: a control amount limiting means.   The conduction abnormality detection means detects each abnormality at a specific timing when a predetermined time that can be considered that the first opening / closing means and the second opening / closing means are actually switched to the conduction state has elapsed. The electric power steering control device according to claim 10.   12. The electric power steering control device according to claim 10, wherein the first opening / closing means has a mechanical contact, and the second opening / closing means has an electrical contact.   The continuity abnormality detecting means notifies the continuity abnormality of the power supply relay circuit only when both the first opening / closing means and the second opening / closing means detect the continuity abnormality. The electric power steering control device according to any one of claims 10 to 12.

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