Motor control device, current control method applied to a motor control device, and electric power steering device using a motor control device

Abstract

A motor control device (10) is provided for controlling a motor (5) equipped with a plurality of winding sets. In this device, when a current control unit (23) detects a short-circuit fault as a primary fault, the current control unit (23) continues the control operation. Furthermore, when the current control unit (23) detects a secondary fault, the current control unit (23) provides control for opening a power supply relay (3). Accordingly, in the event of a fault in one winding of a motor or inverter, torque pulsation is limited, and sufficient output torque is provided. Furthermore, in the event of a secondary fault, excessive heat generation and excessive power consumption are prevented, and the cost of the device is reduced.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The present invention relates to a motor control device for controlling a multi-phase motor having a plurality of winding sets, a current control method applied to a motor control device, and an electric power steering device using a motor control device. 2. Description of related technology

[0002] As a motor control device for controlling a conventional multi-phase motor having a plurality of winding sets, there is a motor control device having a configuration in which a motor includes two winding sets, and the motor control device includes two inverters for controlling currents flowing through the respective winding sets, thereby independently controlling the currents (see, for example, JP 2011-131860 A).

[0003] The motor control device according to JP 2011-131860 A includes power supply relays for electrical connection / disconnection to supply power to respective inverters from a power supply. If a fault occurs on a winding or inverter on one side, the motor control device opens a power supply relay for the side where the fault occurred, thereby interrupting the connection to the power supply. The motor control device also controls the inverter on the normal side (or normal side), thereby continuing to output torque from the motor.

[0004] However, conventional technology has the following problems.

[0005] In the example described in JP 2011-131860 A, a power supply relay connected to a faulty inverter among the plurality of inverters is opened. However, when a short-circuit fault occurs, a closed circuit is formed by a portion of the short-circuit fault and windings, resulting in a circulating current that does not flow through the power supply. This circulating current then generates a torque that acts to slow the rotation of the motor, namely, a braking torque. This braking torque is generated by a current that does not flow through the power supply and cannot be limited by simply opening the power supply relay. Accordingly, a problem of torque deficiency arises.

[0006] Furthermore, an advantage of opening a power supply relay on a faulty side is that it is possible to prevent excessive heat generation and power consumption in the following case. Consider a case where a short-circuit failure of a switching element, a ground fault, or a power supply fault (or power supply short circuit) of a converter or winding occurs. After a power supply relay on a faulty side is opened, in a connection state where the power supply relay on the faulty side is not opened, a secondary failure further occurs in a pair of a winding and an inverter (hereinafter also referred to as a winding drive system) on the faulty side, and the secondary failure is a short-circuit failure of the winding drive system.

[0007] In this case, the positive electric potential and the negative electric potential of the power supply become close to a short circuit across the two locations of the primary fault and the secondary fault, which may lead to a state where excessive current is generated. As a result, excessive heat generation and excessive power consumption may potentially occur. Then, one method for providing an advantage of preventing this condition from occurring is the method of opening the power supply relay on the faulty side when a primary fault occurs, namely the method according to JP 2011-131860 A.

[0008] However, this method requires as many power supply relays as the number of the plurality of winding drive systems, and there is a problem of an increase in the price of the device.

[0009] JP 2007-244028 A discloses a motor controller in which a disconnection can be detected with high precision without compromising control stability. When a state in which a power-on command value corresponding to that phase does not fall within a range corresponding to a threshold for setting a predetermined value and a judgment object range is maintained even though the power supply voltage is appropriate, when a phase current value is below the predetermined value, and the number of revolutions falls within a judgment object range for disconnection, a disconnection detection section judges that a disconnection has occurred.

[0010] WO 2005 / 091488 A1 discloses a motor controller with a current control device for providing a multi-phase voltage command to a drive circuit of an inverter. The current control device includes a normal-time current control means used in a normal mode, an abnormal-time current control means used in an abnormal mode, and an abnormality judgment means. When an abnormality occurs in a phase of a motor or the inverter, a multi-phase voltage command with an abnormal time generated by the current control device with an abnormal time is used as a multi-phase voltage command for the inverter drive circuit.

[0011] WO 2008 / 129658 A1 discloses a control device for an electric motor in which each short-circuit fault point can be located quickly and accurately.The apparatus includes a current control device that sets phase voltage commands in accordance with the currents flowing in the phases of an electric motor and a torque current command; a switching element drive circuit that instructs an inverter to perform switching operations based on the phase voltage commands; the inverter receiving a switching operation signal to drive the electric motor; current detectors arranged in series with the respective switching elements of the phases of the inverter; and short-circuit point locating device that stores a test pattern indicating a predetermined combination for turning on the switching elements of the inverter and locates a short-circuit fault point based on the test pattern and the current detection values ​​of the phases detected by the current detectors in response to the test pattern.

[0012] WO 2007 / 129359 A1 discloses a control device for a multi-phase AC electric motor with an inverter, wherein a current control device comprises an abnormal condition current control means used during any abnormal condition, an abnormal condition determining means that determines any abnormal condition of a wire of an electric motor or a wire of an inverter or a wire connecting the electric motor to the inverter, and an abnormal phase cutting means.The abnormal phase disconnection means disconnects one or more of the abnormal phases determined by the abnormal condition determining means from the circuit, and the abnormal condition current controlling means generates an abnormal condition voltage command in accordance with an abnormal condition determined by the abnormal condition determining means and uses phases other than the disconnected phases of the inverter to perform individual current controls of the phases, wherein the abnormal condition voltage command is used as a multi-phase voltage command. SUMMARY OF THE INVENTION

[0013] The present invention has been made to solve the above-mentioned problems, and therefore has an object to provide a motor control device, a current control method applied to a motor control device, and an electric power steering device using a motor control device, which are capable of preventing excessive heat generation and excessive power consumption, reducing the cost of the device, and restraining or preventing the failure of a winding of a motor or an inverter, such as a short-circuit failure of a switching element, a ground fault of a winding in a phase or a wire connecting an inverter and a winding, a short-circuit fault between two phases, or the like, and further in a case where a secondary fault occurs in a winding drive system on the faulty side.Inhibiting a braking torque generated when the primary fault is a short circuit fault, thereby providing sufficient output torque.

[0014] According to an exemplary embodiment of the present invention, there is provided a motor control device for supplying, from a power supply, and controlling a current flowing through a motor provided with a plurality of winding sets, comprising: a plurality of inverters having a switching element in each of phases of the plurality of winding sets for controlling a voltage applied to each of the phases, thereby controlling a current to be supplied from the power supply to each of the phases of the plurality of winding sets; a power supply relay provided between the power supply and the plurality of inverters for disconnecting an electrical connection;and a current control device for providing, depending on a target value of a torque to be generated by the motor, to each of the plurality of inverters, a voltage command corresponding to the voltage, thereby controlling the current to flow through the plurality of winding sets, wherein: the current control device comprises: a primary fault detecting device for detecting the primary fault of any one of the plurality of winding sets and the plurality of inverters, and a secondary fault detecting device for detecting, after a primary fault is detected, a secondary fault occurring in any one of a winding and an inverter in a system in which the primary fault has occurred;and the current control device is configured to: continue control for an inverter on a normal side when the primary fault detection device detects any one of a short-circuit fault, a ground fault, and a power supply fault fault in any one of the plurality of inverters and a part of the plurality of winding sets as the primary fault; and further to open the power supply relay when the secondary fault detection device detects the secondary fault, the secondary fault being a short-circuit fault in a pair of a winding and an inverter on a faulty side.

[0015] According to an exemplary embodiment of the present invention, there is also provided a current control method applied to a motor control device for supplying, from a power supply, and controlling a current to flow through a motor provided with a plurality of winding sets, the motor control device comprising: a plurality of inverters having a switching element in each of phases of the plurality of winding sets for controlling a voltage to be applied to each of the phases, thereby controlling a current to be supplied from the power supply to each of the phases of the plurality of winding sets; a power supply relay provided between the power supply and the plurality of inverters for disconnecting an electrical connection;and a current control device for providing, depending on a target value of a torque to be generated by the motor, to each of the plurality of inverters, a voltage command corresponding to the voltage, thereby controlling the current to flow through the plurality of winding sets, the current control method comprising: detecting, by the current control device, a primary fault of any one of the plurality of winding sets and the plurality of inverters; and detecting, by the current control device, after a primary fault is detected, a secondary fault occurring in any one of a winding and an inverter in a system in which the primary fault has occurred;and continuing, by the current control means, when any of a short-circuit fault, a ground fault, and a power supply fault fault (or power supply short-circuit fault) is detected in any of the plurality of inverters and a part of the plurality of winding sets upon detecting a primary fault as the primary fault, control for an inverter on a normal side (or normal side); and opening, by the current control means, the power supply relay when the secondary fault is detected, the secondary fault being a short-circuit fault in a pair of a winding and an inverter on a faulty side.

[0016] According to the motor control device, the current control method applied to a motor control device, and the electric power steering device using a motor control device of the present invention, a means for detecting the secondary fault is provided by a fault detection method depending on the primary fault condition. Therefore, it is possible to provide the motor control device, the current control method applied to a motor control device, and the electric power steering device using a motor control device capable of detecting the secondary fault in a case where a fault of a winding of a motor or an inverter, such as a short-circuit fault of a switching element, a ground fault of a winding in a phase or a wire connecting an inverter and a winding, a short-circuit fault between two phases, or the like, occurs.and further, in a case where a secondary fault occurs in a winding drive system on the faulty side, to prevent excessive heat generation and excessive power consumption, reduce the cost of the device, and limit the braking torque generated when the primary fault is a short-circuit fault, thereby providing sufficient output torque. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following is shown in the accompanying drawings. Fig. 1 is a schematic block diagram showing an overall configuration of an engine control apparatus according to a first embodiment of the present invention. Fig. 2 is a configuration diagram of a current control device according to the first embodiment of the present invention. Fig. 3 is a configuration diagram of a disturbance detecting device according to the first embodiment of the present invention. Fig. 4 is a configuration diagram of a fault-time current control device according to the first embodiment of the present invention. Fig. 5 is an explanatory diagram describing a case of generating a braking torque according to the first embodiment of the present invention. Fig. 6 is a flowchart illustrating a sequence of operation related to a phase current excess detection device in a secondary disturbance detection device according to the first embodiment of the present invention. Fig. 7 is a flowchart illustrating a sequence of operation related to a phase current command excess detection device in the secondary disturbance detection device according to the first embodiment of the present invention. Fig. 8 is a flowchart illustrating a sequence of operation related to the secondary circuit open circuit failure detection means in the secondary failure detection means according to the first embodiment of the present invention. Fig. 9 is an explanatory diagram illustrating a state of a current in a case where a primary failure is a short-circuit failure of a switching element on a lower side in a V phase, and a secondary failure is a short-circuit failure of a switching element on an opposite side (upper side) in the same phase, according to the first embodiment of the present invention. Fig. 10 is an explanatory diagram illustrating a state of a current in a case where a primary failure is a short-circuit failure of the switching element on a lower side in a V-phase, and a secondary failure is a short-circuit failure of a switching element on the opposite side (upper side) in another phase (U-phase in this case), according to the first embodiment of the present invention. Fig. 11 is a flowchart illustrating a sequence of processing by the current control device according to the first embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Now, a description will be given of a motor control device, a current control method applied to a motor control device, and an electric power steering device using a motor control device according to preferred embodiments of the present invention with reference to the drawings. First embodiment

[0019] Fig. 1 is a schematic block diagram illustrating an overall configuration of an engine control device according to a first embodiment of the present invention. Note that Fig. 1 illustrates a power supply 4, a motor 5, and a motor rotation angle sensor 6 for detecting a rotation angle of the motor 5 in addition to the motor control device 10.

[0020] The motor 5 includes a first winding set 15 constituted by three phases U1, V1, and W1, and a second winding set 16 constituted by three phases U2, V2, and W2. Then, each of the winding sets 15 and 16 connects the phases in a star connection. These multiple winding sets 15 and 16 form a stator (not shown). The motor 5 is constituted by this stator and a rotor and a rotating shaft fixed to the rotor, which are not shown.

[0021] Note that the following describes an example in which the present invention is applied to a permanent magnet synchronous motor in which each of the winding sets has three phases and permanent magnets are arranged in the rotor. However, the present invention is not limited to this example and can also be applied to motor rotation by driving a multi-phase current with three or more phases.

[0022] The motor control device 10 controls voltages applied to the windings of the motor 5, thereby supplying the motor 5 with electrical power from the power supply 4 and controlling the currents flowing through the windings. Accordingly, the motor control device 10 controls an output torque of the motor 5, which is approximately proportional to the currents.

[0023] Then, the motor control device 10 is constituted by a power supply relay 3, a first inverter 21, a second inverter 22, a current control device 23, a first switching element drive circuit 24, a second switching element drive circuit 25, and a motor rotation angle detection device 26.

[0024] The first inverter 21 is constructed by six switching elements UP1, VP1, WP1, UN1, VN1 and WN1, six diodes DUP1, DVP1, DWP1, DUN1, DVN1 and DWN1 connected in parallel with the respective switching elements, and current detection circuits CT11, CT21 and CT31 for the respective three phases U, V and W.

[0025] Similarly, the second inverter 22 is constructed by six switching elements UP2, VP2, WP2, UN2, VN2 and WN2, six diodes DUP2, DVP2, DWP2, DUN2, DVN2 and DWN2 connected in parallel with the respective switching elements, and current detection circuits CT12, CT22 and CT32 for the respective three phases U, V and W.

[0026] The motor rotation angle detection device 26 in the motor control device 10 receives a signal from the motor rotation angle sensor 6, thereby calculating a rotation angle signal θ of the motor 5. Furthermore, the current control device 23 acquires detection values ​​Iu1dtc, Iv1dtc, Iw1dtc, Iu2dtc, Iv2dtc, and Iw2dtc of phase currents flowing through the respective phases of the motor 5, which are detected by the current detection circuits CT11, CT21, CT31, CT12, CT22, and CT32, respectively.

[0027] Note that in Fig. 1 the values ​​on the first winding side Iu1dtc, Iv1dtc and Iw1dtc are denoted by I1dtc, and the values ​​on the second winding side Iu2dtc, Iv2dtc and Iw2dtc are denoted by I2dtc. In addition, in Fig. 1, the case where the motor rotation angle sensor 6 and the motor rotation angle detecting means 26 are provided is exemplified, but a configuration may be adopted in which the motor rotation angle signal θ is acquired from a motor rotation angle estimated by an estimator.

[0028] As described later, current control means 23 determines phase voltage commands V1* and V2* based on a total torque current command value Iqsum* corresponding to a target motor torque, the phase current detection values ​​I1dtc and I2dtc of the respective phases of the motor 5, and the motor rotation angle signal θ.

[0029] The first switching element drive circuit 24 applies PWM modulation to a first phase voltage command V1*, thereby instructing the first inverter 21 to perform a switching operation. Then, the first inverter 21 receives the switching operation signal, implements chopper control for the switching elements UP1, VP1, WP1, UN1, VN1, and WN1, and causes the currents to flow through the respective phases U1, V1, and W1 of the motor using the electrical power supplied from the power source 4.

[0030] The second switching element drive circuit 25 and the second inverter 22 similarly cause the currents to flow through the respective phases U2, V2, and W2 based on the phase voltage command V2*. Note that the first inverter 21 and the second inverter 22 correspond to the first winding set 15 and the second winding set 16, respectively.

[0031] The one power supply relay 3 is provided between the power supply 4 and the first inverter 21 and second inverter 22 and serves in a switching manner for electrically connecting the power supply 4 and the inverters 21 and 22 to each other and for immediately interrupting the electrical connection.

[0032] Now, a detailed description will be given of an internal configuration of the current control device 23. Fig. 2 is a configuration diagram of the current control device 23 according to the first embodiment of the present invention. Fig. The current control device 23 illustrated in Fig. 2 includes a fault-time current control device 30, a first normal-time current control device 31, a second normal-time current control device 32, a fault detection device 33, a torque current distribution device 35, and four switching devices 36 to 39.

[0033] Here, the first normal-time current control device 31 and the second normal-time current control device 32 are devices for executing a normal control method used in a normal time. On the other hand, the fault-time current control device 30 is a device used when a fault occurs. With this configuration, it is possible to switch the two types of control devices, so that the fault-time current control device 30 can control a pair of the windings and the inverter / the inverter (hereinafter referred to as a winding drive system) on a faulty side among the two systems of the windings and the inverter.

[0034] The total torque current command value Iqsum* is distributed by the torque current distribution device 35 into a first torque current command value Iq01* and a second torque current command value Iq02*, which are command values ​​of torques to be generated by a first winding drive system and a second winding drive system, respectively. According to the first embodiment, the respective command values ​​of the distributed currents are set to half of the total torque current command value Iqsum*. In other words, the setting is configured so that the equivalent torques are generated by the respective systems, and a sum of these provides the output torque.

[0035] In the first system, in a normal time when no disturbance occurs, the first torque current command value Iq01* is set to the first torque current command value Iq1*. Note that when a disturbance occurs, a command shaping device (not shown) may be provided between Iq01* and Iq1*, thereby shaping the first torque current command value Iq1* based on the motor rotation angle signal θ. Similarly, in the second system, the second torque current command value Iq02* is set to the second torque current command value Iq2*.

[0036] Then, the first normal-time current control device 31 outputs a normal-time phase voltage command Vn1* based on the first torque current command value Iq1* and the phase current detection value I1dtc. In the normal time, the switching device 36 selects the normal-time phase voltage command Vn1*, thereby inputting the normal-time phase voltage command Vn1* to the first switching element drive circuit 24 as the first phase voltage command V1*.

[0037] Note that the first normal-time current control means 31 and the second normal-time current control means 32 are configured, for example, as indicated by reference numeral 31a in the block diagram of Fig. 19 illustrated in WO 2005 / 091488 A1, and execute the dq control generally used in the normal time, thereby realizing smooth engine torque generation.

[0038] The first torque current command value Iq1* is used as a q-axis current command in the dq control. Note that in Fig. 2. Lines for inputting the motor rotation angle signal θ to the first normal-time current control means 31 and the second normal-time current control means 32 are not illustrated, but lines may be provided for inputting the coordinate conversion commonly performed in dq control. The q-axis current here is a current component proportional to the torque and is also referred to as a torque current in the description of the first embodiment. Furthermore, the other d-axis current for controlling the field magnet flux is controlled to be zero according to the first embodiment, but a different value may be used.

[0039] On the other hand, in the normal time in the second system, similarly, based on the second torque current command value Iq2*, the dq control is executed by the second normal-time current control means 32, and the normal-time phase voltage command Vn2* is input as a second phase voltage command V2* to the second switching element drive circuit 25.

[0040] In this way, in the normal time, the torque current in the first winding control system and the torque current in the second winding control system are respectively controlled so that these torque currents track the first torque current command value Iq01* and the second torque current command value Iq02*, respectively, resulting in a desired output torque.

[0041] A description will now be given of a disturbance detecting device 33. Fig. 3 is a configuration diagram of the fault detection device 33 according to the first embodiment of the present invention. Fig. The fault detection device 33 illustrated in Figure 3 is constituted by a primary fault detection device 61, a secondary fault detection device 64 and a switching device 65.

[0042] The primary disturbance detection means 61 is a means for detecting a disturbance that occurs first (primarily), namely, a primary disturbance, and the secondary disturbance detection means 64 is a means for detecting a disturbance that occurs secondarily after the occurrence of the first disturbance, namely, a secondary disturbance. First, a description will be given of the primary disturbance detection means 61.

[0043] The primary fault detection device 61 includes a first system fault detection device 62 for detecting a fault in the first winding drive system and a second system fault detection device 63 for detecting a fault in the second winding drive system. The first system fault detection device 62 and the second system fault detection device 63 have the same configuration, and only a description of the first system fault detection device 62 will be given.

[0044] The first system fault detecting means 62 is constituted by an open-circuit fault detecting means for identifying a location of a fault in which a phase is in an open-circuit state, and a short-circuit fault detecting means for identifying a location of a short-circuit fault.

[0045] Although not illustrated, the open-circuit fault detection means and the short-circuit fault detection means may be publicly known methods, and as the open-circuit fault detection means, there is a method as described in JP 2007-244028 A. This method determines, when a power supply voltage and a motor speed are respectively within predetermined ranges, a phase current is equal to or less than a predetermined value, and a phase voltage command is equal to or greater than a predetermined value, that this phase is in a open-circuit fault state.

[0046] Furthermore, the short-circuit fault detection device may be constituted, for example, by an abnormality detection device (27) and a short-circuit location identification device (28) described in WO 2008 / 129658 A1. In this embodiment, when the abnormality detection device determines that a certain abnormality is occurring in an inverter or a motor, the short-circuit location identification device (28) identifies a location of the short-circuit fault.

[0047] The short-circuit location identification device (28) stores test patterns representing predetermined combinations for turning on switching elements of an inverter (25), and identifies a switching element malfunctioning due to a short circuit or a phase malfunctioning due to a ground fault or a power supply fault (or power supply short circuit) based on voltage values ​​of motor terminals, the stored test patterns, and a detected current in each of the phases flowing in response to the test pattern.

[0048] Furthermore, the method disclosed in WO 2008 / 129658 A1 is used for a single winding drive system, but for a plurality of winding drive systems, the abnormality detecting means may be implemented for each of the winding drive systems, and for a winding drive system in which an abnormality is detected, the short-circuit location identifying means may be used to identify a short-circuit location.

[0049] In this way, when a failure occurs, the primary failure detecting means 61 outputs a primary failure system determination result indicating whether the failure is in the first winding drive system or in the second winding drive system, and a primary failure content identification result indicating on which switching element a short-circuit failure occurs, in which phase a power supply failure or a ground fault occurs, between which phases a short-circuit failure occurs between phases, or on which switching element or motor winding a circuit open-circuit failure occurs.

[0050] Now a description of an overview of an operation when a failure occurs is given.

[0051] Assume that a short-circuit fault or an open-circuit fault occurs in the first winding drive system. The first torque current command value Iq01* in the first winding drive system, which is on the faulty side, is input to the fault-time current control device 30 via the switching device 38. The fault-time current control device 30 then calculates a fault-time phase voltage command Vf* as a phase voltage command V1* on the faulty side and provides the fault-time phase voltage command V1* to the first winding drive system via the switching device 36.

[0052] As a result, the control appropriate to the content of the disturbance is executed and generates, in the winding drive system on the disturbed side, a torque for restraining torque pulsation and braking torque caused by the disturbance, or a torque for rapidly leaving, by acceleration, a rotation angle range in which braking torque is generated.

[0053] On the other hand, for the second winding drive system, which is the normal side, the second torque current command value Iq02* can be formed by a command forming means (not shown) into a command to cancel a braking torque component on the faulty side or into a torque current command to quickly exit, by acceleration, the rotation angle range in which braking torque is generated. Then, the thus formed command is used as the second torque current command value Iq2*, which is an input to the second normal-time current control means 32.

[0054] The normal-time phase voltage command Vn2*, which is an output of the second normal-time current control device 32, is supplied as the phase voltage command V2* to the second winding drive system on the normal side via the switching device 37. In the second winding system on the normal side, the torque current precisely tracks the torque current command value, taking into account the effect of the disturbed first winding drive system.

[0055] Now, a description will be given specifically of an operation in the first winding drive system when a short-circuit fault or a circuit breakage fault occurs, with reference to the block diagram in the above-mentioned Fig. 2. Based on the primary faulty system determination result acquired by the primary fault detection means 61, the torque current command value Iq01* on the faulty side is selected by the switching means 38 and is input as a faulty-side torque current command value Iq0f* to the fault-time current control means 30. Furthermore, the phase current detection value I1dtc on the faulty side is selected by the switching means 39 and is input as a faulty-side phase current detection value Ifdtc to the fault-time current control means 30.

[0056] Further, the primary disturbance content identification result acquired by the primary disturbance detection means 61 and the motor rotation angle signal θ are input to the disturbance-time current control means 30, and control appropriate to the disturbance content is performed. Note that the operation of the disturbance-time current control means 30 will be described later. Then, the disturbance-time phase voltage command Vf* calculated by the disturbance-time current control means 30 is selected by the switching means 36 and output as the first phase voltage command V1*.

[0057] On the other hand, the second torque current command value Iq02* on the normal side is formed into a torque current command suitable for the fault content and is input as the second torque current command value Iq2* to the second normal-time current control means 32. Then, the second phase voltage command Vf* calculated by the second normal-time current control means 32 is selected by the switching means 37 and is output as the second phase voltage command V2*.

[0058] In the following, as a first case, taking as an example a case where the switching element VN1 on the lower side in the V1 phase of the first winding drive system is disturbed by a short circuit as a primary disturbance, a description will be given of the operation of the disturbance time current control means 30. Fig. Fig. 4 is a configuration diagram of the fault-time current control device 30 according to the first embodiment of the present invention. As the fault-time current control device 30, a Fig. 3 of WO 2007 / 129359 A1, and Fig. 4 according to the present invention illustrates a block diagram similar to this conventional technology.

[0059] An operation of the block diagram of Fig. 4 is the same as that of WO 2007 / 129359 A1, a detailed description thereof is thus omitted, and a control configuration suitable for the case where the switching element VN1 is faulty due to a short circuit is provided. Phase current command shaping means 50 outputs fault-time phase current commands Ifu*, Ifv*, and Ifw* based on the faulty-side torque current command value Iq0f*, the motor rotation angle signal θ, and a motor rotation angular velocity signal that is a derivative of the motor rotation angle signal θ. Based on the commands, the fault-time phase current command Vf* is generated by a control component at a subsequent stage, which will not be described in detail.

[0060] Furthermore, in a rotation angle range where positive torque cannot be generated, all of the switching elements in the inverter on the faulty side are temporarily turned off by the selective switching element turning-off device 53, thereby limiting a braking torque generated by a current flowing through a short-circuit path generated by an induced voltage. An operation of the phase current command shaping device 50 is described in WO 2007 / 129359 A1, and a detailed description thereof is therefore omitted.

[0061] Now, a description will be given of the current and torque generated by the first winding drive system on the faulty side when the switching element VN1 in the first winding drive system is faulty due to a short circuit as a primary fault. When the switching element VN1 is short-circuited, the V phase is short-circuited to the negative electric potential of the power supply. Accordingly, the phase current that can be generated is limited, and the current in the V phase can only be generated in the negative direction. Thus, in a rotation angle range where a current larger than currents in other phases must originally flow in the V phase, a positive torque cannot be generated.

[0062] Fig. 5 in WO 2007 / 129359 A1 illustrates a waveform that can be generated and a unit phase current for realizing the torque waveform when it is required that a torque current is 1. As in Fig. As illustrated in Figure 5(B) in WO 2007 / 129359 A1, torque cannot be generated in the rotation angle from 0 degrees to 60 degrees. Conversely, when the motor is rotated by an external force, an induced voltage can generate a braking torque. In this rotation angle range, the selective switching element deactivation device 53 temporarily deactivates the switching elements, thereby reducing the current paths as much as possible and reducing the braking torque.

[0063] Now a description of a reason for generating the braking torque is given. Fig. 5 is an explanatory diagram describing the reason for generation of braking torque according to the first embodiment of the present invention, and more specifically, it is a diagram illustrating a path of a circulating current flowing due to an induced voltage when the lower switching element in the V-phase fails due to a short circuit. When the switching element VN1 fails due to a short circuit, even if a turn-off command is provided to all of the switching elements, a diode generally arranged in parallel with the switching element is brought into the ON state when the lower switching element in the V-phase fails due to a short circuit. As a result, as shown in Fig. 5, a current is generated which circulates through the location where a short-circuit fault has occurred, the diode and the winding.

[0064] As in Fig. As illustrated in Figure 5, this current does not flow through the power supply and thus cannot be prevented even by opening the power supply relay 3. The circulating current generated by the induced voltage generates the braking torque on the motor 5. Furthermore, a similar circulating current is also generated in a ground fault or a power supply fault of a motor line.

[0065] In the primary fault, the number of short-circuit fault locations is one, and the above-mentioned fault time current control can prevent a state in which an excessive current flows from the power supply, and thus the control can be continued while the power supply relay 3 is in the connected state.

[0066] In this way, even if a short-circuit fault occurs in the winding drive system as the primary fault, the fault-time current control device 30 can suppress as much as possible that the braking torque is generated by the current in the short-circuit fault path on the faulty side, and by adding the torque on the normal side, a sufficient torque close to that in the normal time can be realized.

[0067] In the following, as a second case, taking as an example a case where the switching element or the motor line in the U1 phase of the first winding drive system is disturbed by an open circuit as a primary disturbance, a description will be given of the operation of the disturbance-time current control device 30. In this case, the disturbance-time current control device 30 may Fig. 3 of WO 2005 / 091488 A1. No detailed description of the operation of a block diagram of Fig. 3 of WO 2005 / 091488 A1, but a control configuration is provided which is suitable for a case where the U phase is disturbed by a circuit break.

[0068] With this configuration, even when an open-circuit disturbance occurs as a primary disturbance in a winding drive system, control for compensating for a torque deficiency at a motor rotation angle at which the torque generated in the disturbance by the open-circuit disturbance becomes zero can be provided, and by adding the torque on the normal side, a sufficient torque close to that in the normal time can be realized.

[0069] As described above, in the fault time current control device 30, the control for the short-circuit fault and the control for the open-circuit fault are provided, and based on the primary fault content identification result, the fault time current control device 30 is configured to switch the control to be used.

[0070] Now, a specific description will be given of an operation and a related configuration for a case where, after a primary fault occurs, a secondary fault occurs on the faulty side while the fault-time current control means 30 continues the control on the faulty side.

[0071] As in Fig. As illustrated in Figure 3, based on the primary faulty system determination result by the primary fault detection means 61 in the switching means 65, the phase current detection value I1dtc or I2dtc of the system on the faulty side is selected and input to the secondary fault detection means 64. The secondary fault detection means 64 selects and executes a method for detecting a secondary fault based on the primary fault content identification result.

[0072] Taking as an example a case where the switching element VN1 on the lower side in the V1 phase of the first winding drive system is disturbed by a short circuit as a primary disturbance (corresponding to the above-mentioned first case), a description will be given below of the secondary disturbance detection and an action to be taken after the detection.

[0073] The secondary fault detecting means 64 includes a phase current excess detecting means, a phase current command excess detecting means, and a secondary circuit open circuit fault detecting means, and after a primary fault is detected, these detecting means are activated and are executed.

[0074] First, a description will be given of an operation of the phase current excess detection device. Fig. 6 is a flowchart illustrating a sequence of operation related to the phase current excess detection means in the secondary disturbance detection means 64 according to the first embodiment of the present invention.

[0075] In step S21, the phase current excess detection means determines whether the magnitude of the phase current detection value in each of the phases is greater than a predetermined maximum current value Imax. Then, if the phase current excess detection means determines that there is a state where the magnitude of the phase current detection value is greater than the predetermined maximum current value Imax, in step S22, the phase current excess detection means determines whether the state has continued for a period equal to or longer than a predetermined determination period Ti.

[0076] If the phase current excess detection means determines that the condition has continued for the above-mentioned period, the phase current excess detection means determines in step S23 that an abnormal state of excessive phase current has occurred in the phase in which the determination condition was established in the previous step S21, and determines the presence of the phase current excess. On the other hand, if the determination in the previous step S21 or S22 is negative (corresponding to "NO" in steps S21 or S22 of Fig. 6), the phase current excess detection device does not determine the presence of the phase current excess, and the processing by the phase current excess detection device is repeated again.

[0077] Here, I1dtc x in step S21 means that x takes any one of U1, V1 and W1, and represents any one of the phase current detection values ​​in the respective phases Iu1dtc, Iv1dtc and Iw1dtc. Moreover, in order to detect a disturbance in the second winding drive system, the same disturbance detection is carried out for the respective phases U2, V2 and W2.

[0078] As described above, the configuration is provided for detecting a secondary disturbance based on whether or not the magnitude of the current detection value of each of the phases is larger than the predetermined maximum current value, and thus it is possible to detect in which phase a secondary disturbance has occurred and the abnormality of the excessive phase current has been generated.

[0079] A description will now be given of the operation of the phase current command excess detection device. Fig. 7 is a flowchart illustrating a sequence of operation related to the phase current command excess detection means in the secondary disturbance detection means 64 according to the first embodiment of the present invention.

[0080] In step S31, the phase current command excess detection means determines whether or not a magnitude |I1dtc_xv| of a detection value of a current flowing between a faulty phase and a normal phase is greater than a value of a sum of a magnitude |Ifxv*|, a target value thereof, and a predetermined fault current value β. When the phase current command excess detection means determines that the magnitude is greater than the value of the sum (corresponding to "YES" in step S31 of Fig. 7), then the phase current command excess detection means proceeds to step S33, and when the phase current command excess detection means determines that the magnitude is not greater than the sum (corresponding to “NO” in step S31 of Fig. 7), the phase current command excess detecting means proceeds to step S32.

[0081] In step S32, the phase current command excess determination means determines whether the detection value I1dtc_xv of the current flowing between a faulty phase and a normal phase, in a direction opposite to the target value Ifxv* thereof, is the predetermined fault current value β. If the phase current command excess determination means determines that the current detection value I1dtc_xv is the predetermined fault current value β in the opposite direction (corresponding to "YES" in step S32 of Fig. 7), the phase current command excess determining means proceeds to step S33.

[0082] Then, in step S33, the phase current command excess detecting means determines whether or not the determination condition in the previous step S31 or S32 has been established for a period equal to or longer than a predetermined determination period Tir. If the phase current command excess detecting means determines that the determination condition has been established for the period equal to or longer than the predetermined determination period Tir (corresponding to “YES” in step S33 of Fig. 7), the phase current command excess detecting means determines in step S34 that the abnormality that the magnitude of the phase current exceeds the magnitude of the command or the abnormality that the phase current is in the direction opposite to the command has occurred, and determines the presence of the phase current command excess.

[0083] On the other hand, if the determination in the previous step S32 or step S33 is negative (corresponding to “NO” in steps S32 and S33 of Fig. 3, the phase current command excess detection means does not determine the presence of the phase current excess, and the processing by the phase current command excess detection means is repeated again.

[0084] Here, I1dtc_xv in step S31 represents the difference between the phase current detection value I1dtc_x in an x-phase and the phase current detection value I1dtc_v in the V1 phase where a primary fault occurred, namely (I1dtc_x-I1dtc_v). Furthermore, Ifxv* in steps S31 and S32 represents the difference between the phase current command Ifx* in the x-phase and the phase current command Ifv* in the V1 phase where a primary fault occurred, namely (Ifx*-Ifv*). Furthermore, symbol x represents any of U1 and W1 other than the phase where a primary fault occurred.

[0085] The fault time current control device 30 of Fig. 4 of the claimed application, described as the conventional technology, is configured to perform control by controllers 42 and 43 when a short-circuit fault occurs based on the difference in a state quantity between a phase in which a primary fault is generated and the other phases, as provided by subtrahends 72 and 73. Thus, in the phase current command excess detection means in the secondary fault detection means 64 according to the present invention, by referencing the processing by the fault-time current control means 30, the method is improved to the secondary fault detection method suitable for a faulty state based on the differences.

[0086] By configuring the fault detection method based on an existing primary fault condition or the fault time control device, a secondary fault can be accurately detected. Furthermore, by determining the sign and magnitude of the current command value and the current detection value of each phase, a secondary fault can be accurately detected. Furthermore, by determining the sign and magnitude based on the differences in the current command value and the current detection value between the phases, the secondary fault can be more accurately detected.

[0087] Now, a description will be given of the operation of the secondary circuit open circuit fault detecting device. Fig. 8 is a flowchart illustrating a flow of an operation related to the secondary circuit open-circuit failure detection means in the secondary failure detection means 64 according to the first embodiment of the present invention. The secondary circuit open-circuit failure detection means is basically the same as a method disclosed in JP 2007-244028 A, but, as in the phase current excess detection means, the secondary circuit open-circuit failure detection means is different from that method in that the currents and voltage commands to be used for determination are replaced by the difference in state quantity between a phase in which the primary failure has occurred and the other phases.

[0088] In step S41, the secondary circuit open-circuit failure detecting means determines whether or not a magnitude |I1dtc_xv| of the detection value of the current flowing between a faulty phase and a normal phase is equal to or greater than a predetermined current value Ith, and when the secondary circuit open-circuit failure detecting means determines that the magnitude is equal to or less than the predetermined current value Ith, the secondary circuit open-circuit failure detecting means proceeds to step S42.

[0089] Then, in step S42, the secondary circuit open-circuit abnormality detecting means determines whether or not an engine speed N is equal to or less than a predetermined speed N0, and when the secondary circuit open-circuit abnormality detecting means determines that the engine speed N is equal to or less than the predetermined speed N0, the secondary circuit open-circuit abnormality detecting means proceeds to step S43.

[0090] Then, in step S43, the secondary circuit open-circuit failure detecting means determines whether or not a voltage Vps of the power supply is equal to or less than a predetermined power supply voltage value Vth, and when the secondary circuit open-circuit failure detecting means determines that the voltage Vps is equal to or less than the predetermined power supply voltage value Vth, the secondary circuit open-circuit failure detecting means proceeds to step S44.

[0091] In step S44, the secondary circuit open-circuit abnormality detecting means determines whether or not a magnitude |Vf*_xv| of the voltage command of the voltage applied between a faulty phase and a normal phase is equal to or greater than a predetermined voltage command value Vfth, and when the secondary circuit open-circuit abnormality detecting means determines that the magnitude is not equal to or less than the predetermined voltage command value Vfth, the secondary circuit open-circuit abnormality detecting means proceeds to step S45.

[0092] Then, in step S45, the secondary circuit open-circuit failure detecting means determines whether or not the state in which the determination condition is not established (NO) in the previous step S44 has continued for a period equal to or longer than a predetermined period To, and, when the secondary circuit open-circuit failure detecting means determines that the negative determination state has continued for the period equal to or longer than the determination period To, the secondary circuit open-circuit failure detecting means proceeds to step S46, determines that the phase is in the state of the circuit open-circuit failure, and determines the presence of the secondary circuit open-circuit failure.

[0093] On the other hand, when the determination is negative in step S41, S42, S43, or S45 (namely, NO in each of the steps), and when the determination in step S44 is affirmative (namely, YES in step S44), the presence of the secondary circuit open-circuit failure is not determined, and the processing by the secondary circuit open-circuit failure detecting means is repeated again.

[0094] Here, Vf*_xv in step S44 represents the difference between the phase voltage command value Vf*_x in the x-phase and the voltage value Vf_v in the faulty phase V1, namely (Vf*_x-Vf_v). Currently, the lower switching element VN1 in the V1 phase is being faulted by a short circuit, and thus, the voltage value in the faulty phase V1 is stuck at the negative electric potential of the power supply. If the voltage value Vf_v is represented by the voltage with respect to the neutral point on the voltage command scale, the voltage value Vf_v is a negative value VN, which is half of the power supply voltage Vps, namely -Vps / 2.

[0095] With this configuration, when the primary fault is a short-circuit fault, the secondary circuit open-circuit fault detecting means determines whether or not, based on the difference in state quantity between the faulty phase and the normal phase, the current response matches the voltage command, and when the responding current is small even though the voltage command is applied to the faulty phase and the normal phase, the secondary circuit open-circuit fault detecting means determines that an abnormality is caused by non-conduction of the current and can identify the presence of the secondary circuit open-circuit fault.

[0096] In this way, by configuring the failure detection method based on an existing primary failure state or based on a control method for the existing primary failure state, the secondary failure detection means 64 can accurately detect a secondary failure.

[0097] Furthermore, by determining the sign and magnitude of the voltage command value and the current detection value for each of the phases, a secondary disturbance can be detected precisely, and by determining, based on the differences in the voltage command value and the current detection value between the phases, the sign and magnitude, the secondary disturbance can be detected more precisely.

[0098] In this way, the secondary fault detection device 64 is configured to determine a faulty state based on the current in each of the phases and the command value thereof or the command value for the voltage of each of the phases, and can thus accurately detect the secondary fault. Furthermore, the secondary fault detection device 64 is configured to determine a faulty state based on the difference in current between the phases and the difference in the command value between the phases or the difference in the command value for the voltage between the phases, and can thus detect a fault based on an existing primary fault state or a control method for the fault state, and can detect the fault more accurately.

[0099] Now, a description will be given of a state of the current in a case where a short-circuit fault has occurred in a winding drive system as the primary fault, and then a short-circuit fault occurs in a winding drive system in the same system by comparing two cases of Fig. 9 and Fig. 10 can be used as examples.

[0100] Fig. 9 is an explanatory diagram illustrating a state of a current in a case where a primary failure is a short-circuit failure of the switching element on the lower side in the V phase, and a secondary failure is a short-circuit failure of the switching element on the opposite side (upper side) in the same phase, according to the first embodiment of the present invention. Note that the sequence of the primary failure and the secondary failure may be reversed. In this case, across the two locations of the short-circuit failure, the positive electrode and the negative electrode of the power supply are substantially in the short-circuit state, and an excessive current flows from the power supply. As a result, excessive heat generation and excessive power consumption occur.

[0101] Note that instead of the short circuit of the switching element, even if faults (ground fault and power supply fault) occur, that the inverter output and the connecting wire of the motor line are short-circuited in the same phase with the positive electric potential and the negative electric potential of the power supply, as long as two places are respectively short-circuited with the positive electrode side and the negative electrode side in the same phase, a similar excess current occurs.

[0102] Fig. 10 is an explanatory diagram illustrating a state of a current in a case where a primary fault is a short-circuit fault of the switching element on the lower side in the V phase, and a secondary fault is a short-circuit fault of the switching element on the opposite side (upper side) in another phase (U phase in this case), according to the first embodiment of the present invention. The sequence of the primary fault and the secondary fault may be reversed. In this case, a closed circuit with the negative electric potential and the positive electric potential of the power supply is formed across the two locations of the short-circuit fault and the motor windings, and an excess current flows out from the power supply unit. As a result, excessive heat generation and excessive power consumption occur.

[0103] Compared with the case of Fig. 9 falls in the case of Fig. 10 a voltage by an amount corresponding to the path through the windings, and the current thus decreases, but the power supply is still in a short circuit, and the current is excessive. Note that instead of the switching element short circuiting, even when faults (ground fault and power supply fault) occur, the inverter output and the connecting wire of the motor line are short-circuited to the positive electrical potential and the positive electrical potential of the power supply, a similar excess current flows.

[0104] The Fig. 9 and Fig. The excess current conditions illustrated in Figure 10 are detected by the phase current excess detection means and the phase current command excess detection means of the secondary fault detection means 64. When any of the phase current excess detection means and the phase current command excess detection means determines a fault, the secondary fault detection means 64 determines that excess current may be flowing from the power supply and issues a power supply relay open command, thereby opening the power supply relay 3. As a result, the electrical connection between the power supply and the inverter can be immediately severed, thereby preventing excess current from flowing from the power supply.

[0105] On the other hand, since as a secondary fault, when the secondary circuit open circuit fault detecting means detects a circuit open circuit fault, an excess current as described above cannot possibly occur, it is not necessary to open the power supply relay, and the control on the normal side can be continued.

[0106] In the following, a description will be given of the secondary disturbance detection and response after the detection by taking as an example a case where the switching element in the U1 phase of the first winding drive system or the motor line is disturbed by a circuit break (corresponding to the above-mentioned second case).

[0107] The secondary fault detecting means 64 includes the phase current excess detecting means, the phase current command excess detecting means, and the secondary circuit open circuit fault detecting means, and after a primary fault is detected, these detecting means are activated and are executed.

[0108] The phase current excess detection device may be configured to perform the same operation as in Fig. 6 is used to describe the first case. Furthermore, when a primary fault is a circuit-opening fault, the phase current command excess detection device may be configured to make a determination for each phase based on a comparison with the command without acquiring the difference between the faulty phase and each of the normal phases. Therefore, a detailed description thereof will be omitted.

[0109] The secondary circuit open circuit fault detection means may be the method of JP 2007-244028 A, as is the method implemented in the primary fault detection. This is because, unlike in a short circuit fault, the voltage applied to the winding in each of the normal phases can be controlled for each of the phases by the inverter, and the same method as in the normal time can be adopted.

[0110] With this configuration, when a phase of the first winding drive system is disturbed by a circuit break as a primary fault, and then a secondary fault occurs in the same winding drive system, the secondary fault detection device 64 can detect the secondary fault. Once the secondary fault is detected, control on the disturbed side is further restricted or stopped, and control for the winding drive system on the normal side is continued.

[0111] Because the number of short circuit faults on the faulty side is as much as one place, a closed circuit containing the power supply is not formed by the fault location, an excess current may not flow, it is not necessary to open the power supply relay 3, and the control can continue.

[0112] Now, a description will be given of an overall operation by the current control means 23 with respect to the primary disturbance detection and the secondary disturbance detection realized by the above-mentioned embodiment with reference to a flowchart. Fig. 11 is a flowchart illustrating a sequence of processing by the current control device 23 according to the first embodiment of the present invention.

[0113] First, in step S01, the current controller 23 starts normal control, and in step S02, branches the control processing depending on the detected content of a primary abnormality. If a abnormality is not detected in step S02, then in step S03, the current controller 23 continues normal control, and in step S04, when an ignition switch serving as a start command for the engine control device is turned on, the current controller returns to step S02.

[0114] Furthermore, in the primary fault detection in the previous step S02, when a short-circuit fault (the fault includes a ground fault and a power supply fault fault, but a description of the short-circuit fault will be given below) is detected, the current control device 23 starts the fault-time current control (namely, the short-circuit fault time control) appropriate for the short-circuit fault through the fault-time current control device 30 in step S05. Then, in step S06, the current control device 23 performs the secondary fault detection during the short-circuit fault, which is the primary fault. If the current control device 23 detects a short-circuit fault as a secondary fault, in step S07, the current control device 23 sets the power supply relay to the open state through the power supply relay open command, and stops the control in step S18.

[0115] Moreover, in the secondary failure detection in step S06, when a secondary failure is not detected during the short-circuit failure which is the primary failure, in step S08 the current control means 23 maintains the short-circuit failure timing, and in step S09, when the ignition switch is turned on, the current control means 23 returns to step S06.

[0116] In the secondary fault detection in step S06, if an open-circuit fault is detected during the short-circuit fault, which is the primary fault, the current control device 23 further resumes control for the normal-side system in step S10. The system on the faulty side may be configured to stop control or continue further restricted control. Then, in step S11, if the ignition switch is / will be turned on, the current control device 23 returns to step S10.

[0117] Furthermore, in the primary failure detection in the previous step S02, when the current control means 23 detects an open-circuit failure, in step S12, the current control means 23 starts a failure-time current control (open-circuit failure timing) appropriate for the open-circuit failure through the failure-time current control means 30. Then, in step S13, the current control means 23 performs secondary failure detection during the open-circuit failure, which is the primary failure. If a secondary failure is not detected, the current control means 23 maintains the open-circuit failure timing in step S14. In step S15, when the ignition switch is turned on, the current control means 23 returns to step S13.

[0118] On the other hand, in the secondary failure detection in step S13, if a secondary failure is detected, the power control device 23 continues control for the system on the normal side in step S16. The system on the failure side may be configured to stop control or continue further restricted control. In step S17, if the ignition switch is / will be turned on, the power control device 23 returns to step S16.

[0119] When the ignition switch is / becomes turned off in any of steps S09, S11, S15 and S17, the current control means 23 stops the control in step S18.

[0120] Now, a description will be given of effects brought about by the engine control apparatus according to the above-described first embodiment.

[0121] A control device for controlling a motor provided with a plurality of winding sets may be configured such that, when a short-circuit fault, a ground fault, or a power supply fault fault is detected as a primary fault in an inverter or a part of windings, control for an inverter on the normal side is continued, and, if the secondary fault detecting means detects a secondary fault in a winding or the inverter on the side of the primary fault, further the power supply relay is opened.

[0122] As a result, an excess current that may occur when a secondary fault occurs is prevented by opening the power supply relay, thereby preventing excessive heat generation and excessive power consumption. Furthermore, to prevent an excess current caused by a secondary fault during a primary fault, a provision for disconnecting an electrical connection with the power supply only on the faulty side, which is required in the conventional case, is no longer necessary. As a result, the power supply relays can be common to the respective winding drive systems, and thus, it is possible to obtain a remarkable effect of reducing costs, which is not provided by the conventional case.

[0123] Furthermore, a configuration may be provided in which a fault-time current control means for generating a fault-time voltage command based on a content of a fault detected by the primary fault detecting means is provided, and when the primary fault detecting means detects a short-circuit fault of a switching element or a fault due to ground fault or power supply fault of the inverter or the winding, the control of the inverter on the fault side is continued by the fault-time voltage command.

[0124] As a result, when a primary fault occurs, the power supply relay is not opened, and control for the winding drive system on the faulty side continues, generating a torque as close as possible to that in the normal time even on the faulty side. Consequently, the braking torque generated by the fault can be reduced as much as possible, and an effect of providing sufficient output torque close to that in the normal time is achieved.

[0125] Furthermore, the secondary fault detecting means determines whether a secondary fault is a short-circuit fault in a winding or an inverter or an open-circuit fault, and there may be provided a configuration in which, when a result of the determination by the secondary fault detecting means is an open-circuit fault, even after the occurrence of the secondary fault, the control for the inverter on the normal side can be continued.

[0126] As a result, it is possible to obtain an effect that, because it can be determined whether or not the secondary fault causes an excess current to flow, and when it is determined that a circuit breakage fault exists, an excess current does not flow even after the occurrence of the secondary fault, the control for the winding drive system can be continued on the normal side, thereby causing the torque output to be as close as possible to that in the normal time, and preventing excessive heat generation and excessive power consumption.

[0127] Furthermore, a configuration may be provided in which, when the primary fault detecting means detects a circuit-opening fault of the winding or the inverter, and further the secondary fault detecting means detects a fault of the winding or the inverter on the faulty side, even after the secondary fault occurs, the control for the inverter on the normal side can be continued.

[0128] If the primary fault is a short-circuit fault and a secondary fault is subsequently detected, the number of short-circuit fault locations is one, and it can be determined that excess current is not flowing. Therefore, it is possible to obtain the effect that after the secondary fault occurs, control for the winding drive system can be resumed on the normal side, thereby causing the torque output to be as close as possible to that in the normal time, and also preventing excessive heat generation and power consumption.

[0129] Furthermore, the above-mentioned motor control device and the motor of the plurality of winding sets can be applied to an electric motor control device and a motor of an electric power steering device as described in WO 2007 / 129359 A1. As a result, an excess current that may occur when a secondary fault occurs is prevented by opening the power supply relay, thereby preventing excessive heat generation and excessive power consumption.

[0130] Furthermore, as in the conventional case, to prevent excess current from a secondary fault during a primary fault, a provision for disconnecting an electrical connection to a power supply only on the faulted side is no longer necessary. As a result, the power supply relays can be common to the respective winding drive systems, thus achieving a remarkable cost-reduction effect, which is not provided by the conventional case.

[0131] Furthermore, when a disturbance occurs, by limiting the braking torque to a minimum value, torque pulsation can be limited, and control can continue on the normal side. As a result, sufficient output torque can be obtained, a torque close to that in normal time can be realized, and thus it is possible to achieve an effect that can sufficiently reduce the discomfort felt by a driver during the disturbance.

[0132] Furthermore, in the configuration of this embodiment, fault time current control can be achieved without providing a relay between the inverter and the windings while limiting the braking torque. As a result, the cost of the motor relays can be reduced, and a low-cost effect can also be achieved.

[0133] Note that in the above-mentioned embodiment, the windings are configured as a star connection, but these windings can be configured as a delta connection, and as a control method, the same control effect can be achieved by processing an offset of a motor rotation angle used for command generation, thereby shifting the phase of the command value. Furthermore, with regard to disturbance detection, a difference is only the phase shift and the like, and thus, the method can be adopted without specifically changing the method, thereby acquiring the same effect.

[0134] Moreover, in the above-mentioned embodiment, the secondary abnormality detection means detects a secondary abnormality in a winding drive system on the side where a primary abnormality has occurred. However, the present invention is not limited to this case. For example, abnormality detection in a winding drive system on a normal side where a primary abnormality has not occurred may be performed by the first system abnormality detection means 62 or the second system abnormality detection means 63, which is the normal side, in the primary abnormality detection means 61, and depending on a abnormality content detected by the first system abnormality detection means 62 or the second system abnormality detection means 63, the abnormality time current control may be executed, or the power supply relay may be opened.

Claims

[1] A motor control device (10) for supplying a motor (5) with electrical energy from a power supply (4) and for controlling currents to flow through a plurality of winding sets of the motor (5), comprising: a plurality of inverters (21, 22) having a switching element in each of phases of the plurality of winding sets for controlling a voltage applied to each of the phases, thereby controlling a current to be supplied from the power supply (4) to each of the phases of the plurality of winding sets; a power supply relay (3) provided between the power supply (4) and the plurality of converters (21, 22) for disconnecting an electrical connection; and a current control device (23) for providing, in dependence on a target value of a torque to be generated by the motor (5), to each of the plurality of inverters (21, 22), a voltage command corresponding to the voltage, thereby controlling the current to flow through the plurality of winding sets, wherein: the current control device (23) comprises: a primary fault detecting means (61) for detecting the primary fault of any one of the plurality of winding sets and the plurality of inverters (21, 22); and secondary disturbance detecting means (64) for detecting, after a primary disturbance is detected, a secondary disturbance occurring in any one of a winding and an inverter (21, 22) in a system in which the primary disturbance has occurred; and the current control device (23) is configured: for continuing control for an inverter (21, 22) on a normal side when the primary fault detecting means (61) detects any one of a short-circuit fault, a ground fault, and a power supply fault as the primary fault in any one of the plurality of inverters (21, 22) and a part of the plurality of winding sets; and further for opening the power supply relay (3) when the secondary fault detecting means (64) detects the secondary fault, the secondary fault being a short-circuit fault in a pair of a winding and an inverter on a faulty side. [2] The motor control device (10) according to claim 1, wherein the power supply relay (3) comprises a single power supply relay (3) provided between the power supply (4) and the plurality of inverters (21, 22). [3] Engine control device (10) according to claim 1 or 2, wherein: the current control means (23) further comprises fault-time current control means for generating, when the primary fault detection means (61) detects the primary fault, a fault-time voltage command directed to the system in which the primary fault occurred, based on the target value and a detection value of a current flowing through the winding in the system in which the primary fault occurred; and the current control means (23), when the primary fault detection means (61) detects a fault, continues control for an inverter (21, 22) in a system in which the fault has occurred, by the fault-time voltage command generated by the fault-time current control means (30). [4] Engine control device (10) according to one of claims 1 to 3, wherein: the secondary fault detecting means (64) determines whether a cause of the detected secondary fault is any one of a short-circuit fault and an open-circuit fault; and the current control means (23), when the secondary fault detecting means (64) determines that the cause of the secondary fault is a circuit breakage fault, after the occurrence of the secondary fault, continues the control for the inverter (21, 22) on the normal side in which neither of the primary fault and the secondary fault occurs. [5] The motor control device (10) according to any one of claims 1 to 4, wherein, when the primary failure detection means (61) detects a circuit breakage failure in any one of the plurality of winding sets and the plurality of inverters (21, 22) and further the secondary failure detection means (64) detects the secondary failure in any one of the winding and the inverter (21, 22) in the system in which the primary failure has occurred, after the occurrence of the secondary failure, the current control means (23) continues the control for the inverter (21, 22) on the normal side in which none of the primary failure and the secondary failure occurs. [6] The motor control device (10) according to any one of claims 1 to 5, wherein the secondary disturbance detecting means (64) detects the secondary disturbance based on a current detection value and any one of the target value and the voltage command in each of the phases of the plurality of winding sets. [7] The motor control device (10) according to any one of claims 1 to 5, wherein the secondary disturbance detecting means (64) detects the secondary disturbance based on a difference in a current detection value and a difference in any one of the target value and the voltage command in each of the phases of the plurality of winding sets. [8] Engine control device (10) according to one of claims 1 to 7, wherein: the current control device (23) is configured to: Carrying out, when the primary fault detected by the primary fault detecting means (61) is a short-circuit fault, a short-circuit fault current control suitable for the short-circuit fault; and When the primary fault detected by the primary fault detecting means (61) is an open-circuit fault, executing an open-circuit fault current control suitable for the open-circuit fault; and the secondary fault detection means (64) detects the secondary fault in dependence on a state of the current control based on an existing primary fault. [9] A current control method applied to a motor control device (10) for supplying a motor (5) with electrical power from a power supply (4) and for controlling currents to flow through a plurality of winding sets of the motor (5), wherein the engine control device (10) comprises: a plurality of inverters (21, 22) having a switching element in each of phases of the plurality of winding sets for controlling a voltage to be applied to each of the phases, thereby controlling a current to be supplied from the power supply (4) to each of the phases of the plurality of winding sets; a power supply relay (3) provided between the power supply (4) and the plurality of converters (21, 22) for disconnecting an electrical connection; and a current control device (23) for providing, in dependence on a target value of a torque to be generated by the motor (5), to each of the plurality of inverters (21, 22), a voltage command corresponding to the voltage, thereby controlling the current to flow through the plurality of winding sets, wherein the current control method comprises: detecting, by the current control means (23), a primary fault of any one of the plurality of winding sets and the plurality of inverters (21, 22); and detecting, by the current control means (23), after a primary fault is detected, a secondary fault occurring in any one of a winding and an inverter (21, 22) in a system in which the primary fault has occurred; and Continuing, by the current control means (23), when any of a short-circuit fault, a ground fault, and a power supply fault fault is detected in any one of the plurality of inverters (21, 22) and a part of the plurality of winding sets, upon detecting a primary fault, as the primary fault, a controller for an inverter (21, 22) on a normal side; and Opening the power supply relay (3) by the current control device (23) when the secondary fault is detected, wherein the secondary fault is a short-circuit fault in a pair of a winding and an inverter on a faulty side. [10] An electric power steering apparatus using the motor control device (10) according to any one of claims 1 to 8.

Images