JP6965725B2 - Anomaly detection device - Google Patents

Description

The present invention relates to an abnormality detecting device for detecting an abnormality in a power converter that supplies electric power to a multi-phase rotating machine.

Conventionally, in the initial check before the start of driving a multi-phase rotary machine, an abnormality detection device that detects an abnormality in a power relay that cuts off the current path from a DC power supply to a power converter and a switch element that constitutes the power converter has been used. Are known.

For example, the power converter disclosed in Patent Document 1 detects a neutral point voltage of a multi-phase winding set, and when the neutral point voltage is not within a predetermined range, any switch element of the power converter Is determined to be abnormal. By detecting the neutral point voltage, the number of terminal voltage detections is reduced for the configuration in which the voltage of each phase is detected.

Japanese Patent No. 5158528

In the main embodiment disclosed in Patent Document 1, the neutral point voltage of the three-phase winding set is detected. In this case, when the switch element of one of the three phases is abnormal, the normal determination range is set so that the abnormality can be detected. However, since the neutral point voltage is the average of the voltage of the normal phase and the voltage of the abnormal phase, as the number of phases to be checked increases, one phase becomes the voltage at the time of abnormality and the voltage at the time of normal. The difference becomes smaller. Therefore, the normal determination range that can be set becomes narrow, and the abnormality detection accuracy may decrease due to the relationship with the variation in the physical properties of each component. This problem can also occur in a configuration in which a plurality of three-phase power converters that supply power to a plurality of three-phase windings are connected in parallel to form a unit.

The present invention was created in view of the above points, and an object of the present invention is that an abnormality of a power converter can be detected with a small number of terminal voltage detections, and the same abnormality is obtained even if the number of phases increases. An object of the present invention is to provide an abnormality detection device capable of ensuring detection accuracy.

The abnormality detection device of the present invention includes a power converter (60), a pull-up resistor (Rp), a monitor diode (Du, Dv, Dw), a negative side detection resistor (Rd), and a high-select terminal voltage. A detection unit (44) and an abnormality detection unit (40) are provided. The power converter is configured by bridging a plurality of switch elements arranged on the positive side and the negative side of the DC power supply (15), and converts the power of the DC power supply into each phase winding of the multi-phase rotating machine. Supply. The pull-up resistor connects one or more phase windings of the multi-phase rotating machine to the positive side of the DC power supply.

A plurality of monitoring diodes (Du, Dv, Dw) are connection points between a switch element arranged on the positive side of the DC power supply of each phase and a switch element arranged on the negative side of the DC power supply in the power converter. The anode is connected to the connection points between the arms (Nu, Nv, Nw). The negative side detection resistor connects the gathering point (A), which is the connection point between the cathodes of the monitoring diodes of each phase, and the negative side of the DC power supply.

The high-select terminal voltage detection unit detects the high-select terminal voltage (Va), which is the voltage at the gathering point. The abnormality detector is a threshold voltage set based on the input voltage (Vpig) from the DC power supply, the voltage drop (Vf) due to the monitoring diode, the resistance value of the pull-up resistor, and the resistance value of the negative side detection resistor. And the high select terminal voltage are compared, and at least the abnormality of the power converter is detected.

In the present invention, by detecting an abnormality based on the high-select terminal voltage, the number of terminal voltages detected for detecting an abnormality of a plurality of phases can be unified. Therefore, the number of parts for detecting an abnormality can be reduced and the circuit can be miniaturized. Further, since the high select terminal voltage reflects the highest voltage among the voltages at the connection points between the arms of each phase, when any one phase is abnormal, the same voltage is detected regardless of the number of phases. Therefore, even if the number of phases increases, the voltage difference between the abnormal state and the normal state does not change, so that the same abnormality detection accuracy can be ensured.

Further, a group of units including the following components (a) to (c) are defined as "parallel power conversion units (100, 200)".
(A) A plurality of power converters (601, 602) that supply power to at least a plurality of multi-phase windings among a plurality of multi-phase windings of a multi-phase rotating machine.
(B) Multiple pull-up resistors provided in each power converter (c) Monitor diodes provided in each phase of each power converter and having their respective cathodes connected to one gathering point.

In one aspect of the present invention, one high-select terminal voltage detection unit and one abnormality detection unit are provided with one or more parallel power conversion units and have a corresponding detection resistor for one parallel power conversion unit. Is provided. In each parallel power conversion unit, the abnormality detection unit detects an abnormality in each power converter included in the parallel power conversion unit based on the voltage at the gathering point.

Even in this aspect, in the prior art of Patent Document 1, when the total number of phases included in one parallel power conversion unit increases, the difference between the abnormal voltage and the normal voltage becomes small, and the abnormality detection accuracy is improved. It may decrease. On the other hand, in the present invention of abnormality detection using the high select terminal voltage, it is possible to secure the same abnormality detection accuracy regardless of the number of power converters connected in parallel in one unit. Therefore, it is particularly effective in the electric power steering device in which the mounting space of the abnormality detection device is restricted and high-precision initial check is required.

The overall block diagram of the electric power steering apparatus to which the abnormality detection apparatus of each embodiment is applied. The block diagram of the abnormality detection apparatus of 1st Embodiment. The figure which shows the step of the initial check by 1st Embodiment. The figure which shows the high select terminal voltage at the time of a normal state and an abnormality in the initial check of FIG. The figure explaining the approximation of the voltage at the time of normal and the time of abnormality in FIG. The block diagram of the abnormality detection apparatus of 2nd Embodiment. The figure which shows the step of the initial check by 2nd Embodiment. The figure which shows the high select terminal voltage at the time of a normal state and an abnormality in the initial check of FIG. The block diagram of the abnormality detection apparatus of 3rd Embodiment. The block diagram of the abnormality detection apparatus of 4th Embodiment.

Hereinafter, a plurality of embodiments of the abnormality detection device will be described with reference to the drawings. In a plurality of embodiments, substantially the same configuration is designated by the same reference numerals and the description thereof will be omitted. The abnormality detection device of the present embodiment is used for the initial check of the device that controls the drive of the steering assist motor in the electric power steering device of the vehicle, and detects the abnormality of the switch element of the inverter, the power supply relay, the motor relay, and the like. In an electric power steering device that requires high reliability, an initial check that guarantees normal operation is particularly important.

[Configuration of electric power steering device]
FIG. 1 shows the overall configuration of the steering system 99 including the electric power steering device 90. Although the electric power steering device 90 shown in FIG. 1 is a column assist type, it can be similarly applied to a rack assist type electric power steering device. The steering system 99 includes a steering wheel 91, a steering shaft 92, a steering torque sensor 94, a pinion gear 96, a rack shaft 97, wheels 98, an electric power steering device 90, and the like.

A steering shaft 92 is connected to the steering wheel 91. The pinion gear 96 provided at the tip of the steering shaft 92 meshes with the rack shaft 97. A pair of wheels 98 are provided at both ends of the rack shaft 97 via a tie rod or the like. When the driver rotates the steering wheel 91, the steering shaft 92 connected to the steering wheel 91 rotates. The rotational motion of the steering shaft 92 is converted into a linear motion of the rack shaft 97 by the pinion gear 96, and the pair of wheels 98 are steered at an angle corresponding to the displacement amount of the rack shaft 97. The steering torque sensor 94 is provided in the middle of the steering shaft 92 and detects the steering torque Ts of the driver.

The electric power steering device 90 includes an ECU 10, a motor 80, a reduction gear 89, and the like. The motor 80 as a "multi-phase rotating machine" is, for example, a three-phase AC brushless motor. In other embodiments, a multi-phase rotating machine having four or more phases may be used. The ECU 10 of the present embodiment has a function as a motor control device and a function as an abnormality detection device.

The ECU 10 functioning as a motor control device controls the drive of the motor 80 so that the motor 80 generates a desired assist torque based on the steering torque Ts. Specifically, the ECU 10 acquires the detected values of the motor current and the electric angle, and drives the inverter as a "power converter" by current feedback control. The inverter converts the DC power of the battery as a "DC power supply" into three-phase AC power and supplies it to the motor 80. Since general motor control is a well-known technique, detailed description thereof will be omitted. The assist torque output by the motor 80 is transmitted to the steering shaft 92 via the reduction gear 89.

On the other hand, the ECU 10 functioning as an abnormality detection device detects an abnormality in the switch element of the inverter or the like as an initial check after the vehicle switch is turned on and before the motor drive is started. For example, Patent Document 1 (Patent No. 5158528) discloses a device that detects anomalies by detecting a voltage smaller than the number of legs of an inverter based on the neutral point voltage of a three-phase winding set. .. However, since the neutral point voltage is the average of the voltage of the normal phase and the voltage of the abnormal phase, as the number of phases to be checked increases, one phase becomes the voltage at the time of abnormality and the voltage at the time of normal. The difference becomes smaller. Therefore, it is an object of the present embodiment to be able to detect an abnormality of the inverter with a small number of terminal voltage detections and to secure the same abnormality detection accuracy even if the number of phases increases. ..

Next, the specific configuration of the ECU 10 and the details of abnormality detection in the initial check will be described for each embodiment. The code of the ECU of each embodiment is assigned the number of the embodiment in the third digit following "10". The code of the motor of each embodiment is distinguished by adding the number of three-phase windings of the motor to the third digit following "80".

(First Embodiment)
The first embodiment will be described with reference to FIGS. 2 to 5. As shown in FIG. 2, the ECU 101 of the first embodiment is applied to a motor 801 having a set of three-phase windings 81, 82, 83. The symbol of the AC power supply shown together with the three-phase windings 81, 82, and 83 indicates that the back electromotive voltage is generated. In the electric power steering device, even when the motor 801 is not driven, a counter electromotive voltage may be generated in the motor 801 due to the driver's steering wheel operation or an external force applied to the steering wheel.

The ECU 101 includes a power supply relay 31, a reverse connection relay 32, a smoothing capacitor 35, an inverter 60, each phase motor relay 71, 72, 73 and the like as functions of the motor control device. Further, the ECU 101 includes, as a function of the abnormality detection device, diodes Du, Dv, Dw for each phase monitor, a pull-up resistor Rp, a positive side detection resistor Ru, a negative side detection resistor Rd, and the like in the circuit. Further, the ECU 101 includes a post-relay voltage detection unit 43, a high select terminal voltage detection unit 44, and an abnormality detection unit 40.

The inverter 60 is connected to the positive side of the battery 15 via the power supply line, and is connected to the negative side of the battery 15 via the ground line. The inverter 60 is configured by bridging the switch elements 61, 62, 63 of the upper arms of the U phase, V phase, and W phase, and the switch elements 64, 65, 66 of the lower arm, and converts the power of the battery 15. Then, it is supplied to each phase winding of the multi-phase rotary machine. The switch elements 61, 62, 63 of the upper arm are "a plurality of switch elements arranged on the positive side of the DC power supply", and the switch elements 64, 65, 66 of the lower arm are "arranged on the negative side of the DC power supply". "Multiple switch elements".

In this embodiment, a MOSFET is used as the switch element 61-66 of the inverter 60. Hereinafter, the switch element of the upper arm will be referred to as "upper MOS61-63", and the switch element of the lower arm will be referred to as "lower MOS64-66". The connection points between the upper MOS61-63 and the lower MOS64-66 of each phase are defined as "arm-to-arm connection points Nu, Nv, Nw". The arm-to-arm connection points Nu, Nv, and Nw are connected to the phase windings 81, 82, and 83, respectively. Further, in the MOS 61-66, a freewheeling diode that allows a current from the low potential side to the high potential side is configured as a parasitic diode inside the element.

The power relay 31 and the reverse relay 32 are connected in series in the middle of the power line between the battery 15 and the inverter 60. The power relay 31 provided on the battery 15 side has a freewheeling diode that allows a current from the inverter 60 side to the battery 15 side. The reverse relay 32 provided on the inverter 60 side has a freewheeling diode that allows a current from the battery 15 side to the inverter 60 side. In this embodiment, the power supply relay 31 and the reverse connection relay 32 are also composed of MOSFETs.

The power relay 31 cuts off the current flowing from the battery 15 to the inverter 60 via the power line when the battery 15 is installed in the proper orientation. The reverse relay 32 cuts off the current flowing from the battery 15 to the inverter 60 via the ground wire in the reverse direction when the battery 15 is mounted in the opposite direction to the normal one. The reverse connection relay 32 is formally referred to as a "reverse connection protection relay", a "reverse connection prevention relay", or the like, but in the present specification, the term "reverse connection relay", which is a common name in the technical field, is used. To use. The smoothing capacitor 35 smoothes the input voltage to the inverter 60.

The motor relays 71, 72, and 73 of each phase have connection points Nu, Nv, and Nw between the arms of each phase.
And each phase winding 81, 82, 83. For example, when an excessive back electromotive force is generated in the motor 801 by shutting off the motor relays 71, 72, 73, it is possible to prevent the overvoltage from being applied to the upper and lower MOS 61-66 of the inverter 60. In other embodiments, the motor relay may not be provided. Hereinafter, "motor relays 71, 72, 73" and "three-phase windings 81, 82, 83" will be abbreviated as "motor relays 71-73" and "three-phase windings 81-83". ..

The pull-up resistor Rp connects one or more phase windings of the motor 801 to the positive side of the battery 15 via a power supply line. In the configuration example of FIG. 2, a pull-up resistor Rp is connected to the U-phase winding 81. In another embodiment, a pull-up resistor Rp may be connected to the V-phase winding 82 or the W-phase winding 83, or any two-phase or three-phase winding. For example, the resistance value of the pull-up resistor Rp is set to 1.3 kΩ.

In the monitoring diodes Du, Dv, and Dw, the anodes are connected to the arm-to-arm connection points Nu, Nv, and Nw of each phase, and the cathodes are connected to one point. This connection point is defined as a set point A. Since the highest voltage among the voltages of the connection points Nu, Nv, and Nw between the arms of each phase is applied to the gathering point A, the voltage at the gathering point A is called "high select terminal voltage Va".

The positive side detection resistor Ru connects the gathering point A and the power supply line, that is, the positive side of the battery 15, and the negative side detection resistor Rd connects the gathering point A and the ground line, that is, the negative side of the battery 15. do. For example, the resistance values of the positive side detection resistor Ru and the negative side detection resistor Rd are both set to 10 kΩ. Hereinafter, the symbols Rp, Ru, and Rd of the pull-up resistor Rp, the positive side detection resistor Ru, and the negative side detection resistor Rd are used as symbols of the resistance element, and at the same time, represent the resistance value of the resistance element.

The post-relay voltage detection unit 43 detects the post-relay voltage Vpig between the power supply line and the ground line between the reverse relay 32 and the inverter 60. The post-relay voltage Vpig corresponds to the input voltage from the battery 15 to the inverter 60. In the configuration example of FIG. 2, the post-relay voltage Vpig is detected based on the voltage division of the connection points P of the resistors 33 and 34 connected between the power supply line and the ground line. For example, the resistance values of the resistors 33 and 34 are set to 100 kΩ and 33 kΩ.

The high select terminal voltage detection unit 44 detects the high select terminal voltage Va, which is the voltage at the gathering point A. The abnormality detection unit 40 compares the threshold voltage with the high select terminal voltage Va in the initial check, and detects an abnormality in the inverter 60 or the like. At this time, as shown by the broken line arrow, the abnormality detection unit 40 acquires the high select terminal voltage Va while switching ON / OFF of the power supply relay 31, the reverse connection relay 32, the motor relay 71-73, and the inverter MOS 61-66. .. In FIG. 2, the abnormality detection unit 40 includes a pre-driver function of applying a gate voltage to each relay and inverter MOS. The initial check is preferably performed under conditions where the motor rotation speed is low and is not affected by the counter electromotive voltage, and the initial check of each step such as checking the motor relay open abnormality is that the rotation speed is less than the predetermined rotation speed. May be added to the prerequisites of.

Next, with reference to FIG. 3, the steps of the initial check of the first embodiment will be described in order. FIG. 3 shows the name, precondition, abnormality determination condition, and target failure of each step (“STEP” in the figure). The voltage of the precondition and the threshold values A to H described in the column of the abnormality determination condition are threshold values appropriately set based on the circuit constant such as resistance and the voltage drop. Among them, the threshold values E, F, G, and H used in steps 3 to 6 are set to be intermediate values between the normal voltage and the abnormal voltage shown in FIG. Hereinafter, the description of the names of "voltage after relay Vpig" and "high select terminal voltage Va" will be omitted as appropriate, and will be simply described as "Vpig" and "Va".

The initial check is carried out in order from step 1 to step 6, and if it is determined to be normal in each step, the process proceeds to the next step. That is, step 2 and subsequent steps are carried out on the premise that the failure to be checked in the previous steps is normal. Steps 1, 2, 3 and 6 having only numbers are common to the second embodiment, and steps 4A and 5A having an "A" at the end are steps peculiar to the first embodiment. When an abnormality is detected in any of the steps, an abnormality notification to another ECU of the vehicle or an abnormality alarm to the driver may be performed.

<Step 1: Abnormal precharge function>
Step 1 is carried out under the precondition that the power supply relay 31 is ON, the reverse connection relay 32 and each phase motor relay 71-73 are OFF, each phase upper and lower MOS 61-66 is OFF, and “IG voltage> threshold value A”. Although not shown in the present application, the IG voltage is, for example, a voltage applied to the control circuit of the precharge circuit referred to in FIG. 1 of Patent Document 1. The target failure is a ground fault after the relay, and the abnormality determination condition is “Vpig> threshold value B”. If it is determined to be normal, an appropriate precharge voltage for carrying out step 2 is applied to the circuit.

<Step 2: Check for abnormalities in power relays and reverse relays>
Step 2 is carried out, for example, by the method described in Japanese Patent No. 531233.

<Step 3: Motor relay short circuit error>
Step 3 is carried out under the preconditions that the power supply relay 31 is ON, the reverse connection relay 32 and each phase motor relay 71-73 are OFF, each phase upper and lower MOS 61-66 is OFF, and "Vpig> threshold C". The target failure is a short circuit of the motor relay 71-73 of one phase or more, or a short circuit of the upper MOS 61-63 of one phase or more, and the abnormality determination condition is “Va> Vpig × threshold value E”.

<Step 4A: # Phase detection circuit short circuit error>
The "# phase" in the columns of steps 4A and 5A means "U phase, V phase, W phase". The # phase monitor diode is referred to as "D #". Steps 4A and 5A are carried out three times for each phase. For the upper and lower MOSs of each phase of the prerequisite, when the lower MOS or upper MOS of a certain # phase is "ON", the other MOSs are OFF.

Step 4A is carried out under the preconditions that the power supply relay 31 is ON, the reverse connection relay 32 and each phase motor relay 71-73 are OFF, the # phase lower MOS is ON, and "Vpig> threshold C". The target failure is a short circuit of the # phase monitor diode D #, and the abnormality determination condition is “Va <Vpig × threshold value F”.

<Step 5A: # Phase detection circuit open error>
Step 5A is performed under the preconditions that the power supply relay 31 is ON, the reverse connection relay 32 and each phase motor relay 71-73 are OFF, the #phase MOS is ON, and "Vpig> threshold C". The target failure is the opening of the # phase monitor diode D #, and the abnormality determination condition is “Va <Vpig × threshold value G”.

<Step 6: Motor relay open error>
Step 6 is carried out under the precondition that the power supply relay 31 is ON, the reverse connection relay 32 and each phase motor relay 71-73 are ON, each phase upper and lower MOS 61-66 is OFF, and "Vpig> threshold value D". The threshold D for Vpig in step 6 is different from the threshold C for steps 3, 4A, and 5A because the reverse relay is OFF and the voltage is set in consideration of the voltage drop of the reverse relay. The target failure is the opening of the all-phase motor relay 71-73 or the short circuit of the lower MOS 64-66 of one or more phases, and the abnormality determination condition is "Va <Vpig × threshold value H".

Subsequently, FIGS. 4 and 5 are referred to. FIG. 4 shows whether or not the failure mode of open or short failure of each part in the initial check of FIG. 3 can be detected, the step number when the failure mode can be detected, and the high select terminal voltage Va at the time of normal and abnormal. Vα1, Vα2, Vβ1, and Vβ2 are calculated by the following equations (1) to (4). Vf in the formulas (3) and (4) indicates the voltage drop due to the monitoring diodes Du, Dv, and Dw.

Assuming "Rp, Ru, Rd ≠ 0", the relationship of "Vα1> Vα2" and "Vβ1> Vβ2" is self-evident. However, the magnitude relationship between Vα1 and Vα2 and Vβ1 and Vβ2 is not determined by the value of Vf with respect to Vpig. Therefore, in the first embodiment, the monitoring diodes Du, Dv, and Dw are selected to have a voltage drop Vf such that “Vα1> Vβ2> Vα2”.

Vα2 is a voltage at which the post-relay voltage Vpig is divided by the positive side detection resistor Ru and the negative side detection resistor Rd in a state where no current flows from the monitor diodes Du, Dv, and Dw during normal step 3. be. The same applies to the state where the #phase lower MOS is turned on in step 4A.

Vβ1 is the voltage at the gathering point A in a state where a current flows through the #phase MOS and the #phase monitoring diode D # at the normal time of step 5A. Assuming that the voltage drop Vf due to the monitor diode D # is sufficiently smaller than the voltage drop due to the positive side detection resistor Ru, Vβ1 is a value obtained by subtracting Vf from Vpig.

As shown in the middle part of FIG. 5, the normal Va of step 6 is represented by a circuit including a pull-up resistor Rp, a monitor diode Du, a positive side detection resistor Ru, and a negative side detection resistor Rd. However, since the calculation becomes complicated, it is considered that the Va of the middle circuit in FIG. 5 is larger than Vβ2, which is the Va of the lower circuit, and smaller than Vα1 which is the Va of the upper circuit. Vβ2 in the lower circuit is a voltage at which Vβ1 is divided by the pull-up resistor Rp and the negative side detection resistor Rd.

In FIG. 4, Va in the column marked with “*” indicates a value approximated based on the relationship in FIG. From the viewpoint of reliably detecting an abnormality, the normal Va in step 6 is approximated by the maximum Vα1. The Va at the time of the abnormality in step 3 for checking the motor relay open abnormality is approximated by Vβ2 on the minimum side.

In the actual design, it is preferable that the resistors Rp, Ru, and Rd are set so as to secure the difference in Va between the normal state and the abnormal state as much as possible. As an example, assuming that Rp = 1.3 kΩ, Ru = 10 kΩ, and Rd = 10 kΩ, Vα1, Vα2, and Vβ2 are expressed as follows.
Vα1 ≒ Vpig × 0.90
Vα2 ≒ Vpig × 0.50
Vβ2 ≒ (Vpig-Vf) × 0.88

The values between the normal Va and the abnormal Va calculated in this way are set as the thresholds E to H in FIG. Since the open failure of the MOS 64-66 under the inverter cannot be detected by the initial check of the first embodiment, it is preferable to detect it during normal control. In this embodiment, assuming that the ON circuits of the reverse connection relay and the motor relay are common, the reverse connection relay and the motor relay are configured so that the ON or OFF states are the same. For example, steps 2 to 5 are reverse connection. An abnormality may be checked by turning off the relay.

When the terminal voltage of each phase is detected for abnormality detection, there is a problem that the number of terminal voltage detections increases. In the first embodiment, by detecting an abnormality based on the high select terminal voltage Va, the number of detected terminal voltages for detecting a three-phase abnormality can be unified. Therefore, the number of parts for detecting an abnormality can be reduced and the circuit can be miniaturized. This is particularly effective for electric power steering devices, which have strict restrictions on mounting space.

Further, the high select terminal voltage detection unit 44 of the first embodiment is based on the highest voltage among the three-phase voltages obtained via the monitor diodes Du, Dv, and Dw of the inverter 60. Detects site abnormalities. In the prior art of Patent Document 1, which detects an abnormality based on the neutral point voltage, as the number of phases to be checked increases, the voltage difference between the normal state and the abnormal state becomes smaller, so that the abnormality detection accuracy decreases. There is a risk. On the other hand, in the present embodiment of abnormality detection using the high select terminal voltage, it is possible to secure the same abnormality detection accuracy regardless of the number of phases of the inverter.

(Second Embodiment)
The second embodiment will be described with reference to FIGS. 6 to 8. As shown in FIG. 6, the ECU 102 of the second embodiment differs from the ECU 101 of the first embodiment only in that the positive side detection resistor Ru is not provided. The basic configuration for detecting an abnormality in the inverter MOS61-66 or the like based on the high select terminal voltage Va of the set point A, which is the connection point between the cathodes of the diodes Du, Dv, and Dw for each phase monitor, is the first embodiment. Is similar to. In the second embodiment, for example, the resistance values of the pull-up resistor Rp and the negative side detection resistor Rd are both set to 4.7 kΩ.

7 and 8 correspond to FIGS. 3 and 4 of the first embodiment. In the second embodiment, of the initial check steps shown in FIG. 7, steps 4B and 5B are different from those in the first embodiment. Regarding the abnormality determination conditions of steps 3 and 6 in FIG. 7, only the threshold symbol is shown in FIG. different. As the threshold value I and the threshold value L, the same values as the threshold value E and the threshold value H of the first embodiment may be used, respectively.

<Step 4B: #Aigami MOS open abnormality>
Similar to the first embodiment, steps 4B and 5B are carried out three times for each phase. For the upper and lower MOSs of each phase of the prerequisite, when the lower MOS or upper MOS of a certain # phase is "ON", the other MOSs are OFF.

Step 4B is carried out under the preconditions that the power supply relay 31 is ON, the reverse connection relay 32 and each phase motor relay 71-73 are OFF, the #phase MOS is ON, and "Vpig> threshold C". The target failure is the opening of the #phase MOS or the opening of the #phase monitoring diode D #, and the abnormality determination condition is “Va <Vpig × threshold value J”.

<Step 5B: #Phase MOS open abnormality>
Step 5B is performed under the preconditions that the power supply relay 31 is ON, the reverse connection relay 32 and each phase motor relay 71-73 are OFF, the # phase lower MOS is ON, and "Vpig> threshold C". The target failure is the opening of the #phase lower MOS, and the abnormality determination condition is “Va> Vpig × threshold value K”.

Subsequently, FIG. 8 is referred to. In the second embodiment without the positive side detection resistor Ru, the Va in the normal state and the abnormal state is only three values of Vβ1, Vβ2, and GND. Assuming "Rp, Rd ≠ 0", the relationship of "Vβ1> Vβ2" is self-evident.

Vβ1 is the voltage at the gathering point A in a state where a current flows through the #phase MOS and the #phase monitoring diode D # at the normal time of step 4B. Vβ2 is the voltage at the gathering point A in a state where a current flows through the pull-up resistor Rp and the # phase monitor diode D # when the step 5B is normal. Vβ2 is a voltage at which Vβ1 is divided by the pull-up resistor Rp and the negative side detection resistor Rd.

The values between the normal Va and the abnormal Va calculated in this way are set as the thresholds I to L in FIG. 7. Since short-circuit failures of the monitor diodes Du, Dv, and Dw cannot be detected by the initial check of the second embodiment, it is preferable to detect them during normal control. In the second embodiment, the configuration is simpler than that in the first embodiment, and almost the same effects as those in the first embodiment can be obtained. Further, also in the second embodiment, in steps 2 to 5, the reverse connection relay may be turned off and an abnormality check may be performed.

(Third Embodiment)
The third embodiment will be described with reference to FIG. The ECU 103 of the third embodiment is applied to a motor 802 having two sets of three-phase windings 81-83. In the ECU 103, two inverters 601 and 602 for supplying electric power to each of the three-phase windings 81-83 are connected in parallel after the power supply relay 31 and the reverse connection relay 32. The inverters 601 and 602 are provided with the same pull-up resistors Rp and monitor diodes Du, Dv, and Dw as in the first and second embodiments. Further, motor relays 71-73 of each phase are provided in the inverters 601 and 602. Since the components of the inverters 601 and 602 are substantially the same, they are not distinguished and have the same reference numerals. Further, the illustration of the ON / OFF signal from the abnormality detection unit 40 to the relays 31, 32, 71-73 and the switch element 61-66 is omitted.

As shown in FIG. 9, two inverters 601 and 602 connected in parallel, two pull-up resistors Rp, two sets of each phase monitoring diodes Du, Dv, Dw, and two sets of each phase motor relay 71- A group of units including 73 is defined as a "parallel power conversion unit". The abnormality detection device of the third embodiment has one parallel power conversion unit 100. Here, the cathodes of the two sets of each phase monitoring diodes Du, Dv, and Dw are connected to one gathering point A. That is, there is a one-to-one correspondence between the parallel power conversion unit and the set point A. Further, in the present embodiment, one set of the power supply relay 31, the reverse connection relay 32, and the smoothing capacitor 35 of the input unit and one parallel power conversion unit correspond to each other.

The number of inverters connected in parallel in one parallel power conversion unit may be three or more. In that case, the number of pull-up resistors Rp corresponding to the number of inverters, each phase monitoring diode Du, Dv, Dw, and each phase Motor relays 71-73 are provided. In another embodiment, the parallel power conversion unit may not include the motor relays 71-73. Further, pull-up resistors Rp may be provided in two or more phases of each inverter.

One high-select terminal voltage detection unit 44 and one abnormality detection unit 40 are provided for one parallel power conversion unit 100. Further, depending on the detection configuration of the high select terminal voltage detection unit 44, in the configuration based on the first embodiment, a set of a positive side detection resistor Ru and a negative side detection resistor Rd are provided. Instead of this, in the configuration based on the second embodiment, there may be no positive side detection resistor Ru, and only the negative side detection resistor Rd may be provided.

In the third embodiment, by configuring the motor 802 with two three-phase windings 81-83, the output torque per one three-phase winding becomes (1/2) of the whole. Therefore, the current rating of the MOS 61-66 of each of the inverters 601 and 602 can be reduced, and the load and heat generation can be dispersed. In addition, when each phase of the upper and lower arms of one inverter is composed of two MOSs connected in parallel, variation in characteristics between the MOSs tends to be a problem, but by connecting the entire inverter in parallel, the effect of variation can be affected. Can be reduced.

If the terminal voltage of each phase is detected for abnormality detection in such a parallel connection configuration, there is a problem that the number of terminal voltage detections increases and the circuit scale increases. That is, although the inverter unit itself is miniaturized by parallelization, the terminal voltage detection unit is rather large. In that respect, in the third embodiment, since the number of terminal voltage detections can be one for one parallel power conversion unit 100, it is possible to avoid an increase in the circuit scale.

Further, the high select terminal voltage detection unit 44 of the third embodiment is based on the highest voltage among the six-phase voltages obtained via the monitoring diodes Du, Dv, and Dw of the two inverters 601 and 602. , Detects an abnormality in any part of the parallel power conversion unit 100. In the prior art of Patent Document 1, which detects an abnormality based on the neutral point voltage, as the number of phases to be checked increases, the voltage difference between the normal state and the abnormal state becomes smaller, so that the abnormality detection accuracy decreases. There is a risk. On the other hand, in the present embodiment of abnormality detection using the high select terminal voltage, it is possible to secure the same abnormality detection accuracy regardless of the number of inverters connected in parallel in one unit.

(Fourth Embodiment)
The fourth embodiment will be described with reference to FIG. The fourth embodiment is applied to a motor 804 having four sets of three-phase windings 81-83, and the parallel power conversion unit of the third embodiment shown in FIG. 9 is further two parallel to one battery 15. It is connected. The codes of the two parallel power conversion units are referred to as "100" and "200". The reference numerals of the components in the parallel power conversion units 100 and 200 are the same as those in FIG. 9, and are omitted.

Corresponding to the first parallel power conversion unit 100, the post-relay voltage detection unit 431 that detects the post-relay voltage Vpig1 by dividing the voltage at the connection point P1, and the high-select terminal voltage that detects the high-select terminal voltage Va1 at the gathering point A1. A detection unit 441 and an abnormality detection unit 401 are provided. Further, corresponding to the second parallel power conversion unit 200, the post-relay voltage detection unit 432 that detects the post-relay voltage Vpig2 by the voltage division of the connection point P2, and the high-select that detects the high-select terminal voltage Va2 at the gathering point A2. A terminal voltage detection unit 442 and an abnormality detection unit 402 are provided.

For example, it is assumed that an abnormality is detected in any of the upper and lower MOS 61-66 of each phase of the inverters 601 and 602 in the first parallel power conversion unit 100. At this time, the abnormality detection unit 401 turns off each phase MOS 61-66 of all the inverters 601 and 602 in the first parallel power conversion unit 100. If no abnormality is detected in the second parallel power conversion unit 200, after the initial check is completed, the ECU 104 starts driving the motor 804 using only the second parallel power conversion unit 200 as a function of the motor control device. ..

If any of the upper and lower MOS 61-66 of each phase is out of order, the circuit may overheat due to overcurrent, or the power conversion operation as instructed may not be possible. Therefore, by configuring the plurality of parallel power conversion units 100 and 200 to be redundantly provided, when an abnormality is detected in some of the units, the ECU 104 stops the operation of the abnormal unit and is a normal unit. The motor 804 can be driven only by itself. As described above, one parallel power conversion unit that functions as one unit of driving in the redundant configuration corresponds to "one system" in the so-called multiple system configuration.

In the case of a failure of the power supply relay 31, the reverse connection relay 32, or the motor relay 71-73, there is a possibility that the energization cannot be quickly cut off when an overcurrent occurs while the motor is being driven. Further, in the case of a failure of the monitor diodes Du, Dv, and Dw, the initial check step is not normally executed, and there is a possibility that the failure of the MOS or the relay cannot be detected. Therefore, even if an abnormality is detected in any of the relays 31, 32, 71-73 or the monitoring diodes Du, Dv, Dw, each phase MOS 61- of all the inverters 601 and 602 in the parallel power conversion unit is detected. 66 may be turned off.

Further, the abnormality detection unit 401 and the abnormality detection unit 402 may mutually notify the abnormality detection information of the parallel power conversion units 100 and 200 as shown by the broken line arrows. As a result, the ECU 104 can appropriately select the drive conditions according to the situation, such as switching between the drive mode of one unit and the drive mode of two units as a function of the motor control device.

(Other embodiments)
(A) In the initial check of the above embodiment, in addition to the inverter upper and lower MOS61-66, the power supply relay 31, the reverse connection relay 32, the motor relay 71-73, and the monitoring diodes Du, Dv, and Dw are checked in a series of steps. NS. However, checks other than the inverter upper and lower MOS 61-66 may be performed in advance by another process, for example.

(B) The multi-phase rotating machine to be controlled according to the present invention is not limited to the steering assist motor of the electric power steering device, and may be a motor for other purposes. In particular, the present invention is effective in a system in which the mounting space of the abnormality detection device is restricted and high-precision initial check is required.

As described above, the present invention is not limited to such embodiments, and can be implemented in various embodiments without departing from the spirit of the invention.

10 (101-104) ... ECU (abnormality detection device, motor control device),
15 ・ ・ ・ Battery (DC power supply),
40 (401, 402) ... Abnormality detection unit,
44 (441, 442) ... High select terminal voltage detector,
60 (601, 602) ... Inverter (power converter),
61-66 ・ ・ ・ MOS (switch element),
80 (801, 802, 804) ... Motor (multi-phase rotating machine),
Du, Dv, Dw ... Monitor diode,
Rd: Negative side detection resistor, Rp: Pull-up resistor.

Claims (6)

A plurality of switch elements (61-66) arranged on the positive side and the negative side of the DC power supply (15) are connected by a bridge, and the power of the DC power supply is converted to convert each of the multi-phase rotating machines (80). The power converter (60) supplied to the phase winding and
A pull-up resistor (Rp) that connects one or more phase windings of the multi-phase rotating machine to the positive side of the DC power supply, and
Arm-to-arm connection points (Nu, Nv, Nw) that are connection points between a switch element arranged on the positive side of the DC power supply of each phase and a switch element arranged on the negative side of the DC power supply in the power converter. Multiple monitoring diodes (Du, Dv, Dw) with an anode connected to the
A negative side detection resistor (Rd) connecting a set point (A), which is a connection point between the cathodes of the monitor diodes of each phase, and the negative side of the DC power supply,
A high-select terminal voltage detection unit (44) that detects the high-select terminal voltage (Va), which is the voltage at the gathering point, and
With the threshold voltage set based on the input voltage (Vpig) from the DC power supply, the voltage drop (Vf) by the monitoring diode, the resistance value of the pull-up resistance, and the resistance value of the negative side detection resistance. , An abnormality detection unit (40) that compares with the high select terminal voltage and detects at least an abnormality of the power converter.
Anomaly detection device. Further, a positive side detection resistor (Ru) for connecting the gathering point and the positive side of the DC power supply is provided.
The abnormality detection device according to claim 1, wherein the abnormality detection unit further sets the threshold voltage based on the resistance value of the positive side detection resistor. The power converters (601, 602) that supply power to at least a part of the plurality of multi-phase windings of the plurality of multi-phase windings of the multi-phase rotating machine.
A plurality of the pull-up resistors provided in each power converter,
The monitoring diode provided in each phase of each power converter and having its cathode connected to one of the gathering points.
If a group of units including is defined as a parallel power conversion unit (100, 200),
With one or more of the parallel power conversion units
The parallel power conversion unit is provided with one high-select terminal voltage detection unit having the corresponding detection resistor and one abnormality detection unit.
The abnormality according to claim 1 or 2, wherein in each of the parallel power conversion units, the abnormality detection unit detects at least an abnormality of each of the power converters included in the parallel power conversion unit based on the voltage at the gathering point. Detection device. The abnormality according to claim 3, further comprising the plurality of parallel power conversion units (100, 200), the plurality of high select terminal voltage detection units (441, 442), and the plurality of abnormality detection units (401, 402). Detection device. The abnormality detection unit that has detected an abnormality in any one or more of the power converters in the corresponding parallel power conversion unit switches elements of each phase of all the power converters in the parallel power conversion unit. The abnormality detection device according to claim 4, which is turned off. The abnormality detection device according to any one of claims 1 to 5, which is used for initial checking of a device that controls driving of a steering assist motor as a multi-phase rotating machine in an electric power steering device of a vehicle.

Images