JP2022185373A - Current detector and motor controller - Google Patents

Abstract

To solve such a problem that an abnormality in a current detection value of one phase cannot be accurately detected while a motor is being driven.SOLUTION: A current detector comprises: a current ratio calculation unit which calculates a current ratio being a ratio of the sum of current detection values of other two phases to a current detection value of one phase in the three-phase AC current output to a three-phase motor while the three-phase motor is being driven; and a current value abnormality determination unit which determines that each current detection value of the three-phase AC current is normal when the current ratio calculated by the current ratio calculation unit is within a prescribed range, and determines that the current detection value of the one phase is abnormal when the current ratio is not included in the prescribed range.SELECTED DRAWING: Figure 1

Description

The present invention relates to a current detection device and a motor control device.

The value of the three-phase AC current output to the three-phase motor is detected by a current detection section including a current sensor or the like. In order to accurately control a three-phase motor, it is necessary to accurately detect whether there is an abnormality in the current detection value detected by the current detection unit.

In Patent Document 1, if the absolute value of any one of the currents iu, iw, and iv detected by the current sensor is equal to or greater than a specified value α immediately after the travel permission switch of the vehicle is switched from off to on, the current It is determined that the output value of the sensor is offset by a predetermined amount, and if the absolute value of the sum of the currents iu, iw, and iv is larger than the predetermined value β, the true value is set to a predetermined value. A control device for a rotating machine is disclosed that determines that a multiplied gain is abnormal.

JP 2016-013040 A

In the device described in Patent Document 1, it was not possible to accurately detect that the current detection value of one of the three phases is abnormal during driving of the motor.

The current detection device according to the present invention detects a ratio of the sum of the current detection values of one phase to the current detection value of the other two phases among the three-phase alternating currents output to the three-phase motor while the three-phase motor is being driven. and a current ratio calculation unit for calculating a current ratio, and when the current ratio calculated by the current ratio calculation unit is within a predetermined range, it is determined that each current detection value of the three-phase alternating current is normal. and a current value abnormality determination unit that determines that the current detection value of the one phase is abnormal when the current ratio is not included in the predetermined range.
A motor control device according to the present invention includes a current detection unit that detects a three-phase alternating current being output to a three-phase motor, and a current detection value of one phase of the three-phase alternating current while driving the three-phase motor. and a current ratio calculator for calculating a current ratio that is a ratio of the sum of the current detection values of the other two phases to the current detection when the current ratio calculated by the current ratio calculator is within a predetermined range. each current detection value of the three-phase alternating current detected by the section is determined to be normal, and when the current ratio is not included in the predetermined range, it is determined that the one-phase current detection value is abnormal and a current value abnormality determination unit.

According to the present invention, it is possible to accurately detect that the current detection value of one phase is abnormal during driving of the motor.

1 is a circuit configuration diagram of a motor control device according to a first embodiment; FIG. It is a circuit block diagram of a power inverter circuit. (A) and (B) are graphs showing relationships between current detection values and current ratios. 4 is a flowchart showing processing of a current ratio calculator; 5 is a flowchart showing processing of a current value abnormality determination unit; FIG. 7 is a circuit configuration diagram of a motor control device according to a second embodiment; 9 is a flowchart showing processing of a current correction unit according to the second embodiment; FIG. 11 is a circuit configuration diagram of a motor control device according to a third embodiment; It is a flow chart which shows processing of a current ratio operation part concerning a 3rd embodiment. It is a flow chart which shows processing of a current amendment part concerning a 3rd embodiment.

Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are examples for explaining the present invention, and are appropriately omitted and simplified for clarity of explanation. The present invention can also be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

In the following description, the processing shown in the flowchart may be described, but this processing is performed by executing a program, and the program is executed by a processor (eg, CPU, GPU) to Since processing is performed using storage resources (such as memory) and/or interface devices (such as communication ports) as appropriate, the subject of processing may be a processor. Similarly, a main body of processing executed by executing a program may be a controller having a processor, a device, a system, a computer, or a node. The subject of the processing performed by executing the program may be an arithmetic unit, and may include a dedicated circuit (for example, FPGA or ASIC) that performs specific processing.

A program may be installed on a device, such as a computer, from a program source. The program source may be, for example, a program distribution server or a computer-readable storage medium. When the program source is a program distribution server, the program distribution server may include a processor and storage resources for storing the distribution target program, and the processor of the program distribution server may distribute the distribution target program to other computers. Also, in the following description, two or more programs may be implemented as one program, and one program may be implemented as two or more programs.

[First embodiment]
FIG. 1 is a circuit configuration diagram of a motor control device 100 according to the first embodiment.
Motor control device 100 converts DC power obtained from DC power supply 200 into AC power to drive motor 300 . A DC power supply 200 is configured by a secondary battery or the like, and supplies DC power. The motor 300 is a three-phase electric motor having windings for three phases inside. The motor 300 is provided with an angle sensor 301 such as a resolver that detects the rotation angle of the rotor. The motor 300 is mounted on the vehicle and functions as a drive source for the vehicle during power running and as a generator during regeneration.

The motor control device 100 includes a power conversion circuit 101 , a main control section 102 , a current detection section 103 , an angle calculation section 104 , a current ratio calculation section 105 and a current value abnormality determination section 106 . A current detection device for detecting an abnormality in the current detection value is composed of at least the current ratio calculation section 105 and the current value abnormality determination section 106 .

The current detection unit 103 detects the value of alternating current output from the power conversion circuit 101 . The current detection unit 103 includes a current sensor (not shown) and an A/D conversion circuit that converts analog information output from the current sensor into digital information. Then, the current sensors placed in each of the UVW phases measure the alternating current Iu flowing through the U phase, the alternating current Iv flowing through the V phase, and the alternating current Iw flowing through the W phase. The information is converted into digital information by an A/D conversion circuit provided corresponding to each phase, and current detection values Iu_s, Iv_s, and Iw_s are output to main control section 102 and current ratio calculation section 105 .

The angle calculation unit 104 receives angle information of the rotor from the angle sensor 301 arranged in the motor 300, calculates the electrical angle θe_s using this, and outputs it to the main control unit 102 and the current value abnormality determination unit 106. do.

The main control unit 102 communicates with an electronic control device (not shown) provided outside the motor control device 100 and receives the target torque of the motor 300 from this electronic control device. The current detection values Iu_s, Iv_s, and Iw_s from the current detection unit 103 and the electrical angle θe_s from the angle calculation unit 104 are input to the main control unit 102 .

Then, the main control unit 102 calculates a target current value to be supplied to the motor 300 based on the target torque. This target current value is represented by, for example, a d-axis current target value and a q-axis current target value. Specifically, the d-axis current detection value and the q-axis current detection value to calculate Then, the deviation between the d-axis current target value that is the target current value and the d-axis current detection value that is the detection value, and the deviation between the q-axis current target value that is the target current value and the q-axis current detection value that is the detection value is used to perform feedback control to determine the drive signal to be output to the power conversion circuit 101 . Further, the main control unit 102 receives abnormality information from the current value abnormality determination unit 106, and performs control corresponding to the input abnormality information, which will be described later in detail.

The power conversion circuit 101 includes a three-phase upper and lower arm series circuit composed of switching elements, and performs switching operations of the switching elements based on drive signals output from the main control unit 102 . During power running, the DC power supplied from the DC power supply 200 is converted into three-phase AC power to drive the motor 300 . Also, during regeneration, the three-phase AC power is converted into DC power to charge the DC power supply 200 .

Based on the current detection values Iu_s, Iv_s, and Iw_s input from the current detection unit 103, the current ratio calculation unit 105 calculates the current ratios Gu and Gv shown in the following equations (1), (2), and (3). , Gw. This calculation is a calculation of dividing the sum of the current detection values of the two phases by the current detection value of the other phase and multiplying the result by -1.

式（１）では、Ｖ相とＷ相の電流検出値Iv_s、Iw_sの和をＵ相の電流検出値Iu_sで除算して－１倍したものを電流比Ｇｕとする。以下、Ｕ相を基準とする電流比Ｇｕと称する。

In equation (1), the current ratio Gu is obtained by dividing the sum of the V-phase and W-phase current detection values Iv_s and Iw_s by the U-phase current detection value Iu_s and multiplying the result by -1. Hereinafter, it will be referred to as a current ratio Gu based on the U phase.

式（２）では、Ｕ相とＷ相の電流検出値Iu_s、Iw_sの和をＶ相の電流検出値Iv_sで除算して－１倍したものを電流比Ｇｖとする。以下、Ｖ相を基準とする電流比Ｇｖと称する。

In equation (2), the current ratio Gv is obtained by dividing the sum of the U-phase and W-phase current detection values Iu_s and Iw_s by the V-phase current detection value Iv_s and multiplying the result by -1. Hereinafter, it will be referred to as a current ratio Gv based on the V phase.

式（３）では、Ｕ相とＶ相の電流検出値Iu_s、Iv_sの和をＷ相の電流検出値Iw_sで除算して－１倍したものを電流比Ｇｗとする。以下、Ｗ相を基準とする電流比Ｇｗと称する。

In equation (3), the current ratio Gw is obtained by dividing the sum of the U-phase and V-phase current detection values Iu_s and Iv_s by the W-phase current detection value Iw_s and multiplying the result by -1. Hereinafter, this is referred to as a current ratio Gw based on the W phase.

In this way, the current ratio calculation unit 105 calculates the current detection value of one phase of the three-phase alternating current output to the motor 300 while the three-phase motor 300 is being driven. Calculate the current ratio, which is the ratio of the sums. Current ratio calculation section 105 then outputs the calculated current ratios Gu, Gv, and Gw to current value abnormality determination section 106 .

The current value abnormality determination unit 106 receives the current ratios Gu, Gv, and Gw from the current ratio calculation unit 105 and the electrical angle θe_s from the angle calculation unit 104 . The current value abnormality determination unit 106 monitors the current ratios Gu, Gv, and Gw, and determines that the three current ratios Gu, Gv, and Gw are 1 within a period in which the electrical angle θe_s changes by 180 degrees (a constant electrical angle range). If it can be regarded as constant (within a predetermined range), it is determined as normal. Also, when only one current ratio takes a constant value within a period of 180° change (a constant electrical angle range), and the other two current ratios do not take constant values (not included in the predetermined range), A phase with a constant current ratio is determined to be an abnormal phase. That is, when the current ratio calculated by the current ratio calculation unit 105 is within a predetermined range, the current value abnormality determination unit 106 determines that each current detection value of the three-phase alternating current is normal, and the current ratio is If it is not within the predetermined range, it is determined that the current detection value of one phase is abnormal. The determined abnormality information is output to the main control unit 102 .

When failure information is input, the main control unit 102 performs control corresponding to the input failure information. Then, failure information indicating which phase's current detection value is abnormal is output to an external electronic control device. When failure information is input, the main control unit 102 may not be able to accurately control the motor 300 if it continues to control the motor 300 even though the current detection values Iu_s, Iv_s, and Iw_s are in an abnormal state. . Therefore, the main control unit 102 stops the operation of the power conversion circuit 101 . For example, when the current value abnormality determination unit 106 determines that the current detection values Iu_s, Iv_s, and Iw_s are abnormal, the main control unit 102 turns off all the switching elements of the power conversion circuit 101, or A drive signal is output to turn on all the switching elements of the upper arm or lower arm. For example, by turning on all the switching elements of the upper arm or the lower arm, the windings of the motor 300 are short-circuited, and the motor 300 is rotated by an external force even though the function of the power conversion circuit 101 is stopped. In this case, the smoothing capacitor is prevented from being charged by the induced voltage of the motor 300. - 特許庁

FIG. 2 is a circuit configuration diagram of the power conversion circuit 101. As shown in FIG.
The power conversion circuit 101 has a UVW-phase upper and lower arm series circuit. The U-phase upper and lower arm series circuit consists of a U-phase upper arm switching element Tuu, a U-phase upper arm diode Duu, a U-phase lower arm switching element Tul and a U-phase lower arm diode Dul. The V-phase upper and lower arm series circuit includes a V-phase upper arm switching element Tvu and a V-phase upper arm diode Dvu, and a V-phase lower arm switching element Tvl and a V-phase lower arm diode Dvl. The W-phase upper and lower arm series circuit includes a W-phase upper arm switching element Twu and a W-phase upper arm diode Dwu, and a W-phase lower arm switching element Twl and a W-phase lower arm diode Dwl.

The upper arm includes a U-phase upper arm switching element Tuu and a U-phase upper arm diode Duu, a V-phase upper arm switching element Tvu and a V-phase upper arm diode Dvu, a W-phase upper arm switching element Twu and a W-phase upper arm diode Dwu. and The lower arm includes a U-phase lower arm switching element Tul and a U-phase lower arm diode Dul, a V-phase lower arm switching element Tvl and a V-phase lower arm diode Dvl, a W-phase lower arm switching element Twl and a W-phase lower arm diode Dwl. and These switching elements are hereinafter referred to as switching elements 121 . The switching element 121 has shown an example of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), but may be an IGBT (Insulated Gate Bipolar Transistor) or another element.

The power conversion circuit 101 is supplied with DC power from a DC power supply 200 via positive electrodes B+ and negative electrodes B− of the busbar. A smoothing capacitor (not shown) is connected between the positive electrode B+ and the negative electrode B- of the bus bar. A drive signal 102U is input from the main controller 102 to the gate electrode of the switching element 121 of the upper arm. A drive signal 102L is input from the main controller 102 to the gate electrode of the switching element 121 of the lower arm. AC wiring is derived from each upper and lower arm connection point of the UVW phase upper and lower arm series circuit, and is connected to the winding of the motor 300 . When the current value abnormality determination unit 106 determines that the current detection values Iu_s, Iv_s, and Iw_s are abnormal, the main control unit 102 turns off all the switching elements 121 of the power conversion circuit 101 or turns off all the switching elements 121 . A drive signal is output to turn on all the switching elements 121 of the arm or lower arm.

FIGS. 3(A) and 3(B) are graphs showing the relationship between current detection values Iu_s, Iv_s, Iw_s and current ratios Gu, Gv, Gw. FIG. 3A shows current detection values Iu_s, Iv_s, and Iw_s, and FIG. 3B shows current ratios Gu, Gv, and Gw. Both horizontal axes are electrical angles. The current detection values Iu_s, Iv_s, and Iw_s are normal from an electrical angle of 0 to 360 degrees, and the amplitude of the U-phase current detection value Iu_s is excessive after an electrical angle of 360 degrees. explain.

As shown in FIG. 3A, from 0 degrees to 360 degrees in electrical angle, the U-phase current detection value Iu_s indicated by the dotted line with small intervals between dots, and the V-phase current detected by the dotted line with medium intervals The detected value Iv_s and the W-phase current detected value Iw_s indicated by the dotted line with large intervals between the points have the same amplitude and the electrical angles are shifted by 120 degrees from each other.

As shown in FIG. 3B, from 0 degrees to 360 degrees in electrical angle, the current ratio Gu based on the U phase indicated by the dotted line with small dot spacing, and the V phase indicated by the dotted line with medium spacing , and the current ratio Gw based on the W-phase indicated by the dotted line with a large distance between the dots are all 1. In other words, if the current detection values Iu_s, Iv_s, and Iw_s are normal, the current ratios Gu, Gv, and Gw based on Equations (1), (2), and (3) are all 1. That is, if the current detection values Iu_s, Iv_s, and Iw_s are normal, the current value obtained by multiplying the sum of the two-phase current detection values by -1 and the other one-phase current detection value have the same phase and amplitude. Therefore, the calculation results of the current ratios Gu, Gv, and Gw are all 1.

Assume that the amplitude of the U-phase current detection value Iu_s becomes excessive at an electrical angle of 360 degrees, as shown in FIG. The current ratios Gu, Gv, and Gw based on the formulas (1), (2), and (3) are, as shown in FIG. Gw fluctuates greatly.

From this, if the calculation results of the current ratios Gu, Gv, and Gw are all 1, the current detection values Iu_s, Iv_s, and Iw_s are normal, and only one of the current ratios Gu, Gv, and Gw is a constant value other than 1. If so, it can be identified that the current detection values Iu_s, Iv_s, and Iw_s of the phase other than 1 are abnormal. In other words, when the current ratios Gu, Gv, and Gw are within a predetermined range, it is determined that the current detection values Iu_s, Iv_s, and Iw_s of the three-phase alternating current are normal, and the current ratios Gu, Gv, and Gw are determined to be normal. If it is not within the predetermined range, it can be determined that the current detection value of the other one phase is abnormal. When one phase is abnormal, the current ratio of the normal phase repeats the same characteristics every 180 degrees of electrical angle. Abnormality is determined by whether or not. If the current detection values Iu_s, Iv_s, and Iw_s are abnormal, the current sensor in the current detection unit 103 or the A/D conversion circuit that A/D converts the analog information output from the current sensor may be malfunctioning. be done.

FIG. 4 is a flowchart showing the processing of the current ratio calculator 105. As shown in FIG. The current ratio calculator 105 executes the process of the flowchart shown in FIG. 4 while the motor 300 is being driven.
In step S401, the current ratio calculator 105 determines whether the current detection values Iu_s, Iv_s, and Iw_s sampled by the current detector 103 have been received. If not received, the process of step S401 is repeated until it is received. When received, the process proceeds to the next step S402.

In step S402, the current ratio calculation unit 105 calculates the current ratios Gu, Gv, and Gw of the current detection values Iu_s, Iv_s, and Iw_s by the formulas (1), (2), and (3) described above, respectively. .
Then, in step S<b>403 , the calculated current ratios Gu, Gv, and Gw are output to current value abnormality determination section 106 . After the processing ends, the processing shown in FIG. 4 is repeated.

The current detection values Iu_s, Iv_s, and Iw_s of the current detection unit 103 are sampled a plurality of times while the electrical angle θe_s of the angle calculation unit 104 changes by 180 degrees. This is because, for example, as shown in FIGS. 3A and 3B, only the current ratio Gu becomes a constant value other than 1, and the current ratios Gv and Gw fluctuate greatly. It is for

FIG. 5 is a flowchart showing the processing of the current value abnormality determination unit 106. As shown in FIG. Current value abnormality determination unit 106 executes the flowchart shown in FIG. 5 while motor 300 is being driven.
In step S501, the current value abnormality determination unit 106 initializes values. That is, the reference electrical angle θ0 is defined as θe_s, and the abnormality counters k, ku, kv, and kw are set to zero.

In step S502, the current value abnormality determination unit 106 stores the current electrical angle θe_s in θn. Then, in step S503, the current value abnormality determination unit 106 obtains the difference between the electrical angle θ0 and the electrical angle θn from the angle calculation unit 104, and determines whether the electrical angle difference is 180 degrees or more. If less than 180 degrees, the process proceeds to step S504. In step S503, the current value abnormality determination unit 106 acquires the electrical angle from the angle calculation unit 104 and determines whether the electrical angle difference is 180 degrees or more. The determination may be made based on a command from the unit 102 indicating that the electrical angle difference is 180 degrees or more.

In step S504, the current value abnormality determination unit 106 determines whether or not the current ratios Gu_n, Gv_n, and Gw_n at the electrical angle θn are 1. Specifically, it is determined whether the conditions of the following expressions (4) to (6) are satisfied. Here, .epsilon. is a value considering an error in calculating the current ratio.

If the conditions of formulas (4) to (6) are not satisfied, the process proceeds to step S505, and 1 is added to the abnormality counter k. If the conditions of formulas (4) to (6) are satisfied, the process proceeds to step S506.
In step S506, the current value abnormality determination unit 106 determines whether the difference from the previous value of the current ratio Gu based on the U phase is within a certain error ΔG, using the following equation (7).

If the difference is greater than the error ΔG, 1 is added to the U-phase abnormality counter ku in step S507.
After that, the process proceeds to step S508, and the current value abnormality determination unit 106 determines whether the difference from the previous value of the current ratio Gv based on the V phase is within a certain error ΔG, using the following equation (8).

If the difference is greater than the error ΔG, 1 is added to the V-phase abnormality counter kv in step S509.
After that, proceeding to step S510, the current value abnormality determination unit 106 determines whether the difference from the previous value of the current ratio Gw based on the W phase is within a certain error ΔG, using the following equation (9).

If the difference is greater than the error ΔG, 1 is added to the W-phase abnormality counter kw in step S511.
Note that the order of steps S506, S508, and S510 is not limited to the order described, and the order may be changed.

After that, the process returns to step S502, and the processing of steps S503 to S511 is performed for the next electrical angle θe_s.
If it is determined in step S503 that the electrical angle difference between the electrical angles .theta.0 and .theta.n is 180 degrees or more, the process proceeds to step S512.

In step S512, the current value abnormality determination unit 106 determines whether the number k of times the three current ratios Gu, Gv, and Gw cannot be considered to be 1 during the period in which the electrical angle changes by 180 degrees is equal to or less than the allowable number of times k′. judge. If it is equal to or less than the permissible number of times k', the process advances to step S513, it is determined to be normal, and the abnormality information F is set to zero. If it is not equal to or less than the allowable number of times k', the process proceeds to step S514.

In step S514, if only the value of the U-phase abnormality counter ku is equal to or less than the allowable number of times k' and the other abnormality counters are greater than the allowable number of times, the current value abnormality determination unit 106 is determined to be abnormal. Then, in the next step S515, the abnormality information F indicating that the U-phase current detection value Iu_s is abnormal is set to 1. If the condition of step S514 is not satisfied, the process proceeds to step S516.

In step S516, if only the value of the V-phase abnormality counter kv is equal to or less than the allowable number of times k' and the other abnormality counters are larger than the allowable number of times, the current value abnormality determination unit 106 is determined to be abnormal. Then, in the next step S517, the abnormality information F indicating that the V-phase current detection value Iv_s is abnormal is set to 2. If the condition of step S516 is not satisfied, the process proceeds to step S518.

In step S518, if only the value of the W-phase abnormality counter kw is equal to or less than the allowable number of times k′ and the other abnormality counters are greater than the allowable number of times, the current value abnormality determination unit 106 is determined to be abnormal. Then, in the next step S519, the abnormality information F indicating that the W-phase current detection value Iw_s is abnormal is set to 3. If the condition of step S518 is not satisfied, the process proceeds to step S520.

In step S520, the current value abnormality determination unit 106 determines that there is an abnormality other than an abnormality in only one of the current detection values Iu_s, Iv_s, and Iw_s of each phase, and sets the abnormality information F indicating this to 4. Abnormalities other than a one-phase-only abnormality are, for example, two-phase, three-phase, and other abnormalities.

After the processing of steps S513, S515, S517, S519, and S520, the process proceeds to step S521. In step S<b>521 , current value abnormality determination section 106 outputs abnormality information F to main control section 102 .

The main control unit 102 that has received the abnormality information F, as described above, when the current value abnormality determination unit 106 determines that the current detection values Iu_s, Iv_s, and Iw_s are abnormal, that is, F=1, When F=2, F=3, and F=4, output a drive signal to turn off all the switching elements 121 of the power conversion circuit 101 or to turn on all the switching elements 121 of the upper arm or the lower arm. do. When F=1, the U-phase current detection value is abnormal. When F=2, the V-phase current detection value is abnormal. When F=3, the W-phase current detection value is abnormal. It outputs failure information indicating that it is to an external electronic control unit. In the case of F=4, failure information indicating that there is an abnormality in the current detection unit 103, such as an abnormality in current detection values of two or more phases, is output to an external electronic control device. In the case of F=0, since it is normal, failure information is not output to the external electronic control unit, or information indicating normality is output. An anomaly in the current detection value of each phase can be grasped by providing a notification unit (not shown) to notify based on the failure information output to the external electronic control unit.

Although the case where the amplitude of the current detection value of one phase becomes excessive has been described as an example, the same processing is used to detect an abnormality where the amplitude of the current detection value of one phase becomes too small. be able to.

According to this embodiment, it is possible to accurately detect that the current detection value of one phase is abnormal while the motor 300 is being driven. In general, in a vehicle equipped with the motor 300, it was not possible to accurately detect that the current detection value was abnormal while the motor 300 was being driven in a normal running state, but in the present embodiment, this is possible. Become.

[Second embodiment]
FIG. 6 is a circuit configuration diagram of a motor control device 100' according to the second embodiment.
A motor control device 100' according to the present embodiment differs from the motor control device 100 shown in the first embodiment in that a current correction unit 107 is provided. The same parts as those of the motor control device 100 shown in the first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

The current correction unit 107 receives the current detection values Iu_s, Iv_s, and Iw_s from the current detection unit 103 . Furthermore, current ratios Gu, Gv, and Gw are input from the current ratio calculator 105 . Then, based on the abnormality information from the current value abnormality determination unit 106 , the abnormal current detection values are corrected, and the corrected current detection values I′u_s, I′v_s, and I′w_s are output to the main control unit 102 . The current detection values are corrected by holding the current ratios Gu, Gv, and Gw for a certain period of time and calculating the average value.

Main control unit 102 corrects detected current values I′u_s, I 'v_s and I'w_s are used to control the power conversion circuit 101 . When the abnormality information is F=4, all the switching elements 121 of the power conversion circuit 101 are turned off, or all the switching elements 121 of the upper arm or the lower arm are turned on, as in the first embodiment. output a drive signal to

FIG. 7 is a flowchart showing processing of the current correction unit 107. As shown in FIG.
In step S702, the current correction unit 107 stores the input current ratios Gu, Gv, and Gw as current ratios Gu_m, Gv_m, and Gw_m. Next, in step S703, past current ratios exceeding the maximum number N of samples are discarded. Then, in the next step S704, the average value of the current ratios is obtained from the saved N current ratios of each phase. The average value G'u of the current ratio with the U phase as the reference is obtained from the following equation (10), and the average value G'v of the current ratio with the V phase as the reference is obtained from the following equation (11) with the W phase as the reference. The average value G'w of the current ratio is calculated from the following equation (12).

After the process of step S704, the process proceeds to step S705. In step S<b>705 , the current correction unit 107 determines abnormality information from the current value abnormality determination unit 106 . That is, it is determined whether the condition of F=0 is satisfied. If this condition is satisfied, that is, if the current detection value is normal, the process proceeds to step S706. In step S706, the current correction unit 107 uses the current detection values Iu_s, Iv_s, and Iw_s input from the current detection unit 103 as the current detection values I'u_s, I'v_s, and I'w_s without correcting them.

If it is determined in step S705 that the condition of F=0 is not satisfied, the process proceeds to step S707. In step S707, the current correction unit 107 determines whether F=1. If it is determined that F=1, the process proceeds to step S708.

In step S708, the current correction unit 107 multiplies the average value G′u of the current ratio with respect to the U phase by the U-phase current detection value Iu_s, and obtains the U-phase corrected current detection value I′u_s. . For the other phases, the current detection values Iv_s and Iw_s are set to the current detection values I'v_s and I'w_s without correction. If it is not determined in step S707 that F=1, the process proceeds to step S709.

In step S709, the current correction unit 107 determines whether F=2. If it is determined that F=2, the process proceeds to step S710.

In step S710, the current correction unit 107 multiplies the V-phase current detection value Iv_s by the average value G′v of the current ratio with respect to the V-phase as a corrected current detection value I′v_s of the V-phase. . For the other phases, the current detection values Iu_s and Iw_s are set to the current detection values I'u_s and I'w_s without correction. If it is not determined in step S709 that F=2, the process proceeds to step S711.

In step S711, the current correction unit 107 determines whether F=3. If it is determined that F=3, the process proceeds to step S712.

In step S712, the current correction unit 107 multiplies the W-phase current detection value Iw_s by the W-phase current detection value Iw_s by the W-phase current ratio average value G′w. do. For the other phases, the current detection values Iu_s and Iv_s are set to the current detection values I'u_s and I'vs without correction. If it is not determined in step S711 that F=3, the process proceeds to step S713.

In step S713, the current correction unit 107 corrects the current detection values Iu_s, Iv_s, and Iw_s input from the current detection unit 103 because the abnormality is F≠0≠1≠2≠3 and cannot be corrected. , are used as they are as current detection values I'u_s, I'v_s, and I'w_s.

After steps S<b>706 , S<b>708 , S<b>710 , S<b>712 , and S<b>713 , the process proceeds to step S<b>714 , and current correction unit 107 outputs current detection values I′u_s, I′v_s, and I′w_s to main control unit 102 .

According to this embodiment, it is possible to accurately detect that the current detection value of one phase is abnormal while the motor 300 is being driven, and furthermore, it is possible to correct the current detection value of one phase that is abnormal while the motor 300 is being driven. Therefore, the vehicle equipped with the motor 300 can continue to run. In this embodiment, in step S704, the average values G'u, G'v, and G'w of the current ratios based on the U-phase, V-phase, and W-phase, respectively, are obtained. is not performed, and only the values used in the respective processing among the average values G'u, G'v, and G'w are calculated in subsequent steps S708, S710, and S712. good.

[Third embodiment]
FIG. 8 is a circuit configuration diagram of a motor control device 100'' according to the third embodiment.
A motor control device 100″ in this embodiment differs from the motor control device 100′ shown in the second embodiment in the processing of the current ratio calculation unit 105. The same parts as those of the control devices 100 and 100' are denoted by the same reference numerals, and the description thereof is omitted.

In the first and second embodiments, the processing of the current ratio calculator 105 is synchronized with the sampling timing of the current detector 103 . Therefore, when the sampling timing interval is short, the number of calculations of the current ratio calculation unit 105 increases and the load is increased. Therefore, in the third embodiment, when the motor 300 is running at a low speed, the number of calculations by the current ratio calculator 105 is reduced.

Main control unit 102 calculates rotation speed Nm of motor 300 based on electrical angle θe_s input from angle calculation unit 104 . A current ratio calculation unit 105 receives the rotation speed Nm of the motor 300 from the main control unit 102, and calculates the current ratio in synchronization with the sampling timing of the current detection unit 103 if the rotation speed N'm is equal to or higher than a certain rotation speed. On the other hand, if the number of revolutions Nm of the motor 300 is lower than the constant number of revolutions N'm, the electrical angle θe_s is used to measure the time T2π that changes from 0 degrees to 360 degrees, and the number of samples S (≧2) per 180 degrees. Calculate the calculation timing Ts. The current ratio calculator 105 calculates and outputs the current ratio in synchronization with this calculation timing Ts.

FIG. 9 is a flowchart showing processing of the current ratio calculator 105 according to this embodiment. The current ratio calculator 105 executes the flowchart shown in FIG. 9 while the motor 300 is being driven.

In step S901, the current ratio calculation unit 105 determines whether the current detection values Iu_s, Iv_s, and Iw_s sampled by the current detection unit 103 have been received. If not received, the process of step S901 is repeated until it is received. If received, the process proceeds to the next step S902.

In step S<b>902 , the current ratio calculator 105 determines whether the rotation speed Nm of the motor 300 is equal to or higher than a certain rotation speed N′m. If the rotation speed is high, in step S903, the current ratio calculation unit 105 calculates the current ratios Gu, Gv , Gw respectively. Then, in step S 904 , the calculated current ratios Gu, Gv, and Gw are output to current value abnormality determination section 106 and current correction section 107 . After the processing ends, the processing shown in FIG. 7 is repeated.

If it is determined in step S902 that the rotation speed Nm of the motor 300 is lower than the constant rotation speed N'm, the process proceeds to step S905.

In step S905, the current ratio calculator 105 measures the time T2π that changes from 0 degrees to 360 degrees using the electrical angle θe_s. Then, in the next step S906, the calculation timing Ts is obtained by dividing the time T2π by 2S. S (≧2) is the number of samples per electrical angle of 180 degrees. A counter ts is initialized in the next step S907. Then, in the next step S908, the counter ts is counted up. In step S909, it is determined whether or not the counter ts exceeds the calculation timing Ts. If not, the process returns to step S908. Output to the section 106 and the current correction section 107 . The processing of the current value abnormality determination unit 106 is the same as the content described with reference to FIG.

FIG. 10 is a flowchart showing processing of the current correction unit 107 according to this embodiment.
In step S701, the current correction unit 107 determines whether the current ratios Gu, Gv, and Gw input from the current ratio calculation unit 105 have been updated from the previous input values. If it has been updated, the process proceeds to step S702. The processing after step S702 is the same as the content described with reference to FIG.

After the process of step S704, or when the current ratios Gu, Gv, and Gw have not been updated from the values at the time of the previous input in step S701, the process proceeds to step S705. If the current ratios Gu, Gv, and Gw have not been updated, the current detection values are corrected as shown in the following steps based on the average value of the current ratios calculated last time.
Since the processing after step S705 is the same as the content explained with reference to FIG. 7, the explanation thereof is omitted.

In the present embodiment, the current ratio calculator 105 obtains the calculation timing Ts according to the motor rotation speed Nm, and calculates and outputs the current ratio in synchronization with the calculation timing Ts. As another example, the sampling timings of the current detection values Iu_s, Iv_s, and Iw_s in the current detection unit 103 may be determined according to the motor rotation speed Nm. That is, the current detection unit 103 refers to the rotation speed Nm of the motor 300, and when the rotation speed Nm of the motor 300 is low, the sampling timing is sparse, and when the rotation speed Nm of the motor 300 is high, the sampling timing is dense. do. In this case, the current ratio calculator 105 performs the processing described with reference to the flowchart of FIG. That is, the current ratio calculation unit 105 executes the processing of the flowchart shown in FIG. 4 according to the motor rotation speed Nm, so that the load of the current ratio calculation unit 105 increasing the number of calculations can be reduced.

According to this embodiment, it is possible to accurately detect that the current detection value of one phase is abnormal while the motor 300 is being driven, and furthermore, it is possible to reduce the calculation load for detecting that the current detection value is abnormal. .

In each of the embodiments described above, the circuit diagrams of the motor control devices 100, 100', 100'', 100', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', 100'', and 100'' The description has been given by dividing into a plurality of blocks such as the unit 106 and the current correction unit 107. However, the division into these blocks is an example, and a program describing the functions of all or a part of the plurality of blocks is executed by a processor (for example, a CPU , GPU).

According to the embodiment described above, the following effects are obtained.
(1) The current detection device detects the current detection value of one of the three-phase alternating currents output to the three-phase motor 300 while the three-phase motor 300 is being driven. A current ratio calculation unit 105 that calculates a current ratio that is a ratio of the sum of two-phase current detection values, and if the current ratio calculated by the current ratio calculation unit 105 is within a predetermined range, and a current value abnormality determination unit 106 that determines that the detected current value is normal and determines that the detected current value of one phase is abnormal when the current ratio is not within a predetermined range. As a result, it is possible to accurately detect that the current detection value of one phase is abnormal during driving of the motor.

(2) The motor control devices 100, 100′, and 100″ include a current detector 103 that detects the three-phase alternating current that is being output to the three-phase motor 300, and a three-phase alternating current that detects the three-phase alternating current while the three-phase motor 300 is being driven. A current ratio calculation unit 105 that calculates a current ratio, which is the ratio of the sum of the current detection values of the other two phases to the current detection value of one phase, and the current ratio calculated by the current ratio calculation unit 105 is within a predetermined range , it is determined that each current detection value of the three-phase alternating current detected by the current detection unit 103 is normal, and if the current ratio is not within the predetermined range, the current detection value of one phase is abnormal. and a current value abnormality determination unit 106 that determines that there is an abnormality, whereby it is possible to accurately detect that the current detection value of one phase is abnormal during driving of the motor.

The present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention as long as the features of the present invention are not impaired. . Moreover, it is good also as a structure which combined above-mentioned each embodiment and modification.

100, 100′, 100″ motor control device 101 power conversion circuit 102 main control unit 103 current detection unit 104 angle calculation unit 105 Current ratio calculation unit 106 Current value abnormality determination unit 107 Current correction unit 200 DC power supply 300 Motor 301 Angle sensor Tuu U phase upper arm switching element, Duu... U-phase upper arm diode, Tul... U-phase lower arm switching element, Dul... U-phase lower arm diode, Tvu... V-phase upper arm switching element, Dvu... V-phase upper arm diode, Tvl... V-phase lower arm switching element, Dvl... V-phase lower arm diode, Twu... W-phase upper arm switching element, Dwu... W-phase upper arm diode, Twl. . . W-phase lower arm switching element, Dwl . . . W-phase lower arm diode.

Claims (11)

A current for calculating a current ratio, which is a ratio of the sum of the current detection value of one phase and the sum of the current detection values of the other two phases among the three-phase alternating currents output to the three-phase motor while the three-phase motor is being driven. a ratio calculation unit;
When the current ratio calculated by the current ratio calculation unit is within a predetermined range, each current detection value of the three-phase alternating current is determined to be normal, and the current ratio is not included in the predetermined range. and a current value abnormality determination unit that determines that the current detection value of the one phase is abnormal when the current detection value of the one phase is abnormal. The current detection device according to claim 1,
The current ratio calculation unit calculates the three current ratios based on each phase,
The current value abnormality determination unit determines that the reference current detection value of one phase is abnormal when any one of the three current ratios is not within the predetermined range. The current detection device according to claim 2,
An angle calculation unit that calculates an electrical angle based on angle information from the three-phase motor,
The current value abnormality determination section is a current detection device that determines whether or not the current detection value is abnormal within the constant angular range of the electrical angle calculated by the angle calculation section. In the current detection device according to claim 3,
The current detection device, wherein the constant angular range of the electrical angle is 180 degrees. In the current detection device according to claim 3 or 4,
When the current value abnormality determination unit determines that the current detection value of any one of the three-phase alternating currents is abnormal, the average value of the current ratio of the phase in the constant angle range is determined. A current detection device comprising a current correction unit that multiplies and outputs the current detection value. a current detector that detects the three-phase alternating current that is being output to the three-phase motor;
a current ratio calculation unit that calculates a current ratio, which is a ratio of the sum of the current detection value of one phase and the sum of the current detection values of the other two phases among the three-phase alternating currents, while the three-phase motor is being driven;
When the current ratio calculated by the current ratio calculation unit is within a predetermined range, each current detection value of the three-phase alternating current detected by the current detection unit is determined to be normal, and the current ratio is determined to be normal. and a current value abnormality determination unit that determines that the current detection value of the one phase is abnormal when is not included in the predetermined range. In the motor control device according to claim 6,
The current ratio calculation unit calculates the three current ratios based on each phase,
The current value abnormality determination unit determines that the one-phase current detection value used as the reference is abnormal when any one of the three current ratios is not included in the predetermined range. In the motor control device according to claim 7,
An angle calculation unit that calculates an electrical angle based on angle information from the three-phase motor,
The current value abnormality determination unit determines whether the current detection value is abnormal within the constant angular range of the electrical angle calculated by the angle calculation unit. In the motor control device according to claim 8,
The motor control device, wherein the constant angular range of the electrical angle is 180 degrees. In the motor control device according to claim 8,
When the current value abnormality determination unit determines that the current detection value of any one of the three-phase alternating currents is abnormal, the average value of the current ratio of the phase in the constant angle range is determined. A motor control device comprising a current correction unit that multiplies the current detection value and outputs the result. In the motor control device according to any one of claims 6 to 10,
A three-phase upper and lower arm series circuit composed of switching elements is provided, and the switching operation of the switching elements converts the supplied DC power into AC power and outputs the three-phase AC current to the three-phase motor. a power conversion circuit;
A main control unit that drives and controls the switching element of the power conversion circuit,
The main control unit turns off all the switching elements of the power conversion circuit, or turns off the upper arm or the lower arm when the current value abnormality determination unit determines that the current detection value is abnormal. A motor control device that outputs a drive signal to turn on all of the switching elements of.

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