JP2014212639A - Detector for drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detector for a drive unit, capable of precisely detecting a disconnection in a motor feeder line.SOLUTION: A full-bridge circuit is formed from switching elements FET1-FET4 and is connected with a motor 1 through motor feeder lines 4a, 4b. When all the switching elements FET1-FET4 are off, a power supply +V is fed to resistors R1-R4. A first detection voltage VMis detected with a division ratio of the resistor R1 to the resistor R2 and a second detection voltage VMis detected with a division ratio of the resistor R3 to the resistor R4. When an absolute value of a difference between the first detection voltage VMand the second detection voltage VMis equal to or larger than a predetermined value, the motor feeder lines 4a, 4b are determined to be disconnected.

Description

  The present invention relates to a detection device for a drive device that detects disconnection of a motor power supply line connected to a motor.

  In a bridge circuit that drives a motor, as an apparatus for monitoring disconnection of a motor power supply line when the motor is stopped, for example, Patent Document 1 shown below can be cited.

JP 2007-176207 A (Patent No. 4667234)

  In Patent Document 1, in order to detect disconnection of a motor power supply line, a first detection resistor connected in parallel to one upstream side of the bridge circuit and a second connected in parallel to the downstream side of the bridge circuit. The disconnection is detected from the magnitude relationship of the voltage at the end of the motor power supply line with the detection resistor.

  However, in Patent Document 1, since the resistance value of the first detection resistor is equal to the resistance value of the second detection resistor, when the first and second detection resistors are energized, The voltage difference is difficult to output. Therefore, even if the motor power supply line is normal, it may be erroneously determined as a disconnection.

  The present invention has been provided in view of the above-described problems, and an object of the present invention is to provide a detection device for a drive device that can accurately detect disconnection of a motor power supply line.

In the present invention, motors connected to terminals on both sides of the motor 1 by motor feed lines 4a and 4b from the midpoints of the half bridges on both sides of the full bridge circuit including the switching elements FET1 to FET4 on each bridge side, respectively. A drive circuit 2;
A first resistor R1 and a second resistor R2 each having one end connected to the one motor feed line 4a side;
A third resistor R3 and a fourth resistor R4 each having one end connected to the other motor power supply line 4b;
The other end of the first resistor R1 and the other end of the third resistor R3 are connected to a power source + V, respectively.
The other end of the second resistor R2 and the other end of the fourth resistor R4 are grounded,
When all of the switching elements FET1 to FET4 are off and the first resistor R1 and the third resistor R3 are energized from the power supply + V, the first resistor R1 and the second resistor first between the detection voltage VM ₊ generated between the R2, the second detection voltage VM generated between the third resistor R3 and the fourth resistor R4 _- comparing the said first detection voltage VM ₊ and the second detection voltage VM of _- if the absolute value of the difference is equal to or greater than a predetermined value set in advance, provided with a determination unit and the motor feed line 4a, 4b is disconnected It is characterized by having.

(1) According to the present invention, when the first resistor R1 and the third resistor R3 are energized from the power supply + V with all of the switching elements FET1 to FET4 being turned off, A first detection voltage VM ₊ generated between the resistor R1 and the second resistor R2, and a second detection voltage VM ₋ generated between the third resistor R3 and the fourth resistor R4. comparing the door, the first detection voltage VM ₊ and the second detection voltage VM _- in the case of more than the absolute value of a predetermined set in advance the value of the difference of the motor feed line 4a, 4b is in disconnection Since it is determined that there is a disconnection, the disconnection of the motor power supply lines 4a and 4b can be detected with high accuracy.

(2) According to the present invention, the determination means is configured such that the first resistor R1 and the third resistor R3 are energized from the power source + V with all of the switching elements FET1 to FET4 being off, the first detection voltage VM ₊ and the second detection voltage VM _- in the case of the second predetermined value or less the absolute value of the difference of preset, the motor feed line 4a, and 4b are normal determination By doing so, it is possible to prevent errors due to component variations and voltage / temperature changes.

(3) According to the present invention, since the power supply + V is different from the motor power supply + B supplied to the switching elements FET1 to FET4, it can be made less susceptible to noise and the like due to energization.

(4) According to the present invention, the resistance value of the first resistor R1 and the resistance value of the third resistor R3 are equal, and the resistance value of the second resistor R2 and the resistance of the fourth resistor R4 The value is set larger than the resistance values of the first and third resistors R1 and R3, and the resistance value of the fourth resistor R4 is set larger than the resistance value of the second resistor R2. The difference between the first detection voltage VM ₊ and the second detection voltage VM ₋ when the motor power supply lines 4a and 4b are disconnected can be increased, and the disconnection and normality of the motor power supply lines 4a and 4b are reliably detected with high accuracy. be able to.

(5) having a control unit 10 that controls the driving of the motor 1, and the first detection voltage VM ₊ and the second detection voltage VM ₋ are within a predetermined voltage range that can be detected by the control unit 10. is, the determining means in said voltage range, the first detection voltage VM ₊ and the second detection voltage VM _- in the case of more than the absolute value of a predetermined set in advance the value of the difference of the motor Since it is determined that the power supply lines 4a and 4b are disconnected, the disconnection of the motor power supply lines 4a and 4b can be detected with higher accuracy.

1 is a block circuit diagram according to a first embodiment of the present invention. It is explanatory drawing which shows the state through which the electric current flows when the motor in the 1st Embodiment of this invention is carrying out normal rotation drive. It is explanatory drawing which shows the state through which the electric current flows in the case of reversely driving the motor in the 1st Embodiment of this invention. It is explanatory drawing at the time of normal of the motor electric power feeding line in the 1st Embodiment of this invention. It is an equivalent circuit diagram in the normal time of the motor feed line in the first embodiment of the present invention. It is explanatory drawing at the time of the disconnection of the motor electric power feeding line in the 1st Embodiment of this invention. FIG. 3 is an equivalent circuit diagram when the motor power supply line is disconnected in the first embodiment of the present invention. It is a flowchart in the case of determining the normality of the motor feed line and the disconnection in the first embodiment of the present invention. It is a principal part circuit diagram in the 2nd Embodiment of this invention. It is explanatory drawing at the time of normal of the motor electric power feeding line in the 2nd Embodiment of this invention. It is explanatory drawing at the time of the disconnection of the motor electric power feeding line in the 2nd Embodiment of this invention. It is explanatory drawing when the power fault in the 2nd Embodiment of this invention generate | occur | produces. It is explanatory drawing when the ground fault generate | occur | produces in the 2nd Embodiment of this invention. It is explanatory drawing in the case of detecting the power fault in the 2nd Embodiment of this invention. It is explanatory drawing in the case of detecting a ground fault in the 2nd Embodiment of this invention.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block circuit diagram related to the present invention. A motor drive circuit 2 for driving a motor 1 so as to be capable of forward and reverse rotation has a well-known full bridge circuit configuration. Switching elements FET1 to FET4 are provided on each bridge side of the full bridge circuit.

The control unit 10 composed of a microcomputer controls the whole according to a predetermined program procedure. The control unit 10 controls a motor driver 12 composed of an IC. The motor driver 12 controls the switching elements FET1 to FET4 to be turned on and off, so that the motor 1 is supplied with motor power + B. Drives forward or reverse.
The storage unit 11 includes the program, a ROM that stores various preset values, a nonvolatile RAM that temporarily stores data, and the like.

In the full bridge circuit, the switching element FET1 and switching element FET2 of one half bridge are connected in series, the drain of the switching element FET1 is connected to the motor power supply + B, and the source of the switching element FET2 is grounded.
The switching element FET3 and the switching element FET4 of the other half bridge are connected in series, the drain of the switching element FET3 is connected to the motor power supply + B, and the source of the switching element FET4 is grounded.

  A connection point (middle point) between the switching element FET1 and the switching element FET2 is connected to one terminal of the motor 1 via the motor power supply line 4a. Further, the switching element FET3 and the switching element FET4 are connected to the other terminal of the motor 1 through the motor power supply line 4b from the connection point (middle point).

Here, one end of the first resistor R1 and one end of the second resistor R2 are connected to the motor power supply line 4a, and one end of the second resistor R2 and one end of the fourth resistor R4 are connected to the motor supply line 4a. It is connected to the motor power supply line 4b.
The other end of the first resistor R1 and the other end of the third resistor R3 are respectively connected to a power source + V of a different system different from the motor power source + B. The other end of the second resistor R2 and the other end of the fourth resistor R4 are grounded.

A part that detects a voltage between the first resistor R1 and the second resistor R2 is a first detection point 21, and a voltage detected as a divided voltage between the first resistor R1 and the second resistor R2. Is detected at the first detection point 21 as the first detection voltage VM ₊ .
Further, a part for detecting a voltage between the third resistor R3 and the fourth resistor R4 is set as a second detection point 22, and is detected as a divided voltage between the third resistor R3 and the fourth resistor R4. This voltage is detected at the second detection point 22 as the second detection voltage VM ₋ .

The first detection voltage VM ₊ detected at the first detection point 21 is detected by the first voltage detector 15, and the second detection voltage VM ₋ detected at the second detection point 22 is It is detected by the second voltage detector 16.
Then, the first detection voltage VM ₊ detected by the first voltage detection unit 15 and the second detection voltage VM ₋ detected by the second voltage detection unit 16 are input to the control unit 10.

The control unit 10 includes a comparing and judging section 18, at the comparison determination unit 18 first detects the voltage VM ₊ and the second detection voltage VM _- arithmetically processing the absolute value of the difference between. As a result of the arithmetic processing, as will be described later, it is determined whether the motor power supply lines 4a and 4b are disconnected or not (normal). In addition, the control part 10 provided with the comparison judgment part 18 comprises the determination means.
When the motor power supply lines 4a and 4b are disconnected, the control unit 10 drives the notification unit 13 to notify the user with a lamp, a buzzer, or the like.

  Here, the motor 1 drives the driven object by operating and releasing the electric parking brake, opening / closing the sliding door and the back door of the vehicle, opening / closing the window, driving the seat, opening / closing the sunroof, etc. Used as a drive unit or drive source.

FIG. 2 shows a case where the control unit 10 turns on the switching element FET1 and the switching element FET4 and turns off the switching element FET2 and the switching element FET3 to drive the motor 1 in, for example, normal rotation. The arrows in the figure indicate the current flowing through the switching element FET1 and the motor 1.
FIG. 3 shows a case where the motor 1 is driven in reverse to the case of FIG. 2. In this case, the control unit 10 turns on the switching element FET3 and the switching element FET3, and the switching element FET1 and the switching element FET4. Turn off. The arrows in the figure indicate the current flowing through the switching element FET3 and the motor 1.

Next, the determination of whether the motor power supply lines 4a and 4b are disconnected or normal will be described. As a method of determining whether or not the motor power supply lines 4a and 4b are disconnected, a method of determining whether or not the switch is disconnected by turning on a switch element (for example, FET 4) and passing a drive current to the motor 1 is also conceivable. When the switch element is turned on, noise is generated, which may affect other devices. By determining using the first resistor R1 to the fourth resistor R4 in order to determine the disconnection of the motor power supply lines 4a and 4b, it is possible to reduce the occurrence of noise due to the ON operation of the switch element.
FIG. 4 shows a normal case where the motor power supply lines 4a and 4b are not disconnected, and only a circuit diagram of the main part is shown.
The resistance value of the first resistor R1 is 12.1 kΩ, the resistance value of the second resistor R2 is 18.9 kΩ, and the resistance value of the third resistor R3 is the same as the resistance value of the first resistor R1. 12.1 kΩ. The resistance value of the fourth resistor R4 is 41.2 kΩ.

A control operation for determining whether or not the motor power supply lines 4a and 4b are disconnected will be described with reference to FIGS. 4 and 5 and FIG. 8 showing a flowchart. First, as shown in step S1 of FIG. 8, the control unit 10 determines whether power supply to the motor 1 is stopped, that is, whether all of the switching elements FET1 to FET4 are turned off.
When all of the switching elements FET1 to FET4 are turned off, the control unit 10 supplies 24V to the power supply + V and energizes the resistors R1 to R4 as shown in FIG. In a normal case where the motor power supply lines 4a and 4b are not disconnected, the first detection point 21 and the second detection point 22 are in a conductive state via the motor power supply line 4a, the motor 1 and the motor power supply line 4b. Yes.

  Therefore, as shown in FIG. 5, the first resistor R1 and the third resistor R3 are connected in parallel, and the second resistor R2 and the fourth resistor R4 are also connected in parallel. It becomes. The combined resistance value in parallel of the first resistor R1 and the third resistor R3 is about 6 kΩ, and the combined resistance value in parallel of the second resistor R2 and the fourth resistor R4 is about 13 kΩ.

When 24V of the power source + V is supplied to the circuit shown in FIG. 5, about 16.4V is generated as the first detection voltage VM ₊ at the first detection point 21 from the voltage dividing ratio of 6 kΩ and 13 kΩ, and the second At the detection point 22, about 16.4 V is generated as the second detection voltage VM ₋ .
The first detection voltage VM ₊ and the second detection voltage VM ₋ are detected by the first voltage detection unit 15 and the second voltage detection unit 16 (see step S2 in FIG. 8).

Next, as shown in step S _< b _{> 3} , the control unit 10 performs calculation processing of the absolute value of the difference between 16.4 V of the first detection voltage VM ₊ and 16.4 V of the second detection voltage VM ₋ . In other words, | VM ₊ −VM ₋ | = | 16.4V−16.4V | = 0V, and this absolute value of 0V is compared with a preset predetermined value of 60 mV (second predetermined value). Perform (see step S4). This 60 mV is stored in advance in the storage unit 11, and the comparison / determination unit 18 of the control unit 10 compares the 60 mV with the calculated absolute value.

In this example, 0V ≦ 60 mV, and the absolute value of the difference between the first detection voltage VM ₊ and the second detection voltage VM ₋ is equal to or less than a preset value of 60 mV. 4b is determined to be normal since no disconnection has occurred (see step S5).

In the normal case where the motor feed line 4a, 4b is not broken, the first detection voltage VM ₊ and the second detection voltage VM _- is the computed difference in (theoretically), becomes to 0V, and the control In order to accurately determine the normal state and the disconnection in consideration of the variation in reading of the unit 10, the variation in resistance itself, and the temperature change, it is set to 60 mV.
Of course, this set value is not limited to 60 mV, and may be 100 mV, for example. However, as will be described later, a very high value is not used because of the relationship between the absolute value of the difference between the first detection voltage VM ₊ and the second detection voltage VM ₋ at the time of disconnection. That is, it is a numerical value that can clearly determine the normal time and the disconnection time.

Next, the case of disconnection will be described. FIG. 6 shows, for example, a case where the motor power supply line 4a is disconnected. In such a case, the first detection point 21 and the second detection point 22 are non-conductive, and the equivalent circuit is shown in FIG. As shown.
That is, as shown in FIG. 7, at the first detection point 21, the voltage of the voltage division ratio between the first resistor R1 and the second resistor R2 is detected as the first detection voltage VM ₊ . At the detection point 22, the voltage of the voltage division ratio between the third resistor R3 and the fourth resistor R4 is detected as the second detection voltage VM ₋ .

At the first detection point 21, about 14.6 V is generated as the first detection voltage VM ₊ , and at the second detection point 22, about 18.6 V is generated as the second detection voltage VM ₋ . The first detection voltage VM ₊ (14.6 V) and the second detection voltage VM ₋ (18.6 V) are detected by the first voltage detection unit 15 and the second voltage detection unit 16, and the first detection voltage VM ₊ (18.6 V) is detected. detection voltage VM ₊ and the second detection voltage VM _- absolute value of the difference is calculated (see steps S2, S3 in FIG. 8).

In step S3, | 14.6V-18.6V | is calculated, and | 2V | is calculated as an absolute value. In step S4, 2V and 60 mV are compared, and are larger than a preset value (60 mV). The process proceeds to step S6.
In step S6, since the comparison / determination unit 18 has an absolute value of 2V larger than the preset 100 mV, the process proceeds to step S8 and determines that the wire is disconnected. The preset 100 mV is stored in the storage unit 11, and the comparison / determination unit 18 reads this 100 mV and compares it with the absolute value.

The process proceeds from step S8 to step S9, and the control unit 10 drives the notification unit 13 to turn on or blink the lamp, or to notify by a buzzer sound or sound.
In the above description, the case where one of the motor power supply lines 4a is disconnected is described. However, even in the case of the other motor power supply line 4b, the disconnection can be similarly detected.

Here, the setting value in step S6 is set to 100 mV. When the motor power supply lines 4a and 4b are disconnected, the resistance values of the resistors R2 and R3 are larger than the resistance value of the resistor R1 = R3 shown in FIG. Thus, the difference between the first detection voltage VM ₊ and the second detection voltage VM ₋ is increased so that the absolute value thereof is clearly greater than 100 mV so that the disconnection can be reliably detected. Yes.
In step S6, if the absolute value of the result of the arithmetic processing is 80 mV, for example, if it is lower than 100 mV due to a reading error of the control unit 10, variations in the resistors R1 to R4, temperature change, etc., the motor power supply line 4a, It is determined that 4b is not disconnected (see step S7). And it transfers to step S1 again and is repeated from step S1 to step S7 until it is judged that it is a disconnection.

As described above, the predetermined value determined to be normal is 60 mV in the present embodiment, the predetermined value determined to be disconnection is 100 mV, and determination is performed using two predetermined values. If the value for determining whether the disconnection is normal is an adjacent value, it is difficult to determine and there is a possibility of erroneous determination. Therefore, a difference is provided between the values for determining whether the disconnection is normal or disconnection.
In order to increase the absolute value of the difference between the first detection voltage VM ₊ and the second detection voltage VM ₋ at the time of disconnection, each absolute value is surely greater than the value for determining the disconnection time. The resistance values of the resistors R1 to R4 are set.

As described above, in this embodiment, the first detection voltage VM ₊ and the second detection voltage VM _- compared with the absolute value and the preset predetermined value difference (100 mV), a first detection voltage VM ₊ second detection voltage VM _- in the case of more than the absolute value given to a preset value of the difference, in the circuit absolute value occurs at break, the motor feed line 4a, since 4b is so as to determine the disconnection The disconnection of the motor power supply lines 4a and 4b can be detected with high accuracy.

Further, when the motor feed line 4a, 4b is determined to be normal, the first detection voltage VM ₊ and the second detection voltage VM _- the value to be compared with the absolute value of the difference between the 0V without predetermined By setting the value to 60 mV, for example, errors due to component variations and voltage / temperature changes can be prevented.

  In addition to the motor power supply + B of the switching elements FET1 to 4 for driving the motor 1, a power supply + V for performing a disconnection diagnosis is provided, and this power supply + V is energized to the diagnostic circuit, that is, the power supply only when necessary. Since + V is used, it is less susceptible to noise and the like due to energization.

Also, the resistance value of the first resistor R1 and the resistance value of the third resistor R3 are made equal, and the resistance value of the second resistor R2 and the resistance value of the fourth resistor R4 are the first and third resistance values, respectively. Since the resistance value of the resistors R1 and R3 is set larger than the resistance value of the second resistor R2, and the resistance value of the fourth resistor R4 is set larger than the resistance value of the second resistor R2, the first when the motor power supply lines 4a and 4b are disconnected. detection voltage VM ₊ and the second detection voltage VM of _- and can be increased a difference between the motor feed line 4a, 4b disconnection of, can be detected reliably and accurately normal.

(Second Embodiment)
FIG. 9 is a circuit diagram of a main part of the second embodiment. A series circuit of a resistor R5 and a resistor R6 is connected in parallel with the switching element FET2, and a resistor R7 and a resistor R8 are connected in parallel with the switching element FET4. A series circuit is connected.
The first detection voltage VM ₊ is detected using the connection point between the resistors R5 and R6 as the first detection point 21, and the connection point between the resistors R7 and R8 is used as the second detection point 22. The detection voltage VM ₋ is detected.

Here, as shown in FIG. 10, the resistance value of the resistor R5 and the resistance value of the resistor R7 are each 100 kΩ, and the resistance value of the resistor R6 and the resistance value of the resistor R8 are respectively 8.2 kΩ. The resistance values of the resistors R1 to R4 are the same as in the previous embodiment, and the voltage value of the power source + V is the same as in the previous embodiment.
FIG. 10 shows a normal case where the motor power supply lines 4a and 4b are not disconnected. As in the previous embodiment, the first detection voltage VM ₊ detects about 1.24V, and the second detection voltage VM. _- But about 1.24V is detected.

Since the absolute value of the difference between the first detection voltage VM ₊ and the second detection voltage VM ₋ is 0 V, which is lower than the predetermined value of 60 mV, it is determined to be normal as shown in FIG.

FIG. 11 shows a case where the motor power supply line 4 a is disconnected. 1.11 V is detected as the first detection voltage VM ₊ at the first detection point 21, and the first detection voltage VM _{+ at} the second detection point 22 is detected. As a detection voltage VM ₋ of 2, 1.41 V is detected.
The absolute value of the difference between the first detection voltage VM ₊ and the second detection voltage VM ₋ is | 1.11V−1.41V | = 0.3 V, which is larger than a predetermined value of 100 mV, and is determined to be a disconnection.

  As described above, the present embodiment has the same effect as the previous embodiment.

FIG. 12 shows a “sky fault” state in which the motor power supply line 4a and the motor power supply + B are short-circuited (solid line A in the drawing), and is a case where the switching element FET1 or the switching element FET3 has failed to maintain the on state.
FIG. 13 shows a “ground fault” state in which the motor power supply line 4a and the ground side are short-circuited (solid line B in the figure), and is a case where the switching element FET3 or the switching element FET4 has failed to maintain the ON state. .

FIG. 14 shows an equivalent circuit in the case where a power fault (short circuit) occurs, and the first detection voltage VM ₊ detected at the first detection point 21 and the second detection point detected at the second detection point 22. detection voltage VM _- and the voltage of each power source + B is so divided voltage of 100kΩ and 8.2Keiomega, the same voltage is detected. When the divided voltage at the resistor R5 or the resistor R7 and the resistor R6 and the resistor R8 are the same, it can be detected that a power fault has occurred.

FIG. 15 shows an equivalent circuit when a ground fault (short) occurs. Since the motor power supply line 4a side is at the ground potential (GND), the first detection voltage VM ₊ detected at the first detection point 21 is The second detection voltage VM ₋ detected at the second detection point 22 is also 0V.
Therefore, when the potentials of the first detection voltage VM ₊ and the second detection voltage VM ₋ are both 0 V, it can be detected that a ground fault has occurred.
In this embodiment, when a power fault or a ground fault occurs, the first detection voltage and the second detection voltage have substantially the same value, and the first detection voltage and the second detection voltage are The difference is almost zero. Therefore, in order to judge disconnection, normality, power fault, and ground fault, if the voltage detected at the first detection voltage and the second detection voltage is different from the disconnection or normal value, the voltage is divided. Instead of making a determination based on the difference in values, it may be determined whether there is a power fault or a ground fault based on the detected voltage.

In each of the above embodiments, the first detection voltage VM ₊ and the second detection voltage VM _- voltage detected by the first resistor R1 so as to readable voltage control unit 10 side first The voltage dividing ratios of the second resistor R2, the third resistor R3, and the fourth resistor R4 are set. The resistance values of the resistors R1 to R8 are examples, and can be arbitrarily set.
For example, the control unit 10 composed of a microcomputer, so readable voltage, for example 5V, the first detection voltage VM ₊ and the second detection voltage VM _- so the voltage detected is less than 5V at the resistors R1 The resistance value of ~ R8 is set. Therefore, a predetermined value that is set in advance to determine whether the motor power supply lines 4a and 4b are disconnected is set within a range of less than 5V that is a voltage that can be read by the control unit 10. That is, the predetermined value set in advance is set within a voltage range detectable by the circuit.

1 motor 2 motor drive circuit 4a, 4b motor feeding line 10 the control unit 18 comparing and judging section R1 first resistor R2 second resistor R3 third resistor R4 fourth resistor VM ₊ first detection voltage VM _- second Detection voltage

Claims (5)

From the midpoints of the half bridges on both sides of the full bridge circuit including switching elements (FET1 to FET4) on each bridge side, the motor power lines (4a) and (4b) are respectively connected to the terminals on both sides of the motor (1). A motor drive circuit (2),
A first resistor (R1) and a second resistor (R2) each having one end connected to the one motor feed line (4a) side;
A third resistor (R3) and a fourth resistor (R4) each having one end connected to the other motor feed line (4b) side;
The other end of the first resistor (R1) and the other end of the third resistor (R3) are connected to a power source (+ V), respectively.
The other end of the second resistor (R2) and the other end of the fourth resistor (R4) are grounded,
When the first resistor (R1) and the third resistor (R3) are energized from the power supply (+ V) with all of the switching elements (FET1 to FET4) turned off, Between the first detection voltage (VM ₊ ) generated between the resistor (R1) and the second resistor (R2), and between the third resistor (R3) and the fourth resistor (R4) Is compared with a second detection voltage (VM ₋ ) generated at a predetermined absolute value of a difference between the first detection voltage (VM ₊ ) and the second detection voltage (VM ₋ ). A detection device for a drive device, comprising: a determination unit that determines that the motor power supply lines (4a) and (4b) are disconnected when the value is equal to or greater than the value. The determination means includes
The first detection voltage is supplied to the first resistor (R1) and the third resistor (R3) from the power supply (+ V) when all the switching elements (FET1 to FET4) are off. When the absolute value of the difference between (VM ₊ ) and the second detection voltage (VM ₋ ) is equal to or smaller than a predetermined second predetermined value, the motor power supply lines (4a) and (4b) are normal. The drive device detection device according to claim 1, wherein the drive device detection device is determined.   The drive device detection device according to claim 1, wherein the power supply (+ V) is different from a motor power supply (+ B) supplied to the switching elements (FET1 to FET4). The resistance value of the first resistor (R1) is equal to the resistance value of the third resistor (R3),
The resistance value of the second resistor (R2) and the resistance value of the fourth resistor (R4) are set larger than the resistance values of the first and third resistors (R1) and (R3),
The drive device according to any one of claims 1 to 3, wherein a resistance value of the fourth resistor (R4) is set larger than a resistance value of the second resistor (R2). Detection device. A controller (10) for controlling the drive of the motor (1);
The first detection voltage (VM ₊ ) and the second detection voltage (VM ₋ ) are within a predetermined voltage range that can be detected by the control unit (10).
In the voltage range, the determination means, when the absolute value of the difference between the first detection voltage (VM ₊ ) and the second detection voltage (VM ₋ ) is equal to or greater than a predetermined value, The drive device detection device according to any one of claims 1 to 4, wherein the motor power supply line (4a) (4b) is determined to be disconnected.

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