JP5808780B2 - Abnormality detection device for circuit system of stepping motor - Google Patents

Description

  The present invention relates to an apparatus for detecting the presence or absence of an abnormality in a circuit system that energizes a coil of a stepping motor.

  Conventionally, as this type of apparatus, for example, the one found in Patent Document 1 is known. In Patent Document 1, during the rotation operation of the stepping motor, during the excitation period of each phase coil, a resistance generation voltage (according to the coil energization current) provided in the motor energization circuit for supplying current from the DC power source to the coil is supplied. A technique for detecting the presence or absence of a broken wire or a short-circuit abnormality based on the generated voltage) is described.

JP-A-4-261396

  By the way, a motor energization circuit for supplying a current to a coil of each phase of a stepping motor is usually configured to be small by an IC circuit or the like. For this reason, the connection terminal at one end of the coil of one phase and the connection terminal at one end of the coil of the other phase are often adjacent to each other.

  In this case, the connection terminals are likely to be short-circuited due to poor soldering or dust adhesion. When such an abnormality occurs, the stepping motor malfunctions.

  For this reason, it is desirable that the occurrence of the abnormality can be detected even when an abnormality occurs in which the ends of the coils of the two phases are short-circuited.

  Here, in what is seen in Patent Document 1, when an abnormality occurs in which the ends of two phase coils are short-circuited, a state in which both of the two phase coils are excited (in detail) In a state where both of the two phase coils are excited so that one end of one phase coil is a positive electrode and the other phase coil short-circuited to the one end is a negative electrode) A large current will flow. For this reason, it is considered possible to detect the occurrence of the abnormality.

  On the other hand, it is desirable that the presence or absence of an abnormality in the circuit system of the stepping motor can be detected while the stepping motor is stopped, such as before the actual operation of the stepping motor is started.

  In this case, in order to detect the presence or absence of an abnormality in which the ends of the two phase coils are short-circuited, it is conceivable that an exciting current flows through both of the two phase coils.

  However, in the state where the excitation current is supplied to both of the two phase coils, the excitation magnetic flux acts on the rotor of the stepping motor from two directions. And the intensity | strength of those excitation magnetic flux tends to produce variation resulting from the variation of the resistance value of the coil of each phase, etc. As a result, in the state where the excitation current is supplied to both of the two phase coils, variations in the rotational position of the rotor are likely to occur.

  For this reason, when the operation of a stepping motor that has been confirmed to be normal is detected after detecting the presence or absence of an abnormality such that the ends of the coils of the two phases are short-circuited, adjustment control of the rotational position of the rotor is performed. An error in the rotational position of the rotor that is necessary or recognized by the control device of the stepping motor is likely to occur.

  The present invention has been made in view of such a background, and without causing an excitation current to flow through both of the two phase coils of the stepping motor, the short-circuit abnormality between the ends of the two phase coils is prevented. An object of the present invention is to provide an abnormality detection device that can detect the presence or absence.

In order to achieve this object, an abnormality detection device for a stepping motor circuit system according to the present invention energizes a stepping motor having two-phase coils of a first phase and a second phase and a coil of each phase from a DC power supply. An abnormality detection device for detecting the presence or absence of an abnormality in a circuit system comprising a motor energization circuit connected to each phase coil as much as possible,
The motor energization circuit corresponding to each coil of each phase has a positive connection state in which one end of the coil to which the motor energization circuit is connected is connected to the positive electrode of the DC power supply and a negative connection that is connected to the negative electrode of the DC power supply. A first switch circuit portion configured to be controllable to any one of a state and a cut-off state that is cut off from the positive electrode and the negative electrode of the DC power supply, and a positive electrode that connects the other end of the coil to the positive electrode of the DC power supply A second switch circuit unit configured to be controllable to any one of a connection state, a negative electrode connection state to be connected to the negative electrode of the DC power source, and a cutoff state to be disconnected from the positive electrode and the negative electrode of the DC power source. ,
Current detection means for generating an output corresponding to the current flowing from the DC power supply when energizing the coils of each phase;
An abnormality detection processing means for executing processing for detecting the presence or absence of abnormality of the circuit system based on the output of the current detection means while controlling the motor energization circuit;
When the operation of the stepping motor is stopped, the abnormality detection processing means is configured such that one of the first switch circuit portion and the second switch circuit portion of the motor energization circuit connected to the first phase coil is in a positive connection state and the other is Controlling to a negative electrode connection state, and controlling both the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the second phase coil to a positive electrode connection state or a negative electrode connection state; The first abnormality detection process for detecting the presence or absence of abnormality of the circuit system based on the output of the current detection means is executed (first invention).

  According to the first invention, the abnormality detection processing means executes the first abnormality detection process when the stepping motor is stopped.

  In the first abnormality detection process, one of the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the first phase coil is controlled to be in a positive connection state and the other is controlled in a negative connection state. And controlling both the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the second phase coil to a positive connection state or a negative connection state.

  Here, at the normal time when no abnormality such as a short circuit or disconnection has occurred, one of the both ends of the first phase coil is connected to the positive electrode of the DC power source by executing the first abnormality detection process, and The other of both ends of the first phase coil is connected to the negative electrode of the DC power supply.

  For this reason, an exciting current is passed from the DC power supply to the first phase coil.

  In addition, the second phase coil is in a state where both ends thereof are connected to the positive electrode of the DC power source or connected to the negative electrode of the DC power source (the both ends are short-circuited). Excitation current does not flow from the DC power source to the two-phase coil.

  Therefore, at the normal time, the excitation current is supplied from the DC power source only to the first phase coil by executing the first abnormality detection process.

  On the other hand, in the first abnormality detection process, when both the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the second phase coil are controlled to be in the positive connection state, the second phase A situation is assumed in which an abnormality occurs in which one end or the other end of the coil and the end connected to the negative electrode of the DC power source among both ends of the first phase coil are short-circuited.

  In this case, a relatively large short-circuit current (short-circuit current that bypasses the first-phase coil) flows from the DC power source between the end of the first-phase coil and one end or the other end of the second-phase coil. It will be.

  Therefore, the current detected by the current detection means is larger than that in the normal state. For this reason, based on the output of the current detection means, one end or the other end of the second phase coil and the end of the first phase coil (the end connected to the negative electrode of the DC power source) The occurrence of a short-circuit abnormality can be detected.

  In the first abnormality detection process, when both the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the second phase coil are controlled to be in the negative electrode connection state, the second phase Suppose that there is an abnormality in which one end or the other end of the coil and the end connected to the positive electrode of the DC power source out of both ends of the first phase coil are short-circuited.

  In this case, a relatively large short-circuit current (short-circuit current that bypasses the first-phase coil) flows from the DC power source between the end of the first-phase coil and one end or the other end of the second-phase coil. It will be.

  Therefore, the current detected by the current detection means is larger than that in the normal state. Therefore, it is possible to detect the occurrence of an abnormality in which one end or the other end of the second-phase coil and the above-described end portion (the end portion connected to the positive electrode of the DC power supply) of the first-phase coil are short-circuited.

  Therefore, according to the first aspect of the present invention, it is possible to detect the presence or absence of a short circuit abnormality between one end of the two-phase coils without applying an exciting current to both of the two-phase coils of the stepping motor. it can.

  In the first invention, the motor energization circuit connected to the first phase coil and the motor energization circuit connected to the second phase coil are one side of both ends of the first phase coil. When the first phase side connection terminal that connects the ends of the second phase coil and the second phase side connection terminal that connects one end of the second phase coils are adjacent to each other. In the first abnormality detection process, one of the first switch circuit portion and the second switch circuit portion of the motor energization circuit connected to the first phase coil is controlled to be in a positive connection state and the other is in a negative connection state. And controlling both the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the second phase coil to a positive connection state or a negative connection state by the control. Connected to the first phase side connection terminal One of the end of the first phase coil and the end of the second phase coil connected to the second phase side connection terminal is connected to the positive electrode of the DC power supply, and the other is the DC It is preferable to include at least processing for detecting the presence or absence of abnormality in the circuit system based on the output of the current detection means while executing the connection to the negative electrode of the power supply (second invention).

  That is, when a motor energization circuit of each phase is provided so that the first phase side connection terminal and the second phase side connection terminal are adjacent to each other, due to poor soldering, adhesion of dust, etc. Short circuit between connection terminals is likely to occur. Therefore, in detecting the occurrence of an abnormality in which the ends of the first-phase coil and the second-phase coil are short-circuited, particularly, the end of the first-phase coil connected to the first-phase side connection terminal. It is desirable to be able to reliably detect an abnormality in which the end of the second phase coil connected to the second phase side connection terminal is short-circuited.

  In this case, in the first abnormality detection process in the second invention, the control of the first switch circuit unit and the second switch circuit unit of the motor energization circuit of each phase for detecting the abnormality is as described above. One of an end of the first phase coil connected to the side connection terminal and an end of the second phase coil connected to the second phase side connection terminal is connected to the positive electrode of the DC power supply And the other is connected to the negative electrode of the DC power source.

  Therefore, when an abnormality occurs in which the end of the first phase coil connected to the first phase side connection terminal and the end of the second phase coil connected to the second phase side connection terminal are short-circuited. Therefore, the occurrence of the abnormality can be properly detected. Therefore, it is possible to detect with high certainty an abnormality caused by a short circuit that easily occurs among the short circuits between the ends of the first-phase and second-phase coils.

  Supplementally, among the set of the end portion of the first phase coil and the end portion of the second phase coil, for the set in which the connection terminals connecting the end portions are not adjacent to each other, the end portions of the set In general, it is difficult to cause a short circuit. As described above, among the sets of the end portions of the first-phase coil and the second-phase coil, the first set for detecting a short circuit between the end portions of the set for a set that is difficult to cause a short circuit. The abnormality detection process may be omitted.

  In the first invention or the second invention, the abnormality detection processing means, when the magnitude of the current indicated by the output of the current detection means in the first abnormality detection processing is larger than a predetermined first threshold, It is preferable that the circuit system is determined to have an abnormality (third invention).

  That is, when a short circuit occurs between the ends of the first-phase and second-phase coils, the current detected by the current detection means in the first abnormality detection process is larger than that during normal operation. . Therefore, when the magnitude of the current indicated by the output of the current detection means in the first abnormality detection process is larger than a predetermined first threshold, it is determined that there is an abnormality in the circuit system, thereby When an abnormality occurs in which the ends of the second phase coils are short-circuited, the occurrence of the abnormality can be appropriately detected.

  In the first to third inventions, the abnormality detection processing means is a first switch circuit of a motor energization circuit connected to the coil of one of the first phase and the second phase when the stepping motor is stopped. The first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the coil of the other phase. A second abnormality detection process for detecting whether or not there is an abnormality in the circuit system based on the output of the current detection means, while performing both control to the cutoff state. Is preferred (fourth invention).

  According to this fourth invention, the abnormality detection processing means further executes the second abnormality detection processing when the stepping motor is stopped.

  In the second abnormality detection process, one of the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the coil of one phase of the first phase and the second phase is in a positive connection state, and the other is Control of the negative electrode connection state and control of both the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the coil of the other phase are performed.

  As a result, at the time of normality in which no abnormality such as a short circuit has occurred, only the coil of one of the first phase and the second phase is set as a coil to be energized by executing the second abnormality detection process, Only the coil to be energized is energized by a DC power source.

  On the other hand, when there is an abnormality such as a disconnection of the coil to be energized (or a disconnection of the energization path between the coil to be energized and the DC power supply) or a short circuit between both ends of the coil to be energized In this case, no excitation current flows through the coil to be energized, or a short-circuit current that bypasses the coil to be energized flows from the DC power source.

  For this reason, the current detected by the current detection means becomes zero or becomes larger than normal. Accordingly, based on the output of the current detection means in the second abnormality detection process, the disconnection of the coil to be energized (or the disconnection of the energization path between the coil to be energized and the DC power supply), or the coil of the coil to be energized The occurrence of an abnormality such as a short circuit between both ends can be detected.

  Therefore, according to the fourth aspect of the invention, in addition to the abnormality in which the ends of the first-phase and second-phase coils are short-circuited, an abnormality in which each coil is short-circuited or disconnected can be detected.

  In the fourth aspect of the invention, the abnormality detection processing means is configured such that the magnitude of the current indicated by the output of the current detection means in the second abnormality detection processing is greater than a predetermined second threshold value, or more than the second threshold value. It is preferable that the circuit system is determined to have an abnormality when it is smaller than a predetermined third threshold value (a fifth invention).

  That is, when the disconnection of the coil to be energized in the second abnormality detection process (or the disconnection of the energization path between the coil to be energized and the DC power supply) occurs, the current detected by the current detection unit is zero. It becomes. Further, when a short circuit occurs between both ends of the energization target coil, the current detected by the current detection means is larger than that during normal operation.

  Therefore, when the magnitude of the current indicated by the output of the current detection means in the second abnormality detection process is larger than a predetermined second threshold, or smaller than a predetermined third threshold smaller than the second threshold. In addition, when it is determined that there is an abnormality in the circuit system, a disconnection of a coil to be energized (or a disconnection of an energization path between the coil to be energized and a DC power supply) occurs, or When a short circuit occurs between both ends of the coil, it is possible to appropriately detect the occurrence of those abnormalities.

  When the fifth invention is applied to the third invention, the second threshold value may be the same value as the first threshold value.

The figure which shows the circuit structure of the control system of the stepping motor in one Embodiment of this invention. The figure which shows the relationship between the command signal for control of a motor energization circuit, and an output. (A), (b) is a timing chart which shows the method of energization control of the coil at the time of operation of a stepping motor. (A)-(d) is a timing chart for demonstrating abnormality detection processing.

  An embodiment of the present invention will be described below with reference to FIGS.

  FIG. 1 shows a configuration of a circuit system for performing drive control of the stepping motor 1. This circuit system includes a function as an embodiment of the abnormality detection device of the present invention.

  In the present embodiment, the stepping motor 1 is a bipolar stepping motor in which two-phase coils 2A and 2B of a phase A coil 2A and a phase B coil 2B are mounted on a stator (not shown).

  The stepping motor 1 is used as an actuator (power source) for a water amount control valve of a water heater or a gas amount adjustment valve of a gas stove, for example. However, the stepping motor 1 may be used as an actuator for equipment other than the water heater and the gas stove.

  The A-phase coil 2A and the B-phase coil 2B correspond to the first-phase coil and the second-phase coil in the present invention, respectively. However, the B phase coil 2B may be regarded as a first phase coil and the A phase coil 2A may be regarded as a second phase coil.

  The circuit system shown in FIG. 1 controls a DC power supply 10 as a power source for the stepping motor 1, a motor drive circuit 20 that supplies power to the stepping motor 1 from the DC power supply 10, and the operation of the stepping motor 1 through the motor drive circuit 20. Control unit 30.

  The DC power supply 10 is constituted by a battery, for example. In this embodiment, the negative electrode of the DC power supply 10 is grounded as a ground electrode. Note that the DC power supply 10 may be configured by a power converter that converts AC power, such as commercial power, into DC power and outputs the DC power.

  The motor drive circuit 20 is an integrated circuit in this embodiment. The motor drive circuit 20 includes an A-phase side motor energizing circuit 21A for energizing the A-phase coil 2A of the stepping motor 1 from the DC power source 10, and a B-phase side for energizing the B-phase coil 2B from the DC power source 10. Motor energization circuit 21B, and a switching control unit 24 for performing on / off control of a semiconductor switch element described later provided in these motor energization circuits 21A and 21B.

  The motor drive circuit 20 has a power supply terminal Vcc, a ground terminal GND, command signal input terminals IN1, IN2, IN3, and IN4 and output terminals OUT1, OUT2, OUT3, and OUT4 as connection terminals.

  The ground terminal GND is grounded to the same potential as the negative electrode of the DC power supply 10 outside the motor drive circuit 20.

  The power supply terminal Vcc is a connection terminal (power supply voltage input terminal) to which power supply power is supplied to and from the ground terminal GND, and is connected to the positive electrode of the DC power supply 10 outside the motor drive circuit 20. In this case, in the present embodiment, the power supply terminal Vcc is connected to the positive electrode of the DC power supply 10 via the current detection resistor 12 for detecting the current supplied from the DC power supply 10 to the stepping motor 1. The current detecting resistor 12 corresponds to the current detecting means in the present invention.

  A capacitor 11 for smoothing the power supply voltage applied to the power supply terminal Vcc is connected between the power supply terminal Vcc and the negative electrode (grounding electrode) of the DC power supply 10 (or between the grounding terminal GND). ing.

  Out of the output terminals OUT1, OUT2, OUT3, and OUT4, OUT1 and OUT2 are connection terminals for connecting the A-phase coil 2A to the A-phase side motor energization circuit 21A. These output terminals OUT1 and OUT2 are respectively connected to one end and the other end of the A-phase coil 2A outside the motor drive circuit 20 via appropriate connection cables (conduction wires).

  The output terminals OUT3 and OUT4 are connection terminals for connecting the B phase coil 2B to the B phase motor energization circuit 21B. These output terminals OUT3 and OUT4 are respectively connected to one end and the other end of the B-phase coil 2B outside the motor drive circuit 20 through appropriate connection cables (conduction wires).

  These output terminals OUT1, OUT2, OUT3, and OUT4 are arranged on one side surface of the motor driving circuit 20 so as to be adjacent to each other and arranged in order. The output terminals OUT2 and OUT3 correspond to the first phase side connection terminal and the second phase side connection terminal in the present invention, respectively.

  When the A-phase coil 2A is regarded as a second-phase coil and the B-phase coil 2B is regarded as a first-phase coil, the output terminals OUT2 and OUT3 are respectively the second-phase side connection terminal and the first-phase connection terminal in the present invention. Corresponds to the phase side connection terminal.

  Of the command signal input terminals IN1, IN2, IN3, and IN4, IN1 and IN2 are connection terminals for inputting a command signal for controlling the A-phase side motor energization circuit 21A to the switching control unit 24, and IN3 and IN4 are This is a connection terminal for inputting a command signal for controlling the B-phase side motor energization circuit 21 </ b> B to the switching control unit 24.

  These command signal input terminals IN1, IN2, IN3, and IN4 are connected to the control unit 30 via an appropriate connection cable (or via a circuit board wiring pattern) outside the motor drive circuit 20. .

  In this case, the command signal input from the control unit 30 to the command signal input terminals IN1, IN2, IN3, and IN4 is a signal of a binary level of high (H) or low (L). Hereinafter, the high level command signal is referred to as an H level command signal, and the low level command signal is referred to as an L level command signal.

  Then, according to the combination of the command signals applied to the command signal input terminals IN1 and IN2, the operating state of the A-phase side motor energization circuit 21A (as a result, from the A-phase side motor energization circuit 21A to the output terminals OUT1 and OUT2). The applied potential level) is defined.

  Similarly, depending on the combination of command signals applied to the command signal input terminals IN3 and IN4, the operating state of the B-phase side motor energization circuit 21B (as a result, the output terminals OUT3 and OUT4 from the B-phase side motor energization circuit 21B). Potential level) is defined.

  The motor energization circuits 21A and 21B for each phase are circuits having the same configuration. Specifically, the motor energization circuits 21A and 21B for each phase are so-called H-bridge type switching circuits.

  More specifically, the motor energization circuits 21A and 21B for each phase are constituted by a first switch circuit unit 22 including semiconductor switch elements S1 and S2 and a second switch circuit unit 23 including semiconductor switch elements S3 and S4. ing. The semiconductor switch elements S1 to S4 are composed of, for example, transistors (bipolar transistors in the illustrated example), and can be turned on and off. The semiconductor switch elements S1 to S4 may be configured by, for example, an FET (field effect transistor) or an IGBT (insulated gate bipolar transistor).

  The first switch circuit section 22 includes a switch section formed by connecting a diode D1 in parallel to the semiconductor switch element S1, a switch section formed by connecting a diode D2 in parallel to the semiconductor switch element S2, and a power supply terminal Vcc and a ground. It is configured to be connected in series with the terminal GND.

  Similarly, the second switch circuit unit 23 includes a switch unit in which a diode D3 is connected in parallel to the semiconductor switch element S3, and a switch unit in which a diode D4 is connected in parallel to the semiconductor switch element S4. The connection is made in series between Vcc and the ground terminal GND.

  Accordingly, the first switch circuit unit 22 and the second switch circuit unit 23 are connected in parallel between the power supply terminal Vcc and the ground terminal GND.

  Each of the semiconductor switches S1 to S4 can be energized in a direction from the power supply terminal Vcc side (positive side) toward the ground terminal GND side (negative side). Further, the direction (forward direction) in which each of the diodes D1 to D4 can be energized is a direction from the ground terminal GND side (negative electrode side) toward the power supply terminal Vcc side (positive electrode side).

  In the motor energization circuit 21A on the A phase side, the midpoint between the switch portion on the power supply terminal Vcc side and the switch portion on the ground terminal GND side of the first switch circuit portion 22 is in the motor drive circuit 20. It is electrically connected to an output terminal OUT1 connected to one end of the A-phase coil 2A.

  Further, the midpoint between the switch portion on the power supply terminal Vcc side and the switch portion on the ground terminal GND side of the second switch circuit portion 23 of the motor energization circuit 21A on the A phase side is the A phase coil inside the motor drive circuit 20. It is conducted to the output terminal OUT2 connected to the other end of 2A.

  In the B-phase side motor energization circuit 21B, the midpoint between the switch portion on the power supply terminal Vcc side and the switch portion on the ground terminal GND side of the first switch circuit portion 22 is in the motor drive circuit 20. It is electrically connected to an output terminal OUT3 connected to one end of the B-phase coil 2B.

  Further, the midpoint between the switch portion on the power supply terminal Vcc side and the switch portion on the ground terminal GND side of the second switch circuit portion 23 of the B-phase side motor energization circuit 21B is the B-phase coil in the motor drive circuit 20. It is conducted to the output terminal OUT4 connected to the other end of 2B.

  Since the motor energizing circuits 21A and 21B are configured as described above, both ends of the coils 2A and 2B of the respective phases are respectively connected to the power supply terminal Vcc or the ground terminal GND by the on / off control of the semiconductor switch elements S1 to S4. (As a result, it can be connected to the positive electrode of the DC power supply 10 via the power supply terminal Vcc or connected to the negative electrode of the DC power supply 10 via the ground terminal GND).

  The switching control unit 24 is electrically connected to the input terminals IN <b> 1 to IN <b> 4 inside the motor drive circuit 20. The switching control unit 24 controls on / off of the semiconductor switch elements S1 to S4 of the A-phase side motor energization circuit 21A according to a set of command signals input to the input terminals IN1 and IN2, and the input terminals IN3 and IN3. The circuit unit is configured to control on / off of the semiconductor switch elements S1 to S4 of the B-phase side motor energization circuit 21B in accordance with a set of command signals input to IN4.

  In this case, the switching control unit 24 controls the phase A side so that the outputs (potentials) of the output terminals OUT1 and OUT2 are in the state shown in FIG. 2 according to the set of command signals input to the input terminals IN1 and IN2. ON / OFF of the semiconductor switch elements S1 to S4 of the motor energization circuit 21A is controlled.

  Specifically, when the levels of the command signals input to the input terminals IN1 and IN2 are L level and L level, respectively, the switching control unit 24 switches all of the semiconductor switches S1 to S4 of the motor energization circuit 21A. By controlling to the off state, both the output terminals OUT1 and OUT2 are turned off. This state is a state where both ends of the A-phase coil 2A are disconnected from the positive electrode and the negative electrode of the DC power supply 10 (interrupted state).

  When the level of the command signal input to the input terminals IN1 and IN2 is H level and L level, respectively, the switching control unit 24 switches the semiconductor switch elements S1, S2, S3, and S4 of the motor energization circuit 21A. By controlling the on state, off state, off state, and on state, respectively, the output of the output terminal OUT1 is set to H level (high level), and the output of the output terminal OUT2 is set to L level (low level).

  In this state, one end of the A-phase coil 2A on the output terminal OUT1 side is connected to the positive electrode of the DC power supply 10 (positive connection state), and the other end of the A-phase coil 2A on the output terminal OUT2 side is the DC power supply. 10 is connected to the negative electrode (negative electrode connection state), and is a state in which a voltage for passing an excitation current is applied to the A-phase coil 2A from the output terminal OUT1 side to the output terminal OUT2 side.

  When the levels of the command signals input to the input terminals IN1 and IN2 are L level and H level, respectively, the switching control unit 24 switches the semiconductor switch elements S1, S2, S3, and S4 of the motor energizing circuit 21A. By controlling to an off state, an on state, an on state, and an off state, respectively, the output of the output terminal OUT1 is set to L level (low level), and the output of the output terminal OUT2 is set to H level (high level).

  In this state, one end on the output terminal OUT1 side of the A-phase coil 2A is connected to the negative electrode of the DC power supply 10 (negative connection state), and the other end on the output terminal OUT2 side of the A-phase coil 2A is the DC power supply. 10 is connected to the positive electrode (positive connection state), and is a state in which a voltage for applying an excitation current from the output terminal OUT2 side to the output terminal OUT1 side is applied to the A-phase coil 2A.

  When the level of the command signal input to the input terminals IN1 and IN2 is H level and H level, respectively, the switching control unit 24 switches the semiconductor switch elements S1, S2, S3, and S4 of the motor energizing circuit 21A. The outputs of both the output terminals OUT1 and OUT2 are set to L level (low level) by controlling the off state, the on state, the off state, and the on state, respectively.

  In this state, both ends of the A-phase coil 2A are connected (that is, short-circuited) to the same potential (ground potential in the present embodiment), so that the exciting current is supplied from the DC power supply 10 to the A-phase coil 2A. However, when the rotor (not shown) of the stepping motor 1 tries to rotate, a braking force is applied to the rotor.

  For the B-phase motor energization circuit 21B, the switching control unit 24 determines that the outputs (potentials) of the output terminals OUT3 and OUT4 are as shown in FIG. 2 according to the set of command signals input to the input terminals IN3 and IN4. The on / off state of the semiconductor switch elements S1 to S4 of the B phase side motor energization circuit 21B is controlled.

  In this case, the on / off control of the semiconductor switch elements S1 to S4 of the B-phase side motor energization circuit 21B is the same as the A-phase side motor energization circuit 21B. Therefore, the correspondence between the set of command signals input to the input terminals IN3 and IN4 and the output (potential) of the output terminals OUT3 and OUT4 is the same as the set of command signals input to the input terminals IN1 and IN2 and the output terminals OUT1 and OUT2. The correspondence relationship with the output (potential) of OUT2 is the same.

  The control unit 30 is constituted by a microcomputer or an electronic circuit unit including a CPU, RAM, ROM and the like. A voltage generated by the current detection resistor 12 is input to the control unit 30 via an amplifier 13. The voltage generated by the current detection resistor 12 is a voltage proportional to the current flowing through the resistor 12 (the current flowing from the DC power supply 10 to the stepping motor 1), and this is hereinafter referred to as a current detection signal Vi.

  The control unit 30 checks whether there is an abnormality such as disconnection or short circuit of the coils 2A and 2B of each phase as a function realized by executing a program to be installed or a function realized by a hardware configuration. An abnormality detection processing unit 31 that executes processing to be detected is provided.

  The abnormality detection processing unit 31 corresponds to the abnormality detection processing means in the present invention, and controls the motor energization circuits 21A and 21B to a predetermined operation state via the switching control unit 24 when the operation of the stepping motor 1 is stopped. However, the current detection signal Vi input from the current detection resistor 12 to the control unit 30 via the amplifier 13 is monitored. Then, the abnormality detection processing unit 31 detects the presence / absence of a circuit system abnormality by comparing the magnitude of the current detection signal Vi with a predetermined threshold value set in advance.

  In this case, in the present embodiment, the abnormality of the detection target due to the processing of the abnormality detection processing unit 31 is a short circuit of the coil 2A or 2B of each phase (short circuit between both ends of the coil 2A or 2B), or the coil 2A or 2B of each phase. Disconnection (or disconnection of the energization path between the DC power supply and each phase coil 2A or 2B), or a short circuit between specific ends of the coils 2A and 2B (specifically, the end on the OUT2 side of the coil 2A) And the end on the OUT3 side of the coil 2B).

  Next, the operation of the present embodiment (details of processing of the abnormality detection processing unit 31) will be described.

  During operation of the stepping motor 1, the control unit 30 generates a command signal so as to rotate the rotor (not shown) of the stepping motor 1 by, for example, a two-phase excitation method, and inputs the command signal to the motor drive circuit 20. Input to terminals IN1 to IN4.

  In this case, the command signal input to the input terminals IN1 to IN4 of the motor drive circuit 20 is generated in the pattern shown in FIG. 3 (a) or FIG. 3 (b). 3A shows a command signal pattern when the rotor of the stepping motor 1 is rotated in the counterclockwise direction, and FIG. 3B is a rotation of the rotor of the stepping motor 1 in the clockwise direction. The pattern of the command signal in the case is shown.

  In response to the command signal, the switching control unit 24 controls the motor energization circuits 21A and 21B for each phase. As a result, the coils 2A and 2B of the phases A and B are energized from the DC power supply 10 so that the direction of the current is periodically switched. Further, the switching of the direction of the current of the coil 2A (switching of a set of command signals input to the input terminals IN1 and IN2) and the switching of the direction of the current of the coil 2B (switching of the command signal input to the input terminals IN3 and IN4). (Switching of sets) is performed at different timings.

  Further, the control unit 30 causes the abnormality detection processing unit 31 to execute processing for detecting the presence / absence of an abnormality while the operation of the stepping motor 1 is stopped.

  In the present embodiment, the processing of the abnormality detection processing unit 31 performs stepping, for example, when there is a request for operation of the stepping motor 1 (when starting operation of a water heater equipped with the stepping motor 1, a gas stove, or the like). It is executed immediately before the actual operation of the motor 1 is started.

  Specifically, the abnormality detection processing unit 31 of the control unit 30 sets the period of each processing step of STEP 1, 2, 3, 4, and 5 shown in FIG. 4A (default) before the operation of the stepping motor 1 is started. In this time interval), a set of command signals having the illustrated pattern is sequentially input to the input terminals IN1 to IN4 of the motor drive circuit 20.

  Note that the processing of STEP 1 to 4 corresponds to the second abnormality detection processing in the present invention, and the processing of STEP 5 corresponds to the first abnormality detection processing in the present invention.

  In STEP1, an H level command signal is input only to the input terminal IN1, and an L level command signal is input to the other input terminals IN2, IN3, and IN4.

  At this time, the A-side motor energization circuit 21A is controlled by the switching control unit 24 so that the excitation current from the output terminal OUT1 side to the OUT2 side is energized from the DC power supply 10 to the A-phase coil 2A. Specifically, the semiconductor switch elements S1 to S4 of the motor energization circuit 21A are turned on, off, off, and on, respectively (as a result, one end on the OUT1 side of the A-phase coil 2A is in a positive connection state and the other end on the OUT2 side is in a negative connection. Control).

  Then, the semiconductor switch elements S1 to S4 of the B-phase side motor energization circuit 21B are controlled so as to be turned off. For this reason, both ends of the B-phase coil 2 </ b> B are disconnected from the DC power supply 10.

  In STEP2, an H level command signal is input only to the input terminal IN2, and an L level command signal is input to the other input terminals IN1, IN3, and IN4.

  At this time, the A phase side motor energizing circuit 21A performs switching control so that the DC phase power supply 10 energizes the A phase coil 2A with an exciting current (exciting current opposite to STEP 1) from the output terminal OUT2 side to the OUT1 side. Controlled by the unit 24. Specifically, the semiconductor switch elements S1 to S4 of the motor energizing circuit 21A are turned off, on, on, and off, respectively (as a result, one end on the OUT2 side of the A phase coil 2A is in a positive connection state and the other end on the OUT1 side is in a negative connection. Control). Then, as in STEP 1, both ends of the B-phase coil 2 </ b> B are disconnected from the DC power supply 10.

  In STEP 3, an H level command signal is input only to the input terminal IN3, and an L level command signal is input to the other input terminals IN1, IN2, and IN4.

  At this time, the B phase side motor energization circuit 21B is controlled by the switching control unit 24 so that the B phase coil 2B is energized from the DC power source 10 with an exciting current from the output terminal OUT3 side to the OUT4 side. Specifically, the semiconductor switch elements S1 to S4 of the motor energization circuit 21B are turned on, off, off, and on, respectively (as a result, one end on the OUT3 side of the B-phase coil 2B is in a positive connection state and the other end on the OUT4 side is in a negative connection. Control).

  The semiconductor switch elements S1 to S4 of the A-phase side motor energization circuit 21A are controlled so as to be turned off. For this reason, both ends of the A-phase coil 2 </ b> A are disconnected from the DC power supply 10.

  In STEP 4, an H level command signal is input only to the input terminal IN4, and an L level command signal is input to the other input terminals IN1, IN2, and IN3.

  At this time, the B-phase side motor energizing circuit 21B performs switching control so that the B-phase coil 2B is energized with the exciting current (exciting current opposite to STEP 3) from the output terminal OUT4 side to the OUT3 side. Controlled by the unit 24. Specifically, the semiconductor switch elements S1 to S4 of the motor energization circuit 21B are turned off, on, on, and off, respectively (as a result, one end on the OUT4 side of the B-phase coil 2B is in a positive connection state and the other end on the OUT3 side is in a negative connection. Control). As in STEP 3, both ends of the A-phase coil 2 </ b> A are disconnected from the DC power supply 10.

  As described above, in STEP 1 to STEP 4, only one of the A-phase coil 2 </ b> A and the B-phase coil 2 </ b> B is energized in one direction, and both ends of the other coil 2 </ b> A or 2 </ b> B are connected to the DC power source 10. The motor energization circuits 21A and 21B are controlled so as to be disconnected from each other (the both ends are electrically open ends). In each of STEP1 to STEP4, the combination of the coil 2A or 2B to be energized and the energization direction are different from each other.

  Here, in each of STEP 1 to 4, when energization to the coil 2 </ b> A or 2 </ b> B to be energized is normally performed, an excitation current having a magnitude within a predetermined range is energized via the current detection resistor 12. It flows to the target coil 2A or 2B.

  For this reason, the magnitude of the current detection signal Vi input from the current detection resistor 12 to the control unit 30 is, for example, as shown in FIG. 4B, a predetermined first threshold TH1 and second threshold TH2 (<TH1 ).

  On the other hand, when the disconnection of the A-phase coil 2A or the B-phase coil 2B (or the disconnection of the energization path between the coil 2A or the coil 2B and the DC power supply 10) occurs, it is energized in any one of STEP1 to STEP4. Since no current flows through the coil 2A or 2B, the magnitude of the current detection signal Vi becomes zero (<TH2).

  For example, when the disconnection of the A-phase coil 2A (or the disconnection of the energization path between the coil 2A and the DC power supply 10) occurs, the current detection signal Vi is detected in STEPs 1 and 2 as shown in FIG. Is smaller than the second threshold value TH2.

  This is the same even when a disconnection of the B-phase coil 2B (or disconnection of the energization path between the coil 2B and the DC power supply 10) occurs. In this case, in STEPs 3 and 4, the magnitude of the current detection signal Vi is smaller than the second threshold value TH2.

  In addition, when a short circuit occurs between the A phase coil 2A or the B phase coil 2B (between the output terminals OUT1 and OUT2 or between OUT3 and OUT4), power is supplied from the DC power supply 10 in any one of STEP1 to STEP4. Since current flows through a short-circuit path that bypasses the target A-phase coil 2A or B-phase coil 2B, the current detection resistor Vi has a magnitude greater than the first threshold TH1 in the current detection resistor 12. Excessive current flows.

  For example, when a short circuit occurs in the B-phase coil 2B, as shown in FIG. 4D, in STEPs 3 and 4, the magnitude of the current detection signal Vi becomes larger than the first threshold value TH1.

  This is the same even when a short circuit of the A-phase coil 2A occurs. In this case, in STEPs 1 and 2, the magnitude of the current detection signal Vi is larger than the first threshold value TH1.

  Therefore, the abnormality detection processing unit 31 determines whether the A-phase coil 2A or the B-phase coil 2B to be energized when the magnitude of the current detection signal Vi exceeds the predetermined first threshold value TH1 in any one of STEP1 to STEP4. It is determined that an abnormality has occurred due to a short circuit between the output terminals OUT1 and OUT2 or between OUT3 and OUT4.

  Further, in any of STEP 1 to STEP 4, when the abnormality detection processing unit 31 has a current detection signal Vi that is less than a predetermined second threshold value TH2, the A-phase coil 2A to be energized or It is determined that an abnormality has occurred due to disconnection of the B phase coil 2B (or disconnection of the energization path between the A phase coil 2A or B phase coil 2B to be energized and the DC power source 10).

  The first threshold value TH1 and the second threshold value TH2 are set in advance based on experiments or the like. In this case, the first threshold value TH1 corresponds to the first threshold value in the present invention, and also corresponds to the second threshold value in the present invention. The second threshold TH2 corresponds to the third threshold in the present invention.

  Next, in STEP5 following STEP1-4, an L level command signal is input to one of the input terminals IN1, IN4, for example, the input terminal IN1, and the remaining three input terminals IN2, IN3, IN4 are at the H level. Command signal is input.

  At this time, the switching control unit 24 controls the A phase side motor energization circuit 21A so that the excitation current flowing from the output terminal OUT2 side to the OUT1 side is energized from the DC power source 10 to the A phase coil 2A. Specifically, the semiconductor switch elements S1 to S4 of the motor energizing circuit 21A are turned off, on, on, and off, respectively (as a result, one end on the OUT2 side of the A phase coil 2A is in a positive connection state and the other end on the OUT1 side is in a negative connection. Control).

  Further, the semiconductor switch elements S1 to S4 of the B-phase side motor energization circuit 21B are controlled to be off, on, off, and on, respectively. That is, the motor energization circuit 21B is controlled so that both ends of the B-phase coil 2B are in the negative electrode connection state.

  In the present embodiment, since the output terminals OUT2 and OUT3 are adjacent to each other, a short circuit between the output terminals OUT2 and OUT3 (the end of the A-phase coil 2A on the OUT2 side) due to defective solder or adhesion of dust or the like. There may be a case where a short circuit between the B3 coil 2B and the end on the OUT3 side occurs.

  Here, even if a short circuit occurs between the output terminals OUT2 and OUT3, a short circuit of the A phase coil 2A or the B phase coil 2B, or a disconnection of the A phase coil 2A or the B phase coil 2B (or the coil 2A or 2B) If no disconnection between the DC power source 10 and the DC power source 10 occurs, a current normally flows through the coil 2A or 2B to be energized in STEP 1 to STEP 4. Therefore, in this situation, in STEPs 1 to 4, the magnitude of the current detection signal Vi falls between the first threshold value TH1 and the second threshold value TH2. Therefore, the abnormality detection processing unit 31 does not detect the occurrence of abnormality in STEPs 1 to 4.

  On the other hand, in STEP5, one end on the OUT2 side of the A phase coil 2A is in a positive connection state, and one end on the OUT3 side of the B phase coil 2B is in a negative connection state. For this reason, when a short circuit occurs between the output terminals OUT2 and OUT3, a current flows through the short-circuit path bypassing the A-phase coil 2A from the DC power supply 10. Accordingly, an excessive current flows through the current detection resistor 12 so that the magnitude of the current detection signal Vi is larger than the first threshold value TH1.

  For this reason, when a short circuit occurs between the output terminals OUT2 and OUT3, as shown in FIG. 4E, in STEP5, the magnitude of the current detection signal Vi becomes larger than the first threshold value TH1.

  Therefore, when the magnitude of the current detection signal Vi is within the range between the first threshold value TH1 and the second threshold value TH2 in STEP1 to STEP4, the abnormality detection processing unit 31 determines that the current detection signal Vi in STEP5. When the size exceeds the first threshold TH1, a short circuit between the output terminals OUT2 and OUT3 (in other words, between the OUT2 side end of the A phase coil 2A and the OUT3 side end of the B phase coil 2B) It is determined that an abnormality has occurred due to a short circuit.

  Note that a short circuit of the A phase coil 2A, a disconnection of the A phase coil 2A (or a disconnection of the energization path between the A phase coil 2A and the DC power supply 10), and a short circuit between the output terminals OUT2 and OUT3 have occurred. If not, in STEP 5, the current normally flows only through the A-phase coil 2 </ b> A regardless of whether the B-phase coil 2 </ b> B side is short-circuited or disconnected. Therefore, in this case, the magnitude of the current detection signal Vi falls within the range between the first threshold TH1 and the second threshold TH2, as illustrated in FIG. 4B or 4D.

  Supplementally, even if the short circuit between the output terminals OUT2 and OUT3 has not occurred, if the short circuit of the A-phase coil 2A has occurred, in STEP5, the current detection signal Vi is the same as in STEP1 and STEP2. Is larger than the first threshold value TH1.

  Furthermore, even when the short circuit between the output terminals OUT2 and OUT3 does not occur, the disconnection of the A-phase coil 2A (or the disconnection of the energization path between the A-phase coil 2A and the DC power supply 10) occurs. In STEP5, as in STEP1 and STEP2, the magnitude of the current detection signal Vi is smaller than the second threshold value TH1 (see FIG. 4C).

  As described above, the abnormality detection processing unit 31 detects the presence or absence of an abnormality due to a short circuit or disconnection by executing the processes of STEP 1 to 5 before starting the operation of the stepping motor 1.

  Thereby, when the operation of the stepping motor 1 is stopped, the coils 2A and 2B of each phase are short-circuited, or the coils 2A and 2B of each phase are disconnected (or the energization path between the coil 2A or 2B and the DC power supply 10). In addition to detecting an abnormality due to disconnection, an abnormality due to a short circuit between the output terminals OUT2 and OUT3 (a short circuit between specific ends of the coils 2A and 2B) can be detected.

  And control unit 30 starts the actual driving | operation of stepping motor 1, when abnormality is not detected by abnormality detection process part 31 in any of STEP1-5. In addition, when an abnormality is detected by the abnormality detection processing unit 31 in any of STEP 1 to 5, the control unit 30 outputs an error alarm or the like.

  In the processing of the abnormality detection processing unit 31 in the present embodiment, when the above short circuit or disconnection does not occur, the direct current is applied to only one of the A phase coil 2A and the B phase coil 2B in each of STEP1 to STEP5. Since the exciting current is supplied from the power supply 10, the rotational position of the rotor of the stepping motor 1 in each of STEP 1 to 5 can be accurately defined at a position that can be specified by the control unit 30. For this reason, the rotation control of the rotor after the operation of the stepping motor 1 can be appropriately performed with high reliability.

  Next, some modifications of the embodiment described above will be described.

  In the embodiment described above, instead of inputting the L level command signal to the input terminal IN1 in STEP 5, the L level command signal is input to the input terminal IN4, and the remaining three input terminals IN1, IN2, IN3 are input. An H level command signal may be input. In this case, one end on the OUT3 side of the B phase coil 2B is in a positive connection state (H level state), the other end on the OUT4 side is in a negative connection state (L level state), and both ends of the A phase coil 2A are in a negative connection state. Motor energization circuits 21A and 21B are controlled so as to be in the (L level state).

  Even in this case, if a short circuit occurs between the output terminals OUT2 and OUT3, a current flows from the DC power source 10 through the short circuit path in STEP5, and the current detection signal Vi exceeds the first threshold value TH1.

  In the above embodiment, the presence or absence of a short circuit between the output terminals OUT2 and OUT3 is detected in STEP 5, but instead of this detection or in addition to this detection, a short circuit between the output terminals OUT1 and OUT3 is detected. It is also possible to detect the presence or absence, the presence or absence of a short circuit between OUT1 and OUT4, or the presence or absence of a short circuit between OUT2 and OUT4.

  When detecting the presence or absence of a short circuit between the output terminals OUT1 and OUT3, for example, the command signals input to the input terminals IN1 to IN4 are set to the H level, the L level, the H level, and the H level, respectively (and thus OUT1 to OUT4). The motor energization circuits 21A and 21B may be controlled so that the respective outputs (potentials) are H level, L level, L level, and L level).

  Alternatively, the command signals input to the input terminals IN1 to IN4 are set to H level, H level, H level, and L level, respectively (and the respective outputs (potentials) of OUT1 to OUT4 are set to L level, L level, and H level, respectively). , L level) may be used to control the motor energization circuits 21A and 21B.

  When detecting the presence or absence of a short circuit between the output terminals OUT1 and OUT4, for example, the command signals input to the input terminals IN1 to IN4 are set to the H level, the L level, the H level, and the H level, respectively. Motor energization circuits 21A and 21B may be controlled so that respective outputs (potentials) of -OUT4 are set to H level, L level, L level, and L level).

  Alternatively, the command signals input to the input terminals IN1 to IN4 are set to the H level, the H level, the L level, and the H level, respectively (therefore, the outputs (potentials) of the OUT1 to OUT4 are set to the L level, the L level, and the L level, respectively. , H level), the motor energization circuits 21A and 21B may be controlled.

  When detecting the presence or absence of a short circuit between OUT2 and OUT4, for example, command signals input to the input terminals IN1 to IN4 are set to L level, H level, H level, and H level, respectively (and thus OUT1 to OUT4). The motor energization circuits 21A and 21B may be controlled so that the respective outputs (potentials) are set to L level, H level, L level, and L level).

  Alternatively, the command signals input to the input terminals IN1 to IN4 are set to the H level, the H level, the L level, and the H level, respectively (therefore, the outputs (potentials) of the OUT1 to OUT4 are set to the L level, the L level, and the L level, respectively. , H level), the motor energization circuits 21A and 21B may be controlled.

  If the motor energization circuits 21A and 21B for each phase are configured so that both the semiconductor switches S1 and S3 on the power supply terminal Vcc side can be simultaneously turned on, in STEP 5, the A phase The motor energization circuits 21A and 21B are controlled so that both ends of the coil 2A are in a positive connection state, one end on the OUT3 side of the B-phase coil 2B is in a negative connection state, and the other end on the OUT4 side is in a positive connection state. Also good.

  Alternatively, the motor energization circuits 21A and 21B are controlled so that both ends of the B-phase coil 2B are in a positive connection state, one end on the OUT2 side of the A-phase coil 2B is in a negative connection state, and the other end on the OUT1 side is in a positive connection state. You may make it do.

  Even in this case, it is possible to detect the presence or absence of a short circuit between the output terminals OUT2 and OUT3.

  The same applies to the case where the presence or absence of a short circuit between the output terminals OUT1 and OUT3, the presence or absence of a short circuit between OUT1 and OUT4, or the presence or absence of a short circuit between OUT2 and OUT4 is detected.

  Moreover, in the said embodiment, although the process of STEP1-5 was performed in this order in the process of the abnormality detection process part 31, the order of these processes may be arbitrary orders. For example, the processing of STEP1 to STEP4 may be executed after the processing of STEP5.

  Moreover, in the said embodiment, although the process of the abnormality detection process part 31 was performed before the driving | operation start of the stepping motor 1, the process of the abnormality detection process part 31 was carried out at the arbitrary timings during the operation stop of the stepping motor 1. You may make it perform.

  Moreover, in the said embodiment, although motor energization circuit 21A, 21B and the switching control part 24 were comprised by single IC, you may comprise these separately on a circuit board.

  Moreover, in the said embodiment, although the negative electrode of DC power supply 10 was earth | grounded, you may comprise so that the positive electrode of DC power supply 10 may be earth | grounded.

  DESCRIPTION OF SYMBOLS 1 ... Stepping motor, 2A ... A phase coil (1st phase coil), 2B ... B phase coil (2nd phase coil), 10 ... DC power supply, 12 ... Current detection resistance (current detection means), 21A, 21B: Motor energization circuit, 22: First switch circuit section, 23: Second switch circuit section, 31: Abnormality detection processing section (abnormality detection processing means), STEP1-4: Second abnormality detection processing, STEP5: First abnormality Detection process.

Claims (5)

Abnormality of a circuit system comprising a stepping motor having a two-phase coil of a first phase and a second phase and a motor energization circuit connected to each phase coil to energize each phase coil from a DC power supply An abnormality detection device for detecting
The motor energization circuit corresponding to each coil of each phase has a positive connection state in which one end of the coil to which the motor energization circuit is connected is connected to the positive electrode of the DC power supply and a negative connection that is connected to the negative electrode of the DC power supply. A first switch circuit portion configured to be controllable to any one of a state and a cut-off state that is cut off from the positive electrode and the negative electrode of the DC power supply, and a positive electrode that connects the other end of the coil to the positive electrode of the DC power supply A second switch circuit unit configured to be controllable to any one of a connection state, a negative electrode connection state to be connected to the negative electrode of the DC power source, and a cutoff state to be disconnected from the positive electrode and the negative electrode of the DC power source. ,
Current detection means for generating an output corresponding to the current flowing from the DC power supply when energizing the coils of each phase;
An abnormality detection processing means for executing processing for detecting the presence or absence of abnormality of the circuit system based on the output of the current detection means while controlling the motor energization circuit;
When the operation of the stepping motor is stopped, the abnormality detection processing means is configured such that one of the first switch circuit portion and the second switch circuit portion of the motor energization circuit connected to the first phase coil is in a positive connection state and the other is Controlling to a negative electrode connection state, and controlling both the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the second phase coil to a positive electrode connection state or a negative electrode connection state; The circuit system abnormality of the stepping motor is configured to execute a first abnormality detection process for detecting the presence or absence of abnormality of the circuit system based on the output of the current detection means Detection device. In the step detection motor circuit system abnormality detection device according to claim 1,
The motor energization circuit connected to the first phase coil and the motor energization circuit connected to the second phase coil connect one end of both ends of the first phase coil. The first phase side connection terminal and the second phase side connection terminal for connecting one end of the both ends of the second phase coil are provided adjacent to each other,
In the first abnormality detection process, one of the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the first phase coil is controlled to be in a positive connection state and the other is controlled in a negative connection state. And controlling both the first switch circuit unit and the second switch circuit unit of the motor energization circuit connected to the second phase coil to a positive connection state or a negative connection state by the control. One of the end of the first phase coil connected to the first phase side connection terminal and the end of the second phase coil connected to the second phase side connection terminal is the positive electrode of the DC power supply. And the other is connected to the negative electrode of the DC power supply, and includes at least processing for detecting the presence or absence of abnormality in the circuit system based on the output of the current detection means. Steppi Abnormality detection apparatus for circuit system Gumota. In the abnormality detection apparatus for the circuit system of the stepping motor according to claim 1 or 2,
The abnormality detection processing means determines that there is an abnormality in the circuit system when the magnitude of the current indicated by the output of the current detection means is larger than a predetermined first threshold value in the first abnormality detection processing. An abnormality detection device for a circuit system of a stepping motor, characterized in that it is configured as follows. In the abnormality detection apparatus of the circuit system of the stepping motor of any one of Claims 1-3,
The abnormality detection processing means is one of the first switch circuit portion and the second switch circuit portion of the motor energization circuit connected to the coil of one of the first phase and the second phase when the stepping motor is stopped. Controlling the first and second switch circuit portions of the motor energization circuit connected to the coil of the other phase to a cut-off state. The stepping motor circuit system is further configured to further execute a second abnormality detection process for detecting the presence or absence of abnormality of the circuit system based on the output of the current detection means. Anomaly detection device. In the step detection motor circuit system abnormality detection device according to claim 4,
In the second abnormality detection process, the abnormality detection processing means has a predetermined third value smaller than the second threshold value when the magnitude of the current indicated by the output of the current detection means is larger than the predetermined second threshold value. An apparatus for detecting an abnormality in a circuit system of a stepping motor, wherein the abnormality detection device is configured to determine that there is an abnormality in the circuit system when smaller than a threshold value.