JP2018133835A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller which can diagnose a disconnection state between a motor and an inverter circuit while controlling energization quantity by using an ordinary current sensor installed between the motor and the inverter circuit.SOLUTION: A motor controller comprises an inverter circuit 200 driving a three-phase AC motor 100 and a controller 600 controlling the inverter circuit. The controller detects a first current value of a current flowing to the three-phase AC motor by turning on one of high voltage side and low voltage side arms of a second phase and a third phase and turning on the other of high voltage side and low voltage side arms of a first phase for a predetermined time, and diagnoses a disconnection state between the three-phase AC motor and the inverter circuit on the basis of the first current value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device having a function of diagnosing a disconnection state on a motor side.

  As a technique for diagnosing an open phase between the inverter circuit included in the motor control device and the motor driven by the inverter circuit, that is, a disconnection state, a conventional technique as described in Patent Document 1 is known.

  In this conventional technology, before starting the three-phase motor, the operation of supplying current to one phase and sucking current from the other two phases is executed for each phase, and from the inverter circuit to the DC / DC converter circuit for each operation. The presence or absence of abnormality is determined by determining whether or not a direct current flows. Furthermore, after starting, when driving current is supplied from the inverter circuit to the three-phase motor to rotate the three-phase motor, the DC current is continuously detected, and if there is no open phase, the motor rotates once. Whether or not there is an abnormality is determined by determining the number of sawtooth peaks that appear six in the cycle and decrease to two when the phase is lost. When it is determined that there is an abnormality, the motor drive is stopped once, the disconnection detection process same as that before the start is executed, the phase in which the phase failure occurs is confirmed, and the abnormality is notified.

JP 2013-1332099 A

In the above-described conventional technology, it is necessary to newly install a direct current sensor in order to detect a direct current flowing from the inverter circuit to the direct current / direct current conversion circuit. Furthermore, since the amount of current supplied to the motor is not controlled, the motor may rotate during diagnosis at startup (before traveling), and vibration, noise, or unintended traveling may occur.
Therefore, the present invention provides a motor control device capable of diagnosing a disconnection state between a motor and an inverter circuit while controlling an energization amount using a normal current sensor installed between the motor and the inverter circuit.

  In order to solve the above problems, a motor control device according to the present invention includes an inverter circuit that drives a three-phase AC motor, and a control device that controls the inverter circuit, and the control device includes a second phase and a third phase. While one arm on the high voltage side and the low voltage side is turned on, the other arm on the high voltage side and the low voltage side in the first phase is turned on for a predetermined time to flow to the three-phase AC motor. A first current value of the current is detected, and a disconnection state between the three-phase AC motor and the inverter circuit is diagnosed based on the first current value.

  In order to solve the above problems, a motor control device according to the present invention includes an inverter circuit that drives a three-phase AC motor and a control device that controls the inverter circuit, and the control device includes the second phase and the second phase. A three-phase AC motor that turns on the other arm on the high voltage side and the low voltage side in the first phase for a predetermined time while turning on one arm on the high voltage side and the low voltage side in the three phases. The first current value of the current flowing in the first phase and the third phase is detected, and one arm on the high voltage side and the low voltage side in the first phase and the third phase is turned on, while the high voltage side and the low voltage in the second phase are The other arm on the voltage side is turned on for a predetermined time, the second current value of the current flowing through the three-phase AC motor is detected, and the three-phase is determined based on the first current value and the second current value. AC motor and the inverter circuit It diagnoses disconnection state between.

According to the present invention, one of the high voltage side and the low voltage side in the other one phase is turned on while the other arm on the high voltage side and the low voltage side in the two phases is turned on. The arm is turned on for a predetermined time, and at this time, the disconnection state is diagnosed based on the current flowing through the three-phase AC motor. Diagnose disconnection.

  Problems, configurations, and effects other than those described above will become apparent from the following description of embodiments.

1 is a configuration diagram of a motor control apparatus that is Embodiment 1. FIG. It is a flowchart which shows the processing operation of the control apparatus in a disconnection diagnosis. It is an example of the ON timing and ON time of an energized phase. An example of the relationship between the ON time of the upper arm of the U phase and the V phase and the DC input voltage in the inverter circuit is shown. The energized state of the upper and lower arms of the UVW phase when the U phase and V phase are energized is shown. It is a circuit diagram which shows the electric current route at the time of U phase energization and V phase energization. The example of a waveform of the UVW phase electric current at the time of U phase energization and V phase energization is shown. The relationship between the diagnostic result of a disconnection state and the electric current of each phase at the time of UV phase energization is shown. An example of the ON timing and ON time of the energized phase at the time of disconnection diagnosis in Example 2 is shown. The electric current of each phase at the time of U-phase electricity supply in Example 2 is shown.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below using Examples 1 and 2 with reference to the drawings. In each figure, the same reference numerals indicate the same constituent elements or constituent elements having similar functions.

  FIG. 1 is a configuration diagram of a motor control apparatus that is Embodiment 1 of the present invention.

  As shown in FIG. 1, in this embodiment, the inverter circuit 200 and the battery 400 are connected to each other to form a closed circuit. The inverter circuit 200 constitutes a main circuit of a so-called voltage source inverter. In the motor control apparatus of the present embodiment, the DC power of the battery 400 is converted into AC power by the inverter circuit 200, and the motor 100 is energized by the AC power output from the inverter circuit 200. Further, as will be described later, the motor control apparatus according to the present embodiment energizes two phases of the three phases of the motor 100, in this embodiment, the U phase and the V phase, by the inverter circuit 200, and the motor 100 and the inverter circuit. A diagnostic function for determining which phase between 200 is disconnected in a relatively short time is provided.

  The motor 100 is a power source of a hybrid vehicle or an electric vehicle, and is a three-phase AC synchronous motor driven by three-phase AC power. In this embodiment, motor 100 is a permanent magnet synchronous motor having a rotor provided with permanent magnets and a stator having three-phase windings of U phase, V phase and W phase. A rotational force is generated in the rotor by the interaction between the rotating magnetic field generated by the alternating current flowing through each winding and the permanent magnet magnetic flux.

  In this embodiment, the U-phase winding, V-phase winding, and W-phase winding of the motor 100 are Y (or star) connected.

  The inverter circuit 200 includes six semiconductor switching elements (in FIG. 1, insulated gate bipolar transistors (IGBTs)) and is connected in series two by two, and upper and lower arms for three phases (U phase, V phase, W phase) Configure. The series connection points of the high-voltage side and low-voltage side arms, ie, the upper and lower arms, for the three phases are respectively connected to the U-phase winding, V-phase winding and W-phase of the motor 100 via the AC power supply cable 300. Electrically connected to the winding. Both ends of the upper and lower arms are electrically connected to the battery 400 via a DC power supply cable 500. In the inverter circuit 200, a smoothing capacitor 800 is connected to the DC input side. A diode is electrically connected in antiparallel to each semiconductor switching element (between the collector and emitter of the IGBT in FIG. 1). This diode operates as a so-called freewheeling diode.

  In the inverter circuit 200, the semiconductor switching element performs a switching operation, whereby the DC power input from the battery 400 is converted into AC power, and this AC power is output to the motor 100 from the series connection point of the upper and lower arms. Smoothing capacitor 800 stabilizes the operation of inverter circuit 200 by suppressing fluctuations in the input side voltage associated with the switching operation.

  The battery 400 is a secondary battery such as a nickel metal hydride battery or a lithium ion battery. In this embodiment, the terminal voltage of the battery 400 is a relatively high voltage of about 100V to 400V.

  The control device 600 outputs a control signal (PWM signal) to the control terminal (in FIG. 1, the gate terminal of the IGBT) of each semiconductor switching element in the inverter circuit 200, and controls each semiconductor switching element, whereby the motor The torque and speed of the motor 100 are controlled by controlling the current supplied to the motor 100. In the present embodiment, the control device 600 sets iu, iv, iw to current command values for obtaining a desired torque or speed based on the three-phase alternating current values iu, iv, iw detected by the current sensor 700. Each semiconductor switching element is controlled to approach.

  In FIG. 1, for the sake of simplicity, a single current sensor 700 represents a sensor that detects a three-phase alternating current.

  Furthermore, as will be described later, control device 600 diagnoses a disconnection state between motor 100 and inverter circuit 200 based on three-phase AC current values iu, iv, and iw detected by current sensor 700.

  Note that the control device 600 includes an arithmetic processing device such as a microcomputer, and the arithmetic processing device performs processing operations according to a predetermined program, thereby controlling the torque and speed of the motor 100, and the motor 100 and the inverter circuit 200. Diagnose the disconnection state between the two.

  Next, the disconnection diagnosis between the motor 100 and the inverter circuit 200 before starting the motor (that is, before starting the running of the hybrid vehicle or the electric vehicle) by the control device 600 will be described.

  FIG. 2 is a flowchart showing the processing operation of the control device 600 in the disconnection diagnosis of this embodiment.

  In step S1000, the processing operation starts when the inverter circuit 200 is activated.

  Next, in step S <b> 1001, it is determined whether a high voltage (DC voltage) is input from the battery 400 to the inverter circuit 200. In this determination, it is determined whether the DC voltage exceeds a predetermined threshold value, or it is determined whether a high voltage relay (not shown) is ON based on an ON / OFF signal of the high voltage relay. Here, the high voltage relay is connected between the inverter circuit 200 and the battery 400. Note that the DC voltage is detected at both ends of the smoothing capacitor 800 and input to the control device 600, for example.

  Further, in step S1001, it is determined whether the rotational speed of the motor 100 is smaller than a predetermined threshold before the motor 100 is energized. That is, it is determined whether the motor is before starting, that is, before starting running. The rotational speed of the motor 100 is detected by a known means such as a rotary encoder or a resolver.

  If it is determined in step S1001 that a high voltage (DC voltage) is input to the inverter circuit 200 and it is determined that the motor has not been started (YES in S1001), then step S1002 is executed, and so on. Otherwise (NO in S1001), the determination process in step S1001 is repeatedly executed.

  In step S1002, the duty of the U phase and the V phase, that is, the ON time corresponding to the ON timing and the DC voltage is set. Then, at each current detection timing for disconnection diagnosis in one disconnection diagnosis period, U-phase energization or V-phase energization is set according to Duty. Thereby, the U phase and the V phase are sequentially energized in one disconnection diagnosis period. In the case of U-phase energization, only the U-phase upper arm of the three-phase upper arm is turned on, and only the V-phase and W-phase of the three-phase lower arm are turned on. In the case of V-phase energization, only the upper arm of the V phase among the upper arms for the three phases is turned on, and only the U phase and the W phase are turned on among the lower arms for the three phases. The duty is set so that the energization amount to the motor is an energization amount that maintains the state before the motor 100 is started. Thereby, at the time of disconnection diagnosis, the rotation of the motor is suppressed, and vibration, abnormal noise, unintended traveling, and the like are prevented.

  Next, in step S1003, in order to detect the presence or absence of disconnection, it is determined whether the absolute values of the current values iu, iv, and iw of the U phase, V phase, and W phase exceed a predetermined threshold value. If it is determined that the absolute value of any of the current values iu, iv, iw exceeds any of the predetermined threshold values (YES in S1003), that is, if it is estimated that there is no disconnection, then step S1004 is executed. Is done. If it is determined that the absolute values of all current values do not exceed the threshold (NO in S1003), that is, if it is estimated that there is a disconnection, step S1005 is executed next.

  In step S1004, among the counters for the OK flag of each phase vCnt_iu, vCnt_iv, vCnt_iw, the counter of the phase determined in step S1003 that the absolute value of the current value exceeds the predetermined threshold value is incremented. That is, in this step S1004, for each phase, the number of times that it is energized in one disconnection diagnosis period, that is, no disconnection is counted. After step S1004 is executed, next step S1005 is executed.

  In step S1005, the energization time counter vCnt_Ripoff is incremented. The elapsed time of current detection, that is, disconnection diagnosis is monitored by the count value of the energization time counter. After step S1005 is executed, next step S1006 is executed.

  In step S1006, it is determined whether the energization time counter vCnt_Ripoff exceeds a predetermined threshold. That is, it is determined whether one disconnection diagnosis period has ended. When it is determined that the energization time counter vCnt_Ripoff exceeds a predetermined threshold (YES in step S1006), next, step S1007 is executed. On the other hand, if it is determined that it has not exceeded (NO in step S1006), that is, if it is determined that the disconnection diagnosis period is still in progress, the process returns to step S1002, and the processes in and after step S1002 are repeatedly executed.

  In step S1007, based on the count value of the OK flag counter for each phase, the disconnection state, that is, the presence / absence of an abnormality, the disconnected phase, and the like are determined. First, when all of the OK flag counters vCnt_iu, vCnt_iv, and vCnt_iw are equal to or greater than a predetermined threshold, it is determined that there is no abnormality (no disconnection in all phases) because all three phases are energized. Next, when only vCnt_iu is smaller than the threshold value, it is determined that only the U phase is not energized, and the U phase is open (U phase disconnection). Similarly, when only vCnt_iv is smaller than the threshold value, it is determined that only the V phase is not energized and the V phase is open (V phase disconnection). If only vCnt_iw is smaller than the threshold value, it is determined that only the W phase is not energized, and the W phase is open (W phase disconnection). In step S1007, if the count value of the OK flag counter is not in any of the above cases, it is assumed that 2 phases or 3 phases (all phases) of the U phase, V phase and W phase are not energized. Phase or three-phase open (two-phase or three-phase disconnection) is determined.

  FIG. 3 is an example of the ON timing and ON time of the energized phase set in step S1002 of FIG.

  In the example of FIG. 3, the U-phase is turned on at Timing = 0 [ms], kept on for an on time of 0.1 ms (100 μs), and then turned off. The V-phase is turned on 5 ms after the U-phase is turned on (Timing = 5 [ms] in FIG. 3), and is turned on after the ON time is 0.1 ms (100 μs). The U-phase ON period is an ON period of the U-phase upper arm semiconductor switching element, that is, a period during which an ON signal is applied to the control terminal of the semiconductor switching element (in this embodiment, the gate terminal of the IGBT). The V-phase ON period is an ON period of the V-phase upper arm semiconductor switching element, that is, a period in which an ON signal is applied to the control terminal of the semiconductor switching element (in this embodiment, the gate terminal of the IGBT). Further, as shown in FIG. 3, the W phase is not turned ON.

  In addition, even after the U and V phase upper arms are turned off, the circulating current can flow. Therefore, in this embodiment, the ON period of the upper arm and the period in which the circulating current after the OFF flows are combined to be the energization time. In this embodiment, as shown in FIG. 3, the time when the U-phase energization and the V-phase energization are about 5 ms. Therefore, the ON times of the U phase and the V phase are shorter than those at the time of U phase energization and V phase energization, respectively.

  FIG. 4 shows an example of the relationship between the ON time of the U-phase and V-phase upper arms and the DC input voltage (DC voltage) in the inverter circuit in this embodiment.

  As shown in FIG. 4, in this embodiment, in order to suppress the energization amount to the U and V phases to a predetermined amount, for example, about 20 Arms, the ON time is shortened as the DC voltage is increased. ON time is set. Accordingly, the energization amount to the U and V phases is set so that the motor 100 does not rotate, that is, the energization amount that maintains the state before the motor 100 is started. Rotation is suppressed, and vibration, noise, and unintended travel are prevented.

  FIG. 5 shows the energization state of the upper and lower arms of the UVW phase when the U phase and V phase are energized.

  As shown in FIG. 5, when the U-phase is energized, the U-phase upper arm is turned on and then turned off (see FIG. 3), but the VW-phase upper arm is maintained in the OFF state. Further, when the U-phase is energized, the UVW-phase lower arm is maintained in the OFF state, the ON state, and the ON state, respectively (in FIG. 3 described above, the lower arm ON / OFF state is omitted).

  Further, as shown in FIG. 5, when the V-phase is energized, the V-phase upper arm is turned on and then turned off (see FIG. 3), but the U-phase upper arm is maintained in the OFF state. In addition, during the V-phase energization, the UVW-phase lower arm is maintained in the ON state, the OFF state, and the ON state, respectively.

  FIG. 6 is a circuit diagram showing current routes when the U-phase energization shown in FIG. 5 (however, when the U-phase upper arm UH is ON) and when V-phase is energized (however, when the V-phase upper arm VH is ON). is there.

  As shown in FIG. 6, when the U-phase upper arm UH is turned on during the U-phase energization, the V-phase lower arm VL and the W-phase lower arm WL are turned on. Cable, U-phase winding (resistance, inductance), V-phase winding, V-phase power supply cable, path following V-phase lower arm VL, U-phase upper arm UH, U-phase power supply cable, U-phase Current (iu, iv, iw) flows through a path that sequentially follows the winding, the W-phase winding, the W-phase power feeding cable, and the W-phase lower arm WL. When the U-phase upper arm UH is turned OFF, the current flows from the U-phase upper arm UH to the U-phase lower arm UL (freewheeling diode) and flows while being attenuated by the energy stored in the winding inductance. to continue.

  Further, as shown in FIG. 6, when the V-phase upper arm VH is turned on during the V-phase energization, the U-phase lower arm UL and the W-phase lower arm WL are turned on. Phase feeding cable, V phase winding, U phase winding, U phase feeding cable, path following U phase lower arm UL, V phase upper arm VH, V phase feeding cable, V phase winding, Current (iu, iv, iw) flows through a path that sequentially follows the W-phase winding, the W-phase power feeding cable, and the W-phase lower arm WL. When the V-phase upper arm UH is turned off, the current is commutated from the V-phase upper arm VH to the V-phase lower arm VL (freewheeling diode) and flows while being attenuated by the energy accumulated in the winding inductance. to continue.

  Here, when one or more of the UVW phases are disconnected between the inverter circuit and the motor and an open state occurs, one or more of the current paths as described above are disconnected. A phase in which no current flows is generated. As will be described later and as can be seen from FIG. 6, the phase in which the current flows and the phase in which the current does not flow differ depending on the disconnection state and whether the current is U-phase energization or V-phase energization. For this reason, the count value of the counter for the OK flag in FIG. 2 (step S1004) is different in each phase, so that the disconnection state can be diagnosed as in step S1007 in FIG.

  FIG. 7 shows an example of the waveform of the UVW phase current during the U-phase energization and the V-phase energization at the timing shown in FIG.

  As shown in FIG. 7, each UVW-phase current (the U-phase current is positive, during the ON time of the U-phase upper arm UH (for example, 100 μs) after the U-phase upper arm UH is turned OFF, is turned on. The absolute value of the VW phase current is negative) rises sharply and increases to the peak value. After the U-phase upper arm UH is turned off, each UVW-phase current continues to flow while being attenuated.

  Here, the positive current is a current that flows from the inverter circuit toward the motor. The negative current is a current that flows from the motor toward the inverter circuit.

  Further, as shown in FIG. 7, the U-phase energization is switched to the V-phase energization 5 ms after the U-phase upper arm UH is turned on. At this time, each UVW-phase current (V-phase current is positive and UW-phase current is positive until the V-phase upper arm VH is turned off after the V-phase upper arm VH is turned on, that is, during the ON time of the V-phase upper arm VH (eg, 100 μs). The absolute value of (negative) rises steeply and increases to the peak value. After the U-phase upper arm UH is turned off, each UVW-phase current continues to flow while being attenuated.

  As shown in FIG. 7, the U-phase energization, the W-phase energization, and the current detection at each energization are executed continuously in time, so that the time required for the disconnection diagnosis can be shortened. For example, according to the study of the present inventor, the total energization time can be within 20 ms, and therefore the disconnection diagnosis time can be within 20 ms. As described above, according to the present embodiment, the disconnection diagnosis can be performed in a short time, so that the disconnection diagnosis can be performed without causing the driver to feel a delay before the vehicle starts running after the vehicle is started. .

  FIG. 8 shows the relationship between the diagnosis result of the disconnection state shown in FIG. 2 (step S1007) and the current of each phase when the UV phase is energized. The notations “X” and “Y” in the figure indicate that current is flowing. The notation “0” indicates that no current flows. “X” indicates a current value (for example, about 20 Arms) corresponding to the setting of the ON time shown in FIG. 2 (step S1002) and FIG. “Y” indicates a predetermined current value equal to or less than X.

  As shown in FIG. 8, the seven disconnection states (Case 1-7 including “No disconnect” (No Open)) are the diagnosis results of the disconnection state shown in FIG. "U phase open" (U phase only disconnected), "V phase open" (V phase only disconnected), "W phase open" (W phase only disconnected), "2,3 phase open" (2 of UVW phases) Phase or three phases (all phases are broken).

  For example, in FIG. 8, when the U phase is disconnected (Case 2, 5, 6), if only the U phase is energized (U phase H side), the current of each UVW phase is “0”. Therefore, “U-phase disconnection” (Case 2) and “2-phase or 3-phase disconnection” (Case 5, 6) cannot be distinguished. On the other hand, if V-phase energization (V-phase H side) is further performed, as can be seen from FIG. 8, “U-phase disconnection” (Case 2) and “2-phase or 3-phase disconnection” (Case 5, 6 ), The flow of each current in the UVW phase is different. Thus, by executing both the U-phase energization and the V-phase energization, it is possible to distinguish between “U-phase disconnection” and “2-phase or 3-phase disconnection”. Similarly, “V-phase disconnection” and “W-phase disconnection” can be similarly identified as “two-phase or three-phase disconnection”.

  Thus, the flow of each current in the UVW phase differs between the case where only one phase of the UVW phase is disconnected and the case of 2 or 3 phase disconnection. Accordingly, since the count value of the OK flag counter in FIG. 2 (step S1004) differs in each phase, the disconnection diagnosis can be performed by the processing in FIG.

  In FIG. 8, when “UW phase disconnection” (Case 6) is V-phase energization (V phase H side) and “VW phase disconnection” (Case 7) is U phase energization (U phase H side), energization Current (X) flows in the phase, and no current flows in the other two phases. This is because a current flows between the winding of the motor 100 and a virtual ground point (virtual neutral point) (not shown) via a stray capacitance in the motor (see FIG. 10 (Case 7 described later)). The same applies to). Therefore, in this embodiment, Case 1, 2, 3, 4, 5, 6 and 7 in FIG. 8 can be identified by executing U-phase energization and V-phase energization.

  In this embodiment, the current at the U-phase energization and the V-phase energization is detected, but not limited to this, the U-phase energization and the W-phase energization, or the V-phase energization and the W-phase energization The current at the time may be detected. The current of each phase may be detected by a current sensor provided for each phase, or a current sensor is provided for two of the UVW phases, and the remaining one is calculated by calculation from the detected current values of the two phases. A phase current value may be calculated.

  Further, in this embodiment, as shown in FIG. 5, the U-phase upper arm and the V-phase upper arm are turned on / off at the time of U-phase energization and V-phase energization, respectively. The V-phase lower arm may be turned ON / OFF. However, according to the ON / OFF state of FIG. 5, when the U-phase lower arm is ON / OFF, the VW-phase upper arm is ON, and when the V-phase lower arm is ON / OFF, the UW-phase upper arm is ON. Such a point is not limited to the UV phase energization, but also applies to the UW phase energization and the VW phase energization.

  As described above, according to the motor control device of the first embodiment, the disconnection between the motor and the inverter circuit is performed while suppressing the energization amount using the current sensor that is installed between the motor and the inverter circuit and is used for the motor control. Can be detected.

  Further, since only two of the three phases are energized and further energized continuously in time, the time required for the disconnection diagnosis can be shortened.

  Also, as shown in FIG. 2, in one disconnection diagnosis period, the current is detected a plurality of times, the number of times the current value exceeds a predetermined threshold is counted, and the disconnection state is diagnosed based on this number of times, Misdiagnosis caused by erroneous detection due to noise or the like is prevented. Therefore, the accuracy of diagnosis is improved.

  FIG. 9 shows an example of ON timing and ON time of the energized phase at the time of disconnection diagnosis in the motor control apparatus that is Embodiment 2 of the present invention.

  In the second embodiment, as shown in FIG. 9, the energization by the inverter circuit is only the U-phase energization unlike the first embodiment (FIG. 3).

  In the second embodiment, the configuration of the motor control device, the processing operation of the control device in disconnection detection, the relationship between the ON time of the U-phase upper arm during U-phase energization and the DC input voltage in the inverter circuit, U-phase energization The current state of the upper and lower arms of the UVW phase at the time, the current route at the time of the U-phase current, and the waveform of the UVW-phase current at the time of the U-phase current are shown in FIG. 1, FIG. 2, FIG. , FIG. 6 and FIG. 7 are almost the same.

  Hereinafter, differences from the first embodiment will be described.

  As shown in FIG. 9, the U-phase is turned on at Timing = 0 [ms], kept on at an ON time of 0.1 ms (100 μs), and then turned off. The U-phase ON period is an ON period of the U-phase upper arm semiconductor switching element, that is, a period during which an ON signal is applied to the control terminal of the semiconductor switching element (in this embodiment, the gate terminal of the IGBT).

  Note that the V phase and the W phase are not turned ON. That is, the semiconductor switching element of the upper arm of the V phase and the W phase is not turned on (refer to FIG. 5 for the lower arm).

  FIG. 10 shows the current of each phase when the U-phase is energized in the second embodiment.

  As shown in FIG. 10, also in the second embodiment, the disconnection state can be diagnosed similarly to the first embodiment. For diagnosis of disconnection status, “No error” (Case 1), “V-phase disconnection” (Case 3), “W-phase disconnection” (Case 4), “U-phase disconnection, or 2 or 3 phase” "Disconnection" (Case 2, 5-7) can be identified.

  Instead of energizing only the U phase, energizing only the V phase or energizing only the W phase may be performed.

  In the second embodiment, when only the U phase is energized, the upper arm of the U phase is turned on for a predetermined ON time (the lower arm turns on the VW phase). The lower arm may be turned on for a predetermined ON time (the upper arm turns on the VW phase). The same applies to energization of only the V phase or energization of only the W phase.

  As described above, according to the motor control device of the second embodiment, as in the first embodiment, the current sensor used for motor control is used to detect disconnection between the motor and the inverter circuit while suppressing the energization amount. it can. In addition, since only one of the three phases is energized, the time required for the disconnection diagnosis can be shortened. Similarly to the first embodiment, in one disconnection diagnosis period, the current is detected a plurality of times, the number of times the current value exceeds a predetermined threshold is counted, and the disconnection state is diagnosed based on this number of times. Misdiagnosis caused by erroneous detection due to the above is prevented. Therefore, the accuracy of diagnosis is improved.

  In addition, this invention is not limited to the Example mentioned above, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  For example, the control lines and signal lines in the figure are those that are considered necessary for the explanation, and not all control lines and signal lines on the product are necessarily shown.

100: motor 200: inverter circuit 300: AC power supply cable 400: battery 500: DC power supply cable 600: control device 700: current sensor 800: smoothing capacitor

Claims (5)

An inverter circuit for driving a three-phase AC motor;
A control device for controlling the inverter circuit;
In a motor control device comprising:
The controller is
While turning on one arm of the high voltage side and the low voltage side in the second phase and the third phase,
The other arm of the high voltage side and the low voltage side in the first phase is turned on for a predetermined time,
Detecting a first current value of a current flowing through the three-phase AC motor;
A motor control device that diagnoses a disconnection state between the three-phase AC motor and the inverter circuit based on the first current value. An inverter circuit for driving a three-phase AC motor;
A control device for controlling the inverter circuit;
In a motor control device comprising:
The controller is
While one arm on the high voltage side and the low voltage side in the second phase and the third phase is turned on, the other arm on the high voltage side and the low voltage side in the first phase is turned on for a predetermined time. And detecting a first current value of the current flowing through the three-phase AC motor,
further,
The other of the high voltage side and the low voltage side in the second phase is turned on while the one arm of the high voltage side and the low voltage side in the first phase and the third phase is turned on. Is turned on only for the predetermined time, and a second current value of the current flowing through the three-phase AC motor is detected,
A motor control device that diagnoses a disconnection state between the three-phase AC motor and the inverter circuit based on the first current value and the second current value. In the motor control device according to claim 1 or 2,
The motor control device according to claim 1, wherein the predetermined time is set according to a DC input voltage of the inverter circuit so that the three-phase AC motor does not rotate. In the motor control device according to claim 1 or 2,
The said control apparatus diagnoses the said disconnection state before starting of the said three-phase alternating current motor, The motor control apparatus characterized by the above-mentioned. In the motor control device according to claim 1 or 2,
The controller is
A motor control device that counts the number of times that the absolute value of the first current value exceeds a predetermined threshold and diagnoses the disconnection state based on the counted number of times.

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