JP2015195644A - Controller of brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a controller of brushless motor capable of reducing the time required for failure detection on a brushless motor while reducing the size and the cost for the detection circuit in failure detection means of the brushless motor.SOLUTION: A controller 10 of a brushless motor 12 is constituted of: a voltage detection circuit 5 which is connected to a winding terminal A of an armature coil 6u which is one of three phases of the brushless motor 12 to detect a voltage Vu generated on the winding terminal A; and a failure detection means (control unit) 1 that detects a failure if the voltage Vu on the winding terminal A is smaller than a threshold value when the power is supplied to the armature coils 6v, 6w of the phases to which the voltage detection circuit 5 is not connected.

Description

  The present invention relates to a brushless motor control device provided with failure detection means for detecting a failure (abnormality) in a coil or harness of a brushless motor.

  Brushless motors are used in a variety of industrial equipment. Especially in automobiles, if a brushless motor breaks down, it has various operational effects such as engine stoppage. It is necessary to notify.

  For this reason, as a conventional failure detection method for a brushless motor, for example, the electric motor drive device of Patent Document 1 includes a monitor that detects the voltage of each line of the power supply line, and the output circuit outputs only to one arbitrary line of the power supply line. Is detected, or when no output is generated, the voltage of each power supply line detected by the monitor is compared with a plurality of preset voltage settings to detect a power supply line abnormality.

  Further, in the brushless motor driving device of Patent Document 2, after all the switching elements in the drive circuit connected to each motor terminal of the brushless motor are turned off, a voltage is applied to one of the motor terminals, By taking in the terminal voltage of each motor terminal from the terminal voltage detection means, failure diagnosis is performed to detect abnormality (disconnection / short circuit) of the motor side circuit.

Japanese Patent Application No. 2006-50707 JP 2008-199852 A

  Especially in the automobile industry, the user's desire to start immediately after turning on the key switch is strong, so it is possible to determine the failure and quickly drive the brushless motor to start the vehicle if normal. It needs to be in a state. Further, in order to improve fuel economy and drivability, weight reduction and downsizing are important issues, and cost reduction is also required. However, in the failure detection of the conventional brushless motor, a voltage monitor circuit for voltage detection is provided at each terminal of the motor, and the drive driver of each phase is driven in order before starting the motor and the failure detection is performed. Since the time for operating the drive circuit for detecting the failure and the voltage monitor circuit are required for the detection circuit, there is a problem that the drive circuit of the brushless motor is hindered from being reduced in size and cost.

  The present invention has been made to solve the above-described problems. In the failure detection means of the brushless motor, the failure detection time is shortened, and at the same time, the detection circuit scale and the component cost are reduced. It is an object.

  In order to solve the above problems, a brushless motor control device according to the present invention is connected to a winding terminal of one of the three phases of a brushless motor and a voltage generated at the winding terminal. And a failure detection means for detecting a failure if the voltage at the winding terminal is less than a threshold when energizing the armature winding of the phase to which the voltage detection means is not connected. It is characterized by this.

  According to the brushless motor control device of the present invention, it is possible to reliably detect the failure of the brushless motor and to greatly reduce the failure detection circuit. There is an effect that it is possible to reduce.

1 is an overall circuit configuration diagram of a brushless motor control system to which a brushless motor control device according to Embodiment 1 is applied. FIG. 3 is a diagram showing an energization pattern of a brushless motor drive circuit in the first embodiment. FIG. 3 is a flowchart showing a failure detection processing process for a brushless motor in the first embodiment. It is a flowchart which shows the failure detection process process before the motor starting in FIG. It is a flowchart which shows the failure detection process process during the motor starting in FIG. It is a flowchart which shows the failure detection process process in the motor normal drive in FIG.

  Hereinafter, a brushless motor control device according to an embodiment of the present invention will be described with reference to FIGS.

Embodiment 1 FIG.
FIG. 1 is an overall circuit configuration diagram of a brushless motor control system to which the brushless motor control device according to the first embodiment is applied, and FIG. 2 shows an energization pattern of the brushless motor drive circuit according to the first embodiment. FIG. FIGS. 3 to 6 are flowcharts showing the failure detection processing steps of the brushless motor in the first embodiment.

  First, an overall circuit configuration of a brushless motor control system to which the brushless motor control device according to the first embodiment is applied will be described with reference to FIG. The brushless motor control device 10 includes a control unit 1, a drive circuit 2 that outputs a drive output to each phase winding terminal of the brushless motor 12 according to an output command of the control unit 1, a U phase, a V phase, and a W of the brushless motor 12. The comparison unit 3 that compares the voltages Vu, Vv, and Vw of the phase winding terminals A, B, and C with the reference voltage V1, the reference voltage generation circuit 4 that generates the reference voltage V1, and the U-phase of the brushless motor 12 The voltage detection circuit 5 detects the voltage Vu of the winding terminal A, and controls the brushless motor 12. Here, the brushless motor 12 includes a stator 6 and a rotor 7. The stator 6 includes three-phase U-phase, V-phase, and W-phase armature windings 6u, 6v, and 6w. It has an N-pole rotor magnetic pole and an S-pole rotor magnetic pole. Here, the voltage detection means is the voltage detection circuit 5, and the failure detection means is a part of the function of the control unit 1.

  Next, the details of each of the circuits constituting the brushless motor control device 10 will be described.

  The control unit 1 includes a latch circuit, a main control circuit, a latch timing signal generation circuit, a voltage command signal generation circuit, and a PWM signal generation circuit. The control unit 1 determines whether or not the driving condition of the brushless motor 12 is satisfied based on the comparison signal of each phase input from the comparison unit 3 described later, and when the driving condition is satisfied Then, semiconductor switching elements Tr6 to Tr11 of the drive circuit 2 described later are turned on / off according to an energization pattern described later. These semiconductor switching elements Tr6 to Tr11 are composed of transistors, and are referred to as transistors in the following description.

  The drive circuit 2 is configured by a three-phase power conversion circuit as a three-phase inverter or a three-phase converter, and includes a U-phase upper arm transistor Tr6, a U-phase lower arm transistor Tr9, and a V-phase upper arm. It comprises a transistor Tr7 that constitutes, a transistor Tr10 that constitutes the lower arm of the V phase, a transistor Tr8 that constitutes the upper arm of the W phase, and a transistor Tr11 that constitutes the lower arm of the W phase. One end of the upper arm of each phase serving as the positive terminal of the drive circuit 2 is connected to the positive terminal of the battery VE as a DC power source, and one end of the lower arm of each phase serving as the negative terminal is the negative side of the battery VE. Connected to the terminal. The connection between the upper arm of each phase of the drive circuit 2 and the lower arm of each phase serves as the AC side terminal of each phase of the drive circuit 2, and each armature winding 6u, 6v, It is connected to 6w winding terminals A, B and C.

  The comparison unit 3 has three comparators 3u, 3v, and 3w, and the respective first input terminals have winding terminals A and B of the respective phases of the brushless motor 12 via resistors R3, R4, and R5. , C and terminal voltages Vu, Vv, and Vw are input, and a reference voltage V1 is input to the second input terminal. These are compared, and a comparison signal is output based on the comparison result. .

  The reference voltage generation circuit 4 includes voltage dividing resistors R1 and R2 connected in series between the positive terminal and the negative terminal of the battery VE. The reference voltage generation circuit 4 includes the first and second comparators 3u, 3v, and 3w of the comparison unit 3. The reference voltage V1 is supplied by being collectively connected to the two input terminals.

  The voltage detection circuit 5 includes resistors R7 and R8 that divide the voltage of the power supply (5V), and a resistor R6 that is connected in series with the voltage dividing point and the winding terminal A. The terminal voltage Vu at the winding terminal A of the brushless motor 12 is measured, and the voltage divided by the resistors R7 and R8 is input to the control unit 1 and used as a detected voltage value for failure detection determination. Here, the voltage divided by the resistors R7 and R8, and the combined resistance of the resistance values of the armature windings 6u, 6v, and 6w of each phase of the brushless motor 12 according to the operation state of the transistors Tr6 to Tr11 of the drive circuit 2; Thus, a change in the voltage of the terminal voltage Vu can be detected.

  Next, a brushless motor control method and control apparatus according to Embodiment 1 of the present invention will be described. FIG. 2 is a diagram showing energization patterns output from the drive circuit 2 to each phase of the brushless motor. In FIG. 2, the U-phase upper arm transistor Tr6, the U-phase lower arm transistor Tr9, the V-phase upper arm transistor Tr7, the V-phase lower arm transistor Tr10, and the W-phase upper arm transistor Tr8. And the time transition of each ON / OFF of transistor Tr11 of the lower arm of W phase is shown. In the waveforms of the transistors Tr6 to Tr11, the on state of the transistor is indicated by a high level (Hi), and the off state of the transistor is indicated by a low level (Low). The energization patterns 1 to 6 will be described below.

  In the energization pattern 1, the U-phase upper arm transistor Tr6 and the V-phase lower arm Tr10 are turned on, and the other transistors are all turned off. Therefore, in this energization pattern 1, the DC current from the positive terminal of the battery VE is such that the U-phase upper arm transistor Tr6, the U-phase armature winding 6u, the V-phase armature winding 6v, and the V-phase The circuit flows to the transistor Tr10 of the lower arm and the negative terminal of the battery VE.

  In the energization pattern 2, the U-phase upper arm transistor Tr6 and the W-phase lower arm Tr11 are turned on, and all other transistors are turned off. Therefore, in this energization pattern 2, the DC current from the positive terminal of the battery VE is such that the U-phase upper arm transistor Tr6, the U-phase armature winding 6u, the W-phase armature winding 6w, and the W-phase The circuit flows to the transistor Tr11 of the lower arm and the negative terminal of the battery VE.

  In the energization pattern 3, the V-phase upper arm transistor Tr7 and the W-phase lower arm Tr11 are turned on, and all other transistors are turned off. Therefore, in this energization pattern 3, the DC current from the positive terminal of the battery VE is such that the V-phase upper arm transistor Tr7, the V-phase armature winding 6v, the W-phase armature winding 6w, and the W-phase armature winding 6 The circuit flows to the transistor Tr11 of the lower arm and the negative terminal of the battery VE.

  In the energization pattern 4, the V-phase upper arm transistor Tr7 and the U-phase lower arm Tr9 are turned on, and all other transistors are turned off. Therefore, in this energization pattern 4, the DC current from the positive terminal of the battery VE is such that the V-phase upper arm transistor Tr7, the V-phase armature winding 6v, the U-phase armature winding 6u, The circuit flows to the transistor Tr9 of the lower arm and the negative terminal of the battery VE.

  In the energization pattern 5, the W-phase upper arm transistor Tr8 and the U-phase lower arm Tr9 are turned on, and all other transistors are turned off. Therefore, in this energization pattern 5, the DC current from the positive terminal of the battery VE is such that the W-phase upper arm transistor Tr8, the W-phase armature winding 6w, the U-phase armature winding 6u, and the U-phase The circuit flows to the transistor Tr9 of the lower arm and the negative terminal of the battery VE.

  In the energization pattern 6, the W-phase upper arm transistor Tr8 and the V-phase lower arm Tr10 are turned on, and all other transistors are turned off. Therefore, in this energization pattern 6, the DC current from the positive terminal of the battery VE is such that the W-phase upper arm transistor Tr8, the W-phase armature winding 6w, the V-phase armature winding 6v, and the V-phase The circuit flows to the transistor Tr10 of the lower arm and the negative terminal of the battery VE.

  The control unit 1 controls on / off of the transistors Tr6 to Tr11 so that the armature windings 6u, 6v, and 6w are energized in the order of the energization patterns 1 to 6. The energization amount to the armature windings 6u, 6v, and 6w is performed by adjusting the on period and the off period of the transistors Tr6 to Tr11 by the PWM control signal from the control unit 1.

  When the brushless motor 12 is driven, the armature current is supplied from the drive circuit 2 to the armature windings 6u, 6v, 6w of each phase of the brushless motor 12 in the order of the energization patterns 1 to 6, thereby the stator 6 A rotating magnetic field is generated. The rotor 7 rotates in synchronization with the rotation of the rotating magnetic field generated by the stator 6.

ここで、Ｈｉは５Ｖ以上、分圧抵抗比率は、Ｒ６：Ｒ７：Ｒ８＝２：１：２の場合である。 Table 1 shows the relationship between the energization patterns 1 to 6 and the failure location of the brushless motor 12 in the voltage Vu of the U-phase winding terminal A.

Here, Hi is 5 V or more, and the voltage dividing resistance ratio is R6: R7: R8 = 2: 1: 2.

  When the brushless motor 12 is normal, when the energization patterns 1 to 6 are energized, the detected voltage Vu is the voltage of the battery VE that is a partial pressure of the armature winding 6v and the armature winding 6w. Therefore, a normal state shown in Table 1 is obtained.

  On the other hand, when a harness abnormality (disconnection) occurs between the winding terminal A of the brushless motor 12 and the armature winding 6u, the state indicated by the U-phase disconnection in Table 1 is obtained. Further, when the armature winding 6u is disconnected, the result shown in the state of the U-phase disconnection in Table 1 is obtained.

  In the energization pattern 3, when the U-phase armature winding 6u is disconnected, the voltage Vu detected at the winding terminal A is a value determined by the resistance voltage dividing ratio of the resistors R7 and R8.

  Further, in the energization pattern 3, when the V-phase armature winding 6v is disconnected, the voltage Vu detected at the winding terminal A is grounded through the W-phase armature winding 6w, so that the resistor R6 is grounded. The voltage dividing ratio between the combined resistance value of the resistor R6 and the resistor R8 and the resistor R7 is the state indicated by the V-phase disconnection in Table 1.

  In addition, in the energization pattern 3, the voltage Vu detected when the W-phase armature winding 6w is disconnected is connected to the battery VE through the W-phase armature winding 6w. It will be in the state shown by the phase break. The resistance values of the resistors R6, R7, and R8 are set to resistance values that can ignore the resistance values of the armature windings 6u, 6v, and 6w.

  Next, the failure detection processing method will be described with reference to the flowchart of the brushless motor failure detection processing step of FIG. Here, it is assumed that the failure determination threshold value based on the voltage Vu of the winding terminal A is 4V. First, in step S01, the control unit is initialized. Subsequently, in step S02, a failure detection process before starting the motor is performed. Details of the processing are shown in the failure detection processing step before starting the motor in FIG. If the process of FIG. 4 is complete | finished, a motor starting process (forced commutation) will be performed by step S03. Subsequently, in step S04, failure detection processing during motor activation is performed. The details of the processing are shown in the failure detection processing step during motor activation in FIG. If the process of FIG. 5 is complete | finished, a motor normal drive process will be performed by step S05. Thereafter, in step S06, failure detection processing during normal motor driving is performed. Details of the processing are shown in the failure detection processing step during normal motor driving in FIG. When the process of FIG. 6 is finished, a series of failure detection process steps are finished. As shown in FIG. 3, detection is performed in each state before starting the brushless motor 12, during starting (forced commutation), and during normal driving. Failure detection may be performed only in each state or in combination.

  There are six energization patterns of the brushless motor 12, but in the present invention, as energization patterns used for motor failure detection, as shown in Table 1, there are only two energization patterns. Can be determined. Here, since the voltage detection circuit 5 detects the voltage Vu of the U-phase winding terminal A, only the voltage detected when the energization patterns 3 and 6 are energized is measured. A failure (abnormality) can be detected.

  The failure detection processing step before starting the motor shown in FIG. 4 will be described. In the failure detection process before starting the motor, the failure can be detected by performing only two energization patterns on the armature winding of the brushless motor 12. First, in step S11, the energization pattern 3 is energized. In step S12, the voltage detected by the energization pattern 3 is measured, and the value is set to a. Subsequently, in step S13, the energization pattern 6 is energized. In step S14, the voltage detected by the energization pattern 6 is measured, and the value is set to b. Next, when the voltage detection with these two energization patterns is completed, the values of a and b are determined in step S15. If a <4V or b <4V, there is a failure. It moves to step S16 and performs the process at the time of failure occurrence. After this process is completed, the flow returns to the flow of the failure detection process step in FIG. If a ≧ 4V and b ≧ in step S15, it is determined that there is no failure, and the flow returns to the flow of the failure detection processing step in FIG. Here, the presence / absence of a failure is determined when the values of a and b are obtained. However, the determination may be performed for each measurement in each energization pattern. Since a failure can be determined only with two energization patterns, a failure (abnormality) can be determined in a short time.

  The motor startup failure detection process shown in FIG. 5 will be described. In the failure detection process during motor activation, when the motor is activated (forced commutation), the failure can be determined in a short time by starting from an energization pattern that allows failure detection. FIG. 5 shows an example when starting from the energization pattern 3. A failure can be detected with four energization patterns with respect to all six energization patterns. First, in step S21, the energization pattern 3 is energized. In step S22, the voltage detected by the energization pattern 3 is measured, and the value is set to a. In steps S23 and S24, the energization patterns 4 and 5 are energized. Subsequently, in step S25, the energization pattern 6 is energized. In step S26, the voltage detected by the energization pattern 6 is measured, and the value is set to b. Next, when the voltage detection with these two energization patterns is completed, the values of a and b are determined in step S27. If a ≧ 4V and b ≧, there is no failure. In step S28 and S29, the energization patterns 1 and 2 are energized. Thereafter, in step S31, it is determined whether or not the activation process is completed. If the activation is completed, the process returns to the flow of the failure detection process step in FIG. If the startup is not completed, the process returns to step S21, and the failure detection process during motor startup is continued. On the other hand, if a <4V or b <4V in step S27, it is determined that there is a failure, the process moves to step S30, and a failure occurrence process is performed. After this process is completed, the flow returns to the flow of the failure detection process step in FIG. The determination of failure detection is performed by measuring a voltage with an energization pattern capable of detecting a failure, as in the case of the stop.

  The motor normal drive failure detection processing step shown in FIG. 6 will be described. The failure detection process of normal motor drive is the same as the concept of failure detection before startup and during startup. However, in normal driving, the energization pattern changes from 1 to 6 in synchronism with the rotational speed of the motor, so that it is not possible to control a reduction in time for detecting a failure. However, if the start of detection coincides with the timing of performing the failure determination from the energization pattern 3 or the energization pattern 6, the failure detection time is shortened. Steps S41 to S50 are the same as steps S21 to S30 in the motor activation failure detection processing step of FIG. In step S51, it is determined whether or not the normal driving of the motor is to be ended. When the normal driving is to be ended, the flow returns to the flow of the failure detection processing step in FIG. If the normal drive is not terminated, the process returns to step S41, and the motor normal drive failure detection process is continued.

  By setting the threshold for determining the failure of the detected voltage in two stages, the location of the failure can be determined in more detail. For example, when the threshold value of the first stage is set to 2.9 V and the threshold value of the second stage is set to 4 V, the condition that the detected voltage is less than the first stage threshold and the second stage threshold in the energization pattern 3 Is satisfied, the V-phase armature winding 6v is disconnected, and if the energization pattern 6 satisfies the conditions of less than the first threshold and less than the second threshold, the W phase If the armature winding 6w is disconnected and the condition below the first-stage threshold is satisfied and the condition below the second-stage threshold is not satisfied, the U-phase armature winding 6u is disconnected, or It can be determined that this is a complex failure. However, Table 1 shows an example of a composite failure such as a UV phase disconnection, but it is assumed that a plurality of failures are unlikely to occur at the beginning of the failure. The most likely combination failure is forgetting to connect the winding terminals A, B, and C (in the case of a single connector with the winding terminals A, B, and C integrated). As a result, the failure part can be specified in general, and the repair time can be shortened.

In the above description, the detection circuit 5 is connected to the U-phase winding terminal A. However, the detection circuit 5 may be connected to the V-phase winding terminal B. In this case, it is possible to detect a failure by using only the voltage detected when the energization patterns 2 and 5 are energized for the determination. Table 2 shows the relationship between the energization patterns 1 to 6 and the failure location of the brushless motor 12 at the voltage Vv of the V-phase winding terminal B. Even in this case, the failure detection processing steps of the brushless motor of FIGS. 3 to 6 can be similarly applied by changing the energization pattern to 2 and 5.

Alternatively, the detection circuit 5 may be connected to the W-phase winding terminal C. In this case, only the voltage detected when the energization patterns 1 and 4 are energized is used for the determination. Thus, it is possible to detect a failure. Table 3 shows the relationship between the energization patterns 1 to 6 and the failure location of the brushless motor 12 in the voltage Vw of the W-phase winding terminal C. Even in this case, the failure detection processing steps of the brushless motor shown in FIGS. 3 to 6 can be similarly applied by changing the energization pattern to 1 and 4.

  Thus, according to the brushless motor control apparatus according to the first embodiment, the voltage detection circuit that detects the voltage generated at the winding terminal of one of the three armature windings of the brushless motor is provided. The detection circuit scale is reduced at the same time as reducing the failure detection time by detecting a failure if the voltage at the winding terminal is below the threshold when the armature winding of the phase to which the detection circuit is not connected is energized There is an effect that it is possible to reduce the cost and the parts cost.

  Note that the present invention is not limited to the above-described embodiment, and the embodiment can be appropriately modified and omitted within the scope of the invention.

  DESCRIPTION OF SYMBOLS 1 Control unit, 2 Drive circuit, 3 Comparison unit, 4 Reference voltage generation circuit, 5 Voltage detection circuit, 6 Stator, 6u, 6v, 6w Armature winding, 7 Rotor, 10 Brushless motor control apparatus, 12 Brushless motor, A, B, C Winding terminals, R1-R8 resistors, Tr6-Tr11 transistors, VE battery.

In order to solve the above problems, a brushless motor control device according to the present invention is connected to a winding terminal of one of the three phases of a brushless motor and a voltage generated at the winding terminal. voltage detecting means for detecting, with the voltage of the winding terminals of the two energization pattern when energization of the armature winding of the phase to which the voltage detecting unit is not connected to detect a fault if it is less than the threshold value, the winding Failure detecting means for identifying an armature winding that has failed due to the voltage of the wire terminal .

In order to solve the above problems, a brushless motor control device according to the present invention is connected to a winding terminal of one of the three phases of a brushless motor and a voltage generated at the winding terminal. voltage detecting means for detecting, malfunction voltage winding terminals in the two energization pattern when energization of the armature winding of the phase to which the voltage detecting unit is not connected you detected as a failure if it is less than the threshold value And a detecting means.

Claims (4)

Voltage detecting means connected to a winding terminal of one of the three phases of the brushless motor and detecting a voltage generated at the winding terminal;
Failure detection means for detecting a failure if the voltage at the winding terminal is less than a threshold when the armature winding of the phase not connected to the voltage detection means is energized. Control device for brushless motor.   The brushless motor control device according to claim 1, wherein the failure detection is performed before the brushless motor is started.   The brushless motor control device according to claim 1, wherein the failure detection is performed during normal driving of the brushless motor.   The brushless motor control device according to claim 1, wherein the failure detection is performed during forced commutation of the brushless motor.

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