KR101348543B1 - Apparatus and method for detecting winding fault of permanent magnet motor - Google Patents

Abstract

The present invention relates to a winding failure determination device and method of the permanent magnet motor, the winding failure determination device of the permanent magnet motor according to an embodiment of the present invention, a three-phase winding winding wound around the stator, and the three-phase winding winding A permanent magnet motor including an auxiliary winding wound around the stator, a rotor accommodated in the stator to rotate, and the auxiliary winding according to the rotation of the rotor and an input current input to the three-phase main winding. And a voltage detector configured to detect a voltage induced in the controller, and a failure determiner configured to determine a failure of the three-phase main winding using the voltage of the auxiliary winding. Accordingly, the system can be miniaturized and the cost can be reduced by determining the failure of the stator winding of the permanent magnet motor without additional sensors.

Description

Winding failure determination device and method of permanent magnet motor {APPARATUS AND METHOD FOR DETECTING WINDING FAULT OF PERMANENT MAGNET MOTOR}

The present invention relates to a winding failure determining apparatus and method of the permanent magnet motor, and more particularly to a technique for determining the winding failure of the stator of the permanent magnet motor.

Surface-attached and embedded brushless DC motors (BLDC motors) and synchronous motors of permanent magnets are increasingly used in various electric drive systems due to the high power density and high efficiency characteristics of permanent magnets. . In particular, with the increasing number of systems using electric motors as a main driving source, such as many automation systems and electric vehicles, technologies for compensating the reliability of electric motors for minimizing damage occurring when a motor breaks down have been developed. When a motor failure occurs, not only a lot of physical damage but also damage to life can occur. In particular, in a system using an electric motor as an engine of a vehicle such as an electric vehicle, the failure of the motor is directly connected to life. Therefore, there is a great need for diagnosis and prediction of motor failure.

Motor faults can be broadly divided into stator turn faults, power converter faults (power converter faults), and mechanical faults. In addition, in the case of permanent magnet motor, there is a failure caused by the scattering of the magnet of the rotor, demagnetization of the magnet, etc. Among the failures, the most likely failure is an electromagnetic phenomenon such as vibration, overload between terminals, inflow of foreign materials, etc. This is a stator turn fault that gradually breaks the insulation of the windings resulting in a short circuit. Stator winding breakdown failure occurs because heat is generated in the shorted coils, and this heat breaks the insulation of adjacent coils in proportion to the square of the circulating current, resulting in very fast failure of one phase winding. I need a response.

One conventional motor failure detection method compares input parameters such as voltage and current to determine a failure. This method is relatively simple in principle and useful for managing the same and many motors simultaneously, such as industrial motors. However, the cost of the analysis program is expensive, and the analysis energy value has to be updated according to the capacity and type of the motor. Alternatively, the fault determination in the motor for precision control uses the harmonic characteristics of the input current, which is observed by comparing the second harmonic of the q-axis current of the dq frame and comparing the harmonic data when the motor is in a steady state. Determine whether or not. This method allows the controller to perform control and at the same time determine the fault remotely without additional diagnostic equipment, using the full harmonic spectrum of the phase current and requiring learning of normal harmonics. However, the calculation of the failure time should be quick, and it is difficult to determine the phase in which the failure occurred.

In another method, a pattern of input voltages and currents of the motor is collected every time using various sensors, compared with a reference value, and determined to be a failure when it exceeds an error tolerance range. However, this method has the disadvantage of high sensor and system cost. As another method, there is a method of detecting a failure by detecting an insulation state of the stator winding using a PD (PD), which is mainly used in a generator or a high voltage motor. Partial discharge is a method in which a harmonic current pulse is collected by a PD sensor installed in each phase when the electric field exceeds the strength of the insulator, and is discriminated in a system that can be monitored. However, this method is difficult to apply to low voltage motors or small motors.

In addition to this, techniques using wavelet transform and experimental methods based on intelligent control methods are used, but these methods require additional signal processing equipment or measurement equipment, and intelligent control techniques require the extraction of detailed failure characteristics of the diagnostic system. .

The technical problem to be achieved by the present invention is to provide a winding failure determination device and method of the permanent magnet motor to determine the failure of the stator winding of the permanent magnet motor without additional sensors, and accurately determine the phase of the stator in which the failure occurs It is for.

Winding failure determination device of a permanent magnet motor according to an embodiment of the present invention, the three-phase winding winding wound on the stator, the auxiliary winding wound on the stator corresponding to the three-phase winding winding, and is accommodated in the stator to rotate A permanent magnet motor including a rotor, a voltage detector for detecting a voltage induced in the auxiliary winding according to the rotation of the rotor and an input current input to the three-phase main winding, and a voltage of the auxiliary winding It includes a failure determination unit for determining the failure of the three-phase main winding.

The auxiliary winding may have a smaller number of turns than the three-phase main winding and may be connected to an external resistance having a larger internal resistance than the three-phase main winding.

The auxiliary winding may be formed in parallel with respect to each of the three-phase main windings.

The failure determining unit may determine whether a reverse magnetic field phenomenon or a magnetic saturation phenomenon of the auxiliary winding occurs.

According to another aspect of the present invention, there is provided a method of determining a winding failure of a permanent magnet motor, including: adding an auxiliary winding to a stator of a permanent magnet and adding auxiliary windings corresponding to the three phase winding; A voltage detecting step of detecting a voltage induced in the auxiliary winding according to the rotation of the rotor accommodated in the inside of the rotating body and an input current input to the three-phase main winding; and the three phase using the voltage of the auxiliary winding. And a failure determination step of determining a failure of the main winding.

The winding failure determination device and method of the permanent magnet motor according to the present invention can reduce the system size and reduce the system construction cost by determining the failure of the stator winding of the permanent magnet motor without additional sensors. In addition, by accurately determining the phase of the stator where a failure occurs, the failure can be detected quickly at the beginning of the failure, thereby improving the reliability of the motor.

1 is a configuration of the winding failure determination device of a permanent magnet motor according to an embodiment of the present invention,
2 is a flow chart of the winding failure determination method of the permanent magnet motor according to FIG.
Figure 3a is a cross-sectional view of the stator of the permanent magnet winding the three-phase main winding and auxiliary winding according to Figure 1,
3B is an exemplary view for explaining that the three-phase main winding according to FIG. 3A is connected to a Y connection;
4A is an exemplary diagram for describing a self saturation phenomenon determined by the failure determination unit according to FIG. 1;
FIG. 4B is an exemplary diagram for describing a reverse magnetic field phenomenon determined by the failure determination unit of FIG. 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The terms used are terms selected in consideration of the functions in the embodiments, and the meaning of the terms may vary depending on the user, the intention or the precedent of the operator, and the like. Therefore, the meaning of the terms used in the following embodiments is defined according to the definition when specifically defined in this specification, and unless otherwise defined, it should be interpreted in a sense generally recognized by those skilled in the art.

1 is a block diagram of a winding failure determination device of a permanent magnet motor according to an embodiment of the present invention.

Referring to FIG. 1, the winding failure determining apparatus 100 of the permanent magnet motor 110 includes a permanent magnet motor 110, a voltage detector 120, and a failure determiner 130. The permanent magnet motor 110 specifically includes an AC power supply 111, a rectifier 112, an inverter 113, and a voltage induction part 114. When power is output from the AC power source 111, the rectifier 112 rectifies the AC power source 111 and transfers the AC power source 111 to the inverter 113. The inverter 113 supplies the rectified power to the voltage inducing unit 114. The functions of the AC power source 111, the rectifier 112, and the inverter 113 included in the permanent magnet motor 110 are the same as those used for a general motor.

The voltage inducing unit 114 is composed of a stator and a rotor accommodated in the stator to rotate. The stator is composed of a plurality of teeth, and each of the stator teeth is formed with a main winding 115. The main winding 115 is a main winding supplied with input power, and input power is supplied from the inverter 113 to the main winding 115, and electromotive force is generated as the rotor rotates. In this case, the main winding 115 may be connected by a three-phase (A, B, C) Y connection. In the present invention, the sovereign winding 115 is used in the same sense as the three-phase sovereign winding 115.

The winding formed on the stator includes an auxiliary winding 116 in addition to the three-phase main winding 115. The auxiliary winding 116 is a failure detection winding for detecting a failure such as a short circuit to the three-phase main winding 115. The auxiliary winding 116 is not supplied with a separate input current. The auxiliary winding 116 is formed at each tooth of the stator on which the three-phase main winding 115 is formed, and is formed independently of the three-phase main winding 115. For example, when the three-phase main winding 115 is wound around a stator in which nine teeth are formed, nine auxiliary windings 116 are wound around each tooth. In this case, the auxiliary winding 116 may be formed in a direction parallel to the main winding 115 on one tooth. Since the number of turns that can be formed per tooth is limited, the auxiliary winding 116 preferably has fewer turns than the three-phase main winding 115.

In addition, the auxiliary winding 116 may be connected to an external resistor R having a resistance larger than the internal resistance of the three-phase main winding 115. Since the three-phase main winding 115 and the auxiliary winding 116 are formed in the same stator and the internal resistance is proportional to the number of turns, the internal resistance of the auxiliary winding 116 is relatively higher than that of the three-phase main winding 115. More induced current flows through the small auxiliary winding 116. Since the auxiliary winding 116 has fewer windings than the three-phase main winding 115, since the internal resistance is inevitably smaller, more induction current flows in the auxiliary winding 116, thereby improving the efficiency of the permanent magnet motor 110. Reduced. Therefore, an inductive current flowing through the auxiliary winding 116 may be reduced by connecting an external resistance having a resistance value larger than that of the three-phase main winding 115 to the auxiliary winding 116.

The voltage detector 120 detects electromotive forces Ea, Eb, and Ec which are voltages induced in the auxiliary winding 116. The auxiliary winding 116 is formed without being connected to the three-phase main winding 115, and the voltage detector 120 detects an induced voltage for each auxiliary winding 116. For example, in FIG. 1, three auxiliary windings 116 are formed in the stator of the voltage inducing unit 114, and the voltage detection unit 120 is configured to increase or decrease the induced voltage of each of the three auxiliary windings 116. Obtain information about The voltage detector 120 outputs the induced voltage information detected from each auxiliary winding 116 to the failure determination unit 130.

The failure determining unit 130 receives information about the magnitude and the increase / decrease of the induced voltage of the auxiliary winding 116 from the voltage detector 120, and compares it with a reference value for the magnitude and the increase or decrease of the induced voltage in a steady state. do. The failure determining unit 130 compares the information on the induced voltage of each auxiliary winding 116 with a reference value and determines whether the three-phase main winding 115 is broken based on whether or not it is within a preset tolerance range. . In this case, whether or not a failure may be determined based on whether a reverse magnetic field phenomenon or a magnetic saturation phenomenon occurs at the voltage of the auxiliary winding 116. In this case, the failure determination unit 130 calculates the magnetic flux by integrating the induced voltage of the auxiliary winding 116, and using the calculated magnetic flux, the reverse magnetic field phenomenon and the magnetic saturation phenomenon, which are the failure phenomenon of the three-phase main winding 115 Can be judged. The failure determination unit 130 may determine whether or not a failure occurs for each auxiliary winding 116, and in response to an initial failure by controlling the inverter 113 of the permanent magnet motor 110 when a failure occurs.

In addition, the failure determination unit 130 may determine whether the main winding 115 wound around each phase or each tooth of the three-phase main winding 115. As described above, since the auxiliary winding 116 is formed corresponding to the three-phase main winding 115, if a failure occurs in any one of the main winding 115, the current input to the main winding 115 is cut off, etc. This phenomenon occurs and, unlike the case where the voltage induced in the auxiliary winding 116 is corresponding to the normal state. Therefore, it is possible to prevent an additional motor failure by accurately grasping the failure location of the main winding 115 at an early stage.

In addition, the failure determination unit 130 may display information on whether a failure state on an external display (not shown). For example, if the windings wound on the 3rd, 6th and 9th teeth of the 9 teeth stator are in phase a, the reverse magnetic field is detected at the 6th tooth and the tooth saturation at the 3rd and 9th teeth is detected. If detected, it is determined that a failure has occurred in the a-phase winding wound around the sixth position, and by controlling the inverter 113 of the permanent magnet motor 110, it is possible to quickly respond to the initial failure.

2 is a flowchart illustrating a winding failure determination method of the permanent magnet motor of FIG. 1.

Referring to FIG. 2, a three-phase main winding 115 and a corresponding auxiliary winding 116 are added to the stator of the voltage inducing unit 114 included in the winding failure determination method of the permanent magnet motor 110. As described above, the auxiliary winding 116 is formed in the direction parallel to each three-phase main winding 115, has a smaller number of turns than the main winding 115, and has a resistance larger than the internal resistance of the main winding 115. It can be connected to an external resistor. First, the voltage detector 120 detects a voltage induced in the auxiliary winding 116 according to the rotation of the rotor accommodated in the stator and the input current input to the three-phase main winding 115 (S210). . The voltage detector 120 may detect an induced voltage induced in each auxiliary winding 116 in real time.

Next, the failure determination unit 130 determines the failure of the three-phase main winding 115 by using the voltage of the auxiliary winding 116 input from the voltage detector 120 (S220). In this case, the failure determination unit 130 calculates the magnetic flux by integrating the induced voltage of the auxiliary winding 116, and using the calculated magnetic flux, the reverse magnetic field phenomenon and the magnetic saturation phenomenon, which are the failure phenomenon of the three-phase main winding 115 Can be judged. When the failure determination unit 130 determines the failure of the three-phase main winding 115, by controlling the inverter 113 of the permanent magnet motor 110 to control the operation of the permanent magnet motor 110 to prevent the failure of additional windings It can be prevented.

3A is a cross-sectional view of a stator of a permanent magnet in which a three-phase main winding and an auxiliary winding are wound in accordance with FIG. 1, and FIG. 3B is an exemplary view for explaining that the three-phase winding in accordance with FIG.

Referring to FIG. 3A, for example, the stator may include nine teeth, and three-phase main windings 115 and auxiliary windings 116 may be formed on each tooth. In this case, the three-phase main winding 115 formed on each tooth is connected in the form of a Y connection, the auxiliary winding 116 is formed separately on each tooth. In addition, the main winding 115 corresponding to each phase may be formed over a plurality of teeth. For example, the main winding 115 formed at the A1, A2, and A3 teeth, the main winding 115 formed at the B1, B2, and B3 teeth, and the main winding 115 formed at the C1, C2, and C3 teeth have different images. Have The auxiliary winding 116 is wound in the same direction as the direction in which the three-phase main winding 115 is wound to the teeth. In addition, since the length of each tooth may be limited in design, the number of turns of the auxiliary winding 116 may be wound in a smaller number than the main winding 115. In this case, the coil diameter of the auxiliary winding 116 is smaller than the coil diameter of the main winding 115.

Referring to Figure 3b, it can be seen that the main winding (115) wound on the fault of Figure 3a is connected in the form of a Y connection. The main windings 115 included in each phase may be composed of several main windings 115 according to the number of teeth. In addition, it can be seen that the auxiliary winding 116 is wound around the main winding 115 in the same direction. In this case, as described above, the auxiliary windings 116 or the main windings 115 and the auxiliary windings 116 are not connected to each other but are formed separately from each other.

4A is an exemplary diagram for describing a self saturation phenomenon determined by the failure determination unit 130 according to FIG. 1, and FIG. 4B is a diagram for describing the reverse magnetic field phenomenon determined by the failure determination unit 130 according to FIG. 1. It is an illustration.

In the case of FIG. 4A, it can be seen that the magnitude of the induced voltage does not coincide with the induced voltage of the auxiliary winding 116 compared with the induced voltage in the normal state. This indicates that a self saturation phenomenon occurs in the main winding 115 wound around the teeth on which the auxiliary winding 116 is formed. In the case of FIG. 4B, it can be seen that the voltage induced in the auxiliary winding 116 is different from the induced voltage in comparison with the induced voltage in the normal state. This indicates that an inverse magnetic field phenomenon occurs in the main winding 115 wound around the teeth on which the auxiliary winding 116 is formed. In this case, the failure determining unit 130 may control the inverter 113 of the permanent magnet motor 110 and replace the failed main winding 115. In addition, when a magnetic saturation phenomenon or a reverse magnetic field phenomenon is detected in the auxiliary winding 116, the failure determination unit 130 may indicate a failure of a winding wound around a specific value on an external display or generate a warning sound.

The winding failure determination device and method of the permanent magnet motor according to the present invention can reduce the system size and reduce the system construction cost by determining the failure of the stator winding of the permanent magnet motor without additional sensors. In addition, by accurately determining the phase of the stator where a failure occurs, the failure can be detected quickly at the beginning of the failure, thereby improving the reliability of the motor.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, Therefore, the present invention should be construed as a description of the claims which are intended to cover obvious variations that can be derived from the described embodiments.

100: winding failure determination device 110: permanent magnet motor
111: AC power supply 112: rectifier
113: inverter 114: voltage induction part
115: sovereignty 116: auxiliary sovereignty
120: voltage detection unit 130: failure determination unit

Claims (8)

A permanent magnet motor including a three-phase winding wound around the stator, an auxiliary winding wound around the stator corresponding to the three-phase winding winding, and a rotor accommodated in the stator to rotate;
A voltage detector detecting a voltage induced in the auxiliary winding according to the rotation of the rotor and an input current input to the three-phase main winding; And
Including a failure determination unit for determining the failure of the three-phase main winding using the voltage of the auxiliary winding,
The failure determination unit,
The winding failure determination device of the permanent magnet motor for determining whether the reverse magnetic field phenomenon or the magnetic saturation phenomenon of the auxiliary winding occurs. The method of claim 1, wherein the auxiliary winding,
The winding failure determination device of the permanent magnet motor connected to an external resistance having a smaller number of windings than the three-phase main winding and having a larger internal resistance than the three-phase main winding. The method of claim 1, wherein the auxiliary winding,
Winding failure determination device of the permanent magnet motor is formed in parallel with respect to each of the three-phase main winding. delete In the winding failure determination method of the permanent magnet motor comprising a three-phase winding wound on the stator, an auxiliary winding wound on the stator corresponding to the three-phase winding winding, and a rotor accommodated in the stator to rotate,
A voltage detecting step of detecting a voltage induced in the auxiliary winding according to the rotation of the rotor accommodated and rotating in the stator and the input current input to the three-phase main winding; And
A failure determination step of determining a failure of the three-phase main winding using the voltage of the auxiliary winding;
The failure determination step,
Winding failure determination method of the permanent magnet motor for determining whether the reverse magnetic field phenomenon or the magnetic saturation phenomenon of the auxiliary winding occurs. The method of claim 5, wherein the auxiliary winding,
The winding failure method of the permanent magnet motor connected to an external resistance having a smaller number of windings than the three-phase main winding and a larger internal resistance than the three-phase main winding. The method of claim 5, wherein the auxiliary winding,
The winding fault determination method of the permanent magnet motor is formed in parallel with respect to each of the three-phase main winding. delete

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