A permanent magnet generator fault detection device

Abstract

The present application belongs to the field of aviation power generation system design, and relates to a permanent magnet generator fault detection device. The device includes a short-circuit detection module to the ground, which is used to connect the ripple signal after rectification and voltage division of the three-phase permanent magnet generator to the CPU component through the Zener diode V9; an open circuit and phase-to-phase short circuit detection module, which is used to sample the voltage of each two signals of the three-phase permanent magnet generator and send them to the CPU component; the CPU component is configured to: when a high-level signal is connected through the Zener diode V9, it is determined that the three-phase permanent magnet generator is short-circuited to the ground; when any two DC voltage signals change from high level to low level, it is determined that the phases simultaneously associated with the two DC voltage signals are open; when one DC voltage signal is low level and the levels of the other two DC voltage signals are reduced, it is determined that the two phases corresponding to the low level are short-circuited. The present application can effectively identify various fault types of permanent magnet generators and improve the safety of aviation power generation systems.

Description

Technical Field

[0001] The present application belongs to the field of aviation power generation system design, and specifically relates to a permanent magnet generator fault detection device. Background Art

[0002] As the auxiliary exciter of the three-stage aviation generator, the permanent magnet generator provides power supply to the generator controller on the one hand, and provides excitation to the main exciter of the three-stage generator after rectification inside the generator controller to complete the system power generation function on the other hand. Therefore, it is extremely important to monitor the voltage of the permanent magnet generator to determine the type of permanent magnet generator fault and to complete the related control and protection functions of the auxiliary power generation system and the power supply system. The current generator controller forms a square wave by shaping the output voltage waveform of the permanent magnet generator and sends it to the CPU component for frequency counting, and then completes the over / under frequency protection of the power generation system and the over / under speed protection of the permanent magnet generator through the CPU component and other components, but the detection design of the fault modes such as open circuit and short circuit of the permanent magnet generator has not yet been carried out. Summary of the invention

[0003] In order to solve the above problems, the present application provides a permanent magnet generator fault detection device, which is used to judge the various fault types of the permanent magnet generator, add relevant fault judgment criteria to the power generation system, improve the control and protection function of the power generation system, and intervene in time after judging that the permanent magnet generator has a corresponding fault, so as to avoid serious damage to the permanent magnet generator, the generator controller and even the entire power generation system.

[0004] The permanent magnet generator fault detection device of the present application mainly includes:

[0005] The ground short circuit detection module is used to connect the ripple signal after rectification and voltage division of the three-phase permanent magnet generator to the CPU component through the Zener diode V9;

[0006] The open circuit and interphase short circuit detection module is used to sample the voltage of every two signals of the three-phase permanent magnet generator, obtain three DC voltage signals, and send the three DC voltage signals to the CPU component;

[0007] The CPU components include:

[0008] The first determination unit is used to determine that the three-phase permanent magnet generator is short-circuited to the ground when a high-level signal is connected via the Zener diode V9;

[0009] A second determination unit is used to determine that the phases simultaneously associated with the two DC voltage signals are open when any two DC voltage signals among the three DC voltage signals change from a high level to a low level;

[0010] The third determination unit is used to determine that two phases corresponding to the low level are short-circuited when one of the three DC voltage signals is at a low level and the levels of the other two DC voltage signals are reduced.

[0011] Preferably, the short-circuit-to-ground detection module comprises:

[0012] A full-bridge rectifier circuit is used to rectify the collected three-phase permanent magnet generator signal to generate a pulsating DC voltage signal;

[0013] A voltage divider circuit, used for dividing the pulsating DC voltage signal;

[0014] The AC coupling circuit is used to remove the DC component of the divided pulsating DC voltage signal and obtain the ripple signal of the permanent magnet generator through rectification by diode V7;

[0015] The Zener diode V9 is arranged between the AC coupling circuit and the CPU component. When the signal of the three-phase permanent magnet generator is normal, the ripple signal cannot break through the Zener diode, and the CPU receives a low-level signal. When the three-phase permanent magnet generator is short-circuited to the ground, the ripple signal can break through the Zener diode, and the CPU receives a high-level signal.

[0016] Preferably, an RC filter circuit consisting of a resistor R4 and a capacitor C2 is further provided between the Zener diode V9 and the CPU component.

[0017] Preferably, the breakdown voltage of the Zener diode V9 is 5V.

[0018] Preferably, the open circuit and phase short circuit detection module includes:

[0019] Three isolation transformers are used to sample the phase-to-phase voltage of each two signals of the three-phase permanent magnet generator;

[0020] A voltage-dividing filter circuit is used to perform voltage-dividing filtering on the collected phase-to-phase voltage;

[0021] The peak sampling circuit is used to perform peak sampling on the voltage after voltage division and filtering to obtain three DC voltage signals.

[0022] Preferably, the CPU component further includes:

[0023] The fault processing module is used to output a drive control signal for disconnecting the excitation and main contactor when the three-phase permanent magnet generator is short-circuited to the ground, the phase circuit is open, or the phase circuit is short-circuited.

[0024] This application can effectively identify various fault types of permanent magnet generators and improve the safety of aviation power generation systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of a permanent magnet generator short circuit to ground detection circuit of a preferred embodiment of the permanent magnet generator fault detection device of the present application.

[0026] Figure 2 It is the principle diagram of the permanent magnet generator open circuit and phase short circuit detection circuit. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and cannot be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in combination with the drawings.

[0028] The present application provides a permanent magnet generator fault detection device, which mainly includes:

[0029] The ground short circuit detection module is used to connect the ripple signal after rectification and voltage division of the three-phase permanent magnet generator to the CPU component through the Zener diode V9;

[0030] The open circuit and interphase short circuit detection module is used to sample the voltage of every two signals of the three-phase permanent magnet generator, obtain three DC voltage signals, and send the three DC voltage signals to the CPU component;

[0031] The CPU components include:

[0032] The first determination unit is used to determine that the three-phase permanent magnet generator is short-circuited to the ground when a high-level signal is connected via the Zener diode V9;

[0033] A second determination unit is used to determine that the phases simultaneously associated with the two DC voltage signals are open when any two DC voltage signals among the three DC voltage signals change from a high level to a low level;

[0034] The third determination unit is used to determine that two phases corresponding to the low level are short-circuited when one of the three DC voltage signals is at a low level and the levels of the other two DC voltage signals are reduced.

[0035] In some optional embodiments, such as Figure 1 As shown, the short-circuit detection module to ground includes:

[0036] The full-bridge rectifier circuit is used to rectify the collected three-phase permanent magnet generator signal to generate a pulsating DC voltage signal. Figure 1 In the figure, the three-phase permanent magnet generator signal (PMG_A, PMG_B, PMG_C) is rectified by the full-bridge rectifier circuit composed of V1 to V6 to form a pulsating DC voltage signal;

[0037] A voltage divider circuit is used to divide the pulsating DC voltage signal. Figure 1 In the embodiment, the resistor R1 and the resistor R2 form a voltage divider circuit, and an attenuated pulsating DC voltage signal can be obtained after passing through the voltage divider circuit so as to match the breakdown voltage of the subsequent Zener diode V9;

[0038] The AC coupling circuit is used to remove the DC component of the pulsating DC voltage signal after voltage division, and obtain the ripple signal of the permanent magnet generator through rectification by diode V7. Figure 1 In the circuit, R3 and C1 form an AC coupling circuit;

[0039] The Zener diode V9 is arranged between the AC coupling circuit and the CPU component. When the signal of the three-phase permanent magnet generator is normal, the ripple signal cannot break through the Zener diode, and the CPU receives a low-level signal. When the three-phase permanent magnet generator is short-circuited to the ground, the ripple signal can break through the Zener diode, and the CPU receives a high-level signal.

[0040] In some optional implementations, an RC filter circuit consisting of a resistor R4 and a capacitor C2 is further provided between the Zener diode V9 and the CPU component.

[0041] In some optional implementations, the breakdown voltage of the Zener diode V9 is 5V.

[0042] In the first determination unit of the CPU component, when the voltage signal of the permanent magnet generator is normal, the peak value of the ripple voltage signal is less than 5V and cannot break down the Zener diode V9, and the output signal (PMG_SHORT) is sent to the CPU component at a low level; when the permanent magnet generator is short-circuited to the ground, the peak value of the ripple voltage signal is greater than 5V, and the Zener diode V9 is broken down. The voltage signal is filtered by the RC filter circuit composed of R4 and C2, and its peak value is maintained during the RC charging time, and the output signal (PMG_SHORT) is sent to the CPU component at a high level.

[0043] In some optional embodiments, reference Figure 2 , the open circuit and phase short circuit detection module includes:

[0044] Three isolation transformers are used to sample the phase-to-phase voltage of each two signals of the three-phase permanent magnet generator. Since the permanent magnet generator signal has no neutral line, the permanent magnet generator voltage cannot be directly sampled. Therefore, three isolation transformers are added here for voltage sampling. The voltage of any two phases in the three-phase permanent magnet generator signal (PMG_A, PMG_B, PMG_C) is connected to the transformer for phase-to-phase voltage sampling to obtain three AC voltage signals;

[0045] A voltage-dividing filter circuit is used to perform voltage-dividing filtering on the collected phase-to-phase voltage;

[0046] The peak sampling circuit is used to perform peak sampling on the voltage after voltage division and filtering to obtain three DC voltage signals.

[0047] like Figure 2 As shown, in the second determination unit of the CPU component, three DC voltage signals PMGINAB, PMGINBC and PMGINAC are sent to the CPU component, and the fault state is determined by judging the voltage value. If PMGINAB and PMGINAC change from high level to low level and the level of PMGINBC remains unchanged, the permanent magnet generator phase A is open; if PMGINAB and PMGINBC change from high level to low level and the level of PMGINAC remains unchanged, the permanent magnet generator phase B is open; if PMGINBC and PMGINAC change from high level to low level and the level of PMGINAB remains unchanged, the permanent magnet generator phase C is open; if PMGINAB, PMGINBC and PMGINAC all change from high level to low level, any two-phase or three-phase open circuit fault occurs in the permanent magnet generator.

[0048] In the third judgment unit of the CPU component, if PMGINAB is at a low level and the levels of PMGINBC and PMGINAC are reduced, it is determined that an AB phase-to-AB short circuit fault occurs in the permanent magnet generator; if PMGINBC is at a low level and the levels of PMGINAB and PMGINAC are reduced, it is determined that a BC phase-to-BC short circuit fault occurs in the permanent magnet generator; if PMGINAC is at a low level and the levels of PMGINAB and PMGINBC are reduced, it is determined that an AC phase-to-AC short circuit fault occurs in the permanent magnet generator.

[0049] In some optional implementations, the CPU component further includes:

[0050] The fault processing module is used to output a drive control signal for disconnecting the excitation and main contactor when the three-phase permanent magnet generator is short-circuited to the ground, the phase circuit is open, or the phase circuit is short-circuited.

[0051] In this embodiment, when the CPU component determines that the permanent magnet generator has any of the following fault types: short circuit to ground, open circuit of any phase, open circuit of any two phases or three phases, or short circuit between any two phases, the corresponding fault code is reported to the power supply system processor. At the same time, according to the fault type, the GPIO port of the CPU component will output the excitation and main contactor drive control signals, and combine with other components to ultimately control the on and off of the excitation and generator contactors, thereby improving the control and protection functions of the existing power generation system.

[0052] Simulate the above-mentioned short-circuit detection module to ground and the open circuit and phase-to-phase short circuit detection module

[0053] The short-circuit detection module of the permanent magnet generator is simulated based on the Saber circuit simulation software. During the simulation process, the simulation time is set to 0.05s and the simulation step size is 1us. The input peak value is set to 68.127V and the frequency is 1672Hz for the permanent magnet generator voltage signal. When the permanent magnet generator voltage signal is normal, the peak value of the ripple voltage signal is 3.76V, which cannot break down the Zener diode, and the output signal is 0V. The input peak value is set to 68.127V and the frequency is 1672Hz for the permanent magnet generator voltage signal. When the permanent magnet generator voltage signal A is short-circuited to the ground, the peak value of the ripple voltage signal is 7.23V, the Zener diode is broken down, and the output signal is 2.55V.

[0054] The open circuit and interphase short circuit detection module of the permanent magnet generator is simulated based on Saber circuit simulation software. The simulation time is set to 0.05s and the simulation step size is 1us. The input peak value is set to 48.991V and the frequency is 1200Hz. When the three-phase permanent magnet generator voltage signal is normal, the output signal PMGINAB is 4.49V, PMGINBC is 4.49V, and PMGINAC is 4.49V. The input peak value is set to 48.991V and the frequency is 1200Hz. When the A phase of the three-phase permanent magnet generator voltage signal is open circuit, the output signal PMGINAB is 2.25V, PMGINBC is 4.49V, and PMGINAC is 2.25V. Therefore, it can be seen that the signals PMGINAB and PMGINAC are reduced to 0.5 times of the original, and the signal PMGINBC remains unchanged, and it is judged that an open circuit fault occurs in phase A. The input peak value is set to 48.991V and the frequency is 1200Hz. When the three-phase permanent magnet generator has an AB phase short circuit fault, the output signal PMGINAB is 0V, PMGINBC is 4.49V, and PMGINAC is 4.49V. Therefore, it can be seen that the signal PMGINAB is 0V, and the signals PMGINAC and PMGINBC are unchanged, and it is judged that an AB phase short circuit fault occurs.

[0055] Although the present application has been described in detail above with general descriptions and specific implementation schemes, it is obvious to those skilled in the art that some modifications or improvements may be made to the present application. Therefore, these modifications or improvements made without departing from the spirit of the present application all fall within the scope of protection claimed in the present application.

Claims

1. A permanent magnet generator fault detection device, characterized in that: include: The ground short circuit detection module is used to connect the ripple signal after rectification and voltage division of the three-phase permanent magnet generator to the CPU component through the Zener diode V9; The open circuit and interphase short circuit detection module is used to sample the voltage of every two signals of the three-phase permanent magnet generator, obtain three DC voltage signals, and send the three DC voltage signals to the CPU component; The CPU components include: The first determination unit is used to determine that the three-phase permanent magnet generator is short-circuited to the ground when a high-level signal is connected via the Zener diode V9; A second determination unit is used to determine that the phases simultaneously associated with the two DC voltage signals are open when any two DC voltage signals among the three DC voltage signals change from a high level to a low level; The third determination unit is used to determine that two phases corresponding to the low level are short-circuited when one of the three DC voltage signals is at a low level and the levels of the other two DC voltage signals are reduced.

2. The permanent magnet generator fault detection device according to claim 1, characterized in that: The short-circuit-to-ground detection module comprises: A full-bridge rectifier circuit is used to rectify the collected three-phase permanent magnet generator signal to generate a pulsating DC voltage signal; A voltage divider circuit, used for dividing the pulsating DC voltage signal; The AC coupling circuit is used to remove the DC component of the divided pulsating DC voltage signal and obtain the ripple signal of the permanent magnet generator through rectification by diode V7; The Zener diode V9 is arranged between the AC coupling circuit and the CPU component. When the signal of the three-phase permanent magnet generator is normal, the ripple signal cannot break through the Zener diode, and the CPU receives a low-level signal. When the three-phase permanent magnet generator is short-circuited to the ground, the ripple signal can break through the Zener diode, and the CPU receives a high-level signal.

3. The permanent magnet generator fault detection device according to claim 2, characterized in that: An RC filter circuit consisting of a resistor R4 and a capacitor C2 is also provided between the Zener diode V9 and the CPU component.

4. The permanent magnet generator fault detection device according to claim 2, characterized in that: The breakdown voltage of the Zener diode V9 is 5V.

5. The permanent magnet generator fault detection device according to claim 1, characterized in that: The open circuit and phase short circuit detection module includes: Three isolation transformers are used to sample the phase-to-phase voltage of each two signals of the three-phase permanent magnet generator; A voltage-dividing filter circuit is used to perform voltage-dividing filtering on the collected phase-to-phase voltage; The peak sampling circuit is used to perform peak sampling on the voltage after voltage division and filtering to obtain three DC voltage signals.

6. The permanent magnet generator fault detection device according to claim 1, characterized in that: The CPU component also includes: The fault processing module is used to output a drive control signal for disconnecting the excitation and main contactor when the three-phase permanent magnet generator is short-circuited to the ground, the phase circuit is open, or the phase circuit is short-circuited.

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