Aviation brake fan motor controller

Abstract

The invention discloses an aviation brake fan motor controller, and belongs to the technical field of aviation brake fan motor controllers, the aviation brake fan motor controller comprises a control assembly module, a power board assembly module and a power supply assembly module, the control assembly module comprises a digital signal processing function circuit; the analog quantity conditioning circuit is electrically connected with the digital signal processing function circuit; the CPLD circuit is electrically connected with the digital signal processing function circuit; the discrete magnitude conditioning circuit is electrically connected with the CPLD circuit; the inverter driving PWM output circuit is electrically connected with the CPLD circuit; the power board assembly module comprises a first EMI filter to reduce mutual interference between each circuit and a power supply, an anti-reverse pre-charging circuit is electrically connected with the first EMI filter, a bus filter capacitor is electrically connected with the anti-reverse pre-charging circuit, and two three-phase inverters are electrically connected with the bus filter capacitor; the electromagnetic compatibility design is combined, so that the anti-interference capability and the stability of the system are improved.

Description

Technical Field

[0001] The invention relates to the technical field of aircraft brake fan motor controllers, and in particular to an aircraft brake fan motor controller. Background Art

[0002] In the field of modern aviation, the aircraft braking system is an important part of ensuring flight safety. During the landing process, the braking system needs to quickly reduce the speed of the aircraft to ensure that the aircraft can stop safely. During this process, the braking system will generate a lot of heat. The brake fan motor controller is used to control the operation of the main wheel cooling fan to dissipate heat in a timely and effective manner to prevent overheating damage.

[0003] The existing brake fan motor controller design has poor electromagnetic compatibility and fails to fully consider electromagnetic compatibility design, which makes the controller susceptible to interference in complex electromagnetic environments and affects the stability of the system. Summary of the invention

[0004] In order to solve the problems of the prior art, the present invention provides an aviation brake fan motor controller, comprising: a control component module, a power board component module and a power supply component module;

[0005] The power supply component module supplies power to the control component module and the power board component module;

[0006] The control component module comprises:

[0007] Digital signal processing functional circuit;

[0008] An analog quantity conditioning circuit, electrically connected to the digital signal processing functional circuit, for converting the collected voltage, current, and temperature information into digital quantities;

[0009] A CPLD circuit is electrically connected to the digital signal processing functional circuit;

[0010] A discrete quantity conditioning circuit, electrically connected to the CPLD circuit, for collecting discrete quantity signals;

[0011] An inverter drive PWM output circuit is electrically connected to the CPLD circuit and is used to transmit the calculated PWM to the power board component module to achieve motor control;

[0012] The power board assembly module comprises:

[0013] The first EMI filter is used to reduce the mutual interference between each circuit and the power supply;

[0014] An anti-reverse pre-charging circuit, electrically connected to the first EMI filter, for meeting the requirements of power supply anti-reverse connection protection and bus capacitor soft charging;

[0015] A bus filter capacitor is electrically connected to the anti-reverse pre-charging circuit and is used to filter the main power high-frequency chopping;

[0016] Two three-phase inverters are both electrically connected to the bus filter capacitor to realize the power inversion function and control two asynchronous motors respectively;

[0017] A PWM drive circuit, electrically connected to the inverter drive PWM output circuit, for drive signal isolation amplification, interlocking, drive clamping, and drive undervoltage detection and protection;

[0018] The temperature sampling circuit, voltage sampling circuit and current sampling circuit are all electrically connected to the digital signal processing functional circuit. The temperature sampling circuit is used to collect the temperature of the power board and the heat dissipation component, the voltage sampling circuit is used to collect the three-phase phase voltage and the two-way DC bus voltage, and the current sampling circuit is used to collect the three-phase phase current and the DC bus current.

[0019] Further, the power supply assembly module includes: a 270V high voltage DC power supply and a 28V auxiliary power supply;

[0020] The 270V high-voltage DC power supply is electrically connected to the first EMI filter and serves as a power supply for two asynchronous motors with a power of 400W; the 28V auxiliary power supply is used to power the various components of the control component module and the power board component module.

[0021] Furthermore, the 28V auxiliary power supply includes:

[0022] Input filter circuit;

[0023] A tank circuit electrically connected to the input filter circuit;

[0024] a voltage spike suppression circuit, electrically connected to the energy storage circuit;

[0025] A first power conversion circuit, electrically connected to the voltage spike suppression circuit;

[0026] A voltage monitoring circuit, electrically connected to the voltage spike suppression circuit;

[0027] The 28V auxiliary power supply is converted from 28V by the first power conversion circuit to provide 5 output power supplies, one of which is a 28V output power supply, which is electrically connected to the second EMI filter, the second EMI filter is electrically connected to the second power conversion circuit, and the second power conversion circuit is electrically connected to the PWM drive circuit, the temperature sampling circuit, the voltage sampling circuit and the current sampling circuit, and is used for secondary power conversion required for temperature, voltage and current sampling;

[0028] One channel is a 28V output power supply, which supplies power to the driver board and is mainly used to drive the isolated power supply;

[0029] One channel is a 5VDC output power supply, which outputs 3.3VDC and 1.9VDC through the power conversion circuit to power the digital signal processing function circuit and the external memory chip respectively;

[0030] One is an analog 15V power supply, which supplies power to the temperature sampling and conditioning circuit of the control component module;

[0031] One channel is an analog 5VAC power supply, which supplies power to the DC bus voltage conditioning circuit and the LRM control circuit.

[0032] Furthermore, the control component module also includes: a communication circuit, which is electrically connected to the digital signal processing functional circuit, and the communication circuit also performs data communication with the host computer through an RS422 bus.

[0033] Furthermore, it also includes: a manual switch and an automatic switch, both electrically connected to the digital signal processing functional circuit;

[0034] When in the automatic switch position, the RIU constantly judges the logic and outputs the start / stop motor working instructions through the bus, and is not restricted by whether the uploaded self-test information passes or fails;

[0035] Only when the ground power supply is enabled, turn the automatic switch to the manual switch, upload the self-test information to the RIU through the bus, and directly control the motor to stop automatically after working for 25 minutes. If the motor needs to continue working, turn the manual switch to the automatic switch, and then turn the automatic switch to the manual switch;

[0036] When the manual switch is turned to the automatic switch, the manual and automatic position status changes and self-test information are uploaded to the RIU through the bus. At the same time, the RIU constantly judges the logic and outputs the working instructions of starting / closing the motor through the bus;

[0037] The asynchronous motor speed regulation adopts a vector control method based on position-free technology with dual closed-loop control of speed and flux; in multi-loop control, the cutoff frequency of the inner loop must be greater than that of the outer loop, and the current loop frequency and the chopping frequency are the same; asynchronous motor control includes dual-loop speed regulation of speed loop and current loop.

[0038] Furthermore, the inverter driving PWM output circuit comprises:

[0039] The FPGA circuit is electrically connected to the CPLD circuit;

[0040] An optical coupling isolation module, electrically connected to the FPGA circuit;

[0041] A level conversion module, electrically connected to the optical coupling isolation module;

[0042] The level conversion module is also electrically connected to the PWM driving circuit. The PWM signal sent by the digital signal processing functional circuit is finally output as a TTL type 0-5V voltage signal after being isolated by the optocoupler isolation module and level converted by the level conversion module.

[0043] Furthermore, the control component module, the power board component module and the power supply component module are isolated by shielding the chassis cavity to reduce internal and external interference.

[0044] Furthermore, the grounding ends of the control component module, the power board component module and the power supply component module are directly connected to the shielded chassis; the external grounding of the shielded chassis is achieved by installing grounding bolts and connecting to the rack through the grounding bolts.

[0045] Furthermore, the power harness in the power assembly module adopts a single-point grounding method, and the shielding layer is crimped 360° at the connector interface.

[0046] Furthermore, the power ground is divided into digital ground and analog ground in the PCB, the analog ground and the digital ground are connected at a single point inside, and the digital ground is insulated from the shielding box, and the analog ground is connected to the shielding box in a multi-point manner.

[0047] The beneficial effect of the technical solution provided by the embodiment of the present invention is that the filter used in the present invention effectively suppresses various high-frequency interferences and high-order harmonics in the power supply and signal, thereby ensuring the purity of the power supply and signal.

[0048] Secondly, through shielding design and grounding design, the electromagnetic compatibility of the system is significantly improved, ensuring the stable operation of the controller in a complex electromagnetic environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 It is a system function diagram of an aviation brake fan motor controller provided by the present invention;

[0051] Figure 2 It is a diagram of the relationship between an aircraft brake fan motor controller and an external interconnection provided by the present invention;

[0052] Figure 3 It is a hardware structure diagram of an aviation brake fan motor controller provided by the present invention;

[0053] Figure 4 It is a hardware structure diagram of a control component module provided by the present invention;

[0054] Figure 5 It is a cross-link diagram of a power component module provided by the present invention;

[0055] Figure 6 It is a hardware structure diagram of a power board assembly module provided by the present invention;

[0056] Figure 7 It is a schematic diagram of an inverter driving PWM output circuit provided by the present invention;

[0057] Figure 8 It is a differential and common mode noise propagation path diagram provided by the present invention;

[0058] Fig. 9 It is a schematic diagram of decoupling of an EMI filter provided by the present invention;

[0059] Fig.10 This is a PT1000 measurement principle diagram provided by the present invention;

[0060] Fig.11 It is a DSP power supply circuit diagram provided by the present invention;

[0061] Fig.12 It is a RS422 driving circuit diagram provided by the present invention;

[0062] Fig.13 The invention provides an inverter driving PWM output circuit diagram. DETAILED DESCRIPTION

[0063] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0064] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0065] See also Figure 1-Figure 13 , an aviation brake fan motor controller, comprising: a control component module, a power board component module and a power supply component module.

[0066] Among them, the control component module and the power component module are both designed in the LRM structure; the core digital signal processing functional circuit of the control component module adopts a single processor channel architecture, and the control component module includes: digital signal processing functional circuit, analog quantity conditioning circuit, CPLD circuit (programmable logic device), discrete quantity conditioning circuit, inverter drive PWM output circuit, hardware BIT circuit and communication circuit.

[0067] The analog quantity conditioning circuit is electrically connected to the digital signal processing functional circuit, and is used to convert the collected voltage, current, and temperature information into digital quantities; the CPLD circuit is electrically connected to the digital signal processing functional circuit; the discrete quantity conditioning circuit is electrically connected to the CPLD circuit, and is used to collect discrete quantity signals such as machine position number and discrete control instructions; the hardware BIT circuit is electrically connected to the digital signal processing functional circuit, and for faults with strong real-time requirements such as severe overcurrent and power tube short circuit, the hardware comparison output protection is directly adopted to cut off the power output in real time; the communication circuit is electrically connected to the digital signal processing functional circuit, and the communication circuit also communicates with the RS422 of the host computer and the RS422 of the ground maintenance equipment to issue control commands and upload real-time operation data.

[0068] RS422 is a full-duplex design. In terms of electrical connection, RS422 adopts a five-wire system, 2 transmit lines, 2 receive lines, and 1 ground line. According to the requirements, common-mode inductors are connected to the RS422 transmit positive terminal (TX+) and the transmit negative terminal (TX-) to suppress common-mode noise interference; the receiving terminal is connected to a 120Ω matching resistor; at the same time, a two-way communication dedicated TVS tube is connected to the ground at the input and output ends.

[0069] The digital signal processing function circuit processes the collected data information and issues control instructions to realize functions such as motor control, BIT, serial communication, storage and recording, and status detection; the inverter drive PWM output circuit is electrically connected to the CPLD circuit to transmit the calculated PWM to the power board component module to realize motor control.

[0070] The digital signal processing function circuit is DSPF28335. The voltage values ​​required for DSPF28335 to work are 3.3V and 1.9V, which are 3.3V I / O voltage, 3.3V analog voltage and 1.9V core voltage respectively. When designing the power supply circuit of DSPF28335, it is necessary to ensure the stability of power supply and pay attention to the power-on sequence. For TMS320F28335, the 1.9V core needs to be powered on before 3.3V I / O and 3.3V analog voltage to avoid system failure caused by the uncertain state of 3.3V I / O after power-on. The 3.3V and 1.9V power supplies use the fast-response high-precision power supply chip TPS70302.

[0071] The clock circuit in DSPF28335 uses a 30MHz active crystal oscillator connected to the XCLKIN pin of DSPF28335 to provide a clock reference for DSPF28335. The crystal oscillator model is ZA71F. The reset circuit in DSPF28335 has watchdog and voltage monitoring functions, and can automatically reset in the event of program runaway or power failure. The reset signal is provided by the CPLD circuit.

[0072] Through the JTAG interface circuit, the connection between DSPF28335 and the emulator can be realized, and the internal test of DSPF28335 and the simulation and debugging of the system can be realized. Using a computer and an emulator, the online debugging and program burning of the program can be realized through the JTAG interface circuit.

[0073] The power board component module includes: a first EMI filter, an anti-reverse pre-charging circuit, a bus filter capacitor, two three-phase inverters, a PWM drive circuit, a temperature sampling circuit, a voltage sampling circuit and a current sampling circuit.

[0074] The first EMI filter is electrically connected to the power component module, which is divided into main power filtering and weak current filtering. The first EMI filter is used to reduce mutual interference between each circuit and the power supply; the anti-reverse pre-charging circuit is electrically connected to the first EMI filter to meet the power reverse connection protection and bus capacitor soft charging requirements; the two three-phase inverters are electrically connected to the bus filter capacitor to realize the power inversion function and control the two asynchronous motors respectively; the PWM drive circuit is electrically connected to the inverter drive PWM output circuit for drive signal isolation amplification, interlocking, drive clamping and drive undervoltage detection and protection.

[0075] The PWM output circuit includes: an FPGA circuit, an optocoupler isolation module, and a level conversion module. The FPGA circuit is electrically connected to the CPLD circuit; the optocoupler isolation module is electrically connected to the FPGA circuit, the level conversion module is electrically connected to the optocoupler isolation module, and the level conversion module is also electrically connected to the PWM drive circuit. The PWM signal emitted by the digital signal processing function circuit is finally output as a TTL type 0-5V voltage signal after isolation by the optocoupler isolation module and level conversion by the level conversion module.

[0076] The anti-reverse pre-charge circuit requires the controller to have soft start capability and be able to prevent reverse connection. It can meet the requirements of 14A starting current under low temperature extreme environmental conditions and 9A low temperature continuous working current after 2s. The soft charging MOS tube is the N-channel 600V / 35A field effect tube IPB60R060C7. The anti-reverse diode is the STTH30AC06C with 30A peak average forward current and 600V peak reverse repetitive voltage.

[0077] The temperature sampling circuit, voltage sampling circuit and current sampling circuit are all electrically connected to the digital signal processing functional circuit. The temperature sampling circuit is used to collect the temperature of the power board and the heat dissipation component, the voltage sampling circuit is used to collect the three-phase phase voltage and the two-way DC bus voltage, and the current sampling circuit is used to collect the three-phase phase current and the DC bus current.

[0078] The current sampling circuit uses the ACS720KLATR-65AB-T chip from the ACS series, which provides excellent magnetic coupling and current isolation up to 3000VRMS, and has an overcurrent alarm function. The ACS720KLATR-65AB-T converts the current signal into a voltage signal and inputs it into the DSP through a conditioning circuit. Its operating current range is -65A to 65A.

[0079] The ACS720KLATR-65AB-T chip converts the current signal into a voltage signal and outputs it to the signal conditioning circuit. The operational amplifier used is JOP8552, which is a precision dual-channel amplifier produced by 58 Institute with a bandwidth of 1MHz and supports rail-to-rail output.

[0080] The output voltage of the ACS720KLATR-65AB-T sensor is V OUT =0.0205*I d +1.5, the voltage sampled by the current sensor is sent to the operational amplifier, and the voltage sent to the DSP is:

[0081]

[0082] The voltage sampling circuit adopts an isolated voltage sampling solution, and the voltage sampling circuit adopts the GH1147JA chip. This chip adopts excellent optocoupler technology, plus built-in Sigma-Delta (Σ-Δ) analog-to-digital converter, chopper-stabilized amplifier and fully differential circuit topology, with excellent isolation mode noise suppression performance, and has the characteristics of low offset, high gain accuracy and stability.

[0083] The bus voltage is sampled by resistor voltage division. GH1147JA collects the voltage on the 2k resistor and then transmits it to DSP for processing through the conditioning circuit. The input voltage of this system is 270V, and the external circuit resistor voltage division is the original 0.003623.

[0084] The differential amplifier circuit has an amplification ratio of 1.1, so the voltage input to the DSP end is: V DSP =V BUS *0.003623*1.1, so the actual voltage can be obtained from the read data:

[0085]

[0086] The three power component temperature signals are the power board component heat sink temperature and the two motor temperatures. They are conditioned using a single-ended non-isolated processing method. The temperature signal input voltage range is 0 to 5V. The circuit principle and the parameter selection of resistors and capacitors are the same as those of the bus current acquisition circuit.

[0087] The temperature is collected through PT1000. PT1000 is a platinum thermal resistor. Its resistance is proportional to the change in temperature. The relationship between the resistance and temperature change of PT1000 is: when the temperature of PT1000 is 0℃, its resistance is 1000 ohms, and at 100℃, its resistance is about 1385.005 ohms. Its industrial principle is: the resistance will increase at a uniform rate as the temperature rises.

[0088] The temperature acquisition of PT1000 is a two-wire acquisition method, which is PT1+, PT1-, PT2+, PT2-, PT3+, PT3-. The PT1000 acquisition circuit uses the Wheatstone unbalanced bridge method to condition the PT1000 resistance signal, convert the PT1000 resistance value to be measured into a voltage value, and amplify the voltage signal through the operational amplifier and perform AD sampling; the PT1000 measurement principle is as follows Fig.10 shown.

[0089] The current source of the PT1000 temperature acquisition circuit is set to i=1mA current source, the resistance input range of the PT1000 resistor is about 785Ω~1.975KΩ, and the bridge output voltage range is -0.166~0.1136V. The signal is amplified by the proportional amplifier circuit, and the voltage range is adjusted to the AD input allowable range. The PT1000 temperature sensor signal is a slow-changing signal. For the input high-frequency noise signal, a low-pass RC network is added to the input end to filter the input signal, suppress the differential mode and common mode noise respectively, and effectively filter out the signal noise.

[0090] The power supply component module includes: a 270V high-voltage DC power supply and a 28V auxiliary power supply. The 270V high-voltage DC power supply is electrically connected to the first EMI filter and serves as a power supply for two asynchronous motors with a power of 400W; the 28V auxiliary power supply is used to power various components of the control component module and the power board component module.

[0091] Since the 28V auxiliary power supply has no external input power interface, it is not necessary to complete the 28V input power supply characteristic test requirements. According to the protocol requirements, the whole machine 270V power supply 200ms interruption characteristic test, in addition, the auxiliary power supply needs to provide a detection input 28V voltage simulation. High-voltage DC 270V, 28V, the three-phase current of the two asynchronous motors, and the motor temperature all need to be converted into analog-to-digital for motor control and health detection.

[0092] The 28V auxiliary power supply includes: an input filter circuit, an energy storage circuit, a voltage spike suppression circuit, a first power conversion circuit and a voltage monitoring circuit; the energy storage circuit is electrically connected to the input filter circuit, the voltage spike suppression circuit is electrically connected to the energy storage circuit, the first power conversion circuit is electrically connected to the voltage spike suppression circuit, and the voltage monitoring circuit is electrically connected to the voltage spike suppression circuit;

[0093] The 28V is converted by the first power conversion circuit and provides a total of 5 power outputs, which are as follows:

[0094] a) One 28V is used to power the power board, which is electrically connected to the second EMI filter. The second EMI filter is electrically connected to the second power conversion circuit. The second power conversion circuit is electrically connected to the temperature sampling circuit, the voltage sampling circuit and the current sampling circuit, and is used for the secondary power conversion required for temperature, voltage and current sampling. The power conversion circuit converts 28V to 12V power and 5V power to power the temperature sampling circuit, the voltage sampling circuit, the current sampling circuit and the PWM drive circuit respectively. The 28V to 12V chip uses the WK392812S power module, and the 28V to 5V chip uses the WKWK3028515D power module.

[0095] b) One 28V is used to power the driver board, which is mainly used to power 15-way driver isolation power supply.

[0096] c) One digital 5VDC output power supply, which outputs 3.3VDC and 1.9VDC through the power conversion circuit to power the digital signal processing function circuit, CPLD, RS422 and external memory chip respectively.

[0097] d) One analog 5VAC (connected to the digital 5V through a magnetic bead) is used to power the DC bus voltage conditioning and the conditioning circuit that controls the LRM;

[0098] e) One analog 15V is used to power the temperature sampling and conditioning circuits of the control component module.

[0099] In order to make the product compatible with the 270VDC power supply characteristics on board, power supply compatibility design was carried out. See Table 1 for details.

[0100] Table 1 Power supply compatibility design solution

[0101]

[0102]

[0103] The power component module supplies power to the main power circuit through the DC bus on the one hand, and supplies power to the control circuit through the DC-DC power module on the other hand. Therefore, it is necessary to add an EMI filter composed of common-mode inductors, differential-mode inductors, X capacitors, Y capacitors, etc. before the two power supply paths to reduce mutual interference between the circuits and power supplies.

[0104] Power supply noise is a type of electromagnetic interference, and the spectrum of its conducted noise is roughly 10kHz to 30MHz, up to 150MHz. According to the different propagation directions, power supply noise can be divided into two categories: one is the external interference introduced from the power supply line, and the other is the noise generated by electronic equipment and conducted through the power line. This shows that noise is a bidirectional interference signal, and electronic equipment is both the object of noise interference and a noise source. From the perspective of formation characteristics, noise interference is divided into differential mode interference and common mode interference. Differential mode interference is the noise between two power lines (referred to as line-to-line), and common mode interference is the noise from two power lines to the earth (referred to as line-to-ground). Therefore, for EMI filters, on the one hand, it is necessary to filter out the external electromagnetic interference introduced from the power line, and on the other hand, it can also prevent the equipment itself from emitting noise interference to the outside, so as not to affect the normal operation of other electronic equipment in the same electromagnetic environment. At the same time, EMI filters should play a suppressive role in both differential mode and common mode interference.

[0105] EMI filters are divided into active and passive types. The essence of active filter technology is to detect noise signals and generate anti-phase current for real-time compensation. It has better low-frequency filtering effect and is suitable for occasions with small working current. Passive EMI filter is a bidirectional low-pass filter composed of inductors and capacitors. It has a simple structure and good high-frequency filtering effect. It can effectively suppress power supply noise, improve the anti-interference ability of electronic equipment and the reliability of the system, and can be widely used in motor controller applications. The basic circuit of EMI filter is as follows: Fig. 9 As shown, the five-terminal device has two input terminals, two output terminals and a ground terminal. When in use, the shell should be connected to the ground. The circuit includes a common-mode choke (also known as a common-mode inductor) L, a filter capacitor C X1 ~C X2 and C Y1 ~C Y2 .

[0106] L has no effect on differential mode interference, but when common mode interference occurs, since the magnetic flux directions of the two coils are the same, the total inductance increases rapidly after coupling, so it presents a large inductive reactance to the common mode signal, making it difficult to pass through, so it is called a common mode choke. Its two coils are respectively wound on low-loss, high-permeability ferrite magnetic rings. When common mode current passes through, the magnetic fields on the two coils will strengthen each other. The differential mode choke can be realized by the leakage inductance of the common mode choke, and can also be wound separately.

[0107] It should be pointed out that when the rated current is large, the wire diameter of the common mode choke should also be increased accordingly so that it can withstand larger currents. In addition, appropriately increasing the inductance can improve the low-frequency attenuation characteristics; C X1 and C X2 Film capacitors are used to filter out differential mode interference. Y1 and C Y2 Connecting it across the output end and grounding the midpoint of the capacitor can effectively suppress common-mode interference. To reduce leakage current, the capacitance must not exceed the specified value and the midpoint of the capacitor should be connected to the ground.

[0108] The main technical parameters of EMI filters are: rated voltage, rated current, leakage current, test voltage, insulation resistance, DC resistance, operating temperature range, operating temperature rise, insertion loss, dimensions, weight, etc. Among them, insertion loss (also known as insertion attenuation) is the most important parameter and the main indicator for evaluating the performance of EMI filters. Insertion loss IL is a function of frequency and is expressed in dB. Assume that the noise power transmitted to the load before and after the electromagnetic interference filter is inserted is P1 and P2 respectively, the formula is:

[0109]

[0110] Insertion loss is expressed in decibels (dB). The larger the decibel value, the stronger the ability to suppress noise interference.

[0111] Since the EMI filter uses a low-pass network composed of passive components such as inductors and capacitors, the resonant frequency of the EMI filter network and its terminal load must be considered. Any EMI filter network can be equivalent to a network structure that matches the common-mode interference equivalent circuit and the differential-mode interference equivalent circuit. Therefore, the common-mode inductor L CM and the equivalent common mode capacitance C Y The series resonant frequency f oc , and the differential mode inductance L DM (It includes the differential mode inductance formed by the common mode coil and the independent differential mode suppression inductance) and the equivalent differential mode capacitance C X The series resonant frequency f od Right now:

[0112]

[0113] Among them, f oc and f od They must be far away from the stopband range to achieve the suppression effect. The lower the cut-off frequency, the better the filtering performance, but the volume and weight will also increase.

[0114] EMI filters must follow the following principles:

[0115] 1) The filter must meet the requirements of the load circuit operating frequency and the frequency to be suppressed. If the frequency to be suppressed is very close to the useful signal frequency, a filter with a very steep frequency characteristic is required;

[0116] 2) At the required frequency, the impedance design of the filter must follow the impedance mismatch principle. If the load is high impedance, the output impedance of the filter should be low impedance; if the power supply or interference source impedance is low impedance, the output impedance of the filter should be high impedance;

[0117] 3) The filter must have a certain voltage resistance. The filter should be selected according to the rated voltage of the power supply and the interference source, so that it has a sufficiently high rated voltage to ensure that it can work reliably under all expected working conditions and can withstand the impact of input instantaneous high voltage. This is a specific measure of safety indicators;

[0118] 4) The current allowed to pass through the filter should be consistent with the rated current of the circuit for continuous operation (i.e. 1.2 times the working current). If the current allowed to pass through is too high, the size and weight of the filter will be increased, and if the current allowed to pass through is too low, the reliability of the filter will be reduced;

[0119] 5) The filter should have sufficient mechanical strength, simple structure, light weight, small size, easy installation, safety and reliability.

[0120] This filter scheme intends to use a multi-stage cascaded low-pass circuit combination network as a power supply EMI filter. This form of filter has the advantages of small component parameters, good high-frequency performance, and high cost performance. It has good attenuation characteristics in the stopband range and can meet the index requirements of the filter insertion loss to achieve the purpose of suppressing interference signals. When designing parameters, the spectrum and amplitude of unintentional emission sources such as the DC / DC power supply module, crystal oscillator and switch tube inside the motor controller should also be compared with the CE102 limit value to obtain the required insertion loss of the filter, and then the filter parameters are obtained according to the termination impedance characteristics.

[0121] The power input line and output line inside the filter are separated to avoid direct coupling between the two and cause the filter to be bypassed. The filter housing adopts full metal packaging and is integrated with the power input connector and installed at the power inlet of the controller, which can reduce the contact resistance and shorten the ground loop, which can reduce the interference amplitude and spectrum width of the interference source and reduce the interference to the outside world, so that the controller has excellent electromagnetic compatibility.

[0122] In addition, in order to keep the bus voltage of the motor controller stable and filter out high-frequency ripples, it is necessary to add support capacitors on the inverter bus. Support capacitors can be film capacitors, which have the advantages of high dielectric constant, small size, large capacity, and strong dv / dt and di / dt absorption capabilities. At the same time, it is also necessary to connect the parallel film capacitors and ceramic capacitors to the input end of the DC-DC power module or chip for decoupling to reduce high-frequency clutter on the power line.

[0123] It should be noted that the digital signal processing functional circuit is electrically connected to a manual switch and an automatic switch, so that the controller has two working modes: one working mode is to control the main wheel cooling fan by controlling the motor controller through cockpit signals; the other working mode is manual, and the ground operator manually operates the motor controller to control the main wheel cooling fan.

[0124] The controller control instruction judgment logic is as follows: when in the automatic switch position, RIU constantly judges the logic, outputs the start / stop motor working instructions through the bus, and is not restricted by whether the uploaded self-test information passes or not; only when the ground power is enabled, the automatic switch is turned to the manual switch, the self-test information is uploaded to RIU through the bus, and the motor is directly controlled to stop automatically after 25 minutes of operation. If the motor needs to continue working, the manual switch needs to be turned to the automatic switch, and then from the automatic switch to the manual switch; when the manual switch is turned to the automatic switch, the manual and automatic position status changes and self-test information are uploaded to RIU through the bus. At the same time, RIU constantly judges the logic and outputs the start / stop motor working instructions through the bus.

[0125] The asynchronous motor speed regulation adopts a vector control method based on position-free technology with dual closed-loop control of speed and flux; in multi-loop control, the cutoff frequency of the inner loop must be greater than that of the outer loop, and the current loop frequency and the chopping frequency are the same; the motor control includes dual-loop speed regulation of the speed loop and the current loop.

[0126] In order to meet the requirements of steady-state speed accuracy, the speed is sampled by digital calculation, and the rotor position is calculated based on the motor phase voltage and phase current in a position-free manner. The motor speed is then calculated using the rotor position increment. According to simulation and experimental data, the error between the estimated rotor position and the actual position is not large, and the speed calculation error should be equivalent to the rotor position obtained after decoding using a resolver. In addition to the motor speed pulsation and control error, and the motor speed is controlled in a certain filtering method and other processing, the overall speed accuracy can meet the requirements.

[0127] Large impact currents may be generated during the power-on of the motor controller and the process of starting the motor. During the power-on process, due to the large busbar support capacitor in the motor control, the equivalent impedance is very low during the capacitor power-on charging process, which is easy to generate impact currents, even reaching hundreds of A levels, but the duration is very short, generally (1~2) ms, and the energy is not high, which can be achieved by using a pre-charging circuit; during the motor starting process, in order to achieve greater acceleration and shorter starting time, the general starting current is 3~5 times the rated current, especially in the starting stage without position control, which is more obvious. Therefore, in order to meet the starting current index requirements, a starting control algorithm with current limiting capability is required. By selecting the appropriate limited current value, the balance point between the starting time and the starting current is found, so that the controller needs to have soft starting capability, and the starting current is less than 14A under low temperature extreme environmental conditions.

[0128] According to the host requirements, the load on the aircraft power supply during operation of the product cannot exceed the rated capacity. Due to the large interference of motor control products, in order to avoid affecting the onboard power supply and other electrical equipment, the current ripple and voltage ripple are also required to be controlled within a certain range. The electrical and electronic components in the controller should be compatible with the characteristics of the aircraft power supply; the design should meet the requirements of GJB181B-2012.

[0129] It should also be noted that the capacitor is connected to the input end of the DC-DC power module or chip for decoupling to reduce high-frequency noise on the power line.

[0130] The anti-interference design of printed circuit boards is not only related to layout, but also has a considerable relationship with wiring. The following principles should be followed when wiring PCBs:

[0131] 1) Pay attention to the wiring priority: key signal lines first, dense areas first. Provide dedicated wiring layers for key signals to ensure the minimum loop area and avoid signal lines from forming self-loops between different layers;

[0132] 2) Keep the wiring length as short as possible, avoid sharp angles and right angles, and avoid wiring with one end floating. According to the current of the printed circuit board, try to thicken the power line and ground line to reduce the loop impedance. In addition to thickening the power line and ground line as much as possible, a certain space should be left between the power line and the ground line to install a decoupling capacitor with good high-frequency characteristics;

[0133] 3) Make the direction of power line and ground line consistent with the direction of data transmission, which helps to enhance the anti-noise ability;

[0134] 4) The control circuit is separated from the output circuit, and single-point grounding is adopted. Large-area grounding is easy to induce antenna effect, so large-area grounding is not adopted.

[0135] Grounding technology is one of the important contents of electromagnetic compatibility design. Improper grounding will increase interference. In order to prevent various circuits from interfering with each other during work and make them work compatibly with each other, grounding is divided into different types according to the nature of the circuit; in this application, the shielding body grounding includes two parts, shielding chassis grounding and shielding cable grounding.

[0136] The control component module, power board component module and power supply component module are isolated by shielded chassis chambers to reduce internal and external interference; the grounding terminals of the power supply, PCB board, control board and driver board in the control component module, power board component module and power supply component module are directly connected to the chassis, and the nearest grounding method is adopted, and they are connected to the chassis shell with bolts at the shortest distance, and the contact surface is kept clean and flat to reduce the grounding impedance; the external grounding of the shielded chassis adopts the method of installing grounding bolts, which are connected to the frame through the grounding bolts, and the threads are polished to maintain good electrical connection.

[0137] The power harness has a lower frequency and uses a single-point grounding method. The shielding layer is crimped 360° at the connector interface and then connected to the grounding point. The signal harness uses a multi-point grounding method to ground the shielding layer at both ends of the cable.

[0138] The power grounding design first divides the digital ground and analog ground in the PCB design. The analog ground and digital ground are connected at a single point inside the module, and the digital ground of the digital module is insulated from the module shielding box. The analog ground of the RF module is connected to the module shielding box in a multi-point manner, and the power return line must not be connected to the housing. Then the inside of the power module is selected as the grounding point, and the grounding loop is designed according to the input and output ports of the set digital signal and analog signal; in order to avoid the formation of grounding loops during the design process, the multi-channel output of the power module is used to power each module separately.

[0139] The controller can realize precise control of motor speed, real-time detection of fault status during system operation, and corresponding fault handling strategies according to fault level and fault type. It can also record fault information to NVRam. In ground maintenance working mode, it can upload fault information in NVRam to the host computer. It also has the function of machine position identification, and can load corresponding configuration table files according to different load characteristics, thus ensuring the versatility of the controller.

[0140] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0141] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An aircraft brake fan motor controller, characterized in that: include: Control component module, power board component module and power supply component module; The power supply component module supplies power to the control component module and the power board component module; The control component module comprises: Digital signal processing functional circuit; An analog quantity conditioning circuit, electrically connected to the digital signal processing functional circuit, for converting the collected voltage, current, and temperature information into digital quantities; A CPLD circuit is electrically connected to the digital signal processing functional circuit; A discrete quantity conditioning circuit, electrically connected to the CPLD circuit, for collecting discrete quantity signals; An inverter drive PWM output circuit is electrically connected to the CPLD circuit and is used to transmit the calculated PWM to the power board component module to achieve motor control; The power board assembly module comprises: The first EMI filter is used to reduce the mutual interference between each circuit and the power supply; An anti-reverse pre-charging circuit, electrically connected to the first EMI filter, for meeting the requirements of power supply anti-reverse connection protection and bus capacitor soft charging; A bus filter capacitor is electrically connected to the anti-reverse pre-charging circuit and is used to filter the main power high-frequency chopping; Two three-phase inverters are both electrically connected to the bus filter capacitor to realize the power inversion function and control two asynchronous motors respectively; A PWM drive circuit, electrically connected to the inverter drive PWM output circuit, for drive signal isolation amplification, interlocking, drive clamping, and drive undervoltage detection and protection; The temperature sampling circuit, voltage sampling circuit and current sampling circuit are all electrically connected to the digital signal processing functional circuit. The temperature sampling circuit is used to collect the temperature of the power board and the heat dissipation component, the voltage sampling circuit is used to collect the three-phase phase voltage and the two-way DC bus voltage, and the current sampling circuit is used to collect the three-phase phase current and the DC bus current.

2. The aircraft brake fan motor controller according to claim 1, characterized in that: The power supply assembly module includes: a 270V high-voltage DC power supply and a 28V auxiliary power supply; The 270V high-voltage DC power supply is electrically connected to the first EMI filter and serves as a power supply for two asynchronous motors with a power of 400W; the 28V auxiliary power supply is used to power the various components of the control component module and the power board component module.

3. The aircraft brake fan motor controller according to claim 2, characterized in that: The 28V auxiliary power supply includes: Input filter circuit; A tank circuit electrically connected to the input filter circuit; a voltage spike suppression circuit, electrically connected to the energy storage circuit; A first power conversion circuit, electrically connected to the voltage spike suppression circuit; A voltage monitoring circuit, electrically connected to the voltage spike suppression circuit; The 28V auxiliary power supply is converted from 28V by the first power conversion circuit to provide 5 output power supplies, one of which is a 28V output power supply, which is electrically connected to the second EMI filter, the second EMI filter is electrically connected to the second power conversion circuit, and the second power conversion circuit is electrically connected to the PWM drive circuit, the temperature sampling circuit, the voltage sampling circuit and the current sampling circuit, and is used for secondary power conversion required for temperature, voltage and current sampling; One channel is a 28V output power supply, which supplies power to the driver board and is mainly used to drive the isolated power supply; One channel is a 5VDC output power supply, which outputs 3.3VDC and 1.9VDC through the power conversion circuit to power the digital signal processing function circuit and the external memory chip respectively; One is an analog 15V power supply, which supplies power to the temperature sampling and conditioning circuit of the control component module; One channel is an analog 5VAC power supply, which supplies power to the DC bus voltage conditioning circuit and the LRM control circuit.

4. The aircraft brake fan motor controller according to claim 1, characterized in that: The control component module also includes: a communication circuit, which is electrically connected to the digital signal processing functional circuit, and the communication circuit also performs data communication with the host computer through the RS422 bus.

5. The aircraft brake fan motor controller according to claim 1, characterized in that: Also includes: The manual switch and the automatic switch are both electrically connected to the digital signal processing functional circuit; When in the automatic switch position, the RIU constantly judges the logic and outputs the start / stop motor working instructions through the bus, and is not restricted by whether the uploaded self-test information passes or fails; Only when the ground power supply is enabled, turn the automatic switch to the manual switch, upload the self-test information to the RIU through the bus, and directly control the motor to stop automatically after working for 25 minutes. If the motor needs to continue working, turn the manual switch to the automatic switch, and then turn the automatic switch to the manual switch; When the manual switch is turned to the automatic switch, the manual and automatic position status changes and self-test information are uploaded to the RIU through the bus. At the same time, the RIU constantly judges the logic and outputs the working instructions of starting / closing the motor through the bus; The asynchronous motor speed regulation adopts a vector control method of speed and flux dual closed-loop control based on position-free technology; in multi-loop control, the cutoff frequency of the inner loop must be greater than the outer loop, and the current loop frequency and the chopping frequency are the same; asynchronous motor control includes speed loop and current loop dual-loop speed regulation.

6. The aircraft brake fan motor controller according to claim 1, characterized in that: The inverter driving PWM output circuit comprises: The FPGA circuit is electrically connected to the CPLD circuit; An optical coupling isolation module, electrically connected to the FPGA circuit; A level conversion module, electrically connected to the optical coupling isolation module; The level conversion module is also electrically connected to the PWM driving circuit. The PWM signal sent by the digital signal processing functional circuit is finally output as a TTL type 0-5V voltage signal after being isolated by the optocoupler isolation module and level converted by the level conversion module.

7. The aircraft brake fan motor controller according to claim 1, characterized in that: The control component module, the power board component module and the power supply component module are isolated by using a shielded chassis cavity to reduce internal and external interference.

8. The aircraft brake fan motor controller according to claim 7, characterized in that: The grounding ends of the control component module, the power board component module and the power supply component module are directly connected to the shielded chassis; the external grounding of the shielded chassis is achieved by installing grounding bolts and connecting to the rack through the grounding bolts.

9. The aircraft brake fan motor controller according to claim 1, characterized in that: The power harness in the power component module adopts a single-point grounding method, and the shielding layer is crimped 360° at the connector interface.

10. The aircraft brake fan motor controller according to claim 9, characterized in that: The power ground is divided into digital ground and analog ground in the PCB. The analog ground and digital ground are connected at a single point inside, and the digital ground is insulated from the shielding box, while the analog ground is connected to the shielding box in a multi-point manner.

Images