30results about How to "No need to change the topology" patented technology

The invention belongs to the technical field of motor control, and relates to a commutation torque ripple suppression method for a permanent magnet brushless DC motor. The method comprises the following steps of: detecting a rising edge or falling edge of a Hall signal, starting commutation, and executing the commutation torque ripple suppression method; acquiring a non-commutation current sampling value and a motor running speed at a current moment; calculating back electromotive forces of phases of a three-phase winding at the next moment according to the motor running speed and a commutation mode respectively; obtaining the voltages to power earth of end points of the three-phase winding in different inverter circuit switching-on states at the next moment respectively; predicting predicted values of non-commutation current in the different inverter circuit switching-on states at the next moment respectively; performing estimation on the predicted values of the non-commutation current in the different inverter circuit switching-on states by utilizing a value function; selecting the inverter circuit switching-on state in which the value function has the smallest value as the inverter circuit switching-on state of the next moment, and generating a corresponding inverter circuit control signal; and detecting the current of a corresponding switched-off phase is reduced to zero, finishing the commutation process, and stopping the commutation torque ripple suppression method. By the method, the commutation process can be accurately determined, and control over the inverter circuit switching-on state can be realized relatively better at the moment of commutation to realize commutation torque ripple suppression.

The invention discloses a five-phase inverter random SVPWM modulation method, and belongs to the technical field of multi-phase inverter drive control. In every sampling cycle, the sampling cycle is kept constant, a PWM pulse is delayed randomly, to achieve random change of a switch cycle, at the same time, two vector action time obtained through an NFV-SVPWM algorithm are randomly allocated, and double-random of switch frequency and zero vector action time is achieved. According to the five-phase random SVPWM modulation method, on the condition of not influencing low frequency-band harmonic performance, the amplitude of higher harmonic is drastically lowered, harmonic originally concentrated on the switch frequency and around the integral multiple switch frequency is dispersed into a wider frequency spectrum range, thus a more consecutive and even frequency spectrum is obtained, electromagnetic interference and high frequency noise are effectively inhibited, and the electromagnetic compatibility of the system is improved.

The invention discloses a cascaded converter-based multifunctional high-speed switch device which structurally comprises a main switch module, an auxiliary switch K1, an auxiliary switch K2 and an auxiliary switch K3; the main switch module is connected with a power source by the auxiliary switch K1 and is connected with a load by the auxiliary switch K3, and the main switch module is connected with the auxiliary switch K1 and the auxiliary switch K3 with each other in series and is connected with the auxiliary switch K2 in parallel with each other; and the main switch module comprises a cascaded H bridge converter and a wave filtering link, an output end of the cascaded H bridge converter is connected with the wave filtering link, and the cascaded H bridge converter comprises n H bridge converter cascaded units which are connected with one another in series. The cascaded converter-based multifunctional high-speed switch device is flexibly applicable to various connection modes between the power source and the load, has various functions of superspeed switching, voltage compensating, fault current limiting and the like, and is applicable to the middle and high voltage occasion due to a cascaded structure.

The invention discloses a hybrid modular multilevel converter-based topology structure and a deicing device. With a three-phase hybrid modular multilevel converter as a main circuit, each phase is formed by mixing cascaded half-bridge sub-modules and full-bridge sub-modules; and the quantity ratio of the half-bridge sub-modules to the full-bridge sub-modules in each phase is 1 to 1. Output voltage of a direct-current bus of the hybrid modular multilevel converter disclosed by the invention can be continuously adjustable from zero to the maximum value; when the topology structure is used as the direct-current deicing device, a flexible and effective control on direct-current deicing current can be achieved to meet the deicing requirements of different lines. In addition, the topology structure can also be used as an STATCOM; and power switching devices can be saved by 25%.

The invention discloses a five-phase inverter non-sinusoidal random SVPWM modulation method, and belongs to the technical field of multi-phase motor drive control. According to the method, two big vectors and two middle vectors which surround sectors which a fundamental wave reference voltage vector belongs to are selected to compound the fundamental wave reference voltage vector; a third harmonic reference voltage vector is compounded on a voltage vector corresponding to a third harmonic space through the chosen two big vectors and two middle vectors; when vector action time is calculated, in every sampling cycle, the sampling cycle is kept constant, a PWM pulse is delayed randomly, two zero action times are randomly allocated, and double-random of switch frequency and zero vector action time is achieved. According to the five-phase inverter non-sinusoidal random SVPWM modulation method, when a motor is driven, the torque amount of a fundamental wave current and a third harmonic current are linearly overlaid, thus the torque density of a system is increased, on the condition of not influencing low frequency-band harmonic performance, the amplitude of higher harmonic is drastically lowered, electromagnetic interference and high frequency noise are inhibited, and the electromagnetic compatibility of the system is improved.

The invention discloses a PWM (Pulse Width Modulation) method for suppressing commutation torque ripples of a brushless DC motor, which relates to a DC power supply, a brushless DC motor, a three-phase inverter bridge and a controller, and is characterized in that corresponding PWM measures are adopted to suppress commutation torque ripples through determining a rotating speed range and a commutation stage of the brushless DC motor, and the commutation time of the brushless DC motor is shortened at the same time; and the commutation time has greatly improvements on methods of position-sensorless control and back electromotive force zero-crossing point detection of the brushless DC motor, so that the smooth running performance of the brushless DC motor can be improved at the same time. Commutation torque ripples of the brushless DC motor in the whole speed range are effectively suppressed through selecting an optimal PWM mode in the commutation stage on the basis of PWM modes, the commutation time is shortened at the same time, the control is simple, the implementation is easy, and the smooth running performance of the brushless DC motor is improved. The method provided by the invention does not need to change a topological structure and can be used by slightly changing a software part, and the cost of a hardware system is not increased.

The invention discloses a method for suppressing the commutation torque ripples of a brushless DC motor. The invention relates to the technical field of control technology of brushless DC motors. The method includes the following steps: after entering a break off, conducting upper bridge commutation based on the formula: (as shown in the description) to resolve cycle count of advanced commutation; conducting lower bridge commutation based on the formula (as shown in the description) to resolve cycles of advanced commutation; the PWM cycle count n1 during the ongoing period of the previous Hall signal; the PWM cycle count n2 during the ongoing period of the current Hall signal; when n1-n2 is greater than n upper or n lower, conducting no commutation, and when n1-n2 is not greater than n upper or n lower, conducting commutation: an upper bridge-non-commutation phase duty cycle staying at 1, changing an on-phase duty cycle from 0 to a duty cycle d of an off-phase duty cycle prior to the commutation, the off-phase duty cycle being changed to doff; a lower bridge-non-commutation phase duty cycle staying at d, changing the on-phase duty cycle from 0 to the duty cycle 1 of the off-phase prior to the commutation, the off-phase duty cycle being changed to doff. According to the invention, the method can be applied to a wide range of rotation speeds and load changes and has high electric output power.

The invention discloses a DNP (Distributed Network Protocol) communication access control method based on a neural network. A feature sequence is established by extracting destination addresses, source addresses, directions, primary state flag bits and application layer function codes in a DNP3.0 protocol; the feature sequence is learned by using the neural network, thus obtaining a detection model for access control; a captured data packet is preprocessed, thus obtaining a to-be-detected sequence; and after the to-be-detected sequence is detected by the detection model, whether the data packet is allowed to pass or not is judged, thus finishing DNP3.0 communication access control.

The invention discloses an IEC 60870-5-104 communication access control method. The method comprises the following steps: extracting the first bit of a control field first octet, the second bit of the control field first octet, and the first bit of the control field third octet which are in an IEC 60870-5-104 protocol, a type identifier and a transmission reason as features, learning a specific combination of above features by use of a neural network, thereby obtaining a standard matching rule for access control; and then preprocessing a captured data packet to obtain a to-be-detected sequence, matching the obtained sequence with the standard matching rule to judge whether the data packet is allowed to pass, thereby finishing the IEC 60870-5-104 communication access control.

The invention relates to a data transmission method and system based on intelligent substation clock synchronization. The method includes the following steps: analyzing a message type corresponding toa data stream according to a transmission mode of the data stream; and assigning an output priority to the data stream according to the message type, and mapping the data stream to an output queue ofa corresponding switch for transmission. According to the data transmission method and system based on intelligent substation clock synchronization provided by the invention, through the steps of analyzing the message type corresponding to the data stream according to the transmission mode of the data stream, assigning the output priority to the data stream according to the message type, and mapping the data stream to the output queue of the corresponding switch for transmission, PDEelay_Rep and PDEelay_Resp messages can be preferentially forwarded even if the messages are in a network congestion state, the bidirectional path delay is basically the same, and the final time synchronization accuracy can be greatly improved.

The invention discloses a variable air gap disc-shaped linear induction traction motor high-speed mutual feedback table for track traffic. The device comprises a disc-shaped secondary device, a linear induction motor primary device, a rotary induction motor, a No.1 converter, a No.2 converter, an umbrella-shaped coupler, a primary base, a secondary support table, a rotary coder, a torque meter and a fly wheel. The linear induction motor primary device is fixed on the primary base; the disc-shaped secondary device is rigidly linked with a shaft penetrating through the disc-shaped secondary device; the secondary support table is linked with the shaft by a bearing; the rotary coder is linked with a shaft penetrating through the rotary coder by a bearing; the umbrella-shaped coupler, the fly wheel, the torque meter and the rotary induction motor are serially connected together by a connection shaft in sequence. The No.2 converter is connected with the rotary induction motor; the No.2 converter is connected with the linear induction motor primary device. The variable air gap disc-shaped linear induction traction motor high-speed mutual feedback table for the track traffic has the characteristics of air gap adjusting function, energy saving, comprehensive test on electromagnetic force and work condition, capability of test on high-speed work condition, small size, less space occupation, suitability for indoor use and the like.

The invention discloses a cascaded converter-based multifunctional high-speed switch device which structurally comprises a main switch module, an auxiliary switch K1, an auxiliary switch K2 and an auxiliary switch K3; the main switch module is connected with a power source by the auxiliary switch K1 and is connected with a load by the auxiliary switch K3, and the main switch module is connected with the auxiliary switch K1 and the auxiliary switch K3 with each other in series and is connected with the auxiliary switch K2 in parallel with each other; and the main switch module comprises a cascaded H bridge converter and a wave filtering link, an output end of the cascaded H bridge converter is connected with the wave filtering link, and the cascaded H bridge converter comprises n H bridge converter cascaded units which are connected with one another in series. The cascaded converter-based multifunctional high-speed switch device is flexibly applicable to various connection modes between the power source and the load, has various functions of superspeed switching, voltage compensating, fault current limiting and the like, and is applicable to the middle and high voltage occasion due to a cascaded structure.

The invention provides a magnetically levitated train model demonstrating and testing device. The magnetically levitated train model demonstrating and testing device comprises a U-shaped track, two rollers and a base; two rotary motors, two frequency converters, a speed coder and a display are respectively installed on the base; the axes of the two rollers are vertical to the base, and respectively connected with the two rotary motors through rotating shafts; the U-shaped track is fixed on the base; a displacement sensor and a three-dimensional force sensor are installed on the base between the U-shaped track; the two rollers are symmetrical by taking the U-shaped track as the centre; the upper and lower sides of the outside surfaces of the two rollers are each installed with an annular copper plate; each rotary motor is in circuit connection with a frequency converter, and then, connected to the speed coder and the display; and the displacement sensor and the three-dimensional force sensor are connected to the display through the circuit. The device can detect the three-dimensional force, the running speed and the suspension height of a magnetically levitated model directly and accurately; and thus, whether a magnetically levitated train model achieves the design standard or not can be judged.

The disclosure relates to technology for supporting multiple flow management protocols in a virtual network switch and changing a flow management protocol without changing switch topology configurations at run time. A data plane provider is detected via a pluggable software module (or plugin or plugin module) that identifies and controls the data plane provider with network interfaces and enablesflow management protocols. A switch topology is then constructed by creating a virtual switch object, adding ports to the virtual switch object. A datapath is then created using the switch topology and the first flow management protocol on the data plane provider. Network interfaces are connect to each ports respectively to enable communication among the entities attached to each network interfaceaccording to the first flow management protocol. The datapath can be later changed to use the second flow management protocol and retain the same topology at run time.

The application discloses a bus network management method, a bus network management system and a vehicle. Wherein the bus network includes a CAN node and a CAN FD node, the method includes: when it is determined that the CAN FD node has a CAN FD network communication requirement, the CAN FD node controls the CAN node to enter the sleep mode based on the mode of stopping sending network management messages, and controls the CAN FD node to enter CANFD communication status; when it is determined that the CANFD node has no CANFD network communication requirements and has CAN network communication requirements, the CANFD node starts to send network management messages; when the CAN node receives the network management messages sent by the CANFD node, it wakes up and enters CAN communication status. The method can solve the problem in the prior art that CAN nodes and CAN FD nodes coexist in nodes on a bus network.

The invention discloses a PWM (Pulse Width Modulation) method for suppressing commutation torque ripples of a brushless DC motor, which relates to a DC power supply, a brushless DC motor, a three-phase inverter bridge and a controller, and is characterized in that corresponding PWM measures are adopted to suppress commutation torque ripples through determining a rotating speed range and a commutation stage of the brushless DC motor, and the commutation time of the brushless DC motor is shortened at the same time; and the commutation time has greatly improvements on methods of position-sensorless control and back electromotive force zero-crossing point detection of the brushless DC motor, so that the smooth running performance of the brushless DC motor can be improved at the same time. Commutation torque ripples of the brushless DC motor in the whole speed range are effectively suppressed through selecting an optimal PWM mode in the commutation stage on the basis of PWM modes, the commutation time is shortened at the same time, the control is simple, the implementation is easy, and the smooth running performance of the brushless DC motor is improved. The method provided by the invention does not need to change a topological structure and can be used by slightly changing a software part, and the cost of a hardware system is not increased.

The invention discloses a method for optimizing the loss of a modular multilevel converter under fault-tolerant control, which includes the following steps: S1. When a submodule fault occurs in any bridge arm of the modular multilevel converter during normal operation, the fault is removed The fault sub-module in the bridge arm realizes fault-tolerant control; S2, suppresses the base frequency circulation current through the base frequency circulation controller; S3, uses the loss expressions of different switching tubes of the modular multilevel converter sub-module to calculate the fault bridge respectively The loss of each sub-module in the normal bridge arm and the normal bridge arm; S4. For the unbalanced loss between the bridge arms of the modular multilevel converter, the normal bridge arm sub-module loss is used as a reference value, and the capacitance voltage of the faulty bridge arm is adjusted to sort The control cycle realizes the loss control of the remaining sub-modules of the faulty bridge arm, and finally realizes the loss balance of each sub-module of the faulty bridge arm and the normal bridge arm. Compared with the conventional method, the invention does not need to increase the construction cost of the modularized multilevel converter.

The invention discloses an intrusion detection method based on the MQTT protocol, which comprises the steps of capturing the MQTT data packet at port 1883 by using the Netfilter framework of Linux between the main station and the sub-station; extracting the first byte of the fixed header of the MQTT data packet Control message type value x 1 , the value x of the flag bit specifying the control packet type in the first byte of the fixed header 2 , the value x of the second byte of the fixed header 3 ; Extract the x from the MQTT packet 1 、x 2 and x 3 Combined into a set of data, the format of the data is X n =(x 1 , x 2 , x 3 ); the data is transmitted as an input to the neural network model to obtain a detection result; when the detection result is greater than a preset threshold, it indicates that the MQTT packet is a normal data packet, allowing it to pass; when the detection result is less than a preset threshold , indicating that the MQTT data packet is an abnormal data packet and is not allowed to pass.

The invention belongs to the technical field of motor control, and relates to a commutation torque ripple suppression method for a permanent magnet brushless DC motor. The method comprises the following steps of: detecting a rising edge or falling edge of a Hall signal, starting commutation, and executing the commutation torque ripple suppression method; acquiring a non-commutation current sampling value and a motor running speed at a current moment; calculating back electromotive forces of phases of a three-phase winding at the next moment according to the motor running speed and a commutation mode respectively; obtaining the voltages to power earth of end points of the three-phase winding in different inverter circuit switching-on states at the next moment respectively; predicting predicted values of non-commutation current in the different inverter circuit switching-on states at the next moment respectively; performing estimation on the predicted values of the non-commutation current in the different inverter circuit switching-on states by utilizing a value function; selecting the inverter circuit switching-on state in which the value function has the smallest value as the inverter circuit switching-on state of the next moment, and generating a corresponding inverter circuit control signal; and detecting the current of a corresponding switched-off phase is reduced to zero, finishing the commutation process, and stopping the commutation torque ripple suppression method. By the method, the commutation process can be accurately determined, and control over the inverter circuit switching-on state can be realized relatively better at the moment of commutation to realize commutation torque ripple suppression.

The invention discloses a method for suppressing the commutation torque ripples of a brushless DC motor. The invention relates to the technical field of control technology of brushless DC motors. The method includes the following steps: after entering a break off, conducting upper bridge commutation based on the formula: (as shown in the description) to resolve cycle count of advanced commutation; conducting lower bridge commutation based on the formula (as shown in the description) to resolve cycles of advanced commutation; the PWM cycle count n1 during the ongoing period of the previous Hall signal; the PWM cycle count n2 during the ongoing period of the current Hall signal; when n1-n2 is greater than n upper or n lower, conducting no commutation, and when n1-n2 is not greater than n upper or n lower, conducting commutation: an upper bridge-non-commutation phase duty cycle staying at 1, changing an on-phase duty cycle from 0 to a duty cycle d of an off-phase duty cycle prior to the commutation, the off-phase duty cycle being changed to doff; a lower bridge-non-commutation phase duty cycle staying at d, changing the on-phase duty cycle from 0 to the duty cycle 1 of the off-phase prior to the commutation, the off-phase duty cycle being changed to doff. According to the invention, the method can be applied to a wide range of rotation speeds and load changes and has high electric output power.

The invention proposes a harmonic suppression method for the output voltage of a cascaded electric energy management device, which belongs to the technical field of power electronic device control and is applied to a cascaded electric energy management device. After the outlet of the cascaded power management device is stepped down, it directly supplies power to the load; in order to suppress the harmonics of the output voltage of the cascaded power management device, especially the harmonics under nonlinear loads, a resonance regulator is connected in parallel with the traditional PI regulator. regulator, in which the resonant regulator is dynamically changed according to the harmonic content of the output current monitored in real time. The method can effectively suppress the harmonic content of the output voltage, and the control method is simple, without changing the topology of the existing circuit, only needing to add a corresponding circuit, which is easy for engineering implementation.

The invention provides a flow mirroring system and method realized by hardware and based on an EtherCAT network, and aims to realize undisturbed replication of network flow. According to the method, link layer data in a standard Ethernet model is shunted, and then different processing flows are respectively executed on the two paths of the link layer data, so that the abnormal flow in the networkis monitored while the normal communication requirement of an industrial control system is met. The method is achieved through hardware, the mirroring efficiency is high, processing resources of network communication equipment are not occupied, and the situation that normal communication of the industrial control network is affected by flow mirroring can be effectively avoided; an EtherCAT networkflow undisturbed interception device can be used as a slave station to be directly accessed to a standard EtherCAT network without changing the topological structure of the standard EtherCAT network;compared with a port mirroring mode based on a switch, the number of used ports is reduced, the bandwidth of mirroring ports is not limited, a flow undisturbed interception device does not need to carry out complex configuration operation, and the complexity of flow replication is simplified.

The invention discloses a five-phase inverter random SVPWM modulation method, belonging to the technical field of multi-phase inverter drive control. In each sampling period, the sampling period is kept constant, and the PWM pulse is randomly delayed to realize the randomization of the switching period. Double randomization of vector action times. The modulation method of the present invention can greatly reduce the amplitude of high-order harmonics without affecting the performance of low-frequency harmonics, and disperse the harmonics originally concentrated around the switching frequency and its integer multiples into a wider spectrum range , so as to obtain a more continuous and uniform frequency spectrum, effectively suppress electromagnetic interference and high-frequency noise, and improve the electromagnetic compatibility of the system.

The invention discloses a bus network management method, a bus network management system and a vehicle. The bus network comprises a CAN node and a CANFD node, and the method comprises the steps that when it is determined that the CANFD node has a CANFD network communication requirement, the CANFD node controls the CAN node to enter a sleep mode and controls the CANFD node to enter a CANFD communication state based on a mode of stopping sending a network management message; when it is determined that the CANFD node does not have the CANFD network communication requirement and has the CAN network communication requirement, the CANFD node starts to send a network management message; and when receiving the network management message sent by the CANFD node, the CAN node is awakened and enters aCAN communication state. The method can solve the problem that the coexistence of the CAN node and the CANFD node of the node on the bus network cannot be realized in the prior art.

The invention discloses a neural network-based DNP communication access control method, which constructs a feature sequence by extracting the destination address, source address, direction bit, source station flag and application layer function code in the DNP3.0 protocol, and utilizes the neural network Learn the above feature sequence to obtain the detection model of access control; then preprocess the captured data packets to obtain the sequence to be detected, after the sequence to be detected passes the detection of the detection model, it is judged whether the data packet is allowed to pass, thus completing DNP3. 0 communication access control.

The invention provides a device for demonstrating and testing a maglev train model, comprising: a U-shaped track, two rollers and a base; two rotating motors, two frequency converters, a speed encoder and a display are respectively installed on the base; The axes of the two rollers are perpendicular to the base, and are respectively connected to the two rotating motors through the rotating shaft; the U-shaped track is fixed on the base, and displacement sensors and three-dimensional force sensors are installed on the base between the U-shaped tracks. The type track is centrally symmetrical; the upper and lower sides of the outer surfaces of the two rollers are respectively equipped with annular copper plates; each rotating motor circuit is connected to a frequency converter, and then connected to the speed encoder and display, and the displacement sensor and the three-dimensional force sensor are connected through the circuit to the display. The device can directly and accurately detect the three-dimensional force, running speed and levitation height of the maglev model, so as to judge whether the maglev train model meets the design standard.

The invention proposes a reactive power control method for a direct-drive fan system when the grid voltage drops asymmetrically, which calculates the maximum output power of the wind turbine according to the wind speed Pmmax ; Calculate the positive and negative sequence dq-axis components when the grid voltage drops asymmetrically, determine the reactive power of the direct-drive fan system according to the requirements of voltage and reactive power control, and calculate the reactive current reference value of the grid-side converter; Calculate the active current reference value of the grid-side converter according to the maximum output power of the generator and the grid-side reactive current reference value; calculate the active power reference value of the grid-side converter according to the current reference value of the grid-side converter, The reference value controls the rotational speed of the wind turbine so that it operates in the stable operating region of the wind turbine torque-speed characteristic curve. This direct-drive fan system control method can make full use of the reactive power regulation capability of the fan system when the grid voltage drops asymmetrically, and at the same time eliminates the double-frequency fluctuation of the DC side capacitor voltage, realizes a balanced sinusoidal grid-connected current, and improves the system's performance. performance.