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

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 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 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 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 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 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 discloses a non-sinusoidal random SVPWM modulation method for a five-phase inverter, belonging to the technical field of multi-phase motor drive control. The present invention selects two large vectors and two medium vectors surrounding the sector to which the fundamental wave reference voltage vector belongs to synthesize the fundamental wave reference voltage vector; The voltage vector synthesizes the third harmonic reference voltage vector; when calculating the vector action time, in each sampling period, keep the sampling period unchanged, randomly delay the PWM pulse and randomly assign two zero vector action times to achieve switching frequency and zero Double randomization of vector action times. The method disclosed in the present invention can linearly superimpose the torque components generated by the fundamental wave current and the third harmonic current when driving the motor, thereby increasing the torque density of the system, and greatly reducing the high The amplitude of the sub-harmonic wave can suppress electromagnetic interference and high-frequency noise, and improve the electromagnetic compatibility of the system.

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 discloses a method for improving harmonics of an inverter in a power generation system. The wind speed / light energy is converted into the output power of the inverter, and then the output power is divided according to the change curve of the total harmonic distortion (THD) with the output power. For several power level intervals, each power level interval corresponds to a switching frequency so that the THD is lower than 5%. When the wind power / photovoltaic power generation system is in operation throughout the year, a corresponding switching frequency is used for the power level interval where the output power is located. , In this way, the changing switching frequency is adapted to the changing output power to achieve the purpose of improving harmonics.