41results about How to "Increase the carrier frequency" patented technology

In a power conversion device that includes a PWM converting means for generating a PWM pulse by comparing three-phase voltage commands with a triangular wave carrier signal, a power converter for converting between a DC voltage and a three-phase AC voltage by driving a switching element according to the PWM pulse, a current detecting means for detecting a pulsed current flowing through a DC bus conductor of a main circuit, and a voltage command correcting means for correcting three-phase voltage commands, which corrects the three-phase voltage commands so that a line voltage value between the maximum phase and an intermediate phase and a line voltage value between the intermediate phase and the minimum phase are each equal to or larger than a predetermined value, the maximum phase, intermediate phase, and minimum phase being determined in correspondence to momentary values of the three-phase voltage commands arranged in descending order, if the voltage command is outside an allowable upper limit or lower limit, not only the voltage command for the maximum phase and / or the minimum phase but also the voltage command for the intermediate phase are corrected.Accordingly, the inability to detect a current due to a restriction imposed by an upper limit or a lower limit for an output voltage is eliminated, and highly precise control of the power conversion device is achieved independently of the situation.

A controller controls switching of IGBT devices of an inverter according to the desired output of the permanent magnet motor. The controller includes: a magnet temperature detection device that detects the magnet temperature of the permanent magnet motor based on the output of a temperature sensor; a setting device that sets a threshold value of the magnet temperature corresponding to the desired output of the permanent magnet motor, based on a predetermined relation between the output from the permanent magnet motor and a critical temperature, up to which demagnetization in the permanent magnet motor is not caused; and a carrier frequency control device that, when the magnet temperature detected by the magnet temperature detection device exceeds the threshold value, changes the carrier frequency, at which the IGBT devices are switched, such that a ripple current superimposed on a motor current that flows through the permanent magnet motor is reduced.

The invention discloses an SDR-based agile multi-mode multi-channel transceiver. The SDR-based agile multi-mode multi-channel transceiver includes a host computer, a display unit, a PCI bus data transceiver unit, an FPGA digital signal generation and reception demodulation analysis module, and an agile multi-mode multi-channel transceiver module. Among them, the FPGA digital signal generation and reception demodulation analysis module is used to realize multi-mode and multi-style signal generation and reception demodulation analysis functions, and the agile multi-mode multi-channel transceiver module is used to realize multi-signal mode and multi-communication style signal multi-channel RF transceiver function. The device in the present invention can support wireless communication signal sending and receiving scenarios such as general-purpose software-defined radio applications, MIMO radio, and wireless communication base stations, and has high integration, high consistency, high carrier frequency and bandwidth, multiple signal communication styles, and multiple signal formats. Support multi-input multi-output and other advantages.

The invention belongs to the field of protection of a new system for spaceflight measurement and control, and relates to a laser unified measurement and control method. High-speed data transmission, remote control and telemetering, distance measurement and speed measurement, and time-frequency transmission are achieved by using a laser link, the laser unified measurement and control method comprises a laser link transmission frame format design for implementing a new measurement and control system, and based on the distance, speed and clock difference measurement of a two-way laser communication link, transmission frame capture and "measurement frame" identification, a "measurement frame" arrival time is accurately measured. Therefore, by adoption of the laser unified measurement and control method provided by the invention, high-speed data transmission, remote control and telemetering, high-precision distance measurement and speed measurement, and time-frequency transmission can be achieved by using two-way laser link integration, the information transmission rate, the measurement rail precision, the time-frequency transmission precision and the anti-interception / anti-interferenceability of a spaceflight measurement and control system can be greatly improved, and the volume, the weight and the power consumption of a satellite borne terminal is greatly reduced, so that the laser unified measurement and control method has a broad application prospect.

The present invention includes method and apparatus for converting optical signals to MWOF signals for transmission to wireless data, audio and / or video terminals in the W-band. Advantageously, there is no need to maintain expensive and complex remote stations because a centralized station performs all the complex processing.

The invention provides an SVPWM modulation method, device and system. The SVPWM modulation method comprises the following steps: judging a sector where a voltage vector of a three-phase motor is located by adopting voltages Ualpha_n and Ubeta_n, wherein the voltages Ualpha_n and Ubeta_n are obtained by performing per-unit processing on voltages U<alpha> and U<beta> in a two-phase static coordinatesystem through a bus voltage; judging the action time of each phase of the voltage vector in each sector through the voltage Ualpha_n and the voltage Ubeta_n; and calculating the duty ratio of each phase of the voltage vector in PWM according to the action time of each phase of the voltage vector to obtain a PWM wave for controlling the three-phase motor. According to the SVPWM modulation methodprovided by the invention, the on-time of each phase in the three-phase PWM wave can be directly calculated, there is no need to calculate the on-time Tk and T<k+1> corresponding to two adjacent basicvectors Vk and V<k+1> and the switching time T0 corresponding to a zero vector in the sector region and then carry out time distribution and reconstruction, and therefore, the operation time of the SVPWM algorithm is greatly reduced.

The invention relates to a digital-to-analog converter, in particular to a double-edge triggering high-speed digital-to-analog converter, belonging to the field of integrated circuits. The double-edge triggering high-speed digital-to-analog converter comprises a clock circuit, a data multiplexer, a gating unit and a current helm unit. The clock circuit is used for generating clock signals; the data multiplexer is used for converting each path of input data into two paths of complementary data; the gating unit is used for carrying out logic operation on the data generated by the data multiplexer and the clock signals to generate control signals; and the current helm unit has an input end connected with the gating unit and is used for receiving control signals and outputting differential current analog signals. Compared with the traditional single-edge triggering DAC Digital-to-Analog Converter), the double-edge triggering DAC sends out data half an hour before or after the DAC conversion clock so as to convert data twice in a clock period, and can obtain twice effective sampling rate of the traditional single-edge triggering DAC at the same clock rate so as to provide users with wider signal bandwidth or higher carrier frequency.

The invention belongs to the field of air conditioner power supply circuits, particularly relates to an air conditioner emergency ventilation power supply circuit system, and solves the problems thatan air conditioner emergency ventilation power supply has no real-time display fault window, is low in adjustability, does not have fault self-diagnosis and self-repair capabilities, is poor in faultstorage and analysis and is low in fan load damping adaptability, and that the output voltage is greatly influenced by the input voltage, the output wind power is unstable and the like. The air conditioner emergency ventilation power supply circuit system comprises a control module, an input module, an output module and a boosting module, the control module comprises a DSP micro control panel andan I / O driving board, and pins are arranged on the I / O driving board and are connected with sensors. A power supply of the invention is convenient for observing the operation condition of the air conditioner emergency ventilation power supply and adjusting the output voltage and frequency, convenient for diagnosing, analyzing, processing and storing faults, and convenient for adapting to change offan load damping and input voltage. The power supply circuit system is suitable for emergency power supply of the train air conditioner emergency ventilation power supply.

This electromagnetic switching-valve position detection system is provided with: a current control circuit that obtains a smoothed direct current by smoothing a current from a power source via a rectifier bridge diode and a primary-side smoothing capacitor, that transmits the direct current to the secondary side by a switching transformer as an alternating current of pulse waves from a switching element where switching is controlled in accordance with a pulse signal from a pulse signal generation device, and that outputs same as a direct current that has been smoothed via a secondary-side diode and a secondary-side capacitor; a carrier wave generation device for superimposing high-frequency carrier waves for position detection onto signal waves of a current command; and a detection unit for extracting a frequency component of the carrier waves from a voltage feedback signal of a solenoid, and detecting a voltage amplitude thereof to obtain an amplitude signal. A control unit further comprises: a position determination unit for determining a valve spool position on the basis of the amplitude signal and preset criterion reference values corresponding to respective valve spool positions, and outputting a determination signal; and a determination circuit for outputting a valve position signal on the basis of the determination signal.

The invention relates to the technical field of mobile communication, and discloses a tunnel leaky cable communication system, that is, a main unit device that outputs a multi-channel intermediate frequency modulation signal in the source part, and then uses the leaky cable to transmit the intermediate frequency modulation signal and radiates to Space in the tunnel, and then use the vehicle-mounted relay unit equipment placed on the car body of the train running in the tunnel to convert the intermediate frequency modulation signal into a multi-channel radio frequency carrier signal at a target operating frequency higher than the cut-off frequency of the leaky cable, covering To the interior of the carriage, not only does it not need to redeploy new leaky cables that support higher cut-off frequencies, it greatly reduces the deployment cost, construction cost and difficulty of leaky cable coverage solutions for mobile communication signals with higher carrier frequencies (especially 5G signals), and supports Multi-channel communication; on the other hand, the system synchronization and equipment management of the on-board relay unit equipment are carried out by using cooperative base stations, which ensures the robustness of the on-board relay unit equipment.

The present invention provides a ground user navigation and positioning method based on the Beidou Ka inter-satellite link signal, comprising the following steps: (1) assuming that between k-1 and k two epochs, where k=1,2,3, ..., users equipped with Beidou inter-satellite link signal receiving terminals in a certain area on the ground generate inter-satellite link one-way ranging values ​​with N different Beidou satellites at different times, thereby obtaining N ranging equations; (2) using the receiving The machine clock model and inertial navigation information will uniformly reduce the user position in the ranging equation to T k (3) On the basis of realizing the time synchronization of the ranging value, ground users use the Kalman filter positioning algorithm to estimate their position in real time. The invention can avoid the interference source and deception source for the L-band navigation signal, compensate the usability problem caused by the failure of the L-band navigation signal to a certain extent, and ensure the navigation safety of key areas in special scenarios.

The invention provides a SVPWM modulation method, device and system. Wherein the SVPWM modulation method includes the steps: using the voltage U α_n , U β_n Determine the sector where the voltage vector of the three-phase motor is located, in which the voltage U in the two-phase stationary coordinate system is affected by the bus voltage α , U β Perform per unitization to get the voltage U α_n , U β_n ;Through the voltage U α_n , U β_n , determine the action time of each phase of the voltage vector in each sector; calculate the duty cycle of each phase of the voltage vector in PWM according to the action time of each phase of the voltage vector, and obtain the PWM wave for controlling the three-phase motor. The SVPWM modulation method proposed by the present invention can directly calculate the conduction time of each phase in the three-phase PWM wave, without first calculating the conduction time Tk and Tk corresponding to the two adjacent basic vectors Vk and Vk+1 in the sector area. Tk+1 and the switching time T0 corresponding to the zero vector, and then time allocation and reconstruction, greatly reduce the running time of the SVPWM algorithm.

The invention relates to a wide-band linear frequency modulation continuous millimeter-wave signal emitting source of a line patrol obstacle avoidance radar of an unmanned aerial vehicle. The output end of a constant temperature crystal oscillator is connected with a DDS reference signal source and a phase locked dielectric resonator oscillator, and the DDS reference signal source is connected with a control system; the DDS reference signal source is connected with a first filter, a phase locker, a low-pass filter, a voltage-controlled oscillator, a three-power distributor, a frequency multiplier, a first power amplifier and an antenna in sequence; the phase locked dielectric resonator oscillator is connected with a frequency mixer, the output of the frequency mixer is divided into two passages, and one passage is connected with a second filter, a first amplifier and the phase locker; the other passage is connected with the three-power distributor; the three-power distributor is further connected with a receiver to perform equal-energy power distribution; the frequency multiplier multiplies the received signal into 8-millimeter wave band signal, and the signal is emitted through the antenna after being amplified. The wide-band linear frequency modulation continuous millimeter-wave signal emitting source of the line patrol obstacle avoidance radar of the unmanned aerial vehicle is mainly used for a line patrol system of the unmanned aerial vehicle for a power transmission line, is capable of realizing the obstacle avoidance detection (the obstacle comprises a tower, the power transmission line and so on) for the unmanned aerial vehicle, and enables the detection target distance resolution ratio to be improved.

The invention discloses a method for keeping a reverse logic channel consistent, comprising the following steps of: transmitting a corresponding relationship of a reverse channel allocated for an AN (Access Network) and the reverse logic channel to a target AN by a source AN when an access terminal (AT) accesses among ANs and allocating a corresponding reverse logic channel for a newly-added reverse channel according to the corresponding relationship of the received reverse channel and the reverse logic channel when the newly-added reverse channel exists in the target AN. The invention also discloses a system for keeping the reverse logic channel consistent, which ensures that information of the reverse logic channel in the target AN keeps consistent with that of the source AN during AN switch, thereby ensuring that the reverse logic channel allocated by the target AN for newly-added reverse channel cannot be conflicted with the allocated reverse logic channel.

The invention provides a method and a device for generating X-frequency band one-way ranging signals for deep space exploration. The method provided by the invention can generate one-way ranging sidetone signals in the X-frequency band. The device provided by the invention comprises simulation devices such as a crystal oscillator, a frequency divider, a low-pass filter, a frequency multiplier, a phase shifter and the like, and turn-off of DOR (Differential One-way Ranging) sidetone signals can be controlled through an instruction. The crystal oscillator generates initial reference signals, one path of the initial reference signals are inputted into the frequency multiplier after power division, the frequency multiplier generates X-frequency band carriers, another path of the initial reference signals are inputted into a divide-by-two frequency divider, a left path of the initial reference signals are inputted into a divide-by-ten frequency divider, and two paths of DOR sidetone signals are generated respectively. Phase modulation is carried out on the two paths of DOR sidetone signals in the X-frequency band, and the two paths of DOR sidetone signals are outputted after being amplified and isolated. Divide-by-two frequency division and divide-by-ten frequency division are completed by a decimal counter. The X-frequency band one-way ranging signals generated by using the method provided by the invention can complete a function of accurate ranging for a deep space probe by being matched with relevant ground station equipment, thereby being applicable to the fields of lunar exploration, Mars exploration and the like.