101 results about "Constant frequency" patented technology

The invention discloses a three-phase vehicle-mounted charger hierarchical control method and system based on a battery state, and the method comprises the steps: obtaining the battery state data of a vehicle-mounted power battery, the battery state data at least comprising a battery voltage and a battery charge state; determining a charging mode according to the battery voltage and / or the battery charge state; when the charging mode is a first charging mode, controlling the PFC converter to operate in a constant voltage output mode, and executing voltage following control on the bidirectional DC-DC converter based on the battery voltage; and when the charging mode is a second charging mode, executing voltage following control on the PFC converter based on the battery voltage, and controlling the bidirectional DC-DC converter to operate in a constant-frequency or constant-phase output mode at the same time. By setting hierarchical control strategies under different working conditions, the output voltage of the PFC converter is adaptively adjusted, the voltage regulation transformation ratio under different working conditions is optimized, the overall circuit structure is improved, and the charging efficiency of the vehicle-mounted charger within the full working condition range is improved.

The purpose of the present invention is to provide a magnetic resonance imaging apparatus and a method for controlling a refrigerator. The magnetic resonance imaging apparatus increases the operating rate of an MRI apparatus by prolonging the replacement life of the refrigerator and reducing the replacement frequency of the refrigerator. And executing a cold head life prolonging mode. In the cold head life extension mode, regardless of the temperature of the superconducting coil, the displacer of the refrigerator is moved at a constant frequency lower than a predetermined upper limit frequency, and the drive frequency of the compressor drive unit adjusted by the compressor inverter is controlled in accordance with the temperature of the superconducting coil.

The invention relates to a hydraulic station pressure closed-loop energy-saving control system and method.The hydraulic station pressure closed-loop energy-saving control system comprises a PID adjusting controller, a servo motor and a hydraulic pump, a control signal is input into the PID adjusting controller, the PID adjusting controller adjusts the servo motor according to feedback of speed and pressure signals, the adjusted signal is input into the servo motor, and the servo motor is controlled by the PID adjusting controller. The servo motor acts according to the adjusting signal and drives the hydraulic pump to output pressure. A constant-frequency asynchronous motor used at present is replaced by the servo motor, a servo driving system, a pressure feedback sensor and other assemblies are additionally arranged in a matched mode to form a servo variable-speed control system, pressure and flow form double-closed-loop control, on-demand energy supply of the hydraulic pump is achieved, power matching is optimized, and electric energy waste during low-flow work of the hydraulic station is reduced. According to the electro-hydraulic servo control system, pressure and speed double-closed-loop control is adopted, accurate energy supply according to needs is really achieved, shutdown operation can be achieved in the long-time pressure maintaining or intermittent stage, and therefore optimal energy supply is achieved.

This application provides a current limiting protection method and system for a variable speed constant frequency device. The method includes: First, the variable speed constant frequency device operates in a constant voltage state during normal operation; Second, it determines whether a hardware overcurrent protection event has occurred. If so, it proceeds to the third step; otherwise, it returns to the first step; Third, it performs a fault reset and automatically restarts the variable speed constant frequency device to operate in a constant current state. Furthermore, after operating in this constant current state, it determines whether the hardware overcurrent protection event is caused by a short circuit, overload, or other temporary sudden anomaly. If it is a short circuit, it maintains a preset current output for a certain duration, allowing the downstream circuit time to switch power and maintain circuit stability. If it is an overload, it performs overload protection and shuts down to prevent circuit damage. If it is neither a short circuit nor an overload, it is generally a temporary sudden anomaly, and it can switch back to operating in a constant voltage state.

The invention discloses a nonlinear support system and a hypersonic velocity sweep / fixed frequency wind tunnel test method, and belongs to the technical field of wind tunnel tests. The device comprises a protection platform, a protection cover, a lifting platform, a vertical mounting plate, a protection cover shoulder split, a test model and a driving mechanism, the test model is mounted at the top of the vertical mounting plate through the driving mechanism, the vertical mounting plate is mounted on the lifting platform, the protection cover is mounted on the protection platform, and the protection cover shoulder split is arranged at the top of the protection cover. The vertical mounting plate and the driving mechanism are arranged in the protective cover; and the test model at the top of the vertical mounting plate extends out of the protective cover shoulder cleft of the protective cover. The technical problem that in an existing hypersonic wind tunnel test, structural nonlinear factors such as gaps, friction and collision between kinematic pairs of an executing mechanism are ignored due to a simplified supporting mode, and consequently the influence of the performance of the executing mechanism in a complex vibration environment cannot be truly reflected by a test result is solved. And a reliable test means is provided for revealing a structural nonlinearity and pneumatic nonlinearity coupling effect rule.

The invention discloses a distributed architecture voltage frequency control method and a distributed architecture voltage frequency control system for a DRU-sent network construction energy storage new energy island. The island comprises a plurality of new energy stations, matched new energy storage stations and a DRU alternating current side energy storage station. Aiming at DRU side energy storage, on the basis of keeping active-frequency droop control, a reactive-voltage droop loop is replaced by a DC power-voltage control loop, and the DRU is controlled to send a power tracking scheduling instruction by adjusting an output voltage; for new energy side energy storage, active-frequency droop and reactive-voltage droop are adopted to construct a local voltage frequency, an active power compensation instruction distributed by a system-level constant-frequency control loop is received, a local active reference value is corrected, and system frequency indifference adjustment is realized. The method adapts to the specific power-voltage coupling characteristic of the DRU, the frequency can be kept stable when the new energy output fluctuates, the power is constantly sent out according to the scheduling instruction, and the operation reliability and schedulability of the island system are improved.

The application provides a half-controlled step frequency scanning variable scanning mode ultrasonic excitation signal generating device and method, and relates to the technical field of ultrasonic power supplies.The device structure comprises four parts of a power stage power conversion circuit, signal sampling and conditioning, a main controller and peripheral circuit, and a button and display circuit.The power stage power conversion circuit is composed of AC-DC conversion, power regulation, DC-AC inversion, impedance matching and series tuning modules.Through the program design of the main controller, different ultrasonic excitation signal frequency modes can be realized, including a constant frequency mode of keeping the center frequency, a constant scanning mode of constant step frequency scanning, and a variable scanning mode of half-controlled step frequency scanning.The variable scanning mode of half-controlled step frequency scanning provides a novel frequency excitation mode for ultrasonic auxiliary processing, is beneficial to the resonance of ultrasonic waves and complex material liquid, and helps to improve the acoustic-cavitation yield.

The application provides a power battery heating noise processing method and device and an electric vehicle, and relates to the field of noise control.The application comprises the following steps: receiving a power battery heating instruction, and generating a d-axis current instruction and a q-axis current instruction according to the power battery heating instruction; outputting a q-axis voltage through a PI controller according to the q-axis current instruction, so as to control the q-axis current with an output value of zero; controlling a d-axis voltage to be output through hysteresis control according to the d-axis current instruction; generating a random factor at a preset frequency, adjusting the amplitude of the d-axis voltage according to the random factor, randomly adjusting the current slope of the motor at each pulse current point, generating a random pulse current acting on the power battery, and making the noise generated in the battery heating process randomly distributed, so as to solve the problem that the existing power battery heating process using high-frequency constant-frequency alternating current generates high-frequency sharp and piercing noise.

By extending the lifespan of the refrigeration unit and reducing the frequency of replacement, the operating rate of the MRI system will be improved. [Solution] The cold head life extension mode is implemented. In the cold head life extension mode, the refrigerator's displayer is operated at a constant frequency lower than a predetermined upper frequency, regardless of the temperature of the superconducting coil, and the compressor inverter controls the drive frequency of the compressor drive unit according to the temperature of the superconducting coil.

The invention belongs to the technical field of aviation power generation systems, and discloses an alternating current starting power generation system starting phase sequence online identification method, which comprises the following steps of: 1, providing 28V control electricity and 115V / 400Hz three-phase constant-frequency alternating current for a generator controller; 2, setting a current comparison threshold value, wherein a data acquisition period is as follows; the starting generator controller is used for converting the 115V / 400Hz three-phase constant-frequency alternating current into low-voltage three-phase constant-frequency alternating current; 3, applying the low-voltage three-phase constant-frequency alternating current to a three-phase winding of a main generator stator to generate three-phase current; step 4, collecting three-phase current fed back by a current sensor, and recording the three-phase current as,..., and collecting three-phase current fed back by a motor mutual inductor, and recording the three-phase current as,...; 5, calculating the sum of the three-phase current according to the sum; and 6, calculating the absolute value of the current sum in one current period, solving the average value of the absolute values of continuous N periods, if the average value is smaller than a set threshold value, indicating that the starting phase sequence is correct, otherwise, indicating that the starting phase sequence is wrong.

A plasma processing system includes a chamber configured to house plasma in a process space; a wafer holder configured to place a structure in the chamber, wherein the structure is configured to be etched by the plasma; a first chamber component arranged on a first side of the wafer holder and is applied with a first signal; and a second chamber component arranged on a second side of the wafer holder and is applied with a second signal, the second side opposite to the first side. The first signal is associated with a first constant frequency, and the second signal is associated with a second constant frequency.

This invention relates to a method and apparatus for resolving velocity ambiguity based on constant frequency assistance. The method includes the following steps: a radar sequentially transmits a constant frequency band signal and a linear continuously modulated pulse train, and acquires the radar echo signal; both the constant frequency band echo signal and the sawtooth band echo signal are mixed to obtain a constant frequency band intermediate frequency signal and a sawtooth band intermediate frequency signal; the constant frequency band intermediate frequency signal is processed by a fast Fourier transform to obtain a target true velocity estimate; the sawtooth band intermediate frequency signal is sequentially processed by a two-dimensional fast Fourier transform, a two-dimensional constant false alarm rate (CFAR) processing, and a centroid condensation processing to obtain a target range velocity estimate; based on a velocity matching method using a Fourier rotation factor, the target true velocity estimate is matched with the target range velocity estimate to obtain the true velocity of all targets. This method not only resolves velocity ambiguity but also improves velocity accuracy, offering advantages such as high velocity measurement accuracy, high real-time performance, and simplicity.

The application discloses a network topology of AC power reconstruction at a receiving end of DC power transmission and belongs to the technical field of power generation and power equipment. The network topology comprises a DC / AC converter connected with a DC power transmission line and used for converting DC power inputted by the DC power transmission line into AC power with adjustable frequency, size and phase; and a synchronous motor-synchronous generator set, wherein the AC power outputted by the DC / AC converter is connected to a stator side of the synchronous motor, drives the synchronous motor and a synchronous generator coaxially connected with the synchronous motor to rotate, the DC / AC converter drives the synchronous motor-synchronous generator set to start from static to variable frequency, and after the synchronous motor-synchronous generator set is started, the constant frequency output of the DC / AC converter drives the synchronous motor-synchronous generator set to rotate at a constant speed, and the synchronous generator outputs constant frequency AC power to be connected to an AC power grid at the receiving end. The application fundamentally solves the problem of AC power stability reconstruction at the receiving end of the DC power transmission.

The invention discloses a new energy participated microgrid black start control method and device, a medium and a product, and relates to the field of power supply. After it is detected that the micro-grid system breaks down and enters the all-black state, whether the black start requirement is met or not is judged firstly; if yes, all loads in the micro-grid system are cut off to be in a no-load state; in a no-load state, each black-start power supply in the micro-grid system respectively adopts a constant-voltage / constant-frequency control mode to carry out on-load starting; after on-load starting and stable operation are completed, synchronous parallel networking of the black-start power supply is carried out; after stable operation, a non-black-start power supply in the micro-grid system is connected step by step, and residual loads are put into step by step; in the process, the operation state of the micro-grid is optimized in real time, all non-black-start power supplies are connected and all loads are input on the premise that the micro-grid system operates stably, and therefore the black-start process of the micro-grid can be smoothly completed with the participation of high-proportion new energy, and it is guaranteed that the system operates safely, stably and efficiently.

The invention discloses a network construction type converter constant frequency parallel synchronization method and system based on DC side Boost converter control, and relates to the field of new energy power generation, and the method comprises the steps: presetting a reference instruction voltage and a reference instruction frequency of the AC side of a network construction type converter, and a reference instruction current of the DC side of the network construction type converter; collecting the machine side current of the grid-forming converter, the input current of the Boost converter, the alternating current side capacitor voltage and the direct current side capacitor voltage; determining phase information of the network-forming converter; generating a first voltage modulation wave signal; and generating a driving pulse of the AC side IGBT of the grid-forming converter. According to the invention, a DC voltage synchronization control link is added in a control circuit of the constructed network type converter, and direct voltage synchronization control is adopted to realize output voltage amplitude, frequency following instruction, output power uniform distribution and output voltage phase synchronization of the constructed network type converter based on DC side Boost converter control.

This invention discloses a hierarchical control method and system for a three-phase on-board charger based on battery state. The method includes: acquiring battery state data of the on-board power battery, the battery state data including at least battery voltage and battery state of charge; determining a charging mode based on the battery voltage and / or battery state of charge; controlling the PFC converter to operate in a constant voltage output mode when the charging mode is a first charging mode, while simultaneously performing voltage following control on the bidirectional DC-DC converter based on the battery voltage; and performing voltage following control on the PFC converter based on the battery voltage when the charging mode is a second charging mode, while simultaneously controlling the bidirectional DC-DC converter to operate in a constant frequency or constant phase output mode. This invention adaptively adjusts the output voltage of the PFC converter by setting hierarchical control strategies under different operating conditions, optimizes the voltage regulation ratio under different operating conditions, improves the overall circuit structure, and enhances the charging efficiency of the on-board charger across the entire operating range.

To provide an air conditioner capable of suppressing an increase in power consumption while maintaining a certain degree of comfort.SOLUTION: The air conditioner includes an indoor unit, an outdoor unit, a refrigerant pipe, a compressor, an expansion valve, and a control part. The control unit is capable of executing a normal operation mode in which normal operation control is executed in which conditioned air is blown out from the indoor unit by controlling an operating frequency of the compressor in accordance with a set temperature set in the indoor unit and a room temperature of a room in which the indoor unit is installed, and a weak operation mode in which constant speed operation control is executed in which conditioned air is blown out from the indoor unit by controlling the compressor at a constant speed operating frequency that is lower than a maximum operating frequency that is possible in the normal operation control regardless of the room temperature.SELECTED DRAWING: Figure 8

The utility model relates to a power supply control circuit, a switching power supply and a microwave oven, the circuit comprises a transformer, a voltage doubling circuit and a frequency switching module, the primary end of the transformer is connected with a signal input circuit; the voltage doubling circuit is connected with the secondary end of the transformer; the first end of the fixed-frequency module is connected with the voltage doubling circuit, and the second end of the fixed-frequency module is connected with the output interface; the first end of the frequency conversion module is connected with the voltage doubling circuit; the second end of the frequency conversion module is connected with the output interface; the output interface is used for connecting a fixed-frequency magnetron or a variable-frequency magnetron; and the frequency switching module is configured to conduct the fixed-frequency module when the output interface is connected with the fixed-frequency magnetron and conduct the frequency conversion module when the output interface is connected with the frequency conversion magnetron, so that power supply control suitable for different magnetrons (fixed-frequency magnetrons or frequency conversion magnetrons) is realized, components in the circuit are reduced, and the cost is reduced. The circuit structure is simplified, the circuit cost is further reduced, and the universality of the switching power supply is improved.

This invention discloses a DCM mode constant frequency control method and system for a BUCK-BOOST converter, relating to the field of BUCK-BOOST converter operating mode control technology. The method includes: acquiring mode switching signals for the BUCK-BOOST converter entering DCM mode and BUCK mode; generating a mode switching command in response to the mode switching signal; and switching the control mode of the BUCK-BOOST converter's switching transistors from a valley current sampling control mode to a constant frequency peak current control mode in response to the mode switching command. The DCM mode constant frequency control method and system for a BUCK-BOOST converter proposed in this invention transforms the system into a peak current mode control mode. In this mode, the system frequency is determined by an internally generated fixed clock, thus achieving a constant frequency effect. Furthermore, the peak value of the inductor current in each cycle decreases as the load decreases, ensuring energy utilization and thereby reducing output voltage ripple.

The application discloses a generator with constant-speed frequency modulation function, which comprises a stator and a rotor, the stator comprises a stator core, a first winding and a second winding, the first winding and the second winding are both wound on the stator core, the second winding is closer to the rotor in the radial direction of the stator than the first winding, the rotor comprises a rotating shaft, a first rotor magnetic pole group and a second rotor magnetic pole group arranged in the circumferential direction of the rotating shaft, the second rotor magnetic pole group is closer to the stator in the radial direction of the rotor than the first rotor magnetic pole group, the polarity of the magnets constituting the first rotor magnetic pole group and the second rotor magnetic pole group changes alternately in the respective circumferential directions, the pole number of the first rotor magnetic pole group and the second rotor magnetic pole group is different, the pole number of the first rotor magnetic pole group is the same as that of the first winding, and the pole number of the second rotor magnetic pole group is the same as that of the second winding. The application can realize variable frequency output under constant rotating speed without adopting power power electronic devices frequency conversion.

The application discloses a transient matching squeeze transform method for reservoir boundary delineation. The method comprises the following steps: inputting seismic data to be analyzed; calculating group delay (GD) and a group delay band center in a short-time Fourier transform time-frequency domain of given data; calculating a group delay band boundary; matching all GD estimators in the group delay band with a GD estimator at the GD band center to obtain a matching GD estimator; squeezing time-frequency coefficients to obtain a transient matching squeeze transform (TMST); performing time-frequency transform on the seismic data according to the TMST to obtain time-frequency results; extracting a time sequence corresponding to a constant frequency from different seismic trace time-frequency spectrums obtained from the TMST, and obtaining a profile by synthesizing the time sequence, so that reservoir characteristics are represented and a reflection interface position is located. The method combines the advantages of a time redistribution synchronous squeeze transform (TSST) and a transient extraction transform (TET), and has strong sharpening performance and reconstruction performance.

A radar level gauge system and method for determining the fill level of a product in a storage tank are disclosed. The radar level gauge system includes: a transmission line probe; a transceiver coupled to the transmission line probe, the transceiver including: a first signal generator connected to the transmission line probe and controllable to generate a transmit signal including a measurement scan across frequencies defined by a first frequency and a second frequency; a second signal generator configured to generate an offset signal having a constant frequency lower than the first frequency; a first mixer for mixing the transmit signal and the offset signal to form a first mixer output signal; and a second mixer for mixing the first mixer output signal and a reflected signal to form a second mixer output signal; and processing circuitry coupled to the transceiver and configured to determine the fill level based on the second mixer output signal.

The invention relates to the technical field of bolt detection, and discloses an iron tower bolt tightness detector and a detection method thereof.The iron tower bolt tightness detector comprises a detection host, a vibration sensing probe and an automatic bolt fastening robot arm, and the vibration sensing probe is arranged around a bolt; the detection host is respectively connected with the vibration sensing probe and the automatic bolt fastening machine arm; the vibration sensing probe is used for collecting iron tower vibration response data, and the target iron tower structure is knocked at a constant frequency according to a preset period to generate the iron tower vibration response data; and the detection host is used for carrying out bolt tightness detection on the iron tower vibration response data, and if the bolt tightness is larger than a preset threshold value, the automatic bolt fastening machine arm is controlled to carry out fastening operation on the abnormal bolt. The problem that the bolt tightness cannot be effectively judged through personnel inspection is solved, the method is more scientific and efficient than personnel inspection, the accuracy is high, and stable operation of the power transmission tower is ensured.

The application provides a network construction control method and device, which are applied to network construction type equipment (including new energy power generation devices and power electronic devices) adopting a network construction type control strategy. The power electronic devices are used for incorporating the new energy power generation devices into a power grid. The method comprises the following steps: determining an actual power value output by the power electronic devices to the power grid; determining a power deviation value according to a difference between the actual power value and a power reference value; processing the power deviation value according to a preset strategy to obtain a target signal; determining a phase angle of a voltage output by the power electronic devices to the power grid according to the target signal; and adjusting the voltage output by the power electronic devices to the power grid according to the phase angle. The application adds a power dead zone link (i.e. implements the preset strategy) in the network construction type control. When the power is located in the dead zone, the phase angle output by the network construction type equipment is unchanged, and the network construction type equipment presents a voltage source characteristic with constant frequency and phase angle, so that the frequency support capability and stability of the network construction type equipment can be effectively improved.

This invention discloses a method, apparatus, electronic device, and storage medium for frequency construction in an asynchronous islanded operation mode of a flexible interconnected distribution network, belonging to the field of power system operation and control. The method includes: acquiring configuration information of multiple converters and the communication network status of the islanded ports of the interconnected converters; determining whether a grid-type converter exists based on the configuration information; when no grid-type converter exists, controlling the islanded ports to use constant frequency control to establish the islanded grid frequency; when a grid-type converter exists, selecting the control mode according to the communication status: when communication is normal, the islanded ports use constant frequency control, and the grid-type converter uses master-slave coordinated control; when communication is abnormal, the islanded ports use virtual synchronous generator control, and the grid-type converter uses frequency droop control to construct the islanded grid frequency. By implementing this invention, the problems of poor stability and insufficient adaptability in islanded frequency construction of existing flexible interconnected distribution networks can be solved.

The application relates to a detection and communication integrated identification method for instantaneous permanent fault of a power collection line by means of IIDG active energy injection, and belongs to the technical field of power system relay protection and automation. The method comprises the following steps: after a fault occurs in a power collection line, starting an IIDG with network construction capability, realizing zero starting voltage rise through VF control, establishing a characteristic voltage, judging whether a composite voltage criterion is met, if yes, the fault is permanent, and the injection source exits after maintaining a constant frequency transmission; if not, the fault is instantaneous, and the injection source sends a frequency shift information after a time delay. Voltage is continuously monitored during the injection, and whether a complete frequency shift signal is received is determined through a frequency variance criterion and data segment correlation. If the voltage does not meet the composite voltage criterion during the detection process and the complete frequency shift signal is received, reclosing is allowed after power loss again, otherwise, reclosing is locked. The method aims to solve the technical problem that the fault nature of the power collection line under a voltage loss condition is difficult to identify in the prior art.

The invention relates to the technical field of vibration reduction and isolation engineering elements, in particular to a dynamic vibration absorption unit pile for fixed-frequency vibration isolation. Due to the fact that a vibration source generated by industrial mechanical equipment is generally low-frequency strong-pulse fixed-frequency vibration, the dynamic vibration absorption unit pile for fixed-frequency vibration isolation is adopted on a path where vibration of a vibration source body is transmitted to a protected vibration sensitive target. Fixed-frequency vibration generated by a vibration source body is absorbed through an outer-layer pipe pile connected with an outer elastic body to generate resonance, an inner-layer vibration absorption pile is connected to the inner side of the outer-layer pipe pile through an inner elastic body, and based on the dynamic vibration absorption principle, resonance energy generated by the outer-layer pipe pile is absorbed through a dynamic vibration absorption system composed of the inner elastic body and the inner-layer vibration absorption pile; fixed-frequency vibration energy transmitted by a vibration source body can be effectively absorbed on a vibration transmission path, and therefore the purpose of effective vibration isolation is achieved.

By extending the lifespan of the refrigeration unit and reducing the frequency of replacement, the operating rate of the MRI system will be improved. [Solution] The processor has a mode for when shooting and a mode for when not shooting. In the shooting mode, the displayer is operated continuously at a constant frequency, regardless of the pressure inside the superconducting magnet container.

An object is to extend a replacement lifetime of a cryocooler and reduce a replacement frequency of the cryocooler, thereby improving an operating rate of an MRI apparatus.A cold head lifetime extension mode is executed. In the cold head lifetime extension mode, a displacer of a cryocooler is driven at a constant frequency that is lower than a predetermined upper limit frequency regardless of a temperature of a superconducting coil, and a drive frequency of a compressor drive unit adjusted by an inverter for a compressor is controlled in accordance with the temperature of the superconducting coil.