1258 results about "Switching frequency" patented technology

The invention discloses a storage battery capacity attenuation trend prediction method, and belongs to the technical field of storage battery prediction. By collecting voltage, current and temperature data of each monomer in real time and combining historical capacity attenuation and internal resistance growth data, the method identifies a voltage and capacity difference value, evaluates cyclic stress non-uniform distribution, and determines a current sharing proportion and a load unbalance degree. Identifying an abnormal mode of new battery overload and aged battery deep discharge, constructing a mixing abnormal working condition identification mode, if the unbalance degree exceeds the standard, adaptively adjusting the charging and discharging time and the current switching frequency, establishing a load balance control framework, predicting the capacity attenuation rate and the residual cycle index of each monomer, and determining the capacity matching degree and the life matching degree; finally, a comprehensive residual life estimation value and a credibility interval are generated through fusion; the performance balance of the mixed battery pack is remarkably improved, the overall service life is prolonged, and the method is suitable for real-time monitoring of a battery management system.

The present application relates to the technical field of safety management, in particular to a mine air compressor safe operation management method and system based on deep learning, comprising the following steps: collecting output pressure and input current, calculating slope change rate and direction switching frequency, clustering fluctuation amplitude and frequency by time period, generating working condition fluctuation label, identifying state mutation point and duration, calculating risk level label, analyzing load fluctuation coefficient, judging periodic fatigue early warning, combining synchronous rate to identify abnormal section, judging the need to switch state and generating instruction set. In the present application, by constructing the load risk level sequence on the basis of state duration and mutation point identification, the quantitative identification of multi-period load deviation is realized, the early warning period is marked by combining risk level and fatigue deviation ratio, and the abnormal load trend is judged according to the change direction of pressure and return gas flow, which strengthens the capture ability of abnormal operation section and improves the accuracy of operation safety risk identification and the adaptability of response strategy.

The invention relates to the technical field of chip design, and discloses a chip dynamic power consumption scheduling method and system based on an intelligent algorithm. The method comprises the following steps of: firstly, acquiring instruction stream data operated by a chip in real time, extracting a feature vector comprising an instruction dynamic change vector and context associated data, and determining a power consumption prediction mapping parameter according to the feature vector; and when the parameter exceeds a preset threshold value, an accurate power consumption prediction result is generated by adjusting the weight of the convolutional neural network. Subsequently, a synchronous timing demand is calculated based on the instruction switching frequency and the data dependency, and an initial power supply configuration is determined. By monitoring task load classification signals, the power consumption distribution proportion is adjusted when the signals are lower than a threshold value, the optimized power supply configuration is obtained, and the improvement index of the resource distribution efficiency is calculated according to the optimized power supply configuration. And finally, according to the index, dynamically adjusting a limiting condition of a scheduling period, and forming a self-adaptive optimization framework, thereby realizing accurate prediction and dynamic optimization scheduling of the chip power consumption.

The invention relates to the technical field of capacitor manufacturing and state monitoring, in particular to a capacitor aging curve optimization method based on deep learning, which comprises the following steps: step 1, multi-modal data acquisition and standardization processing; 2, modeling and training a physical constraint neural network; 3, executing a dynamic control and maintenance strategy: dynamically adjusting the switching frequency of the inverter based on a comparison result of the residual life prediction value output in the step 2 and a preset threshold value, and enabling the ripple frequency to deviate from a capacitor impedance sensitive frequency band; and according to the aging mode classification result output in the step 2, triggering a corresponding temperature sampling frequency adjustment or bus voltage reduction operation. Through fusion of multi-modal data, a physically constrained neural network model and a dynamic control strategy based on a prediction result, the aging process of the capacitor is successfully optimized, the use efficiency of the capacitor is improved, and the life cycle of the capacitor is effectively prolonged.

A reconfigurable flying capacitor multilevel input stage accepts a wide range of input voltages. The input stage divides and inverts a DC input voltage. Generally, output voltage regulation is achieved by adjusting the power switches' duty ratio in the input stage for non-resonant converters and by adjusting the switching frequency for resonant converters.

The invention belongs to the technical field of LLC resonant converters, and provides an efficiency optimization method of a wide-range LLC resonant converter. The method comprises the following steps: firstly, obtaining a full-bridge LLC resonant converter topology and a working area; secondly, establishing a full-time-domain equation of the full-bridge LLC resonant converter topology in an inductive low-gain output working area, and setting boundary conditions of the full-time-domain equation; then, on the basis of boundary conditions, switching tube turn-off current is calculated, and the switching tube turn-off current is combined with switching tube switching frequency to be represented as switching tube turn-off loss characteristic quantity related to the inductance coefficient, the quality factor and the normalized frequency; then, carrying out characteristic analysis on the turn-off current of the switching tube, and setting constraint conditions; and finally, on the basis of the set constraint conditions, the optimal values of the inductance coefficient, the quality factor and the normalized frequency are calculated by combining a differential evolution algorithm, so that the turn-off loss of the switching tube is minimum. According to the invention, the transmission efficiency in a low-gain mode and a high-gain mode can be improved, and the turn-off loss of the switching tube is reduced.

The invention relates to the technical field of electric energy storage systems, and discloses an electric energy storage system hierarchical cooperative control method based on source-load-storage dynamic matching, and the method comprises the steps: obtaining a common connection point voltage sampling sequence, and calculating a second-order change rate; collecting the first-order change rate of the output current of the energy storage converter and determining a polarization constraint coefficient; switching a control mode according to a second-order change rate magnitude and a polarization constraint coefficient symbol, and utilizing a dynamic damping factor to constrain a duty ratio to adjust a step length; the dynamic damping factor is adjusted and increased when the polarization constraint coefficient exceeds a threshold value under the excitation and transformation state, so that the change rate of the output current is within the charge diffusion safety domain of the storage medium, dynamic damping is guided to implement asymmetric constraint through cooperation of trend pre-judgment and polarization stress identification, the output current is made to adapt to the charge diffusion limit, the switching frequency of the converter is reduced, and the stability of the converter is improved. Active substance precipitation is inhibited; and the total throughput of the equipment in the full life cycle is improved.

A method and circuit for controlling a bidirectional resonant direct-current converter are provided. The method includes obtaining an input and / or output electrical parameter of the converter; determining respective delay time periods of bridge arms in the secondary circuit based on the input and / or output electrical parameter and a desired gain of the converter; determining a switching frequency to be greater than a resonant frequency of the resonant tank based on the input and / or output electrical parameter and a preset reference signal; and turning off, in response to a secondary resonant current of the converter reaching zero, corresponding switching transistors of the switching transistors in the secondary circuit immediately after the respective delay time periods starting from a zero-crossing point; and turning on other switching transistors complementary to the turned-off switching transistors in the secondary circuit immediately after a dead time.

A dynamic grid allocation system for power distribution in the development of integrated circuits in the sub-five-nanometer range, wherein the system comprises the following: a placement processor unit configured to receive a synthesized netlist comprising a variety of standard cells and macros, each associated with switching activity data derived from simulation or synthesis activity profiles, and to generate a spatial cell placement arrangement by grouping cells into microzones based on activity correlation, time sensitivity, and connection proximity; a power density calculation unit coupled to the placement processor unit and configured to calculate the local power density and instantaneous current demand for each microzone based on the spatial distribution of switching operations, capacity load, and effective switching frequencies; a dynamic network generation unit coupled to the power density calculation unit and configured to generate a multilayer power distribution network with variable network topology, where the width, spacing, via density and metal layer assignment of the power network are adaptively determined as continuous functions of the localized power density and power demand calculated for each microzone; a topology control processor configured to monitor voltage drop and electromigration data obtained from signoff analyses or predictive models in real time and dynamically adjust the power grid topology parameters to ensure compliance with predefined reliability thresholds for voltage drop and electromigration; a predictive current modeling unit configured to receive historical switching and voltage data, train a predictive model for transient current peaks, and provide predictive power boost instructions to the dynamic grid generation unit before power integrity violations occur; and A feedback synchronization controller is communicatively connected to the placement processor unit and the topology control processor, whereby the feedback synchronization controller continuously exchanges updated power density information and placement constraints, so that cell placement and network topology adapt together in real time, thereby minimizing routing congestion, ensuring a uniform voltage distribution, and guaranteeing compliance with electromigration and IR drop regulations under various activity conditions.

The invention relates to the technical field of wireless communication, and discloses a three-frequency WiFi (Wireless Fidelity)-based wireless network adapter power consumption control method, which comprises the following steps of: acquiring a power consumption fluctuation amplitude and an interference suppression coefficient; performing eddy current effect strength evaluation on the power consumption fluctuation amplitude in combination with an interference suppression coefficient, so as to perform frequency band configuration parameter adjustment when the eddy current effect strength exceeds a preset threshold value, thereby obtaining frequency band configuration for reducing the interference suppression coefficient; power distribution proportion adjustment is carried out on frequency band configuration, the operating frequency range is adjusted according to real-time chip temperature data, then power level and frequency band switching frequency adjustment is carried out, and a power consumption control strategy is obtained; and finally, according to a power consumption control strategy, transmitting power level adjustment and frequency band priority adjustment are carried out to obtain an optimized transmission stability factor and an optimized interference suppression coefficient. By dynamically optimizing frequency band configuration and power consumption regulation and control, the transmission stability and energy efficiency of the wireless network adapter can be improved, and the power consumption and temperature anomaly risk are remarkably reduced.

The invention discloses an equipment operation safety detection method and system of an energy storage system, and relates to the technical field of energy storage system safety detection.The method comprises the steps that multichannel original data are collected and preprocessed, and multichannel signals are obtained; extracting an instantaneous frequency through adaptive decomposition and Hilbert transformation based on the multi-channel signal, performing modal reconstruction based on the instantaneous frequency, extracting a switch frequency band energy feature, an EMI feature, a DC ripple and a coherent feature, and constructing a fingerprint vector; collecting health state historical data, calculating a mean vector and a covariance matrix, and constructing a health template; based on the health template and the real-time fingerprint vector, analyzing a safety state through dual statistical judgment, and outputting a safety statistical magnitude; and judging abnormity based on the current safety statistics, performing LASSO sparse reconstruction by using a predefined typical fault template, and outputting a fault type. Therefore, efficient and accurate fault diagnosis and automatic alarm are realized.

A resonant converter having a switch on-time control mechanism is provided. The resonant converter includes a primary-side switch circuit, a primary-side resonant circuit, a secondary-side switch circuit, a secondary-side resonant circuit, a transformer and a control circuit. In the resonant converter, the control circuit controls on-times and switching frequencies of the primary-side switch circuit and the secondary-side switch circuit to extend time within which power is transmitted from an input power source, the primary-side switch circuit, the primary-side resonant circuit and the transformer to the secondary-side resonant circuit, and stored in the secondary-side resonant circuit. As a result, the secondary-side resonant circuit is able to supply more power to a load.

The invention discloses a dynamic core binding and energy efficiency optimization method and device based on a scheduling domain. The method comprises the following steps: analyzing a CPU topological structure when a kernel is started, and identifying and registering a Cluster scheduling domain; constructing a multi-level scheduling domain hierarchy comprising a Cluster layer, an MC layer and an NUMA layer; regularly detecting the utilization rate of the current scheduling domain, and dynamically switching the levels of the scheduling domain according to a comparison result of the utilization rate and a preset threshold value; and when it is detected that the scheduling domain level switching frequency exceeds a preset frequency threshold, starting an oscillation suppression mechanism. Through the three-layer elastic scheduling domain architecture comprising the Cluster layer, the MC layer and the NUMA layer and the dynamic oscillation suppression mechanism, the task scheduling efficiency and the system energy efficiency are optimized, fine-grained load balancing can be achieved, memory access delay can be reduced, scheduling domain level oscillation caused by short-term fluctuation and floating can be avoided, and the system stability can be enhanced.

The application provides a transient frequency conversion control method of a converter and an electronic device. The method comprises the following steps: determining the working state of the converter, wherein the working state comprises a light load working state and a heavy load working state; if it is determined that the working state switches between the light load working state and the heavy load working state, starting a transient frequency conversion control strategy to adjust the switching frequency of the converter, wherein the transient frequency conversion control strategy is used to adjust the duration of the freewheeling stage in the switching cycle of the converter; after the working state of the converter switches, and the clamping capacitor voltage sampling value of the converter v c satisfies a preset condition, exiting the transient frequency conversion control strategy to restore the switching frequency of the converter to normal. The dynamic response speed of the converter is effectively improved, and the overshoot and drop of the output voltage when the converter is subjected to a step load are reduced.

The invention provides a permanent magnet synchronous motor control method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring a sampling rotor electrical angular velocity of the permanent magnet synchronous motor, and determining a first shaft current instruction based on the sampling rotor electrical angular velocity; determining a reference voltage vector according to the first axis current instruction and a preset second axis current instruction; synthesizing a reference voltage vector by using the first preset number of non-zero vectors and the second preset number of zero vectors; determining a candidate voltage vector set by adjusting the number of voltage vectors acting in the control period and the acting time of each voltage vector; constructing a cost function based on the current error, the current harmonic and the switching frequency, and determining an optimal voltage vector combination and action time from the candidate voltage vector set according to the cost function; and determining a driving signal of each switching tube of the inverter based on the optimal voltage vector combination and the action time, and controlling the permanent magnet synchronous motor based on the driving signals.

The invention provides a control method of a photovoltaic energy storage system, the photovoltaic energy storage system and a control circuit. The photovoltaic energy storage system comprises a power supply mechanism, a hybrid energy storage mechanism and a control module. The hybrid energy storage mechanism comprises a super capacitor module and an energy storage module; according to the control method, a hysteresis control threshold value is dynamically adjusted based on real-time state information of multiple dimensions; the method comprises the following steps: collecting power grid side data, photovoltaic side data and load side data in real time, and respectively calculating various different power gap parameters and state abrupt change parameters; when the state abrupt change parameter triggers a transient response strategy in the hybrid energy storage hierarchical control strategy, the super capacitor module is controlled to compensate preferentially; and triggering a steady state control strategy in the hybrid energy storage hierarchical control strategy to control an energy storage module and a super capacitor module to access the DC bus for compensation based on the dynamically adjusted hysteresis control threshold and the matching result of the various different power gap parameters, thereby reducing the state switching frequency of the photovoltaic energy storage system.

The invention discloses a high-robustness deadbeat predictive current control method which is suitable for current control of a dual three-phase permanent magnet motor driving system, and belongs to the technical field of permanent magnet motor control. The method mainly comprises the following steps: reconstructing a motor mathematical model by adopting a space vector decoupling matrix and Park transformation to obtain a motor voltage equation under a dqxy axis; designing a linear expansion state observer; a reference value of an output voltage vector is obtained in combination with deadbeat predictive current control; time delay in the digital control system is calculated, and angle delay is compensated; and designing a closed-loop Smith predictor for compensating a time delay link to complete high-robustness dead-beat predictive current control of the dual three-phase permanent magnet motor. The current loop design in the method does not depend on motor parameters, and the method has high parameter change robustness. By introducing the closed-loop Smith predictor, large delay of the system can be effectively compensated, and high-precision current tracking is realized under low switching frequency.

The invention provides a grid-side current harmonic suppression method and device for a motor driving system without an electrolytic capacitor. The method comprises the following steps: determining first and second bus voltage harmonics based on bus voltage obtained by sampling and inverter switching frequency; correcting the bus voltage according to the first bus voltage harmonic wave and the second bus voltage harmonic wave so as to determine a reconstructed bus voltage; according to the second bus voltage harmonic, the reconstructed bus voltage, an inverter output three-phase duty ratio and a motor three-phase current, first and second network side current harmonic regulation and control voltages are determined based on a self-defined closed-loop controller; and adopting a motor alpha-axis correction voltage and a motor beta-axis correction voltage determined according to the first and second grid-side current harmonic regulation and control voltages to participate in motor SVPWM modulation to output the three-phase duty ratio of an inverter so as to suppress grid-side input current harmonics. According to the method and the device, factors such as motor operation conditions, bus voltage harmonic waves and digital control delay are comprehensively considered, the quality of grid-side input electric energy is improved, and disturbance to machine-side rotating speed and torque is reduced.

The invention relates to the technical field of new energy, in particular to an efficiency optimization method of a DAB converter, electronic equipment and a storage medium. The method comprises the following steps: calculating a staggered ratio coefficient and a first phase shift parameter in a heavy load mode and a first phase shift parameter in a light load mode according to an output power reference value, a battery side voltage sampling value and a bus side voltage sampling value; determining a second phase shift parameter and a switching frequency in the heavy load mode according to the staggered proportion coefficient and the first phase shift parameter in the heavy load mode, and determining a second phase shift parameter in the light load mode according to the first phase shift parameter in the light load mode; and determining a current working mode based on the staggered proportion coefficient in the heavy load mode and a preset dead zone proportion, and generating a driving signal of each power switch based on the first phase shift parameter, the second phase shift parameter and the switching frequency corresponding to the current working mode. According to the method, the overall efficiency of the DAB converter under different load conditions is improved.

The application discloses a resonant converter and a method for controlling the same. The resonant converter includes: a resonant tank, a first circuit electrically connected to a first end of the resonant tank, and a second circuit electrically connected to a second end of the resonant tank; the first circuit including at least one primary switch, the second circuit including at least one controllable switch, and controlling the at least one controllable switch according to a secondary initial switching frequency, such that the second circuit outputs power, adjusting a secondary switching frequency of the at least one controllable switch according to the secondary initial switching frequency and a signal reflecting the power of the second circuit, such that the secondary switching frequency of the second circuit follows a primary switching frequency of the first circuit.

The invention provides a motor vibration noise control method and system based on modal resonance frequency prediction, and belongs to the field of motor control. The method comprises the following steps: acquiring each order of intrinsic mode frequency of the permanent magnet motor; a cost function parameter, a current constraint condition and a control target are set, and a model prediction control method is adopted to drive an inverter to operate, specifically, the current operation state quantity of the permanent magnet motor is collected; predicting a state response in a future finite time domain based on the operation state quantity; constructing a value function, and evaluating and optimizing a state change result; and selecting an optimal voltage vector, generating a pulse signal to drive an inverter to execute, obtaining a motor high-frequency electromagnetic force wave distribution condition, comparing the motor high-frequency electromagnetic force wave distribution condition with the intrinsic mode frequency of the permanent magnet motor, and optimizing an optimal voltage vector selection logic. The problems that harmonic waves are concentrated and resonance is easily caused by a fixed switching frequency modulation method in the prior art, and a passive suppression method is high in cost and poor in flexibility are solved.

The invention discloses a switching control method based on SPWM soft start and a pulse type load LLC resonant converter. The converter mainly comprises an LLC resonant converter, an H-bridge inverter circuit and a load of the H-bridge inverter circuit, and the control method comprises the following steps: setting k-level SPWM modulation in a starting stage to realize smooth soft start of output voltage (k is any positive integer); the load state is accurately judged through an H-bridge switching logic unit, and Burst intermittent control and linear frequency control are adopted for no-load and full-load in a steady state respectively; during load switching, a nonlinear SOTC optimal trajectory controller is adopted to perform two-pulse optimal control, so that the state is transited to a new mode along the shortest trajectory, and a dynamic response optimizer is introduced to compensate the switched frequency according to the state radius error so as to suppress secondary voltage fluctuation. The problems of slow dynamic response, large output voltage fluctuation and the like when traditional linear control faces a pulse type load LLC resonant converter are solved, and the stability and the anti-interference capability of the output voltage of the system are improved.

A method operates a power converter having at least one series circuit of switching modules, which each have semiconductor switches and an energy store. In which method a switching frequency of the switching modules is controlled by tolerance based modulation, and the forming of a switching integral value for the tolerance based modulation takes into account an absolute amount of an arm current flowing through the series circuit. A power converter has a control device that is configured to perform the method.

The invention discloses an improved multi-vector combined model predictive control method and device for a permanent magnet synchronous motor. The method comprises the following steps: acquiring a three-phase current of each sampling period, and converting the three-phase current into a d-axis current and a q-axis current; performing one-beat delay compensation on the current, predicting a reference voltage of a next beat, and judging a sector where the reference voltage is located; selecting a corresponding voltage vector output combination in the reconstructed voltage vector selection table by combining the sector and the previous period zero vector; solving a cost function only containing voltage vectors and action time by using the KKT theorem, and calculating the action time of each voltage vector; and generating a pulse signal according to the action time for driving the output of an inverter of the permanent magnet synchronous motor. According to the method, the advantages of fast dynamic response, easy processing of multiple constraints and the like of model prediction control are maintained, and meanwhile, lower calculation complexity, fixed switching frequency and higher reliability are realized, so that the comprehensive performance of a permanent magnet synchronous motor control system is improved.

The invention provides a method for improving transient stability of a submarine direct-current power supply system based on frequency compensation. The method comprises the following steps: acquiring a real-time electrical parameter detection item of a first system; based on the first system real-time electrical parameter detection item, judging whether the system load power is within a power range required by a transient stable operation condition; if not, the switching frequency compensation amount of the input-series output-parallel resonant converter sub-module is calculated; based on the switching frequency compensation amount, determining a switching signal of a sub-module switching tube of the input-series output-parallel resonant converter; acquiring a real-time electrical parameter detection item of a second system; based on a second system real-time electrical parameter detection item, judging whether the system load power is within a power range required by a transient stable operation condition; if yes, conventional frequency conversion control is adopted. The technical blank in the field is effectively filled, and the stability of the submarine direct-current power supply system in the transient process is remarkably improved.

A triple-active bridge (TAB) converter and methods to optimize the same is disclosed. The TAB converter includes a high-frequency three-winding transformer and three active full bridges, each coupled to the high-frequency transformer through a different passive network. The converter also includes a centralized controller providing gating pulses to semiconductor switches within the active full bridges, a power pulsating buffer (PPB) configured to reduce capacitor requirements on the DC port, and an unfolder stage to convert rectified AC voltage to a pure sine wave. The centralized controller may optimize performance by varying at least one of a switching frequency, a duty cycle of bridge voltages, and a phase shift between bridge voltages. The PPB may include a buck active power decoupler with a half-bridge, inductor, and capacitors, and also a primary full bridge and a power transfer impedance block.

This invention provides a random frequency conversion control method for NVH (Noise, Vibration, and Harshness) of a motor controller in a pure electric vehicle. The method includes: simulating the full throttle pedal condition of the entire vehicle on an electric drive test bench to eliminate tire noise and wind noise interference, thereby obtaining a spectrum diagram of the NVH of the electric drive system at the IGBT base frequency under the full throttle pedal condition; analyzing the spectrum diagram to identify the prominent NVH noise range under the full throttle pedal condition, and using this prominent NVH noise range as the entry condition for random frequency conversion; establishing corresponding random frequency conversion models for different prominent NVH noise ranges based on the base frequency of the IGBT switching frequency, to perform random frequency conversion control on the prominent NVH noise ranges, and using the base frequency of the IGBT switching frequency for control in the non-prominent noise ranges. This invention can reduce the switching frequency noise of the motor controller and improve the NVH performance and safety of electric vehicles.

The invention relates to the technical field of heat pump units, and discloses a self-adaptive defrosting and oil return cooperative control method and device of a heat pump unit and a computer storage medium. The method comprises the steps that the current outdoor heat exchanger coil temperature parameter of the heat pump unit in the defrosting operation state is obtained, and according to the current outdoor heat exchanger coil temperature parameter, the heat pump unit in the defrosting operation state is defrosted; judging whether the heat pump unit meets a defrosting exit condition or not; if yes, target operation parameters of a compressor of the heat pump unit are obtained, and whether the heat pump unit meets the oil return time condition or not is judged according to the target operation parameters; if yes, the heat pump unit is controlled to execute the defrosting quit operation, and after the defrosting quit operation is completed, the heat pump unit is controlled to return oil, in this way, the self-adaptive defrosting and oil return cooperative control process of the heat pump unit is achieved, the unnecessary working condition switching frequency of the heat pump unit is reduced, and the unit can operate continuously; and the indoor temperature fluctuation is reduced, and the oil gas recovery efficiency is improved, so that the operation energy efficiency and reliability of the heat pump unit are improved.

The invention discloses a system reference clock frequency accuracy automatic calibration circuit and a calibration method thereof, and belongs to the technical field of frequency sources, the calibration circuit comprises a first crystal oscillator, a first power divider, a second power divider, a second crystal oscillator, an analog switch, a radio frequency switch, a detector, a comparator, an FPGA controller, a digital analog converter, an operational amplifier and a temperature sensor. When an external high-precision reference clock is accessed, the FPGA controller automatically switches a frequency measurement reference, performs high-precision frequency measurement on a 100MHz signal output by the first crystal oscillator, and judges whether calibration is needed or not according to frequency offset; if calibration is needed, the output voltage of the digital-to-analog converter is adjusted, the Vc end of the first crystal oscillator is controlled after operational amplification, and frequency closed-loop adjustment is achieved. According to the method, the crystal oscillator does not need to be disassembled, calibration is rapidly completed on site, and system availability and long-term frequency stability are remarkably improved.

The utility model discloses a constant-current and constant-voltage circuit without software control, which comprises a Buck power level circuit, a voltage sampling circuit, a current sampling circuit and an error amplifying circuit, and the error amplifying circuit is provided with a first error amplifier and a second error amplifier. The output end of the first error amplifier and the output end of the second error amplifier are electrically connected with the Buck power level circuit, the Buck power level circuit is electrically connected with the voltage sampling circuit and the current sampling circuit, the voltage sampling circuit is electrically connected with the first error amplifier, and the current sampling circuit is electrically connected with the second error amplifier. An FREQ pin of a Buck chip U4 is grounded, a 0.76 V voltage is obtained through voltage division by a resistor R27 and a resistor R29, so that the switching frequency of a Buck power level circuit is invalid, the voltage is controlled through a first error amplifier, the current is controlled through a second error amplifier, the first error amplifier and the second error amplifier carry out operation, and then a PWM comparator in the Buck chip U4 is controlled through a COMP pin of the Buck chip U4. Therefore, voltage and current are controlled.