335 results about "Variable frequency control" patented technology

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.

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 embodiment of the invention provides an ultrasonic knife control method and device, medical equipment and a storage medium, an ultrasonic knife comprises a first piezoelectric vibration assembly and a second piezoelectric vibration assembly, the first piezoelectric vibration assembly is used for generating ultrasonic waves based on a resonance mode, the second piezoelectric vibration assembly is used for collecting the output frequency of the ultrasonic waves, and the output frequency of the ultrasonic waves is converted into the output frequency of the ultrasonic waves. The ultrasonic knife control method comprises the steps that when a frequency conversion control instruction is received, the jump frequency of the frequency conversion control instruction is determined; obtaining the output frequency; determining a target frequency in combination with the hopping frequency and the output frequency; and controlling the first piezoelectric vibration assembly based on the target frequency and the output frequency. The target frequency is determined through the hopping frequency based on the frequency conversion control instruction, frequency hopping control is conducted on the first piezoelectric vibration assembly, the characteristics of different vibration waves are output, and the using effect of the ultrasonic knife is improved.

The invention relates to the technical field of centrifugal machines, in particular to a variable-frequency energy-saving automatic control system of a centrifugal machine, which comprises a centrifugal module used for separating materials according to the centrifugal machine to obtain a target product and comprising a driving motor used for providing centrifugal power; the data processing module comprises a data acquisition unit used for acquiring operation data of the centrifugal machine; the frequency conversion self-control module comprises a main MCU (Microprogrammed Control Unit) for outputting an adjusting strategy of the centrifugal machine according to a neural network model; the counting adjusting module is used for determining the counting frequency of the timer in the slave MCU according to the start-stop response duration of the driving motor; the feed-forward adjusting module is used for determining the feed-forward lead of the auxiliary motor according to the phase deviation value of the PWM signal; and the cache adjustment module is used for determining an operation data cache trigger threshold according to the slave MCU instruction response deviation duration. The real-time performance of frequency conversion self-control of the centrifugal machine is improved.

The invention discloses a deep-well pump operation frequency conversion control method and system, and particularly relates to the technical field of liquid level automatic control. Based on the water level and the water level change rate, operation modes are intelligently judged and switched, and a dynamic water supply mode and a static maintenance mode are included; intelligent wakeup and protection are realized in a static maintenance mode; according to the sleep frequency self-learning algorithm, the sleep frequency and the wake-up water level are updated according to the real-time working condition; and multi-stage protection logic is integrated in the whole process. According to the invention, through the improved variable parameter PID control, the static maintenance and intelligent wake-up mechanism and the online self-learning ability, the system adjustment precision, the energy-saving effect and the adaptive ability are improved, and meanwhile, the reliability and safety of the system are enhanced through the multi-level protection logic.

The invention provides a high-power rectification resonance control method and system for a quick charger, relates to the technical field of rectification resonance, and aims to obtain direct-current bus voltage, adjust output power through frequency modulation of a full-bridge LLC resonant converter, and perform voltage stability control adjustment in combination with feedback current data. Charging curve data analysis is carried out to acquire charging key nodes and resonance frequency nodes, device state data acquisition and analysis are carried out, a frequency conversion control loop is constructed, resonance frequency adjustment is carried out, after adjustment is completed, abnormal nodes are identified and combined analysis is carried out, optimal parameters of each load segment are acquired, and voltage fluctuation data are acquired. The method comprises the steps of carrying out fluctuation influence analysis, carrying out fluctuation suppression by adjusting a switching frequency and phase shift angle combination of a full-bridge LLC resonant converter, carrying out calculation through the full-bridge LLC resonant converter to obtain an equivalent voltage control instruction, carrying out mode buffer switching and obtaining mode control switching data, and realizing rectification resonance accurate control of the charger.

The invention discloses a hydrogen production alkali liquor circulation system adapting to wind and light fluctuation and a control method of the hydrogen production alkali liquor circulation system, and solves the problems that in the prior art, an alkali liquor circulation path of an alkali liquor circulation system is fixed, the adjusting capacity is limited, and a dynamic buffering and quick response mechanism is lacked. The separator is connected with an alkali liquor circulating pump, the alkali liquor circulating pump is connected with an inlet of the electrolytic cell, the alkali liquor circulating pump is connected with an alkali liquor circulating buffer tank, an automatic regulating valve is arranged between the alkali liquor circulating pump and the alkali liquor circulating buffer tank, and a flowmeter A is arranged between the separator and the alkali liquor circulating pump. A flow meter B is arranged between the alkali liquor circulating pump and the electrolytic bath, the alkali liquor circulating pump is connected with a frequency conversion control system, and the frequency conversion control system adjusts the operation frequency of the alkali liquor circulating pump according to a current signal of the electrolytic bath. The alkali liquor circulation flow is adjusted through current signal adjustment and a frequency conversion control strategy, and the response speed and stability of the system are improved.

The invention relates to the technical field of gas compressor control, in particular to a gas compressor working condition self-adaption frequency conversion control method which comprises the steps that 1, multi-dimensional operation parameters are collected and preprocessed in real time; 2, real-time surge margin calculation and safety boundary dynamic construction are carried out, the real-time pressure ratio and the equivalent correction flow are calculated according to the real-time operation parameters preprocessed in the step 1, a preset compressor characteristic map is inquired, and the real-time surge margin is calculated; step 3, adaptive efficiency optimization and rotating speed decision making based on model prediction; and step 4, smooth issuing and closed-loop monitoring of a frequency conversion instruction: the optimal frequency set value obtained in the step 3 is processed through a smoothing algorithm and then is issued to the frequency converter, and closed-loop monitoring and emergency protection logic processing are carried out in the frequency adjustment process. Through a smooth instruction and closed-loop monitoring, oscillation and unnecessary energy consumption possibly caused in the control process are reduced.

The invention provides an intelligent variable-frequency dust fall system for a construction site. A flying dust monitoring module is used for monitoring dust particulate matter information of the construction site; the dust falling module is used for carrying out dust falling operation on the construction site; the water supply module is used for collecting treated water so as to supply water to the dust falling module during the dust falling operation; the frequency conversion control module is used for controlling respective working states of the dust falling module and the water supply module according to the dust particulate matter information, and dynamically regulating and controlling operation of dust falling equipment by detecting the dust particulate matter information of flying dust in real time, so that accurate and efficient flying dust treatment is realized, the utilization efficiency of water resources and energy can be optimized, and the dust falling equipment can be flexibly suitable for various construction environments; the flying dust treatment effect and the resource saving capacity are remarkably improved, and the problem of air pollution caused by flying dust on the construction site is effectively solved.

The invention discloses an electrosurgical radio frequency inverter based on model predictive control and a frequency conversion control method thereof, and the method comprises the steps: building a discrete output voltage prediction model based on a topological structure of the electrosurgical radio frequency inverter, and judging a switching frequency switching point and voltage peak output power through single sampling period iterative calculation. Constructing an output power prediction model; obtaining instantaneous prediction output power and theoretical reference output power obtained by real-time sampling and calculation when the output voltage is changed to a periodic peak value, and constructing a model prediction control evaluation function; according to the evaluation function, real-time voltage sampling and multi-frequency iteration prediction are combined with a set control target, the switching frequency of the radio frequency inverter is predicted and updated in real time, and constant-power frequency conversion control over the radio frequency inverter is achieved by continuously obtaining the control quantity at the next moment. The system can adapt to constant power output of a power supply under biological impedance change, can predict and control constant power output of an electrosurgical inverter in real time based on real-time updating of switching frequency, has good dynamic response performance, guarantees high efficiency and safety of clinical operations, and can be applied to various electrosurgical working platforms.

The invention provides an intelligent warehousing system, a stacking machine and a control method of the stacking machine, and relates to the technical field of intelligent warehousing. The stacking machine is suitable for moving goods among the multiple goods grids; the stacker adopts frequency conversion control; the control method comprises the steps of obtaining an operation instruction and analyzing a target position; planning a motion path according to the current position and the target position of the stacker; wherein the path planning is based on a three-axis coupling dynamic model, the shortest total operation time is taken as a target function, and the dynamic parameter difference of each axis is comprehensively considered to optimize the speed curve matching relationship of each axis; generating a smooth speed curve for each motion axis according to the motion path, wherein the speed curve adopts a segmented continuous S-shaped acceleration and deceleration model; wherein if yes, it is judged that the stroke is a long stroke, and a standard seven-section S-shaped speed curve is adopted; if not, the stroke is short, and five or three sections of simplified S-shaped curves are adopted; and the stacking machine is moved to the target position according to the movement path and the speed curve.

The invention belongs to the technical field of underwater construction and protection engineering, and discloses a grouting construction and flushing visual simulation system and method for underwater protection engineering, and the system comprises a circulating water flow part which comprises a water pump, a circulating water tank and a visual simulation water tank which are sequentially connected end to end through a water pipe; the centralized control part comprises a data control unit, a variable frequency controller for controlling the rotation of the water pump, a regulating valve, a flow meter, a grouting assembly and an underwater camera device which are electrically connected; the deformable base module comprises a plurality of electric telescopic supports distributed on the periphery of the basic model body and a flexible rubber film covering all the electric telescopic supports in a sealed mode. The system adopts an electric control closed-loop adjusting structure, can control the pump speed and the valve opening degree, realizes that the flow velocity fluctuation precision is controlled within + / -1%, and can simulate various dynamic flow fields; the deformable scouring foundation module can generate different bottom bed conditions according to test requirements, and the working condition reproduction capacity and adaptability of the system are greatly improved.

A same-frequency blowing system and working method belong to the technical field of square tube cutting. The system blows the square tube head and tail simultaneously while cutting, and the blowing device is linked with the cutting power supply, effectively saving energy. The system ensures that the tail blowing mechanism does not collide with the running square tube. When the square tube advances, the floating roller rotates around the rotating bearing after being pushed by the square tube, and turns to the lower side of the square tube. When the square tube is taken away, the floating roller reverses and rotates around the rotating bearing under the gravity of the weight. According to the dust collection mode of steel plate plasma cutting operation, the dust collector adopts frequency conversion control, blowing is added on one side of the smoke suction port, the smoke dust collection effect is improved, the electric energy is saved, the blowing distance is closer, the control is more sensitive, the effect is better, the smoke dust diffusion problem can be effectively solved, the environmental pollution is reduced, and the normal use of the equipment is ensured.

The invention relates to an intelligent multi-protection frequency conversion control method and system for a compressor, and the method comprises the steps: receiving a resistance value of an external resistor, setting an under-voltage protection voltage point and an overvoltage protection voltage point of the system according to the resistance value, receiving a resistance value signal of an external speed regulation resistor, and setting the under-voltage protection voltage point and the overvoltage protection voltage point according to the resistance value; the method comprises the following steps: determining a target rotating speed according to a pre-stored resistance-rotating speed mapping relation, further generating a corresponding PWM control signal to drive a compressor, monitoring voltage, current, temperature and motor phase state parameters of a system in real time, triggering a fault signal when any fault of overvoltage, undervoltage, overcurrent, phase loss or over-temperature is identified, and outputting the fault signal. According to the specific fault type identified in the fault diagnosis step, an indicator light is controlled to output a fault code of a corresponding specific flicker sequence, the internal temperature of the frequency converter is monitored, a cooling fan is started when the temperature exceeds a fan starting threshold value, and the cooling fan is closed when the temperature is lower than a fan stopping threshold value.

The application is a control method of a wide voltage range CLLL resonant converter for an energy storage system, which comprises the control of the energy storage system in three different stages of constant current charging, constant voltage charging and constant current discharging s The bridge phase shift angle is used to realize wide voltage gain control, and the switching frequency f s is adjusted to be equal to the resonant frequency f r to realize constant voltage gain control, and the switching frequency f s is adjusted to realize wide voltage gain control. In the control of the three different stages, all the switching devices of the CLLL resonant converter can realize soft switching operation. Compared with the frequency control, the switching frequency of the converter in the control method does not exceed the resonant frequency, the switching frequency is lower, the variation range of the switching frequency is narrower, which is beneficial to the design of the transformer and the driving circuit, and the converter has a wider voltage adjustment range in the step-down mode.

The application discloses a kind of water pump AC frequency converter energy-saving optimization control system, it is related to water pump energy-saving control technical field;Including: database, identification perception module, operation optimization module and control feedback module.Database acquires water pump operating parameter, and based on this and calculates lift, water pump efficiency and load rate;Identification perception module is based on lift, water pump efficiency and load rate deviation analysis constructs fusion deviation curve, and based on this obtains judging index to analyze curve area, to identify inefficient operation scene;Operation optimization module determines target flow, target lift according to end water demand and pipe network pressure demand, and obtains target frequency in combination with water pump similarity law and efficiency, lift deviation correction;Control feedback module implements frequency conversion control according to target operating parameter, and real-time feedback and secondary correction are carried out to execution result, form closed-loop optimization control, improve energy efficiency identification ability under low load condition, reduce water pump operating energy consumption.

The utility model relates to the technical field of automobile intercoolers, and discloses a high-compression-resistance and high-strength automobile intercooler which comprises an intercooler body, and the back face of the intercooler body is fixedly connected with an air inlet pipeline and an exhaust pipeline. And the auxiliary heat dissipation mechanism is arranged on the front face of the intercooler main body, and the auxiliary heat dissipation mechanism is used for conducting auxiliary heat dissipation on the intercooler main body when the automobile runs at a low speed. Through the overall design of the auxiliary heat dissipation mechanism, the electric cylinder can stretch when an automobile runs at a low speed to drive the strip-shaped pipe to move to the middle of the front face of the intercooler body, then the frequency conversion control draught fan is controlled to work, air is absorbed from the bottom, and then the air is conveyed into an inner cavity of the strip-shaped pipe; and the air passes through the through holes and is uniformly jetted to the front surface of the intercooler main body, so that the flow rate of the air is actively increased, heat on the intercooler main body is taken away, the heat dissipation effect of an automobile during low-speed driving is improved, and the working stability of an automobile engine is guaranteed.

The invention provides a fan temperature-sensing frequency conversion control method and system for flexible production of an aluminum-silicon alloy electrolytic cell. The fan temperature-sensing frequency conversion control method comprises the steps that preset control parameters related to flexible production of the aluminum-silicon alloy electrolytic cell are obtained; temperature parameters during flexible production of the aluminum-silicon alloy electrolytic cell are collected; according to the collected temperature parameters, reference temperature parameters in the control parameters, reference frequency parameters in the control parameters and a preset control strategy, the target frequency of the draught fan is calculated; and on the basis of the target frequency, a frequency converter connected with a fan motor is controlled to operate, accurate and dynamic matching of the air volume of the fan and the production working condition is achieved, the energy consumption of the fan is reduced, and the control flexibility is improved.

The application discloses an input open-phase and unbalance detection method, a frequency converter and a frequency conversion control device. The detection method comprises the following steps: obtaining a ripple period of a bus voltage and an output current; if the ripple period is consistent with an open-phase period, the frequency converter is operated to the maximum frequency, and then whether the output current is stable is detected; according to the detection result, whether the three-phase power supply input is open-phase or unbalanced is judged, and then the frequency of the frequency converter is reduced or a voltage stabilizing module is executed to stabilize the output current. The application accurately judges whether the three-phase power supply is input open-phase or unbalanced through the ripple period and the output current, then the output current is stabilized by reducing the frequency of the frequency converter first, if the output current is still unstable, the voltage stabilizing module is executed to stabilize the output current, so that the load continues to operate preferentially, the shutdown condition is avoided, and the needs of users are met.

The invention relates to the technical field of oil and gas field development engineering and intelligent control, in particular to a polymer dry powder direct distribution fracturing fluid remote data transmission control system which comprises an environmental parameter acquisition center used for acquiring the conductivity, the fluid temperature, the fluid pH value, the mineralization degree and the dry powder polymer nominal molecular weight of a fracturing operation site. The data is sent to the dynamic reference construction unit; the dynamic reference construction unit is used for obtaining theoretical equilibrium viscosity and a characteristic swelling time constant, and constructing a theoretical reference evolution equation by utilizing the theoretical equilibrium viscosity and the characteristic swelling time constant; the space-time mapping sensing unit collects main path mixed flow to obtain an actually measured dissolution rate signal; the active factor identification unit is used for calculating a polymer dissolution active factor; the cascade feedback control unit generates predicted final value viscosity and a screw feeder frequency conversion control signal, and constructs a semantic feature transmission vector; accurate feedforward control over the performance of the fracturing fluid is achieved, and the hysteresis problem of traditional control is solved.

The invention relates to the technical field of equipment automatic control technology, and discloses an intelligent frequency conversion control system and adjusting method for a closed water tower, and the system comprises a sensor module, a control module, a frequency conversion module, a man-machine interaction module, an alarm module, and a self-adaptive learning module. The sensor module is used for collecting key parameters of the closed water tower; the control module receives the key parameters and generates a control instruction in combination with historical operation data stored by the adaptive learning module and a preset algorithm; the frequency conversion module adjusts the operation frequency according to the control instruction; the adaptive learning module is used for storing system historical operation parameters, adjustment instructions and corresponding operation effect data, and optimizing a preset algorithm of the control module through a deep learning algorithm; the preset algorithm is a composite adjustment algorithm based on the outlet water temperature deviation, the environment correction coefficient and the flow pressure cooperation factor, and the energy saving performance, the stability and the self-adaptive capacity of the system can be integrally improved.

This invention relates to F24 15 / 20, specifically to an intelligent kitchen fume extraction system. The intelligent kitchen fume extraction system includes a stove, a fume hood, a temperature sensor, a main control unit, a frequency converter, an electric fume extraction regulating valve, a fan unit, an electric air conditioning fresh air regulating valve, an air conditioning fan, and a power supply for the main control unit. The intelligent kitchen fume extraction system provided by this invention facilitates data monitoring by staff, improves kitchen ventilation while achieving high efficiency and energy saving. Furthermore, through the coordinated operation of multiple modules, this invention enhances kitchen comfort and effectively prevents malfunctions, ensuring stability and reliability.

This invention provides a variable frequency control method, system, computer, and readable storage medium for a heater. The method includes calculating a temperature difference; calculating a heating cycle and a stabilization power based on the temperature difference; determining the heating power of the heater based on the heating cycle; calculating a first airflow rate and a first oil injection rate of the fan based on the heating power; controlling the heater's heating according to the first airflow rate and the first oil injection rate; determining whether the temperature difference is within a preset range; if the temperature difference is not within the preset range, continuing to control the heater's heating according to the first airflow rate and the first oil injection rate; if the temperature difference is within the preset range, calculating a second airflow rate and a second oil injection rate of the fan; and controlling the heater's stabilization heating according to the second airflow rate and the second oil injection rate, thereby achieving variable frequency control of the heater. This invention can significantly reduce the energy consumption of the heater, while achieving heating and temperature stabilization of the heater in the fastest and most energy-efficient manner.

The utility model relates to an automatic control technology, in particular to a modularized hidden type fan frequency conversion controller structure, which comprises a case main body and an upper cover arranged at the top of the case main body, a variable-frequency driving module is integrally mounted in the case main body, and a man-machine interaction module is mounted outside the variable-frequency driving module; the top of the variable frequency driving module is provided with a fan, and the fan is in communication with the variable frequency driving module and the man-machine interaction module. Technical concepts of variable frequency driving, automation, embedded development, industrial design and the like are integrated. The device can realize slow start and stepless speed regulation of the fan, detect the real-time running state of the fan, and perform comprehensive protection on phase loss, overvoltage, overcurrent, undervoltage, over-temperature, overload and the like of the motor. The device is suitable for fan pumping and discharging, air supplementing systems and other scenes using fans in commercial kitchens, and can be in user-defined linkage with a purifier and a fire fighting system. Operation interfaces and functions can be quickly customized according to user requirements, and personalized customization requirements of customers are met.

A gas saving type gas shielded welding mechanism is characterized in that a rectification power supply circuit outputs direct current to a full-bridge frequency conversion circuit, a main controller drives the full-bridge frequency conversion circuit through a frequency conversion control module, the full-bridge frequency conversion circuit outputs frequency conversion alternating current to an alternating current output circuit, and the alternating current output circuit outputs alternating current. The alternating current output circuit is further connected with an alternating counting control circuit, the output end of the alternating counting control circuit is connected with a gas circuit control valve, and the gas circuit control valve is arranged on a gas supply pipeline of a welding machine protection gas gun. The device has the beneficial effects that the supply amount of protective gas can be reasonably controlled according to actual working conditions by combining the frequency control technology of the welding machine and carrying out low-cost transformation, and excessive gas waste is avoided.

The utility model discloses a frequency conversion heat dissipation control electric box which comprises an electric box shell, a heat dissipation air duct, a frequency conversion assembly, a control circuit assembly and a heat dissipation fan. The electric box shell comprises a back plate, a cavity formed in the first side of the back plate, a fresh air inlet and a fresh air outlet, wherein the fresh air inlet and the fresh air outlet communicate with the cavity. A through mounting hole is formed in the back plate; the control circuit assembly is installed in the cavity. The frequency conversion assembly is mounted on the mounting hole and comprises a frequency conversion controller arranged in the cavity and a radiator which is arranged in the heat dissipation air duct and is in heat conduction connection with the frequency conversion controller; the heat dissipation air duct is arranged on the second side of the back plate and comprises an air inlet and an air outlet which are communicated with the fresh air outlet; the air inlet and the air outlet are formed in the two sides of the radiator respectively. The heat dissipation fan drives external airflow to enter the cavity from the fresh air inlet, flow through the control circuit assembly and / or the variable frequency controller, flow through the fresh air outlet and the air inlet, enter the heat dissipation air channel, flow through the radiator and then are exhausted through the air outlet, and the heat exchange efficiency is further improved.

The application discloses a motor system efficiency improving system, device and vehicle permanent magnet synchronous motor. The motor system efficiency improving system comprises a CAN communication transceiving module, a torque coordination module, a variable frequency control module and a motor control module. The application receives instruction information sent by a vehicle controller through the CAN communication transceiving module, analyzes the instruction information, processes the analyzed instruction information through the torque coordination module, obtains target instruction information, processes the target instruction information through the variable frequency control module, obtains frequency information and current loop control parameter information, switches the motor control mode according to the target instruction information through the motor control module, and improves the motor efficiency according to the frequency information and the current loop control parameter information. The application realizes closed-loop control of the motor according to the current loop control parameter information through the motor control module, and improves the motor efficiency according to the frequency information.

The present application relates to the technical field of frequency converter energy saving, and particularly relates to a mine-used explosion-proof frequency converter energy saving optimization system, which specifically comprises: an upper computer, a switch, a PID controller, a power distribution cabinet, a frequency converter, a driving motor, a belt conveyor, a laser radar sensor, a speed sensor and an intelligent frequency conversion module; the present application aims at the problem that the traditional coal flow measurement method of the transport scale causes a delay between measurement and control, uses the laser radar sensor to measure the coal flow on the belt conveyor in an integral method, eliminates the hysteresis effect and improves the measurement accuracy; aiming at the problem that the traditional PID control strategy has low control accuracy, the intelligent frequency conversion module is proposed, and the energy saving optimization model based on the BP neural network and the PID control model based on the fuzzy neural network are used in the intelligent frequency conversion module to realize the frequency conversion control of the belt conveyor, so that the belt conveyor can maintain high energy saving efficiency and high reliability.

The application provides a shutdown control method of a variable frequency controller and a variable frequency air conditioner. The variable frequency controller is used for controlling the operation of a compressor. The method comprises the following steps: collecting the phase current of the compressor, and estimating the rotor phase position of the compressor according to the phase current; determining the shutdown timing of the compressor according to the rotor phase position of the compressor, wherein the rotor phase position of the compressor is located outside a first preset phase interval at the shutdown timing, and the first preset phase interval is the first phase interval with the maximum vibration and stress after the current moment; and shutting down the inverter driving signal used for driving the compressor at the shutdown timing. The PFC circuit driving signal is shut down or the output DC voltage value of the PFC circuit is reduced at a preset moment before the compressor is shut down. This method avoids the occurrence of large amplitude vibration and noise at the shutdown moment of the compressor, and avoids the overshoot of the DC voltage at the shutdown moment, thereby improving the reliability of the variable frequency air conditioner.

This invention relates to a method for operating a modular brake regulator (1), wherein the modular brake regulator (1) includes at least one submodule (2) and a braking resistor (3), the submodule (2) and the braking resistor (3) being arranged in a series circuit (4). To improve the modular brake regulator, it is proposed to generate a voltage (u) using the at least one submodule (2). BR ), of which the generated voltage (u BR It has a DC component (u) BR,DC ) and alternating components (u BR,aDC ), where the alternating component (u BR,aDC The modular brake regulator (1) is designed such that the electrical energy absorbed by the brake regulator (1) over time is converted into heat energy in the brake resistor (3), wherein the alternating component (u) BR,aDC The modulation frequency (f) M The variation is based on the partial load factor (α) of the modular brake regulator (1). Furthermore, the invention relates to a control device (10) configured to perform the above-described method. The invention also relates to the aforementioned modular brake regulator (1) equipped with the control device, and a modular drive unit (20) having a modular multilevel converter (21) and a modular brake regulator (1).