397 results about "Variable-frequency drive" patented technology

The invention discloses a variable frequency driving device energy recovery control system based on direct power supply of a high-voltage power grid, and relates to the technical field of electrical transmission and energy recovery control. Updating the power grid impedance model in real time by using a complex impedance calculation method; load operation state parameters are dynamically adjusted in combination with motor end output power, rotating speed change and torque calculation; according to the method, regenerative energy is accurately calculated, a feedback path is adjusted according to voltage fluctuation and frequency deviation of a power grid, a feedback current fluctuation ratio and a power factor are monitored, a feedback path conduction proportion is optimized in real time, when the current is unstable or the power factor is abnormal, a suboptimal path is automatically switched, and continuous and stable operation of a system is guaranteed; according to the invention, the energy feedback efficiency and the power grid compatibility of the high-voltage power grid variable-frequency driving device are effectively improved, and the method is suitable for energy feedback application of a high-power motor driving system.

The invention relates to the technical field of motor fault diagnosis, in particular to a fault diagnosis method of a drilling machine variable frequency driving motor based on IMSOA-MCNN-BIGRU, and the method comprises the steps: collecting the current data of an experiment platform motor, and adding interference to simulate the data of a real drilling machine driving motor; a population initialization strategy of an SOA algorithm is improved, opposite-reverse learning is introduced in an iteration process, and an adaptive worst resampling mechanism after stagnation monitoring is added; the size of a convolution kernel, the size of a hidden layer, an initial learning rate and L2 regularization intensity of the MCNN-BIGRU model are optimized based on IMSOA, and optimized parameters are endowed to the MCNN-BIGRU model again so as to construct an IMSOA-MCNN-BIGRU classification model; and inputting the current data into which the interference is added into the IMSOA-MCNN-BIGRU classification model to obtain a diagnosis result. According to the method, the MCNN and the BIGRU are combined and complemented, the characterization capability and the fault judgment precision of complex non-stationary signals are improved, the MCNN-BIGRU model is optimized by using the improved sea gull optimization algorithm, and the performance of the model is improved.

The invention relates to the technical field of automatic packaging equipment, and discloses a cooperative control system for a filling electric cylinder and an adjustable stirring cylinder. The system comprises a filling electric cylinder module, a weighing measurement module, an adjustable stirring cylinder module and a cooperative controller module. The filling electric cylinder module executes the filling action and feeds back the position speed; the weighing measurement module collects the material weight of the container in real time and converts the material weight into liquid level height; the adjustable stirring cylinder module stirs materials through variable frequency driving and replaceable paddles; and the cooperative controller module receives real-time data of each module and SPC historical data, analyzes and generates a cooperative control instruction, and dynamically optimizes filling and stirring parameters. By means of modular integration and data closed-loop control, high-precision and self-adaptive filling is achieved, the problems that traditional equipment is difficult to adjust, insufficient in precision, poor in material adaptability and lack of intelligent feedback are solved, and the high-precision self-adaptive filling device is suitable for occasions with high requirements for filling precision and flexibility in the industries of food, medicine and the like.

A variable-frequency drive includes a rectifier, a filter, an inverter, a capacitor bank, and control circuitry. The rectifier converts AC power from a power source to DC power on a DC bus for filtering by the filter. The inverter converts the DC power to three-phase AC power for output to the electric motor. The capacitor bank has one or more capacitors connected to the DC bus. The capacitor bank can store regenerative power on the DC bus from the inverter and can supply the stored DC power to the DC bus for conversion to the three-phase AC power to drive the electric motor. The control circuitry pre-charges the capacitor bank from the AC power of the power source. The control circuitry monitors one or more parameters of the variable-frequency drive and detects one or more fault conditions associated with the one or more monitored parameters.

The invention discloses a variable frequency heat pump unit and a heat dissipation control method.The variable frequency heat pump unit comprises a refrigerant circulation loop and a variable frequency driving module, the refrigerant circulation loop is formed by connecting a compressor, a heat exchanger combination, a liquid storage device and a gas-liquid separator, and the variable frequency driving module is provided with a heat dissipation pipeline; the outlet end of the heat dissipation pipeline is connected to the air suction side of the compressor, the inlet end of the heat dissipation pipeline communicates with a liquid storage cavity of the liquid storage device through a first branch and a second branch, the first branch is provided with a cooling pipe section located in the gas-liquid separator, a first throttling device is installed on the outlet side of the cooling pipe section, and the second branch is located outside the gas-liquid separator. The second branch is provided with a second throttling device; the first throttling device and the second throttling device are adjustable in opening degree and work cooperatively. The liquid refrigerant in the liquid storage device is led out to dissipate heat of the variable frequency driving module, the influence of heat dissipation on main path circulation is reduced, and the heat dissipation efficiency and the unit performance can be both considered.

A monitoring device is for monitoring winding insulation condition of an electric motor, motor phases of which are connected to a variable frequency drive. The monitoring device is configured to determine whether the variable frequency drive is in a standby mode based on a signal received or obtained from the variable frequency drive, and to measure a standby voltage between at least one of the motor phases and the frame of the motor while the variable frequency drive is determined to be in the standby mode. The standby voltage is indicative of the winding insulation condition. A system includes a monitoring device and a variable frequency drive, and a method is for monitoring the winding insulation condition of a motor.

The invention discloses a power control method of an electric power system for polyester staple fiber production, and relates to the technical field of industrial power load cooperative control, and the method comprises the steps: collecting real-time process parameters and power grid state parameters of each energy consumption section, and calculating the expected basic power demand of each section through a section power consumption prediction model; and in combination with a power fluctuation range predicted by the power grid load fluctuation analysis model, a multi-target dynamic power distribution optimization equation is constructed for solving, so that a target set power value of each workshop section and a total regulation power instruction of the system are obtained. And the section level is adjusted to the variable frequency driver and the heating controller based on the instruction, and the energy storage unit or the standby unit is controlled to act. The method achieves the real-time precise prediction of the power demand of each workshop section, enables the total load of the system to actively cooperate with the fluctuation requirement of the power grid through dynamic optimization distribution, effectively guarantees the stability of the production technology, and improves the energy utilization efficiency and the response capability of the power grid.

The invention relates to a frequency converter dynamic performance optimization control method, and belongs to the technical field of power electronics. The method comprises the steps that frequency converter operation and device characteristic signals and external working condition correlation signals are collected in real time and integrated into a multi-dimensional operation data set, an analysis model is built, and a mapping relation is preset; extracting transient characteristics of a device switch, calculating a dynamic impedance parameter based on a mapping relation, and matching a parameter self-tuning rule base to generate a current loop proportionality coefficient, an integral time constant and a modulation wave duty ratio correction; a rotating speed and current double-loop fusion framework is built, the weight of an outer loop is dynamically adjusted according to rotating speed deviation and load sudden change, an inner loop adopts an adaptive reaching law and disturbance compensation, and a cooperative control instruction is generated through inter-loop interaction; monitoring instruction execution data to form feedback, correcting a model mapping relation and optimizing control parameters. The dynamic response precision of the frequency converter under complex working conditions is improved, the anti-disturbance capability is enhanced, and meanwhile, the device operation loss and the manual debugging cost are reduced.

A driving system includes: a power circuit (600, 700, 800) having a plurality of power cells supplying power to output phases (A, B, C), each output phase including a phase group of power cells connected in series; a voltage source power supply; and a bypass mechanism (650, 750, 850) comprising a backup power unit and a bypass contactor, where the phase groups of the power circuit are connected at the common coupling point, and where the backup power unit is mounted at the common coupling point.

The invention relates to the technical field of heat pump systems, and provides a frequency control method, device and equipment of a heat pump system and a storage medium, and the method comprises the steps that in response to a received refrigeration operation instruction, an environment temperature parameter and an exhaust temperature parameter of a compressor are obtained; based on the environment temperature range where the environment temperature parameters are located and the exhaust temperature interval where the exhaust temperature parameters are located, the frequency reduction amplitude is determined; and according to the frequency reduction amplitude, the operation frequency change of the compressor is controlled, and the frequency conversion driving module is cooled through the refrigeration module. According to the method, the frequency reduction amplitude is dynamically determined based on the multiple parameters, intelligent adjustment of the operation frequency of the compressor is achieved, reliable operation of the unit in the high-temperature environment is guaranteed, and the refrigeration energy efficiency ratio of the unit is effectively increased.

The invention relates to the technical field of elevator control, and discloses a variable frequency driving system for elevator control, the system comprises a dynamic speed regulation control end, a voltage frequency cooperation end, a harmonic suppression management end and a multi-stage voice alarm module, the dynamic speed regulation control end is arranged, and when elevator operation control is carried out, the voltage frequency cooperation end is matched with the harmonic suppression management end; a speed regulation and control curve is automatically generated based on the load state and the operation requirement, and the acceleration change process is optimized in the start-stop stage, so that the system can eliminate current impact during traditional power frequency start, stable start of a motor is ensured, load impact of mechanical transmission parts is reduced, and abnormal abrasion of equipment is avoided; voltage and frequency output characteristics are dynamically matched by adopting a closed-loop regulation technology, so that the system can automatically regulate power output according to actual load requirements, the defects of light-load energy consumption waste and insufficient heavy-load power of a traditional scheme are overcome, and efficient and stable operation under different load working conditions is ensured.

The invention relates to the technical field of agricultural harvesting equipment, in particular to an awn crushing, threshing and cleaning device of a highland barley combine harvester. Wherein the threshing cylinder is divided into a front end awn crushing section and a rear end threshing section, two sections of spike teeth are driven to rotate reversely through a coaxial reversing mechanism, a feeding auger and an awn crushing fan are arranged at the front end, and material conveying and preliminary wheat awn scattering are synchronously achieved; an anti-blocking and unblocking roller device is assembled on the outer side of the arc-shaped concave plate, and screen hole clamping objects are carded in real time; a top cover plate of the threshing cylinder is provided with a sectional type material guide plate, a hydraulic spike tooth assembly and a feeding quantity sensor, and the material accumulation working condition is dynamically adapted; the controllable fan is provided with a variable frequency drive and an adjustable air guide plate, and the air speed and the airflow direction can be adjusted according to working conditions. All the modules work cooperatively through the controller, threshing-awn crushing-cleaning integrated operation of highland barley is achieved, threshing thoroughness, awn processing efficiency and cleaning precision can be improved, manual intervention is reduced, and the requirement for large-scale highland barley harvesting is met.

The invention relates to an intelligent control method, system, equipment and medium for automatic discharging mining tunneling cutting picks, and the method comprises the following steps: monitoring the flowing state of coal rock slag in a spiral discharging channel in real time, collecting a channel pressure difference signal and a cutting pick vibration signal, and generating discharging state characteristic parameters; blocking risk quantification is carried out on the characteristic parameters, and a real-time blocking index is generated through weighted fusion calculation; based on the index, a cutting head rotating speed optimization adjustment amount is generated through a fuzzy reasoning mechanism; and finally, generating a rotating speed control instruction through dynamic amplitude limiting processing and sending the rotating speed control instruction to a variable-frequency driving system. By means of the method, real-time sensing and dynamic self-adaptive adjustment of the blockage risk of the discharging channel are achieved, the problem that the discharging channel is blocked due to coal rock property changes is effectively solved, the discharging efficiency and the stability of tunneling operation are improved, and the service life of cutting teeth is prolonged.

The invention discloses a terminal pressure feedback variable frequency pump set cooperative adjustment method. A terminal pressure sensing module, a central control module, a variable frequency driving module and a plurality of variable frequency pumps connected in parallel are included. The throttling loss of the valve is avoided through the precise feedback of the tail end pressure and the cooperative adjustment of the variable frequency pump set, so that the pump set always operates in a high-efficiency interval (the efficiency is improved to more than 85%), and the energy is saved by 30-50% compared with the traditional constant-speed pump system; and meanwhile, multi-pump cooperative adjustment avoids long-term operation of a single pump in a low-efficiency interval, and the energy utilization rate is further increased. And the tail end pressure stability is high, the tail end most unfavorable point pressure is monitored in real time, and the tail end pressure fluctuation range is controlled within + / -0.02 MPa in combination with quick response adjustment within 50 ms, so that the problem of insufficient or overpressure of a far-end user is effectively solved, and the user experience is improved.

The invention relates to a belt weigher weighing precision compensation method based on multi-sensor data fusion. According to the method, an original weighing signal and an electromagnetic interference signal of the belt weigher in a running state and a baseline noise signal in a no-load state are synchronously acquired, a feature vector is extracted based on the electromagnetic interference signal, and an intermodulation noise component in the weighing signal is predicted by using a nonlinear system identification model in combination with the baseline noise signal. Then, the noise component is subtracted from the original weighing signal through an adaptive cancellation algorithm to obtain a local compensation weighing signal, and finally, a final weighing signal is generated based on a plurality of local compensation weighing signals through a signal-to-noise ratio weighted fusion algorithm, so that intermodulation noise caused by electromagnetic interference generated by the variable frequency driver is effectively suppressed. The weighing precision and the anti-interference capability of the belt weigher are improved.

The invention discloses a control method and system for a comprehensive energy supply system of a double-source heat pump building, and relates to the technical field of heating, ventilation and air conditioning, and the control method comprises the following steps: collecting conductivity data, extracting a characteristic frequency component of the conductivity data, and judging the state of a phase change material through the characteristic frequency component; an adjusting instruction of the double-source heat pump is triggered according to the state of the phase change material, and a double-source heat pump energy supply mode is output; evaporation reference values are matched for different dual-source heat pump energy supply modes, the frequency of a compressor is adjusted according to the reference deviation, and a variable frequency driving signal is generated; dynamically adjusting compressor frequency and electronic expansion valve opening according to the variable frequency driving signal, monitoring inlet and outlet pressure difference of an evaporator after adjustment, and judging whether bypass valve shunting is carried out or not; a heat recovery channel is activated in bypass valve shunting, and energy recovery and energy supply regulation and control are completed. Through cooperation of conductivity characteristic frequency analysis and dynamic activation of the heat recovery channel, accurate judgment of the state of the phase change material and closed-loop regulation and control of energy flow are achieved.

The invention provides an anti-blocking control method and system for a spiral conveying device and the spiral conveying device, and belongs to the technical field of material conveying equipment. The method comprises the following steps: acquiring real-time current data of a spiral motor of the spiral conveying device; based on the quantitative relation between the preset filling rate and the current value of the spiral motor, the real-time filling rate of the materials in the spiral conveying device is determined according to the real-time current data; comparing the real-time filling rate with a preset anti-blocking threshold value; under the condition that the real-time filling rate is larger than or equal to a preset anti-blocking threshold value, it is judged that the blocking risk exists, speed increasing operation is executed, and the speed increasing operation comprises the step that an instruction is sent to the variable frequency driving module to increase the rotating speed of the spiral motor. And the active anti-blocking effect of the spiral conveying device is achieved, the risk of manual disassembly and blockage clearing is reduced, and a guarantee is provided for continuous operation of the whole system.

This utility model belongs to the technical field of material conveying equipment, and relates to a highly stable solid material feeding valve, including a valve body, a rotor, and a frequency converter drive assembly. The valve body has an inlet and an outlet at its upper and lower ends, respectively. The rotor is rotatably mounted inside the valve body and includes a central shaft and multiple V-shaped blades spaced apart along the outer circumference of the central shaft. The opening direction of the V-shaped blades is consistent with the rotation direction of the rotor, and a wedge-shaped plate is provided in the feeding groove formed between adjacent V-shaped blades. The frequency converter drive assembly is used to drive the rotor to rotate, and a direct connecting rod is provided between the frequency converter drive assembly and the valve body. This utility model realizes continuous material conveying, improves the reliability and stability of valve operation, reduces abnormal phenomena such as vibration and jamming during material conveying, and enables continuous conveying of bulk solid materials to designated areas for use by downstream equipment, meeting the requirements for safe, efficient, stable, and reliable solid material conveying.

This invention provides a dual-end driven long shaft system multi-order torsional vibration test platform and a torsional vibration identification and suppression method, relating to the field of long shaft system variable frequency drive technology. The platform includes two dual-winding drive motors respectively located at both ends of the shaft system, a load motor located in the middle, and a switchable shaft system connection structure, along with a dual-master, dual-slave cooperative control system composed of four drive frequency converters. This method achieves controllable excitation of multi-order torsional vibration by superimposing the load torque step and the frequency excitation source. It utilizes differential amplification and dual-channel filtering in the signal processing module to extract speed fluctuation characteristics, accurately identifying the critical speeds of each order in the system. For the identified torsional vibration phenomenon, a speed differential negative feedback algorithm is used to correct the torque command of the frequency converter, and the torsional vibration energy of the elastic transmission chain is offset by actively enhancing the system's electrical damping. This invention solves the problem of reproducing complex torsional vibration under safe and controllable conditions and verifying suppression strategies in ultra-large generator units.

The application discloses a circuit board and a variable frequency driver. The circuit board comprises a circuit board body and a solder pad arranged on the circuit board body. The surface layer of the solder pad on the circuit board body is a copper foil layer used for soldering electronic components. The solder pad has a tin stealing part and a tin trailing part. Both the tin stealing part and the tin trailing part are triangular, and the tin stealing part and the tin trailing part have a common side. The line between the top corner opposite to the common side of the tin stealing part and the top corner opposite to the common side of the tin trailing part is consistent with a first direction, and the extension line of the common side is consistent with a second direction. During the movement of the circuit board along the first direction, the solder tin first contacts the tin stealing part, so that the surface tension of the solder tin is uniformly distributed, and with the movement of the circuit board, the solder tin covers the pins of the electronic components and the solder pad to complete the soldering. Then, the tin trailing part guides the trailing of the solder tin to gather in the inside of the tin trailing part, reduces the tin connection phenomenon between adjacent solder pads, and reduces the safety hidden danger in the operation of the circuit board.

The utility model discloses an intelligent music playing and regulating device, and belongs to the technical field of pet music devices. Comprising a sliding plate, a rack is fixedly arranged in the sliding plate, a bottom shell is slidably mounted on the sliding plate and comprises a bottom plate and a mounting shell, the bottom plate is fixedly connected with the mounting shell, a variable frequency driving mechanism is mounted in the mounting shell, and a pet machine shell is fixedly mounted on the mounting shell; the pet machine comprises a pet machine shell, players are detachably installed on the two sides of the pet machine shell respectively, two lamp sockets are formed in the face position of the pet machine shell, and a rotating light projection device is arranged in the pet machine shell and comprises two light controllers. The pet music device has the advantages that the pet music device is provided with intelligent music, and the functions of mechanical intelligent movement and different light projection patterns can be realized at the same time.

The invention provides an anti-swing nonlinear control method and system based on a variable frequency driver, and relates to the technical field of ocean engineering equipment.The method comprises the steps that obtained system parameters of an offshore crane system are input into a nonlinear disturbance observer, and an aggregation disturbance observation value output by the nonlinear disturbance observer is obtained; determining mechanical energy, a state error vector and an anti-swing parameter of the offshore crane system based on the system parameters; processing the mechanical energy, the state error vector and the anti-swing parameter by using an energy storage function to obtain virtual energy; and inputting the aggregated disturbance observation value, the mechanical energy, the state error vector and the anti-swing parameter into a nonlinear anti-swing controller to obtain a control parameter which is output by the nonlinear anti-swing controller and corresponds to the virtual energy, so that the offshore crane system executes the control parameter. According to the invention, high-precision positioning of the load can be ensured, and swinging can be effectively inhibited.

The invention relates to the technical field of oil-submerged pumps, and provides an oil-submerged pump variable frequency drive circuit, a drive method and an oil-submerged pump system.The oil-submerged pump drive method comprises the steps that in response to a first current event and a second current event of a power loop of a motor drive circuit, first trigger time and second trigger time are collected through a sampling circuit; wherein the first current event indicates that the current reaches a preset first threshold value, the second current event indicates that the current reaches a preset second threshold value, the first trigger time is the trigger time of the first current event, and the second trigger time is the trigger time of the second current event; determining an oil-submerged pump driving mode based on the first triggering time and the second triggering time; wherein the oil-submerged pump driving mode is used for controlling an oil-submerged pump. According to the oil-submerged pump driving method provided by the invention, the problem of insufficient scene adaptability possibly caused by driving the oil-submerged pump in a single fixed operation mode in the prior art can be improved.

This application relates to the field of industrial air conditioning, specifically a temperature and humidity gradient sensing-based self-regulating industrial variable frequency air conditioning system. The system includes an outdoor heat exchange unit, a refrigeration unit, a multi-stage air duct delivery unit, a terminal airflow regulation unit, a distributed environmental sensing unit, and a core controller. The outdoor heat exchange unit is coupled to the refrigeration unit via a circulating refrigerant pipeline, and its core function is to exhaust the heat generated by the refrigeration unit to the outdoor environment to cool the circulating refrigerant. The refrigeration unit includes a compressor, a variable frequency drive motor to drive the compressor, and cold air outlets for generating cool air. This system aims to acquire temperature and humidity gradient information for different areas within the factory through a distributed environmental sensing network, and, combined with the system's own operational status data, to perform multi-stage coordinated closed-loop regulation of airflow distribution, airflow direction, and cooling power. This achieves efficient, uniform, and adaptive control of the temperature and humidity field within the factory space, and improves the system's overall energy efficiency and operational stability.

The invention provides an encryption identification method based on variable frequency driving. The method comprises the following steps: reading first identification data in a first storage unit; the first storage unit is a storage unit integrated in the first control module in advance; the first identification data are preset first identity data of the first control module and first encrypted data corresponding to the first identity data; verifying the first identification data to obtain a first verification result; reading second identification data in a second storage unit; the second storage unit is a storage unit integrated in the first driving module in advance; the second identification data are preset second identity data of the first driving module and second encrypted data corresponding to the second identity data; verifying the second identification data to obtain a second verification result; and determining whether the first control module is matched with the first driving module according to the first verification result and the second verification result to obtain a matching result. Mixed use of different frequency converter matching modules is avoided, and the product index performance is improved.

The invention discloses a double-closed-loop fuzzy PID control method for a variable-frequency speed regulation system of a coal mining machine. The method comprises the following steps: inputting an initial target rotating speed; generating a dynamic target rotating speed adaptive to the current working condition; the fuzzy PID controller adaptively adjusts PID parameters according to the speed error between the actual output speed of the motor and the dynamic target rotating speed, and the speed error is accurately converted into expected torque current; the PI current controller outputs a PWM control signal to the coal mining machine variable frequency transmission mechanism based on a current error between the actual torque current and the expected torque current of the motor; and the coal mining machine variable frequency transmission mechanism adjusts output voltage and frequency according to the PWM signal and drives the traction motor to adjust the rotating speed, so that the actual torque current of the motor accurately tracks the expected torque current, and the actual output speed of the motor is consistent with the dynamic target rotating speed. Therefore, rapid, low-overshoot and anti-saturation efficient operation of the coal mining machine under complex disturbance is realized.

The embodiment of the invention provides a frequency converter type selection method and device and a motor no-load test method. The model selection method comprises the steps that the selectable range of the rated current of a to-be-selected frequency converter is determined according to the rated voltage and the rated frequency of a motor and the rated voltage and the rated frequency of the to-be-selected frequency converter, and the rated voltage of the motor is larger than the rated voltage of the to-be-selected frequency converter; according to the selectable range of the rated current of the to-be-selected frequency converter and / or the estimated value of the maximum output power of the motor in the operation process of the variable frequency driving motor of the to-be-selected frequency converter from the rated frequency of the to-be-selected frequency converter to the maximum frequency of the motor, determining the selectable range of the rated power of the to-be-selected frequency converter; and on the basis of the optional range of the rated current and the optional range of the rated power of the to-be-selected frequency converters, selecting one to-be-selected frequency converter meeting the verification condition that the allowable minimum leakage reactance of the motor is not greater than the leakage reactance of the motor when the motor is controlled to operate by the to-be-selected frequency converter from the to-be-selected frequency converter pool as the selected frequency converter.

This invention discloses an AI-based predictive maintenance and closed-loop control system for industrial motor health, belonging to the field of motor monitoring and predictive maintenance. The system includes: a multi-dimensional high-frequency synchronous sensing unit for collecting motor operating parameters; a dynamic operating condition feature decoupling unit to eliminate the influence of speed fluctuations on signals under variable frequency drive through order analysis; an electromagnetic-mechanical coupling feature fusion unit to achieve deep fusion of current and vibration signals and construct a composite fault feature map; an artificial intelligence health prediction engine to output quantitative health assessment results based on a spatiotemporal sequence model; and an adaptive closed-loop control execution unit to automatically adjust motor operating parameters according to the assessment results, forming a complete link from sensing and prediction to closed-loop control. This invention solves the problems of high false alarm rate and difficulty in early fault identification under variable frequency operating conditions, achieving accurate assessment and automated closed-loop control of motor health status, significantly improving equipment reliability and intelligent operation and maintenance levels.

The application discloses a variable frequency heat pump unit and a heat dissipation control method. The variable frequency heat pump unit comprises a refrigerant circulation loop and a variable frequency driving module. The refrigerant circulation loop is connected to form a combination of a compressor, a heat exchanger, a liquid accumulator and a gas-liquid separator. The variable frequency driving module is provided with a heat dissipation pipeline. The outlet end of the heat dissipation pipeline is connected to the suction side of the compressor. The inlet end of the heat dissipation pipeline is communicated with the liquid storage cavity of the liquid accumulator through a first branch and a second branch. The first branch is provided with a cooling pipe section located in the gas-liquid separator. The outlet side of the cooling pipe section is provided with a first throttling device. The second branch is located outside the gas-liquid separator. The second branch is provided with a second throttling device. The opening degrees of the first throttling device and the second throttling device are adjustable and work cooperatively. The application can reduce the influence of heat dissipation on the main loop circulation by leading the liquid refrigerant in the liquid accumulator to dissipate heat for the variable frequency driving module, and can balance the heat dissipation efficiency and the unit performance.