42results about How to "Reduce current stress" patented technology

The invention provides a control method of a power conversion circuit, power conversion equipment and a power supply system. The control method can obtain a target inner phase shift duty ratio corresponding to the highest voltage matching degree according to the real-time direct-current voltage and the real-time alternating-current voltage, and obtain a reference outer phase shift duty ratio according to the real-time direct-current voltage, the real-time alternating-current voltage, the target inner phase shift duty ratio, preset target alternating-current power and power transmission constraint conditions. Adjusting a reference outer phase shift duty ratio according to the real-time alternating current and a preset target alternating current to obtain a target outer phase shift duty ratio, and obtaining a target switching frequency according to the real-time direct current voltage, the real-time alternating current voltage, the target inner phase shift duty ratio, the reference outer phase shift duty ratio, the target alternating current power and a switching frequency constraint condition, and controlling power transmission of the power conversion circuit according to the target switching frequency, the target inner phase shift duty ratio and the target outer phase shift duty ratio. According to the method, the transmission efficiency of the power conversion circuit can be improved, and the current stress can be reduced.

The invention provides a DAB optimization modulation method based on artificial intelligence and circuit transient behaviors, and the method comprises the steps: obtaining an analytical expression suitable for a DAB data driving model under the control of a full-mode UTPS through the numerical modeling of a circuit physical law and the sampling of a physical prototype, and employing an advanced artificial intelligence fitting technology, and obtaining a DAB optimization modulation model. The reference value of the optimal static modulation angle at the next moment is obtained based on the trained first artificial neural network, and the reference value of the transient phase shift angle is solved by using the transient phase shift angle correlation expression, so that the dual active bridge converter is controlled based on the obtained reference value of the static modulation angle and the reference value of the transient phase shift angle. According to the method, the dynamic behavior of each state variable of the circuit is accurately simulated, the dynamic performance and robustness of the system are remarkably enhanced, and the steady-state efficiency is synchronously improved.

The invention discloses a single-phase voltage-multiplying interleaving power correction circuit. The correction circuit comprises an alternating current power supply Ug, an inductor L1, an inductor L2, diodes D1 to D8, switching tubes S1 to S2, a capacitor C1, a capacitor C2, a capacitor C3 and a load RL, and the switched capacitor C3, the capacitor C1, the diode D7 and the diode D8 are respectively connected to form a switched capacitor circuit so as to form a voltage-multiplying structure. The advantages of the single-phase interleaving parallel technology and the voltage doubling rectifying circuit are combined, the multiple power converter units operate in an interleaving parallel mode, and voltage multiplication is achieved through the voltage doubling rectifying circuit. Compared with a traditional rectifier, the technology can effectively reduce the voltage stress of a power device, the input current THD and the size of an EMI filter through staggered parallel operation of a plurality of power converter units, thereby improving the overall performance and reliability of a system. Meanwhile, the voltage doubling rectifying circuit can be designed and adjusted according to requirements so as to adapt to different input and output voltage requirements.

The invention discloses a trapezoidal wave operation method of a T-type direct-current transformer. The method comprises the following steps: step 1, designing waveform constraint conditions of a multi-phase T-type direct-current transformer; 2, designing an alternating current waveform of the three-phase T-type direct current transformer; and 3, designing the optimal alternating current waveform of the three-phase T-type direct current transformer. The problems of low voltage and current utilization rate and high current stress caused by the fact that the T-type direct-current transformer adopts a sine operation mode are solved, the power capacity of the T-type direct-current transformer is remarkably improved, and the T-type direct-current transformer topology can be applied to high-voltage and high-capacity occasions. On the premise that the topological structure and the number of devices of the T-type direct-current transformer are not changed, the transmission power capacity of the T-type direct-current transformer is remarkably improved, the power loss of the devices is reduced, and the T-type direct-current transformer has great significance in topological application of an existing T-type direct-current transformer.

The invention discloses an interleaved parallel flyback micro inverter control method and device, and a readable medium. The method comprises the steps of obtaining a direct current voltage and a direct current of a photovoltaic module at an input end of a micro inverter, and performing maximum power point tracking calculation to obtain a reference output power; obtaining a power grid voltage instantaneous value and carrying out effective value calculation to obtain a power grid voltage effective value; calculating a grid-connected reference current effective value according to the reference output power and the grid voltage effective value; by setting a secondary side current overlapping factor and calculating and adjusting the switching frequency and the duty ratio, a secondary side current overlapping area is reduced to the greatest extent, and the peak value of the secondary side current can be reduced as far as possible, so that the current stress of a flyback diode and a power frequency flip circuit switching tube is reduced, and the grid-connected current quality is improved.

The invention discloses a multi-channel symmetrical CLLC topological structure and a power balance control method thereof, and the structure comprises a multi-channel symmetrical CLLC converter main circuit loop, a high-precision sampling module, a phase shift angle controller module, an input capacitor, an output capacitor and an equivalent load. And more efficient electric energy conversion and power management control are realized. According to the power balance control method, phase shift control is carried out on a secondary side switching tube control signal of a power loop through a fundamental wave analysis method, a forward gain formula under the control method is derived, and output gain regulation and control are carried out on converters with power errors in the multi-path symmetrical CLLC converters. And thus, the power balance control among the multi-path symmetrical CLLC converters is realized.

The present invention aims to provide a vehicle-mounted auxiliary power DC-DC converter, including an input capacitor C1, a Buck converter, a Boost converter, an output capacitor C2, and an LLC resonant converter; the Buck converter and the Boost converter are respectively composed of two branches, and the two branches of the Buck converter are connected in series with the two branches of the Boost converter in a one-to-one correspondence to form two groups of parallel Buck-Boost branch structures; the Buck-Boost branch structure is connected to the vehicle power battery in parallel with the input capacitor C1, and the Buck-Boost branch structure is connected to the input end of the LLC resonant converter in parallel with the output capacitor C2. The present invention also provides an integrated digital control method for a vehicle-mounted auxiliary power DC-DC converter. The converter overcomes the defects of the prior art and has the characteristics of a wide input voltage range, low conduction loss, and low cost.

The invention provides low-current stress non-isolated active back-end DC / DC converter equipment and a control method, and the equipment comprises a plurality of converter power modules which are connected in a manner that the front stages are connected in parallel and the rear stages are connected in series; each converter power module comprises a low-current stress non-isolation circuit and an active rear-end circuit; switching tubes of the low-current stress non-isolated circuit are jointly controlled by a controller, switching tubes of the active rear-end circuit are independently controlled, and a plurality of working modes exist in one period.

The application discloses a Sepic type power correction circuit based on a switched inductor, which comprises switching tubes S1-S3, diodes D1-D5, inductors L1-L5, capacitors C1 and C o The diodes D3-D5 and the inductors L4 and L5 form a switched inductor structure, and the voltage gain of the converter is D / (2-D). Compared with a conventional Sepic PFC converter, the Sepic type power correction circuit based on the switched inductor improves the step-down gain, ensures that the whole duty cycle range is in a step-down state, and has a larger duty cycle than the conventional Sepic PFC converter in the case of a high step-down ratio, thereby effectively avoiding the emergence of a limit duty cycle. The no-bridge structure can realize lower conduction loss. The original output diode is replaced by the switched inductor structure, so that the output current is continuous, and the output current can be filtered. All the switching tubes are common ground, and a lower-cost driving circuit can be used.

The application discloses a kind of based on single-stage grid-connected micro-reverse soft switching online real-time monitoring and closed-loop maintenance control method and system, mainly solve the problem of existing zero-voltage opening / non-zero voltage opening boundary difficult to judge and light load zero-crossing region loss soft switch leads to hard opening, its scheme includes: sampling the real-time state variable operated in single-stage grid-connected micro-reverse circuit, based on the sampled photovoltaic side voltage, photovoltaic side current, grid side voltage and grid side phase, respectively calculate internal and external moving phasor;Custom dead time and target level, according to the dead time and the sampled bridge arm commutation current, bridge arm commutation voltage and switching node voltage judge the soft switching state when commutation event k time;Based on the soft switching state, calculate the corrected internal and external moving phasor, output the driving signal of switch tube, to realize the soft switching online real-time monitoring and closed-loop maintenance of single-stage grid-connected micro-reverse.The application can improve the robustness of soft switching implementation, reduce the risk of hard opening, and can be used for soft switching control and energy transmission of single-stage grid-connected micro-reverse.

The application discloses a step-down converter and a power supply system. The step-down converter comprises first and second voltage division capacitors connected in series, and the two ends of the series connection are connected to the two poles of a voltage source. The half-bridge switching circuit comprises first and second upper and lower bridge arm switching modules connected in series, and the series connection of the first upper and lower bridge arm switching modules is connected in parallel with the first voltage division capacitor, and the series connection of the second upper and lower bridge arm switching modules is connected in parallel with the second voltage division capacitor. The step-down resonant circuit comprises first and second step-down resonant modules, the first step-down resonant module is connected in parallel with the first lower bridge arm switching module, and the second step-down resonant module is connected in parallel with the second lower bridge arm switching module. The primary side rectification output circuit is electrically isolated from the step-down resonant circuit and is magnetically coupled with the step-down resonant circuit. Thus, the circuit topology can reduce the switching voltage stress, improve the step-down capability, reduce the loss, and realize electrical isolation.

The application discloses a transient midpoint potential collaborative suppression method suitable for a network-constructed three-level T-type inverter and belongs to the technical field of power electronic converter control. In view of the problem that the three-level T-type inverter is prone to midpoint potential deviation in the process of grid frequency disturbance in a wind storage network-constructed scene, the application comprises the following steps: a low-frequency coupling model is established, in which active disturbance is transmitted to midpoint potential through d-axis current and midpoint current; event-triggered logic with hysteresis characteristics is constructed according to frequency deviation; a power shaping link is arranged at a source end, active instructions in an event window are subjected to second-order shaping, amplitude limiting and change rate constraint processing; a zero sequence extended state observer is arranged at a terminal side, online estimation is conducted on the generalized disturbance of a midpoint channel, and an additional compensation quantity is generated through a zero sequence port; and the source end power shaping and the terminal side zero sequence extended state observer are collaboratively put into the same event window, so that low-frequency disturbance entering the midpoint channel is weakened and the cumulative deviation of the midpoint potential is suppressed. The application can effectively reduce the midpoint potential peak value, suppress low-frequency energy accumulation, reduce transient peak current stress, and improve the operation safety and control stability of the network-constructed three-level converter under strong disturbance working conditions.

The application discloses a bridgeless Cuk PFC converter based on a switched-inductor-capacitor structure, which comprises switching tubes S1-S3, diodes D1-D4, inductors L1-L5, capacitors C1, C2 and C o The diodes D3 and D4, the capacitor C2 and the inductors L3 and L4 form a switched-inductor-capacitor structure. The original freewheeling diode is replaced by the switched-inductor-capacitor structure, so that the voltage gain of the converter is D / 2(1-D), compared with a traditional Cuk PFC converter, the converter realizes positive voltage output and improves the voltage reduction gain, and the duty cycle range in the voltage reduction mode is wider. Meanwhile, the bridgeless structure is adopted, so that lower on-state loss can be realized. The converter has continuous input and output currents, high power factor and high efficiency, and has rich application.

The invention relates to the field of dual-active bridge type converters, in particular to a wide-working-range multi-objective optimization method based on a dual-active bridge type converter, and the method comprises the steps: calculating a voltage conversion ratio through an input voltage and an output voltage, and determining an external phase shift angle ratio of a primary side H bridge to a secondary side H bridge of the dual-active bridge type converter according to a relation between the output voltage and a set value. And judging the working mode of the dual-active bridge converter according to the maximum transmission power and the current transmission power. And calculating a current effective value according to the voltage conversion ratio and the external phase shift angle ratio, taking the current effective value as an optimization target, and optimizing the current effective value and a current peak value by using an NSGA-II optimization function in combination with a working mode to obtain an optimal modulation scheme. In addition, based on the optimal modulation scheme, a trigger signal of each switching tube of the dual active bridge converter is generated in the DSP. According to the invention, the soft switching range can be expanded, the switching loss of the switching tube in the dual-active bridge converter is effectively reduced, and the overall efficiency of the converter is improved.

The invention belongs to a power electronic electric energy conversion technology, and particularly relates to a medium-voltage bidirectional direct-current converter based on a three-level resonance type DAB and a control method, and the medium-voltage bidirectional direct-current converter comprises N branch three-level resonance type DAB direct-current converter units and a modularized multi-level unit, the three-level resonance type DAB direct-current converter units of all branches are connected with a low-voltage direct-current bus side, and the modularized multi-level units are connected with a medium-voltage direct-current bus. A low-voltage port adopts a parallel structure of an NPC topology of a resonance type DAB to be matched with a direct-current low-voltage bus of the new energy motor, and the characteristics of low voltage and large current of the low-voltage direct-current bus are adapted; the current of the low-voltage direct-current bus is uniformly distributed on the input port of each resonance type DAB circuit, so that the current stress of a switching tube is reduced; a high-frequency isolation frequency converter is arranged in the three-level resonance type DAB structure, so that a low-voltage direct-current bus can be electrically isolated from a medium-voltage direct-current bus, and the electricity utilization safety of the low-voltage side is improved.

The invention discloses a method and system for improving short-time high-frequency energy storage efficiency, and belongs to the technical field of power system energy storage equipment. Phase shift control is improved, and adjustment is carried out in different time; on the basis of phase shift control, energy is fed back from a secondary side to a primary side by conducting a synchronous rectification switch tube in advance. According to the invention, the problem that a lagging bridge arm switching tube is difficult to realize ZVS is solved, the realization range of a soft switch is widened, and the switching loss is reduced; the working state of the switching tube is optimized, and the voltage and current stress in the switching process is reduced; according to the short-time high-frequency energy storage system, effective feedback of energy and lifting of resonance current are achieved, the resonance current at the turn-off moment of a lagging bridge arm switching tube is improved, ZVS is achieved, switching loss is reduced, and therefore the overall efficiency of the short-time high-frequency energy storage system is remarkably improved.

The invention discloses a coupling inductor bidirectional DC-DC converter and a control system, and belongs to the field of power electronic conversion, the converter comprises a low-voltage DC power supply VL, a low-voltage side capacitor C1, coupling inductors L1 and L2, power switch tubes S1 and S2, a high-voltage side capacitor C2 and a high-voltage DC power supply VH; the control system comprises a DSP, a high-voltage side voltage sampling circuit, a low-voltage side voltage sampling circuit, an inductive current sampling circuit and an isolation driving circuit. The circuit structure is small in element number, high in efficiency and small in size; the use of the coupling inductor obviously reduces the voltage stress and current stress of the power switch tube. In addition, the DSP peak current mode control mode provided by the invention has the advantages of high flexibility, strong anti-interference capability, fast external interface fault detection, fast response speed and the like.

The invention relates to a control method and system of a resonant converter and computer equipment, the method comprises three control modes of a primary and secondary side outer phase shift control mode, a frequency conversion control mode and a secondary side inner phase shift control mode, and the method comprises the following steps: detecting an output voltage signal or an output current signal, and calculating to obtain a feedback control quantity VFB; when the feedback control quantity VFB is in a first interval, a primary side and secondary side outer phase shift control mode is adopted, when the feedback control quantity VFB is in a second interval, a frequency conversion control mode is adopted, and when the feedback control quantity VFB is in a third interval, a secondary side inner phase shift control mode is adopted; the hybrid control method is simple, the gain adjustment capability of the resonant converter is improved, the frequency adjustment range is effectively narrowed, and the efficiency and the power density of the resonant converter can be improved.

This invention relates to a multi-resonant, multi-step-down ratio switched-capacitor converter, belonging to the field of power electronics technology. The invention addresses the technical problem of existing switched-capacitor converters struggling to achieve multiple fixed step-down ratios while maintaining high efficiency and high power density within the same topology. The invention includes: an input port; a switching network composed of fourteen MOSFET switches; a capacitor network composed of five flying capacitors; and first and second resonant inductors connected between the switching network and the output side. The converter is a single-stage topology, with the above components forming a single resonant network. By adjusting the switching timing, three fixed step-down ratios—8:1, 4:1, and 2:1—can be achieved within the same topology. The converter operates in open-loop mode, with the switching frequency matching the resonant frequency, achieving zero-current switching for all switches. The two-phase circuits on the output side operate in a staggered 180° manner to reduce current stress. The output side also includes first and second output ports connected in parallel, along with an output filter capacitor, which, after filtering, jointly supply power to the load.

The embodiment of the invention provides a frequency conversion and phase shift control method for an SSDAB converter for expanding the applicable power range of MBD-GaN, and relates to the technical field of converter control, and the method comprises the steps: obtaining an AC side voltage, an AC side current and a DC side voltage of a single-stage dual-active bridge SSDAB converter through setting an initial switching frequency; obtaining a voltage gain parameter and a normalized power parameter; obtaining a real-time operation interval according to a preset operation interval judgment mechanism; and taking minimization of a switch stress factor as a target to obtain a limited switch frequency, an inner phase shift quantity, an outer phase shift quantity and an outer phase shift angle, and inputting the values into a PWM module to generate a driving signal so as to complete frequency conversion and phase shift control of the SSDAB converter. The problem that the applicable power range of an MBD-GaN device is limited when an SSDAB converter is in a high-power working condition in the prior art is solved. And the effects of greatly reducing the current stress and the current effective value, reducing the switching loss and expanding the power application range are achieved.

The invention discloses a power supply module and a modular power supply. The power supply module comprises a multi-winding high-frequency transformer, a power frequency rectifier, a high-frequency converter, a diode rectifier bridge, an LC branch, a direct-current interface circuit and an equalization interface circuit, the first part is connected with a primary side high-frequency converter through an LC branch, the primary side high-frequency converter is connected with a power frequency rectifier, and the output of the power frequency rectifier forms an alternating current port; the second part is connected with a secondary side rectifier bridge through an LC branch, the secondary side rectifier bridge is connected with a direct-current interface circuit, and the output of the direct-current interface circuit forms a total direct-current port; and the third part is connected with the equalization interface circuit through an LC branch to form an equalization port. The size and the weight of the magnetic element are greatly reduced, and the power density of equipment is improved; a resonance technology is introduced to reduce switching loss and improve system efficiency; in addition, a three-phase four-wire alternating current port is constructed by matching with an independent AC accessory, and multi-type multifunctional electrical interfaces are provided.

The invention provides a multiplexed output synchronous rectification topology circuit and a power supply system, the multiplexed output synchronous rectification topology circuit comprises an input module, a switch tube Q9, a switch tube Q3, a voltage dividing unit, a transformer T4, a transformer T1 and an output unit, the input module is connected with the voltage dividing unit, the voltage dividing unit is connected with the voltage dividing unit through a primary winding of the transformer T4 and the switch tube Q9, and the output unit is connected with the switch tube Q9 through a secondary winding of the transformer T4. The voltage dividing unit is grounded through a primary winding of the transformer T1 and a switching tube Q3; the output unit comprises secondary windings of the two transformers, two output switch tubes and two output ports, one secondary winding is connected with the output port through the output switch tube, and a second end of the other secondary winding is connected with the output port; the secondary winding of the transformer T4 is connected with the output port through the output switch tube. The secondary winding of the transformer T4 is connected with the output port. The problems that in the prior art, a multi-output rectifying circuit is low in output efficiency and poor in coupling degree are solved.

The invention discloses a three-phase three-level ANPC series resonant dual active bridge DC / DC converter, belonging to the field of DC / DC converters, comprising: a control unit, a three-phase transformer, and two three-phase hybrid power device ANPC three-level circuits respectively connected to two sides of the three-phase transformer, a three-phase resonant network is connected between the primary side of the three-phase transformer and the three-phase hybrid power device ANPC three-level circuit connected thereto; the control unit is used to control the on and off of each switch tube in the three-phase hybrid power device ANPC three-level circuit, so that the neutral point level of the three-phase transformer is V dc / 6, 0 or V dc / 6, the voltage at the output of each half-bridge ANPC three-level bridge arm relative to the connection point of the two DC voltage-dividing capacitors is ‑2V dc / 3, ‑V dc / 2, ‑V dc / 3, 0, V dc / 3, V dc / 2 or 2V dc / 3, the resonant tank voltage of each phase is an eleven-level voltage. A three-phase three-level ANPC active bridge is designed in the DC / DC converter, so that the resonant tank voltage waveform is a multi-level voltage step wave that is closer to a sine wave, thereby reducing the reactive loss of the converter and the current stress borne by the switch tube.

The control method of a three-port isolated interleaved parallel structure converter belongs to the field of electric energy conversion technology. The present invention is to solve the problems that the transmission power of each port cannot be independently controlled and the efficiency is low in the existing control method of the three-port isolated parallel structure converter. It includes: decomposing the output current of the AC port in proportion to the expected transmission power of the two DC ports, subtracting the expected AC output current corresponding to the expected transmission power of the two DC ports and performing closed-loop control. The outputs of the closed-loop controller are respectively input into the optimized phase shift modulation strategy for minimizing the resonant current to obtain the internal phase shift angle of each converter and the external phase shift angle between each other, thereby realizing independent control of the transmission power of each port, sinusoidal waveform control of the output current of the AC port and high working efficiency. The present invention is used in a three-port isolated interleaved parallel structure converter.

The utility model discloses a kind of low ripple high gain composite Cuk-SEPIC direct current converters based on switching inductance module, belong to power electronic converter technical field, including switching inductance module, switching node module, the output module of SEPIC and the output module of Cuk, compared with conventional DCDC converter, switching inductance module is additionally arranged in converter main circuit, the output end of switching inductance module is connected with switching node module, the utility model passes through embedding switching inductance structure, can significantly improve voltage transmission ratio, satisfy low input high output scene demand, compared with transformer boost circuit, the utility model can reduce the voltage, current stress of switching device, reduce damage risk, prolong service life and improve system reliability, the optimized current path and energy conversion process of the utility model can reduce power loss, improve efficiency, and part circuit structure is simple, component is few, control is convenient, beneficial to reduce cost and improve response speed.

The present invention discloses a seven-level inverter circuit and a control method thereof. The seven-level inverter circuit comprises: an input DC power supply, a low-frequency pole-changing bridge arm, a high-frequency level selection bridge arm, an inverter-side inductor and a filter capacitor; by controlling the on-off of a switch tube, the inverter bridge arm composed of two bridge arms can output 0, V dc / 4, V dc / 2, V dc ,‑V dc / 4, ‑V dc / 2, ‑V dc Seven levels; the present invention controls the amount of charge to make the seven-level inverter circuit work in a mixed conduction mode (CCM and TPCM). The seven-level inverter circuit works at a fixed frequency and works in fixed-frequency critical continuous conduction in TPCM, which can significantly reduce the amplitude of the inductor current on the inverter side, that is, reduce the conduction loss of the seven-level inverter circuit, and effectively improve the low-frequency distortion of the output current.

The invention relates to a cascaded full-bridge MMC high-voltage hybrid energy storage device and a charging and discharging control method thereof.The cascaded full-bridge MMC high-voltage hybrid energy storage device comprises a grid-connected side circuit, a direct-current side switch, a discharging circuit and an energy storage side circuit, the grid-connected side circuit comprises a cascaded full-bridge MMC converter and an electric reactor, and the energy storage side circuit comprises an energy storage half-bridge power unit and an energy storage battery; one end of the cascaded full-bridge MMC converter is connected in series with a reactor and then is connected to a three-phase alternating current bus, and the other end of the cascaded full-bridge MMC converter is connected in series with a direct current side switch and then is connected in parallel with a discharge circuit; the discharge circuit comprises a discharge switch and a discharge resistor, and the discharge switch and the discharge resistor are connected in series; the energy storage half-bridge power unit is connected with an energy storage battery in parallel; the discharging circuit is connected with an energy storage side circuit in parallel; according to the invention, the power output capability, the energy density and the service life are improved, the direct current utilization rate of energy storage is improved, the circulating current is reduced, and the direct current loss of equipment is reduced.

The invention relates to the field of power electronic conversion, and particularly discloses a two-degree-of-freedom soft switching modulation method for a 4L-NPC dual-active bridge converter, which comprises the following steps: acquiring system parameters, determining a first control quantity D1 and a second control quantity D2, and dividing operation modes; generating a switch driving time sequence enabling the primary side to output four-level waveforms according to the D1 and the D2; establishing an inductive current model based on the time sequence, and calculating a transmission power and a key switch moment current value; and based on a calculation result, determining an optimal combination of D1 and D2 by combining a zero-voltage opening constraint and a current effective value minimization target, and generating a final driving signal. Through two-degree-of-freedom cooperative modulation, the soft switching range is effectively widened in a wide voltage gain range, meanwhile, the current peak value and the effective value are remarkably reduced, and the balance between efficiency improvement and control complexity is achieved.

The invention discloses a transmission system and a motor starting control method. The transmission system comprises a motor; one end of the speed regulator is connected with the motor, and the other end is disconnected with the load before the motor is started and connected with the load after the motor is started; the control system is used for controlling the operation states of the motor and the speed regulator; before the motor is started, the control system controls the motor to be powered off and controls the speed regulator to be powered on, so that the speed regulator drives the motor to rotate, and when the motor reaches the rated rotating speed, the control system controls the speed regulator to be powered off and simultaneously controls the motor to be powered on. According to the invention, the starting impact can be reduced, the influence on the motor and the power grid is reduced, the current demand during starting is reduced, the capacity of a power grid system is reduced, smooth starting can be realized, the motor is driven to rotate through the speed regulator, the motor generates no-load counter electromotive force, and the motor can be started more stably when electrified; the reliability and the stability of motor starting are improved, and the mechanical stress during motor starting is reduced.