184results about How to "Reduce current shock" patented technology

The invention provides a triphase variable-frequency power supply with high power and an operating method thereof, belonging to the technical field of variable-frequency power supplies. The variable-frequency power supply comprises a triphase grid input circuit, a rectifying circuit, an inverter unit, an output transformer, a direct-current (DC) bus monitoring circuit, an inverter driving circuit, an inverter output monitoring circuit, a transformer output monitoring circuit, an output switch driving circuit, a variable-frequency power supply output monitoring circuit, a digital signal processor (DSP), a keyboard and display circuit, a communication circuit, a vibration detection circuit and a protection circuit, wherein the triphase grid input circuit is connected with the rectifying circuit; the rectifying circuit is connected with the inverter unit; the inverter unit is connected with the output transformer and the DSP by the inverter driving circuit; the output transformer is connected with an output end of the power supply; and an input end and an output end of the output transformer, the output end of the power supply and the output switch are connected with the DSP. The variable-frequency power supply operates under the control of software.

The invention discloses a starting method of a full bridge and half bridge mixed type modular multilevel converter. The converter is subjected to alternating current uncontrolled charging firstly; when the voltage of each sub module of the converter reaches a working threshold value of a power-taking loop, an IGBT of a full-bridge sub module is triggered to enable the external characteristic of the full-bridge sub module to be consistent to that of a half-bridge sub module, and the system performs secondary uncontrolled charging to all sub modules through a starting resistor; after the secondary uncontrolled charging is completed, the voltage balance of the full-bridge sub module and the half-bridge sub module is realized through valve-control voltage-sharing control; and finally, direct current voltage control is started to complete starting of the converter. By adoption of the starting method, the condition of inconsistent charging voltages among different sub modules caused by inconsistency of charging characteristics among different sub modules can be solved, current impact caused by direct unlocking of the parallel serial type modular multilevel after uncontrolled charging can be lowered, and starting failure and protection lockout caused by uneven capacitive voltages of different sub modules can be avoided.

The invention discloses a black-start system and method for a wind and light power storage station. The black-start system comprises an energy storage power station, a controllable load, corresponding boosting circuits, an alternating-current power transmission circuit and a supply and demand balance management system, the energy storage power station comprises an energy storage battery and one or a plurality of energy storage current transformers and is connected with the alternating-current power transmission circuit by the boosting circuits, a plurality of energy storage current transformers are parallelly connected to form the energy storage power station, and the energy storage power station establishes alternating-current voltage of the power transmission circuit and frequency when serving as a black-start power supply of the system; the boosting circuits comprise boosting transformers and circuit inductors, and low-voltage alternating current outputted by the energy storage current transformers is boosted to a voltage grade meeting the requirements of the power transmission circuit by the boosting circuits; the controllable load serves as a control unit for balancing power in the system, energy can bi-directionally flow, and the controllable load is an energy storage system dispatching the power; the supply and demand balance management system is a coordination control pivot of the whole wind and light power storage station in the black-start process and monitors states of power transmission lines, sources, loads, stored energy and power grids in real time.

The invention discloses a low-voltage ride-through control method for a grid-connected inverter based on control mode switching. The method comprises the following steps: during normal operation of the grid, a grid-connected inverter adopts a VSG control mode, the d-axis and q-axis positive and negative sequence components of the grid voltage are acquired and the phase angle of three-phase modulated wave is output in a PR current control mode, and the phase angle is used to follow the grid-connected inverter in order to output a voltage phase angle; when the grid fails, the given values of the d-axis and q-axis positive and negative sequence components of the current are calculated, the given value of current under a static coordinate system is obtained through inverse rotation transformation, a PR current controller generates a voltage signal, and the grid-connected inverter is quickly switched from the VSG control mode to a PR current control mode; and at the end of failure, the grid-connected inverter is switched back to the VSG control mode from the PR current control mode at an appropriate time. A grid-connected inverter can be smoothly switched between control modes. The grid-connection impact current can be limited, and reactive power can be provided for the grid. Thus, low-voltage ride-through of a virtual synchronous generator under grid failure is realized.

The invention discloses a distributed-generation three-phase inverter smooth switch control method. The method includes smooth switch control over two parts from isolated island operation to grid-connected operation and from the grid-connected operation to the isolated island operation. A smooth switch control link is mainly composed of a phase-locked loop (PLL) and a switch. When an inverter is switched from the isolated island operation to the grid-connected operation, output voltage of the inverter is subjected to presynchronization by operating the switch, so that the output voltage and grid voltage of the inverter are synchronized, current impacting during grid connection is reduced, and smooth grid connection switch is realized; when the inverter is switched from the grid-connected operation to the isolated island operation, reference instruction controlled by current are gradually decreased to zero form current instruction current by operating the switch, off-grid operations have no effect on a system since the grid-connection current is dropped to zero before disconnection of the grid connection switch, the output voltage of the inverter cannot fluctuate, and off-grid smooth switch is realized. With the method, dual-mode smooth switch operation of the distributed generation system is realized.

The invention relates to a controller applied to a power grid side converter of a flywheel energy storage system. The controller comprises a simulation module, a current control module, a control system, the converter and an equivalent flywheel energy storage system model. The controller is characterized by simulating and analyzing the dynamic response performance of the power grid side power converter operating in rectification and inversion states and researching the correctness of the designed system and parameters. The topological structure of the power grid side converter is researched, a mathematical model of the power grid side converter is created, and a simulation model of the power grid side converter is constructed; according to the requirement of the balance of energy transmission between the flywheel energy storage system and a power grid, a current control technique for the power grid side converter, the control of active power and reactive power and a decoupling control policy are researched; a mathematical model of the post-coupling control system is given, control parameters are designed on the basis of an engineering design method, and a simulation program of the control system is constructed; a power grid voltage phase angle phase-locked loop technique and a PWM (Pulse-Width Modulation) control method for the converter are analyzed and researched, and an appropriate control method is chosen to meet the required total harmonic distortion index of alternating-current side power grid current.

The invention relates to a vacuum-pumping system for a wind tunnel body. The vacuum-pumping system includes a multi-level air cooled lobe pump assembly, a set of heat exchangers, a silencer, an overflow valve, and a check valve; the upper part of each air cooled lobe pump is provided with an air inlet, and the lower part of each air cooled lobe pump is provided with an air outlet; two sides of each air cooled lobe pump are provided with a cool air returning opening respectively, so that heat balance of a pump body can be maintained when the pump operates under a high pressure difference; when the pressure of an air inlet connected to the back end of the lobe pump system is greater than the discharge pressure of the lobe pump assembly, a part of pumped air can be directly discharged into the silencer via the overflow valve, and then is discharged into the atmosphere via the silencer; the other part of the pumped air is discharged into the atmosphere via the overflow valve and the silencer. Each vacuum heat exchanger of the system mainly includes a housing, heat exchanger tubes, and an anti-reflux valve. A PLC control technology and a frequency converter technology are adopted by the system, so that the vacuum-pumping system can automatically adjust the pumping speed according to the pressure of an entrance.

The invention belongs to the field of electric welding and particularly relates to an arc striking pulse peak current control electric welding machine and a control method thereof. The electric welding machine applies a low-frequency low-duty-ratio pulse current during short circuit, and an arc striking pulse peak current of the low-frequency low-duty-ratio pulse current ranges from a 30A welding current to a triplex welding current. Therefore, the arc striking pulse peak current can be higher than the welding current during the low welding current, and arc striking is facilitated; and the arc striking pulse peak current can be lower than the welding current during the high welding current, a short-circuit limit output circuit is cut off after arc striking in welding is successful, the welding current slowly rises from the minimum current to the welding current, and the striking current can be reduced by the means.

The present invention discloses a voltage dropping start generator regulator which comprises a rectification circuit, a voltage-stabilizing wave filter circuit, a setting potential circuit, a pressure sampling circuit, a setting pressure comparison circuit, a exciter current control circuit, a excitation source rectifying wave filter circuit and a exciter current regulating circuit, characterized in that the input end of the exciter current sampling circuit connects with the output end of the exciter current regulating circuit; the output end of the exciter current sampling circuit connects to the input end of a voltage dropping delay control circuit; the output end of the voltage dropping delay control circuit connects with the first input end of the setting pressure comparison circuit. The present invention is provided with simple circuit and reliable detection, can decrease startup current surge to the electricity generator by the dynamic load, make generator operation stable, drop down pressure when starts up, decrease current surge, effectively prevent the electricity generator from overloading, avoid engine from phenomenon like shutdown or rotate speed descend because of overload, and can be extensively applied on automatic excitation control of generator rotors.

The invention discloses a universal phase shift control method for transient DC bias of a dual-active-bridge DC converter, and the method focuses on the analysis from the perspective of triple phase shift because single phase shift and dual phase shift can be regarded as the special conditions of triple phase shift. The method comprises the steps that in the steady state period, the output sides of a primary side full bridge and a secondary side full bridge in the dual-active-bridge DC converter are named as VAB and VCD respectively; the primary side inner phase shift duty ratio is D1, the primary side and secondary side outer phase shift duty ratio is D2, and the secondary side inner phase shift duty ratio is D3. Supposing that the phase shift duty ratio suddenly changes from D1, D2 and D3 in the steady state to D1'', D2'' and D3'' in the next steady state and the converter is in a transient state, the on-off time of a switching tube in the first switching period after the duty ratiois suddenly changed is adjusted to meet a certain relation, and after the second switching period after the duty ratio is suddenly changed, the phase shift duty ratio is stabilized to be D1 '', D2''and D3 '', so that the transient DC bias of the converter can be eliminated. According to the invention, the current impact in the transient state can be reduced, and the dynamic response is accelerated.

The invention discloses a comprehensive electricity quality control apparatus for a low-voltage distribution network. The comprehensive electricity quality control apparatus comprises a control module, a voltage adjusting module and a reactive compensation module, wherein the control module respectively controls the voltage adjusting module and the reactive compensation module, the input lines of the low-voltage distribution network are connected with the output lines of the low-voltage distribution network through an overvoltage adjusting module and the reactive compensation module, and the voltage adjusting module is a voltage bidirectional adjusting module. Unstable voltage due to voltage fluctuation is effectively prevented by employing voltage compensation graded and bidirectional adjustment and the intelligent time-delay function of a composite switch, and current impact of a conventional contactor switching is reduced by a composite switch in a reactive compensation module. The system loss is minimized, and the safety of the apparatus is guaranteed. A man-machine interface is employed to facilitate operation and maintenance, and a remote transmission means is employed to further improve the monitoring capability on a power grid. The comprehensive electricity quality control apparatus for a low-voltage distribution network can be widely applied to the low-voltage distribution field.

The invention discloses a full-control energy consumption device which is used in a wind power flexible DC grid-connected system and comprises a full-control cascade module, a filter capacitor and anenergy consumption resistor. The full-control cascade module is used for slowing down the instantaneous current and voltage changes of an energy consumption device in operation after a fault occurs, and changing the absorption power of the energy consumption resistor through the output voltage of the full-control cascade module. The filter capacitor is used for inhibiting harmonic waves of the fault current feed in the energy consumption device. The dissipation resistor is used for absorbing transient energy in a system AC-DC fault period and protecting safe operation of the converter stationin the fault period. In one control period, the sum of the energy absorbed and released by the full-bridge cascade module is 0, and the transient energy is completely transferred to the energy consumption resistor. The invention relates to the configuration and structure of the energy consumption device, the voltage modulation method of the full-control cascade module, the parameter design of theenergy consumption device, the control strategy of the energy consumption device and the application of AC / DC fault transient energy dissipation. In addition, the energy consumption device does not increase the loss of normal operation of the system.

The utility model relates to a machine vision technique-based control mode for the automatic positioning of the pushing larry car. The utility model mainly includes the four steps as below: setting the target para-position area: each coking chamber of the coke oven can be arranged according to the oven number; the special numbers can be used for a couple of special para-position motions and the relevant oven no. status information will be displayed on the display unit of the man-machine interface to facilitate the operation; fixing the mode of operation for the velocity: the comparison can be made between the targeted oven no. and the present oven no, so as to ascertain the appropriate velocity run mode and the relevant parameters in the course of the run procedure; the operation can be made as per the selected velocity run mode and the relevant parameters; the machine vision apparatus is started up for stop operation so as to complete the para-position: after entering the phase of free slide velocity, the machine vision apparatus is started up to ascertain the accurate unoperated position to complete the para-position. The method is adpted to simplify the structure and improve the control level and the rate of the resource utilization as well as realize the high precision para-position.

This invention relates to one balance beam oil drawer induction motor saving control method and its device, which comprises the following steps: A, connecting induction operation parameters; b, induction motor entering power status to switch off from electricity network; c, induction motor and hollow excitation capacitor form alone island power system to collect induction motor operation parameters; d. induction motor entering automatic status to connect the electricity net, wherein, The control device comprises induction motor and alternating power circuit first switch elements and drive unit connected to the first switch elements, computer controller and data collection unit with inductance motor is connected to one hollow excitation capacitor.

The invention discloses a fan controlling means, which is used for a fan system comprising at least two fan sets and used for making one or more steps of speed regulation on the fan system, wherein, each of the fan sets at least comprises a fan and comprises the following steps: a fan set is selected to be regulated from the fan system; the speed of the fan set is regulated in a gradual way when two or more speed steps need to be regulated. The invention additionally provides a fan controlling device, which can cause the fan to effectively reduce the current shock during the operation, avoid the influence on the power supply system, reduce the noise and save the energy.

Provided is a three-phase bridge-type half-control rectification trigger circuit with the protection function. By means of the three-phase bridge-type half-control rectification trigger circuit with the protection function, pre-charging of a three-phase bridge-type half-control rectification circuit and regulation of a busbar voltage can be achieved. The three-phase bridge-type half-control rectification trigger circuit with the protection function mainly comprises a DSP controller, a Butterworth low-pass filtering circuit, a synchronous detection link device, a phase-shifting control chip and a drive circuit. It is achieved that the busbar voltage is regulated according to the duty ratio of PWM waves output by a DSP main control chip, and therefore the charging current of a capacitor is lowered during starting. Pre-charging of the three-phase bridge-type half-control rectification circuit is achieved, and the cost of a high-power inverter is lowered. Meanwhile, when the inverter operates, whether a three-phase incoming line current is an over-current and whether phase loss of a three-phase incoming line voltage occurs can be detected, a fault signal can be fed back to the DSP controller, and therefore safe operation of the inverter is guaranteed. The three-phase bridge-type half-control rectification trigger circuit with the protection function has the advantages of being flexible in control, good in charging effect, economical, practical, perfect in protection function and reliable in performance.

The invention relates to a soft start circuit of a converter. The main circuit of the soft start circuit comprises a DC (direct current) / DC converting circuit, a DC / AC (alternating current) converting circuit and a paralleling switch, wherein the DC / DC converting circuit comprises one or more mutually independent DC channels, at least one DC channel is a chopper DC channel on which a DC chopper circuit is arranged; the input end of the DC channel is a load connecting end, the output end of the DC channel is provided with a DC bus capacitor for forming the output end voltage; one or more soft start branches provided with soft start switches are connected between the load connecting end and the power supply connecting end of the paralleling switch; at least one of the one or more soft start branches is provided with a soft start resister, and the at least one soft start branch provided with the soft start resister corresponds to the chopper DC channel. By using the soft start circuit of a converter, the soft start current is small, the thermal design is easier, the paralleling impact current is small, and the soft start circuit can be widely used in the charging process of a DC load.

The invention provides an energy storage system, and the energy storage system comprises at least one energy storage unit cluster and a centralized monitoring system of the energy storage unit cluster, wherein the energy storage unit cluster is formed by connecting at least two energy storage modules in series; one energy storage module comprises an energy storage element group and a switch bridge arm, the switch bridge arm is composed of a master control switch and a bypass switch, one end of the master control switch is connected with the energy storage element group, the other end of the master control switch serves as a first input / output end of the energy storage module, one end of the bypass switch is connected with the first input / output end, and the other end of the bypass switch is connected with the second input / output end of the energy storage module; the energy storage unit cluster is coupled to the direct current bus through the DC / DC converter; and the centralized monitoring system is connected with the energy storage unit cluster through a control bus and is used for controlling the on or off of the main control switch and the bypass switch in any energy storage module in the energy storage unit cluster. According to the invention, the management flexibility of the energy storage system can be improved, the stability of the energy storage system is improved, and the applicability is higher.

The invention discloses a redundant output device comprising a DCS (distributed control system) master station, a first output module, a second output module and a redundant terminal module. One end of the DCS master station is connected with one end of the first output module, while the other end of the DCS master station is connected with one end of the second output module. The other end of the first output module is connected with a first end of the redundant terminal module, while the other end of the second output module is connected with a second end of the redundant terminal. A third end of the redundant terminal is connected with an instrument for controlling a scene. The first output module and the second output module same in structure are connected through a redundant channel for mutual information. By the arrangement, current stroke upon the instrument for controlling the scene is reduced during the course when a certain output module which is out of order is replaced by another output module, so that service life of the instrument for controlling the scene can be prolonged.

The invention relates to a coordination control method for a speed regulator and a converter in a working condition conversion process of a variable-speed pumped storage unit. Variable-speed pumped storage unit operation conditions are many, working condition conversion is frequent, the conversion process is complex, and reasonable working condition conversion control is of great importance to safe and stable operation of the unit. However, unlike conventional pumped storage units, the variable speed unit is commonly controlled by a governor and a converter. The relatively slow mechanical torque response characteristic of a guide vane-pump turbine system controlled by a speed regulator is not matched with the rapid electromagnetic torque response characteristic of a converter, and therefore working condition conversion control is more difficult. Therefore, the invention provides a corresponding flexible working condition conversion coordination control strategy which comprises four main stages of flexible self-starting, cut-in control, steady-state operation and cut-out control. In the working condition conversion transition process, the unit can safely, rapidly and softly achieveworking condition conversion by coordinating the speed regulator and the converter; all conversion stages are smoothly connected.

The embodiment of the application provides a method and device for controlling an inverter, and relates to the field of power technologies. The method is applied to a control component in a power system. The power system further comprises an inverter, a power grid and a grid-connected switch, wherein the inverter is connected to the power grid through the grid-connected switch. The method comprises the steps of: when the inverter is in an off-grid state, detecting the parameter of the output voltage of the inverter and the parameter of the grid voltage of the power grid; when the parameter ofthe grid voltage satisfies a first preset grid-connected condition, instructing the output voltage of the inverter to follow the grid voltage of the grid in order that an amplitude difference, a frequency difference and a phase difference between the output voltage of the inverter and the grid voltage of the power grid satisfy a second preset grid-connected condition; when the amplitude difference, the frequency difference and the phase difference between the output voltage of the inverter and the grid voltage of the power grid satisfy the second preset grid-connected condition, turning on thegrid-connected switch. The method can reduce the current surge when the inverter is switched from a off-grid mode to a grid-connected mode.

The disclosure provides a driving apparatus and a method for driving a semiconductor light-emitting device assembly. The apparatus includes: a driving unit configured to drive the semiconductor light-emitting device assembly; and a cycle by cycle control unit. The cycle by cycle control unit may include: a sampling circuit configured to sample a current instantaneous value of the driving unit or the semiconductor light-emitting device assembly; and an adjusting circuit configured to adjust an output of the driving unit when the current instantaneous value sampled by the sampling circuit is larger than or equal to a preset reference value. The driving apparatus and method for driving the semiconductor light-emitting device assembly may effectively reduce an inrush current on the light-emitting devices and have a lower cost.

The invention relates to an intelligent halogen headlight system. The intelligent halogen headlight system comprises dipped headlights with halogen bulbs, high beam lights, front fog lights, turn signal lights and an automatic control system. The automatic control system comprises a sensor set, a fog detector and a vehicle light control unit. A signal processing circuit of the vehicle light control unit receives vehicle running speed information, external environment illumination information, vehicle steering wheel turning angle information and external environment fog information, and converts all the received information into digital signals and outputs the digital signals to a microprocessor for processing. The microprocessor judges the obtained vehicle running speed V, an obtained illuminance value E, obtained vehicle steering wheel turning angles and external environment, and outputs control signals for a city mode, a turning mode, a road mode, a fog mode, a country mode and a highway mode correspondingly, so that the dipped headlights, the high beam lights, the front fog lights and the turn signal lights are driven in a constant-current mode to adjust light brightness. The intelligent halogen headlight system can improve road driving safety and driving comfort.

The invention discloses a soft start control method of LLC full-bridge converter based on variable duty cycle. The method is to control four MOSFETs on the primary side of the LLC full-bridge converter, as that signal of the upper and lower switch tube of the same bridge arm are complementary, at that same time, the duty cycle of the switch device is adjusted accord to the start-up time tr obtained according to the output voltage, so that the duty cycle of the driving signal of the switch device is gradually increased to a specified value according to a specified curve, so that the output voltage rises from 0 to a given voltage to reach a soft start. The method of the invention weakens the current impact in the start-up process of the traditional LLC full-bridge converter, reduces the output voltage overshoot, makes the circuit start more stable and reliable, and has higher engineering use value. The control method is reliable, the circuit is simple and easy to realize.

A multifunctional variable structure DC convertor disclosed by the invention comprises a DC power supply; an inverse circuit consisting of four switching tubes, two multipole-multithrow switches and two shorting bars, an insolating filter circuit; a rectification circuit consisting of four diodes, a multipole-multithrow switch and a shorting bar and an output filter capacitance. The circuit can obtain the DC convertor of the following five different functional structures by the different combinations of the three multipole-multithrow switches and the three shorting bars. When the input voltage range of the DC convertor is wide, current transforming can be realized by an optimal circuit topology according to the differences of the input voltages by converting a topology structure, thus improving the efficiency of the convertor, reducing the element redundancy of a system and reducing the cost.

The invention discloses a fuel cell hydrogen supply system control device and method and a hydrogen energy automobile, and relates to the technical field of hydrogen energy automobiles, the fuel cellhydrogen supply system control device comprises a hydrogen cylinder group, a plurality of hydrogen cylinder valves, a pressure reducing device, a hydrogen leakage sensor and a hydrogen supply controller, and the hydrogen supply controller is electrically connected with temperature sensors and pressure sensors of the hydrogen cylinder valves; the hydrogen leakage sensor is electrically connected with the hydrogen supply controller, the temperature sensor and the pressure sensor are respectively used for collecting temperature and pressure information of the corresponding hydrogen cylinder valve, the hydrogen leakage sensor is used for collecting hydrogen concentration information, and the hydrogen supply controller is connected with a fuel cell controller FCU through signals. The inventionfurther provides a hydrogen supply control method of the fuel cell system, accurate control over the hydrogen supply control device can be achieved according to the monitoring information, and then itis guaranteed that the whole vehicle-mounted hydrogen supply system is in a safe, reliable and stable running state.

The invention is suitable for the technical field of lithium ion batteries, and provides a lithium ion battery pack charging method and device and terminal equipment. The method comprises the steps of: obtaining voltage of each unit battery in a lithium ion battery pack and comparing the voltage; when the voltage of the unit battery with the minimum voltage value is smaller than first preset voltage, carrying out charging through first preset constant current until the voltage of the unit battery with the minimum voltage value is greater than the first preset voltage, and carrying out chargingthrough second preset constant current until the voltage of the unit battery with the minimum voltage value is greater than second preset voltage; and carrying out charging through third preset constant current until the voltage of any unit battery in the lithium ion battery pack achieves corresponding cut-off voltage, obtaining a current voltage sum of each unit battery as constant charging voltage, carrying out charging through the constant charging voltage and stopping charging when the charging current is decreased to a preset threshold value. According to the method current impact causedto the unit batteries with relatively low voltage in the charging process is decreased and the service life of the lithium ion battery pack is prolonged.

The invention discloses a LLC full-bridge converter soft start control method based on hybrid control, which comprises the following steps: S1, sampling output voltage by a voltage dividing method, thereby obtaining output voltage rise time, namely start time; S2, sampling output voltage by a voltage dividing method; 2, carry out frequency reduction control on that bi-directional LLC converter during startup, wherein the working frequency fs of the converter is set to twice the nominal frequency fr during startup, fs is gradually reduced during startup, and fs=fr at the end of startup; S3, adjusting the duty ratio of the switching device over time according to the obtained output voltage rise time while S2 is in progress, so that the duty ratio of the driving signal of the switching devicegradually increases to a specified value according to a specified curve. S4, after the driving signal generated by the mixed control of S2 and S3 is amplified by the driving module, the driving signal acts on the switching transistor in the main topology, so that the output voltage rises slowly from 0 to a given voltage to reach the soft start. The invention reduces the current impulse in the starting process, improves the dynamic characteristics of the output voltage, and makes the starting process more stable and reliable.

The invention provides an output voltage positive and negative polarity inversion method based on a modular multilevel converter. The method includes 1, constructing a modular multilevel converter module; 2, inverting the output voltage positive and negative polarities by adjusting the bridge voltage of the modular multilevel converter module; modulating the upper bridge voltage uu and lower bridge voltage ul of each phase, according to a bridge voltage wave image, into sine wave voltage symmetrical about a horizontal line U = UN / 2 vertically, and allowing that the LCC terminal output voltage ULCC = UN; modulating the upper bridge voltage uiu and lower bridge voltage uil of each phase into sine wave voltage symmetrical about a horizontal line U = -UN / 2 vertically, and allowing that the LCC terminal output voltage ULCC = -UN. Compared with the prior art, the method has the advantages that the operation requirements of LCC-HVDC and VSC-HVDC interface converters are met, and LCC-HVDC and VSC-HVDC interconnection implementation is benefited.

The invention provides a protection circuit for intelligently eliminating an impact of an UV lamp. The protection circuit comprises an MCU controller, a zero-cross detection module, a safety voltage detection module and an electronic switch, wherein the zero-cross detection module detects an approximate zero potential point of an AC power supply phase voltage of the UV lamp; the safety voltage detection module detects and outputs a safety voltage of a capacitor voltage of the UV lamp; the electronic switch is connected to an AC power supply loop of the UV lamp in series; and the MCU controller inputs a zero-cross detection signal of the zero-cross detection module and a safety voltage detection signal of the safety voltage detection module, and outputs a control signal according to the zero-cross detection signal and the safety voltage detection signal to control on or off of the electronic switch. The invention further provides a method for intelligently eliminating the impact of the UV lamp. The problem of the impact on an electronic component caused by a high current generated when the UV lamp is turned on can be fundamentally solved.