233 results about "Nameplate capacity" patented technology

A microgrid power generation system includes a plurality of generators having a plurality of different rated capacities and a plurality of distribution nodes, at least some of the distribution nodes being powered by the generators. A grid is formed by the distribution nodes, the grid includes a system frequency. A plurality of loads are powered by the grid through the distribution nodes, the loads have a power demand. A processor includes a plurality of efficiency bands, each of the efficiency bands being for a corresponding one of the generators and including a plurality of generator switching points based upon droop of the system frequency and the power demand of the loads. The processor is structured to operate the generators and the loads under transient conditions based upon the efficiency bands.

The invention discloses a method for group matching of power lithium-ion rechargeable batteries. The method comprises the following steps: one-step charge and discharge detection is conducted to the power lithium-ion rechargeable batteries and the batteries with capacities larger than lower limit capacity are taken as acceptable batteries; the acceptable batteries are charged to a state with 50-90 percent of rated capacity and the rechargeable batteries with acceptable voltage drop are sorted; the obtained acceptable batteries are fully charged and are connected in parallel for at least 4 hours to enable the voltage difference between any two rechargeable batteries to be less than or equal to 1mV; the obtained rechargeable batteries are connected in series to discharge, the voltage of each rechargeable battery during discharge is acquired and recorded, and the discharge is stopped when the voltage of any battery reaches cutoff voltage; and a voltage difference standard is set according to the number of series batteries required for group matching and the battery voltage at the moment of discharge cutoff, and the batteries with voltage differences within the preset range are matched into a group. Since the parameters of the batteries are measured and sorted under the simulated battery use conditions and the single rechargeable batteries with close characteristics are sorted, the quality of the group matching is improved.

Isolation IR heat lamp module and method of firing multi-zone IR furnaces for solar cell processing comprising lamps disposed in individual parallel channels in a reflector / insulator body to provide a cooling air channel surrounding each tube; the channels are covered with IR-transmissive plate material to isolate each lamp from adjacent lamps and the process zone. Cooling air is exhausted and recycled upstream for energy conservation. Lamp spacing can be varied and power to each lamp individually controlled to provide infinite control of temperature profile in each heating zone. For a spike zone, and in combination with downstream quench control and annealing zones, steep heating and cooling curves with very short dwell (sharp) peak temperature profiles permit faster throughput due to operation of the lampsm at essentially 100% rated capacity, at a 2× or greater heating and throughput rate without compromising lamp life, while producing solar cells with improved output efficiency.

The invention discloses a method used for rapid sorting of lithium ion batteries. The method comprises following steps: (1) three times of charge-discharge cycles are performed under a charge and discharge rate of 0.05 to 1.5C; (2) discharge capacity, total charge capacity, constant current charge capacity and constant current ratio of the third charge-discharge cycle are recorded; (3) the lithium ion batteries are allowed to stand for 12 to 72h; (4) open-circuit voltage and internal resistance are determined; (5) lithium ion batteries with a discharge capacity less than 1.05 times of rated capacity, and a constant current ratio less than 95% are eliminated, arithmetic mean values of the parameters of the rest lithium ion batteries are calculated, and the rest lithium ion batteries are selected based on following standards, A discharge capacity deviation ranges from +-0.5% to +-3%, B constant current ratio deviation ranges from +-0.2% to +-1%, C internal resistance deviation ranges from +-1% to +-10%, and D open-circuit voltage deviation ranges from +-0.03% to +-0.1%. Operation of the method is simple and convenient, cost is reduced, no extra equipment is needed, and sorting effect is obviously better than that of traditional sorting method.

The invention relates to a cluster analysis based lithium battery unit matching method which comprises the following steps of: (1) classifying battery units according to the types and the rated capacities of batteries, dividing the batteries with the same type and rated capacity in a group, and then furthering matching all battery unit sets with more than one battery unit; (2) selecting more than one factor combination of health status, self-discharge rate, internal resistance, open-circuit voltage, charging efficiency and cycle index for matching the battery unit sets; and after classification, completing matching of all battery unit sets with more than one battery unit, or further matching. The cluster analysis based lithium battery unit matching method can be used for comprehensively estimating all factors influencing the performance of the batteries, thus improving the consistency of the initial performance of the batteries; abd meanwhile, the probability of battery performance mutation in the using process of the batteries can be effectively reduced, the service efficiency of the battery units can be improved, and the service life of groups of battery units can be prolonged.

Isolation IR heat lamp module and method of firing multi-zone IR furnaces for solar cell processing comprising lamps disposed in individual parallel channels in a reflector / insulator body to provide a cooling air channel surrounding each tube; the channels are covered with IR-transmissive plate material to isolate each lamp from adjacent lamps and the process zone. Cooling air is exhausted and recycled upstream for energy conservation. Lamp spacing can be varied and power to each lamp individually controlled to provide infinite control of temperature profile in each heating zone. For a spike zone, and in combination with downstream quench control and annealing zones, steep heating and cooling curves with very short dwell (sharp) peak temperature profiles permit faster throughput due to operation of the lampsm at essentially 100% rated capacity, at a 2× or greater heating and throughput rate without compromising lamp life, while producing solar cells with improved output efficiency.

The invention discloses a capacity optimization configuration method for a hybrid energy storage system orientating optimization operation of a power distribution network. The capacity optimization configuration method comprises the steps of obtaining imbalance power between the optimal output and photovoltaic actual output when an optical storage system participates in operation of the power distribution network firstly, taking the imbalance power as a hybrid energy storage reference power, adopting ensemble empirical mode decomposition to decompose the imbalance power into a series of intrinsic mode functions, and performing recursion Hilbert conversion to obtain an instantaneous frequency-time curve of each intrinsic mode function separately; according to power type and energy type energy storage characteristics, determining crossover frequency by taking least aliasing of the instantaneous frequency-time curves as a principle, and stabilizing the high-frequency components and low-frequency components of the imbalance power by adopting power type energy storage and energy type energy storage respectively; and finally, by considering charging-discharging efficiency, state of charge and life cycle cost, a power type and energy type energy storage rate power and rate capacity economic optimal configuration scheme is proposed. Compared with a conventional method, new energy output can be compensated, consumption capability to new energy can be improved, and active participation to the optimization operation of the power distribution network can be realized.

The invention discloses a rapid container formation charging method for a lead-acid storage battery. The charging method is implemented through 27 charging and discharging stages, including eight times of discharging, one time of standing and one time of capacity checking and matching, wherein a maximum charging current is 0.15C<3> to 0.20C<3>, and a minimum charging current is 0.01C<3> to 0.05C<3>. The lead-acid storage battery is charged and discharged repeatedly, and a quantity of electricity charged each time is larger than a quantity of electricity discharged subsequently. Through adoption of the method, concentration polarization phenomena can be reduced greatly, and damages to crystal structures of active substances on a pole plate are reduced, thereby prolonging the service lifecycle of the lead-acid storage battery. As indicated by a detection performed according to specifications in GB / T18332.1-2009, the service lifecycle of the lead-acid storage battery adopting the method is greater than 450 times, and an initial capacity of the lead-acid storage battery is not less than 100 percent (counted by a rated capacity)

A battery delivers its rated capacity when the battery is below a temperature when the available battery capacity is limited. The battery includes a heating element, a temperature sensor, and a switch operatively connected to the heating element and temperature sensor and responsive to the temperature sensor for switching on the heating element and raising the temperature of the battery to allow the battery to deliver its rated capacity when a sensed temperature of the battery is below a temperature where available battery capacity is limited.

The invention provides a determination method and system of power grid wind electricity digestion capability. The method comprises the following steps of collecting load power of a power grid system within a certain period of time; collecting set data of the power grid system within the certain period of time, wherein the set data comprise a set type, a rated capacity, an upper limit and a lower limit of output of heating period, an upper limit and a lower limit of output of non-heating period and set creep speed; collecting foreign area electric power of the power grid system within the certain period of the time; adjusting the output of a set according to the upper limit and the lower limit of the output of the set; adjusting the output of the set according to spare restraint of upper adjustment and lower adjustment of a power grid; and determining the power grid wind electricity digestion capability according to the collected load power, the output, after being adjusted, of the set and the foreign area electric power. Through overall consideration of power balance of the power grid system, states of starting and shutting of each set and the range of the output under the condition of two load levels of peak and low, the multiple factors are uniformly optimized in a mixing integer planning model so as to obtain an optimal solution of the output of wind electricity.

The invention provides a grid-tied testing device for wind electricity and photovoltaic energy and a testing method thereof. The testing device comprises a power converter, a series connection transformer, a shunt transformer, an input breaker, an output breaker, a protective breaker, a first function change-over switch, a second function change-over switch, a third function change-over switch, a fourth function change-over switch, a by-pass switch and a digital signal processor (DSP) control and detection unit. An input end of the testing device is connected with a power grid, and an output end of the testing device is connected with a wind generating set or a photovoltaic generating station as a device to be tested. Deviation voltage or harmonic voltage output by the power converter and nominal voltage or fundamental voltage of the power grid are overlaid for achieving power grid adaptability requirements, and therefore the capacity of the power converter is far smaller than the rated capacity of the device to be tested. Due to the fact that the capacity of the power converter is reduced, the purposes that a system is low in cost, small in size, light in weight, small in heating value, high in reliability and the like can be achieved.

A battery pack includes a simple circuitry that improves the life cycle characteristic of the battery. The battery pack includes a plurality of cells connected in series. One of the cells is a lower rated capacity cell having a smaller capacity than the other cells. The lower rated capacity cell is disposed in a first tier of the plurality of cells from a negative terminal of the battery. Temperature and voltage of the lower rated capacity cell are detected to determine whether the lower rated capacity cell has reached the fully charged condition. When the fully charged condition is detected, charging of the battery is stopped. Similarly, based on the temperature and voltage detected, whether the lower rated capacity cell will soon be over-discharged is determined. If so, the use of the battery is stopped.

The invention relates to a power coordinated control method for a multi-terminal flexible DC transmission system. According to the method, a converter station with larger rated capacity is selected from a VSC-MTDC (Voltage Source Converter Multi-Terminal DC) system to serve as a main converter station, constant DC voltage control is performed on the main converter station, the other converter stations are divided into two groups, adaptive droop control and constant active power control are respectively performed on the two groups of converter stations, the main converter station performs regulation independently when the unbalanced power in the system is within a regulating range of the main converter station, and when the main converter station is fully loaded or out of operation, the redundant unbalanced power is regulated by a converter station adopting the droop control, the active power outputted by the converter station is automatically regulated according to DC side voltage changes caused by the unbalanced power so as to enable the system power to achieve a balance again. The power coordinated control method can avoid a phenomenon of out-of-limit voltage, reduce voltage fluctuations at the DC side and make full use of the active power capacity of the converter station. The method can effectively improve the control quality of the multi-terminal flexible DC transmission system, and meet control requirements of the system under different operating conditions.

The invention relates to a maximum power permeability calculation method for a distributed power supply in connection to a power distribution network. The maximum power permeability calculation method is characterized by comprising the steps that 1), for the maximum power permeability for the distributed power supply in connection to the power distribution network, the maximum power permeability of a medium-voltage distribution line is taken in consideration, and the maximum power permeability in a main transformer power supply region is taken in consideration as well; the maximum power permeability of the medium-voltage distribution line refers to a specific value between the maximum installed gross capacity of the distributed power supply and the maximum transmission capacity of the distribution line in the distribution line; the permeability in the main transformer power supply region refers to a specific value between the installed capacity of the distributed power supply and a main transformer rated capacity in the main transformer power supply region; and 2), the line intercepting amount constraint, the node voltage constraint and the busbar short circuit current constraint are comprehensively taken into consideration. According to the maximum power permeability calculation method, the different positions of the distributed power supplies of different types in connection to the power distribution network are illustrated and compared, so that the maximum power permeability of the distributed power supply in connection to the power distribution network is further optimized, and a technical scheme and calculation evidence for the distributed power supply in connection to the power distribution network widely and massively are provided.

The invention discloses a large-scale wind electricity and high energy-carrying load coordination control method. The large-scale wind electricity and high energy-carrying load coordination control method comprises the steps of defining the output of a wind power plant as a negative load according to the output short-term prediction curve and a load prediction curve of the wind power plant, overlaying an original load with the negative load and forming an equivalent load curve; according to the equivalent load curve, on the basis of considering the operation conditions of a wind power generating unit and a thermal power generating unit and the constraint conditions of the units, making generation plans of the wind power generating unit and the thermal power generating unit; according to the generation plan and the rated capacity of the thermal power generating unit, determining the spare capacity of the thermal power generating unit, adopting part of the spare capacity as the wind power pitch peak, and using another part of the spare capacity as the margin of the spare capacity; and when the wind power fluctuates, according to the spare capacity, used as the wind power pitch peak, of the thermal power generating unit, inhibiting the fluctuation of the wind power by adjusting the output power of the thermal power generating unit. The large-scale wind electricity and high energy-carrying load coordination control method has the advantages of being capable of achieving high output, large in application range and good in stability.

The invention discloses a method for estimating the state of health (SOH) of a battery. The method comprises: a rated capacity of a current electric core in a current environment is obtained by a temperature and charge and discharge rates; an SOC value of the current electric core is calculated; a corresponding residual cycle index is obtained; a current available maximum capacity of the electriccore is obtained; a resistance value REOL at the end of the life of the electric core and an internal resistance value of the electric core going out of the factory are acquired; according to a second-order RC ring model, an actual internal resistance of the electric core is calculated; a single healthy state of an ith battery at a current time is calculated; filter calculation is carried out on the single healthy state SOHi of the ith battery at the current time by a rolling average filter; a nominal available discharge electricity quantity in the battery system life cycle is obtained; and the SOH of the battery system is calculated. According to the invention, estimation of the state of health of the battery is carried out by integrating parameters of the single battery and the battery system; and because of consideration of influence factors like the temperature, the cycle number and the internal resistance for SOH estimation of the battery, the estimation result accuracy is improved.

The invention provides a distributed control method for an isolated micro grid. The method distributes a distributed controller for each distributed power supply, and only interactive voltage and frequency information between adjacent controllers are needed; a consistency algorithm evaluation is used to obtain average voltage and frequency of the whole network and is used for secondary optimal control; by optimizing reference voltage and frequency of droop control, each distributed power supply can output active power accurately according to a rated capacity proportional distribution, and system voltage regulation and frequency modulation are performed. Compared with the prior art, by using a sparse communication network without a center node, the method provided by the invention can realize the plug and play of the distributed power supply, and proportional control of power can be realized only through interactive voltage information; besides, the communication lines and communication traffics are less, the demand on the communication lines is low, and the reliability of the method is high.

An evaluation method for a system on a chip (SOC) of a charging station battery mainly solves the technical problem of charging station battery identity authentication and management and SOC evaluation algorithm of a charging station battery. The technical scheme is that: providing a charging station battery SOC nerve network evaluation method on the basis of standard model analysis of a charging station battery management scheme and a SOC evaluation method of a nerve network under the environment of an intelligent power grid based on type and life factor. A reading-writing module in a management system is used for reading inherent output information including a sole battery information identify (ID) number, a battery type, rated capacity and the like stored in an information chip of an ordinary battery, and rapid battery authentication under an united authentication system can be achieved. The charging station battery management system can use historic charging data of a battery from a network server through communication of a process layer network and a between station network of the charging battery so as to fit a curve of circulation time and electricity amount value, work out the life factor and judge the life state of the battery. On the basis that voltage, current and temperature serve as an input in the standard model of the nerve network, the battery type and life factor are added as input so as to achieve accurate evaluation of the charge state of the charging station battery.

The invention discloses an internalized charging method for a standby lead-acid battery. The total internalized charging amount is 5 to 7 times the rated capacity of the battery, and the total charging time is 95 to 105 hours. The maximal charging current is 0.15C10, and the minimal charging current is 0.03C10 through discharging twice, charging for six times and standing once. The method comprises the following steps of: placing the battery poured with acid in a circulator water bath within 5 minutes, and simultaneously connecting the charging circuit of the battery for charging; and starting a charger for charging when the temperature of the battery reduces below 40 DEG C, wherein the temperature of the battery is required to be below 50 DEG C in the whole charging process. The initial capacity is not less than 100 percent of the rated capacity by adopting the internalized charging method, and the recycling service life is longer than that of a tank formation battery and international requirements.

The invention discloses a depth control method for an energy storage power station participating in primary frequency modulation of a power grid, which is characterized in that a grid-connected inverter of the energy storage power station is equivalent to a synchronous voltage source with excitation control and speed regulation control, the energy storage power station adopts a control strategy ofa synchronous machine third-order model, and the frequency modulation depth of the battery energy storage power station participating in the primary frequency modulation of the power grid by settinga difference adjustment coefficient sigma<battery>% of the energy storage power station according to a flexibility index and a static frequency characteristic of the battery energy storage power station. The invention further discloses a contribution calculation method for the energy storage power station participating in primary frequency modulation of the power grid. The frequency modulation depth of the energy storage power station participating in system primary frequency modulation is controlled, so that the rated power, the rated capacity and the climbing rate of the energy storage powerstation are reasonably configured to stabilize the steady-state frequency of the system after primary frequency modulation in a reasonable range, the frequency stability and the voltage stability ofthe energy storage power station for supporting grid connection of the new energy system are improved, a contribution factor lambda is defined, and the importance of the energy storage power station in the power grid system to frequency modulation is analyzed.

The invention provides an island micro-grid distributed cooperative control method based on a hierarchical control strategy. The method comprises the steps of firstly constructing a hierarchical control structure into two structures of a local control hierarchy and a network control hierarchy; secondly, studying P-U / Q-omega droop control, wherein the P-U / Q-omega droop control is used as primary control of all distributed power sources and angular frequencies; then, introducing a communication network composed of all distributed power sources in a micro-grid in combination with a graph theory and a multi-intelligent-body theory; on the basis of the communication network, designing a novel Virtual leader-following consistency protocol which considers a time delay problem and using the protocol to complete secondary control of all the distributed power source voltages and the angle frequencies; finally, achieving reasonable distribution of active power by designing a current controller. According to the island micro-grid distributed cooperative control method based on the hierarchical control strategy, it is ensured that the distributed power source voltages and the angle frequenciesobtain a reliable control effect, and the effect that the active power is reasonably distributed according to the rated capacities of the distributed power sources is achieved.

The embodiment of the invention discloses a power battery life detection method and device, and relates to the technical field of a power battery. The method comprises the steps that a dynamic average is obtained according to driving condition data so that the simplified condition data of the driving condition data are obtained; a power battery discharge strategy is confirmed according to the current change data in the simplified conditions; constant current charging is repeatedly performed on the power battery on an electric automobile for multiple times, and discharging is performed according to the power battery discharge strategy; and if the current capacity of the power battery is attenuated to a percentage, which is less than a preset percentage, of the initial rated capacity of the power battery the cycling charge and discharge process, the number of cycles of charge and discharge of the power battery is confirmed and the number of cycles acts as the cycle life of the power battery. Problems of inaccurate detection results and poor experiment effectiveness when the power battery life is detected by a present constant current charge and discharge experiment mode without considering the actual driving conditions can be solved.

The invention provides a method for averagely controlling parallel power of inverters of a low-voltage micro-grid. A method of multiplying feeder line current and virtual complex impedances to obtain base wave virtual impedance voltage is used, output impedances of the inverters are designed to be ohmic and are matched with features of electrical parameters of a feeder line of the low-voltage micro-grid, and droop control output reference voltage is calculated and synthesized by a method of controlling power droop under the condition of ohmic equivalent output impedances; and a phase angle of the droop control output reference voltage is extracted and replaces a phase angle of common busbar voltage to perform dq / alpha beta coordinate transformation, and delay and distortion which are caused by the reason that the phase angle of the common busbar voltage is transmitted to a local controller from an integrated controller through low-bandwidth communication are avoided. When the method is used for a system for averagely controlling the parallel power of the inverters of the low-voltage micro-grid under the conditions that a nonlinear load exists, the feeder line impedances of the inverters are different, and the rated capacities of the inverters are different and the like, average control on the output power of the inverters can be realized, and circulation of the inverters can be restrained effectively.

The invention relates to a Charging-load space dispatching system for electric automobile and method therefor. The system comprises an electric vehicle ordered charging controller, a power dispatching unit and an electric vehicle dispatching center. Dispatching of the charging load space of an electric vehicle is achieved based on a charging request command, position information of the vehicle, and the residual electric quantity and the rated capacity of a vehicle cell, provided by the electric vehicle ordered charging controller, and also on a command about whether charging loads of all charging stations are uniformly distributed or not, provided by a power grid dispatching department. The problems of partial overloading and line congestion of power grids are solved.

The invention relates to a capacity configuration and operation optimization method for combination of photovoltaic energy storage and distributed energy. The method comprises the following steps: (1)collecting the basic data of a distributed energy system and thermodynamic and electric load data curves accurate to hours of one year; (2) configuring the capacity of energy conversion equipment inthe distributed energy system with the optimization objective of minimizing the total annual investment and operating cost of the distributed energy system; (3) determining the operation optimizationoutput curve of the distributed energy system; (4) determining an electric net load curve; (5) collecting the basic data of a photovoltaic energy storage system; (6) according to the basic data of thephotovoltaic energy storage system and the electric net load curve, optimizing the rated power of battery energy storage, rated capacity of battery energy storage and charging / discharging strategiesin the photovoltaic energy storage system with the objective of minimizing the annual total investment and operating cost of photovoltaic energy storage system. Compared with the prior art, the methodof the invention is fast and comprehensive and the result is accurate and reliable.

The invention discloses a parallel operation control method for power converters in a direct-current micro-grid. In the event that rated capacities of the power converters are not same and connection line resistances are not same, respective output powers still can be precisely distributed; therefore, the application range is enlarged; the anti-interference capability of a system is relatively high; the system still can work stably in the event of having relatively high communication delay; energy is mutually transferred between an energy storage unit and a direct-current bus by turning on and turning off a charging and discharging switch, such that steady voltage of the direct-current bus is kept; and the parallel operation control method is simple in principle and easy to operate.

A battery power amount calculation method comprises the following steps: inquiring a voltage power amount percentage table according to an open circuit voltage of the battery for obtaining a first power amount percentage of the battery, displaying the first power amount percentage on a set of display equipment, and eliminating the current value of a coulometer of the battery; reducing the numbers of inflow charges and outflow charges in the coulometer of the battery in a preset time period; calculating a difference between the number of inflow charges and outflow charges in the coulometer; converting the difference to micro-ampere hour; dividing the micro-ampere hour by rated capacity of the battery for acquiring an added / subtracted power amount percentage, and adding the first power amount percentage with the added / subtracted power amount percentage for obtaining a second power amount percentage; determining whether the average value of the current in the preset time period is smaller than a threshold value, when yes, returning and continuing inquiry, and otherwise, displaying the second power amount ratio. The invention further provides a battery power amount calculation system. The battery power amount of electronic equipment can be calculated through the battery power amount calculation method and the system.

The invention belongs to the technical field of power systems and particularly relates to an online measurement method for the true capacity of a transformer. The measurement method is disclosed by aiming at the conditions that the nameplate of the transformer can possibly lose in practical operation, the capacity of the nameplate does not coincide with the true capacity and the like. The online measurement method for the true capacity of the transformer has the measurement principle that the relation between the short-circuit impedance and the primary and secondary voltage current of the transformer is deduced through analyzing the equivalent circuit model of the transformer. In order to avoid performing online measurement on the high-voltage side signal of the transformer, an ideal alternating current power supply signal is utilized by the online measurement method for the true capacity of the transformer to replace the high-voltage side voltage of the transformer according to the characteristic that the high-voltage side voltage hardly changes along with load when the transformer normally runs; then, acquired secondary voltage and current signals and ideal power supply signals are simply calculated, and obtained signals are further calculated in the manner of linear fit, thus, the short-circuit impedance of the transformer to be measured can be obtained, and finally, the true capacity of the transformer is calculated by utilizing a short-circuit impedance method. By adopting the measurement method, the disadvantage of measuring the capacity of the transformer when a power supply is interrupted is overcome, and the safety of the online measurement technology is greatly improved.

The invention provides a hybrid energy storage capacity optimal allocation method for an AC / DC hybrid microgrid, and belongs to the field of the AC / DC hybrid microgrid. The hybrid energy storage capacity optimal allocation method comprises the steps: establishing a hybrid energy storage capacity two-layer optimal allocation model; power allocation verification based on set empirical mode decomposition; and allocation of the hybrid energy storage system capacity. The power commands of the lithium battery and the supercapacitor are obtained by the filter order. The energy storage life and the converter loss are comprehensively considered with the rated power and the rated capacity of the lithium battery and supercapacitor as the optimization variables and the annual integrated cost of the system as the goal, and an adaptive particle swarm optimization algorithm is applied to perform optimal solution so as to obtain the optimal annual integrated cost of the system and the corresponding rated power and rated capacity of the lithium battery and the supercapacitor. The problem of tie-line power fluctuation caused by wind-optical output fluctuation and load fluctuation in the AC / DC hybridmicrogrid can be solved.

The invention discloses a multivoltage level output variable-frequency power source and a control method thereof. A high-voltage charging circuit is connected with a phase-shifting transformer, which is connected with a frequency converter; and the frequency converter is connected with a contactor. Each phase of the frequency converter of the multivoltage level output variable-frequency power source adopts one basis current conversion chain, wherein the basis current conversion chain comprises a power unit and an electric reactor. A three-phase voltage enters into a phase-shifting input transformer through the high-voltage charging circuit, and supplies power for the power unit of the frequency converter after subjecting to voltage reduction of the phase-shifting input transformer. The power unit outputs a single-phase alternating voltage after subjecting to rectifying, filtering and inverting-inversion; and through changing a switch state of a contactor combination, a series connection way and parallel connection way of each basis current conversion chain are changed, so that outputs of rated capacities of different voltage levels are achieved. By adopting the multivoltage level output variable-frequency power source, the rated capacity outputs of multivoltage levels are achieved, each current conversion chain is connected with a sharing reactor, the parallel connection current-sharing effect is good, the circular current phenomenon generated when the current conversion chains are connected in parallel is avoided, the device and production cost is reduced.