890 results about "Dc bus voltage" patented technology

The invention relates to a self-adaptive intelligent power control method for an electric energy router in a photovoltaic power generation system. According to the method, key parameters of photovoltaic, energy storage and load are monitored in real time, a virtual power pool is constructed to quantify a multi-source power margin and dynamically distribute a priority sequence, energy storage output is dynamically adjusted in combination with a feed-forward compensation control strategy, frequency modulation deviation is periodically checked, weight optimization redistribution is triggered, and energy storage output is dynamically adjusted. Cooperative control of photovoltaic load reduction frequency modulation and DC bus voltage stability is realized, the multi-source cooperative frequency modulation response capability and the energy utilization rate are effectively improved, voltage fluctuation caused by power abrupt change is suppressed, and both the system operation economy and the power supply reliability are considered.

The invention discloses a DC bus voltage fluctuation suppression method of a renewable energy hydrogen production system, and relates to the technical field of renewable energy electrolysis hydrogen production. The method comprises the following steps: collecting system operation parameters in real time; bus voltage disturbance power is estimated based on a disturbance observer, and frequency decomposition is carried out; fusing the ARIMA model and the LSTM model to predict the load power, and calculating a prediction deviation; dynamically setting upper and lower limits of a bus voltage control interval according to the predicted deviation and the operation state; a multi-objective optimization function is constructed, bus voltage disturbance power, prediction deviation and a control limit value are comprehensively considered, and power regulation instructions of battery energy storage, a fuel cell and an electrolytic cell are solved; and executing power regulation control to realize bus voltage stabilization. The method can improve the grading response capability of voltage disturbance, the prediction accuracy of load power change, the adaptability of the control boundary and the overall operation stability of the system, and is suitable for the electric energy quality control of the hydrogen production system in a multi-source fluctuation scene.

The invention relates to the technical field of voltage control, in particular to a time-delay-containing uncertain AC / DC micro-grid DC bus voltage control method, which comprises the following steps: acquiring load change and DC bus voltage fluctuation data, calculating a load current change rate, analyzing the correlation between voltage fluctuation and load change, and performing voltage adjustment. And time delay characteristics in a load state are identified, voltage fluctuation uncertainty factors are identified, and the time delay compensation amount is adjusted to restore the voltage stability. According to the invention, by adopting linear and nonlinear time-delay compensation strategies, the problem of accuracy of time-delay compensation under different load conditions is effectively solved, various load fluctuations and voltage changes can be dynamically adapted, the problem of uncertainty of voltage fluctuations is solved, and the prediction of voltage fluctuations is optimized by dynamically adjusting the weight of uncertainty factors. The over-reaction to sudden voltage change is reduced, the voltage stability is improved, and the operation stability and the voltage regulation precision of the micro-grid are remarkably improved.

The invention relates to the technical field of bidirectional PCS converters, and discloses a VSG control method and device for a DSP numerical control high-frequency bidirectional PCS converter, and the method comprises the steps: carrying out the multi-signal classification of an output voltage, an output current, a DC bus voltage and a PWM modulation waveform of the PCS converter through a DSP chip, and obtaining a frequency spectrum feature vector; calculating a VSG parameter group based on the spectrum feature vector, inputting the VSG parameter group into a depth deterministic strategy gradient network for parallel training, and generating a VSG real-time control strategy; applying phase-locked loop compensation to the VSG real-time control strategy to obtain a PWM modulation signal after synchronous compensation; and carrying out real-time fault early warning on the PWM modulation signal after synchronous compensation, and carrying out seamless switching on a grid-connected and off-grid mode by adopting voltage feed-forward decoupling control to obtain a smooth transition control sequence. According to the method, the control period and the calculation load of the PCS converter under the high-frequency switching condition are reduced, and the control precision under the complex working condition is ensured.

The invention discloses a CPLD-driven IGBT short-circuit current dynamic monitoring method and system, and relates to the technical field of power electronics, and the method comprises the specific steps of S100 real-time data acquisition, S200 dynamic threshold calculation, S300 short-circuit state judgment, S400 rapid protection execution, and S500 fault data recording and uploading. Accurate and prospective judgment of the short circuit state of the IGBT is achieved, two stress parameters including the direct-current bus voltage and the junction temperature serve as independent variables, when the bus voltage rises, the voltage stress borne by the IGBT in the turn-off period is increased, meanwhile, the current peak at the short circuit moment is more remarkable, early warning is conducted in advance by dynamically lowering the threshold value, and therefore the short circuit state of the IGBT is accurately judged. According to the mechanism, the monitoring system does not simply respond to the occurred overcurrent, but can pre-judge the safety boundary of the device under the current working condition, so that intervention is implemented before the current really reaches a dangerous peak value, and a protection blind area under a severe working condition is effectively avoided.

The invention belongs to the technical field of equipment energy-saving control, and particularly discloses and provides an energy-saving control system based on a direct-current bus system, which comprises a direct-current bus framework module, an equipment state acquisition module, an equipment state analysis module and an energy flow control module. According to the method, the direct current bus voltage and the multi-dimensional operation data of the equipment motor are collected in real time, the motor power state space model is constructed by means of the Kalman filter, and the power sudden change probability of the future preset time period is accurately predicted. And meanwhile, an energy distribution strategy is dynamically adjusted in combination with the total power demand generated by the production schedule and according to the braking type and the power sudden change probability. The defect that dynamic power difference cannot be tracked through fixed threshold value feed-forward compensation in the prior art is effectively overcome, so that bus energy deposition is avoided, braking energy is distributed according to needs, meanwhile, it can be ensured that the braking energy can be recycled timely and correctly, and energy waste caused by misjudgment is reduced.

The invention belongs to the technical field of large-depth ground-to-air electromagnetic detection, and particularly relates to a light-weight high-power ground-to-air electromagnetic detection power supply system and method and a high-power vehicle-mounted power supply. Two paths of lithium battery units connected in parallel are adopted to provide short-time high-power emission current for a transmitter; the controller is used for acquiring a detection task set by the transmitter and setting a reference voltage according to the detection task; the voltage acquisition module is used for acquiring a direct-current bus voltage and comparing the direct-current bus voltage with a reference voltage to obtain a current modulation signal; and the controller is also used for acquiring the output current of each path of lithium battery unit and outputting a control signal according to the current modulation signal to compensate the output current of each path of lithium battery unit. According to the invention, the stability of a power supply system is realized when different instantaneous high-power outputs in a detection task in a high-power ground-air electromagnetic detection system are realized. When the output voltage and the sudden increase or decrease of the load current are adjusted as required, the stable output of the power supply voltage is realized.

The invention relates to the technical field of electric power operation and maintenance, in particular to a distributed optical storage unit cooperative scheduling control method and system, the method is applied to a distributed optical storage system comprising a plurality of optical storage units, each optical storage unit comprises a photovoltaic unit, an energy storage unit and a load unit, and is configured with a local unit controller. Comprising the following steps: collecting real-time operation data of an optical storage unit, and extracting local collaborative scheduling characteristics and a local DC bus voltage instantaneous fluctuation ratio from the real-time operation data; each unit controller inputs the corresponding local cooperative scheduling feature into a preset local scheduling strategy generation model, and outputs an initial scheduling action instruction set; and performing global voltage stability evaluation on the distributed optical storage system based on the local direct current bus voltage instantaneous fluctuation rates corresponding to all the optical storage units, and calculating to obtain a system voltage fluctuation index. The distributed local control capability and the global collaborative demand are organically fused, and the global voltage stability and the collaborative scheduling consistency are ensured.

A method comprises: in an onboard charger of an electric vehicle, providing i) a direct current (DC) to DC stage including a dual-active bridge, and ii) a DC link capacitor having a DC bus voltage; and dynamically regulating the DC bus voltage to improve zero voltage switching (ZVS) in the onboard charger.

The invention provides a transient current capability improvement control system and method of a wind and light power generation system. The system comprises a self-synchronizing voltage source control module, a junction temperature prediction module, a transient current improvement control module, a current instruction calculation module and a transient current precise control module. According to the invention, online observation of the junction temperature of the wind-solar converter power device can be realized, the maximum short-circuit current which can be output can be accurately predicted, the DC bus voltage, the switching frequency and the modulation strategy are adjusted when the power grid has a fault, the junction temperature of the power device is reduced, and the transient current endurance capability of the power device is improved. And the transient current is accurately controlled to limit the utilization of the transient capability of the power device.

A control system for an AC-DC converter includes a mixed-signal power controller and first and second gate drivers. The controller has a digital module and an analog module. The analog module has a current sensor generating a current sense voltage based on a sensed switch current. The digital module has a DC voltage sensor generating a DC sense voltage based on a DC bus voltage, and an AC voltage sensor generating an AC sense voltage and a binary polarity signal based on the AC voltage. The digital module induces the first gate driver to output first and second control signals for controlling a high-side switch and a low-side switch of a current shaping half-bridge based on first and second clock signals and the comparator voltage, such that an inductor current flowing through an inductor is proportional to a current command value.

The invention relates to the technical field of building electrics, and particularly provides a control method and system of an optical storage direct flexible system. The control method comprises the following steps: acquiring power load data of a target building within a preset time; acquiring illumination meteorological data in the preset time; obtaining a power load prediction curve according to the illumination meteorological data and the power load data; based on the power load prediction curve, constructing a control relationship between the direct current bus voltage at the grid-connected part of the optical storage direct-flexible system and the total grid-connected power; and based on the control relationship, performing power regulation according to the voltage change condition of the direct current bus. According to the invention, when the real-time power deviates from the predicted optimal load value, such as the inflection point, the optical storage direct-current flexible system can automatically deploy the power of the energy equipment connected to the direct-current bus. And system power response is completed according to the flexible capacity potential of the equipment, so that the system operation state tends to be economically optimal.

The invention belongs to the technical field of power electronics, and relates to an energy feedback high-power-factor air conditioner compressor driving system. Comprising a direct-current bus, a direct-current bus electrolytic capacitor, a motor driving circuit, a shutdown energy feedback circuit, a permanent magnet synchronous motor and a motor control module, wherein the two ends of the direct-current bus electrolytic capacitor are connected with the positive electrode and the negative electrode of the direct-current bus respectively; in the energy feedback control module for driving the combined switch device in the shutdown energy feedback circuit, the motor driving circuit and the shutdown energy feedback circuit, the second connecting end I of each phase of bridge arm is connected with the positive electrode of the direct-current bus, and the second connecting end II of each phase of bridge arm is connected with the negative electrode of the direct-current bus; the first connecting end of the phase bridge arm of the shutdown energy feedback circuit is connected with the phase power grid voltage through the phase filter inductor. The method can maintain the stability of the DC bus voltage, and reduces the influence of the power grid voltage fluctuation and the air conditioner compressor load fluctuation.

The invention discloses a balance control method for health states of multiple parallel energy storage units. Firstly, a communication-free state-of-health online estimation method based on a battery semi-empirical life model is deduced, the method does not need communication, is small in calculation amount, considers the rated capacity difference, is suitable for the dynamic degradation process of a battery, and is popularized to different rated capacities by introducing the concept of weighted ampere-hour throughput. Then, in order to meet the requirements of health state equalization, accurate current distribution and average direct current bus voltage recovery, a hierarchical control structure is established. Through coordination and cooperation among the main control layer, the secondary control layer and the communication layer in the hierarchical control structure, the provided strategy can realize the control targets of health state balance, accurate current distribution and average DC bus voltage recovery, and can greatly reduce the communication burden of the system.

The invention discloses a cooperative control system for an input-series output-parallel dual-active-bridge inverter, and relates to the technical field of power electronic converter control, an input voltage equalizing control IVSC loop is set for m-1 DAB sub-modules, and input voltage equalization of the DAB sub-modules is realized by adjusting phase shift angles of the sub-modules; an output voltage control OVC loop is set for the output DC bus voltage of the whole ISOP-DAB system to stabilize the DC bus voltage, a PIR controller is adopted in the OVC loop, and the resonant frequency is set to be twice of the fundamental frequency of the AC side, so that selective high gain is provided at the position, the frequency doubling fluctuation of the DC bus voltage is inhibited, and the frequency doubling fluctuation of the DC bus voltage is inhibited. According to the method and the device, the regulation quantity of the IVSC loop and the regulation quantity of the OVC loop are superposed to carry out cooperative control, so that the effective suppression of the frequency doubling fluctuation of the DC bus voltage and the automatic equalization of the power of each module are accurately realized on the premise of not increasing the hardware complexity.

The invention belongs to the field of new energy, and particularly discloses a direct-current bus voltage control method and system of a flywheel energy storage system. Comprising the following steps: if DC bus voltage is in a normal range, DC voltage forms a q-axis current reference signal after being adjusted by a PI controller, the q-axis current reference signal generates a q-axis voltage instruction signal after being adjusted by a current control loop PI, and a dq-axis voltage instruction value is generated through decoupling; if the current control loop slightly deviates from the normal range, parameters of a PI controller are adjusted, so that an integration link plays a leading role in control output, a virtual impedance link connected to the current control loop in parallel is adjusted, and a dq-axis voltage instruction value is generated; and if the voltage is seriously deviated from the normal range, a grid-side power signal is fed forward to a machine-side direct-current voltage control loop, virtual resistance in a virtual impedance link is adjusted, and a dq-axis voltage instruction value is generated. According to the invention, the control mode is automatically switched according to different conditions of the DC bus voltage by adopting a threshold-grading regulation and control strategy, and the adaptability to large disturbance is improved while the steady-state precision of the system is maintained.

A control system for a direct current (DC) microgrid is described. The control system includes a DC bus with a positive bus line and a negative bus line, DC battery circuits with a positive coupler connected to the positive bus line and a negative coupler connected to the negative bus line, switches including a control input terminal located in each DC battery circuit, a distributed generator circuit connected to the DC bus, a constant load power circuit connected to the DC bus, a computing device connected to each control input terminal, the DC bus, the distributed generator circuit and the constant load power circuit. The computing device includes an electric circuitry, a memory, and at least one processor to determine a DC bus voltage, determine the SoC of the DC battery circuits, generate PWM signals that control the DC bus voltage, and balance the SoC of the DC battery circuits.

The invention discloses a hydrogen fuel cell ship electric propulsion inertia self-adaptive optimization control method, which relates to the technical field of hydrogen fuel cell ship electric propulsion control, and comprises the following steps of: acquiring ship operation state data and ship internal power network fluctuation data in real time, preprocessing, extracting features, calculating a virtual inertia coefficient and a virtual damping coefficient, and calculating an inertia coefficient and a damping coefficient; generating a virtual torque instruction; obtaining a total power demand of the ship by using a torque rotating speed calculation method, and dividing the total power demand into high-frequency, intermediate-frequency and low-frequency ship power distribution instructions; through a virtual synchronous machine model, the actual power of the ship is output, the voltage of a direct-current bus and the power of a hydrogen fuel cell are monitored in real time, a dynamic compensation power fluctuation method is utilized, the operation state of the ship is regulated and controlled, and a voltage stability index is obtained; the ship propulsion inertia is adaptively optimized through a power regulation algorithm, so that the ship can better adapt to different working conditions, and the stability and safety of the ship are enhanced.

The invention relates to the technical field of bidirectional PCS, and discloses a bidirectional PCS converter multi-target power balance optimization method and system based on model predictive control. According to the method, real-time operation parameters are analyzed by using a first-order lag initial model, prediction of power disturbance in a plurality of control periods in the future is realized, power balance optimization is converted from passive response to active pre-judgment, and a linear time-varying prediction model is constructed, so that the real-time performance of power balance optimization is improved. According to the method, the evolution trajectory of the direct current bus voltage in a period of time in the future is predicted, the power balance optimization behavior is continuous and prospective through a rolling optimization mechanism of prediction, evaluation and preferential selection, and meanwhile, the three targets of ensuring voltage stability, reducing switching loss and suppressing current harmonic content are fused into power balance optimization, so that the power balance optimization efficiency is improved. The problems of control hysteresis and target singleness existing in a traditional control method are solved, and quick and accurate power balance control of the bidirectional PCS is realized.

The invention discloses a current distribution regulation and control voltage balance SOC optimization method, and the method comprises the specific steps: determining the type of a balance strategy according to the SOC difference between battery modules; according to the determined equalization strategy, the total cluster current of the system is distributed to each module according to SOC, and module reference current is generated and calculated; and finally, converting the module reference current into a bus voltage reference instruction, and controlling each module to track a voltage target to realize current distribution. According to the current distribution regulation and control voltage balance SOC optimization method provided by the invention, the target current is calculated, and then the current reference is converted into the bus voltage reference, so that the dynamic response speed and stability of the DC bus voltage are improved.

The invention relates to the technical field of logistics warehouse storage equipment, in particular to a speed reduction control method for a high-speed motor driven hydraulic system, which comprises the following steps: S1, the output torque of a high-speed motor is transmitted to a gear pump through a motor shaft, a planetary reducer and a planet carrier in sequence to drive the gear pump to work; s2, acquiring a three-phase current instantaneous signal and a direct current bus voltage signal, and performing preprocessing and frequency spectrum conversion to determine a current frequency spectrum; s3, in the current frequency spectrum, extracting an energy value in a preset frequency band with the meshing frequency and harmonic waves of the planetary gear as the center, and calculating to obtain a disturbance characterization value of the planetary gear; s4, determining a torque smooth adjustment coefficient according to the planet wheel disturbance characterization value; and S5, dynamically adjusting a dynamic response parameter of a torque control ring of the high-speed motor according to the torque smooth adjustment coefficient. The problems that in the prior art, a high-rotating-speed motor and a hydraulic pump are not matched in rotating speed, and mechanical disturbance is difficult to restrain are solved.

The application discloses a control method and device of a vehicle and a storage medium, and belongs to the technical field of vehicle control. The method comprises the following steps: in response to the fault level being a target level and the first detection result indicating that the engine and the ISG motor are in a series working mode, setting the charging target power of the power battery connected in the high-voltage loop to 0, and performing speed closed-loop control on the ISG motor with a speed threshold value as a target speed; in response to the actual torque of the engine being less than 0 and the direct-current bus current being less than a current threshold value, controlling the power battery to be disconnected from the high-voltage loop, performing speed closed-loop control on the engine and voltage closed-loop control on the ISG motor; and supplying power to the traction motor (TM) motor by the ISG motor. The DC bus voltage can be stabilized in the case that the power battery is disconnected, so that the TM motor can stably drive the vehicle to safely travel in the case that the power battery fails.

The invention discloses a single-phase voltage stabilizing device and a control method and system thereof. Compared with a traditional single-phase full-bridge PWM rectifier and a single-phase full-bridge inverter, the single-phase voltage stabilizing device has the advantages that one bridge arm is reduced, the device cost is lower, fewer devices are needed, fault nodes are correspondingly reduced, and the reliability is higher. The problem of control coupling of a grid-connected input side and an inverter output side is caused due to the fact that one bridge arm is shared, the inverter output side voltage is given to be associated with a grid side, the phases of the inverter output side voltage and the grid side are synchronized, then pulses of the shared bridge arm are naturally decoupled, and the output sinusoidal voltage is obtained. Meanwhile, due to the full-bridge PWM rectification control mode adopted by the grid-connected input side, the grid-side power factor can be 1, and the grid-side current is sinusoidal, so that green grid connection of the device is realized; the inverter output side tracks the network side voltage and introduces the direct current bus voltage as negative feedback, so that the stability of the output voltage is ensured, the stable single-phase voltage output is finally obtained, and the quality of the power supply electric energy in the substation is improved.

The invention relates to the technical field of power systems, and provides an efficiency optimization method and device for a power distribution system, electronic equipment and a storage medium, and the method comprises the steps: monitoring the real-time operation parameters of the power distribution system in real time, and dynamically analyzing the corresponding voltage fluctuation characteristics; performing voltage stability judgment based on the voltage fluctuation characteristics, and performing voltage adjustment on the power distribution system after a voltage adjustment mode is determined according to a voltage stability judgment result; performing optical storage collaborative optimization on the power distribution system through a multi-objective collaborative optimization strategy, and determining optimization parameters; performing load grading regulation and control on the power distribution system according to a preset priority, and determining regulation and control parameters; and generating a control instruction based on the voltage adjustment mode, the optimization parameter and the regulation and control parameter, and performing closed-loop control and efficiency optimization on the power distribution system based on the control instruction. Through a dynamic voltage hierarchical control architecture and a multi-target collaborative optimization strategy, the DC bus voltage in the optical storage DC flexible power distribution system is fast and stable, and the overall efficiency of the system is effectively improved.

The invention discloses a charging and discharging control method, control system and equipment for a two-way battery energy storage inverter, and the method comprises the steps: detecting a DC bus voltage, comparing the DC bus voltage with a target value, and generating a bus voltage error signal; inputting the error signal into a voltage outer loop controller, and outputting a total current given value of the system; acquiring a first path of battery charge state value and a second path of battery charge state value in real time; a current distribution strategy is dynamically selected; when the state-of-charge values are all higher than or lower than the target SOC, a proportional distribution strategy is executed; when the SOC value of one path is larger than the target SOC and the SOC value of the other path is smaller than the target SOC, a forced equalization strategy is executed; and distributing a current given value into independent current to be input into a corresponding current inner ring, and generating a PWM signal for driving a switch tube so as to realize that proportional distribution is adopted for a same-direction state to avoid overload and forced equalization is adopted for a reverse state to realize energy transfer, thereby prolonging the service life of a battery.

The invention belongs to the field of brushless doubly-fed motor control, and particularly discloses a low-bus-capacitor brushless doubly-fed direct-current power generation system direct-current voltage ripple suppression device which comprises a brushless doubly-fed direct-current power generation system, a machine-side converter control system and a direct-current voltage ripple suppression control system. The machine-side converter control system is connected with the machine-side converter and is used for controlling the direct-current bus voltage and suppressing harmonic voltage of a first target number of times of the direct-current bus voltage by adopting a control winding harmonic current compensation method; the direct current voltage ripple suppression control system is connected with the direct current bus and is used for separating harmonic voltage of a first target number of times of the direct current bus voltage and obtaining a harmonic current reference value of a second target number of times of the control winding; the active suppression of the direct-current bus voltage ripple is realized by integrating the harmonic voltage and the harmonic current reference value of the direct-current bus voltage. According to the invention, the system power density is ensured, and the electric energy quality is improved.

The invention discloses a phase voltage reconstruction method and device of a permanent magnet synchronous motor, a computer program product and a rotor position observation method and device.The phase voltage reconstruction method comprises the steps that three-phase PWM duty ratio signals and direct-current bus voltage of an inverter are collected, and ideal phase voltage is calculated through the duty ratio signals and the direct-current bus voltage; and dynamically correcting the error of the ideal phase voltage based on nonlinear characteristic compensation of IGBT / SiC. And on the basis of voltage reconstruction, a back electromotive force adaptive controller and a permanent magnet synchronous motor rotor position observer of an orthogonal phase-locked loop, full-speed-domain high-precision position estimation is realized by fusing a phase voltage reconstruction algorithm and expanding dynamic tracking capability of an EMF model and a QPLL, performance defects of a traditional method under low-speed and dynamic working conditions are overcome, and high-precision position estimation is realized. And the CPU resource consumption is high.

The invention discloses a multivariable model predictive control method for a photovoltaic inverter grid-connected system, which comprises the following steps of: establishing a mathematical model of an inverter under a rotating coordinate system, and setting a discrete mathematical model on the basis of traditional model predictive control to obtain a predictive value of output current; and taking the predicted value, the current error at the sampling moment and the error of the direct current bus voltage as control factors of the value function, and seeking the minimum solution of the value function to achieve the optimal control effect. According to the multivariable model predictive control method for the photovoltaic inverter grid-connected system, through the steps, the photovoltaic grid-connected response efficiency can be improved, the total harmonic distortion rate can be reduced, the stability and the anti-interference performance of the direct-current bus voltage can be enhanced, the grid-side current can be controlled at a lower total harmonic distortion level, and the effect is obvious.

The invention belongs to the technical field of power grid control, and relates to a transformer area flexible interconnection system three-phase imbalance control method and device and a medium. Taking the transformer area converter controlled by the PQ control algorithm as a target transformer area converter; collecting a first control parameter output by an active power PI controller of the target transformer area converter; based on the upper and lower limits of the voltage target value of the DC bus, performing amplitude limiting setting on the first control parameter of the target transformer area converter to obtain the voltage target value; subtracting the voltage target value from the actual voltage value of the direct-current bus, inputting the difference value into the PI controller, and outputting a second control parameter of the target transformer area converter; taking the second control parameter as a direct-axis current target value, subtracting the direct-axis current target value from a direct-axis current actual value, and taking the difference value as the input of a direct-axis current PI controller; and controlling the target transformer area converter based on the voltage modulation signal output by the PQ control framework. The scheme can effectively improve the power supply reliability of the power distribution area and stabilize the DC bus voltage.

The invention discloses a power control method, system, equipment and medium for a modular multilevel converter, and belongs to the technical field of power electronics and power system application, and the method comprises the steps: collecting the bridge arm current, the sub-module capacitor voltage, the DC bus voltage and the AC side power of the modular multilevel converter; calculating a power error according to the AC side power and a power reference value, and calculating a sub-module capacitor voltage error according to the sub-module capacitor voltage and a voltage reference value; constructing a Lyapunov function comprising a plurality of control targets, wherein the Lyapunov function comprises a power error term, a sub-module capacitor voltage error term, a circulating current suppression term and a total energy balance term; and determining a control law on the basis that the Lyapunov function meets a stability condition, and controlling the modular multilevel converter according to the control law. According to the method, the coupling control problem of multi-terminal direct current system power distribution and sub-module energy balance is considered and improved.