60results about How to "Improve power quality" patented technology

The invention provides a network construction type bidirectional low-harmonic energy storage converter based on virtual synchronous control and an intelligent load identification method thereof, and belongs to the field of power electronics. The converter comprises a power module and a control module, wherein the power module is used for bidirectional conversion and output of electric energy; the control module comprises a virtual synchronous control module and a harmonic suppression control module, and the virtual synchronous control module adopts a virtual synchronous generator technology to realize active / reactive power bidirectional adjustment during electric energy bidirectional conversion of the power module and network construction level voltage and frequency support during electric energy output; and the harmonic suppression module is provided with a parallel QPR controller group (comprising a first QPR controller, a second QPR controller and a third QPR controller) which are used for processing third-time, fifth-time and seventh-time characteristic harmonics respectively and suppressing the characteristic harmonics of the electric energy output side of the power module. According to the invention, the dual modules are arranged in the control module, so that the cooperation of a network construction function and low harmonic output is realized, and the electric energy quality and the system operation stability are effectively improved.

The invention discloses a high-efficiency converter for adjusting the voltage of a power grid, and belongs to the technical field of power electronics. The converter comprises a first voltage regulation circuit, a second voltage regulation circuit, a filter circuit, a detection circuit and a control circuit. By detecting the amplitude difference between the power grid voltage and the load voltage, the control circuit automatically switches the Buck working mode or the Boost working mode, and stable alternating current output in a wide input voltage range is achieved. The invention has the advantages of compact structure, high efficiency, fast response, small harmonic wave and the like, and is suitable for industrial and civil occasions with large-range fluctuation and frequent power grid voltage.

The invention discloses a harmonic suppression and dynamic reactive compensation control method for an energy router, which is suitable for a micro-grid and a distributed energy access system. According to the method, three-phase current and voltage signals of an alternating current port of the energy router are collected, five-time and seven-time main harmonic components are extracted through fast Fourier transform, harmonic compensation current instructions equal in amplitude and opposite in phase are generated and injected into an inverter to be output, and active counteracting of main harmonics is achieved. Meanwhile, the bus voltage deviation and the change rate thereof are detected, a reactive current instruction is adjusted on line by adopting a fuzzy self-adaptive PI controller, rapid and smooth dynamic reactive compensation is realized, and the bus voltage is stabilized. Decoupling control of active / reactive and harmonic components is realized in combination with Park conversion, and virtual impedance is introduced to enhance system damping and harmonic suppression capabilities. Compared with the prior art, harmonic suppression and voltage support can be simultaneously realized under a single control framework, the response speed is high, the stability is high, and the method is suitable for high-performance grid-connected operation of the multi-port energy router.

The invention discloses an unbalance compensation method and system for an energy storage converter, and belongs to the field of power electronics and electric energy quality treatment. The system comprises a power instruction analysis module, a current reference generation module, a negative sequence current control loop module, a zero sequence control loop module, a positive sequence control loop module, a pulse width modulation module, a first conversion module and a second conversion module, the current reference generation module is respectively connected with the negative sequence current control loop module and the positive sequence control loop module; the third end and the fourth end of the negative sequence current control loop module are connected with the pulse width modulation module through the second conversion module; the third end and the fourth end of the zero sequence control loop module and the third end and the fourth end of the positive sequence control loop module are connected with the pulse width modulation module through the first conversion module. According to the method, the energy storage and compensation functions of the PCS can be seamlessly integrated under a unified control framework, so that the control system is greatly simplified, and the performance is remarkably improved.

The invention discloses an electric energy feedback collection and load peak suppression system for a wharf crane, and relates to the technical field of wharf power supply and distribution and energy management. Wherein the wharf crane comprises a quayside container crane (quay crane), a rail or rubber-tyred container portal crane (gantry crane) and the like, which are called cranes for short hereinafter. According to the system, instantaneous power, average power, peak duration and power increasing rate of a wharf power station, feedback power and feedback electric energy of a crane, capacity and charging and discharging parameters of an energy storage device, and electric energy quality indexes of a power grid are collected in real time; respectively calculating a peak impact index, a feedback absorption coefficient, a peak valley switching coefficient and a harmonic suppression coefficient, and comparing and analyzing with a preset threshold to generate a corresponding strategy; and integrating the results of the modules, carrying out unified scheduling on the energy storage device, and realizing power fluctuation compensation and stable output through a smooth scheduling strategy, thereby constructing an operation mechanism. According to the method, the instantaneous peak power of the wharf power station can be effectively inhibited, the feedback energy consumption capability is improved, the peak-valley scheduling economy is optimized, the electric energy quality is improved, and the safety, stability and energy efficiency of system operation are improved.

This invention relates to the field of power management technology, and particularly to an intelligent integrated power system and control method based on multi-source collaboration, including a main power module, a backup power cluster, an energy management unit, a voltage adaptation module, a status monitoring unit, a communication module, and a load interface. Compared to existing technologies that typically use a single type of battery pack as a backup power source, which suffers from slow response speed and difficulty in withstanding instantaneous high-power surges, this invention employs a heterogeneous energy storage system composed of parallel lithium battery packs and supercapacitor modules as the backup power cluster, and uses a bidirectional DC / DC converter for intelligent control. This solution fully leverages the different advantages of lithium batteries (high energy density) and supercapacitors (high power density and rapid response), enabling the system to provide both long-term backup power support and instantaneous high-power discharge, thereby significantly improving the dynamic response capability, power support reliability, and overall service life of the backup power source.

The utility model discloses a 700V direct current bus-based grid-connected and off-grid wind-light hydrogen storage coupling hydrogen production power supply system. The system comprises a photovoltaic power generation module, a wind power generation module, a hybrid energy storage module, a grid-connected module and a water electrolysis hydrogen production module. The photovoltaic power generation module and the wind power generation module are respectively connected to a 700V direct current bus through a DC / DC converter and an AC / DC rectifier, and power switch tubes in the DC / DC converter and the AC / DC rectifier all adopt SiC MOSFETs. When a power grid operates normally, if the electric energy supplied to the water electrolysis hydrogen production module by the wind and light power generation module is redundant, the redundant electric energy is stored in the hybrid energy storage module; and if the generating capacity of the wind power generation module and the photovoltaic power generation module is insufficient, the electric energy stored by the hybrid energy storage module is released to the water electrolysis hydrogen production module, so that efficient and stable operation of the water electrolysis hydrogen production module is ensured. When a power grid breaks down, the system operates in an off-network mode, and the wind and light power generation module and the hybrid energy storage module jointly provide electric energy needed by operation of the water electrolysis hydrogen production module.

The utility model relates to wind power generation technical field discloses wind power generation device, including support subassembly, wind wheel subassembly and power generation subassembly, wind wheel subassembly includes main shaft and impeller, and the main shaft fixed mounting is in support subassembly, and the impeller rotatablely installs on the main shaft, power generation subassembly includes first power generation unit and second power generation unit, and the stator of first power generation unit and second power generation unit all fixed mounting is in main shaft, and the outer rotor of first power generation unit and second power generation unit all are connected with the impeller fixedly, the utility model under the same wind force condition, first power generation unit and second power generation unit can work simultaneously, and the mechanical energy of impeller capture is more efficient, more fully converts into electric energy, effectively increases the overall power generation, improves the wind energy utilization efficiency and power generation efficiency, solves when the outside wind speed is at the low level, and the overall power generation of generator is insufficient.

The application discloses a low-voltage distribution network intelligent voltage-regulating energy-saving method based on multi-source data fusion, relates to the technical field of intelligent control of power systems, and comprises the following steps: S001, a transient separation collection band is arranged at an incoming line side, voltage signals and current signals are cut according to millisecond-level time particles, a sharp peak sketch is formed, and a tail of the sharp peak sketch is extracted; S002, the sharp peak sketch is spliced with a smooth running section to form a comparison band, and a resonance fingerprint set is extracted according to the tail of the sharp peak sketch and is used for marking transient resonance characteristics. The application constructs a resonance fingerprint set and a guardrail time axis, avoids misjudgment of transient sharp peaks, and prevents frequent switching of reactive power compensation; through a reactive power buffer bin and a multi-dimensional flexible adjustment means, dynamic compensation is realized, power quality is improved, and energy saving and system stability are taken into account.

The application provides a distributed offshore wind turbine control method based on a consistency algorithm, comprising: taking the distributed offshore wind turbine as a distributed intelligent agent, and obtaining total active power shortage of a plurality of intelligent agents; establishing an initial first adjacency matrix according to a communication relationship between adjacent intelligent agents, and adjusting the first adjacency matrix to obtain a second adjacency matrix; modifying an initial first Laplacian matrix according to the second adjacency matrix to obtain a second Laplacian matrix; establishing a target function taking maximization of a wind energy utilization coefficient of each distributed offshore wind turbine as an objective, and obtaining an output power increment allocated to each distributed offshore wind turbine according to the second Laplacian matrix, so that the distributed offshore wind turbine outputs corresponding output power; and the application can improve power quality and improve power control accuracy of the distributed offshore wind turbine.

The invention provides a PWM wave optimization method and system based on VIENNA rectifier single-period control. The PWM wave optimization method comprises the steps that three-phase input current is sampled; determining the position of the corresponding PWM wave high level in the switching period according to the current direction of each phase; the method specifically comprises the following steps: for each PWM output channel, according to a phase current symbol associated with the PWM output channel, selecting to place a high level at two ends or in the middle of a switching period; and based on the determined PWM high level position and the calculated duty ratio, generating and outputting a PWM driving signal used for controlling a VIENNA rectifier switch tube. According to the method, PWM generation logic is redesigned, a non-optimal voltage vector combination used in traditional synthesis is abandoned, and three vectors (namely vectors corresponding to three vertexes of a small triangle where a target vector is located) closest to the target voltage vector are adopted for synthesis; according to the optimization, on the premise that the switching frequency is not increased and extra hardware cost is not increased, output current harmonics are remarkably reduced.

The application relates to a power distribution network voltage control method based on a reactive virtual power plant, which comprises the following steps: constructing a double-layer collaborative regulation model based on discrete and continuous reactive regulation equipment in the power distribution network under the management of the reactive virtual power plant, and establishing power distribution network physical constraints; under the power distribution network physical constraint condition, day-ahead scheduling converts the optimization control of the discrete reactive regulation equipment into a first multi-agent reinforcement learning of a discrete action space strategy for solving, and generates day-ahead scheduling planning to be issued to an intra-day correction layer; under the conditions that the power distribution network physical constraints and the day-ahead scheduling plan are taken as boundary constraints, intra-day correction converts the control of the continuous reactive regulation equipment into a second multi-agent reinforcement learning of a continuous action space strategy for solving, and generates intra-day correction instructions; the continuous reactive regulation equipment is adjusted based on the intra-day correction instructions to obtain node voltage in the power distribution network; the node voltage in the power distribution network is fed back to the day-ahead scheduling layer to realize closed-loop collaboration of voltage optimization regulation.

A stepping type two-path active filtering control cabinet system comprises sampling current transformers 2TAa, 2TAb and 2TAc arranged in a capacitance compensation cabinet and sampling current transformers 1TAa, 1TAb and 1TAc arranged in an active filtering cabinet, and further comprises a plurality of active filtering modules connected in sequence, one end of each active filtering module is connected with the sampling current transformers 2TAa, 2TAb and 2TAc, and the other end of each active filtering module is connected with the sampling current transformers 1TAa, 1TAb and 1TAc. The other ends of the sampling current transformers 1TAa, 1TAb and 1TAc are connected with the sampling current transformers 1TAa, 1TAb and 1TAc; the system further comprises a centralized monitoring screen JKQ, and the signal acquisition end of the centralized monitoring screen JKQ is connected with the active filtering module. According to the application, current sampling is carried out on two paths of loads existing in a line, so that the active filtering module collects sampling current information; the centralized monitoring screen is used for performing centralized monitoring on the plurality of active filtering modules in the cabinet, thereby realizing step-by-step improvement of the electric energy quality of the line, improving the power supply reliability and protecting the equipment.

The application provides a static SVG device suitable for heavy load of a locomotive, relates to the field of railway power supply, and comprises a three-phase MMC converter, the three-phase MMC converter comprises three-phase bridge arms, each phase bridge arm is composed of an upper bridge arm and a lower bridge arm, the upper bridge arm comprises a plurality of cascaded half-bridge sub-modules, and the lower bridge arm comprises a plurality of cascaded half-bridge sub-modules, wherein the energy storage elements of the half-bridge sub-modules at least comprise super capacitors; further comprising: a voltage balancing module, which is used for determining the number of real-time input half-bridge sub-modules of the upper bridge arm and the lower bridge arm of each phase bridge arm, and determining the real-time input half-bridge sub-modules of the upper bridge arm and the lower bridge arm of each phase bridge arm based on the number of real-time input half-bridge sub-modules of the upper bridge arm and the lower bridge arm of each phase bridge arm; a network-forming voltage source control module, which is used for active control, reactive control and virtual impedance control, has the advantages of adapting to heavy load of a locomotive and improving the stability of power system operation.

This invention discloses a power regulation method and system for an intelligent traction power supply system; including: calculating real-time transfer power, and calculating compensation current in real time by combining power transfer error and negative sequence current; calculating current tracking value based on current inner loop command value and voltage synchronization signal; designing a feedforward-feedback composite controller to calculate feedforward compensation amount and feedback control amount respectively; calculating the total duty cycle of PWM modulation signal based on feedback control amount and feedforward compensation amount, and driving the railway power regulator to output the actual current value; the control method and system provided by this invention have low engineering implementation cost, are suitable for traction substation RPC application scenarios, and are easy to promote.

The invention discloses a power interface converter stability control method for a power-steam cogeneration system, and the method comprises the following steps: collecting a hydrogen energy storage state, a cogeneration unit operation state and an electric quantity, and constructing a comprehensive feasible region containing thermoelectric coupling constraint and ramp rate limitation; mapping an original power instruction into the feasible region and performing slope shaping to obtain a target power reference value; calculating an available energy margin and a fast power margin based on a physical boundary, and dynamically and cooperatively scheduling inertia and damping parameters of the virtual synchronous machine according to the available energy margin and the fast power margin; realizing grid-connected and off-grid seamless switching in combination with current margin gating logic; according to the invention, the system stability and the electric energy quality under complex working conditions are effectively improved.

The invention provides an auxiliary converter equipment control method and device in an offshore wind power DC system, and the method comprises the steps: carrying out the proportional-integral control of an offshore AC voltage frequency deviation through a frequency control module, generating a DC voltage reference value, assigning the DC voltage reference value to a DC internal potential of auxiliary converter equipment, and achieving the indirect control of frequency; meanwhile, a d / q-axis controller is used for controlling capacitor voltage and PCC point voltage deviation, a d / q-axis current reference value is generated, a harmonic suppression module is combined to compensate harmonic current, and finally a voltage reference value calculation module is used for generating a three-phase bridge arm voltage reference value by using a proportional resonance controller and a linear transformation matrix; and active / reactive decoupling control and frequency stability control are realized. The invention also provides a corresponding control device, electronic equipment, a storage medium and a program product, and can be applied to an open sea high-capacity wind power delivery system, so that the system oscillation risk is effectively reduced, the capacity demand of auxiliary commutation equipment is reduced, and the system stability and the electric energy quality are improved.

This invention discloses a method for suppressing current imbalance and power oscillations based on a virtual synchronous generator (VSG). First, a traditional VSG loop model is established and its parameters are tuned. Then, the positive and negative sequence components of the grid-connected voltage, filter capacitor terminal voltage, and grid-connected current are extracted using a time-delay cancellation method and transformed to a synchronous rotating coordinate system. An equivalent VSG grid-connected loop model is added to the traditional VSG model. The traditional active power and extended reactive power calculation methods are transformed to the synchronous rotating coordinate system, and a reference value for the grid-connected current that suppresses the second harmonic component of the power is derived. A PI controller is used to make the actual grid-connected current track the reference value, and the output modulated wave drives the inverter. This invention can simultaneously suppress the second harmonic oscillations of active and reactive power, improve grid-connected current imbalance and distortion problems, while retaining the active power frequency regulation, reactive power voltage regulation, and inertial support characteristics of the VSG, thus improving the stability and power quality of the new energy grid-connected system.

The application provides a primary frequency modulation method of a hybrid energy storage thermal power generating unit based on a flywheel energy storage device, and the method comprises the following steps: calculating a target power increment required for primary frequency modulation of the thermal power generating unit according to a frequency value of a power grid bus; collecting a real-time rotating speed of the flywheel energy storage device, and calculating a maximum power increment that can be output by the flywheel energy storage device in real time according to the real-time rotating speed; calculating a maximum power increment that can be output by a lithium battery energy storage device in real time according to a rated power value and a real-time power value of the lithium battery energy storage device; and dynamically allocating the power increments provided by the flywheel energy storage device, the lithium battery energy storage device and the generating unit in the primary frequency modulation in combination with the actual power regulation capabilities of the flywheel energy storage device and the lithium battery energy storage device and the rotating speed of the generator. The method involves the energy storage resources in the automatic power generation control of the generator unit, improves the frequency modulation effect and increases the frequency modulation response speed.

The invention discloses a low-pressure adaptive modulation method for a high-altitude variable-speed pumped energy storage transformation converter. The method comprises the steps of data acquisition, low-pressure modeling, insulation-power cooperative modulation, cooperative execution, state monitoring and circulation. The system comprises five core modules, namely a multi-parameter data acquisition module, a low-pressure characteristic modeling module, a low-pressure self-adaptive modulation module, a water turbine-converter cooperative modulation and execution module and a state monitoring and feedback module. The invention mainly aims to solve the three problems of high insulation breakdown risk, large power output fluctuation and mismatching with the working condition of an original water turbine caused by a low-pressure environment of a full-power converter when variable-speed water pumping energy storage transformation is carried out on a high-altitude small and medium-sized hydropower station. Dynamic adaptation of the full-power converter in'power generation-pumped energy storage 'dual-mode switching is achieved, meanwhile, the requirements of'low-cost transformation, simplified control and quick response' of small and medium-sized power stations are met, and safe and stable operation and electric energy quality of a transformed unit are guaranteed.

This disclosure provides a disturbance suppression method for grid-connected energy storage converters. By introducing an improved timing disturbance observer, it achieves rapid and accurate estimation of lumped disturbances such as grid voltage fluctuations and load abrupt changes. Combined with an adaptive sliding mode control algorithm, it dynamically adjusts the switching gain based on the sliding mode surface error, forming an observation-compensation closed-loop suppression mechanism. Simultaneously, relying on a multi-loop collaborative architecture consisting of voltage outer-loop sliding mode control, current inner-loop PR control, and capacitor voltage balance PI control, it achieves hierarchical suppression and decoupled control of multi-dimensional disturbances. Furthermore, it introduces a parameter adaptive optimization mechanism based on disturbance characteristics and device temperature, thereby significantly improving the dynamic response speed and steady-state accuracy of the system under weak grid conditions and complex operating conditions, reducing the DC voltage fluctuation amplitude, and comprehensively improving the system's stability, power quality, and wide-temperature-range operational reliability.

The utility model belongs to the technical field of medium-high voltage switches, and discloses a medium-high voltage quick circuit breaker, which comprises a static contact, a moving contact and an operating mechanism connected with the moving contact in a vacuum arc-extinguishing chamber, and the operating mechanism comprises a repulsive force mechanism comprising a rechargeable opening coil and a rechargeable closing coil, the repulsive force disc is arranged between the two parts and is pushed by electromagnetic force generated after the two parts are electrified respectively; the permanent magnet mechanism comprises a permanent magnet, a permanent magnet coil, a static iron core wrapping the permanent magnet and the permanent magnet coil, and a movable iron core capable of moving up and down relative to the permanent magnet, and electromagnetic force generated by positive and negative electrification of the permanent magnet coil eliminates or strengthens magnetic force of the permanent magnet, so that the movable iron core is far away from or close to the permanent magnet; and the driving shaft penetrates through the repulsive force mechanism and the permanent magnetic mechanism and synchronously moves up and down along with the repulsive force disc and the movable iron core so as to push the movable contact and the static contact to be switched on or switched off. According to the circuit breaker, electromagnetic repulsive force driving is combined with permanent magnet, so that the switching-on and switching-off speed is high, no bounce during switching-on is ensured, and the fault rate is extremely low.

This application provides a power supply method, device, system, medium, and product for a photovoltaic thermal energy storage system, relating to the field of photovoltaic power generation. The method obtains the state of charge (SOC) of the energy storage system and the output capacity of the shared bus capacitor inertia. When the energy storage capacity is sufficient and the bus inertia support capacity is normal, multiple power sources are used to power the system. However, under extreme conditions where the energy storage capacity is insufficient and the shared bus capacitor inertia support capacity decreases, the system no longer relies solely on electrical side resources. Instead, it combines the temperature of the heat transfer medium, the thermal storage state, and the heat demand on the thermal side to adjust the operation of the thermal side and output compensating power. Multiple power sources and thermal side compensating power are jointly injected into the shared bus capacitor, compensating for the power supply gap caused by insufficient energy storage resources and decreased capacitor buffer capacity. This improves the power supply reliability and power quality of the photovoltaic thermal energy storage system under multi-source fluctuations, sudden load changes, and extreme conditions, avoiding problems of power quality degradation and power outages.

This invention discloses a method for sensing the operational status of a distribution network, relating to the field of distribution network monitoring and intelligent operation and maintenance. The method includes: synchronous acquisition of multi-source ubiquitous data to construct a low-cost ubiquitous sensing network; edge-side data preprocessing and lightweight analysis; topology-adaptive multi-source data fusion: constructing a distribution network topology map based on neural networks and mining the spatial and temporal correlations of multi-source data; multi-dimensional quantitative assessment of operational status: constructing a multi-dimensional status assessment system; precise fault location and hierarchical early warning: fusing multi-terminal information to achieve precise fault location; and online model iteration and closed-loop optimization. This distribution network operational status sensing method, by employing a low-cost ubiquitous sensing network combined with dedicated sensors and non-intrusive monitoring, covers the entire distribution network—from source to grid to load to storage—solving the problems of large blind spots and high deployment costs associated with traditional sensing methods. It achieves effective monitoring of end nodes and branch lines, realizing the goal of full-area, blind-spot-free sensing.

The application relates to a power distribution network regulation method and device. The method comprises the following steps: acquiring feeder parameters on the power distribution network side and adjustable resource information on the user side; constructing a multi-objective function according to the feeder parameters and the adjustable resource information, wherein the multi-objective function aims to minimize three-phase current balance and minimize active power loss; solving the multi-objective function to generate an optimal regulation strategy, wherein the optimal regulation strategy is a target set value of each-phase active power in the next regulation period, and the optimal regulation strategy is used for optimizing the three-phase current balance and the active power loss distribution of the power distribution network. The method can realize accurate and optimized operation of the power distribution network.

The application particularly relates to a multi-energy hybrid energy storage system and a coordinated energy management strategy for an underwater vehicle. The system comprises a lithium ion battery, a super capacitor and a fuel cell using a proton exchange membrane, which are connected to a DC bus respectively. The method of the coordinated energy management strategy comprises: obtaining current motion parameters and current energy parameters of the underwater vehicle; inputting the current motion parameters, the current energy parameters and a desired speed into a load prediction model based on a BP neuron network to estimate a desired total power at a next time; determining a corresponding action strategy according to a current operation mode of the underwater vehicle, and performing power distribution on the desired total power based on the action strategy. The scheme can enable the hybrid energy system to perform smooth operation mode switching and optimal power distribution under different working conditions.

The application relates to the field of power grid stabilization, in particular to a system and method for improving the power supply reliability and power quality of a low-voltage distribution network, which comprises a first fast switching switch connected in series to a low-voltage power supply line and located upstream of a load, a battery energy storage device and a power generation device connected in parallel to the low-voltage power supply line downstream of the first fast switching switch. The first fast switching switch and a second fast switching switch can realize the rapid connection and disconnection of the power supply, the battery energy storage device can realize the short-term power supply of the power grid and the balance of the reactive current, three-phase unbalanced current and harmonic current, and the power generation device can realize the long-term power supply of the power grid, so that the entire circuit can stably operate whether the power supply is short-term or long-term.

The invention discloses an LCL integrated filter based on transformer leakage inductance multiplexing. The LCL integrated filter comprises a discrete inductor, a transformer side inductor and a filtering branch, the transformer side inductor is the inherent leakage inductor of the transformer, and the filter branch comprises a filter capacitor C. According to the LCL filter, the inherent leakage inductor of the transformer is multiplexed to serve as topological optimization of the power grid side inductor and the filtering branch, and the technical problems that a traditional LCL filter needs to be independently provided with the power grid side inductor, so that the size is large, cost is high, the inherent leakage inductor of the transformer is idle and wasted, instability is likely to happen under a weak power grid, and harmonic suppression cannot meet the grid connection standard easily are solved.

A kind of energy storage converter multi-machine parallel system stability analysis method, comprising: modeling and control of single PCS;Application of capacitor current feedback type active damping control strategy;Analysis of stability of single PCS under PI control;Mathematical modeling of multiple PCS parallel system;Establishment of parallel system norton equivalent circuit;Using logarithmic frequency characteristic curve, verify that active damping control can have better inhibitory effect on resonance peak of parallel system.Capacitor current feedback type active damping method can not only compensate resonance peak of parallel system, improve the stability of system, but also effectively reduce grid-connected current distortion rate, improve power quality.The stability analysis method for PCS multi-machine parallel system provided by the present application can be used for judging the operating state of parallel system, ensure the stable operation of system, and provide theoretical basis for parameter design of PCS controller.