Output Power Control Research Articles

A study of automatic output power control methods for stand-alone photovoltaic power generation systems

Abstract The conventional power generation system’s output power automatic control structure is generally unidirectional, and the control coverage is small, leading to the increase in the random error obtained in the final test. Therefore, the design and research of this article are proposed. According to the current control demand, the generation system shall be stabilized first, and the power compensation shall be calculated. The multi-step mode shall be adopted to improve the control coverage and design the multi-step automatic control structure. According to this, it is constructed, and the automatic control processing is realized using jump balance. The test results show that compared with the traditional DFIG-DRWT system power output automatic control method and the traditional three-phase asynchronous generation system power output automatic control method, the random error finally obtained by the designed independent photovoltaic power station output power automatic control method is relatively effective. This indicates that the application effect and coverage of the designed power automatic control method are high, that controllability has been significantly improved, and that control flexibility has also been strengthened.

Output Power Control Strategy for Omnidirectional Wireless Power Transfer System Based on Maximum Mutual Inductance Information Estimation

Output Power Control Strategy for Omnidirectional Wireless Power Transfer System Based on Maximum Mutual Inductance Information Estimation

Research on Reactive Power Optimization of Synchronous Condensers in HVDC Transmission Based on Reactive Power Conversion Factor

With the rapid development of high-voltage direct current (HVDC) transmission systems, the coupling between AC and DC grids is becoming increasingly close. Voltage disturbances in the grid can easily cause commutation failures in the DC system, threatening its safe and stable operation. The new generation of synchronous condensers (SCs) and modified synchronous condenser units are powerful reactive power support devices widely used in large-capacity DC transmission systems. To maximize the voltage support and commutation failure suppression of SCs, this paper proposes improvements in the initial operating state of SCs, using the Shanxi–Wuhan HVDC receiving end in the Hubei power grid as an example, to better support the HVDC commutation process. Additionally, a reactive power output optimization strategy for SCs is proposed, considering the reactive power equivalent factor of electrical connections between grid nodes. This strategy determines the optimal reactive power output limit of SCs near the converter station to suppress DC commutation failures. Simulation results show that this strategy effectively utilizes the dynamic support capabilities of SCs, prevents DC commutation failures, improves HVDC transmission capacity, and enhances the safety and stability of the receiving end power grid, providing theoretical guidance for reactive power output control.

Controlling Output Power to Enhance the Investment Efficiency of Wind Farms by Maximizing the Capacity of Transmission Transformers and Integrating Energy Storage Systems

Controlling Output Power to Enhance the Investment Efficiency of Wind Farms by Maximizing the Capacity of Transmission Transformers and Integrating Energy Storage Systems

Robust hybrid control strategy for active power management in Kabertene wind farm within Algeria’s PIAT grid

The paper introduces a hybrid control strategy for optimised active power management in Algeria's Kabertene wind farm, crucial for the pole insalah-adrar-timimoune (PIAT) grid's stability. This strategy merges simultaneous interconnection and damping assignment (SIDA) passivity theory, passivity-based control (PBC), and multivariable proportional-integral-derivative (PID) controllers. This combined approach ensures frequency and voltage stability within the PIAT grid, which encompasses various elements like wind farms, solar plants, gas turbines, and dynamic impedance (Z), current (I), and active power (P) (D-ZIP), load model. By tailoring controllers for doubly fed induction generators (DFIGs) using SIDA-PBC principles and optimising internal parameters, the strategy achieves precise control of active power output. Additionally, particle swarm optimisation (PSO) refines power scheduling, which is especially beneficial for intermittent renewable sources like DFIGs. This comprehensive strategy offers numerous advantages: improved network stability, minimized voltage deviations, reduced frequency fluctuations, and enhanced integration of renewable energy sources. The paper emphasises practical implementation considerations, providing valuable guidance for efficient Kabertene wind farm operation and integration. This research contributes significantly to fostering cleaner and more reliable energy systems, facilitating the PIAT grid's transition towards sustainable energy generation.

Dynamic model of the functional parameter degradation changes in radio-electronic systems with two non-stationary random components corresponding to two types of noise

Problem statement. The processes of aging and degradation caused by the influence of environmental conditions, leading to changes in the functional parameters of radio-electronic systems, negatively affect the output characteristics and reduce the period of operation. The currently existing model of changes in radio-electronic system parameters, used for individual forecasting by extrapolation, includes only one random component representing various types of noise. At the same time, practical studies shows that the maximum amplitudes of different types of noise change at different rates. Therefore, for a more complete representation of the process of electromagnetic parameter changes over time, it is necessary to develop a model that takes into account this effect. The article discusses this problem using the example of the linear stabilizer output voltage. Goal. The main goal of the research presented in this article is to develop a model of functional parameter degradation that takes into account changes in maximum amplitudes of various types of noise in order to increase the accuracy of individual forecasting and the potential period of the device operation. Results. A generalized model of the electromagnetic parameter changes of the radio-electronic systems with two nonstationary random components characterizing various types of noise is presented. A software implementation of the presented model successfully verified on experimental data. Practical significance. The extended model of the functional parameter changes in radio-electronic systems can be used both in individual forecasting by extrapolation, and in the development of systems with a long period of operation, as well as devices intended for autonomous use. The prospects of using the presented model to simulate changes in functional parameters and determine the possibilities of compensating these changes are shown on the example of a frequency synthesizer with an automatic output power control system.

Simulation and experimental research on energy management control strategy for fuel cell heavy-duty truck

Energy Management Control Strategies (EMCS) play a significant role in improving the economy of Fuel Cell Heavy-duty Truck (FCHT). In this paper, a Single Fuzzy (S-Fuzzy) control strategy is introduced for the FCHT by considering the output characteristics of the fuel cell as well as the charging and discharging power characteristics of the power battery at the current state of charge (SOC). On this basis, the real-time difference between the current SOC and the target SOC of the power battery during the actual operation of the vehicle was further considered, the real-time correction coefficient of the fuel cell output power was introduced, and a Compound Fuzzy (C-Fuzzy) control strategy suitable for FCHT was developed. Meanwhile, the established vehicle model was verified dynamically and economically to ensure its accuracy, with the maximum speed error lower than 2%, the SOC error within 4.9%, and the relative dynamic simulation error of 1.3%. Utilizing co-simulation platforms Cruise and Matlab, the research demonstrates that the C-Fuzzy control strategy significantly outperforms the S-Fuzzy strategy, reducing Equivalent Hydrogen Consumption (EHC) by 1.63% under C-WTVC conditions and by 3.12% under CHTC-TT conditions. To counteract efficiency loss from fuel cell load fluctuations, a real-time EMCS based on C-Fuzzy control and multi-level power output was developed. Validated over a 122-km route, the real-time EMCS reduced the equivalent hydrogen consumption per 100 km of the FCHT to 10.14 kg, maintained the average fuel cell efficiency at 51.02%, and ensured stable SOC of the power battery within the predetermined target range.

Energy Harvesting and Storage with a High Voltage Organic Inorganic Photo‐Battery for Internet of Things Applications

Integrated local energy harvesting and storage is a critical prerequisite for energy autonomy of distributed sensing arrays required for the implementation of the internet of things (IoT). In this context, the monolithic integration of solar cells with metallic lithium‐based batteries into stacked high voltage photo‐batteries allows to provide said energy autonomy, with the smallest possible footprint and the highest resource efficiency. However current photo‐battery designs require additional electronics to control and match power output like maximum power point (MPP) tracking and overcharge protection. Herein a novel and compact monolithic photo‐battery design is provided, advantageously combining an organic solar cell with a NMC 622 versus metallic lithium‐based battery, matched in terms of VOC and cut‐off voltage, thereby achieving photo‐charging without any control electronics and energy release on demand at a very compact footprint of only 2.5 cm × 2.5 cm × 0.2 cm. Additionally, by applying a power profile simulating a temperature and humidity sensor over the course of a 24 h light and dark cycle, real world applicability of the photo‐battery in this type of applications is demonstrated.

Amplifiers in Multi–Band Scenarios—Output Power Requirements, Control and Performance Characteristics

Amplifiers in Multi–Band Scenarios—Output Power Requirements, Control and Performance Characteristics

Self-Measurement of the Admittance Matrix of AC–DC Power Converter by Internal Harmonic Injection

Frequency-domain impedance or admittance model is widely applied to analyze harmonic stability of power electronic converters. Conventionally, the converter impedance is modeled holistically, without exhibiting the sole effect of different control and phase-locked loop (PLL). Besides, harmonic voltage or current injection external to the converter is usually adopted, which involves dedicated equipment and introduces unexpected inner impedance. In this paper, the response of voltage perturbation upon AC-DC power converter along various voltage signal flow paths is analyzed, based on superposition principle. Each part of admittance and its effect on stability can therefore be quantified explicitly. By injecting harmonic perturbation through the identified paths within the converter controller, each part of admittances, with and without the concerned control or PLL blocks, are measured and summed to be the total admittance. Harmonic voltage mitigation control implemented on a grid-forming converter creates an ideal grid with constant voltage and nearly zero inner impedance at the injected harmonic frequency. The proposed admittance analysis and measurement is successfully applied to power converter with different PLL, voltage feedforward, output power control, DC voltage control and grid-forming cascaded control. Effectiveness of the analysis and the proposed admittance measurement approach are validated by comprehensive simulation and hardware test.

Voltage Control for a Loop Distribution System with Renewable Energy Sources

This paper describes and verifies a voltage control for a loop distribution system. The proposed method adopts SCADA system based on voltage data from IT switches, which are sectionalizing switches with sensor installed at 6.6kV distribution line. The proposed voltage control combines centralized control of a LRT and autonomous control of decentrally-allocated RESs. The tap change control of LRT takes the major role of the proposed voltage control. It is the extended type of LDC method which is generally adopted, and minimizes voltage deviations based on voltage data from each IT switch. The output power control of RES additionally and autonomously supports the voltage control when the voltage violation from the upper limit is unavoidable. The reactive power control in the vacant capacity of RES's inverter mainly works, and the active power control works when not enough. In order to check the validity of the method, the experimental simulations using an analog distribution system simulator are carried out. This study is supported by a specially-promoted research grant of Power Academy in 2009 from the Federation of Electric Power Companies of Japan.

Designing a High-Order Sliding Mode Controller for Photovoltaic- and Battery Energy Storage System-Based DC Microgrids with ANN-MPPT

This paper introduces a robust proportional integral derivative higher-order sliding mode controller (PID-HOSMC) based on a double power reaching law (DPRL) to enhance large-signal stability in DC microgrids. The microgrid integrates a solar photovoltaic (SPV) system, an energy storage system (ESS), and DC loads. Efficient DC-DC converters, including bidirectional and boost converters, are employed to maintain a constant voltage level despite the lower SPV output power. An artificial neural network (ANN) generates the optimal reference voltage for the SPV system. The dynamical model, which incorporates external disturbances, is initially developed and based on this model, and the PID-HOSMC is designed to control output power by generating switching gate pulses. Afterwards, Lyapunov stability theory is used to demonstrate the model’s closed-loop stability, and theoretical analysis indicates that the controller can converge tracking errors to zero within a finite time frame. Finally, a comparative numerical simulation result is presented, demonstrating that the proposed controller exhibits a 58% improvement in settling time and an 82% improvement in overshoot compared to the existing controller. Experimental validation using processor-in-the-loop (PIL) confirms the proposed controller’s performance on a real-time platform.

Research and Design of Fixed-Pitch Non-Grid-Connected Wind Power System

Traditional fixed-pitch wind turbine, whose rotational speed is a constant, adjusts its aerodynamic power according to the blade stall characteristic, and it has the advantage of being simple, robust and reliable, with simple and inexpensive electric systems. By introducing MPPT strategy on low wind condition and constant output power control on high wind condition, higher efficiency of fixed-pitch wind turbine can be obtained, which is realized by regulating the turbine rotational speed according to wind speed. In this paper, the variable speed regulation strategy is proposed, the stability characteristic based on the small signal model is analyzed, and the speed control technique based on disturbance observer and Internal Model PID controller is discussed in detail, some experimental results are presented, which show that the dynamic response of speed controller is favorable and efficiency of the plant is improved by tracking the maximum power point on low wind condition and keeping the turbine aerodynamic power at its rated value on high wind condition.

Multi-Agent Safe Graph Reinforcement Learning for PV Inverters-Based Real-Time Decentralized Volt/Var Control in Zoned Distribution Networks

To realize real-time voltage/var control (VVC) in active distribution networks (ADNs), this paper proposes a new multi-agent safe graph reinforcement learning method to optimize reactive power output from PV inverters. The network is divided into several zones, and a decentralized framework is proposed for coordinated control of reactive power output in each zone to regulate voltage profiles and minimize network energy loss. The VVC problem is formulated as a multi-agent decentralized partially observable constrained Markov decision process. Each zone has a central control agent that embeds graph convolution networks (GCNs) in the policy network to improve the decision-making capability. The GCN extracts graph-structured features from the ADN topology, reflecting the relationship between VVC and grid topology, and can filter noise and impute missing data. The training process includes primal-dual policy optimization to rigorously satisfy voltage safety constraints. Simulations on a 141-bus distribution system demonstrate that the proposed method can effectively minimize network energy loss and reduce voltage deviations, even in the presence of noisy or incomplete input measurements.

Optimization of load frequency control using grey wolf optimizer in micro hydro power plants

Micro hydro power plants (MHPP) is one of the renewable energy that can be utilized as a distributed generation with controllable power output. One common issue in MHPP systems is the non-constant rotation of the generator caused by load fluctuations. This instability leads to variable frequencies, which can potentially harm electrical equipment. To address this problem, the volume of water entering through the governor can be adjusted to synchronize the turbine and generator rotation with the load. This approach helps dampen frequency oscillations and ensures that the system operates within desired limits. Therefore, there is a need for technology that can enhance the performance of micro hydro power plant units, specifically load frequency control (LFC). This research proposes the application of the grey wolf optimizer (GWO) algorithm to optimize the PID controller parameters for MHPP LFC. MHPP has been modeled in both isolated and grid-connected modes using Simulink MATLAB R2020a. The best cost function value for an isolated mode system was obtained with ISEim, yielding a value of 0.067653, while for a grid-connected mode system, it was achieved with ISEgm, with a value of 0.015861. The results of the frequency deviation response performance of the LFC using GWO indicate that the fastest settling time was achieved with the cost function ITAEim in isolated mode, and with IAEgm in grid-connected mode. The cost function that produces the smallest peak overshoot and peak undershoot parameter values varied depending on changes in the system load.

Direct Torque Control for Series-Winding PMSM with Zero-Sequence Current Suppression Capability

The series-winding permanent-magnet synchronous motor (SW-PMSM) has the merits of high output power and excellent control performance, as does the open-winding permanent-magnet synchronous motor (OW-PMSM). Meanwhile, it can greatly reduce the number of power devices. However, due to the existence of the zero-sequence path, zero-sequence current occurs, which can cause additional losses and torque ripples. Thus, this paper proposes a novel direct torque-control strategy for the SW-PMSM with zero-sequence current suppression capability (ZSCS-DTC). First, the series-winding topology (SWT) and the voltage vector distribution in the SW-PMSM drives are analyzed. Secondly, the basic DTC (B-DTC) scheme for the SW-PMSM is investigated, and the defects of zero-sequence current open-loop control in the B-DTC scheme are revealed. Thirdly, a new voltage vector synthesis scheme is proposed for suppression of zero-sequence current while ensuring bus voltage utilization. A switching table is reconstructed with the newly synthesized voltage vectors. On this basis, a ZSCS-DTC scheme for the SW-PMSM is proposed based on zero-sequence current closed-loop control so that electromagnetic torque, stator flux linkage and zero-sequence current can be controlled simultaneously. Finally, the effectiveness of the proposed ZSCS-DTC scheme for the SW-PMSM drives is verified.

POWER PROCESSING AND CONTROL UNIT OF THE EECTRIC PROPULSION SYSTEM

Abstract. The report presents the results of the development of the PPU-500, which is part of the SPS-500 electric propulsion system based on the ST-40 Hall thruster. PPU-500 contains all power supplies necessary for the operation of the propulsion system: discharge; electromagnet; cathode heater and keeper; power supplies for valves and heaters of the storage and feeding working substance, as well as a standby power supply that ensures the standby mode of PPU operation.The converter of the discharge power supply is built using a bridge topology with a phase-shifted output power control circuit. The remaining power supplies are built according to the topology of a step-down synchronous converter with current or voltage stabilization. The discharge power supply is a controlled power supply. The power supplies for the cathode heater and electromagnet current sources are. The accuracy of power supplies output parameters in not worse than 1.5%. The valves of the feeding system are controlled in order to stabilize the pressure in the receiver by periodically turning on/turning off the high- and low-pressure valves. For control the valves, signals taken from pressure sensors installed in the receiver are used. The PPU control unit ensures an accuracy of maintaining pressure in the receiver no worse than 2.5%. The control unit of the PPU is built using a microcontroller with an ARM core. It implements the functions of monitoring the condition of the program, restoring the program firmware if an integrity violation is detected, and the ability to remotely flash a new version. To communicate the SPS-500 with the on-board control system, a galvanically isolated CAN interface is used. It can be also the RS485/RS42 interface.During operation of the propulsion system, operating parameters are measured using multi-channel ADCs and DACs. The obtained data, on the one hand, is used to assess the current state of the propulsion system and control Hall thruster operating modes. On the other hand, they are transmitted as telemetry signals reflecting the current state of the SPS-500, operating mode and emerging emergency conditions of the equipment. PPU is possible to alternately control two thrusters. Solid-state switches are used to switch the corresponding power sources.Testing of the PPU-500 as part of the SPS-500 propulsion system with the ST-40 Hall thruster and a flight prototype of the working substance feeding system confirmed the technical solutions adopted. The operating efficiency of PPU-500 for the nominal operating mode of the propulsion system is 94%.

Dual-band tunable microwave pulse signals generation based on a time domain mode locked optoelectronic oscillator

We propose and experimentally demonstrate a dual-band tunable microwave pulse signals generation method based on a time domain mode locked optoelectronic oscillator (TDML-OEO). The dual-band radio frequency (RF) combs are generated via injecting two single-tone signals and a low frequency signal. The two single-tone signals are injected to optimize the aimed center frequencies gain, while the low frequency signal is used to accomplish the multi-mode oscillation mode locking process. Furthermore, the dual-band RF combs with variable repetition rates of 3.69 MHz, 9.22 MHz, and 18.45 MHz are obtained with an over 72 dB ultra-high suppression of super mode noise as the TDML-OEO operates in the varied harmonic multiples mode locking state. Besides, by adjusting the amplitude and central frequency of the two injected local oscillator signals (LOs), a controllable output power and frequency tunability ranged from 11.1 GHz to 13.8 GHz are achieved for the generated dual-band RF combs. The proposed dual-band tunable microwave pulse generation method has great potential applications in multiband radars and electronic warfare.© 2023 Optica Publishing Group under the terms of the Optica Publishing Group Open Access Publishing Agreement.

Collective large-scale wind farm multivariate power output control based on hierarchical communication multi-agent proximal policy optimization

Wind power is becoming an increasingly vital source of renewable energy worldwide. However, controlling power generation in wind farms faces significant challenges due to the inherent complexity of these systems. To address this issue and maximize power output, we propose a novel communication-based multi-agent deep reinforcement learning approach for large-scale wind farm control. We introduce a multivariate power model for wind farms to analyze the impact of wake effects on power output. This model considers controllable variables such as axial induction factor, yaw angle, and tilt angle. To coordinate the continuous controls in large-scale wind farms, we propose the hierarchical communication multi-agent proximal policy optimization (HCMAPPO) algorithm. The wind farm is divided into multiple wind turbine aggregators (WTAs), and neighboring WTAs can exchange information through hierarchical communication to optimize power output. Our simulation results demonstrate that the multivariate HCMAPPO approach significantly increases wind farm power output compared to traditional PID control, coordinated model-based predictive control, and the multi-agent deep deterministic policy gradient algorithm. The HCMAPPO algorithm can be trained using a thirteen-turbine wind farm environment and effectively applied to large-scale wind farms. Importantly, as the wind farm scale increases, there is no significant increase in wind turbine blade fatigue damage from wake control. This multivariate HCMAPPO control strategy enables the collective maximization of power output in large-scale wind farms.

POWER SUPPLIES BASED FULL-BRIDGE LLC RESONANT CONVERTER PERFORMANCE FOR IH APPLICATIONS

This paper describes the analysis and performance of a full-bridge LLC resonant converter based on power supplies for IH applications. The analysis contains five components: half bridge inverter, resonant tank, high frequency transformer, rectifier and coil. The switching bridge generates a square waveform to excite the LLC resonant tank, which will produce a resonant sinusoidal current which is transferred to the secondary of the converter through a high-frequency transformer. As it scales the voltage up or down according to the output requirements. The load represented by the equivalent circuit of the coil and work-piece is fed by the current transformed by the rectifiers. Considering that load parameters and resonant frequency vary greatly in all phases of system operation, this paper provides improved knowledge of output power control for high temperature applications. The validity of the analyzed converter parameters had been simulated and tested using MATLAB-SIMULINK software. The results of testing demonstrated that the proposed scheme and assembly has good efficiency, and it is well suited for magnetic induction heating systems