Interharmonic Analysis Model of Photovoltaic Grid-connected System with Extended Dynamic Phasors

Sun

Int Trans Electr Energ Syst

et al. 2021

Current interharmonics caused by gird-connected PV systems have been noticed.From previous research, there is a trade-off between the interharmonic emission and tracking performance. In cyber-physical co-regulation systems, there also exists a trade-off between the cyber resource consumption and system performance. Motivated by this coincidence, a cyber-physical co-regulation based P&O MPPT algorithm is proposed for a three-phase single-stage grid-connected PV system to mitigate the interharmonic emission in this paper. In this algorithm, a cyber-physical model is built in which the sampling frequency is seen as the cyber state, and the step size is considered as the physical state. Based on the model, cyber and physical control laws are proposed in which the cyber and physical states are used to regulate each other. To apply the control laws, guidelines for designing control coefficients are also proposed based on the limits on the cyber and physical states to avoid chaotic behaviors caused by P&O MPPT characteristics. Compared with another mitigation algorithm without considering the cyber-physical characteristics, the proposed algorithm can reduce the peak

Section: Introductionsupporting

confidence: 81%

Mitigation of interharmonics in PV systems: A cyber‐physical co‐regulation based maximum power point tracking algorithm

Sun

Int Trans Electr Energ Syst

et al. 2021

“…Another reason for SaI occurrence is the work of renewable energy sources, such as photovoltaic plants [18,22] and wind power stations [3,7,12,20]. In the case of wind turbines, the presence of voltage fluctuations and subharmonics originates from such sources as tower resonance, blades passing in the front of the tower, small differences in the blades, wind turbulences, and rotor electrical or mechanical asymmetry [7,12].…”

Section: Origin Of Voltage Subharmonics and Interharmonicsmentioning

confidence: 99%

“…The presence of SaIs in a power system usually originates from the work of various power electronic appliances, renewable sources of energy, and loads of a fluctuating nature, including double-frequency conversion systems (inverters and high-voltage DC links), wind power stations, photovoltaic plants, arc furnaces, laser printers, AC motors driving piston compressors and other time-varying loads [2,[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. SaIs can also occur in an inverter output voltage because of voltage fluctuations in the DC link [6,13,23].…”

Section: Introductionmentioning

confidence: 99%

Line-Start Permanent Magnet Synchronous Motor Supplied with Voltage Containing Negative-Sequence Subharmonics

Gnaciński,

Pepliński,

Muc

et al. 2023

Energies

In some power systems, the voltage waveform contains frequency components less than fundamental, called subharmonics or subsynchronous interharmonics. Voltage subharmonics can be both positive- and negative-sequence, independent of their frequency (order). Subharmonics exert harmful effects on sundry electrical equipment, especially on rotating machinery; they cause various noxious phenomena, such as a local saturation of the magnetic circuit, increases in power losses and windings temperature, and torque pulsations leading to vibration of unacceptable severity. Notably, previous works reported excessive vibration of rotating machinery only under no-load, while under full load, rather moderate vibration occurred. This study deals with vibration analysis of a line-start permanent magnet synchronous motor (LSPMSM) supplied with the voltage containing negative-sentence subharmonics. Experimental investigations were conducted for a 3 kW, four-pole production LSPMSM for subharmonics of various values and frequencies. Voltage subharmonics of values significantly less than reported in real power systems were found to cause unacceptable vibration, especially under full load.

“…In this case, the distribution network power flow appears uncertain while multiple DGs are integrated into the distribution power network. At the same, they also may result in a variety of power quality problems, such as voltage deviation, frequency deviation, harmonics, and so on [11][12][13][14][15][16]. It is necessary to develop reasonable power quality estimation model for distribution network with DG, to reflect the power quality level of the network quantificationally.…”

Section: Introductionmentioning

confidence: 99%

A Novel Power Quality Comprehensive Estimation Model Based on Multi-Factor Variance Analysis for Distribution Network with DG

Ding

Liu

Chang³

et al. 2023

Processes

The power quality estimation for distribution network connected DG (distributed generation) is important in the power system. The significance testing for power quality indicator is less used in traditional power quality evaluation. However, the power quality indicator is affected by various factors of the power system, which seriously impact the power quality evaluation result. To solve this problem, A novel power quality comprehensive estimation model based on multi-factor variance analysis for distribution network with DG is proposed in this paper, in which the significance testing is carried out for power quality indicator with the various system factors, and then to generate the evaluation weights in different levels, further to obtain the power quality assessment results for single node. And then, the dual-significance tests are carried out to generate the weight of node and to obtain the comprehensive estimation result of whole system. At last, an example is developed to validate that, compared with the traditional power quality evaluation, the proposed method is more reasonable and effective in the power quality evaluation for DG connected distribution network.