The Switching Function: analysis of power electronic circuits

Marouchos, C. C.

doi:10.1049/pbcs017e

Cited by 38 publications

(41 citation statements)

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“…6 References Owing to the non-linearities of diode rectifier, the current and voltage switching functions are applied to derive the relationship between the input voltages and input currents at the input terminal of the diode rectifier [20]. Therefore the relationship between them at the fundamental frequency can also be expressed in the form of admittance at the corresponding frequency, as noted as [Y l3 ].…”

Section: Comparison Resultsmentioning

confidence: 99%

Mathematical analysis of the equivalent impedance at the harmonic frequency for the proposed aircraft power system

Zhou

Sumner

Thomas

2013

IET Electrical Systems in Transportation

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(2013) Mathematical analysis of the equivalent impedance at the harmonic frequency for the proposed aircraft power system. IET Electrical Systems in Transportation, 3 (4). 87 -101. ISSN 2042-9738 Access from the University of Nottingham repository: http://eprints.nottingham.ac.uk/2469/1/Zhouaircraft.pdf Copyright and reuse:The Nottingham ePrints service makes this work by researchers of the University of Nottingham available open access under the following conditions. This article is made available under the Creative Commons Attribution licence and may be reused according to the conditions of the licence. For more details see: http://creativecommons.org/licenses/by/2.5/ A note on versions:The version presented here may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the repository url above for details on accessing the published version and note that access may require a subscription.For more information, please contact eprints@nottingham.ac.uk Abstract: The proposals for the 'More Electric Aircraft' place a significant, increased demand on the electrical power distribution system. To increase safety and reduce aircraft maintenance times on the ground, there is a greater need to quickly identify and locate electrical faults within the electrical distribution system. The work presented in this study provides the mathematical basis for the use of power system harmonic impedance measurement for identifying and locating faults within power cables. The method is passive -that is, it does not require the injection of any test signals -and can potentially be embedded into a centralised equipment controller to provide intelligent, real time diagnostics. The method monitors the harmonic line-line self-impedance at strategic points in the distribution system; this is obtained by measuring load voltage and current. Faults can be identified and located within a few fundamental cycles, and therefore provides a 'backup protection' system which does not require measurement of the line current. It also can provide details of the fault location and could therefore be a significant aid to aircraft maintenance. This study derives the theoretical basis of the scheme and provides simulation results for a proposed aircraft power system to demonstrate the validity of this approach to detect and locate faults within the system.

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Section: Comparison Resultsmentioning

confidence: 99%

Mathematical analysis of the equivalent impedance at the harmonic frequency for the proposed aircraft power system

Zhou

Sumner

Thomas

2013

IET Electrical Systems in Transportation

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“…The switching function F r (t) in (3) is a pulse function and can be expressed by the sum of sinusoids, according to the Fourier series, as [11]:…”

Section: General Model For Reactive-power Compensator Circuitmentioning

confidence: 99%

“…The switching function F r (t) should be chosen so that V sw (t) (the voltage across the switched part of the circuit) has very few or no harmonics. This can be achieved if F r (t) occurs at high frequency [11]. For a switching frequency 'm' times the fundamental frequency (50 Hz or 60 Hz), the lowest harmonics in the line current (above the fundamental) are of order 'm71'.…”

Section: Fig 1 General Model Of Proposed Var Circuit and Its Switchimentioning

confidence: 99%

“…3 Ideal phasor relationships between V in (t), V L (t), V sw (t), and i(t) in general model of proposed VAR circuit y ¼ 01 [11]. For the purpose of this analysis and for all practical purposes the ripple current is limited to the first two harmonics; they are cosine terms with no phase delay.…”

Section: Fig 1 General Model Of Proposed Var Circuit and Its Switchimentioning

confidence: 99%

“…The main role of the capacitor in this case is to attenuate only the high-frequency (2.5 kHz) harmonic voltages across its terminals but not the fundamental (50 Hz). In the case of inverter circuits [11], the action of the switches is to allow a strong low-frequency (100 Hz) current through the DC-link capacitor. The main role of the capacitor in this case is to attenuate any harmonic voltage ripple across its terminals down to the order of the 50 Hz fundamental frequency.…”

Section: Introductionmentioning

confidence: 99%

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Variable VAR compensator circuits

Marouchos

Darwish

El-Habrouk

2006

IEE Proc., Electr. Power Appl.

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A family of two reactive-power compensator circuit is presented. A general model of some basic linear elements and switching function blocks is developed first. Then the two proposed compensator circuits are derived from the generalised model. The proposed circuits are capable of supplying leading as well as lagging reactive currents in stepless variation without using an inverter configuration. The switching frequency is in the range of 2.5 kHz and the largest capacitor utilised does not exceed 60 mF. The generated reactive current, in either the leading or lagging modes, contains less than 2% total harmonic distortion.

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Power enhancement of single‐phase transformer‐less grid‐connected cascaded half‐bridge diode clamped inverter under partial shaded photovoltaic

Rao

Saini

2021

Int Trans Electr Energ Syst

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This study presents a power-enhanced cascaded half-bridge (HB) diode clamped transformer-less multilevel inverter for grid-connected large-scale photovoltaic (PV) system addressing the problem of unequal power in isolated diode clamped (DC)-link due to partial shading. The HB diode clamped has the feasibility of increasing double times the DC-link voltage compared with the conventional cascaded h-bridge to enhance the inverter's power rating without compromising the count and peak inverse voltage of switching devices. Under partial shading conditions, the DC-link of individual HB suffers from different voltages and leads to unbalanced capacitor voltages. The proposed control scheme stabilizes the DC-link voltage of individual HB, extracts maximum active power from PV, and injects the same into the grid. The injected grid current total harmonic distortion satisfies the IEC 61727 and IEEE 1547 standards. PV parasitic capacitance in the transformer-less gridconnected system leads to leakage current. In the present work, LC-filters are placed among the power cells to bring these currents below 30 mA as per German standards VDE V 0126-1-1. For the planned inverter, a mathematical model using the switching function theory has been derived. The inverter's performance has been tested under partial shading conditions by using the MatLab/Simulink platform and experimentally verified with the software-inthe-loop real-time digital simulator OPAL-RT 5700. List of symbols and abbreviations: C a1 = C a2 = C a3 = C a , Filter capacitor; L a1 = La2 = L a3 = L a , Filter inductor; c, Number of HB's; n, Number of voltage levels; V dc , DC-link voltage of a capacitor; I dc , DC-link current of a HB; V HBc , AC output voltage of a HB; f x , Switching function; V x , Phase voltage; l, 1 (upper capacitor), 2 (lower capacitor); R s , Series resistance in PV cell; R sh , Parallel resistance in PV cell; I p , PV cell current; V p , PV cell voltage; I 0 , Saturation current; I 0r , Reverse saturation current; I sh , Shunt resistor current; I sc , Short circuit current; I ph , Photo current; λ, Solar irradiance; q, electron charge; k, Boltzmanns constant; T, Temperature; k i , Short circuit thermal coefficient; T 0 , Reference temperature; E, Bandgap energy; a, Number of parallel PV modules; b, Number of series PV modules; P mpp , Rated peak power; V oc , Open-circuit voltage; I sc , Short circuit current; V mpp , Rated voltage; I mpp , Rated current; δ, Duty cycle; T on , On time; T t , Switching period; i a , Grid current; v a , Grid current; L a , Filter inductance; R, Filter resistance; T s , Sampling time; m c *, Modulating signal; V cm , Commom-mode voltage; V tcm , Total common mode voltage; V dm , Differential-mode voltage; i cm , Common-mode current; C PV ,

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The Switching Function: analysis of power electronic circuits

Cited by 38 publications

References 0 publications

Mathematical analysis of the equivalent impedance at the harmonic frequency for the proposed aircraft power system

Mathematical analysis of the equivalent impedance at the harmonic frequency for the proposed aircraft power system

Variable VAR compensator circuits

Power enhancement of single‐phase transformer‐less grid‐connected cascaded half‐bridge diode clamped inverter under partial shaded photovoltaic

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