Dynamic Harmonic Distortion Analysis and Mitigation ...

Harmonic distortions in DC third rail systems can cause overheating of electric motors and transformers. Single-tuned filters and shunt active harmonic filters (SAHFs) are often used to mitigate the harmonic distortions. However, there is a lack of studies on the effects of train dynamics on harmonic distortions. This paper aims to investigate the influence of …

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Principles for Controlling Harmonics

Not only does this shunt a troublesome harmonic current off the system, but it completely changes the system response, most often, but not always, for the better. Add a reactor to detune the system . Harmful resonances generally occur between the system inductance and shunt power factor correction capacitors.

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Analysis and Design of Third-Harmonic Current Injection Active …

Third-harmonic current injection (3rd-HCI) active filter circuit could be utilized to eliminate low-frequency harmonics generated by the three-phase uncontrolled rectifier. However, some problems exist when the circuit operates in the 115 Vrms/400 Hz aircraft power system. The inductor in the 3rd-HCI active filter circuit is not strictly volt-second balance in one switching …

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Understanding Power System Harmonics

and as shunt capacitors are employed in greater numbers to improve power factor closer to unity. ... (e.g. 120Hz), third harmonic (e.g. 180Hz), and so on. The individual harmonics add to reproduce the original waveform. The highest harmonic of ... and half-wave symmetric waveforms have no even-ordered harmonics. The current drawn by electronic ...

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Modified Modular Multilevel Converter With Third-Order Harmonic …

In [19], the third-order harmonic voltage and second-order harmonic current are injected in the MMC to reduce capacitor voltage ripples. In this method, the injection of the common-mode voltage is ...

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Capacitor voltage feedforward decoupling control based on third ...

The proposed algorithm injects the third harmonic into the modulation waves of SPWM, which makes the maximum linear modulation index of SPWM the same as that of SVPWM, to reduce the capacitor voltage fluctuations and current harmonics. The calculation of the third harmonic only requires a standard sorting algorithm and a simple linear operation ...

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IMPLEMENTATION OF THIRD HARMONICS INJECTION …

the tracking performance of the third-harmonic current. To solve these problems, this paper studies the two-stage matrix converter with third harmonics injection and demonstrates that …

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3rd Harmonic Blocking Filter: Is the Cure Worse Than …

The 3rd harmonic blocking filter is a parallel inductive/capactive (L-C) network tuned to the 3rd harmonic (180 Hz for a …

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3rd Harmonic Blocking Filter: Is the Cure Worse Than the Disease?

Triplen current harmonics (mainly 3rd and 9th) sum arithmetically in the neutral and circulate in the primary windings of transformers. ... During each voltage half cycle, the smoothing capacitor is charged by the voltage peak. Another way to conceptualize harmonic distortion is to consider the current and voltage waveforms themselves. A ...

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Third Harmonic Injection Circuit to Eliminate Electrolytic …

When a third harmonic current is injected to the input current of the LED driver, the required capacitance of the driver can be reduced. The proposed circuit can control an injection ratio and has simple circuitry. The synchronous third harmonic is generated by a phase locked loop (PLL), a 1/3 counter, and op-amps

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Third Harmonic Injection Circuit to Eliminate Electrolytic …

Abstract – A new third harmonic injection circuit for light-emitting diode (LED) drivers is proposed to eliminate electrolytic capacitors and thereby extend the lifetime of LED drivers. When a …

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Design and application of a single‐tuned passive harmonic filter to ...

Besides, the unbalance-current protection of a capacitor bank is introduced in this paper. Finally, the proposed filter is implemented in an actual traction substation, from the field measurement results; the proposed harmonic filter delivers very good performance. ... The 3rd and 5th harmonic current contents meet the emission limit with the ...

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The 3rd harmonic filter configuration | Download Scientific Diagram

Harmonic filters have the capability to contribute a substantial amount of reactive power for the purpose of power factor improvement [11]. By installing Qcom (kVAR) in an active power (kW), it ...

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Generator Third-Harmonic Protection Explained

1. Third-harmonic schemes use the third harmonic produced by most machines. Exceptions include units with a two-thirds short-pitch ratio that notch the third harmonic. a) If the terminal PT is wye-grounded, a third-harmonic measurement at the terminal (VT3) is available. In this case, both VT3 and the neutral third harmonic (VN3) measured across a

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The 3rd harmonic filter configuration | Download …

Harmonic filters have the capability to contribute a substantial amount of reactive power for the purpose of power factor improvement [11]. By installing Qcom (kVAR) in an active power (kW), it ...

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Understanding Total Harmonic Distortion (THD) in Power Systems

Voltage and current waveforms for a linear power supply. Because of the obvious distortion in the current, you would expect the harmonic current content to be high, and this can be seen in the FFT of the current in Figure 7: Figure 7. Harmonics of current flowing into a linear power supply . Clearly there is a lot of distortion in the current.

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Harmonic analysis of DC capacitor current in sinusoidal and …

The voltage ripple and power loss in the DC-capacitor of a voltage source inverter depend on the harmonic currents flowing through the capacitor. This paper presents a double Fourier series based analysis of the harmonic contents of the DC capacitor current in a three-level neutral-point clamped (NPC) inverter, modulated with sine-triangle pulse-width …

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Influence of third harmonic injection on modular multilevel …

the SMs and reduce SM capacitor voltage ripple, but at the expense of higher semiconductor current stresses. Third harmonic injection is another attractive approach for MMC control, due to the high DC voltage utilisation ratio. In [10], the MMC was first proposed for high voltage application and triplen

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(PDF) Enhancing Inductive Operation of Low-Capacitance …

The proposed solution is based on the injection of an optimal third harmonic circulating current to suitably shape the capacitor voltages aiming at avoiding overmodulation.

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Second-and third-harmonic distortion of a MOSFET gate capacitor …

Download scientific diagram | Second-and third-harmonic distortion of a MOSFET gate capacitor excited by a sinusoidal current component: calculated second-harmonic distortion using (3): calculated ...

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Harmonic Filter Circuit: How to remove Harmonics using Active …

Harmonic is a voltage or current occurs at a multiple of the fundamental frequency. It is often regarded as noise in the power line. The harmonics in the power system can be classified into two types: current harmonics and voltage harmonics. The current harmonics induced by the non-linear load such as VSDs (variable speed drives). The …

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Presentation On Harmonic Filter Design

capacitor current limiting fuses p aux capacitor connected wye-ungrounded pt (3) ct rollout breaker capacitor current limiting fuses p harmonic filter reactors connected wye-ungrounded ct rollout breaker high-pass resistor ct capacitor current limiting fuses p high-pass resistor connected wye-ungrounded ct ct rollout breaker capacitor current ...

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How to manage harmonic currents affecting the neutral

Otherwise, the third harmonic currents in the three phases are not equal and the ampere-turns on a single core at the secondary cannot be compensated in full. A third order harmonic current can therefore circulate in the primary winding, and therefore in the power supply line. Go back to Measures ↑. 4. Reactance with zigzag connection

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An Introduction to Harmonics

A harmonic is a current or voltage component at a frequency that is an integer (whole number) multiple (2nd, 3rd, 4th, etc.) of the fundamental frequency. For example, when the power supply is 60 Hz AC, the first …

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Harmonics 101

As you can see in this figure, the 3rd harmonics between the phases add together, which creates oscillating current. ... and capacitance. It creates a low-impedance path for harmonic currents at the natural frequency. This results in high harmonic currents through the capacitors. Series resonance can result in a high-voltage distortion level ...

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Harmonics in AC Power Systems

Harmonics are classed according to their order, which is a multiple of the fundamental frequency. For example, if the fundamental frequency is 50 Hz, the second harmonic is 100 Hz, and the third harmonic is 150 Hz. Even-order harmonics (2 nd, 4 th, 6 th, etc.) and odd-order harmonics (3 rd, 5 th, 7 th, etc.) have distinct impacts on power ...

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Interaction of Harmonics with Capacitors | Request PDF

The mains current in an AC/DC converter contains periodic current pulses, due to the action of the rectifier and the output buffer capacitor. The high current peaks cause harmonic distortion of ...

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HARMONICS

When the input voltage value is higher than voltage on the capacitor, the diode will conduct current through it. This results in a current waveform as shown in Figure 5, and harmonic spectrum in Figure 6. ... As previously mentioned, the third harmonic current from each phase in a four-wire wye or star system will be additive in the neutral ...

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Performance analysis and capacitor design of three‐phase …

The design capacitor with 1.7 mF can suppress input third harmonic current and achieve smaller voltage droop at the same time. 8 Conclusion In this paper, an accurate model of three-phase uncontrolled rectifier is proposed to describe circuit characteristics under slightly unbalanced voltage conditions.

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Third-order current harmonic suppression and neutral-point …

The imbalance of capacitor voltage on the DC side of the inverter will cause the third-order current harmonics and the device will be damaged greatly with the increase of voltage stress.

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