What does the power factor suggest? Why must it be remedied?

Today’s industrial, industrial, retail, and residence settings utilize a boosting variety of electronic devices such as personal computers, monitors, web servers, and copiers, which are commonly powered by switching over power materials (SMPS). Otherwise, properly developed, nonlinear loads can be produced that may enforce the harmonic currents or voltages that show up on the primary grid. Harmonics can damage the cable televisions and tools in this network as well as various other equipment attached to it. Possible problems include overheating and fire dangers, high voltages, distributing currents, equipment failures, element failings, and other potential consequences. If a nonlinear lot has a missing power element, it can rapidly produce these harmonics. Various other loads may show poor power aspects without generating harmonics. This paper concentrates on the above problems, the scenarios that lead to destructive harmonics, and sensible ways to reduce that harmonic.

Both leading reasons for poor power factor

We can state that the power factor of an electrical gadget or electronic gadget is the proportion of the power it acquires from the keys and the energy it takes in. An “ideal” device would have a power factor of 1.0 and would undoubtedly ruin all the power it gets. It would undoubtedly look like resisting direct tons: a ton that continues to be constant regardless of the input voltage, without considerable inductance or capacitance. Number 1 reveals the input waveform that would appear in such a gadget. Initially, the existing waveform is in the same stage as the voltage, and also 2nd, both waveforms are sinusoidal.

Number 1: Input voltage as well as present waveforms for a device with PF = 1.0

In practice, some gadgets do have a regular power aspect, yet some do not. There are two reasons for the inadequate power aspect of equipment: either the current it draws run out stage with the supply voltage, or the waveform used to illustrate the current is non-sinusoidal. The out-of-phase situation referred to as the “variation” power factor is usually related to motors inside commercial devices. On the other hand, the non-sinusoidal issue referred to as the “distortion” power factor is generally associated with desktop computers, photocopiers, and battery chargers driven by switching power supplies (SMPS). Digital gadgets such as desktop computers, photocopiers, and battery chargers are triggered by switching over power products (SMPS). Allow’s quickly take a look at the changed power aspect and then talk about the distortion instance, which is a lot more pressing for electronic power system developers to comprehend. Nonetheless, it is vital to understand both factors. As an example, some engineering programs discuss power aspect problems just in motors, and students are perplexed when they later come across the even more deficient power variables exhibited by SMPS.

Electric Motor as well as Displacement Power Factor Problems

Motors produce a strong electromagnetic field, producing a voltage or inverse electrical perspective contrary to the voltage utilized. This can create the supply present to drag the voltage made. The resulting opposite-phase existing component does not offer a usable power source, but it increases the facility’s power supply capability and power costs. Mounting capacitors between electric motors reduce stage lag and also boost their power aspect.

SMPS as well as Distortion Power Aspect Problems

Variation power factor lots do not cause harmonics and their associated troubles, yet distortion power aspect tons such as SMPS can cause these troubles unless their power element is boosted.

The Air Conditioning front of an SMPS usually consists of a bridge rectifier adhered to by a big filter capacitor. The circuit utilizes the present from the AC key circuit only when the line voltage goes beyond the voltage of the capacitor. This results in a regular Air Conditioner circulation, creating a non-sinusoidal pattern, as shown in Figure 2.

Figure 2 reveals the non-sinusoidal present waveform.

Number 2: Non-sinusoidal present waveform because of SMPS with wrong power factor

The waveform can be analyzed using the Fourier change (a mathematical procedure) and disintegrated into a collection of sinusoidal components, including the fundamental frequency (50Hz in Europe and 60Hz in the United States) and several odd multiples the absolute regularity, known as harmonics. The 3rd harmonic is 150Hz (or 180Hz), the fifth harmonic is 250Hz (300Hz). Number 3 reveals the regular harmonic spectrum of a digital SMPS load. The essential element is adequately taken in by the SMPS, while the harmonics are responsive and present the issues explained above. The proportion of the total amplitude to all harmonic amplitudes gives the device’s power variable.

Figure 3: Normal International Criterion for Harmonic Spectrum of Electronic SMPS Plenties

There is a global standard that explains and establishes appropriate restrictions for the generation of the primary harmonics of a product. Within the EU, the recommendation requirement is IEC61000-3-2, covering tool power levels from 75W to 600W. The common categorizes gadgets into four classifications: A, B, C, and D. Category D consists of computers, desktop computer screens, and TV receivers.

Proven PFC Solutions as well as Ingenious PFC Solutions

While there are easy power variable remedies, the general industry view is that functional designs supply the best power factor enhancement. These are generally based upon boost converter modern technology, as displayed in Number 4.

Number 4: Energetic Power Element Adjustment Circuit with Increase Technology

Figure 5: Voltage and present waveforms of an energetic increase circuit

For this purpose, the control circuit uses the input voltage waveform as a template. The control circuit determines the input present, contrasts it to the input voltage waveform, and readjusts the boost voltage to create a present input waveform of the same shape (5-I). At the same time, the control circuit keeps an eye on the bus voltage and adjusts the boost voltage to maintain an approximately controlled DC result (5-B). The main feature of the control circuit is to offer sinusoidal input present, so it permits the DC bus voltage to differ somewhat.

Using an energetic power element improvement circuit results in few discontinuities in the input current, so the distortion and harmonic content of the input current drawn from the line is reduced. Nevertheless, Vicor has just recently introduced a modular AC front-end based on its newest dynamic converter design, called the Adaptive Unit.

This AC front-end brings several boosted functions to system designers. Specifically, it provides a universal input from 85V to 264VAC, high efficiency, and also high power thickness, with particular consideration provided to be a complete solution that consists of a separated, controlled DC outcome as well as rectification and also power aspect improvement. The gadget minimizes A/C line harmonic breeding, boosting general power high quality at the system and facility level. The complete harmonic distortion is far better than EN61000-2-3 requirements, while the high changing frequency and resonant conversion streamline the external filtering system and satisfy EMI basic specs.


Ena Leung

Ena Leung


您的电子邮箱地址不会被公开。 必填项已用*标注

3 × 1 =

en English

The Newest & Hottest Products In 2022

All your answers are in SANPU’s monthly report, 2022

We picked up the most popular items from 1,000+ items of our clients, to help you find the wining product.

Ask For A Quick Quote

We will contact you within 1 working day, please pay attention to the email with the suffix “@smpspower.com”.