WO2013120218A1

WO2013120218A1 - Adjusted single-phase electromagnetic induction reactor

Info

Publication number: WO2013120218A1
Application number: PCT/CL2012/000006
Authority: WO
Inventors: Luis VELOSO ARANCIBIA
Original assignee: Industrias Alterna Lgm Spa.
Priority date: 2012-02-13
Filing date: 2012-02-13
Publication date: 2013-08-22

Abstract

The invention relates to an adjusted single-phase electromagnetic induction reactor which has the aim of transforming to a very low impedance for the "triple" harmonics and which, by means of the connections and adjustment system thereof, is able to re-inject the zero sequence harmonic components along with the negative half-cycle component of the fundamental current and in turn recharge at any stage in the absence of a power supply, at the moment of connecting the phases to a specific electrical point or common neutral, but in "single-phase" form. In turn, and different from other three-phase alternatives, said single-phase nuclear induction reactor does not override the neutral current flow, diverting same to the transformer to compensate for the imbalance of the system, absorbing only the zero sequence harmonics and re-injecting said harmonics into the circuit, thus transforming it into a single-phase electromagnetic by-pass, which decreases the consumption of power from the network. In this manner, the difference in potential between neutral and ground of a contaminated circuit is also eliminated, especially from lighting or computing. As a result, the power factor also improves, because the "apparent" power (KVA) decreases from the standpoint of the network and the active power consumption of the charges is not changed, as a result of which the relationship between the former and the latter tends to equalize (1).

Description

TITLE: "RECTIFIED SINGLE-PHASE ELECTROMAGNETIC INDUCTION REACTOR"

SCOPE

The present invention relates to low-voltage electrical systems, more specifically to a rectified single-phase electromagnetic induction reactor, which absorbs residual currents thrown by solid-state lighting and electronics systems that propagate through neutral wires and systems. grounding of the electrical circuits, which aims to become a very low impedance for triplen harmonics and that through its connection - rectification and flow compensation system - is able to reinject the harmonic currents when connecting to the loads , reducing network consumption.

DESCRIPTION OF PRIOR ART

Electrical systems knew only three types of charges; Inductive, Capacitive and Resistive, which respond linearly to a sinusoidal excitation, with the particularity of advancing or delaying, by 90 °, depending on its capacitive or inductive condition, the current signal consumed by said loads and that for the In the case of resistive loads, they act only affecting the amplitude of the sinusoidal, without affecting its angular displacement!

With the incorporation of 1 Power Electronics to the electrical systems, a new behavior in the current was detected, and that is that it changed not only its angle of displacement, but also that its waveform was absolutely affected. This phenomenon is called "Harmonic Distortion."

A load is considered Nonlinear if its impedance changes along with the applied voltage, that is, as the amplitude of the voltage changes, the impedance of the load takes different values that are repeated periodically: These changes bring as a consequence, that the current is not sinusoidal, even if the applied voltage is.

These non-sinusoidal currents contain harmonic currents that interact with the rest of the electrical system, and generate distorted voltages that can affect the system busbars and the equipment connected to them.

With today's technology changes and the proliferation of the use of electronics, automatic control, digital systems, among others, problems with harmonic distortion have grown unexpectedly due to the types of non-linear loads that exist. These symptoms are not only seen in the industry, but everywhere, as well as commerce, clinics, malls and buildings.

One of the most common non-linear loads is the Power Sources (Switching Power Supply), Cycloconverters, Rectifiers, Controllers, Frequency Variators, Computers, Lighting Equipment with electronic ignition, etc., but for practical purposes the non-load loads Linear in two types: a) Zero Sequence Harmonic Generating Loads, are those that consume non-sinusoidal currents that generate harmonics that obey the following formula:

Harmonic number = (6n - 3), where n goes from i to infinity. That is, the following harmonics will be taken: 3, 9, 15, 21, 27, 33, 39, 45, ... b) Pulse harmonic generating loads, are those loads that work based on pulses, and that consume non-sinusoidal currents that generate harmonics that obey the following formula:

Harmonic No. = (k ^* n + 1), where n is the number of pulses of the load (it can be 6 pulses or 12 pulses) and k is a cycle constant that goes from 1 to infinity. That is, for a 6-pulse VDF, we will have the following harmonics: 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 35, 37, 41, 43, 47, 49, ... The manufacturers of frequency inverters of induction motors explain how these equipments improve the efficiency of the machines allowing to vary the operating speed according to the needs of the application, but warn that they produce harmonics of order 5, 7, 11 and 13.

Electronic ballasts are also presented as an important improvement, both for efficiency and for the life of the equipment. They only have the small problem of the increase in harmonic content.

Equipment such as arc furnaces, battery chargers, and UPSs are also producers of harmonics. But the biggest causes of problems are groups of small single-phase electronic loads, such as computers, printers, photocopiers, faxes, etc., connected between phase and neutral, usually in a 380/220 triangle-star system. In 1994 the percentage of non-linear loads was 15%, for 2010 it was estimated at 75%.

The problems generated by non-linear loads are related to the Power Factor, which is measured as the ratio between the Active Power "P" (Watts) over the Apparent Power "S" (VA) consumed by the system. This, traditionally for conventional loads, was matched to the ratio of voltage and current displacement (eos relación) due to the simplification of the power formula. But now, there is an energy that is used to supply the harmonic currents that the system demands. This new power is called "D" (VAd), where the ratio of the Power Factor is affected by component D.

Another problem generated by non-linear charges is related to systems by losses and currents by the neutral. Many electrical systems can accommodate certain low levels of Harmonic Distortion (THD), and because of that there are recommended levels for distortion of voltage (THD-V <5%) and current (THD-I <8%), these recommendations are suggested to be followed to avoid problems in your systems.

The most common problems are:

• Heating of the Transformers due to the circulation of harmonic currents through their windings.

• Circuit overload, which increases system losses.

• Decrease of the useful life of the Capacitors.

• Resonance in the system due to harmonic circulation.

• Vibration in the motors and wear on their bearings, · Loss of information in computer equipment.

• Erratic operations of control and protection equipment.

But without a doubt, the biggest problem generated by the Zero Sequence harmonics (and that is why they are named), is that they circulate through the neutrals of the systems, generating the problems that this means: noise, losses, heating, residual voltage, operation of protections, lifting of the potential of the neutrals with respect to earth, contrary torque in the motors and risk of accident or accident with the interaction of the personnel since these currents circulate through the grounding systems.

As with any problem, the best solution to avoid an effect is not to mitigate it, but to eliminate the cause that produces it. However, currently the most used systems to mitigate the effect of harmonics are passive filters, the most popular, built on capacitors and inductances adjusted to block or absorb certain harmonics. The applications in which they are used should be carefully studied to ensure compatibility with the rest of the system. They can become excessively bulky and create undesirable effects such as transients and resonances; Active filters, with sophisticated electronic systems begin to make their appearance in the market, but they are expensive, delicate and do not enjoy total acceptance. There are also applications with some types of transformer connection, such as triangle-star transformers, since "triple" (or Zero Sequence) currents add up to the neutral conductor, along with residual currents, but this creates the problem that in the primary, the "triples" of the unbalanced loads leave the conductors and those of the balanced loads are trapped in the windings of the triangle. Although this could be used to eliminate "triplen" balanced on the primary side, it is only valid in certain applications due to the problems generated by the recirculation by the triangle of these currents (considerable increase in transformer losses and equipment overheating). The transformers with secondary zigzag are formed by six equal windings, two per phase. This arrangement diverts the "triplen" from the neutral to the phase conductors; multi-output transformers, for example double output transformers are built with. two secondary windings offset by 30 degrees. The primary connected in a triangle blocks the triplen of balanced charges. The secondary ones compensate especially the harmonics of order 5, 7, 11 _; 19. Another possible configuration is quadruple output in which the windings are offset by 15 degrees. The primary as always blocks the "triplen" and the secondary those of order 5, 7, 11, 13, 17, 19, 29 and 31.

To maximize the attenuation of these harmonics, the non-linear loads connected at each output must be identical. Therefore, in these applications, the outputs of the different circuits are usually monitored. However, it is not recommended, for example, a double star transformer loaded with three output cabinets because the measurements do not reflect whether the secondary ones are balanced. . „,. _... „.

The invention patent document GB 1254425 dated 11/24/1971, by Denis Andrew Craddock, entitled "Improved Static Rectifier System", describes a static multi-phase rectifier transformer system, which seeks to minimize two disadvantages of conventional static rectifier systems, the first is the non-sinusoidal load current of the alternating current source, and the ripple voltage that appears in the DC output. The transformer comprises an axially symmetric electromagnetic system that has polyphase primary windings connected to an AC source, graduated and connected to a stator or an induction motor to produce a constant rotation of the magnetic field sinusoidally distributed in the space to cut the system. secondary windings of the transformer, comprising a plurality of equal windings connected in a ring formation and connected to the rectifiers to produce the direct current output and thus ensure that the power taken from each phase of the alternating current source is always proportional squared of the voltage of said phase.

Invention patent document US 6,043,569 dated 03/28/2000 by inventor Gregory NC Ferguson, entitled "Zero phase sequence current filter apparatus and method for connection to the load end of six or four-wire branch circuits" , describes a filter for Zero Sequence current, using the zig-zag method of the transformer windings. This does not guarantee adequate mitigation in unbalanced systems.

The patent document CL 47.154, dated April 13, 2007, of the inventor Luis Veloso, entitled "Device and transformer harmonic current mitigator for unbalanced electrical systems", shows a three-phase coil with double window core that absorbs the current and cancels the flows in three independent legs compensating the imbalance, but generating mutual induction with a considerable dispersion flow that achieves an efficiency of only 65% absorption, in turn generates a consumption in the positive half cycle that is equivalent to an inductive load connected to the net.

However, none of the documents of the prior art is a single-phase reactance, interconnected through "a" single leg that adds up all the flows generating a single resulting flow equal to "zero". In turn, this reactor is fed through a circuit of diodes that prevent the injection of positive half-cycle currents, eliminating the effect of inductive load from the network. With this monopolar effect, we achieve an absorption power close to 95% if we have dispersion flow and reduce the inductive load effect to 50%, achieving, unlike the others, "re-injecting the same harmonic current that we absorb from the load" resulting in a decrease in current consumption " rms "from the network. Unlike other similar three-phase applications, the flows are attenuated in the same equivalent reluctance that avoids dispersion losses, making the cancellation of the flows more efficient and the magnetization of the single-phase cores occurs with half the energy and the sequence currents zero.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows a diagram of the physical structure of the Coil of

Abduction or Protection of Residual Harmonics of the present invention.

Figure 2 shows an equivalent electromagnetic circuit of the union of the single-phase cores with the half-wave rectification system for the positive half-cycle. Figure 3 shows the circulation of the reinjected current during the absence of one of the phases. ^"

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

According to FIGS. 1 to 3, the invention of an electromagnetic induction reactor, which consists of a hybrid single-phase harmonic re-injection device of zero sequence harmonics for lighting systems, comprising: at least three monophasic silicoso steel cores oriented grain (1), armed with plates (2) to reduce losses due to stray currents; Aluminum or copper windings (3) isolated according to the current that will be injected and will circulate through said windings (3) made of multifilar wires to reduce losses in the coils (3), terminals (4) in ovens (5) suitable for each value of current, connection to a rectification system by means of diode devices (6) interconnected to each phase (7), (8) and (9) generating a half bridge rectifier with polarity opposite to the positive half cycle, to avoid the circulation of currents inductive in sense contrary to the magnetic flux of the zero sequence harmonics, in addition, these connection points are identified with the phases and the neutral of the system, the energy measuring device (10) that counts the current reinjected by said device and a metal tower type cabinet computational (not illustrated) with forced ventilation and lattice, suitable for the thermal flux to be evacuated and with an electronic measurement system using toroid current transformers (11) to measure and control the current reinjected into the system.

The protection of residual harmonics of the present invention, is basically a rectified single phase electromagnetic reactor (device of the invention), has the objective of transforming itself into a very low impedance for triplen harmonics, and which by means of its connection, rectification and compensation system flow, capable of re-injecting the harmonic currents when connected to the loads, reducing the network consumption. In turn, it is capable of supplying energy to the single-phase loads during the absence of one or two phases of the three-phase system, absorbing the energy from the present phase (s), channeling them through the single-phase core that feeds the loads without energy.

As Figure 3 shows, the electromagnetic equivalent circuit of each single-phase system is seen interacting together to absorb the currents and re-inject them through the rectified system.

The electromagnetic abduction of the phases occurs in a single central leg (12) of the nucleus (13) composed of three monophasic reluctances (14), (15), and (16) where the zero sequence flows (17) and (18) and each negative half cycle of the fundamental current signal is opposed in the same central leg (12) that allows the mutual induction of the phases to be canceled, generating a half-wave electromagnetic short circuit. This principle of mutual induction is based on the Faraday Law.

When making the multi-phase connection of each phase half-cycle through the three single-phase cores (13), (19) and (20), the current compensation of each phase (one of the other) will be independent, which will allow us compensate the current consumption in a phase that in case of failure ceases to receive direct energy from the source. This compensation will be done by increasing the energy consumption of the present phases (21) and (22) proportionally to the energy consumption of the absent phase (Figure 3).

To demonstrate the effects indicated, the following table is presented with the following tests carried out:

Table N ° 1: Non-linear three-phase system, 10 KVA, 380 Volts L-L, 220 Volts L-N.

THD: Harmonic Distortion

THD-I: Harmonic Distortion of the current.

^' Table No. 1 shows four different tests, two with balanced loads with and without the device of the invention connected, and two with unbalanced loads icon and without the device of the invention connected. The magnitude of the Neutral current can be appreciated when the PAR is connected, which increases its absorption capacity as the unbalanced phases This shows that the operation of the equipment is more efficient in more contaminated and unbalanced systems.

According to Figure 3, the equivalent circuit of a phase loss test is shown whose values are shown in Table 2:

Table N ° 2: Non-linear three-phase system, with absence of a phase in 380

Volts L-L, 220 Volts L-N.

THD: Harmonic Distortion

THD-I: Harmonic current distortion.

Table N ° 2 shows the values obtained in the tests similar to the previous case, but with the absence of the T phase. It is appreciated that the PAR absorbs the current difference and reinjects it to the absent phase, increasing the consumption of the phases present and only sends the current difference of the source to the source imbalance of the fundamental current signal, the zero sequence current remains in the equipment and the loads are fed back. '

Claims

1. - Rectified single-phase electromagnetic induction reactor, which absorbs residual currents thrown by solid-state lighting and electronics systems that propagate through neutral wires and grounding systems of electrical circuits, protection of residual harmonics zero-sequence single-phase rectified signal compensation, for use in unbalanced single-phase or multi-phase systems with non-linear loads, capable of reinjecting harmonic currents at the time of connecting to the loads, decreasing the network consumption and supplying power to the single-phase loads during the absence of one or two phases of the three-phase system, absorbing the energy from the present phase or phases, channeling them through the single-phase core that feeds the loads without energy, CHARACTERIZED because it comprises three single-phase cores of siloso-oriented grain-oriented steel; three windings of multifilar copper insulated according to the power or current flowing through said devados, with outputs to a half bridge rectifier that injects currents into the phases; in turn, the flows of said single-phase cores are contrasted in a single central leg, canceling the resulting flow to generate a minimum impedance, but not an exact counterposition, so as not to annihilate the zero sequence, but to reinject it through the phases , absorbing the neutral current and balancing the zero sequence harmonic components from the source to the load; it has terminals in terminals suitable for each current value; and a metal cabinet with forced ventilation and lattice, suitable for the thermal flow that you want to evacuate, provided with an electronic measurement system by means of toroid current transformers, to measure and control the current reinjected into the system.

2. - Rectified single phase electromagnetic induction reactor according to claim 1, CHARACTERIZED because the electromagnetic phase induction occurs in a single central leg of the core composed of three single phase reluctances, where zero sequence flows and each negative half cycle of the signal fundamental current are contrasted in the same central leg, which allows the mutual induction of the phases to cancel out, generating a half-wave electromagnetic short circuit.

3. - rectified single-phase electromagnetic induction reactor according to claims 1 and 2, CHARACTERIZED because the connected multi-threaded copper windings of each phase half cycle through the three single-phase cores, the current compensation of each phase will be independent ( one of the other), which will allow compensating the current consumption in a phase that in case of failure ceases to receive direct energy from the source; this compensation will be done by increasing the energy consumption of the phases present proportionally to the energy consumption of the absent phase.

4. - A rectified single-phase electromagnetic induction reactor according to claim 1, CHARACTERIZED in that it uses the negative half-cycle to magnetize the single-phase cores and operate in multi-phase systems independently; it absorbs harmonics of zero sequence and does not cancel them, but re-injects them to the respective loads; which allows to supply energy from the neutral when one of the phases is absent from the network, as well as allows its operation in a single-phase system.