WO2019047515A1

WO2019047515A1 - Balanced output circuit and method for three-phase electricity

Info

Publication number: WO2019047515A1
Application number: PCT/CN2018/081729
Authority: WO
Inventors: 罗太阁
Original assignee: 广东元森能源科技有限公司
Priority date: 2017-09-07
Filing date: 2018-04-03
Publication date: 2019-03-14
Also published as: CN107528333A

Abstract

A balanced output circuit and method for three-phase electricity. The balanced output circuit for three-phase electricity comprises: a control unit; a detection element for collecting a voltage signal and a current signal of three phases of electricity, i.e. A, B and C, output to a load; a capacitance assembly a connected between the phase A and the phase B; a capacitance assembly b connected between the phase B and the phase C; and a capacitance assembly c connected between the phase C and the phase A, wherein the capacitance assembly a, the capacitance assembly b and the capacitance assembly c all comprise at least one capacitor, each capacitor is serially connected to a switch, and the control unit is respectively electrically connected to the switch and a current transformer. By adjusting the capacitance between different phases, the currents of the three phases are balanced, so that the operating power factor of the three phases is improved.

Description

Three-phase electric balance output circuit and method

Technical field

The invention relates to the technical field of three-phase electric power, in particular to a three-phase electric balance output circuit and a method.

Background technique

In the ideal state of three-phase mains, the line voltage is 380V AC, the phase voltage is 220V AC, and the three-phase four-wire system is the most common three-phase transmission mode. Under ideal conditions, each phase load of three-phase electricity Approximate balance, so that the phase voltage of each phase is equal; but in the actual process, the three-phase load will generally be unbalanced, causing the imbalance of the three-phase electricity, and also causing current generation in the neutral line, reducing the three-phase electricity. The efficiency of use and the power factor, although there are many balance schemes in the prior art, all have shortcomings, such as complicated technical solutions.

Summary of the invention

The object of the present invention is to provide a three-phase electric balance output circuit and method for the deficiencies of the prior art, which can balance the output of the three-phase electric power and improve the electric power factor.

To achieve the above object, the present invention adopts the following technical solutions:

A three-phase electric balanced output circuit comprising:

control unit;

a detecting element for collecting voltage signals and current signals of three-phase electric power of A, B, and C output to the load;

Connected to the capacitor assembly a between the A phase and the B phase;

Connected to the capacitor assembly b between phase B and phase C;

a capacitor assembly c connected between phase C and phase A;

The capacitor component a, the capacitor component b, and the capacitor component c each include at least one capacitor;

Preferably, the capacitor component a, the capacitor component b, and the capacitor component c each include a plurality of capacitors connected in parallel;

Each capacitor has a switch connected in series; the control unit is electrically connected to the switch and the current transformer, respectively.

Further, the current of phase A is Ia, the current of phase B is Ib, the current of phase C is Ic, and Ia+Ib+Ic=3I, when Ia=I, Ib>I>Ic, the control unit according to Ib, The offset of Ic controls the number and capacity of capacitors connected in series between phase B and phase C, so that the corrected phase B and phase C currents are all I.

Further, the current of phase A is Ia, the current of phase B is Ib, the current of phase C is Ic, and Ia+Ib+Ic=3I, when Ia>I, and Ib>I>Ic, the control unit according to Ia , Ib, Ic offset, control the number and capacity of capacitors connected in series between phase B and phase C, and control the number and capacity of capacitors connected in series between phase A and phase C, so that the modified phase A, phase B, The C phase currents are all I.

Further, the current of phase A is Ia, the current of phase B is Ib, the current of phase C is Ic, and Ia+Ib+Ic=3I, when Ia>I, and I>Ib>Ic, the control unit according to Ia , Ib, Ic offset, control the number and capacity of capacitors connected in series between phase B and phase A, and control the number and capacity of capacitors connected in series between phase A and phase C, so that the modified phase A, phase B, The C phase currents are all I.

A three-phase electric balance output method comprises: a capacitor unit and a switch connected in series between any two phases, a control unit is connected to a control end of the switch, and the control unit detects a current signal and a voltage signal of each phase through the detecting unit; The control unit controls the corresponding switch to close according to the current or voltage offset of each phase, so that the current of the three phases is balanced.

When the two phase currents appear offset in different directions, the control unit controls the switch closure between the two phases, and the capacitor in series with the switch is turned on, so that the two phase currents are balanced.

When the three-phase currents are offset in different directions, the control unit controls the switch closure between the two phases with different offset directions, so that the currents of the three phases are balanced.

The technical solution achieves a beneficial effect: the current balance of the three phases is balanced by adjusting the capacitance of the connection between the different phases, so that the power factor of the three-phase operation is improved.

DRAWINGS

Figure 1 is a schematic view of the present embodiment.

Detailed ways

Embodiment 1: A three-phase electric balance output circuit, comprising:

control unit;

Connected to the capacitor assembly a between the A phase and the B phase;

Connected to the capacitor assembly b between phase B and phase C;

a capacitor assembly c connected between phase C and phase A;

The capacitor component a, the capacitor component b, and the capacitor component c each include a plurality of capacitors connected in parallel, and each capacitor has a switch connected in series; the control unit is electrically connected to the switch and the current transformer, respectively.

In the technical solution, the detecting component can be a transformer, and the current and voltage of each phase are collected by the transformer, and the control unit detects the current and voltage of each phase. When the three-phase current is unbalanced, the control unit controls the switch. A part of the capacitor assembly a, the capacitor assembly b, and the capacitor assembly c are in capacitive communication, and the unbalanced current is transferred, so that the phases are well compensated to achieve current balance. The control unit can be a PLC, a controller, etc.; the switch can be a relay or the like.

Further, the current of phase A is Ia, the current of phase B is Ib, the current of phase C is Ic, and Ia+Ib+Ic=3I, when Ia=I, Ib>I>Ic, the control unit according to Ib, The offset of Ic controls the number and capacity of capacitors connected in series between phase B and phase C, so that the corrected phase B and phase C currents are both I.

In the actual production process, the imbalance of the three-phase load may cause the current of the two phases of the load to be offset. For this case, the capacitor may be connected between the C phase and the B phase, and the excess energy of the B phase is on the capacitor. Storage, the energy of the capacitor is released on phase C; thereby balancing phase B and phase C. The A, B, and C phases here are only examples, and can be replaced in practical applications.

In the production process, the load of one phase may be larger, resulting in a larger current offset of the phase, and the other two phases are smaller. At this time, between phase A and phase C, phase B. A certain capacitance is connected in series with the C phase, and the active current is transferred through the capacitor to balance the three-phase current.

In the production process, the load of one phase may be small, resulting in a large current offset of the phase, and the other two phases are small. At this time, between phase A and phase C, phase B. A certain capacitance is connected in series with the A phase, and the active current is transferred through the capacitor to balance the three-phase current.

Embodiment 2: A three-phase electric balance output method includes: a capacitor unit and a switch connected in series between any two phases, a control unit is connected to a control end of the switch, and the control unit detects a current signal of each phase through the detecting unit The voltage signal is controlled by the control unit according to the current or voltage offset of each phase, so that the current of the three phases is balanced.

The capacitor unit can be a plurality of capacitors of different capacities, and the capacitor is connected in series with the corresponding switch between the two phases. The control unit controls the corresponding switch to close by detecting the current or voltage offset, thereby balancing the current of the three phases.

Offset in different directions means that one is offset in the positive direction and one is shifted in the negative direction, that is, one phase current is greater than the average value, and the other phase current is smaller than the average value.

The technical solution of Embodiment 1 can be applied to Embodiment 2.

The above content is only a preferred embodiment of the present invention, and those skilled in the art will have a change in the specific embodiment and application scope according to the idea of the present invention. The content of the present specification should not be construed as the present invention. limits.

Claims

A three-phase electric balance output circuit, comprising:

control unit;

a detecting element for collecting voltage signals and current signals of three-phase electric power of A, B, and C output to the load;

Connected to the capacitor assembly a between the A phase and the B phase;

Connected to the capacitor assembly b between phase B and phase C;

a capacitor assembly c connected between phase C and phase A;

The capacitor component a, the capacitor component b, and the capacitor component c each include at least one capacitor, and each capacitor has a switch connected in series; the control unit is electrically connected to the switch and the current transformer, respectively.
A three-phase electric balanced output circuit according to claim 1, wherein the current of the A phase is Ia, the current of the B phase is Ib, the current of the C phase is Ic, and Ia+Ib+Ic=3I, When Ia=I, Ib>I>Ic, the control unit controls the number and capacity of capacitors connected in series between phase B and phase C according to the offset of Ib and Ic, so that the corrected phase B and phase C currents are both I.
A three-phase electric balanced output circuit according to claim 1, wherein the current of the A phase is Ia, the current of the B phase is Ib, the current of the C phase is Ic, and Ia+Ib+Ic=3I, When Ia>I, and Ib>I>Ic, the control unit controls the number and capacity of capacitors connected in series between phase B and phase C according to the offset of Ia, Ib, and Ic, and controls between phase A and phase C. The number and capacity of the capacitors in series are such that the corrected phase A, phase B, and phase C currents are all I.
A three-phase electric balanced output circuit according to claim 1, wherein the current of the A phase is Ia, the current of the B phase is Ib, the current of the C phase is Ic, and Ia+Ib+Ic=3I, When Ia>I and I>Ib>Ic, the control unit controls the number and capacity of capacitors connected in series between phase B and phase A according to the offset of Ia, Ib, and Ic, and controls between phase A and phase C. The number and capacity of the capacitors in series are such that the corrected phase A, phase B, and phase C currents are all I.
A three-phase electric balance output method, comprising: a capacitor unit and a switch connected in series between any two phases, a control unit is connected to a control end of the switch, and the control unit detects a current signal of each phase through the detecting unit The voltage signal is controlled by the control unit according to the current or voltage offset of each phase, so that the current of the three phases is balanced.
The three-phase electric balance output method according to claim 5, wherein when the two phase currents are offset in different directions, the control unit controls the switch between the two phases to close, and the capacitor in series with the switch Conducted to balance the two phase currents.
A three-phase electric balance output method according to claim 5, wherein when the three-phase currents are offset in different directions, the control unit controls the switch closure between the two phases having different offset directions, so that Three-phase current balance.