CN103956910B - A kind of three-phase of series connection indirectly matrix form medium-high voltage frequency converter - Google Patents

Abstract

The invention discloses a kind of three-phase of series connection indirectly matrix form medium-high voltage frequency converter, step-down transformer T1 has n secondary, and auxiliary winding phase place is identical, without phase difference; Three-phase---three-phase matrix array A1-An forms the capable array of 1 row n by n three-phase-three-phase matrix converter unit, in array, every a line is corresponding with the often group secondary of step-down transformer connects, the every of each three-phase---three phase matrixs exports all through isolating transformer connected in series together mutually, thus forming AC three-phase output, the work of regulating and controlling whole system is responsible for by controller.The present invention can by the low power three-phase of low pressure---three-phase that three-phase matrix converter or high pressure IGBT form---three-phase matrix converter obtains the high voltage source of amplitude, frequency-adjustable through isolating transformer connected in series, realize output voltage and input current is sine wave, input power factor is close to 1, and energy capable of bidirectional flowing, possess the advantages such as four quadrant running ability, be applicable to middle high-pressure driving by A.C.motor field.

Description

A kind of three-phase of series connection indirectly matrix form medium-high voltage frequency converter

Technical field

The present invention relates to a kind of frequency converter, particularly relate to a kind of three-phase of series connection indirectly matrix form medium-high voltage frequency converter, belong to power electronic equipment technical field.

Background technology

Mesohigh large power alternating-current electric power transmission field, the converters scheme applied at present mainly comprises: 1, power switch or the power cell friendship orthogonal high voltage converter of directly connecting; 2, the three-level AC orthogonal inverter of diode clamp and electric capacity fly across many level AC and DC hybrid transmission system; 3, two level current mode AC and DC hybrid transmission system.But in actual applications, this three classes medium-high voltage frequency converter all inevitably existing defects: 1 class frequency converter exists power device One's name is legion, equipment is huge, energy in bidirectional flow is difficult; 2 class frequency converters exist that harmonic wave is large, power factor is low, inefficiency; 3 class frequency converter du/dt impacts are large, humorous involves idle impact greatly, on electrical machine insulation impact greatly.Based on above situation, a kind of novel mesohigh converters is needed to occur, its indispensable following characteristics: without the need to the use of electrochemical capacitor or self-healing electric capacity; Four quadrant running ability can be realized between electrical network and converter; The capacity of single inverter unit comprises voltage endurance capability and current capacity can be applicable to current main flow requirement on devices.Such frequency converter not only output voltage amplitude can regulate, and input current presents sine wave, and power factor is close to 1, and the step-down transformer vice-side winding structure of its high voltage supply is simple, can design identical.Therefore, whole system cost is low, the life-span is long, reliability is high, function admirable, is applicable to the developing direction of following mesohigh electronic frequency convertor.The medium-high voltage frequency converter that can meet above condition is the cascaded multiple AC-AC frequency converter of high pressure---low pressure---high-voltage type, and series connection three-phase matrix form medium-high voltage frequency converter is exactly wherein a kind of indirectly, at present, not yet has correlation technique openly to report.

Summary of the invention

The object of the invention is to for the deficiencies in the prior art, propose a kind of three-phase of series connection indirectly matrix form medium-high voltage frequency converter, it has four quadrant running ability, output AC voltage and frequency continuously adjustabe, input current and output voltage are sinusoidal wave, and input power factor is 1 substantially, harmonic effects is negligible, its structure is simple, and maintenance cost is low, system highly versatile, reliability are high, performance good, energy-conservation, has broad application prospects.

Solution of the present invention solves existing technical problem by the following technical solutions.

A kind of three-phase of series connection indirectly matrix form medium-high voltage frequency converter, comprising: inlet wire filter LC, step-down transformer T1, three-phase---three-phase inverter array A1-An, series connection isolating transformer T1-T3 and master controller.

Described inlet wire filter LC is made up of three inductance L 1-L3 and three filter capacitor C1-C3, three filter inductances are serially connected in three-phase incoming line respectively, its input is connected with electrical network, output is connected with the input of step-down transformer, one end of three filter capacitors is connected respectively to the output of three filter inductances, the other end of electric capacity is interconnected to form a common port, common end grounding;

Described step-down transformer T1 comprises 1 armature winding and n secondary winding, and it has n secondary, when the bidirectional switch adopting high pressure IGBT as matrix array, as long as step-down transformer 3 secondary; When the bidirectional switch adopting low pressure IGBT as matrix array, step-down transformer needs 5 to 8 secondary, and the phase place of all secondary of step-down transformer is identical, without phase difference;

The matrix array that the 1 row n that described three-phase---three-phase matrix array A1-An is by n three-phase---three-phase matrix converter forms is capable, wherein each three-phase---three phase matrixs correspond to a secondary of step-down transformer, the three-phase of each three-phase---three-phase matrix converter exports after three-phase isolation transformer isolated variable, its secondary is cascaded, form three-phase high-voltage voltage to export, each matrix converter is connected with controller, regulating and controlling is unified by controller, described three-phase---three-phase matrix converter is by input filter LC1, three-phase-three-phase matrix composition, 3 inductance and 3 electric capacity of described input filter LC1 are connected respectively, the other end of inductance is connected to step-down transformer secondary, the other end of electric capacity is shorted together, and ground connection, described three-phase-tri-phase matrix is by 9 groups of bidirection switching device S11, S12, S13, S21, S22, S23, S31, S32, S33 form, and it forms the matrix of 3*3, described bidirection switching device S11, S12, S13, S21, S22, S23, S31, S32, S33 have 4 kinds of structures,

The former limit of described series connection isolating transformer is all delta connection, and wherein T1 secondary is wye connection, and other secondary is the outlet of three-phase independence, and the former secondary voltage of all isolating transformers is all identical, does not have phase difference.

Described master controller, comprise synchronizing voltage detection control plate, CPU s operation control plate, pulsed drive division board, current/voltage check-out console, velocity measuring plate and logical circuit, synchronizing voltage detection control plate gathers synchronous voltage signal by step-down transformer net end; Current/voltage check-out console detects electric current, voltage live signal by the Hall element of the line side of each matrix unit; Velocity measuring plate detects the rate signal of motor by the photoelectric encoder on motor; All signals are pooled to CPU s operation control plate, and control board, by calculating, drives the bidirectional switch in matrix permutation through pulsed drive division board.Thus ensure that the final output voltage of frequency converter is the amplitude of load needs and the three phase sine alternating current of frequency-adjustable, ensure that input current is three phase AC sine wave.Meanwhile, ensure that energy can two-way flow.

Further, described step-down transformer input high pressure three-phase alternating voltage, the low pressure exporting isolation corresponds to the sub-high pressure three-phase alternating voltage of power device, described often group secondary three-phase alternating voltage corresponds to a secondary three-phase secondary winding, the connection group (or phase place) of three-phase vice-side winding is identical, the input of described three-phase---three-phase inverter unit corresponds respectively to the secondary of step-down transformer, be input as three-phase alternating voltage, export the three-phase alternating voltage for voltage and frequency-adjustable, three-phase---the quantity one_to_one corresponding of three-phase inverter unit in the quantity of described step-down transformer vice-side winding and matrix converter array, the transducer array that all power converter cells composition 1 row n are capable, each matrix converter unit is three-phase matrix converter.The three-phase of each matrix converter unit exports by three-phase isolation transformer coupling output, the three-phase secondary series connection mutually respectively of transformer, first star-like connection of transformer secondary simultaneously.

Further, each three-phase matrixing unit comprises a low voltage filter, three phase matrixs of a 3*3, the modulation matrix of all three-phase matrixing unit is identical, controller gathers synchronizing voltage, detect entering of each matrix unit converter, line voltage electric current, detect speed and the electric current of motor simultaneously, pass through control algorithm, by pulsed drive division board, drive the two-way power switch in matrix unit, like this, according to the needs of load high voltage motor transmission, three-phase matrix converter array can export fundamental voltage amplitude and frequency continuously adjustable high pressure SPWM (sinusoidal pulse width modulation) voltage of three-phase symmetrical, meet the transmission needs of load motor system, obtain sine-shaped input current waveform at electrical network input simultaneously.System is polluted without harmonic current electrical network, in isolating transformer and transducer array, transducer array and step-down transformer, the ability all achieving realizing bidirectional electric energy flow between step-down transformer and electrical network.

Further, described step-down transformer wherein three-phase high-voltage armature winding is connected with the inductance output end of input Three-phase electric-wave filter respectively, and each three-phase secondary winding is connected with a three-phase-three-phase matrix converter unit of in matrix converter permutation respectively.

Further, described three-phase matrix converter array A1-An is identical with the quantity of step-down transformer secondary, the array structure that wherein all three-phase matrix converter unit composition 1 row n are capable, the vice-side winding of step-down transformer is connected with three-phase matrix converter unit respectively, one end of power take-off first three-phase isolation transformer secondary winding after three-phase isolation transformer coupling of each power converter cells links together, form the neutral point exporting three-phase alternating voltage, the other end of first three-phase isolation transformer respectively with once the connecting of other each phases of isolating transformer secondary winding, thus form three-phase alternating voltage output, each matrix converter unit is connected with drived control plate respectively by optical fiber, then received on controller by cable.

Matrix converter unit of the present invention is by low voltage filter, three-phase---and three-phase matrix forms, low voltage filter LC1 is made up of conventional low voltage LC filter, three filter inductances and three filter capacitors are connected respectively, one end of inductance is respectively with three-phase---the input of three phase matrixs is connected simultaneously, the other end of electric capacity is shorted together, and ground connection.

Matrix converter of the present invention is three-phase---three-phase matrix converter, and input is three-phase alternating voltage, and exporting also is three-phase alternating voltage, 9 groups of bidirection switching device S11, S12, S13; S21, S22, S23; S31, S32, S33 form the matrix of 3*3, and three-phase input voltage is Ua, Ub, Uc, and three-phase output voltage is Uu, Uv, Uw, so has following formula:

$\left[\begin{array}{c}\mathrm{Uu}\\ \mathrm{Uv}\\ \mathrm{Uw}\end{array}\right]=\left[\begin{array}{ccc}\mathrm{\σ}11& \mathrm{\σ}12& \mathrm{\σ}13\\ \mathrm{\σ}21& \mathrm{\σ}22& \mathrm{\σ}23\\ \mathrm{\σ}31& \mathrm{\σ}32& \mathrm{\σ}33\end{array}\right]\left[\begin{array}{c}\mathrm{Ua}\\ \mathrm{Ub}\\ \mathrm{Uc}\end{array}\right];$ Wherein, $\left[\begin{array}{ccc}\mathrm{\σ}11& \mathrm{\σ}12& \mathrm{\σ}13\\ \mathrm{\σ}21& \mathrm{\σ}22& \mathrm{\σ}23\\ \mathrm{\σ}31& \mathrm{\σ}32& \mathrm{\σ}33\end{array}\right]$ Be modulation matrix, it is the function of time, and each element is different in each switch periods, and all debugging matrixes of the matrix converter of series connection are indirectly identical, and modulator approach is completely the same.

Controller of the present invention, comprise synchronizing voltage detection control plate, CPU s operation control plate, pulsed drive division board, current/voltage check-out console, velocity measuring plate and logical circuit, synchronizing voltage detection control plate gathers synchronous voltage signal by step-down transformer net end; Current/voltage check-out console detects electric current, voltage live signal by the Hall element of the line side of each matrix unit; Velocity measuring plate detects the rate signal of motor by the photoelectric encoder on motor; All signals are pooled to CPU s operation control plate, and control board, by calculating, drives the bidirectional switch in matrix permutation through pulsed drive division board.Thus ensure that the final output voltage of frequency converter is the amplitude of load needs and the three phase sine alternating current of frequency-adjustable, ensure that input current is three phase AC sine wave.Meanwhile, ensure that energy can two-way flow.

The invention has the beneficial effects as follows: the one that the present invention proposes is connected three-phase matrix form medium-high voltage frequency converter indirectly, there is following outstanding advantages: 1, the present invention is for handing over matrix form Direct Conversion, output voltage is the three phase sine alternating voltage that amplitude and frequency can regulate continuously, input current is also three-phase alternating current sinusoidal current, and power factor is 1 substantially; 2, the high voltage converter that realizes of the present invention, energy can two-way flow, and system can four quadrant running, and system configuration is simple, and energy-saving effect is remarkable; 3, the step-down transformer structure in the present invention is simple, and secondary group is identical, and phase place is identical.If adopt high pressure IGBT to make two-way power switch device, step-down transformer secondary only needs 3 groups, can simplify step-down transformer structure further; 4, do not need DC link in the present invention, this eliminate a large amount of electrochemical capacitors or self-healing electric capacity, system bulk is little, and reduces the wastage.

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention;

Fig. 2 is the schematic diagram of three-phase matrix converter unit in Fig. 1;

Fig. 3 is common collector IGBT two-way power switch schematic diagram in Fig. 2;

Fig. 4 is common emitter IGBT two-way power switch schematic diagram in Fig. 2;

Fig. 5 is IGBT bridge-type two-way power switch schematic diagram in Fig. 2;

Fig. 6 is reverse blocking IGBT two-way power switch schematic diagram in Fig. 2;

Fig. 7 is input filter schematic diagram.

Embodiment

Below in conjunction with accompanying drawing, the present invention is specifically described.Following examples further illustrate of the present invention, and do not form limitation of the invention.

Be described for band 3 secondary step-down transformers of the present invention's design, structure as shown in Figure 1.Be made up of input filter LC, step-down transformer T1, matrixing array A1-A3, isolation series transformer T2-T4 and controller, controller and man-machine interface communication.

Input filter LC, schematic diagram as shown in Figure 7, be made up of three filter inductances and three filter capacitors, the input of three filter inductances is connected on electrical network, its output connects the former limit of three-phase of step-down transformer T1, one end of three filter capacitors is connected with the output of three filter inductances respectively, and the other end is interconnected, and ground connection.

Step-down transformer T1 is shown in Fig. 1, be made up of a former limit of three-phase and three three-phase vice-side winding, it is (Yd11 that transformer connects group, d11, or (Dy11, y11, y11) d11), the former limit of three-phase is connected with three outputs of the filter inductance in input filter LC, and three-phase vice-side winding is connected respectively to the three-phase input end of matrixing array (A1-A3).3 vice-side winding connection groups of step-down transformer are identical, and phase place is identical, and voltage is identical.

As Fig. 1 and Fig. 2, matrixing array A1-A3 is made up of 1 row * 3 row=3 three-phase-three-phase matrix converter unit, the three-phase input end of each power converter cells is connected with step-down transformer secondary three-phase output end, after the three-phase of each three-phase matrix converter is exported and is coupled by three-phase isolation transformer, isolating transformer is every connects mutually successively, 3 row matrix power converter cells export the every overall employing wye connection mutually of three-phase isolating transformer after three-phase isolation transformer coupling, form three-phase high-voltage ac output end and a neutral point N respectively, constitute series connection three-phase matrix form high voltage converter indirectly.Wherein, as Fig. 2, matrix converter unit is three-phase matrix converter, be made up of low voltage filter, three-phase-three-phase matrix, low voltage filter LC1, be made up of conventional low voltage LC filter, three filter inductances and three filter capacitors are connected respectively, one end of inductance is connected with the input of three-phase-tri-phase matrix respectively simultaneously, and the other end of electric capacity is shorted together, and ground connection.Three-phase-three-phase matrix converter input three-phase alternating voltage, export also is three-phase alternating voltage simultaneously, by 9 groups of bidirection switching device S11, S12, S13; S21, S22, S23; S31, S32, S33 form, and form the matrix of 3*3, three-phase input voltage is Ua, Ub, Uc, and three-phase output voltage is Uu, Uv, Uw, so has following formula:

$\left[\begin{array}{c}\mathrm{Uu}\\ \mathrm{Uv}\\ \mathrm{Uw}\end{array}\right]=\left[\begin{array}{ccc}\mathrm{\σ}11& \mathrm{\σ}12& \mathrm{\σ}13\\ \mathrm{\σ}21& \mathrm{\σ}22& \mathrm{\σ}23\\ \mathrm{\σ}31& \mathrm{\σ}32& \mathrm{\σ}33\end{array}\right]\left[\begin{array}{c}\mathrm{Ua}\\ \mathrm{Ub}\\ \mathrm{Uc}\end{array}\right];$ Wherein, $\left[\begin{array}{ccc}\mathrm{\σ}11& \mathrm{\σ}12& \mathrm{\σ}13\\ \mathrm{\σ}21& \mathrm{\σ}22& \mathrm{\σ}23\\ \mathrm{\σ}31& \mathrm{\σ}32& \mathrm{\σ}33\end{array}\right]$ Be modulation matrix, it is the function of time, and each element is different in each switch periods.And all debugging matrixes of the matrix converter of series connection are indirectly identical, modulator approach is completely the same.Bidirection switching device S11, S12, S13; S21, S22, S23; S31, S32, S33 are just like Fig. 3, Fig. 4, Fig. 5, Fig. 6 totally four kinds of different structures, the wherein common collector two-way power switch schematic diagram that is made up of 2 fly-wheel diodes and 2 IGBT of Fig. 3, the common emitter two-way power switch schematic diagram that Fig. 4 is made up of 2 fly-wheel diodes and 2 IGBT, the bridge-type two-way power switch schematic diagram that Fig. 5 is made up of 4 diodes and 1 IGBT and 1 fly-wheel diode, the reverse blocking IGBT two-way power switch schematic diagram that Fig. 6 is made up of 2 IGBT.

Series connection isolating transformer T2-T4, former limit is all delta connection, and wherein T1 secondary is wye connection, and other secondary is the outlet of three-phase independence, and the former secondary voltage of all isolating transformers is all identical, does not have phase difference simultaneously.

Controller comprises the compositions such as synchronizing voltage detection control plate, CPU s operation control plate, pulsed drive division board, current/voltage check-out console, velocity measuring plate and logical circuit.Synchronizing voltage detection control plate gathers synchronous voltage signal by step-down transformer net end; Current/voltage check-out console detects electric current, voltage live signal by the Hall element of the line side of each matrix unit; Velocity measuring plate detects the rate signal of motor by the photoelectric encoder on motor; All signals are pooled to CPU s operation control plate, and control board, by calculating, drives the bidirectional switch in matrix permutation through pulsed drive division board.Thus ensure that frequency converter final output voltage is that amplitude that load needs exchanges with the three phase sine of frequency-adjustable and ensures that input current is three intersect sine waves.Meanwhile, ensure that energy can two-way flow.

Input filter in the present invention, step-down transformer, three-phase matrix array, series connection isolating transformer and controller etc. are inseparable part, can not analyze simply separately, thus form series connection three-phase matrix form middle high-pressure frequency converter indirectly.

Operation principle of the present invention is as follows: adopt ripe matrix converter control algolithm to control indirectly to connect three-phase-three-phase matrixing matrix array.In matrix array each series connection input voltage amplitude of three-phase-three-phase matrixing unit and phase place completely the same, adopt identical modulation matrix simultaneously, ensure every mutually indirectly series connection time its voltage magnitude identical, phase place is identical.Like this, inlet wire high tension voltage is by after filtering, through step-down, then by after the modulation of three-phase-three-phase matrixing unit model identical, generate the three-phase alternating current sinusoidal voltage that amplitude is consistent with phase place, indirectly connecting through isolating transformer, be superimposed as the high pressure three-phase alternating voltage that phase invariant amplitude superposes at double.Because this high voltage converter adopts matrix array, use same-phase to superpose with the low voltage three-phase sinusoidal voltage of amplitude simultaneously, and also have inlet wire filtering and low-voltage filter link, so output voltage waveforms is almost undistorted, output voltage is the three-phase alternating current sinusoidal voltage of amplitude and frequency continuously adjustabe joint, input current is three-phase alternating current sinusoidal current, voltage, current harmonics are little, du/dt is very little, power factor is close to 1, energy capable of bidirectional flowing, energy four quadrant running, can Direct driver mesohigh alternating current motor.Inner without rectifying and wave-filtering link, do not need jumbo electrochemical capacitor or self-healing electric capacity, system inversion efficiency is high.In sum, indirect series connection three-phase matrix form medium-high voltage frequency converter of the present invention can be applied in mesohigh driving by A.C.motor field, comprise 2 quadrants of motor, 4 quadrants run, soft start runs, be applicable to high-power application scenario, have system power factor high, can 4 quadrants run, low, the continuously adjustable feature of output voltage amplitude frequency of harmonic wave of output voltage content.

More than show and describe general principle of the present invention and principal character and advantage of the present invention.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; what describe in above-described embodiment and specification just illustrates principle of the present invention; without departing from the spirit and scope of the present invention; the present invention also has various changes and modifications; these changes and improvements all fall in the claimed scope of the invention, and application claims protection range is defined by appending claims and equivalent thereof.

Claims (1)

1. an indirect series connection three-phase matrix form medium-high voltage frequency converter, is made up of input filter LC, step-down transformer T1, matrixing array A1-A3, isolating transformer T2-T4 and controller, controller and man-machine interface communication;

Input filter LC is made up of three filter inductances and three filter capacitors, the input of three filter inductances is connected on electrical network, its output connects the former limit of three-phase of step-down transformer T1, one end of three filter capacitors is connected with the output of three filter inductances respectively, and the other end is interconnected and ground connection;

Step-down transformer T1 is made up of a former limit of three-phase and three three-phase vice-side winding, step-down transformer T1 connected mode is former limit is star-like connection, secondary is that triangle connects or former limit is that triangle connects, secondary is star-like connection, the former limit of three-phase is connected with three outputs of the filter inductance in input filter LC, three three-phase vice-side winding are connected respectively to the three-phase input end of three matrixing array A1-A3,3 vice-side winding connection groups of step-down transformer T1 are identical, phase place is identical, and voltage is identical;

Matrixing array A1-A3 is by three three-phases---three-phase matrix converter forms, and the three-phase input end of each three-phase---three-phase matrix converter is connected with a three-phase vice-side winding of step-down transformer T1;

The three-phase of each three-phase---three-phase matrix converter exports respectively by a three-phase isolation transformer T2-T4 isolated variable, the former limit of these three isolating transformer T2-T4 is delta connection, secondary is the outlet of three-phase independence, vice-side winding is every connects mutually successively, vice-side winding after series connection finally forms three-phase high-voltage ac output end and a neutral point N of Y connection, all former secondary voltages of isolating transformer T2-T4 are all identical, do not have phase difference simultaneously;

Each three-phase---three-phase matrix converter, by low voltage filter LC1, three-phase---three-phase matrix forms, low voltage filter LC1, be made up of conventional low voltage filter, comprise three filter inductances and three filter capacitors of connecting respectively, one end of three filter inductances of low voltage filter is connected with the input of three-phase-tri-phase matrix respectively, the other end of three filter capacitors of low voltage filter is shorted together, and ground connection, three-phase-three-phase Input matrix three-phase alternating voltage, export also is three-phase alternating voltage simultaneously, by 9 groups of bidirection switching device S11, S12, S13, S21, S22, S23, S31, S32, S33 form, and form the matrix of 3*3, described bidirection switching device S11, S12, S13, S21, S22, S23, S31, S32, S33 are four kinds of different structures,

The three-phase alternating voltage of input is Ua, Ub, Uc, and the three-phase alternating voltage of output is Uu, Uv, Uw, so has following formula: $\left[\begin{array}{c}Uu\\ Uv\\ Uw\end{array}\right]=\left[\begin{array}{ccc}\mathrm{\σ}11& \mathrm{\σ}12& \mathrm{\σ}13\\ \mathrm{\σ}21& \mathrm{\σ}22& \mathrm{\σ}23\\ \mathrm{\σ}31& \mathrm{\σ}32& \mathrm{\σ}33\end{array}\right]\left[\begin{array}{c}Ua\\ Ub\\ Uc\end{array}\right];$

Wherein, $\left[\begin{array}{ccc}\mathrm{\σ}11& \mathrm{\σ}12& \mathrm{\σ}13\\ \mathrm{\σ}21& \mathrm{\σ}22& \mathrm{\σ}23\\ \mathrm{\σ}31& \mathrm{\σ}32& \mathrm{\σ}33\end{array}\right]$ Be modulation matrix, it is the function of time, and each element of modulation matrix is different in each switch periods, and three three-phases---the debugging matrix of three-phase matrix converter is identical, and modulator approach is completely the same;

Controller comprises synchronizing voltage detection control plate, CPU s operation control plate, pulsed drive division board, current/voltage check-out console, velocity measuring plate and logical circuit, and synchronizing voltage detection control plate is netted end by step-down transformer T1 and gathered synchronous voltage signal; Current/voltage check-out console is by each three-phase---and the Hall element of the line side of three-phase matrix converter detects electric current, voltage live signal; Velocity measuring plate detects the rate signal of motor by the photoelectric encoder on motor; All signals are pooled to CPU s operation control plate, control board is by calculating, the bidirectional switch in each matrix array is driven through pulsed drive division board, thus ensure that the final output voltage of frequency converter is the amplitude of load needs and the three phase sine alternating current of frequency-adjustable, ensure that the electric current inputted is three phase AC sine wave, ensure that energy can two-way flow simultaneously.