CN204030997U - A kind of matrix form AC-dc converter - Google Patents

Abstract

The utility model relates to a kind of matrix form AC-dc converter, primarily of formations such as switch matrix, input voltage detection circuit, control circuit, input filter circuit, power switch driver circuits.This utility model adopts a step change of current, by 2 IGBT power switch differential concatenation composition bidirectional switchs, achieves output voltage continuously adjustabe, can realize four quadrant running under unit power.This utility model circuit structure is simple, is easy to realize, and has the superior functions such as input current is sinusoidal quantity, to and fro flow of power, power factor (PF) is adjustable, output voltage continuously adjustabe, on-off times significantly reduce.Can be used for the occasions such as the four quadrant running of direct current machine, DC excitation, power factor correction.

Description

A kind of matrix form AC-dc converter

Technical field

The utility model relates to AC/DC convertor technical field, is specifically related to the matrix form AC-dc converter that can realize four quadrant running that a kind of PWM of taking controls.

Background technology

Conventional rectifier device uses uncontrollable or half control type device, and its make-and-break time is uncontrollable or not exclusively controlled.The uncontrollable rectifying device utilizing diode to form has obvious shortcoming, as non-adjustable in output dc voltage, make input current waveform Severe distortion, power factor of electric network very low, and determines its energy one-way flow only due to the unilateral conduction of diode.Although and adopt the phase controlled rectifier of thyristor to solve the nonadjustable shortcoming of output voltage, but because it adopts phased approach to control, still there is the problems such as input current Severe distortion, input power factor are low, simultaneously also cannot conduct reverse current, load can only realize two quadrants and run.Along with increasing conventional rectifier equipment investment uses, power electronic equipment has become the main harmonic pollution source in electrical network, and among various converter, rectifying installation is again the main source of harmonic pollution.Meanwhile, the power factor that conventional rectifier is lower makes electrical network have to carry out extra reactive power compensation, adds extra compensation equipment, complex structure, and this economical operation for electrical network will produce totally unfavorable impact.Meanwhile, nowadays many direct current machines require forward and backward can to realize fast braking again, and this just requires that DC power supply has the ability of four quadrant running, and obviously traditional rectifying installation cannot meet this requirement.

Utility model content

The utility model is in order to solve prior art above shortcomings, and provide a kind of structure simple, be easy to the matrix form AC-dc converter realized, concrete technical scheme is as follows.

A kind of matrix form AC-dc converter, comprise input filter circuit and the input voltage detection circuit be connected in turn, control circuit, drive circuit, switch matrix, the wherein input termination three-phase alternating current of input filter circuit, the output of input filter circuit is connected with the input of switch matrix, drive circuit is connected with switch matrix, the input of input voltage detection circuit connects three-phase alternating current, described switch matrix adopts six bidirectional switchs to connect into three-phase H bridge, this matrix form AC-dc converter realizes three-phase alternating current input, and single-phase DC exports.

Further, each bidirectional switch in described switch matrix forms by a pair full-control type power switch.

Further, each bidirectional switch is made up of the IGBT of 2 differential concatenations.

Further, described input voltage detection circuit adopts Hall voltage transducer to form.

Further, control circuit is made up of TMS320F28335 chip (DSP) and EP4CE6 chip (FPGA), realizes the adjustment to output voltage amplitude and polarity.PWM control strategy taked based on current space vector control algolithm by described control circuit, and (this control algolithm is prior art, be widely used in Motor Control Field, belong to known a kind of control algolithm), and utilize the testing result of input voltage detection circuit, by the computing of control circuit completion logic, realize a step change of current to control, control signal carries out power amplification rear drive bidirectional switch by drive circuit, and the optocoupler components utilizing driving chip to carry achieves Phototube Coupling.

Further, described drive circuit adopt ACPL 332J driving chip, carry Phototube Coupling function and fault-signal exports, the fault-signal termination of drive circuit enters control circuit, when control circuit receives fault-signal, send control signal by automatically stopping to drive circuit.

Compared with prior art, the utility model tool has the following advantages and technique effect:

The utility model circuit structure is simple, is easy to realize.The utility model discloses a kind of matrix form Jiao Liu DC converter, Hall voltage transducer is utilized to form input voltage detection circuit, detect phase voltage and line voltage zero-cross point by existing algorithm (based on current space vector control algolithm) to realize carrying out subregion to the input AC electricity cycle, impose suitable PWM to 6 different sectors again to control, the final PWM realized based on current space vector strategy controls.Conventional rectifier device uses uncontrollable or half control type device, and the utility model adopts a step change of current, by 2 IGBT power switch differential concatenation composition bidirectional switchs, achieves output voltage continuously adjustabe, can realize four quadrant running under unit power.The utility model not only structure is simple, and on-off times can be made significantly to reduce, and control circuit adopts DSP+FPGA to form dual-core architecture, provides circuit working efficiency and stability.The utility model can be used for the occasion such as four quadrant running, DC excitation, power factor correction of direct current machine.

Accompanying drawing explanation

Fig. 1 is the topological structure of ac/dc matrix converter.

Fig. 2 is the connection layout that in example, IGBT is composed in series bidirectional switch.

Fig. 3 is the synthesis schematic diagram of target current vector in example.

Fig. 4 is duty ratio discretization logic diagram in example.

Fig. 5 is matrix form AC-dc converter circuit block diagram.

Fig. 6 is IGBT drive circuit figure in example.

Embodiment

Below in conjunction with accompanying drawing, embodiment of the present utility model is described in further detail; need it is emphasized that; below be only preferred embodiments of the present utility model; and be not used in restriction protection range of the present utility model; in addition; if have symbol or the control procedure of special detailed description, be all that those skilled in the art can with reference to existing techniques in realizing.

As shown in Figure 5, a kind of matrix form AC-dc converter, comprise input filter circuit and the input voltage detection circuit be connected in turn, control circuit, drive circuit, switch matrix, the wherein input termination three-phase alternating current of input filter circuit, the output of input filter circuit is connected with the input of switch matrix, drive circuit is connected with switch matrix, the input of input voltage detection circuit connects three-phase alternating current, described switch matrix adopts six bidirectional switchs to connect into three-phase H bridge, this matrix form AC-dc converter realizes three-phase alternating current input, single-phase DC exports.As shown in Figure 1,6 two-way power switch (S11, S12, S13, S21, S22, S23) such as figure is connected into three-phase H bridge type structure, three-phase alternating current inputs, and single-phase DC exports.This example adopts the mode of 2 IGBT series connection to form a two-way power switch, and concrete connected mode as shown in Figure 2.

To the equipment shown in Fig. 1, only successively need distribute driving pulse according to existing control strategy by control circuit to switch matrix, can obtain that polarity is adjustable, amplitude is controlled, the output of the direct current of unit power factor, input current waveform sineization.And this example is taked is current space vector modulation algorithm (the known a kind of algorithm be widely used), in order to make the public clearly, illustrate to execution mode below, matrix form AC-dc converter circuit block diagram as shown in Figure 5.

First three-phase is inputted phase current and obtain input phase current vector through Park conversion .

Park converts: $\stackrel{\→}{I}=\frac{2}{3}(I_a+I_b\mathrm{\ρ}+I_c{\mathrm{\ρ}}^2)$

I in above formula _a, I _b, I _cbe respectively a, b, c three-phase current, ρ=e ^{j120 °}

6 switches one in main circuit have the combination of 9 kinds of on off operating modes, carry out Park conversion and can obtain 9 kinds of current phasors often organizing under on off state.Switch combination and current phasor, output voltage are as shown in table 1.

Table 1

An ac period average mark is slit into 6 sectors by the current phasor of 6 kinds of non-zeros, and the zero crossing of separation between sector certain phase current corresponding.And current mode space vector modulation utilizes two non-zero synthesis to obtain target vector.(as shown in Figure 3).

Final goal current phasor is $\stackrel{\→}{I_{\mathrm{ref}}}=\frac{T_{\mathrm{\α}}\left(\mathrm{\θ}\right)}{T_s}\stackrel{\→}{I_a}+\frac{T_{\mathrm{\β}}\left(\mathrm{\θ}\right)}{T_s}\stackrel{\→}{I_{\mathrm{\β}}}+\frac{T_0\left(\mathrm{\θ}\right)}{T_s}\stackrel{\→}{I_0}$

and the relation of θ as shown in Figure 3, utilize control circuit can synthesize the current phasor required for us by the adjustment of duty ratio.

Complete current phasor synthesis and first need computed duty cycle, and computed duty cycle needs first to obtain current phasor phase angle theta.Because general running status always wishes input phase current and input phase voltage homophase, therefore this example current testing circuit determines the phase angle of current phasor by the phase angle detecting phase voltage vector.Azimuth generates and completes by following algorithm.

In above formula: V _dfor D shaft voltage component, V _qfor Q shaft voltage component, ω _ifor input angle frequency, V _a, V _b, V _cfor a, b, c three-phase phase voltage.

After obtaining azimuth, utilize duty ratio computing module can obtain synthesizing the duty ratio d used by target current vector _α, d _β, d ₀.Duty ratio computing function is as follows:

d _α(θ _in)＝m·sin[60°-(θ _inmod60°)]

d _β(θ _in)＝m·sin[(θ _inmod60°)]

d ₀(θ _in)＝1-d _α(θ _in)-d _β(θ _in)

In above formula, mod is complementation computing, θ _infor the input vector phase angle of aforementioned phase angle generation module gained, m is current-modulation degree.The output d of duty ratio computing module _α, d _β, d ₀for continuous signal, for the switching signal of 1 needed for bidirectional switch and 0 composition must be controlled, sliding-model control need be carried out to duty ratio.Duty ratio sliding-model control logic as shown in Figure 4.

Current space vector modulation algorithm selects different non-vanishing vectors to synthesize for the target current vector in different sector, namely different sectors, and pulse should be dispensed to different switches.Determine pulse distribution rule, must first obtain current phasor sector number.Positive and negative for phase voltage polarity represents with 1,0 by this example, achieves the binary coding of input phase voltage.Recycling binary coding is carried out decoding and is obtained decimal coded, and decoding table is as follows:

A phase: 1 → 0 saltus step, exports as sector 30 → 1 saltus step, exports as sector 6

B phase: 1 → 0 saltus step, exports as sector 50 → 1 saltus step, exports as sector 2

C phase: 1 → 0 saltus step, exports as sector 10 → 1 saltus step, exports as sector 4

Can carry out pulse distribution according to pulse distribution table after acquisition sector number, pulse distribution table is as follows:

In table, I1 ~ I6 represents the sector residing for current phasor, is obtained by above-mentioned input current sector judge module, and input current sector judge module only has the corresponding vector in current sector to be 1 in exporting, all the other are 0.And V and then determined by the polarity of output voltage, the V=1 when needs output cathode, the V=0 when needs output negative pole,

By said method, (contents of program of the method is the digitlization of known current space vector algorithm, belong to existing content, but the formation structure of control circuit is innovation of the present utility model) achieve current space vector modulation to matrix switch, achieve the effective adjustment to input current waveform, effectively solve current distortion problem.Can realize the continuously adjustabe of output voltage and the two-way flow of energy by the value of modulation degree m in setting controller and polarity of voltage V, therefore this example has the ability of four quadrant running.For duty ratio computing module, if input phase voltage azimuth, achieve phase current and phase voltage same-phase, if increase input phase voltage azimuth or reduce arbitrarily angled, then can regulate power factor.

The pwm control signal generated due to above-mentioned control circuit does not have enough electric currents, voltage driving capability, and powerful IGBT cannot be driven to manage, therefore for IGBT provides the voltage matched with it to ensure that it is opened normally and turns off.This example selects ACPL 332J chip to form drive circuit, and connected mode as shown in Figure 6.Utilize ACPL the photoisolator that carries of 332J effectively to input, export and carried out electrical isolation.

In Fig. 6, PWM drive singal is sent by control circuit, and FAULT end is fault-signal output, in access control circuit, as the triggering signal of element protection.Symbol in Fig. 6 and be labeled as chip self with general mark and symbol, do not repeat them here.

Control circuit adopts DSP+FPGA to form dual-core architecture, is made up of a slice TMS320F28335 DSP chip and a slice EP4CE6 programmable logic device.DSP has very strong digital signal operational capability, is suitable for very much high speed combine digital algorithm.FPGA then has powerful logical operation capability, is applicable to complicated logical operation process.Control circuit DSP performs current space vector modulation algorithm, obtains duty ratio.Perform pulse distribution logical operation by FPGA again, control impuls is dispensed to corresponding driving chip.And the fault-signal output of driving chip feeds back to the I/O mouth of FPGA, once FPGA receives fault-signal, then FPGA will perform defence program, stop the output of control impuls.

This dual-core architecture of control circuit makes it have the logical operation capability of DSP digital processing capabilities and FPGA complexity fast concurrently, well can complete control task, and provides defencive function for matrix switch.

Claims (6)

1. a matrix form AC-dc converter, it is characterized in that comprising input filter circuit and the input voltage detection circuit be connected in turn, control circuit, drive circuit, switch matrix, the wherein input termination three-phase alternating current of input filter circuit, the output of input filter circuit is connected with the input of switch matrix, drive circuit is connected with switch matrix, the input of input voltage detection circuit connects three-phase alternating current, described switch matrix adopts six bidirectional switchs to connect into three-phase H bridge, this matrix form AC-dc converter realizes three-phase alternating current input, single-phase DC exports.

2. a kind of matrix form AC-dc converter as claimed in claim 1, is characterized in that each bidirectional switch in switch matrix forms by a pair full-control type power switch.

3. a kind of matrix form AC-dc converter as claimed in claim 1, is characterized in that each bidirectional switch is made up of the IGBT of 2 differential concatenations.

4. a kind of matrix form AC-dc converter as claimed in claim 1, is characterized in that control circuit is made up of TMS320F28335 chip and EP4CE6 chip, realizes the adjustment to output voltage amplitude and polarity.

5. a kind of matrix form AC-dc converter as claimed in claim 1, it is characterized in that described drive circuit adopt ACPL 332J driving chip, carry Phototube Coupling function and fault-signal output, the fault-signal termination of drive circuit enters control circuit, when control circuit receives fault-signal, send control signal by automatically stopping to drive circuit.

6. a kind of matrix form AC-dc converter as claimed in claim 1, is characterized in that described input voltage detection circuit adopts Hall voltage transducer to form.