CN102223090B - High-power simplified electrolytic and electroplating high-frequency switch power supply and control method thereof - Google Patents

Abstract

The invention discloses a high-power simplified electrolytic and electroplating high-frequency switch power supply and a control method thereof. The simplified electrolytic and electroplating high-frequency switch power supply comprises a three-phase inverter based on three phases and two arms, and a high-frequency DC/DC converter that is formed by serially connecting a single-phase half-bridge inverter, a high-frequency coupling transformer and a low-voltage full-wave rectifier; the three-phase inverter based on the three phases and two arms is formed by connecting two switch arms and two serially-connected capacitor branches at the direct-current side in parallel; the single-phase half-bridge inverter is formed by connecting a switch arm and two serially-connected capacitor branches at the direct-current side in parallel; the three-phase inverter and the single-phase half-bridge inverter commonly share one group of direct-current side capacitors; the input terminal of the three-phase inverter is connected with a power network by a three-phase inductor L; and the output terminal of the three-phase inverter is connected with the single-phase half-bridge inverter. The switch power supply has few switch devices, small loss, high efficiency, small direct-current ripples, high response speed and small voltage distortion and current distortion. The method in the invention has the advantages of improving the response speed of the three-phase inverter and tracking the change of the load power in real time.

Description

High-power reduced form metallide high frequency switch power and control method thereof

Technical field

The present invention relates to Switching Power Supply and control method thereof, specifically is a kind of high-power reduced form metallide high frequency switch power and integrated control method thereof.

Background technology

In the application and various power-supply system of power electronic technology, switch power technology all is in core status.At electric automobile, in Frequency Drive and the metallide industry, be unable to do without switch power technology especially, change the electricity consumption frequency through Switching Power Supply, be bordering on desirable load matched and drive controlling thereby reach.Traditional thyristor or diode rectifier circuit are very huge and heavy; If adopt a high switch power technology; Its volume and weight all can descend significantly, and can greatly improve power utilization efficient, saves material, reduces cost, and realizes that high efficiency electricity consumption and high-quality electricity consumption combine.

To the large-scale electrolysis electroplating power supply; Tradition is electroplated the electrolysis direct current power supply and is adopted Thyristor Controlled rectification pattern; So it is low to work as thyristor operating angle one-hour rating factor, it is big that electrical network is produced harmonic content, directly causes being equipped with power transformer, connects capacity increases such as lead, switch; General silicon controlled rectifier capacious also need increase extra harmonic wave control and power factor compensation device, makes user's overall cost of ownership increase greatly.

The present invention adopts a kind of three-phase rectifier to carry out efficient PWM rectification.Utilize the high-frequency PWM modulation, opening and the turn-off time of control switch pipe realizes the purpose of DC side pressure regulation; Its power factor is very high, generally can reach more than 0.95, and harmonic content is also little; Has the control precision height, good output waveform, characteristics such as energy saving.The DC/DC conversion side of high frequency switch power adopts a kind of single-phase semi-bridge inversion device; The topological structure that high-frequency coupling transformer and low pressure full-wave rectifier constitute; It can become high-frequency alternating current with dc inverter; Convert the voltage and current signal of expectation then into through the low pressure full-wave rectifier, so it can realize the high efficiency of transmission of energy, improve the efficient of Switching Power Supply greatly.In addition, high frequency switch power requires also littler to net capacity, same big power supply, and required net capacity can reduce 20-30%.Therefore, high frequency switch power control is fast with its speed, voltage stabilizing/precision of steady current is high, power factor (PF) and efficient is high, ripple coefficient is low, and the electroplating power supply quality is more had superiority, and becomes the important selection of Switching Power Supply.

Summary of the invention

Technical problem to be solved by this invention is; Not enough to prior art, the high-power reduced form metallide high frequency switch power that a kind of switching device is few, loss is little, efficient is high, response speed is fast, the electric current and voltage distortion is little is provided, and a kind of integrated control method of this high frequency switch power is provided; Improve the response speed of three-phase rectifier; The variation of real-time tracking bearing power, and the PWM rectification of realization three-phase rectifier High Power Factor reach the efficient utilization of electric energy; Reduce the voltage and current aberration rate of system, improve the high frequency switch power operating efficiency greatly.

For solving the problems of the technologies described above; The technical scheme that the present invention adopted is: a kind of high-power reduced form metallide high frequency switch power; Comprise three-phase rectifier based on three-phase two arms; By the single-phase semi-bridge inversion device, the high frequency DC/DC converter that high-frequency coupling transformer and low pressure full-wave rectifier are composed in series, said three-phase rectifier based on three-phase two arms is composed in parallel by two switch arms and DC side two series capacitance branch roads; The single-phase semi-bridge inversion device is composed in parallel by a switch arm and DC side two series capacitance branch roads; Both shared one group of dc bus capacitors, the input of three-phase rectifier links to each other with electrical network through three pole reactor L, and the output of three-phase rectifier links to each other with the single-phase semi-bridge inversion device.

The step of the control method of described high-power reduced form metallide high frequency switch power is:

1) detects dc voltage u _DcWith set-point U _RefAfter subtracting each other, regulate pressure regulation command signal I of back output through the PI controller _Out

2) detect DC side bearing power P _D, calculate the phase current magnitude of three-phase side according to principle of energy balance, be feedforward command signal I _S:

I _S=2P _D/3U

Wherein, U is the phase voltage amplitude of three-phase side;

3) the command signal I that will feedover _SWith pressure regulation command signal I _OutThe synchronizing signal of each phase is multiply by in stack then respectively, and the two phase switch arm current reference signals of trying to achieve based on the three-phase rectifier of three-phase two arms are:

4) detect DC side two capacitance voltage differences, obtain one after regulating through a PI controller and all press conditioning signal I _D, the total reference signal of circular current in this is all pressed conditioning signal directly to be added to constitute on the current reference signal:

$\left\{\begin{array}{c}{i}_{\mathrm{ar}}=i_{\mathrm{da}}+I_D\\ i_{\mathrm{br}}=i_{\mathrm{db}}+I_D\end{array}\right.;$

5) according to the voltage-current relationship and the dead beat control principle of three-phase rectifier, try to achieve the duty cycle signals of two switch arms of three-phase rectifier, expression formula is following:

$\left\{\begin{array}{c}{d}_a=\frac{1}{u_{\mathrm{dc}}}{V}_{\mathrm{Sac}}-\frac{2L}{u_{\mathrm{dc}}}\frac{i_{\mathrm{Sa}}-i_{\mathrm{ar}}}{T}-\frac{L}{u_{\mathrm{dc}}}\frac{i_{\mathrm{Sb}}-i_{\mathrm{br}}}{T}+\frac{1}{2}\\ d_b=\frac{1}{u_{\mathrm{dc}}}{V}_{\mathrm{Sbc}}-\frac{L}{u_{\mathrm{dc}}}\frac{i_{\mathrm{Sa}}-i_{\mathrm{ar}}}{T}-\frac{2L}{u_{\mathrm{dc}}}\frac{i_{\mathrm{Sb}}-i_{\mathrm{br}}}{T}+\frac{1}{2}\end{array}\right.$

Wherein, T is a control cycle; L is the grid side outputting inductance; V _SacAnd V _SbcBe grid line voltage; i _SaAnd i _SbA, B two phase input currents for three-phase rectifier;

6) through the PWM modulator approach, according to duty ratio d _aAnd d _b, try to achieve the switching signal that the arm switch pipe left by two of three-phase rectifier, the driving switch arm obtains the voltage and current signal of expectation.

Current/voltage double loop control to said high frequency DC/DC converter using may further comprise the steps:

1) detects load DC side current i _o, testing result and set-point I _rSubtract each other,, obtain direct current outer shroud control output through PI controller and amplitude limit link

2) detect load dc voltage V _o, testing result and set-point

Subtract each other,, obtain voltage inter-loop control output, be the duty cycle signals d of half-bridge inverter through PI controller and amplitude limit link _o

3) through the high-frequency PWM modulation, obtain the control signal of single-phase semi-bridge inversion device switching device, driving switch is in control the output voltage current signal of expectation.

The amplitude limit link is that the amplitude of exporting signal is limited in certain scope, and promptly after input signal surpasses or is lower than a certain reference value, output voltage will be limited in a certain threshold value, and not change with input voltage.

Three-phase alternating current obtains dc voltage and current after carrying out the PWM rectification through three-phase rectifier.Through the single-phase semi-bridge inversion device dc inverter is become high-frequency ac, transform to secondaryly then through the high-frequency coupling transformer, obtain the output voltage magnitude of current that needs through low pressure full-wave rectifier rectifying and wave-filtering again.Wherein, the three-phase rectifier AC side is connected to electrical network through inductance, and its output is through dc bus capacitor C ₁, C ₂Be connected with the single-phase semi-bridge inversion device.With respect to general high-power high-frequency switch power supply; Three-phase rectifier and the shared one group of dc bus capacitor of half-bridge inverter based on three-phase two arms proposed by the invention; Reduced by 4 power switch pipes like this, reduced the cost and the loss of system, improved the reliability of device.

Three-phase rectifier is through adopting a kind of dead-beat control method based on the bearing power feedforward; Improve the response speed of three-phase rectifier; The variation of real-time tracking bearing power realizes the PWM rectification of rectifier High Power Factor, realizes the efficient utilization of electric energy; And reduce the electric current and voltage aberration rate of system, thereby improve the Switching Power Supply operating efficiency greatly.To by single-phase inverter; The high frequency DC/DC converter that high-frequency coupling transformer and low pressure full-wave rectifier constitute; Through adopting a kind of current/voltage double loop control; Realize the constant voltage and the constant current output of high frequency DC/DC converter, and have the ability that suppresses current disturbing, improve the reliability of device.

The invention has the beneficial effects as follows: the high-power high-frequency switch power supply adopts high-frequency PWM commutation technique and high-frequency inversion technology, compares with diode rectifier, has the control precision height; Good output waveform, energy saving, power factor is high, harmonic content is low; Isolation is strong, characteristics such as modular construction; With respect to general high-power high-frequency switch power supply; Three-phase rectifier and the shared one group of dc bus capacitor of half-bridge inverter based on three-phase two arms proposed by the invention; Reduced by 4 power switch pipes on the whole, reduced the cost and the loss of system, improved the reliability of device; Three-phase rectifier is through adopting a kind of dead-beat control method based on the bearing power feedforward; Improved the response speed of three-phase rectifier; The variation of real-time tracking bearing power, and the PWM rectification of realization three-phase rectifier High Power Factor reach the efficient utilization of electric energy; And reduce the voltage and current aberration rate of system, thereby improve the high frequency switch power operating efficiency greatly; High frequency DC/DC converter using current/voltage double loop control realizes the stable of output DC stream voltage, suppresses the disturbance of electric current and voltage, improves the Switching Power Supply reliability.

Description of drawings

Fig. 1 is general large power, electrically electrolytic plating high frequency switch power structure;

Fig. 2 is high-power reduced form metallide high frequency switch power structure;

Fig. 3 is the dead beat control block diagram of three-phase rectifier based on the power feedforward;

Fig. 4 is the equivalent model of separate unit high frequency DC/DC converter;

Fig. 5 is the current/voltage dicyclo control block diagram of high frequency DC/DC inverter.

Wherein:

1: based on the three-phase rectifier of three-phase two arms; 2: the single-phase semi-bridge inversion device; 3: the high-frequency coupling transformer; 4: full-wave rectifier; 5: three-phase rectifier; 6: single-phase full-bridge inverter.

Embodiment

Referring to Fig. 1, be general large power, electrically electrolytic plating high frequency switch power structure chart.Comprise three-phase rectifier 5, single-phase full-bridge inverter 6, high-frequency coupling transformer 3 and low pressure full-wave rectifier 4.Three-phase rectifier 5 is that 6 power switchs are formed by 3 switch arms, and it exchanges input side and is incorporated into the power networks through three pole reactor L, and its DC side passes through capacitor C _dConnect the next stage circuit.Among the figure, single-phase full-bridge inverter 5, high-frequency coupling transformer 3 constitutes high frequency DC/DC converter with low pressure full-wave rectifier 4.Wherein, single-phase full-bridge inverter 6 is that 4 power switchs are formed by 2 switch arms.

After the three-phase alternating current process three-phase rectifier PWM rectification, obtain constant DC.Then; Carry out high-frequency inversion through full-bridge inverter, convert direct current into high-frequency alternating current, through the high-frequency coupling transformer; Energy is transferred to low pressure full-wave rectification side from DC side, supplies power to high power load through the dc voltage and current that obtains hoping behind the full-wave rectifier rectifying and wave-filtering.

Referring to Fig. 2, be high-power reduced form metallide high frequency switch power structure chart.Comprise three-phase rectifier 1, single-phase semi-bridge inversion device 2, high-frequency coupling transformer 3 and low pressure full-wave rectifier 4 based on three-phase two arms.Wherein, based on the three-phase rectifier 1 of three-phase two arms, be made up of 2 switch arms and two dc capacitors, it exchanges input side and is incorporated into the power networks through three pole reactor L, and its DC side connects the next stage circuit through selfcapacity.Among the figure, single-phase semi-bridge inversion device 2, high-frequency coupling transformer 3 constitutes high frequency DC/DC converter with low pressure full-wave rectifier 4.Wherein, single-phase semi-bridge inversion device 2 is a half-bridge structure, is made up of 1 switch arm and two dc bus capacitors.It is thus clear that, novel three-phase rectifier 1 and single-phase semi-bridge inversion device 2 shared one group of dc bus capacitor, and both reduce by a switch arm simultaneously.General relatively high frequency switch power structure, this reduced form structure can be accomplished identical functions in advance down, and does not change under the voltage withstand class condition of device, saves the pair of switches arm, is 4 merit switching tubes.Like this, can reduce the device cost of system, the structure of simplified system and circuit design reduce plant energy consumption, improve the reliability and the efficient of device.

Three-phase alternating current obtains direct current after carrying out the high-frequency PWM rectification through the three-phase rectifier based on three-phase two arms.Through adopting based on the dead-beat control method of bearing power feedforward and the quick response and the High Power Factor rectification of high-frequency PWM modulation technology rectifier, realize the efficient utilization of energy, reduce the electric current and voltage aberration rate of system.Then, half-bridge inverter adopts the high-frequency inversion technology, converts direct current into high-frequency alternating current, through the high-frequency coupling transformer, energy is transferred to low pressure full-wave rectification side from DC side, through the dc voltage and current that obtains hoping behind the full-wave rectifier rectifying and wave-filtering.High frequency DC/DC variator is realized the efficient output of energy through adopting the high-frequency inversion technology, reduces the energy consumption of device self, improves the operating efficiency of high frequency switch power greatly.

Among the figure, V _Sa, V _Sb, V _ScBe respectively the grid side phase voltage, L is a filter inductance, C ₁And C ₂Be dc bus capacitor, i _Sa, i _Sb, i _ScInterchange end output current for three-phase rectifier.The C of three-phase rectifier is directly connected to the mid point of two dc capacitors mutually.The voltage that bears of power semiconductor is the half the of DC bus-bar voltage.In each brachium pontis, two effective on off states can produce two kinds of voltages in the alternating voltage side.Two kinds of switching functions are following to deserved each brachium pontis output state:

If we suppose that the capacitance voltage of dc bus equates, it is following then to exchange terminal voltage:

$\left\{\begin{array}{c}{V}_{\mathrm{ao}}=V_a-V_o=g_a*\frac{u_{\mathrm{dc}}}{2}\\ V_{\mathrm{bo}}=V_b-V_o=g_b*\frac{u_{\mathrm{dc}}}{2}\\ V_{\mathrm{ab}}=V_{\mathrm{ao}}-V_{\mathrm{bo}}=(g_a-g_b)*\frac{u_{\mathrm{dc}}}{2}\end{array}\right.---\left(2\right)$

Because the control of two switch arms is independent, can be not each other the output voltage of switch arm separately, export so this three-phase rectifier has 4 kinds of state of a controls, the on off state of three-phase rectifier and the relation of its output voltage are as shown in the table:

The switch control table of the novel three-phase rectifier of table 1:

According to circuit shown in Figure 2, following voltage-current relationship is arranged:

$\left\{\begin{array}{c}L\frac{{\mathrm{di}}_{\mathrm{Sa}}}{\mathrm{dt}}=V_{\mathrm{Sa}}-V_{\mathrm{ao}}+L\frac{{\mathrm{di}}_{\mathrm{Sc}}}{\mathrm{dt}}-V_{\mathrm{Sc}}\\ L\frac{{\mathrm{di}}_{\mathrm{Sb}}}{\mathrm{dt}}=V_{\mathrm{Sb}}-V_{\mathrm{bo}}+L\frac{{\mathrm{di}}_{\mathrm{Sc}}}{\mathrm{dt}}-V_{\mathrm{Sc}}\end{array}\right.---\left(3\right)$

Referring to Fig. 3, be the dead beat control block diagram of three-phase rectifier based on the bearing power feedforward.The rectifier that the present invention adopts is a kind of rectifier based on three-phase two arms, is made up of two power switch arms and one group of dc capacitor, and general relatively three-phase rectifier has reduced by a power switch arm.The 3rd arm of rectifier is composed in series by two dc capacitors, and the electric capacity mid point is connected with electrical network C through inductance.There is the problem of an equal equilibrium in DC side like this; The stable influence that is easy to receive grid disturbance and departure of two capacitance voltages is unfavorable for the long-term stability operation of device, therefore; The control method that we have adopted a kind of DC side all to press realizes the homeostasis of two dc capacitors.In order to realize the efficient operation of system, the present invention proposes a kind of dead-beat control method based on the bearing power feedforward, through the feedforward of bearing power, can improve the dynamic response performance of rectifier, the variation of real-time tracking bearing power; Through adopting dead-beat control method, can realize that the quick indifference of instruction current signal is followed the tracks of, and utilize the high-frequency rectification technology of High Power Factor, realize the efficient utilization of electric energy, reduce the electric current and voltage distortion of system.Being achieved as follows of concrete control method:

Suppose that carrying out the PWM rectification through three-phase rectifier gives the DC side electric, the power of DC side load is P _DUnder the ideal situation, think that the switching loss of system is 0, then following formula arranged according to energy balance principles:

$\frac{3\mathrm{UI}\cos \mathrm{\θ}}{2}=P_D---\left(4\right)$

U wherein, I and θ are respectively phase voltage amplitude, phase current magnitude and the power-factor angle of three-phase side.The power-factor angle θ desired value of three-phase PWM rectification under the ideal situation is 0, then has the three phase network current amplitude of expectation to be:

I _S=2P _D/3U (5)

Can calculate feedforward command signal I like this _S, be the expectation amplitude of three phase network electric current, through feed-forward mode, can realize the quick response of rectifier, follow the tracks of the variation of bearing power.

In order to keep the loss of stablizing and remedy power switch pipe of dc voltage, adopt a pi regulator to realize the closed-loop adjustment of dc voltage outer shroud:

$I_{\mathrm{out}}=k_{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000068997980000021.png"\; state="\{\{state\}\}">P</figure-callout>}1}\mathrm{\&Delta;}{u}_{\mathrm{dc}}+{\mathrm{<figure-callout\; id="1"\; label="k\; I"\; filenames="HDA0000068997980000021.png"\; state="\{\{state\}\}">k</figure-callout>}}_I\&Integral;\mathrm{\&Delta;}{u}_{\mathrm{dc}}\mathrm{dt}---\left(6\right)$

Wherein, I _OutBe outer loop voltag PI controller output; k _P1And k _I1Be ratio and integral coefficient; Δ u _Dc=U _Ref-u _DcBe valtage following.Utilize I _OutCarry out the compensation of dc voltage energy, keep the stable of dc voltage, if the switching tube power loss take jointly by switch arm separately, then with I _OutMultiply by the synchronizing signal of each phase respectively, can obtain the pressure regulation command signal of rectifier two phase power switch arms.The synchronizing signal of each phase is multiply by in the stack of the command signal that will feedover like this and pressure regulation command signal respectively, then can push away to such an extent that the current reference signal of two-phase switch arm of three-phase two arm rectifiers is:

Because DC side is made up of two series capacitances, has an equal equilibrium problem of DC side.The present invention adopts a kind of pressure equalizing control method, is about to the difference (V of two capacitance voltages _C1-V _C2), regulate one of back output through a PI controller and all press regulating command I _D, constituted the total reference signal of interior circular current in this instruction directly is added on the circular current reference signal:

$\left\{\begin{array}{c}{i}_{\mathrm{ar}}=i_{\mathrm{da}}+I_D\\ i_{\mathrm{br}}=i_{\mathrm{db}}+I_D\end{array}\right.---\left(8\right)$

To all press regulating command directly be added in the circular current reference signal, have a mind to change the discharge and recharge effect of the input current of three-phase rectifier to electric capacity, can realize the dynamic equalization of two dc capacitor voltages.

When supposing stable state, three-phase rectifier output three-phase voltage and electric current are balances, and do not have the neutral line, and then instantaneous three-phase voltage and line current sum are zero, can obtain:

i _Sc=-(i _Sa+i _Sb) (9)

Formula (3) and formula (9) above the associating under stable state, according to the average on-off principle of bipolarity modulation, exchange the mean value V of terminal voltage _AoAnd V _BoCan express as follows:

$\left[\begin{array}{c}{V}_{\mathrm{ao}}\\ V_{\mathrm{bo}}\end{array}\right]=\left[\begin{array}{c}(2d_a-1)\frac{u_{\mathrm{dc}}}{2}\\ (2d_b-1)\frac{{\mathrm{<figure-callout\; id="2"\; label="u\; dc"\; filenames="HDA0000068997980000012.png,HDA0000068997980000021.png"\; state="\{\{state\}\}">u</figure-callout>}}_{\mathrm{dc}}}{2}\end{array}\right]=\left[\begin{array}{c}{V}_{\mathrm{Sac}}-L\frac{d}{\mathrm{dt}}(2i_{\mathrm{Sa}}+i_{\mathrm{Sb}})\\ V_{\mathrm{Sbc}}-L\frac{d}{\mathrm{dt}}(i_{\mathrm{Sa}}+2i_{\mathrm{Sb}})\end{array}\right]---\left(10\right)$

Wherein, d _aAnd d _bBe duty ratio, and d _aAnd d _b∈ [0,1]; V _SacAnd V _SbcExpress for grid line voltage and below satisfying:

$\left\{\begin{array}{c}{V}_{\mathrm{Sac}}=V_{\mathrm{Sa}}-V_{\mathrm{Sc}}=U\sin \left(\mathrm{wt}\right)-U\sin (\mathrm{wt}-\frac{2\mathrm{\&pi;}}{3})=\sqrt{3}U\sin (\mathrm{wt}-\frac{\mathrm{\&pi;}}{6})\\ V_{\mathrm{Sbc}}=V_{\mathrm{Sb}}-V_{\mathrm{Sc}}=U\sin (\mathrm{wt}-\frac{2\mathrm{\&pi;}}{3})-U\sin (\mathrm{wt}+\frac{2\mathrm{\&pi;}}{3})=\sqrt{3}U\sin (\mathrm{wt}-\frac{\mathrm{\&pi;}}{2})\end{array}\right.---\left(11\right)$

According to formula (10) and formula (11), duty ratio d _aAnd d _bCan express as follows:

$\left\{\begin{array}{c}{d}_a=\frac{1}{u_{\mathrm{dc}}}{V}_{\mathrm{Sac}}-\frac{2L}{u_{\mathrm{dc}}}\frac{{\mathrm{di}}_{\mathrm{Sa}}}{\mathrm{dt}}-\frac{L}{u_{\mathrm{dc}}}\frac{{\mathrm{di}}_{\mathrm{Sb}}}{\mathrm{dt}}+\frac{1}{2}\\ d_b=\frac{1}{u_{\mathrm{dc}}}{V}_{\mathrm{Sbc}}-\frac{L}{u_{\mathrm{dc}}}\frac{{\mathrm{di}}_{\mathrm{Sa}}}{\mathrm{dt}}-\frac{2L}{u_{\mathrm{dc}}}\frac{{\mathrm{di}}_{\mathrm{Sb}}}{\mathrm{dt}}+\frac{1}{2}\end{array}\right.---\left(12\right)$

Follow the tracks of for the quick indifference that realizes electric current, adopt a kind of dead-beat control method, with formula (12) further discrete form represent:

$\left\{\begin{array}{c}{d}_a=\frac{1}{u_{\mathrm{dc}}}{V}_{\mathrm{Sac}}-\frac{2L}{u_{\mathrm{dc}}}\frac{i_{\mathrm{Sa}}-i_{\mathrm{ar}}}{T}-\frac{L}{u_{\mathrm{dc}}}\frac{i_{\mathrm{Sb}}-i_{\mathrm{br}}}{T}+\frac{1}{2}\\ d_b=\frac{1}{u_{\mathrm{dc}}}{V}_{\mathrm{Sbc}}-\frac{L}{u_{\mathrm{dc}}}\frac{i_{\mathrm{Sa}}-i_{\mathrm{ar}}}{T}-\frac{2L}{u_{\mathrm{dc}}}\frac{i_{\mathrm{Sb}}-i_{\mathrm{br}}}{T}+\frac{1}{2}\end{array}\right.---\left(13\right)$

Wherein, T is a control cycle.According to the principle and the control method of front, can make up the control block diagram of three-phase rectifier as shown in Figure 3.Rectifier to three-phase two arms; In order to realize the efficient high-quality of high frequency switch power supply system with ability, the present invention proposes a kind of dead-beat control method based on the bearing power feedforward, realize that the quick indifference of system is followed the tracks of; Improve the service behaviour of rectifier; Through the high-frequency PWM modulation system, realize the High Power Factor rectification of system, and reduce the electric current and voltage distortion of system.

Referring to Fig. 4, be the equivalent model of single high frequency DC/DC converter.Among the figure, E is a DC power supply; U is the output voltage of high frequency DC/DC converter; i _oOutput current for high frequency DC/DC converter; R _oInternal resistance for high frequency DC/DC converter; V _oAnd R _LBe respectively the voltage and the load of public connecting end.

According to circuit theory, following voltage-current relationship is arranged:

V _o=u-R _oi _o （14）

Can see that from following formula the fan-out capability of high frequency DC/DC converter receives the influence of its internal resistance, internal resistance is more little, and its fan-out capability is strong more.The internal resistance of different high frequency DC/DC converters is generally different, in the time will carrying out parallel connection to a plurality of high frequency DC/DC converters, adopt suitable current-sharing control method to realize the current-sharing operation of each high frequency DC/DC converter.To industries such as metallurgy, plating, it requires the electric current and voltage of power supply output is constant current-sharing, if deviation occurs, will have a strong impact on the quality of producing product, causes enormous economic loss.

Referring to Fig. 5, be the current/voltage double loop control of high frequency DC/DC converter.For the stable output of the constant pressure and flow of realizing high frequency DC/DC converter, the present invention invents and has proposed a kind of current/voltage double loop control, and concrete steps are following:

1) detects load DC side current i _o, testing result and set-point I _rSubtract each other,, obtain direct current outer shroud control output through PI controller and amplitude limit link

2) detect load dc voltage V _o, testing result and set-point

Subtract each other,, obtain voltage inter-loop control output, be the duty cycle signals d of half-bridge inverter through PI controller and amplitude limit link _o

3) through the high-frequency PWM modulation, obtain the control signal of single-phase semi-bridge inversion device switching device, driving switch is in control the output voltage current signal of expectation.

Steady-state behaviour for the output voltage electric current that improves high frequency switch power; The present invention proposes a kind of double loop control of current/voltage; Through the closed-loop adjustment of electric current outer shroud, realized that the stable state indifference of outer circular current is followed the tracks of, and obtained the reference signal of voltage inter-loop; Through the closed-loop control of voltage inter-loop, reach the purpose of the regulation voltage and the stabling current stream of system then.The control of current/voltage dicyclo guarantees that on the whole system's output current voltage is stable, improves the unfailing performance of device.

Claims (3)

1. large power, electrically electrolytic plating high frequency switch power; Comprise three-phase rectifier based on three-phase two arms, by the single-phase semi-bridge inversion device, the high frequency DC/DC converter that high-frequency coupling transformer and low pressure full-wave rectifier are composed in series; It is characterized in that; Said three-phase rectifier based on three-phase two arms is composed in parallel by two switch arms and DC side two series capacitance branch roads, and the single-phase semi-bridge inversion device is composed in parallel by a switch arm and DC side two series capacitance branch roads, both shared one group of dc bus capacitors; The input of three-phase rectifier links to each other with electrical network through three pole reactor L, and the output of three-phase rectifier links to each other with the single-phase semi-bridge inversion device.

2. the control method of the described large power, electrically electrolytic plating of claim 1 high frequency switch power is characterized in that, steps of the method are:

1) detects dc voltage u _DcWith set-point U _RefAfter subtracting each other, regulate pressure regulation command signal I of back output through the PI controller _OutSaid dc voltage u _DcBe DC side two series capacitance C ₁And C ₂The voltage sum;

2) detect DC side bearing power P _D, calculate the phase current magnitude of three-phase side according to principle of energy balance, be feedforward command signal I _S:

I _S=2P _D/3U

Wherein, U is the phase voltage amplitude of three-phase side;

3) the command signal I that will feedover _SWith pressure regulation command signal I _OutThe synchronizing signal of each phase is multiply by in stack then respectively, and the two phase switch arm current reference signals of trying to achieve based on the three-phase rectifier of three-phase two arms are:

4) detect DC side two capacitance voltage differences, obtain one after regulating through a PI controller and all press conditioning signal I _D, the total reference signal of circular current in this is all pressed conditioning signal directly to be added to constitute on the current reference signal:

5) according to the voltage-current relationship and the dead beat control principle of three-phase rectifier, try to achieve the duty cycle signals of two switch arms of three-phase rectifier, expression formula is following:

Wherein, T is a control cycle; L is the grid side outputting inductance; V _SacAnd V _SbcBe grid line voltage; i _SaAnd i _SbA, B two phase input currents for three-phase rectifier;

6) through the PWM modulator approach, according to duty ratio d _aAnd d _b, try to achieve the switching signal of two switch arm switching tubes of three-phase rectifier, the driving switch arm obtains the voltage and current signal of expectation.

3. the control method of large power, electrically electrolytic plating high frequency switch power according to claim 2 is characterized in that, the current/voltage double loop control of said high frequency DC/DC converter using may further comprise the steps:

1) detects load DC side current i _o, testing result and set-point I _rSubtract each other,, obtain direct current outer shroud control output through PI controller and amplitude limit link

2) detect load dc voltage V _o, testing result and set-point

Subtract each other,, obtain voltage inter-loop control output, be the duty cycle signals d of half-bridge inverter through PI controller and amplitude limit link _o

3) through the high-frequency PWM modulation, obtain the control signal of single-phase semi-bridge inversion device switching device, driving switch is in control the output voltage current signal of expectation.

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