CN102931819B - Power electronic converter control method based on transient electromagnetic energy balance - Google Patents

Abstract

The invention relates to a power electronic converter control method based on transient electromagnetic energy balance, belonging to the technical field of power electronics. The power electronic converter control method based on transient electromagnetic energy balance is characterized in that the control objects of a power electronic converter are converted into the transient electromagnetic energy, the control objects of different dimensions are unified through the electromagnetic energy, the transient electromagnetic energy is adjusted in the dynamic-state process to track the target steady energy quickly, and the electromagnetic energy is kept in the allowed change range of the dynamic-output target energy value in the steady-state process. The power electronic converter control method based on transient electromagnetic energy balance can be applied to various power electronic converters. The experimental result proves that compared with the conventional control method, the power electronic converter control method based on transient electromagnetic energy balance helps to increases the dynamic response speed, eliminate the control overshoot and improve system reliability while guaranteeing the steady-state control precision.

Description

Converters control method based on Transient Electromagnetic energy balance

Technical field

The control method that the present invention relates to Technics of Power Electronic Conversion system, belongs to electric and electronic technical field.

Background technology

The object of converter is to realize the efficient transformation of electromagnetic energy feature (electric weight waveform, characteristic parameter etc.).For obtaining desired conversion characteristics, in current most of converters, all adopt the method for PWM to obtain required electricity characteristic, this electromagnetic energy of exporting in PWM mode shows as pulse and pulse train form, and effectively pulse energy and sequence thereof are the citation forms in converters.This pulse energy is a kind of form of electromagnetic energy transient state conversion process, and its time constant is conventionally in microsecond or within nanosecond.The electromagnetic energy transient process of this short time yardstick plays a decisive role for the reliability service of converters: it is the basis of electric weight waveform transformation on the one hand; On the other hand, if control bad, it will directly cause component failure and device damage.

For the various classical control methods of converters, as vector control (VC), direct torque control (DTC), direct Power Control (DPC) etc., although ring (electric current loop or power ring) differs from one another in it, but common ground is its outer shroud has all adopted similar structure, by the error of command value (voltage or electric current) and value of feedback, adopt pi regulator to regulate, control structure figure is as shown in Fig. 1.

The PI controller (take DC master row voltage control as example) of this routine is as the formula (1):

$\left\{\begin{array}{c}u\left(k\right)=u(k-1)+k_i[V_{\mathrm{dc}}*\left(k\right)-V_{\mathrm{dc}}\left(k\right)]\\ p_{\mathrm{in}}(k+1)=k_p[V_{\mathrm{dc}}*\left(k\right)-V_{\mathrm{dc}}\left(k\right)]+u\left(k\right)\end{array}\right.---\left(1\right)$

It utilizes its integral element to eliminate departure.But integral element can cause overshoot to " memory effect " of past tense etching system state in dynamic process.Take DC bus-bar voltage uphill process as example, in voltage control dynamic process, actual DC busbar voltage departs from its command value, and the difference of command value and value of feedback is accumulation in time in PI controller integral element, and converter input active power or active current increase gradually.When input power rises to higher than power output and resistance consumption power sum, i.e. p _in> p _rs+ p _outtime, can obtain energy balance relations:

$E_{\mathrm{in}}-E_{\mathrm{Rs}}-E_{\mathrm{out}}={\mathrm{\ΔW}}_{\mathrm{EI}-1}+{\mathrm{\ΔW}}_{\mathrm{EI}-2}>0---\left(2\right)$

The input energy of " surplus " is poor by the inductance capacitance Power Flow in compensating converter and its steady-state target value, and the energy feature amount (DC bus-bar voltage and power network current) that energy-storage travelling wave tube is corresponding increases gradually.When energy storage in inductance capacitance reaches its target steady-state value, desirable converter input power should drop to p moment _in=p _rs*+p _out* make converter remain on target stable state (Δ W _eI-1=Δ W _eI-2=0) and then by DC bus-bar voltage remain on its command value.But due to the existence of PI controller integral element, make to input active power or active current command value slow decreasing gradually, also slow decreasing thereupon of the active power of actual input translator.In actual active power, drop to input active power value (p corresponding to target energy poised state _rs*+p _out*) before, wherein the input energy of " surplus " continues to make the energy storage of inductance capacitance to increase, and produces overshoot in DC bus-bar voltage.

Increase formula (2) is although middle PI controller integral element coefficient k i can accelerate the rate of climb of active power controlled quentity controlled variable in dynamic process, DC bus-bar voltage dynamic response is accelerated, but also can strengthen controller " memory effect ", DC bus-bar voltage overshoot is increased simultaneously; On the contrary, reduce k _ican effectively reduce DC bus-bar voltage overshoot, but can cause its dynamic response to slow down, and bearing power changes the DC bus-bar voltage causing and falls also and can increase, as shown in simulation waveform in Fig. 2.Therefore when the conventional voltage control strategy of application, there is the contradiction that is difficult to mediation in converters, between dynamic responding speed and overshoot.

As everyone knows, in the conversion process of electromagnetic energy, must follow electromagnetic energy conservation and the energy principle of can not suddenling change, this is the theoretical foundation of Transient Electromagnetic energy conversion.Transient Electromagnetic energy quantity research is in the past mainly at aspects such as electromagnetic compatibility and electronics time domain measuring technology and impulse radars.In field of power electronics application seldom, at aspects such as " PHYSICAL MECHANISM of semiconductor device failure " and " Transient field analysis of simple chopper circuit ", there are some preliminary application, but only limit to the electromagnetic field analysis in semiconductor switch device and simple topology.Calendar year 2001 Jan Abraham Ferreira and J. Dan Van Wyk have delivered the paper of the electromagnetic energy travels in one piece of converters, have represented from structure and the operation of the angle converters of energy, have enlightenment.But analysis and the control thereof of the Transient Electromagnetic of not touching upon energy balance process.

When having many group energy-storage travelling wave tubes in converters or having multiple control target of different nature (should control voltage, control again electric current), traditional voltage or current closed-loop control strategy are often difficult to accomplish to make overall plans.

Summary of the invention

The object of the invention is to adopt Transient Electromagnetic principle of energy balance to implement the multivariable Control of converter.Its control block diagram as shown in Figure 3.

The invention is characterized in, be to realize according to the following steps successively in a kind of pwm converter control system based on Transient Electromagnetic energy balance:

Step (1) builds the pwm converter control system based on Transient Electromagnetic energy balance described in;

Described pwm converter control system contains: pwm converter, transient energy counting circuit, transient state power output are calculated circuit, target stable state circuit for calculating energy, input power controlled quentity controlled variable counting circuit, direct Power Control switch list formation circuit, comparator and switching value control signal and formed circuit, wherein:

Transient energy counting circuit, is provided with: the first output voltage V _dc1with the second output voltage V _dc2input, V _dc1+ V _dc2=V _dc, a phase, b phase power supply instantaneous voltage e _a, e _btwo inputs, a phase, b phase power supply transient current i _a, i _btwo inputs, are also provided with: magnetic field energy W on inductive element in described pwm converter _eI-1electric field energy W on output and capacitive element _eI-2output, transient state three phases active power P _inoutput and transient state three phase reactive power q _inoutput,

Transient state power output is calculated circuit, is provided with: described i _a, i _b, P _in, W _eI-1, W _eI-2the input of each amount, is also provided with: transient state power output P _outoutput,

Target stable state circuit for calculating energy, is provided with: the output voltage target steady-state value of described pwm converter

input, described P _outthe input of value, is also provided with: two described W _eI-1and W _eI-2target steady-state value

with output,

Input power controlled quentity controlled variable counting circuit, is provided with: described each target steady-state quantity

, , each transient volume P _out, W _eI-1, W _eI-2input, be also provided with: described p _intarget steady-state quantity

, also claim input active power controlled quentity controlled variable

output,

Comparator, comprising: the first comparator Y _p, the second comparator Y _q, the 3rd comparator Y _n, wherein:

The first comparator Y _p, be power real component comparator, input is input active power controlled quentity controlled variable

, also have a described transient state active power p _in, output is

,

The second comparator Y _q, be power idle component comparator, input is Reactive Power Control amount

with described transient state reactive power q _in, output is

,

The 3rd comparator Y _n, be input as v _dc1and v _dc2, output is v _dc1-v _dc2,

Switching value control signal forms circuit, comprising: switching value control signal S _qformation circuit, switching value control signal S _pwith switching value control signal S _nformation circuit, wherein:

Switching value control signal S _pformation circuit, input is

, output is the switching value control signal S of active power control _p,

Switching value control signal S _qformation circuit, input is

, output is the switching value control signal S of Reactive Power Control _q,

Switching value control signal S _nformation circuit, input is v _cd1and v _cd2, output is v _cd1-v _cd2,

Described three switching value control signals form circuit and are a kind of stagnant ring comparison circuit,

Direct Power Control switch list is a kind of according to three switching value control signal S _p, S _qand S _nconverse and be sent to three switching value S of described pwm converter _a, S _band S _ccontrol vector matrix;

The described pwm converter control system based on Transient Electromagnetic energy balance of step (2) carries out controlling based on the PWM of Transient Electromagnetic energy balance successively according to the following steps:

The described transient energy counting circuit of step (2.1) is calculated as follows respectively W _eI-1, W _eI-2, p _inand q _in:

$W_{\mathrm{EI}-1}=\frac{1}{2}{L}_s{i_a}^2+\frac{1}{2}{L}_s{i_{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">b</figure-callout>}}}^2+\frac{1}{2}{L}_s{i_{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">c</figure-callout>}}}^2$

$W_{\mathrm{EI}-2}=\frac{1}{2}{C}_{\mathrm{dc}1}{{\mathrm{<figure-callout\; id="1"\; label="v\; dc"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\mathrm{dc}}}^2+\frac{1}{2}{C}_{\mathrm{dc}2}{{\mathrm{<figure-callout\; id="2"\; label="v\; dc"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\mathrm{dc}}}^2$

Wherein: L _sthe inductance of network reactor, C _dc1, C _dc2respectively the upper bus capacitor of DC bus and second edges generating line electric capacity of DC bus, i _ccan be according to three-phase circuit equilibrium principle, by i _a, i _bdetected value calculates,

$p_{\mathrm{in}}=e_{\mathrm{\&alpha;}}{i}_{\mathrm{\&alpha;}}=e_{\mathrm{\&beta;}}{i}_{\mathrm{\&beta;}}$

$q_{\mathrm{in}}=e_{\mathrm{\&beta;}}{i}_{\mathrm{\&alpha;}}-e_{\mathrm{\&alpha;}}{i}_{\mathrm{\&beta;}}$

Wherein: $\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{3}\end{array}\right]\left[\begin{array}{c}{e}_a\\ e_b\\ -e_a-e_b\end{array}\right]$ ， $\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{3}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ -i_a-i_b\end{array}\right]$ ，

The described transient state power output of step (2.2) is calculated circuit and is calculated as follows transient state power output P _out, by two continuous period T _scalculate Δ W _eI-1, Δ W _eI-2:

$P_{\mathrm{out}}=P_{\mathrm{in}}-P_{\mathrm{RS}}-\frac{{\mathrm{\&Delta;W}}_{\mathrm{EI}-1}-{\mathrm{\&Delta;W}}_{\mathrm{EI}-2}}{T_s}$

Wherein: P _rSthe loss of transient state equivalent resistance,

The described target stable state of step (2.3) circuit for calculating energy is calculated as follows

,

with steady-state equivalent resistance loss

:

$P_{\mathrm{RS}}^{*}=R_s{\left(\frac{\sqrt{3}E-\sqrt{3E^2-4R_s{P}_{\mathrm{out}}}}{2R_s}\right)}^2$

$W_{\underset{*}{E}I-1}^{*}=\frac{1}{2}{L}_s{\left(\frac{\sqrt{3}E-\sqrt{3E^2-4R_s{P}_{\mathrm{out}}}}{2R_s}\right)}^2$

$W_{\mathrm{EI}-2}^{*}=\frac{1}{8}({\mathrm{<figure-callout\; id="1"\; label="C\; dc"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{dc}}+C_{\mathrm{dc}2}){v_{\mathrm{dc}}^{*}}^2$

Wherein: R _sbe equivalent resistance, E is supply voltage effective value,

The described input power controlled quentity controlled variable of step (2.4) counting circuit is calculated as follows input active power controlled quentity controlled variable

with input Reactive Power Control amount :

$p_{\mathrm{in}}^{*}=\frac{E_{R_{s1}}^{*}}{T_s}+\frac{E_{R_{s2}}^{*}}{T_s}+...+\frac{E_{R_{\mathrm{sk}}}^{*}}{T_s}+P_{\mathrm{out}}$

Wherein: R _s1, R _s1... .. R _skrepresent k group equivalent resistance, k is limited positive integer, E _rkrepresent k group equivalent resistance R _kon voltage,

$q_{\mathrm{in}}^{*}=0$

Described the first comparator Y of step (2.5) _poutput

, described the second comparator Y _qoutput

, described the 3rd comparator Y _noutput v _dc1-v _dc2

The described switching value control signal of step (2.6) S _p, S _q, S _nby stagnant ring comparison circuit, determined respectively,

The described direct Power Control switch list of step (2.7) forms three switching value S of circuit output _a, S _b, S _c;

Step (3) judges continuous two period T _sΔ W _eI-1=Δ W _eI-2=0 is no, if Δ W _eI-1≠ Δ W _eI-2≠ 0, repeating step (2.1) is to step (2.7), until Δ W _eI-1=Δ W _eI-2=0, control and finish.

The present invention has advantages of following:

1, explicit physical meaning: in the control strategy based on transient energy balance, the derivation reference of governing equation is the transient energy balanced relationship in converter, loss and energy storage variable quantity in the input energy of the every respectively correspondent transform of this relational expression device, output energy, converter, have clear and definite physical significance.

2, unify different control objects: when the control strategy based on transient energy balance is applied in the Technics of Power Electronic Conversion system with multiple control objects, each electric current, voltage control object are converted to respectively to the Transient Electromagnetic energy of inductive element and capacitive element storage, and set up contact by energy balance relations, thereby can in control, unify to consider each control object.

3, control precision is high: because the governing equation based on transient energy balance control strategy is to be got by strict derivation of transient energy balanced relationship, the calculating of controlled quentity controlled variable has considered that all transient energy flow to, and therefore have higher control precision.

4, dynamic property is good: the target of the control strategy based on transient energy balance is within the shortest time, to make converter reach target energy stable state, in computational process, only relate to the system mode of current control cycle and a upper control cycle, " memory effect " of having avoided traditional control strategy, dynamic response is fast; In converter, each energy-storage travelling wave tube reaches after energy homeostasis simultaneously, and the control strategy based on transient energy balance regulates rapidly controlled quentity controlled variable, makes each energy-storage travelling wave tube remain on this stable state and energy exchange no longer occurs, and makes dynamic process substantially not produce overshoot.

Accompanying drawing explanation

Fig. 1. the conventional control method block diagram of converters;

(a) voltage oriented vector control (VOC) method block diagram

(b) direct Power Control (DPC) method block diagram

Fig. 2. traditional control strategy voltage control effect emulation waveform;

(a) increase integral coefficient

(b) reduce integral coefficient

Fig. 3. the pwm converter control block diagram based on Transient Electromagnetic energy balance

Fig. 4. Energy distribution and the flow direction in converter;

Fig. 5. the control method structured flowchart of three-level pwm converter based on transient energy balance

Fig. 6. three-level pwm converter DC bus-bar voltage command value sudden change simulation comparison waveform

(a) traditional control strategy

(b) control strategy based on transient energy balance

Fig. 7. three-level pwm converter bearing power sudden change simulation comparison waveform

(a) traditional control strategy

(b) control strategy based on transient energy balance

Fig. 8. three-level pwm converter bearing power mutating experiment contrast waveform

(a) traditional control strategy

(b) control strategy based on transient energy balance

Embodiment

According to law of conservation of energy, converters keeps energy balance any a period of time planted agent, inputs, the energy balance between output, loss and energy storage.With control cycle T of converters _sfor example, its Energy distribution and flow as shown in Figure 4.In a control cycle, the flow direction of input energy all can be divided into four parts: Part I is converted to the loss on each resistance (comprising equivalent resistance) in converter, Part II is converted to the magnetic field energy of storing in inductive element, Part III is converted to the electric field energy of storing in capacitive element, and Part IV outputs to the load of converter.Here the energy of inputting energy, export energy and flowing to energy-storage travelling wave tube can be two-way flow.

Suppose to have m group inductive element in converter, n group capacitive element and k group equivalent resistance, according to above-mentioned energy balance relations,

$E_{\mathrm{in}}={\mathrm{<figure-callout\; id="1"\; label="E\; R"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">E</figure-callout>}}_R+...+E_{\mathrm{Rk}}+{\mathrm{\&Delta;<figure-callout\; id="1"\; label="W\; L"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">W</figure-callout>}}_L+...+{\mathrm{\&Delta;W}}_{\mathrm{Lm}}+{\mathrm{\&Delta;<figure-callout\; id="1"\; label="W\; C"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">W</figure-callout>}}_C+...+{\mathrm{\&Delta;W}}_{\mathrm{Cn}}+E_{\mathrm{out}}---\left(3\right)$

Wherein, E _inand E _outrespectively the input and output energy in control cycle of converter, E _ri(i=1 ... k) be the energy of equivalent resistance at a control cycle internal loss, Δ W _li(i=1 ... m) be the variable quantity of transient magnetic field energy in a control cycle in inductive element, Δ W _ei(i=1 ... n) be the variable quantity of transient electric field energy in a control cycle in capacitive element.

The closed-loop control target of converters is generally voltage or the magnitude of current, and the each physical quantity in formula (3) can be set up corresponding relation with each voltage or the magnitude of current:

$E_{\mathrm{in}}={\&Integral;}_0^{T_s}{p}_{\mathrm{in}}\&CenterDot;\mathrm{dt}={\&Integral;}_0^{T_s}{u}_{\mathrm{in}}{i}_{\mathrm{in}}\&CenterDot;\mathrm{dt}---\left(4\right)$

$E_{\mathrm{out}}={\&Integral;}_0^{T_s}{p}_{\mathrm{out}}\&CenterDot;\mathrm{dt}={\&Integral;}_0^{T_s}{u}_{\mathrm{out}}{i}_{\mathrm{out}}\&CenterDot;\mathrm{dt}---\left(5\right)$

$\mathrm{dt}={\&Integral;}_0^{T_s}{u}_{\mathrm{Ri}}{i}_{\mathrm{Ri}}\&CenterDot;\mathrm{dt}={\&Integral;}_0^{T_s}{i_{\mathrm{<figure-callout\; id="2"\; label="Ri"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">Ri</figure-callout>}}}^2\&CenterDot;\mathrm{dt}={\&Integral;}_0^{T_s}\frac{{u_{\mathrm{Ri}}}^2}{R_i}\&CenterDot;\mathrm{dt}---\left(6\right)$

$W_{\mathrm{Li}}=\frac{1}{2}{L}_i{i_{\mathrm{Li}}}^2---\left(7\right)$

$W_{\mathrm{Ci}}=\frac{1}{2}{C}_i{u_{\mathrm{Ci}}}^2---\left(8\right)$

Above in each physical quantity, inductive current i _liwith capacitance voltage u _cisystem state variables, the general closed-loop control object as converter; Input voltage v _in, input current i _inor input power p _inthat Closed-loop Control Strategy need to go out the control variables in next cycle according to the control target of converter and current control cycle state computation, and then derives the on off state in next cycle by changing directly controlled control variables of on off state.Target based on transient energy balance control strategy is to make converter with a prestissimo (control cycle T _sin) reach and remain on stable state, therefore draw its governing equation:

$p_{\mathrm{in}}=\frac{{{\mathrm{<figure-callout\; id="1"\; label="E\; R"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">E</figure-callout>}}_R}^{*}}{T_s}+...+\frac{{E_{\mathrm{Rk}}}^{*}}{T_s}+\frac{{{\mathrm{<figure-callout\; id="1"\; label="W\; L"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">W</figure-callout>}}_L}^{*}-W_{L1}}{T_s}+...+\frac{{W_{\mathrm{Lm}}}^{*}-W_{\mathrm{Lm}}}{T_s}+\frac{{{\mathrm{<figure-callout\; id="1"\; label="W\; C"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">W</figure-callout>}}_C}^{*}-W_{C1}}{T_s}+...+\frac{{W_{\mathrm{Cn}}}^{*}-W_{\mathrm{Cn}}}{T_s}+p_{\mathrm{out}}---\left(9\right)$

Equal sign right side is the representative actual value with subscript variable not, can obtain by sensor feedback value; With the representative desired value (steady-state value) of asterisk subscript variable, wherein part is known convertor controls target, and another part needs to calculate by the target stable state energy balance relations of converter.

When converter reaches target stable state, the Transient Electromagnetic energy of storing in each energy-storage travelling wave tube in converter no longer changes, and in a control cycle, input energy and resistance loss and output energy reach balance, therefore, ${p_{\mathrm{in}}}^{*}=\frac{{{\mathrm{<figure-callout\; id="1"\; label="E\; R"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">E</figure-callout>}}_R}^{*}}{T_s}+...+\frac{{E_{\mathrm{Rk}}}^{*}}{T_s}+p_{\mathrm{out}}---\left(10\right)$

According to this energy balance relations formula, can calculate the unknown object value in formula (7), further can calculate the needed input control amount of next control cycle converter, finally according to inverter main circuit, obtain the switch controlling signal in next cycle.

With the transient energy control balancing in three-level pwm converter, be made as example.

According to formula (9), the transient energy balance governing equation in three-level pwm converter is:

$p_{\mathrm{in}}={p_{\mathrm{Rs}}}^{*}+\frac{{W_{\mathrm{EI}-1}}^{*}-W_{\mathrm{EI}-1}+{W_{\mathrm{EI}-2}}^{*}-W_{\mathrm{EI}-2}}{T_s}+p_{\mathrm{out}}---\left(11\right)$

Wherein, the transient energy WEI-1 of network reactor and the current storage of bus capacitor and WEI-2 can calculate by sensor sample value:

$\begin{array}{c}{W}_{\mathrm{EI}-1}=\frac{1}{2}{L}_s{i_a}^2+\frac{1}{2}{L}_s{i_{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">b</figure-callout>}}}^2+\frac{1}{2}{L}_s{i_c}^2\\ =\frac{1}{2}{L}_s{i_{\mathrm{\&alpha;}}}^2+\frac{1}{2}{L}_s{i_{\mathrm{\&beta;}}}^2\end{array}---\left(12\right)$

$W_{\mathrm{EI}-2}=\frac{1}{2}{C}_{\mathrm{dc}1}{{\mathrm{<figure-callout\; id="1"\; label="V\; dc"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{dc}}}^2+\frac{1}{2}{C}_{\mathrm{dc}2}{{\mathrm{<figure-callout\; id="2"\; label="V\; dc"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{dc}}}^2---\left(13\right)$

Bus capacitor target stable state energy WEI-2* can directly calculate according to DC bus-bar voltage command value:

$\begin{array}{c}{W_{\mathrm{EI}-2}}^{*}=\frac{1}{2}{C}_{\mathrm{de}1}{{\mathrm{<figure-callout\; id="1"\; label="V\; dc"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{dc}}^1}^2+\frac{1}{2}{C}_{\mathrm{dc}2}{{\mathrm{<figure-callout\; id="2"\; label="V\; dc"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{dc}}^2}^2\\ =\frac{1}{8}({\mathrm{<figure-callout\; id="1"\; label="C\; dc"\; filenames="HDA00002443681900031.png"\; state="\{\{state\}\}">C</figure-callout>}}_{\mathrm{dc}}+C_{\mathrm{dc}2}){V_{\mathrm{dc}}^{*}}^2\end{array}---\left(14\right)$

Power output pout can be calculated by continuous two periodic sampling values:

$p_{\mathrm{out}}=p_{\mathrm{in}}-p_{\mathrm{Rs}}-\frac{{\mathrm{\&Delta;W}}_{\mathrm{EI}-1}+{\mathrm{\&Delta;W}}_{\mathrm{EI}-2}}{T_s}---\left(15\right)$

Steady-state equivalent resistance loss p _rs ^*with network reactor target stable state energy W _eI-1 ^*need to derive according to target stable state energy balance relations (10):

$\begin{array}{c}{p_{\mathrm{Rs}}}^{*}=R_s(i_{\mathrm{\&alpha;}}^{*2}+i_{\mathrm{\&beta;}}^{*2})\\ =R_s{\left(\frac{\sqrt{3}E-\sqrt{{3E}^2-4R_s{p}_{\mathrm{out}}}}{2R_s}\right)}^2\end{array}---\left(16\right)$

$\begin{array}{c}{W_{\mathrm{EI}-1}}^{*}=\frac{1}{2}{L}_s{i}_{\mathrm{\&alpha;}}^{*2}+\frac{1}{2}{L}_s{i}_{\mathrm{\&beta;}}^{*2}\\ =\frac{1}{2}{L}_s{\left(\frac{\sqrt{3}E-\sqrt{{3E}^2-4R_s{p}_{\mathrm{out}}}}{2R_s}\right)}^2\end{array}---\left(17\right)$

According to above-mentioned input active power controlled quentity controlled variable calculation procedure, build the control strategy structured flowchart of three-level pwm converter based on transient energy balance as shown in Figure 5.

Fig. 6 is three-level pwm converter tradition control strategy and DC bus-bar voltage and meritorious, the reactive power simulation comparison waveform of the control strategy based on transient energy balance when DC bus-bar voltage command value is suddenlyd change.Can find out, with respect to traditional control strategy, to the adjusting of power more rapidly and accurately, the dynamic responding speed of DC bus-bar voltage is faster, and has overshoot hardly for the control strategy based on transient energy balance.

Fig. 7 and Fig. 8 are respectively three-level pwm converter tradition control strategy and simulation comparison waveform and the experiment contrast waveform of the control strategy based on transient energy balance when bearing power is suddenlyd change.Can find out that after the control strategy adopting based on transient energy balance, active power control is rapider, DC bus-bar voltage is fallen less, and recovers sooner.From experimental result, can draw, adopt after control strategy based on transient energy balance, DC bus-bar voltage is fallen amplitude and is dropped to originally below 1/3, has effectively improved the stability of DC bus-bar voltage.

Claims (1)

1. the converters control method based on Transient Electromagnetic energy balance, is characterized in that, is to realize according to the following steps successively in a kind of pwm converter control system based on Transient Electromagnetic energy balance:

Step (1) builds the pwm converter control system based on Transient Electromagnetic energy balance described in;

Described pwm converter control system contains: pwm converter, transient energy counting circuit, transient state power output are calculated circuit, target stable state circuit for calculating energy, input power controlled quentity controlled variable counting circuit, direct Power Control switch list formation circuit, comparator and switching value control signal and formed circuit, wherein:

Transient energy counting circuit, is provided with: the first output voltage V _dc1with the second output voltage V _dc2input, V _dc1+ V _dc2=V _dc, a phase, b phase power supply instantaneous voltage e _a, e _btwo inputs, a phase, b phase power supply transient current i _a, i _btwo inputs, are also provided with: magnetic field energy W on inductive element in described pwm converter _eI-1electric field energy W on output and capacitive element _eI-2output, transient state three phases active power P _inoutput and transient state three phase reactive power q _inoutput,

Transient state power output is calculated circuit, is provided with: described i _a, i _b, P _in, W _eI-1, W _eI-2the input of each amount, is also provided with: transient state power output P _outoutput,

Target stable state circuit for calculating energy, is provided with: the output voltage target steady-state value of described pwm converter

input, described P _outthe input of value, is also provided with: two described W _eI-1and W _eI-2target steady-state value

with

output,

Input power controlled quentity controlled variable counting circuit, is provided with: described each target steady-state quantity ,

, each transient volume P _out, W _eI-1, W _eI-2input, be also provided with: described p _intarget steady-state quantity

, also claim input active power controlled quentity controlled variable output,

Comparator, comprising: the first comparator Y _p, the second comparator Y _q, the 3rd comparator Y _n, wherein:

The first comparator Y _p, be power real component comparator, input is input active power controlled quentity controlled variable

, also have a described transient state active power p _in, output is

,

The second comparator Y _q, be power idle component comparator, input is Reactive Power Control amount

with described transient state reactive power q _in, output is

,

The 3rd comparator Y _n, be input as v _dc1and v _dc2, output is v _dc1-v _dc2,

Switching value control signal forms circuit, comprising: switching value control signal S _qformation circuit, switching value control signal S _pwith switching value control signal S _nformation circuit, wherein:

Switching value control signal S _pformation circuit, input is

, output is the switching value control signal S of active power control _p,

Switching value control signal S _qformation circuit, input is

, output is the switching value control signal S of Reactive Power Control _q,

Switching value control signal S _nformation circuit, input is v _cd1and v _cd2, output is v _cd1-v _cd2,

Described three switching value control signals form circuit and are a kind of stagnant ring comparison circuit,

Direct Power Control switch list is a kind of according to three switching value control signal S _p, S _qand S _nconverse and be sent to three switching value S of described pwm converter _a, S _band S _ccontrol vector matrix;

The described pwm converter control system based on Transient Electromagnetic energy balance of step (2) carries out controlling based on the PWM of Transient Electromagnetic energy balance successively according to the following steps:

The described transient energy counting circuit of step (2.1) is calculated as follows respectively W _eI-1, W _eI-2, p _inand q _in:

$W_{\mathrm{EI}-1}=\frac{1}{2}{L}_s{i_a}^2+\frac{1}{2}{L}_s{i_b}^2+\frac{1}{2}{L}_s{i_c}^2$

$W_{\mathrm{EI}-2}=\frac{1}{2}{C}_{\mathrm{dc}1}{v_{\mathrm{dc}1}}^2+\frac{1}{2}{C}_{\mathrm{dc}2}{v_{\mathrm{dc}2}}^2$

Wherein: L _sthe inductance of network reactor, C _dc1, C _dc2respectively the upper bus capacitor of DC bus and second edges generating line electric capacity of DC bus, i _ccan be according to three-phase circuit equilibrium principle, by i _a, i _bdetected value calculates,

$p_{\mathrm{in}}=e_{\mathrm{\&alpha;}}{i}_{\mathrm{\&alpha;}}=e_{\mathrm{\&beta;}}{i}_{\mathrm{\&beta;}}$

$q_{\mathrm{in}}=e_{\mathrm{\&beta;}}{i}_{\mathrm{\&alpha;}}-e_{\mathrm{\&alpha;}}{i}_{\mathrm{\&beta;}}$

Wherein: $\left[\begin{array}{c}{e}_{\mathrm{\&alpha;}}\\ e_{\mathrm{\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{3}\end{array}\right]\left[\begin{array}{c}{e}_a\\ e_b\\ -e_a-e_b\end{array}\right]$ ， $\left[\begin{array}{c}{i}_{\mathrm{\&alpha;}}\\ i_{\mathrm{\&beta;}}\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{ccc}1& -\frac{1}{2}& -\frac{1}{2}\\ 0& \frac{\sqrt{3}}{2}& -\frac{\sqrt{3}}{3}\end{array}\right]\left[\begin{array}{c}{i}_a\\ i_b\\ -i_a-i_b\end{array}\right]$ ，

The described transient state power output of step (2.2) is calculated circuit and is calculated as follows transient state power output P _out, by two continuous period T _scalculate Δ W _eI-1, Δ W _eI-2:

$P_{\mathrm{out}}=P_{\mathrm{in}}-P_{\mathrm{RS}}-\frac{{\mathrm{\&Delta;W}}_{\mathrm{EI}-1}-{\mathrm{\&Delta;W}}_{\mathrm{EI}-2}}{T_s}$

Wherein: P _rSthe loss of transient state equivalent resistance,

The described target stable state of step (2.3) circuit for calculating energy is calculated as follows ,

with steady-state equivalent resistance loss

:

$P_{\mathrm{RS}}^{*}=R_s{\left(\frac{\sqrt{3}E-\sqrt{3E^2-4R_s{P}_{\mathrm{out}}}}{2R_s}\right)}^2$

$W_{\underset{*}{E}I-1}^{*}=\frac{1}{2}{L}_s{\left(\frac{\sqrt{3}E-\sqrt{3E^2-4R_s{P}_{\mathrm{out}}}}{2R_s}\right)}^2$

$W_{\mathrm{EI}-2}^{*}=\frac{1}{8}(C_{\mathrm{dc}1}+C_{\mathrm{dc}2}){v_{\mathrm{dc}}^{*}}^2$

Wherein: R _sbe equivalent resistance, E is supply voltage effective value,

The described input power controlled quentity controlled variable of step (2.4) counting circuit is calculated as follows input active power controlled quentity controlled variable with input Reactive Power Control amount :

$p_{\mathrm{in}}^{*}=\frac{E_{R_{s1}}^{*}}{T_s}+\frac{E_{R_{s2}}^{*}}{T_s}+...+\frac{E_{R_{\mathrm{sk}}}^{*}}{T_s}+P_{\mathrm{out}}$

Wherein: R _s1, R _s1... .. R _skrepresent k group equivalent resistance, k is limited positive integer, E _rkrepresent k group equivalent resistance R _kon voltage,

$q_{\mathrm{in}}^{*}=0$

Described the first comparator Y of step (2.5) _poutput

, described the second comparator Y _qoutput-q _in, described the 3rd comparator Y _noutput v _dc1-v _dc2

The described switching value control signal of step (2.6) S _p, S _q, S _nby stagnant ring comparison circuit, determined respectively,

The described direct Power Control switch list of step (2.7) forms three switching value S of circuit output _a, S _b, S _c;

Step (3) judges continuous two period T _sΔ W _eI-1=Δ W _eI-2=0 is no, if Δ W _eI-1≠ Δ W _eI-2≠ 0, repeating step (2.1) is to step (2.7), until Δ W _eI-1=Δ W _eI-2=0, control and finish.

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