CN104377725B - A kind of no phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm - Google Patents

Abstract

The invention discloses a kind of no phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm, realize under synchronous rotating frame, without phaselocked loop, clap according to control system actual time delay two, clap power output and the impact of current forecasting precision for reducing next and simplify prediction calculating, use the sample frequency doubling carrier frequency, need not complicated calculations, just can accurately be calculated next grid-connected power clapped, grid-connected current and line voltage value, improve control accuracy, then the output of next carrier cycle three-phase convertor circuit it is calculated, the carried control method of the present invention is simple, can realize 3-phase power converter determines the prediction of frequency no phase-locked loop Direct Power, it is prone to through engineering approaches.

Description

A kind of no phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm

Technical field

The present invention relates to a kind of no phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm, belong to electric and electronic technical field.

Background technology

Three-phase DC/AC current transformer have be capable of alternating current-direct current bi-directional power flow, power factor is adjustable, grid-connected current sine degree high, Fast development recently as distributed power generation has obtained studying widely and applying, and its performance directly influences the quality of power supply of distributed power generation. In numerous control methods, direct Power Control (direct power control, DPC) has that control algolithm is simple, power factor can be in harmonious proportion well The advantage of dynamic property.DPC comes from the Direct Torque Control (Direct torque control, DTC) of motor, and DTC need not carry out electric current Control, selected voltage vector according to sector and demand by switch list, it is achieved motor torque and the directly control of magnetic linkage.According to same principle, will DPC is applied in 3-phase power converter, can realize the meritorious instantaneous power control with reactive power of three-phase grid-connected converter.

DPC is to realize power control by Hysteresis control, and this causes the change of running breaker in middle frequency, to power circuit and design of Cooling System Bring the biggest difficulty, and broadband is unfavorable for the design of grid-connected wave filter, thus reduce the output quality of power supply of grid-connected converter.For asking above Topic, it is proposed that use fixed switching frequency DPC scheme.But tradition fixed frequency direct Power Control (constant frequence DPC, CF-DPC) is passed through Closed-loop control obtains current transformer output voltage, and this needs to adjust closed loop control parameters to obtain good dynamic and static state performance, and digital control Time delay also affect the performance of system.For digital control delay, control the difficult problems such as parameter tuning, for improving control performance further, it was predicted that control Technology is introduced in CF-DPC, and Direct Power PREDICTIVE CONTROL (predictive DPC, P-DPC) is the indifference realizing grid-connected power based on Mathematical Modeling Clap optimal control.Traditional PREDICTIVE CONTROL is open-loop prediction, claps time delay for one and is predicted controlling, have ignored and include having little time to update dutycycle Present sample controls the cycle and the time delay in the next control cycle worked, and next claps output quantity to be difficult to accurately prediction, and then affects control accuracy.

DPC uses space vector pulse width modulation (space vector pulse width modulation, SVPWM) to realize, and needs to carry out line voltage Phase-locked to obtain mains frequency and phase angle, which increase control difficulty and the operand of control system, reduce efficiency." two-way three-phase AC/DC The no phase-locked loop control strategy of current transformer. Proceedings of the CSEE, 2013,33 (36): 79-87 " propose two-way three-phase AC/DC current transformer No phase-locked loop control strategy, but still need to regulate by increasing reactive power closed loop, given frequency adjusted in real time, solve frequency given and The control error that electrical network actual frequency does not also results in." Hardware delay compensation of no phase-locked loop Synchronous Reference Frame Transform detection method. China's electrical engineering Report, 2008,28 (27): 78-83 " propose no phase-locked loop Synchronous Reference Frame Transform detection method, still need to introduce phase place in synchronous coordinate inverse-transform matrix Compensate angle hardware time delay is compensated.

Summary of the invention

It is an object of the invention to overcome deficiency of the prior art, it is provided that a kind of no phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm, should Method realizes under synchronous rotating frame, it is not necessary to electrical network carries out phase lock control, and realizes direct to grid-connected power dead beat by PREDICTIVE CONTROL Control.

For reaching above-mentioned purpose, the technical solution adopted in the present invention is: a kind of no phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm, bag Include following steps:

Step one: in (k-1) T, (k-1/2) T, kT, (k+1/2) T, (k+1) T, (k+3/2) T, (k+2) T moment, respectively to three-phase power grid voltage e_a、 e_b、e_cWith three-phase grid electric current i_a、i_b、i_cSampling, T is a triangular carrier cycle of PWM, and k is integer；

Step 2: three-phase power grid voltage step one sampling obtained and three-phase grid electric current convert through Clark conversion and Park respectively, are synchronized Three-phase power grid voltage vector e under rotating coordinate system_d、e_qWith three-phase grid current vector i_d、i_q；

Step 3: according to instantaneous power theory, calculates instantaneous active power P and reactive power Q:

$\left[\begin{array}{c}P\\ Q\end{array}\right]=\frac{3}{2}\left[\begin{array}{cc}{e}_d& e_q\\ e_q& -e_d\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]$

Step 4: according to the active-power P in (k+1/2) T moment^mid(k) and reactive power Q^mid(k), the active-power P (k) in kT moment and reactive power Q (k), calculates (k+1) T moment active power predicted value P₁And reactive power predicted value Q (k+1)₁(k+1):

$\left[\begin{array}{c}{P}_1(k+1)\\ Q_1(k+1)\end{array}\right]=2\left[\begin{array}{c}{P}^{mid}\left(k\right)\\ Q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}P\left(k\right)\\ Q\left(k\right)\end{array}\right]$

Step 5: according to the grid-connected current in (k+1/2) T momentWithGrid-connected current i in kT moment_d(k) and i_qK (), calculates (k+1) T Grid-connected current predicted value i in moment_d1And i (k+1)_q1(k+1):

$\left[\begin{array}{c}{i}_{d1}(k+1)\\ i_{q1}(k+1)\end{array}\right]=2\left[\begin{array}{c}{i}_d^{mid}\left(k\right)\\ i_q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}{i}_d\left(k\right)\\ i_q\left(k\right)\end{array}\right]$

Step 6: be according to the line voltage in (k+1/2) T momentWithThe line voltage in kT moment is e_d(k) and e_q(k), meter Calculate line voltage predicted value e in (k+1) T moment_d1And e (k+1)_q1(k+1):

$\left[\begin{array}{c}{e}_{d1}(k+1)\\ e_{q1}(k+1)\end{array}\right]=2\left[\begin{array}{c}{e}_d^{mid}\left(k\right)\\ e_q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}{e}_d\left(k\right)\\ e_q\left(k\right)\end{array}\right]$

Step 7: calculate (k+1) T to (k+2) T moment current transformer output voltage vector v_dAnd v (k+1)_q(k+1):

$\left\{\begin{array}{c}{v}_d(k+1)=\frac{2L}{\[e_{d1}^2(k+1)+e_{q1}^2(k+1)\]3T}\left\{e_{d1}\right(k+1)\\ \[P_{ref}(k+2)-P_1(k+1)\]+e_{q1}(k+1)\[Q_{ref}(k+2)\\ -Q_1(k+1)\]\}+e_{d1}(k+1)-{\mathrm{\ω}}_{1}L{i}_{q1}(k+1)\\ v_q(k+1)=\frac{2L}{\[e_{d1}^2(k+1)+e_{q1}^2(k+1)\]3T}\left\{e_{q1}\right(k+1)\\ \[P_{ref}(k+2)-P_1(k+1)\]-e_{d1}(k+1)\[Q_{ref}(k+2)\\ -Q_1(k+1)\]\}+e_{q1}(k+1)+{\mathrm{\ω}}_{1}L{i}_{d1}(k+1)\end{array}\right.$

Wherein: P_ref(k+2) it is (k+2) T moment grid-connected active power reference value；Q_ref(k+2) it is (k+2) T moment grid-connected reactive power reference qref； L is three-phase grid inductance value；ω₁=2 π f₁t；f₁For controlling the frequency set；

Step 8: by current transformer output voltage vector v_dAnd v (k+1)_q(k+1) through Park inverse transformation, SVPWM modulation, current transformer power tube is exported Drive signal.

When step 2 carries out Park conversion, synchronous rotating frame and the angle theta=θ of rest frame₁+2πf₁T, t are the moment, phase angle theta₁For appointing Meaning value.

Compared with prior art, the present invention is reached to provide the benefit that: clap according to control system actual time delay two, claps power output for reducing next Impact and simplification prediction with current forecasting precision calculate, and use the sample frequency doubling carrier frequency, it is not necessary to complicated calculations, just can accurately count Calculate the predicted value obtaining next grid-connected power, grid-connected current and line voltage clapped, improve control accuracy, be then calculated next carrier cycle The output of phase three-phase convertor circuit.Without phaselocked loop, f₁With f₀The performance of deviation control method carried on the present invention do not affect, it is not necessary to for frequency The regulation of rate deviation, decreases the impact on control performance of the phase-locked error.Control method provided by the present invention is simple, can realize three-phase unsteady flow Device determine frequency no phase-locked loop Direct Power PREDICTIVE CONTROL, it is easy to through engineering approaches.

Accompanying drawing explanation

Fig. 1 is the 3-phase power converter system construction drawing using the present invention.

Fig. 2 is 3-phase power converter output voltage effect sequential chart.

Fig. 3 is the algorithm principle block diagram of the present invention.

Fig. 4 is given active power 20kW and reactive power 20kVAR, changes f₁The simulation waveform obtained.

Detailed description of the invention

The invention will be further described below in conjunction with the accompanying drawings.Following example are only used for clearly illustrating technical scheme, and can not Limit the scope of the invention with this.

As it is shown in figure 1,3-phase power converter includes dc source U_dc, six IGBT power tubes, three-phase reactor L and dc-link capacitance C, six Individual IGBT power tube composition three phase bridge circuit, dc-link capacitance C is connected in parallel on dc source U_dcTwo ends, three-phase reactor be series at current transformer and Between three phase network, control system, according to the calculated output being worth to three phase bridge circuit of sampling, obtains driving signal to drive by SVPWM Each IGBT switchs, and controls grid-connected power and reaches setting value.

As it is shown on figure 3, no phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm, comprise the following steps:

Step one: in Fig. 2, in (k-1) T, (k-1/2) T, kT, (k+1/2) T, (k+1) T, (k+3/2) T, (k+2) T moment, respectively to three-phase electricity Net voltage e_a、e_b、e_cWith three-phase grid electric current i_a、i_b、i_cSampling, T is a triangular carrier cycle of PWM, and k is integer.

Step 2: three-phase power grid voltage step one sampling obtained and three-phase grid electric current convert (in Fig. 1 through Clark conversion and Park respectively Dp conversion i.e. Clark conversion and Park convert), obtain the three-phase power grid voltage vector e under synchronous rotating frame_d、e_qWith three-phase grid electric current to Amount i_d、i_q；

Ignoring line impedance, three phase network is symmetrical, and the current transformer Mathematical Modeling under three-phase static coordinate system is:

$L\frac{d}{dt}\left[\begin{array}{c}{i}_a\\ i_b\\ i_c\end{array}\right]=\left[\begin{array}{c}{v}_{an}\\ v_{bn}\\ v_{cn}\end{array}\right]-\left[\begin{array}{c}{e}_a\\ e_b\\ e_c\end{array}\right]---\left(1\right)$

In formula, v_an、v_bn、v_cnFor 3-phase power converter half-bridge output a, b, c relative to the output voltage of neutral point of electric network, i_a、i_b、i_cFor three-phase grid electricity Stream.

Formula (1) converts through Clarke, can obtain the current transformer Mathematical Modeling under static α β coordinate system:

$L\frac{d}{dt}\left[\begin{array}{c}{I}_{\mathrm{\α}\mathrm{\β}}sin({\mathrm{\ω}}_{0}t+\mathrm{\ζ})\\ I_{\mathrm{\α}\mathrm{\β}}\sin ({\mathrm{\ω}}_{0}t-\mathrm{\π}/2+\mathrm{\ζ})\end{array}\right]=\left[\begin{array}{c}{v}_{\mathrm{\α}}\\ v_{\mathrm{\β}}\end{array}\right]-\left[\begin{array}{c}{E}_{\mathrm{\α}\mathrm{\β}}sin({\mathrm{\ω}}_{0}t+\mathrm{\ψ})\\ E_{\mathrm{\α}\mathrm{\β}}\sin ({\mathrm{\ω}}_{0}t-\mathrm{\π}/2+\mathrm{\ψ})\end{array}\right]---\left(2\right)$

In formula, I_αβAnd E_αβIt is respectively the grid-connected current under static α β coordinate system and the peak value of line voltage, v_αβ=[v_α,v_β]^TFor becoming under static α β coordinate system Stream device bridge output voltage, ω₀=2 π f₀For actual electric network angular frequency, ψ and ζ is respectively the phase angle of line voltage and grid-connected current.

Two-phase static α β coordinate is tied to the Park of two-phase synchronous rotating frame and is transformed to:

$\left[\begin{array}{c}{e}_d\\ e_q\end{array}\right]=\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{c}{E}_{\mathrm{\α}\mathrm{\β}}\sin ({\mathrm{\ω}}_{0}t+\mathrm{\ψ})\\ E_{\mathrm{\α}\mathrm{\β}}\sin ({\mathrm{\ω}}_{0}t-\mathrm{\π}/2+\mathrm{\ψ})\end{array}\right]=\left[\begin{array}{c}{E}_{\mathrm{\α}\mathrm{\β}}\sin ({\mathrm{\ω}}_{0}t+\mathrm{\ψ}-{\mathrm{\ω}}_{1}t-{\mathrm{\θ}}_1)\\ -E_{\mathrm{\α}\mathrm{\β}}\cos ({\mathrm{\ω}}_{0}t+\mathrm{\ψ}-{\mathrm{\ω}}_{1}t-{\mathrm{\θ}}_1)\end{array}\right]---\left(3\right)$

$\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\left[\begin{array}{cc}\cos \mathrm{\θ}& \sin \mathrm{\θ}\\ -\sin \mathrm{\θ}& \cos \mathrm{\θ}\end{array}\right]\left[\begin{array}{c}{I}_{\mathrm{\α}\mathrm{\β}}\sin ({\mathrm{\ω}}_{0}t+\mathrm{\ζ})\\ I_{\mathrm{\α}\mathrm{\β}}\sin ({\mathrm{\ω}}_{0}t-\mathrm{\π}/2+\mathrm{\ζ})\end{array}\right]=\left[\begin{array}{c}{I}_{\mathrm{\α}\mathrm{\β}}\sin ({\mathrm{\ω}}_{0}t+\mathrm{\ζ}-{\mathrm{\ω}}_{1}t-{\mathrm{\θ}}_1)\\ -I_{\mathrm{\α}\mathrm{\β}}\cos ({\mathrm{\ω}}_{0}t+\mathrm{\ζ}-{\mathrm{\ω}}_{1}t-{\mathrm{\θ}}_1)\end{array}\right]---\left(4\right)$

In formula, i_dq=[i_d,i_q]^TAnd e_dq=[e_d,e_q]^TBeing respectively the grid-connected current under synchronous rotating frame and line voltage, θ is synchronous rotating frame and two The angle of phase rest frame.θ=θ₁+2πf₁T, f₁The frequency set for control system, phase angle theta₁Can be arbitrary value, it is not necessary to carry out phase lock control.

Formula (2), through Park coordinate transform, can the current transformer Mathematical Modeling under synchronous rotating frame be represented by:

$L\frac{d}{dt}\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]=\left[\begin{array}{c}{v}_d\\ v_q\end{array}\right]-\left[\begin{array}{c}{e}_d-{\mathrm{\ω}}_1{\mathrm{Li}}_q\\ e_q+{\mathrm{\ω}}_1{\mathrm{Li}}_d\end{array}\right]---\left(5\right)$

In formula, v_dq=[v_d,v_q]^TFor the three-phase bridge output voltage under synchronous rotating frame.

Step 3: according to instantaneous power theory, the instantaneous active power P and the reactive power Q that calculate 3-phase power converter output be:

$\left[\begin{array}{c}P\\ Q\end{array}\right]=\frac{3}{2}\left[\begin{array}{cc}{e}_d& e_q\\ e_q& -e_d\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]---\left(6\right)$

Formula (5) discretization is obtained:

$\left[\begin{array}{c}{i}_d(k+1)-i_d\left(k\right)\\ i_q(k+1)-i_q\left(k\right)\end{array}\right]=\frac{T}{L}\left(\left[\begin{array}{c}{v}_d\left(k\right)+{\mathrm{\ω}}_1{\mathrm{Li}}_q\left(k\right)\\ v_q\left(k\right)-{\mathrm{\ω}}_1{\mathrm{Li}}_d\left(k\right)\end{array}\right]-\left[\begin{array}{c}{e}_d\left(k\right)\\ e_q\left(k\right)\end{array}\right]\right)---\left(7\right)$

By formula (6) discretization, and formula (7) is substituted into:

$\left[\begin{array}{c}P(k+1)-P\left(k\right)\\ Q(k+1)-Q\left(k\right)\end{array}\right]=\frac{3T}{2L}\left[\begin{array}{cc}{e}_d\left(k\right)& e_q\left(k\right)\\ e_q\left(k\right)& -e_d\left(k\right)\end{array}\right]\left(\left[\begin{array}{c}{v}_d\left(k\right)+{\mathrm{\ω}}_1{\mathrm{Li}}_q\left(k\right)\\ v_q\left(k\right)-{\mathrm{\ω}}_1{\mathrm{Li}}_d\left(k\right)\end{array}\right]-\left[\begin{array}{c}{e}_d\left(k\right)\\ e_q\left(k\right)\end{array}\right]\right)---\left(8\right)$

In actual numerical control system, due to links such as AD sampling, signal filtering and control algolithm calculating, from sampling of voltage x current value The generation of output voltage signal, is constantly present inevitable digital delay.Current transformer output voltage effect sequential as in figure 2 it is shown, the kT moment to change The stream grid-connected current of device, DC bus-bar voltage and line voltage are sampled, when the control computing of kT～(k+1) T time section obtains (k+1) T～(k+2) T Between section three-phase bridge output v_dAnd v (k+1)_q(k+1), the quantity of state of system reaches desired value in (k+2) T moment, and whole time delay reaches 2T.In order to Realize the accurate control to (k+2) T moment output valve, it was predicted that control to need the current transformer quantity of state in (k+1) T moment is precalculated.

The active power of the active power of step 4: kT to (k+1/2) T and reactive power increment and (k+1/2) T to (k+1) T and reactive power increment phase With, can be according to the active-power P in (k+1/2) T moment^mid(k) and reactive power Q^mid(k), the active-power P (k) in kT moment and reactive power Q (k), Calculate (k+1) T moment active power predicted value P₁And reactive power predicted value Q (k+1)₁(k+1):

$\left[\begin{array}{c}{P}_1(k+1)\\ Q_1(k+1)\end{array}\right]=2\left[\begin{array}{c}{P}^{mid}\left(k\right)\\ Q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}P\left(k\right)\\ Q\left(k\right)\end{array}\right]---\left(9\right)$

Step 5: be according to the grid-connected current in (k+1/2) T momentWithThe grid-connected current in kT moment is i_d(k) and i_qK (), calculates (k+1) grid-connected current predicted value i in T moment_d1And i (k+1)_q1(k+1):

$\left[\begin{array}{c}{i}_{d1}(k+1)\\ i_{q1}(k+1)\end{array}\right]=2\left[\begin{array}{c}{i}_d^{mid}\left(k\right)\\ i_q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}{i}_d\left(k\right)\\ i_q\left(k\right)\end{array}\right]---\left(10\right)$

Step 6: from formula (3), e_dAnd e_qIt is that frequency is | f₀-f₁| Low Frequency Sine Signals, for the most several kHz, the sample frequency of tens kHz, Adjacent amount can be considered as linear relation, therefore, can be according to the line voltage in (k+1/2) T momentWithThe electrical network electricity in kT moment Pressure is e_d(k) and e_qK (), calculates line voltage predicted value e in (k+1) T moment_d1And e (k+1)_q1(k+1):

$\left[\begin{array}{c}{e}_{d1}(k+1)\\ e_{q1}(k+1)\end{array}\right]=2\left[\begin{array}{c}{e}_d^{mid}\left(k\right)\\ e_q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}{e}_d\left(k\right)\\ e_q\left(k\right)\end{array}\right]---\left(11\right)$

Step 7: by formula (6), formula (7) and formula (8), calculates (k+1) T to (k+2) T moment current transformer output voltage vector v_dAnd v (k+1)_q(k+1):

$\left\{\begin{array}{c}{v}_d(k+1)=\frac{2L}{\[e_{d1}^2(k+1)+e_{q1}^2(k+1)\]3T}\left\{e_{d1}\right(k+1)\\ \[P_{ref}(k+2)-P_1(k+1)\]+e_{q1}(k+1)\[Q_{ref}(k+2)\\ -Q_1(k+1)\]\}+e_{d1}(k+1)-{\mathrm{\ω}}_{1}L{i}_{q1}(k+1)\\ v_q(k+1)=\frac{2L}{\[e_{d1}^2(k+1)+e_{q1}^2(k+1)\]3T}\left\{e_{q1}\right(k+1)\\ \[P_{ref}(k+2)-P_1(k+1)\]-e_{d1}(k+1)\[Q_{ref}(k+2)\\ -Q_1(k+1)\]\}+e_{q1}(k+1)+{\mathrm{\ω}}_{1}L{i}_{d1}(k+1)\end{array}\right.$

Wherein: P_ref(k+2) it is (k+2) T moment grid-connected active power reference value；Q_ref(k+2) it is (k+2) T moment grid-connected reactive power reference qref； L is three-phase grid inductance value；ω₁=2 π f₁t；f₁For controlling the frequency set；

Step 8: by current transformer output voltage vector v_dAnd v (k+1)_q(k+1) through Park inverse transformation, SVPWM modulation, current transformer power tube is exported Drive signal.

Matlab/Simulink is utilized to build 3-phase power converter circuit, drive circuit and Control System Imitation model, simulation parameter: U_dc=800V, L=0.6mH, 380Vac/50Hz three phase network, carrier frequency is 12kHz.Given meritorious and reactive power one timing, in simulation run process Frequency f that middle change control system sets₁The waveform obtained is as shown in Figure 4.Active power given in Fig. 4 is 20kW, and reactive power is 20kVAR, it can be seen that f₁Change procedure grid-connected current steady, setpoint frequency f in this explanation carried control method of the present invention₁With reality Mains frequency f₀Deviation do not affect control performance.

The above is only the preferred embodiment of the present invention, it is noted that for those skilled in the art, without departing from this On the premise of inventive technique principle, it is also possible to make some improvement and deformation, these improve and deformation also should be regarded as protection scope of the present invention.

Claims (2)

1. a no phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm, it is characterised in that comprise the following steps:

Step one: in (k-1) T, (k-1/2) T, kT, (k+1/2) T, (k+1) T, (k+3/2) T, (k+2) T moment, respectively to three-phase power grid voltage e_a、 e_b、e_cWith three-phase grid electric current i_a、i_b、i_cSampling, T is a triangular carrier cycle of PWM, and k is integer；

Step 2: three-phase power grid voltage step one sampling obtained and three-phase grid electric current convert through Clark conversion and Park respectively, are synchronized Three-phase power grid voltage vector e under rotating coordinate system_d、e_qWith three-phase grid current vector i_d、i_q；

Step 3: according to instantaneous power theory, calculates instantaneous active power P and reactive power Q:

$\left[\begin{array}{c}P\\ Q\end{array}\right]=\frac{3}{2}\left[\begin{array}{cc}{e}_d& e_q\\ e_q& -e_d\end{array}\right]\left[\begin{array}{c}{i}_d\\ i_q\end{array}\right]$

Step 4: according to the active-power P in (k+1/2) T moment^mid(k) and reactive power Q^mid(k), the active-power P (k) in kT moment and reactive power Q (k), calculates (k+1) T moment active power predicted value P₁And reactive power predicted value Q (k+1)₁(k+1):

$\left[\begin{array}{c}{P}_1(k+1)\\ Q_1(k+1)\end{array}\right]=2\left[\begin{array}{c}{P}^{mid}\left(k\right)\\ Q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}P\left(k\right)\\ Q\left(k\right)\end{array}\right]$

Step 5: according to the grid-connected current in (k+1/2) T momentWithGrid-connected current i in kT moment_d(k) and i_qK (), calculates (k+1) T Grid-connected current predicted value i in moment_d1And i (k+1)_q1(k+1):

$\left[\begin{array}{c}{i}_{d1}(k+1)\\ i_{q1}(k+1)\end{array}\right]=2\left[\begin{array}{c}{i}_d^{mid}\left(k\right)\\ i_q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}{i}_d\left(k\right)\\ i_q\left(k\right)\end{array}\right]$

Step 6: according to the line voltage in (k+1/2) T momentWithThe line voltage e in kT moment_d(k) and e_qK (), calculates (k+1) T Line voltage predicted value e in moment_d1And e (k+1)_q1(k+1):

$\left[\begin{array}{c}{e}_{d1}(k+1)\\ e_{q1}(k+1)\end{array}\right]=2\left[\begin{array}{c}{e}_d^{mid}\left(k\right)\\ e_q^{mid}\left(k\right)\end{array}\right]-\left[\begin{array}{c}{e}_d\left(k\right)\\ e_q\left(k\right)\end{array}\right]$

Step 7: calculate (k+1) T to (k+2) T moment current transformer output voltage vector v_dAnd v (k+1)_q(k+1):

$\left\{\begin{array}{c}{v}_d(k+1)=\frac{2L}{\[e_{d1}^2(k+1)+e_{q1}^2(k+1)\]3T}\{e_{d1}(k+1)\\ \[P_{ref}(k+2)-P_1(k+1)\]+e_{q1}(k+1)\[Q_{ref}(k+2)\\ -Q_1(k+1)\]\}+e_{d1}(k+1)-{\mathrm{\ω}}_1{\mathrm{Li}}_{q1}(k+1)\\ v_q(k+1)=\frac{2L}{\[e_{d1}^2(k+1)+e_{q1}^2(k+1)\]3T}\{e_{q1}(k+1)\\ \[P_{ref}(k+2)-P_1(k+1)\]-e_{d1}(k+1)\[Q_{ref}(k+2)\\ -Q_1(k+1)\]\}+e_{q1}(k+1)+{\mathrm{\ω}}_1{\mathrm{Li}}_{d1}(k+1)\end{array}\right.$

Wherein: P_ref(k+2) it is (k+2) T moment grid-connected active power reference value；Q_ref(k+2) it is (k+2) T moment grid-connected reactive power reference qref； L is three-phase grid inductance value；ω₁=2 π f₁t；f₁For controlling the frequency set；

Step 8: by current transformer output voltage vector v_dAnd v (k+1)_q(k+1) through Park inverse transformation, SVPWM modulation, current transformer power tube is exported Switching drive signal.

No phase-locked loop 3-phase power converter Direct Power forecast Control Algorithm the most according to claim 1, it is characterised in that carry out in step 2 During Park conversion, synchronous rotating frame and the angle theta=θ of rest frame₁+2πf₁T, t are the moment, phase angle theta₁For arbitrary value.