CN201388163Y - Inverter power supply for state tracking and numerical control - Google Patents

Abstract

The utility model discloses an inverter power supply for state tracking and numerical control, which is characterized in that the input terminal of a prefilter is connected with a reference vector ur; an output terminal of the prefilter is connected with a positive input terminal of a subtracter; an output terminal of the subtracter is connected with an input terminal of a delay module; an output terminal of the delay module is connected with a control terminal of an inverter and a second input terminal of a predictive observer; a first input terminal and a third input terminal of the predictive observer are connected with output terminals of a current sensor and a voltage sensor respectively; an output terminal of the predictive observer is connected with an input terminal of a state gain matrix; and an output terminal of the state gain matrix is connected with a negative input terminal of the subtracter. The output terminal of the inverter is connected with the input terminal of the voltage sensor and a load; a direct current terminal of the inverter is connected with a direct current power supply; and a load current of the inverter is connected with the input terminal of the current sensor. The inverter power supply has excellent dynamic and static characteristics and small waveform distortion of output voltage, and can be widely applied to various power supply systems containing alternating current stable power supplies.

Description

Inverter power supply with state tracking digital control

Technical Field

The utility model relates to a power conversion circuit, in particular to state tracking digital control's invertion power supply.

Background

The digital controller can overcome the defects of easy aging, low universality, complex structure and the like of the analog controller, so that the digital control is widely concerned. With the rapid development of micro-electronic technologies such as microprocessors, the application of digital control is more common. In order to fully exert the advantages of digital control, scholars at home and abroad successively put forward various digital control methods.

However, the digital controller of analog design is an indirect design, and any discretization method of the controller has response distortion, so that the control performance of the controller is far inferior to that of the analog controller. In addition, the repetitive control and the dead-beat control are two control methods specific to the digital controller, and the multi-aspect performance of the system is not considered at the same time. The repetitive control eliminates the steady-state error by using the periodic integration of the error signal according to the internal model principle, but the dynamic response speed is slow. The dead beat control determines the control quantity according to the reference signal and the dynamic model of the controlled object, so that the controlled quantity reaches the reference value within a sampling period time, and the dead beat control has a faster response speed, but the control precision of the dead beat control depends on the precision of the model parameters, the robustness is poor, and the stability or even the instability of the system can be reduced. Although the above digital control method which can exert the advantages of digital control is proposed, the method has disadvantages.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art and provide a state tracking digital control inverter power supply which has rapid and stable dynamic response; the total harmonic distortion of the output voltage is low under the condition of the nonlinear load, and the total harmonic distortion of the output voltage is also low under the conditions that the peak factor of the rated nonlinear load and the load current exceeds 3; the steady-state precision is high; and the structure is simple, and the cost is lower.

The utility model provides a state tracking digital control's invertion power supply, its characterized in that: the control end of the inverter is connected with the microprocessor, the output end of the inverter is connected with the input end of the voltage sensor and the load, the load current led out from the inverter is connected with the input end of the current sensor, the direct current end of the inverter is connected with the direct current power supply, and the output end of the voltage sensor and the output end of the current sensor are respectively connected with the microprocessor;

the microprocessor comprises a pre-filter, a prediction observer, a state gain matrix, a one-beat delay module and a subtracter; input terminal of prefilter and reference u_rThe output end of the prefilter is connected with the positive input end of the subtracter; the output end of the subtracter is connected with the input end of the one-beat delay module; the output end of the one-beat delay module is connected with the control end of the inverter and the second input end of the prediction observer; the first input end of the prediction observer is connected with the output end of the current sensor, and the third input end of the prediction observer is connected with the voltage sensorThe output end of the prediction observer is connected with the input end of the state gain matrix; the output end of the state gain matrix is connected with the negative input end of the subtracter.

Compared with the prior art, the utility model has the following advantage:

(1) when the half load is suddenly added or reduced, the dynamic transition process of the inverter power supply provided by the utility model does not exceed 0.8 ms; the instantaneous change rate of the output voltage is small, and the load adaptability is enhanced.

(2) Under various load conditions from no load to rated load, the voltage stabilization precision is high, and the steady-state error is greatly reduced.

(3) The total harmonic distortion of the output voltage is low under the condition of the nonlinear load, and the total harmonic distortion of the output voltage is also low under the conditions that the peak factor of the load current exceeds 3 under the rated nonlinear load, so that the waveform distortion caused by the nonlinear load is more strongly inhibited.

(4) The utility model discloses in the inverter power supply design to state tracking digital control, adopt state tracking control and system pole point configuration method to guarantee inverter power supply's stability, dynamic behavior and reduce steady state error, whole electrical power generating system has stronger robustness. Under various load disturbance conditions, alternating current output voltage with excellent quality can be obtained; the whole inverter is insensitive to the parameter change of the inverter and the state tracking digital controller, and the system response performance is stable.

(5) The utility model discloses circuit structure is simple, and is with low costs, easily realizes.

Drawings

FIG. 1 is a schematic diagram of a state-tracking digitally controlled inverter power supply;

FIG. 2 is a flowchart of a main program of the microprocessor;

FIG. 3 is a first schematic block diagram of the control algorithm of FIG. 1;

FIG. 4 is a flowchart of the control algorithm routine of FIG. 2;

FIG. 5 is a second functional block diagram of the control algorithm of FIG. 1;

fig. 6 is a flow chart of the control algorithm routine of fig. 2.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

As shown in fig. 1, the structure of the inverter power supply with state tracking digital control provided by the utility model is as follows:

input of prefilter 7 and reference u_rAnd the output end of the pre-filter 7 is connected with the positive input end of the subtracter 10. The output end of the subtracter 10 is connected with the input end of the one-beat delay module 11. The output end of the one-beat delay module 11 is connected with the control end of the inverter 2 and the second input end of the prediction observer 8. The first input end of the prediction observer 8 is connected with the output end of the current sensor 6, the third input end of the prediction observer 8 is connected with the output end of the voltage sensor 5, and the output end of the prediction observer 8 is connected with the input end of the state gain matrix 9. The output terminal of the state gain matrix 9 is connected with the negative input terminal of the subtracter 10. The output end of the inverter 2 is connected with the input end of the voltage sensor 5 and the load 3, and the direct current end of the inverter 2 is connected with the direct current power supply 4. The load current in the inverter 2 is connected to the input of the current sensor 6.

The inverter 2, the voltage sensor 5, and the current sensor 6 may be selected from conventional inverters, voltage sensors, and current sensors.

The pre-filter 7, the prediction observer 8, the state gain matrix 9, the one-beat delay module 11 and the subtractor 10 constitute a microprocessor 1. The microprocessor can be a single chip microcomputer or a digital signal processing chip.

Load current i in inverter 2_oAnd an output voltage u₀Respectively sent to the microprocessor 1 through the current sensor 6 and the voltage sensor 5, and the microprocessor 1 generates a control signal u after program operation₁The inverter 2 is controlled.

The control method adopted by the state tracking digital control is shown in fig. 2. A schematic diagram and a program flow chart of a control algorithm of the state tracking I type are shown in FIGS. 3 and 4, wherein the state variable is the integral of the output voltage, the inverter current, the output voltage and the double integral of the output voltage; a schematic diagram and a program flowchart of a control algorithm using an integral of an output voltage, an inverter current, and an output voltage as a state variable, called a state tracking type II, are shown in fig. 5 and 6. The method comprises the following specific steps:

(1) collecting output voltage u of current beat obtained by voltage sensor_o(k) And the current sensor obtains the current of the current beat i_o(k) And k represents the serial number of the current beat, and one sampling period T is called one beat in the digital control system.

(2) Calculating a voltage prediction error e using equation (A)_uo(k)

$e_{\mathrm{uo}}\left(k\right)=u_o\left(k\right)-{\hat{u}}_o\left(k\right)---\left(A\right)$

Wherein,

the predicted value of the output voltage at the k-1 th beat is obtained.

(3) Calculating the control signal u after repeated compensation by formula (B)₁’(k)

$\left\{\begin{array}{c}{u}_{\mathrm{rept}}\left(k\right)={\mathrm{Qu}}_{\mathrm{retp}}(k-N)+k_r{e}_{\mathrm{uo}}(k-N+k_z)\\ u_i^{,}\left(k\right)=u_1\left(k\right)+u_{\mathrm{rept}}\left(k\right)\end{array}\right.---\left(B\right)$

Wherein u is_rept(k) For repeated compensation, u₁(k) For the control signal of the kth beat, N is the sampling frequency of a fundamental wave period, Q is a quasi-integral coefficient, Q is more than or equal to 0.9 and less than 1, and usually 0.95 is taken, k_rFor repetitive gain, 0 < k_r≤0.5，k_zTo advance the beat number, the phase angle lag of equation (C) is compensated.

(4) Calculating the predicted value of the output voltage of the next beat by using the formula (C)

And the predicted value of the filter inductance current of the next beat

$\left[\begin{array}{c}{\hat{u}}_0(k+1)\\ {\hat{i}}_1(k+1)\end{array}\right]=(A_s-H_s{C}_s)\left[\begin{array}{c}{\hat{u}}_0\left(k\right)\\ {\hat{i}}_1\left(k\right)\end{array}\right]+B_s\left[\begin{array}{c}{u}_1^{,}\left(k\right)\\ i_0\left(k\right)\end{array}\right]+H_s{C}_s\left[\begin{array}{c}{u}_0\left(k\right)\\ 0\end{array}\right]---\left(C\right)$

In the formula <math> <mrow> <msub> <mi>A</mi> <mi>s</mi> </msub> <mo>=</mo> <mfenced open='[' close=']'> <mtable> <mtr> <mtd> <msub> <mi>&phi;</mi> <mn>11</mn> </msub> </mtd> <mtd> <msub> <mi>&phi;</mi> <mn>12</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>&phi;</mi> <mn>21</mn> </msub> </mtd> <mtd> <msub> <mi>&phi;</mi> <mn>22</mn> </msub> </mtd> </mtr> </mtable> </mfenced> <mo>,</mo> </mrow> </math>

<math> <mrow> <msub> <mi>&phi;</mi> <mn>11</mn> </msub> <mo>=</mo> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>cos</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>+</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>,</mo> <msub> <mi>&phi;</mi> <mn>12</mn> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <mrow> <mi>C</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> </mrow> </math>

<math> <mrow> <msub> <mi>&phi;</mi> <mn>21</mn> </msub> <mo>=</mo> <mo>-</mo> <mfrac> <mn>1</mn> <mrow> <mi>L</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>,</mo> <msub> <mi>&phi;</mi> <mn>22</mn> </msub> <mo>=</mo> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>cos</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> </mrow> </math>

B_s＝[H₁ H₂]

<math> <mrow> <msub> <mi>H</mi> <mn>1</mn> </msub> <mo>=</mo> <mfenced open='[' close=']'> <mtable> <mtr> <mtd> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mrow> <mo>(</mo> <mo>-</mo> <mi>cos</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>)</mo> </mrow> <mo>+</mo> <mn>1</mn> </mtd> </mtr> <mtr> <mtd> <mfrac> <mn>1</mn> <mrow> <mi>L</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> </mtd> </mtr> </mtable> </mfenced> <mo>=</mo> <mfenced open='[' close=']'> <mtable> <mtr> <mtd> <msub> <mi>h</mi> <mn>11</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>h</mi> <mn>12</mn> </msub> </mtd> </mtr> </mtable> </mfenced> </mrow> </math>

<math> <mrow> <msub> <mi>H</mi> <mn>2</mn> </msub> <mo>=</mo> <mfenced open='[' close=']'> <mtable> <mtr> <mtd> <mi>r</mi> <mrow> <mo>(</mo> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>cos</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>+</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>-</mo> <mfrac> <mn>1</mn> <mrow> <mi>C</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> </mtd> </mtr> <mtr> <mtd> <mo>-</mo> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>cos</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> </mrow> </mfrac> <msup> <mi>e</mi> <mrow> <mo>-</mo> <mfrac> <mi>r</mi> <mrow> <mn>2</mn> <mi>L</mi> </mrow> </mfrac> <mi>T</mi> </mrow> </msup> <mi>sin</mi> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mi>T</mi> <mo>+</mo> <mn>1</mn> </mtd> </mtr> </mtable> </mfenced> <mo>=</mo> <mfenced open='[' close=']'> <mtable> <mtr> <mtd> <msub> <mi>h</mi> <mn>12</mn> </msub> </mtd> </mtr> <mtr> <mtd> <msub> <mi>h</mi> <mn>22</mn> </msub> </mtd> </mtr> </mtable> </mfenced> </mrow> </math>

C_s＝[1 0]

<math> <mrow> <msub> <mi>&omega;</mi> <mi>n</mi> </msub> <mo>=</mo> <mfrac> <mn>1</mn> <msqrt> <mi>LC</mi> </msqrt> </mfrac> <mo>,</mo> </mrow> </math> Is the natural oscillation frequency of the inverter 2

<math> <mrow> <msub> <mi>&omega;</mi> <mi>d</mi> </msub> <mo>=</mo> <msqrt> <mfrac> <mn>1</mn> <mi>LC</mi> </mfrac> <mo>-</mo> <mfrac> <msup> <mi>r</mi> <mn>2</mn> </msup> <mrow> <mn>4</mn> <msup> <mi>L</mi> <mn>2</mn> </msup> </mrow> </mfrac> </msqrt> <mo>,</mo> </mrow> </math> For damping oscillation frequency of inverter 2

Wherein,

respectively obtaining a predicted value of the output voltage of the current beat and a predicted value of the current of the filter inductor, wherein L is the total filter inductor output by the inverter 2, C is the total filter capacitor output by the inverter 2, and r is the equivalent damping resistance of the inverter 2; h_sTo predict the feedback gain matrix, one can follow (A)_s-H_sC_s) Is selected on the basis of the principle that the characteristic value of (2) is faster than the closed-loop characteristic value of the inverter by more than 3 times.

(5) Calculating the integral predicted value of the output voltage of the next beat by using a formula (D1)

${\hat{u}}_i(k+1)=T{\hat{u}}_0(k+1)+{\hat{u}}_i\left(k\right)---\left(D1\right)$

Integrating and predicting the output voltage integral of the k-th beat obtained in the k-1 st beat;

if the state tracking type I is adopted, the double integral predicted value of the output voltage of the next beat is calculated by using a formula (D2)

${\hat{u}}_{\mathrm{ii}}(k+1)-T{\hat{u}}_i(k+1)+{\hat{u}}_{\mathrm{ii}}\left(k\right)---\left(D2\right)$

The predicted value is doubly integrated for the output voltage at the k-1 th beat.

(6) Calculating a state tracking control signal u_f(k+1)：

(6A) When the state tracking type I is adopted, the next beat of the state tracking control signal u is calculated using the formula (E1)_f(k+1)：

$u_f(k+1)=k_4\hat{i}(k+1)+k_3{\hat{u}}_o(k+1)+k_2{\hat{u}}_i(k+1)+k_1{\hat{u}}_{\mathrm{ii}}(k+1)---\left(E\right)$

Wherein k is₁、k₂、k₃、k₄The elements in the digitally controlled state gain matrix K are tracked for state.

At the state variable being the output voltage u_oInverter current i, integral u of output voltage_iAnd double integral u of the output voltage_iiAt this time, the state tracks the discrete state equation of the digital control inverter power supply: x (k +1) ═ F₁X(k)+G₁u₁(k) In which F is₁、G₁State matrix and input matrix; desired closed loop pole P ═ { z > of the system in the discrete domain₁ z₂ z₃ z₄Using Ackermamn formula to obtain K ═ K₁ k₂ k₃ k₄]Each element of (1).

The predicted value of the inverter current may be an inductor current or a capacitor current. When the inductive current is adopted, the predicted value of the current of the inverter is obtained in the next beat $\hat{i}(k+1)={\hat{i}}_1(k+1);$ When the capacitance current is adopted, the predicted value of the current of the inverter is obtained in the next beat $\hat{i}(k+1)={\hat{i}}_1(k+1)-{\hat{i}}_o(k+1),$ Wherein the next beat of load current is predicted

Can be calculated from equation (F):

$\left[\begin{array}{c}{\hat{i}}_o(k+1)\\ {\hat{i}}_o(k+1)\end{array}\right]=A_d\left[\begin{array}{c}{\hat{i}}_o\left(k\right)\\ {\hat{i}}_o\left(k\right)\end{array}\right]+H_d{C}_d\left[\begin{array}{c}0\\ i_o\left(k\right)-{\hat{i}}_o\left(k\right)\end{array}\right]---\left(F\right)$

in the formula $A_d=\left[\begin{array}{cc}1& 0\\ \mathrm{<figure-callout\; id="1"\; label="T"\; filenames="Y2009200852240011H1.png,Y2009200852240011H2.png"\; state="\{\{state\}\}">T</figure-callout>}& 1\end{array}\right],$ C_d＝[0 1]，

The load current predicted value for the k-th beat obtained at the k-1 st beat,

is composed of

The differential value of (a) is determined,is composed of

The differential value of (a).

H_dTo perturb the feedback gain matrix, one may follow (A)_d-H_dC_d) Is selected 5 times faster than the closed-loop characteristic of the inverter 2.

(6B) When the state tracking type II is adopted, the next beat of the state tracking control signal u is calculated using the formula (E2)_f(k+1)：

<math> <mrow> <msub> <mi>u</mi> <mi>f</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>=</mo> <msubsup> <mi>k</mi> <mn>3</mn> <mo>&prime;</mo> </msubsup> <mover> <mi>i</mi> <mo>^</mo> </mover> <mrow> <mo>(</mo> <mi>k</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>+</mo> <msubsup> <mi>k</mi> <mn>2</mn> <mo>&prime;</mo> </msubsup> <msub> <mover> <mi>u</mi> <mo>^</mo> </mover> <mi>o</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>+</mo> <msubsup> <mi>k</mi> <mn>1</mn> <mo>&prime;</mo> </msubsup> <msub> <mover> <mi>u</mi> <mo>^</mo> </mover> <mi>i</mi> </msub> <mrow> <mo>(</mo> <mi>k</mi> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>-</mo> <mo>-</mo> <mo>-</mo> <mrow> <mo>(</mo> <mi>E</mi> <mn>2</mn> <mo>)</mo> </mrow> </mrow> </math>

Wherein, k'₁、k’₂、k’₃The elements in the digitally controlled state gain matrix K' are tracked for state.

At the state variable being the output voltage u_oInverter current i, integral u of output voltage_iAt this time, the state tracks the discrete state equation of the digital control inverter power supply: x (k +1) ═ F₂X(k)+G₂u₁(k) In which F is₂、G₂A state matrix and an input matrix. Desired closed loop pole P '═ { z' of system in discrete domain₁ z₂ z₃Solving K' ═ K by Ackermamn formula₁’k₂’k₃’]Each element of (1)And (4) element.

(7) Calculating the output signal u of the prefilter_p(k+1)：

The calculation of the output signal of the prefilter according to the difference between the state tracking type I and the state tracking type II is described below.

(7A) When the state tracking type I is adopted, the parameters of the prefilter can be obtained according to the following formula:

k₇＝k₃-Ck_ii

wherein k is_iiIs composed of $C{k}_{\mathrm{ii}}^3-k_3{k}_{\mathrm{ii}}^2+k_2{k}_4{k}_{\mathrm{ii}}-k_1{k}_4^2=0$ The root of the plant,

k₆＝2k₇+k₃T，

k₅＝k₇+k₃T+k₄T²

according to the reference u of the next beat_r(k +1), current reference amount u of taking a beat_r(k) And the reference amount u of the last beat_r(k-1) calculating the prefilter next beat output signal u from equation (G1)_p(k+1)：

u_p(k+1)＝k₅u_r(k+1)-k₆u_r(k)+k₇u_r(k-1)+2u_p(k)-u_p(k-1) (G1)

u_p(k-1)、u_p(k) Respectively obtaining output signals of the pre-filters of the k-1 st beat and the k-1 st beat in the k-2 nd beat and the k-1 th beat;

(7B) when the state tracking type II is adopted, the parameters of the prefilter can be obtained according to the following formula:

k′₅＝k′₂+k′₁T

k′₆＝k′₂

according to the reference u of the next beat_r(k +1) and the current beat reference u_r(k) Calculating the next beat output signal u of the prefilter from the formula (G2)_p(k+1)：

u_p(k+1)＝k′₅u_r(k+1)-k′₆u_r(k)+u_p(k) (G2)

(8) Calculating the control signal u of the next beat by formula (H)₁(k+1)：

u₁(k+1)＝u_p(k+1)-u_f(k+1) (H)

(9) Next beat control signal u₁(k +1) after passing through a beat delay module, adjusting the inverter at the k +1 th beat;

(10) and (5) making k equal to k +1, and turning to the step (1) to be executed in a circulating mode.

Wherein k is,

e_uo、u_rept、u₁、

u_pThe initial values of the signals are all zero.

State tracking type I compared to state tracking type II: when the half load is suddenly added or reduced, the instantaneous change rate of the output voltage of the state tracking I type is 7.72 percent, and the instantaneous change rate of the output voltage of the state tracking II type is 10.29 percent; under various load conditions from no load to rated load, the voltage stabilization precision of the state tracking type I is within 0.79 percent, and the voltage stabilization precision of the state tracking type II is within 0.54 percent; under the condition of rated nonlinear load, THD of the state tracking type I is less than 1.2% when the current crest factor is 3.6, and THD of the state tracking type II is less than 2.52% when the current crest factor is 3.3.

The present invention is not limited to the above embodiments, and those skilled in the art can adopt other embodiments to implement the present invention according to the content disclosed in the examples and drawings, therefore, all the design structure and idea of the present invention can be adopted to make some simple changes or modified designs, and all fall into the protection scope of the present invention.

Claims (1)

1. A state tracking digitally controlled inverter power supply characterized by:

the control end of the inverter (2) is connected with the microprocessor (1), the output end of the inverter (2) is connected with the input end of the voltage sensor (5) and the load (3), the load current led out from the inverter (2) is connected with the input end of the current sensor (6), the direct current end of the inverter (2) is connected with the direct current power supply (4), and the output end of the voltage sensor (5) and the output end of the current sensor (6) are respectively connected with the microprocessor (1);

the microprocessor (1) comprises a pre-filter (7) to predict the observationsThe device comprises a device (8), a state gain matrix (9), a one-beat delay module (11) and a subtracter (10); the input of the prefilter (7) and the reference u_rThe output end of the prefilter (7) is connected with the positive input end of the subtracter (10); the output end of the subtracter (10) is connected with the input end of the one-beat delay module (11); the output end of the one-beat delay module (11) is connected with the control end of the inverter (2) and the second input end of the prediction observer (8); the first input end of the prediction observer (8) is connected with the output end of the current sensor (6), the third input end of the prediction observer (8) is connected with the output end of the voltage sensor (5), and the output end of the prediction observer (8) is connected with the input end of the state gain matrix (9); the output end of the state gain matrix (9) is connected with the negative input end of the subtracter (10).

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