阅读说明：本技术 一种三相逆变控制系统和控制方法 (Three-phase inversion control system and control method ) 是由 宁华宏 张登科 李化良 郑大为 于 2021-08-09 设计创作，主要内容包括：本发明提供一种三相逆变控制系统,包括瞬时值电压控制器和等效有效值电压控制器,其中,所述瞬时值电压控制器用于反馈控制逆变输出电压的瞬时值,所述等效有效值电压控制器对逆变输出电压的有效值进行正交分解反馈控制,其中,所述等效有效值电压控制器用于对三相逆变器两相旋转坐标系的实轴电压和虚轴电压分别进行积分补偿,所述瞬时值电压控制器和所述等效有效值电压控制器的输出被用于经过延迟环节传递函数和被控对象传递函数获得逆变输出电压。本发明的控制系统调节速度快、稳定性强。(The invention provides a three-phase inversion control system, which comprises an instantaneous value voltage controller and an equivalent effective value voltage controller, wherein the instantaneous value voltage controller is used for feedback control of an instantaneous value of an inversion output voltage, the equivalent effective value voltage controller is used for performing orthogonal decomposition feedback control on an effective value of the inversion output voltage, the equivalent effective value voltage controller is used for performing integral compensation on a real-axis voltage and a virtual-axis voltage of a two-phase rotation coordinate system of a three-phase inverter respectively, and the outputs of the instantaneous value voltage controller and the equivalent effective value voltage controller are used for obtaining the inversion output voltage through a delay link transfer function and a controlled object transfer function. The control system of the invention has fast regulating speed and strong stability.)

1. A three-phase inversion control system comprises an instantaneous value voltage controller and an equivalent effective value voltage controller, wherein the instantaneous value voltage controller is used for feedback control of an instantaneous value of an inversion output voltage, the equivalent effective value voltage controller is used for orthogonal decomposition feedback control of the effective value of the inversion output voltage, the equivalent effective value voltage controller is used for integral compensation of a real-axis voltage and a virtual-axis voltage of a two-phase rotation coordinate system of a three-phase inverter respectively, and outputs of the instantaneous value voltage controller and the equivalent effective value voltage controller are used for obtaining the inversion output voltage through a delay link transfer function and a controlled object transfer function.

2. The three-phase inversion control system according to claim 1, wherein the equivalent voltage effective value controller is an integral compensatorWherein, K_compIs the gain factor and s is the frequency domain operator.

3. The three-phase inverter control system according to claim 2, wherein the gain factor is less than 1.

4. A three-phase inverter control system according to any of claim 3, wherein the real axis voltage is represented as v_rThe virtual axis voltage is represented as v_iWherein, in the step (A),

wherein v is_{ref_sin}Representing a given value of the inverted sinusoidal voltage, v_{ref_cos}Representing inverted cosine voltage set-point, v_errRepresenting the difference between the set value of the inverted sinusoidal voltage and the output voltage of the inverter.

5. The three-phase inverter control system according to claim 4,wherein, V_rIs the mean value of the real axis voltage, V_iIs the average value of the voltage of the virtual axis,for the value of the real-axis voltage disturbance,is a virtual axis voltage perturbation value.

6. The three-phase inverter control system according to claim 5,andwherein, is Δ V_rmsThe difference value between the inverter voltage effective value and the feedback voltage effective value is given, w is the angular frequency of the inverter output voltage, and t is time.

7. The three-phase inversion control system of claim 6, wherein the integral compensator transforms the real shaft voltage v_rConverted into a real-axis output value V of the controller_reAnd applying said virtual axis voltage v_iConverted into controller virtual axis output value V_imWherein, in the step (A),

8. the three-phase inverter control system according to claim 7, wherein the controller-based real-axis output value V_reObtaining the equivalent duty ratio d of the real-axis voltage loop output_dBased on the virtual axis output value V of the controller_imObtaining the equivalent duty ratio d of the virtual axis voltage loop output_qAnd said momentary-value voltage controller D_vDuty cycle of(s) output d_DvThe total duty cycle is d, wherein d ═ d_Dv+d_d+d_q。

9. The three-phase inversion control system of claim 8, wherein the total duty cycle d is used to obtain the inverted output voltage via a delay-link transfer function and a controlled-object transfer function.

10. A three-phase inverter control system according to any of claims 1-9, wherein the instantaneous value voltage controller is a hysteretic controller, denoted as hysteretic controllerWherein K_fwIs the instantaneous value voltage controller gain coefficient, z is the instantaneous voltage loop controller zero, p is the instantaneous voltage loop controller pole, and s is the frequency domain operator.

11. The three-phase inversion control system according to any one of claims 1 to 9, further comprising a coordinate system conversion section for realizing conversion between an abc coordinate system and an α β γ coordinate system.

12. A three-phase inversion control method, comprising:

a step of feedback-controlling an instantaneous value of the inverted output voltage;

performing quadrature decomposition feedback control on the effective value of the inverter output voltage, which comprises respectively performing integral compensation on the real-axis voltage and the virtual-axis voltage of the two-phase rotating coordinate system of the three-phase inverter, and

and the output of the step of feedback controlling the instantaneous value of the inversion output voltage and the output of the step of carrying out orthogonal decomposition feedback control on the effective value of the inversion output voltage are used for obtaining the inversion output voltage through delay link transmission and controlled object transmission.

13. The three-phase inversion control method of claim 12, wherein a gain coefficient of the integral compensation is less than 1.

14. The three-phase inversion control method of claim 12, wherein the real axis voltage is represented as v_rThe virtual axis voltage is represented as v_iWherein, in the step (A),

wherein v is_{ref_sin}Representing a given value of the inverted sinusoidal voltage, v_{ref_cos}Representing inverted cosine voltage set-point, v_errRepresenting the difference between the set value of the inverted sinusoidal voltage and the output voltage of the inverter.

15. The three-phase inversion control method according to claim 12, further comprising converting the abc coordinate system into an α β γ coordinate system in a feedback process, and converting the α β γ coordinate system into the abc coordinate system in an output process.

16. The method of claim 12, further comprising the step of adjusting an initial phase angle of the inverter output voltage to zero.

Technical Field

The invention belongs to the field of inverters, and particularly relates to a three-phase inversion control system and a control method.

Background

The inverter is a converter which converts direct current electric energy of a battery, an accumulator jar and the like into constant frequency and constant voltage or frequency and voltage regulation alternating current. With the rapid development of science and technology, the requirements of people's life and production on power supply quality are higher and higher, and the inverter is the core part of power supply equipment such as an Uninterruptible Power Supply (UPS), a variable frequency power supply, a new energy power supply system and the like, so that the research on the inverter has an important significance on the development of modern industry. In the existing inversion control system, due to the existence of nonlinear factors, the quality of an output waveform of an inverter is deteriorated, and even the system is unstable. In the existing inversion control method, feedback control is directly carried out through current or voltage, and the method is slow in response speed and poor in stability.

Disclosure of Invention

Therefore, an object of the present invention is to overcome the above-mentioned drawbacks of the prior art, and provide a three-phase inverter control system, which includes an instantaneous value voltage controller and an equivalent effective value voltage controller, wherein the instantaneous value voltage controller is configured to perform feedback control on an instantaneous value of an inverter output voltage, and the equivalent effective value voltage controller performs quadrature decomposition feedback control on an effective value of the inverter output voltage, wherein the equivalent effective value voltage controller is configured to perform integral compensation on a real axis voltage and a virtual axis voltage of a two-phase rotation coordinate system of a three-phase inverter, and outputs of the instantaneous value voltage controller and the equivalent effective value voltage controller are used to obtain the inverter output voltage through a delay element transfer function and a controlled object transfer function.

According to the three-phase inversion control system of the present invention, preferably, the equivalent voltage effective value controller is an integral compensatorWherein, K_compIs the gain factor and s is the frequency domain operator.

According to the three-phase inversion control system of the present invention, preferably, the gain factor is smaller than 1.

According to the three-phase inversion control system of the present invention, preferably, the real axis voltage is represented as v_rThe virtual axis voltage is represented as v_iWherein, in the step (A),

wherein v is_{ref_sin}Representing a given value of the inverted sinusoidal voltage, v_{ref_cos}Representing inverted cosine voltage set-point, v_errRepresenting the difference between the set value of the inverted sinusoidal voltage and the output voltage of the inverter.

According to the three-phase inverter control system of the present invention, preferably,wherein, V_rIs the mean value of the real axis voltage, V_iIs the average value of the voltage of the virtual axis,for the value of the real-axis voltage disturbance,is a virtual axis voltage perturbation value.

According to the three-phase inverter control system of the present invention, preferably,andwherein, is Δ V_rmsThe difference value between the inverter voltage effective value and the feedback voltage effective value is given, w is the angular frequency of the inverter output voltage, and t is time.

According to the three-phase inversion control system of the present invention, preferably, the integral compensator converts the real axis voltage v_rConverted into a real-axis output value V of the controller_reAnd applying said virtual axis voltage v_iConverted into controller virtual axis output value V_imWherein, in the step (A),

the three-phase inversion control system according to the present invention is preferably based on a controller real-axis output value V_reObtaining the equivalent duty ratio d of the real-axis voltage loop output_dBased on the virtual axis output value V of the controller_imObtaining the equivalent duty ratio d of the virtual axis voltage loop output_qAnd said momentary-value voltage controller D_vDuty cycle of(s) output d_DvThe total duty cycle is d, wherein d ═ d_Dv+d_d+d_q。

According to the three-phase inversion control system of the present invention, preferably, the total duty ratio d is used to obtain the inversion output voltage through the delay link transfer function and the controlled object transfer function.

According to the three-phase inverter control system of the present invention, preferably, the instantaneous value voltage controller is a hysteresis controller expressed asWherein K_fwIs the instantaneous value voltage controller gain coefficient, z is the instantaneous voltage loop controller zero, p is the instantaneous voltage loop controller pole, and s is the frequency domain operator.

The three-phase inversion control system according to the present invention preferably further includes a coordinate system conversion section for realizing conversion between the abc coordinate system and the α β γ coordinate system.

The invention also provides a three-phase inversion control method, which comprises the following steps:

a step of feedback-controlling an instantaneous value of the inverted output voltage;

performing quadrature decomposition feedback control on the effective value of the inverter output voltage, which comprises respectively performing integral compensation on the real-axis voltage and the virtual-axis voltage of the two-phase rotating coordinate system of the three-phase inverter, and

and the output of the step of feedback controlling the instantaneous value of the inversion output voltage and the output of the step of carrying out orthogonal decomposition feedback control on the effective value of the inversion output voltage are used for obtaining the inversion output voltage through delay link transmission and controlled object transmission.

According to the three-phase inversion control method of the present invention, preferably, a gain coefficient of the integral compensation is less than 1.

According to the three-phase inversion control method of the present invention, preferably, the real axis voltage is represented as v_rThe virtual axis voltage is represented as v_iWherein, in the step (A),

wherein v is_{ref_sin}Representing a given value of the inverted sinusoidal voltage, v_{ref_cos}Representing inverted cosine voltage set-point, v_errRepresenting the difference between the set value of the inverted sinusoidal voltage and the output voltage of the inverter.

According to the three-phase inversion control method of the present invention, it is preferable that the method further includes converting the abc coordinate system into an α β γ coordinate system in a feedback process, and converting the α β γ coordinate system into the abc coordinate system in an output process.

According to the three-phase inversion control method of the present invention, it is preferable that the method further includes a step of adjusting an initial phase angle of the inverter output voltage to zero.

Compared with the prior art, the invention has the advantages that: compared with the traditional control system, the equivalent effective value voltage control loop can design larger crossing frequency, ensure enough fast adjustment speed and still have enough phase amplitude margin. Meanwhile, an integral controller in the system ensures that the stability is basically free of net difference, and the system has excellent performance in the aspect of dynamic/stability.

Drawings

Embodiments of the invention are further described below with reference to the accompanying drawings, in which:

fig. 1 and 2 show a three-phase four-wire inversion topology and a three-phase three-wire inversion topology, respectively;

fig. 3 is a simplified inversion control system for a three-phase four-wire inversion topology according to a first embodiment of the present invention.

Fig. 4 is an equivalent inverter control system according to a first embodiment of the present invention.

Fig. 5 is an open-loop bode plot of an equivalent effective value voltage loop according to a first embodiment of the present invention.

Fig. 6 shows the momentary-value voltage loop of fig. 4.

Fig. 7 is an open-loop bode plot of the instantaneous voltage loop shown in fig. 4.

Fig. 8 is a simplified inversion control system for a three-phase three-wire inversion topology according to a second embodiment of the present invention.

Fig. 9a and 9b show simulation results.

Fig. 10a and 10b show hardware-in-the-loop experimental test results.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail by embodiments with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

See fig. 1 and 2 for a three-phase four-wire inversion topology and a three-phase three-wire inversion topology. The supply voltage supplies power to the load through the inverter topology. Wherein, C_busA bus capacitor representing a single-sided bus; v_busRepresents the bus capacitor voltage; brg _ A _ X/Brg _ A _ Y, Brg _ B _ X/Brg _ B _ Y, Brg _ C _ X/Brg _ C _ Y respectively represent an inversion X, Y bridge arm of an A/B/C phase; l is_X,L_YRespectively representing the filter inductances of an inverter X bridge arm and an inverter Y bridge arm; i.e. i_{L_X},i_{L_Y}Respectively representing the current of the filter inductors of the inverter X bridge arm and the inverter Y bridge arm; c_invRepresents an inverter filter capacitor; LegX and LegY respectively represent an X arm and a Y arm of the three-phase inverter.

First embodiment

In this embodiment, the inverter control system and the inverter control method of the present invention are provided based on the three-phase four-wire inverter topology shown in fig. 1, and the control object of the control system and the control method of this embodiment is the three-phase four-wire inverter topology shown in fig. 1. For simplicity, only phase a is discussed as an example, and those skilled in the art will understand that phase B and phase C are similar to phase a, and ABC are used herein to refer to the three phases of a three-phase inverter.

See fig. 3 for aThe simplified inverter control system of (1). Firstly, V is given based on the effective value of the inverter voltage_{rms_ref}Obtaining given value v of inverted sine voltage_{ref_sin}And inverted cosine voltage given value v_{ref_cos}，

Wherein w is the angular frequency of the inverter output voltage, and t is time. As is known to those skilled in the art, a given value is also referred to as a reference value, which is a desired value of the inverter output.

Suppose that

Wherein v is_oFor inverting the output voltage (i.e. the feedback voltage), V_{rms_o}In order to invert the effective value of the output voltage, θ is the initial phase angle of the inverted voltage, and in the present invention, θ is required to be 0 for the convenience of control.

Then it is determined that,

v_err＝v_{ref_sin}-v_o＝V_{rms_ref}sin(wt)-V_{rms_o}sin(wt)＝ΔV_rmssin(wt)，

wherein v is_errFor inverting the difference, Δ V, between a given value of sinusoidal voltage and a feedback voltage_rmsThe difference between the effective value of the inverter voltage and the effective value of the feedback voltage is given. In the field of circuit control, the feedback voltage is sinusoidal and therefore the feedback signal will not mark a sinusoidal sign in the discussion of the present invention.

Will contain the feedback voltage v_oV is_errRespectively inputting the real-axis voltage v and the inverse sine voltage given value and the inverse cosine voltage given value into a multiplier to obtain the real-axis voltage v_rAnd virtual axis voltage v_i，

Thus, it is possible to provide

The inverter voltage effective value is given and normalized to a per unit value pu, namely V_{rms_ref}Pu denotes a relative unit system, which is a common term in the engineering field. For example, the standard value of the inverter voltage is 230V, which is expressed by 1pu, and then (1+ 15%). 230V is 1.15 pu.

Then equation (2) can be simplified as:

the real axis voltage and the imaginary axis voltage are further represented as including a constant part (direct current amount) and a disturbance part (alternating current amount), respectively:

wherein, V_rIs the mean value of the real axis voltage, V_iIs the average value of the voltage of the virtual axis,for the value of the real-axis voltage disturbance,is a virtual axis voltage perturbation value.

The solid shaft part is provided with a solid shaft part,

an imaginary axis part of the shaft, and a part of the shaft,

according to the derivation, the real-axis voltage and the virtual-axis voltage of the two-phase rotating coordinate system of the three-phase inverter are obtained, and the real-axis voltage and the virtual-axis voltage are respectively written into a form containing the direct current quantity and the alternating current quantity.

Further performing compensation control on the real-axis voltage and the virtual-axis voltage, starting from the decomposition formulas (3), (4) and (5), adding an integral compensator (also called an integral controller),wherein, in the present invention, D_ri(s) is an effective value voltage controller for controlling the real axis voltage and the imaginary axis voltage, and is referred to as an "equivalent effective value voltage controller" in the present invention in order to distinguish the conventional effective value voltage controllers. K_compIn order to control the gain factor of the controller,for the controller integration part, s is the frequency domain operator.

Then it is determined that,

wherein, V_reFor the real-axis output value of the controller, V_imAnd outputting the value for the virtual axis of the controller.

Substituting the formula (3) into the formula (6),

because, it is known that

Therefore, the disturbance part is ignored to obtain

As can be seen from equation (8), in this embodiment, the effective value of the inverter voltage after the quadrature decomposition includes a real part V_reAnd an imaginary part V_imAnd imaginary part V_imEqual to zero, which is equivalent to an instantaneous effective value voltage control system. Thereby proving the aforementioned pushThe correctness and rationality of the process.

Continuing with reference to the simplified inverter control system shown in fig. 3. Wherein the voltage is controlled by an instantaneous value voltage controller D_v(s) controlling the inverter output voltage transient. d_DvDuty ratio of output of instantaneous voltage controller, d_dDuty cycle of output for equivalent real-axis voltage loop, d_qDuty ratio, G, of equivalent virtual axis voltage loop output_delay(s) is a digitally controlled delay-element transfer function, G_vd(s) is the controlled object transfer function of the voltage loop, i.e. the mathematical control obtained by the hardware Ralstonia transformation of the three-phase inverter, V_busThe voltage of a bus capacitor, L of an inverter filter inductor, C of an inverter filter capacitor and R of a load equivalent resistance value are different, and the parameters of controlled objects (inverter topology) are different, and transfer functions are also different. And the total duty ratio d is subjected to a delay link transfer function and a controlled object transfer function to obtain an inversion output voltage.

In the case of the normalization, the normalization is carried out,

based on the above, the duty ratio of the output of the equivalent real-axis voltage loop and the duty ratio of the output of the equivalent virtual-axis voltage loop can be further obtained,

in the known manner, it is known that,it represents the equivalent effective value voltage controller of the present invention because of the effective value error av_rmsCan be calculated quickly, and the calculation period is the control period T_sE.g. hereSo that the controller outputs V_reThe reference value V can be reached quickly_{rms_ref}I.e. V_re≈V_{rms_ref}) (ii) a While the conventional effective valueThe error calculation period is the commercial power period T_oThe power supply is controlled by the controller, such as the commercial power 50Hz/20ms,it can be seen that the bandwidth (i.e. the crossover frequency f) of the equivalent-value voltage controller of the present invention_{c_new}) Can be configured to be much larger than the ride-through frequency f of a conventional RMS voltage controller_{c_ori}Crossing frequency of equivalent-value voltage controller according to the inventionThe crossing frequency of the conventional RMS voltage controller is usuallyThis means that the regulation speed of the equivalent effective value voltage controller of the present invention is faster than that of the conventional control method, and in addition, because of the integration section, the control method of the present invention basically has no steady-state error.

The whole inversion control system of the embodiment is equivalent to a voltage inner-outer ring system, the inner ring is a voltage instantaneous value open-loop system, and the outer ring is a voltage effective value closed-loop system. Wherein the instantaneous value voltage controller D_v(s) the convergence of the initial state of the system can be ensured, and the system dynamics can be improved a little; and the virtual axis branch in the voltage effective value closed-loop system can ensure that the initial phase angle theta of the inversion voltage is zero. Delta V under system steady state_rms≈0，d_d≈V_{rms_ref}sin(wt)，d_q0, total duty ratio d ═ d_Dv+d_d+d_q≈d_dI.e. d_Dv0, so the instantaneous value voltage controller D_v(s) the weight fraction is small in the steady state.

Referring to the equivalent inverter control system shown in fig. 4, it clearly shows a voltage inner and outer loop system, wherein the inner loop is an equivalent instantaneous voltage open loop 3, which is equivalent to the instantaneous voltage loop 1, and the outer loop is an equivalent voltage effective closed loop 2. Wherein, V_{rms_o}For inverting the effective value of the output voltage, e^-sTAs a delay-loop transfer function, G_{v_ol}(s) is the transfer function of the momentary voltage loop 1, equivalently the momentary voltage open loop 3.

The equivalent effective value voltage loop is specifically analyzed below with reference to fig. 4. The controller isThe control object is G_delay(s)＝e^-sT，Performing equivalent linearization of Pade (Pade), designing a controller, performing open loop and closed loop of the system,

equivalent voltage effective value open loop transfer function G_{rms_ol}(s)＝D_ri(s)G_delay(s)，

Equivalent voltage effective value closed loop transfer function

Designing an appropriate PM/GM to obtain the parameter K_comp. Wherein, pm (phase margin) is a phase margin; GM (gain margin) is the amplitude margin. Note that D_riAn integral controller is necessary.

See FIG. 5 for an open-loop Baud diagram of an equivalent RMS voltage loop in which the loop crossing frequency f is_{c_ri}16.6Hz, phase margin PM_ri89.6deg, amplitude margin GM_riAbout 48.2dB, in the field of inversion control, GM is usually required>6，PM>30, it can be seen that the design of this embodiment meets performance requirements.

The momentary voltage loop of fig. 4 is discussed below. For the sake of clarity, fig. 6 shows the momentary-value voltage ring 1 of fig. 4 exclusively. Wherein the selection is exemplary and not limitingIt denotes a hysteresis controller, where K_fwIs the gain coefficient of the instantaneous voltage loop controller, z is the zero of the instantaneous voltage loop controller, p is the pole of the instantaneous voltage loop controller, and s is the frequency domain operator. In the present invention, instantaneous value voltageThe loop controller may also select other types of controllers known in the art as long as they can ensure convergence of the initial state of the system and take up less weight in the steady state.

See FIG. 7 for an open-loop Bode plot of an instantaneous voltage loop, where the crossover frequency f_{c_v}15.9Hz, phase margin PM_v116deg, gain margin GM_vAt 37.1dB, the momentary voltage loop is weighted less, about 0 in steady state, so the crossover frequency can be configured lower. The crossing frequency of the conventional instantaneous voltage controller usually reaches above 100Hz, and the crossing frequency of the instantaneous voltage loop of the invention is obviously lower than the conventional standard.

Second embodiment

In this embodiment, an inverter control system for the three-phase three-wire inverter topology shown in fig. 2 is provided, see the simplified schematic diagram of the three-phase three-wire inverter three-phase control system shown in fig. 8. It adds a coordinate system conversion part to the control system shown in fig. 3, where abc/α β γ denotes a conversion part of the abc coordinate system into an α β γ coordinate system, and α β λ/abc denotes an inverse conversion part of the α β γ coordinate system into the abc coordinate system. In the electrical field, a three-phase system includes a three-phase abc stationary coordinate system, a three-phase α β γ stationary coordinate system, and a two-phase rotating coordinate system dqo, and after coordinate system transformation, the inverted voltage V of a controlled object is inverted_{inv_α}V_{inv_β}Still in sine-cosine fundamental wave control, and the controller still adopts an instantaneous value voltage controller D_v(s) and equivalent-effective-value voltage controller D_ri(s); inverted voltage V_{inv_γ}Namely 3-harmonic control, the utilization rate of direct current voltage is improved by injecting 3-harmonic

The inventor respectively proves the effect of the invention through the results of simulation and hardware-in-loop (HIL) experimental test.

See simulation results shown in fig. 9a and 9 b. FIG. 9a shows the inverted abc phase voltage V under the steady state condition of full load from top to bottom_{inv_abc}And abc phase inductive current I of inverter bridge arms x and y_{inv_abc_xy}And outputs abc phase current I_{o_abc}The signals are normal and there is essentially no net difference. FIG. 9b shows the steady state condition at full loadThe harmonic data of the voltage a phase is inverted, wherein the total distortion rate THDv of the voltage harmonics is 0.88%, which meets the steady-state performance requirement of the product, and those skilled in the art can understand that there will be similar harmonic data for the b phase and the c phase.

See the results of the HIL experimental tests shown in fig. 10a and 10 b. FIG. 10a shows the load is changed from 0%>100% transient process, inverting abc phase voltage V_{inv_abc}A-phase inductive current I of inverter bridge arm x_{inv_a_x}In the load process, the signal is stable, and the dynamic period is about less than 1 commercial power period for 20 ms. FIG. 10b shows the load from 100%>The result of 0% unloading process shows that the inversion voltage and current are stable, and the dynamic process is less than the period of the commercial power. Therefore, the inverter is stable under the dynamic condition of the load, and the dynamic performance and the steady-state net difference meet the requirements.

Generally, the invention provides a novel inversion voltage orthogonal decomposition method, which comprises the steps of obtaining real-axis voltage and virtual-axis voltage, decomposing the direct current quantity and the disturbance quantity of the real-axis voltage through a small signal analysis method, and obtaining the direct current quantity and the disturbance quantity of the virtual axis in the same way. Based on a novel voltage orthogonal decomposition method, a novel inversion voltage controller is designed, and the inversion voltage controller comprises an equivalent effective value voltage controller and an instantaneous value voltage controller. On the three-phase inverter, design a complete novel three-phase contravariant control system, compare traditional contravariant control system, on the control of effective value voltage, this novel system is more better than traditional on developments and steady state nature. And the instantaneous value voltage control loop is equivalent to an open loop system, so that the inverter parallel operation system can be applied, and the performance is not inferior to the traditional system.

One of the effects of the inverter control system of the invention is that the equivalent effective value voltage control loop can design larger crossing frequency compared with the traditional control system, ensure enough fast regulation speed and still have enough phase amplitude margin. Meanwhile, an integral controller part in the system ensures that the stability is basically free of net difference, and the system has excellent performance in the aspect of dynamic/stability.

Although the present invention has been described by way of preferred embodiments, the present invention is not limited to the embodiments described herein, and various changes and modifications may be made without departing from the scope of the present invention.