CN110198055B - Micro-grid bidirectional converter control and stability analysis method based on virtual synchronous machine - Google Patents
Micro-grid bidirectional converter control and stability analysis method based on virtual synchronous machine Download PDFInfo
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Abstract
A micro-grid bidirectional converter control method based on a virtual synchronous machine and stability analysis are provided, wherein an integrator is added in a rotor motion equation damping link, and an angular frequency deviation value is fed back and compensated, so that the indifferent control of the alternating current sub-grid frequency in a micro-grid off-grid mode is realized. Considering the bidirectional transmission characteristic of the converter, the control target is switched from the alternating frequency to the direct current voltage in real time by changing a given mode of the virtual mechanical active power reference value, so that the stable control of the direct current bus voltage is realized. And respectively solving transfer functions of the converter under frequency control and direct current voltage control modes by establishing a power inner loop and a voltage/frequency outer loop small signal model, and carrying out stability analysis. The invention can well realize the indifferent adjustment of the frequency and the stable control of the direct current voltage in the off-grid mode.
Description
Technical Field
The invention relates to an alternating current-direct current hybrid microgrid bidirectional converter. In particular to a micro-grid bidirectional converter control and stability analysis method based on a virtual synchronous machine.
Background
With the increasing environmental and energy problems in the world today, various distributed power sources (photovoltaic, wind, etc.) are gaining high attention by the relevant scholars. Micro-networks were originally proposed by the american scholars professor r.h.lasseter to provide an efficient way for distributed access to distribution networks. With the increase of the types and the increase of the number of distributed power sources and the popularization of direct current loads, the structure of a power distribution network is complex and various, and an alternating current micro-grid is difficult to comprehensively meet the increasing power supply demands. In order to ensure the efficient utilization of new energy and renewable energy and better meet the diversified power demands of users, an AC/DC hybrid micro-grid is generated. The AC/DC hybrid micro-grid has the advantages of both AC micro-grid and DC micro-grid, and belongs to the current research hot spot. The alternating current area and the direct current area are connected through a micro-grid bidirectional converter, and the micro-grid bidirectional converter plays an important role in maintaining power balance in an alternating current-direct current hybrid micro-grid.
However, more and more new energy sources are integrated into the power grid, so that the permeability of various distributed power sources in the power system is higher and higher, and the corresponding traditional synchronous generator power source gradually reduces the duty ratio in the whole power system. The distributed power supply with the power electronic device as an interface lacks inertia and damping of the traditional motor, and when the system has power fluctuation or faults, the rapid fluctuation of the frequency of the power grid is difficult to restrain. The appearance of virtual synchronous machine (virtual synchronous generator, VSG) control technology enables power electronic devices to simulate characteristics of synchronous generators, namely characteristics of inertia, damping and the like, effectively solves the problem of insufficient inertia damping of a power system due to distributed power supply access, and has been widely paid attention in recent years. When the AC/DC hybrid micro-grid operates in the off-grid mode, the system voltage and frequency should be kept stable, and the transient process should be kept small in the off-grid switching process. However, the traditional virtual synchronous machine control has frequency deviation, and belongs to differential regulation.
Disclosure of Invention
The invention aims to solve the technical problem of providing a micro-grid bidirectional converter control and stability analysis method based on a virtual synchronous machine, which can realize the non-deviation adjustment of the frequency of a micro-grid alternating current bus.
The technical scheme adopted by the invention is as follows: a microgrid bidirectional converter control method based on a virtual synchronous machine is characterized in that an integration link is connected in parallel to a rotor motion equation damping link in existing virtual synchronous machine control, a rotor motion equation is changed from a first-order equation to a second-order equation, and the integration link is that
Where s is Laplacian, K i The integration coefficient of the integration link is defined by +.>
Determining a value range, wherein xi represents the damping ratio of the closed loop transfer function of the active power loop, D represents a damping coefficient and X s Is the total output reactance of the micro-grid bidirectional converter after introducing virtual impedance, E 0 Representing output potential of micro-grid bidirectional converter under steady state operation condition, U e0 Is in steady state operationUnder the condition of voltage omega of output port of micro-grid bidirectional converter 0 For grid synchronous angular velocity, J is the moment of inertia of the synchronous generator.
The second-order equation of the rotor motion is as follows:
wherein K is i The integral coefficient of the integral link is J, the moment of inertia of the synchronous generator and omega 0 For synchronous angular velocity of the power grid, ω is the actual angular velocity of the power grid, d is a differential operator, t is time, P m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter e And the active power output by the micro-grid bidirectional converter is represented, D is a damping coefficient, and s is a Laplacian operator.
Changing a given mode of virtual mechanical active power in virtual synchronous machine control from unidirectional selection to bidirectional selection, specifically, when the AC sub-network has power shortage, the transmission power of the micro-network bidirectional converter is positive, and the control target is the AC sub-network frequency; when the direct current sub-network has power shortage, the transmission power of the micro-network bidirectional converter is negative, and the control target is the direct current bus voltage.
The frequency formula of the alternating current sub-network is as follows:
P m ＝P ref +k f (f ref -f)
wherein P is m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter ref And f ref Active power reference value and system frequency reference value, k respectively output by micro-grid bidirectional converter f Is a frequency adjustment coefficient;
the formula of the direct current bus voltage is as follows:
wherein U is dc Indicating the voltage of the DC bus, U dc_ref Representing direct currentBus voltage reference value k pu And k pi The proportional and integral coefficients of the dc bus voltage PI regulator are shown, respectively.
A stability analysis method for micro-grid bidirectional converter control based on a virtual synchronous machine is to carry out stability analysis on the micro-grid bidirectional converter control method by establishing a small signal model of the output power of the micro-grid bidirectional converter, and specifically comprises the following steps:
1) Active power P output by rotor motion second-order equation and micro-grid bidirectional converter e And reactive power Q e Output potential equation of micro-grid bidirectional converter
The variables in (a) are expressed as the sum of the steady-state quantity and the disturbance quantity, i.e
Wherein K is q E represents the output potential of the micro-grid bidirectional converter, Q e And Q ref Output reactive power and output reactive power reference value respectively for micro-grid bidirectional converter, U e And U en Output port voltage and output port voltage rated value of micro-grid bidirectional converter respectively, D q Is a voltage regulation factor; e (E) 0 Representing the output potential of the micro-grid bi-directional converter in a steady state operating condition,
representing the disturbance quantity of the output potential of the micro-grid bidirectional converter, wherein delta is the power angle, delta 0 For the power angle in steady state operation +.>
As the power angle disturbance quantity, P e0 And Q e0 Active power and reactive power output by the micro-grid bidirectional converter under the steady state operation condition respectively are +.>
And->
The active power disturbance quantity and the reactive power disturbance quantity which are respectively output by the micro-grid bidirectional converter, P m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter m0 Virtual mechanical active power output by micro-grid bidirectional converter under steady state operation condition>
Representing virtual mechanical active power disturbance quantity output by a micro-grid bidirectional converter, wherein omega is actual angular velocity of a power grid 0 Synchronizing angular speed for grid +.>
U is the disturbance quantity of the actual angular velocity of the power grid e0 Output port voltage of micro-grid bidirectional converter under steady state operation condition +.>
The voltage disturbance quantity of the output port of the micro-grid bidirectional converter is obtained.
Eliminating the secondary component of the disturbance quantity and the steady-state quantity to obtain a small signal model of the output power of the micro-grid bidirectional converter:
wherein: x is equivalent output reactance of the micro-grid bi-directional converter, D is damping coefficient, J is rotational inertia of the synchronous generator, K i An integration coefficient of an integration link;
when calculating a small signal model of the output power of the micro-grid bidirectional converter, setting:
U e ＝E，sinδ 0 ＝δ 0 ，cosδ 0 ＝1；
2) The closed loop transfer function formula of the active power loop is calculated through a small signal model of the output power of the micro-grid bidirectional converter without considering the coupling of the active loop and the reactive loop, and is as follows:
wherein G(s) is the closed loop transfer function of the active power loop,
and->
The active power disturbance quantity output by the micro-grid bidirectional converter in the complex frequency domain and the virtual mechanical active power disturbance quantity output by the micro-grid bidirectional converter are respectively, X s The total output reactance of the micro-grid bidirectional converter after virtual impedance is introduced, and s represents the Laplacian operator; k is a proportionality constant, < >>
ω n And xi respectively represent the natural oscillation angular frequency and damping ratio of the closed loop transfer function of the active power loop, and are obtained by the following formula:
3) According to the closed loop transfer function of the active power loop and the AC subnet frequency formula, the open loop transfer function of the micro-grid bidirectional converter under the condition that the control target is the AC subnet frequency is obtained as follows:
wherein G is f (s) is the open loop transfer function of the micro-grid bidirectional converter control target at the frequency of the alternating current sub-grid, k f Is a frequency adjustment coefficient.
When the transmission power of the micro-grid bidirectional converter is negative, the active power transmitted by the micro-grid bidirectional converter is as follows:
wherein R is eq Is the equivalent resistance of a direct current sub-network, U dc Is the voltage of a direct current bus, P e1 The active power is output when the transmission power of the micro-grid bidirectional converter is negative, C is a direct-current side capacitor, and d is a differential operator. The active power/dc voltage transfer function considering small signal interference is expressed as follows:
wherein G is P-U (s) is an active power/direct current voltage transfer function when the transmission power of the micro-grid bi-directional converter is negative,
and->
The method is characterized in that the method is respectively the DC bus voltage disturbance quantity under the steady-state operation condition and the active power disturbance quantity output when the transmission power of the micro-grid bidirectional converter is negative.
According to the closed loop transfer function of the active power loop, the DC bus voltage formula and the active power/DC voltage transfer function when the transmission power of the micro-grid bidirectional converter is negative, the open loop transfer function under the condition that the control target of the micro-grid bidirectional converter is the DC bus voltage is obtained as follows:
wherein: g U (s) is the open loop transfer function of the control target of the micro-grid bidirectional converter under the voltage of a direct current bus, k pu And k pi The proportional and integral coefficients of the dc bus voltage PI regulator are shown, respectively.
4) And performing stability analysis according to the open loop transfer function of the micro-grid bidirectional converter under the control target of the AC subnet frequency and the DC bus voltage. The analysis includes:
according to the open loop transfer function of the micro-grid bidirectional converter with the control target of alternating current subnet frequency and direct current bus voltage, drawing parameters J, D, K by using a root locus method i When the closed loop transfer function pole is changed, the change track of the closed loop transfer function pole on the s plane is analyzed to obtain:
the larger the moment of inertia J is, the closer the pole of the closed loop transfer function is to the virtual axis, the more unstable the system is, the larger the moment of inertia is, the overshoot and the increase of the adjustment time can be caused, so that the power oscillation is caused, and the more unstable the system is; with the increase of the damping coefficient, the stability of the system is enhanced; along with the increase of the integral coefficient of the integral link, the closed loop pole is far away from the gradual real axis, the overshoot is increased, but the overshoot is always kept at the left side of the virtual axis, and the system stability is unchanged.
When the control target of the micro-grid bidirectional converter is direct current bus voltage, the open loop transfer function is composed of a proportional link, a first-order differential link, an integral link, a second-order oscillation link and a first-order inertia link. To keep the system stable and have good dynamic characteristics, the cut-off frequency f c Is positioned in a middle frequency band and satisfies k pi /k pu ＜f c ＜ω n 。
The micro-grid bidirectional converter control and stability analysis method based on the virtual synchronous machine realizes the non-deviation adjustment of the frequency of the micro-grid alternating current bus, proves the correctness of the micro-grid alternating current bus from theoretical deduction, increases the inertia of a micro-grid system, and can respond to the rapid fluctuation of the frequency of the system when the load fluctuates or fails. And the real-time switching of the alternating current frequency and direct current voltage control targets is realized by changing the virtual mechanical active power given mode in consideration of the bidirectional transmission characteristics of the converter.
Drawings
Fig. 1 is a control block diagram of a first example of a virtual synchronous machine-based micro-grid bi-directional converter control method of the present invention;
fig. 2 is a control block diagram of a second example of the virtual synchronous machine-based micro-grid bi-directional converter control method of the present invention;
FIG. 3 is a main circuit equivalent circuit in the present invention;
FIG. 4 is a small signal model of an active reactive power loop in the present invention;
FIG. 5 is a control block diagram in a frequency control mode in accordance with the present invention;
FIG. 6a is a plot of the pole change of the closed loop transfer function as the moment of inertia of the synchronous generator changes;
FIG. 6b is a plot of the pole change of the closed loop transfer function as the damping coefficient changes;
FIG. 6c is a plot of the pole change of the closed loop transfer function as the integration coefficient of the integration element changes;
FIG. 7 is a simplified diagram of a system in a DC bus voltage control mode in accordance with the present invention;
FIG. 8 is a control block diagram of the present invention in a DC bus voltage control mode;
FIG. 9 is a waveform of an alternating current frequency in a conventional VSG control and frequency control mode of the present method in accordance with an embodiment of the present invention;
FIG. 10 is a waveform of an AC bus voltage in a frequency control mode in an embodiment of the invention;
FIG. 11 is a waveform of DC bus voltage in DC bus voltage control mode in an embodiment of the invention;
fig. 12 is an ac frequency waveform in a dc bus voltage control mode according to an embodiment of the present invention.
Detailed Description
The method for controlling the micro-grid bidirectional converter and analyzing the stability based on the virtual synchronous machine is described in detail below with reference to the embodiment and the attached drawings.
In an AC/DC hybrid micro-grid, a micro-grid bidirectional converter coordinates power distribution of an AC sub-grid and a DC sub-grid and plays a role in maintaining the frequency of an AC bus and the voltage of a DC bus. The traditional virtual synchronous machine is used for controlling and simulating the steady-state sagging characteristic, transient inertia and damping of the synchronous generator, and has steady-state and electromechanical dynamic characteristics similar to those of the synchronous generator. However, in the off-grid operation mode of the micro-grid, the traditional virtual synchronous machine control has frequency deviation, and belongs to differential regulation;
when the load in the AC sub-network in the AC/DC hybrid micro-network suddenly increases to cause frequency fluctuation, each distributed power supply and the micro-network bidirectional converter adjust the respective output to maintain the power balance in the sub-network. In the control of the traditional virtual synchronous machine, the active frequency link can be adjusted only once when the load changes, and the frequency deviation can influence the normal operation of partial loads in the micro-grid. When the load suddenly increases, the mechanical power and the electromagnetic power deviate, and the motion equation of the synchronous generator rotor can be deformed into:
solving the first-order linear differential equation to obtain:
wherein K is i The integral coefficient of the integral link is J, the moment of inertia of the synchronous generator and omega 0 For the synchronous angular velocity of the power grid, ω is the actual angular velocity of the power grid, D is a differential operator, t is time, D is a damping coefficient, s is a Laplacian operator, ΔP is the difference between the virtual mechanical active power and the active power output by the micro-grid bidirectional converter, and C is a constant, and is determined by the initial condition of the state.
From the above analysis, the angular frequency after sudden load increase is composed of two parts, steady-state component
And transient component->
The transient component finally decays to zero with a decay time constant +.>
Therefore, under the control of the conventional VSG, the final steady-state value of the angular frequency is +.>
Belonging to differential regulation. The frequency offset is dependent on the power offset and the damping coefficient, and appropriate increases in the damping coefficient may reduce the steady-state frequency offset.
The invention relates to a micro-grid bidirectional converter control method based on a virtual synchronous machine, which is shown in figure 1, wherein an integration link is connected in parallel to a rotor motion equation damping link in the existing virtual synchronous machine control, and the integration link is that
Where s is Laplacian, K i The integration coefficient of the integration link is defined by +.>
Determining a value range, wherein xi represents the damping ratio of the closed loop transfer function of the active power loop, D represents a damping coefficient and X s Is the total output reactance of the micro-grid bidirectional converter after introducing virtual impedance, E 0 Representing output potential of micro-grid bidirectional converter under steady state operation condition, U e0 Output port voltage omega of micro-grid bidirectional converter under steady state operation condition 0 For grid synchronous angular velocity, J is the moment of inertia of the synchronous generator.
Thereby changing a rotor motion equation from a first-order equation to a second-order equation, wherein the rotor motion second-order equation is as follows:
wherein K is i The integral coefficient of the integral link is J, the moment of inertia of the synchronous generator and omega 0 For synchronous angular velocity of the power grid, ω is the actual angular velocity of the power grid, d is a differential operator, t is time, P m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter e And the active power output by the micro-grid bidirectional converter is represented, D is a damping coefficient, and s is a Laplacian operator.
The method is characterized by comprising the steps of arranging the above formula into a standard form of a second-order constant coefficient differential equation:
in order to keep the system running stably, parameters are set so that the solution of the standard form of the rotor motion equation meets the following form:
wherein: t is time, C 1 And C 2 An initial value, T, representing the angular frequency components 1 and 2 in the transient case 1 And T 2 Respectively represent decay time constants, ω, of angular frequency components 1 and 2 in the transient case * And (t) represents a steady state value after the attenuation of the angular frequency component in the transient state. When the load suddenly increases, the frequency is suddenly changed and tends to be stable. Solving the frequency expression under the steady state condition of the formula (5) is as follows:
therefore, under the micro-grid off-grid operation mode, the control of the micro-grid off-grid operation mode belongs to the indifferent adjustment through deducing a second-order synchronous generator rotor motion equation under the transient condition, and the unbiased control of the frequency under the micro-grid off-grid mode is realized.
And the real-time switching of the alternating current frequency and the direct current bus voltage control targets is realized by changing a given mode of the virtual mechanical active power reference value in consideration of the bidirectional transmission characteristics of the micro-grid bidirectional converter. The dc voltage control strategy in dc micro-grids generally employs active/voltage droop control, but has voltage deviation problems. The active controller shown in fig. 1 introduces frequency bias to calculate virtual machine active power and controls active power output by adjusting angular frequency. The analog of the non-deviation control of the frequency in the AC sub-network is that when the load fluctuation occurs in the DC sub-network, the control quantity is changed into the DC bus voltage, the voltage deviation is sent into the PI regulator to calculate the virtual mechanical active power, and the stable control of the DC bus voltage is realized. The invention sets that the power of the micro-grid bidirectional converter flows from the direct current sub-grid to the alternating current sub-grid to be positive.
As shown in fig. 2, the present invention changes the given mode of virtual machine active power in virtual synchronous machine control from unidirectional selection to bidirectional selection, specifically, when the ac subnet has power shortage, the transmission power of the micro-grid bidirectional converter is positive, and the control target is the ac subnet frequency; when the direct current sub-network has power shortage, the transmission power of the micro-network bidirectional converter is negative, and the control target is the direct current bus voltage. Wherein,,
the frequency formula of the alternating current sub-network is as follows:
P m ＝P ref +k f (f ref -f) (7)
wherein P is m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter ref And f ref Active power reference value and system frequency reference value, k respectively output by micro-grid bidirectional converter f Is a frequency adjustment coefficient;
the formula of the direct current bus voltage is as follows:
wherein U is dc Indicating the voltage of the DC bus, U dc_ref Represents the reference value, k, of the DC bus voltage pu And k pi The proportional and integral coefficients of the dc bus voltage PI regulator are shown, respectively.
The invention discloses a stability analysis method for micro-grid bidirectional converter control based on a virtual synchronous machine, which is used for carrying out stability analysis on the micro-grid bidirectional converter control method by establishing a small signal model of the output power of the micro-grid bidirectional converter, and specifically comprises the following steps:
step 1)
In FIG. 3, R e And L e Is the equivalent output resistance and reactance of the virtual synchronous machine, the equivalent output impedance of the virtual synchronous machineZ is:
Z＝R e +jωL e ≈jX (9)
the neutral point voltage phasor of the bridge arm of the micro-grid bidirectional converter is expressed as E < delta >, and the port voltage of the AC sub-grid is U e And (3) the angle 0, the active power and the reactive power output by the micro-grid bidirectional converter are as follows:
active power P output by rotor motion second-order equation and micro-grid bidirectional converter e And reactive power Q e Output potential equation of micro-grid bidirectional converter
The variables in (a) are expressed as the sum of the steady-state quantity and the disturbance quantity, i.e
Wherein K is q E represents the output potential of the micro-grid bidirectional converter, Q e And Q ref Output reactive power and output reactive power reference value respectively for micro-grid bidirectional converter, U e And U en Output port voltage and output port voltage rated value of micro-grid bidirectional converter respectively, D q Is a voltage regulation factor; e (E) 0 Representing the output potential of the micro-grid bi-directional converter in a steady state operating condition,
representing the disturbance quantity of the output potential of the micro-grid bidirectional converter, wherein delta is the power angle, delta 0 For the power angle in steady state operation +.>
As the power angle disturbance quantity, P e0 And Q e0 Respectively, the active power output by the micro-grid bidirectional converter under the steady state operation conditionPower and reactive power, +.>
And->
The active power disturbance quantity and the reactive power disturbance quantity which are respectively output by the micro-grid bidirectional converter, P m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter m0 Virtual mechanical active power output by micro-grid bidirectional converter under steady state operation condition>
Representing virtual mechanical active power disturbance quantity output by a micro-grid bidirectional converter, wherein omega is actual angular velocity of a power grid 0 Synchronizing angular speed for grid +.>
U is the disturbance quantity of the actual angular velocity of the power grid e0 Output port voltage of micro-grid bidirectional converter under steady state operation condition +.>
The voltage disturbance quantity of the output port of the micro-grid bidirectional converter is obtained.
Eliminating the secondary component of the disturbance quantity and the steady-state quantity to obtain a small signal model of the output power of the micro-grid bidirectional converter:
wherein: x is equivalent output reactance of the micro-grid bi-directional converter, D is damping coefficient, J is rotational inertia of the synchronous generator, K i An integration coefficient of an integration link;
when calculating a small signal model of the output power of the micro-grid bidirectional converter, setting:
U e ＝E，sinδ 0 ＝δ 0 ，cosδ 0 ＝1；
and carrying out Laplace transformation on the linearized equation to obtain a small signal model transfer block diagram of the active loop and the reactive loop, as shown in fig. 4.
As can be seen from FIG. 4, there is coupling between the active and reactive loops, but the coupling branch gains both contain delta 0 An item. Under the condition of normal operation of the micro-grid, the power angle value is very small. The invention realizes the approximate decoupling control of the active loop and the reactive loop by introducing a virtual impedance control algorithm. Synchronous generator potential E, output stator current I and terminal voltage U e The relationship is as follows:
wherein L is v Virtual inductance corresponding to virtual reactance, X s Is the converter output reactance after introducing the virtual impedance.
The virtual impedance is introduced to be equivalent to a virtual inductance connected in series with the output end of the converter, so that the output impedance of the converter is increased, the gain of a coupling branch is greatly reduced, and the approximate decoupling of an active loop and a reactive loop is realized.
2) The closed loop transfer function formula of the active power loop is calculated through a small signal model of the output power of the micro-grid bidirectional converter without considering the coupling of the active loop and the reactive loop, and is as follows:
wherein G(s) is the closed loop transfer function of the active power loop,
and->
The active power disturbance quantity output by the micro-grid bidirectional converter in the complex frequency domain and the virtual mechanical active power disturbance quantity output by the micro-grid bidirectional converter are respectively, X s Is micro-grid bidirectional current conversion after virtual impedance is introducedThe total output reactance of the device, s represents the Laplacian operator; k is a proportionality constant, < >>
ω n And xi respectively represent the natural oscillation angular frequency and damping ratio of the closed loop transfer function of the active power loop, and are obtained by the following formula:
3) According to the closed loop transfer function of the active power loop and the frequency formula of the alternating current sub-network, a control block diagram in the frequency control mode shown in fig. 5 can be obtained, and the open loop transfer function in the frequency control mode is obtained as follows:
under normal conditions, the direct current sub-network side operates stably according to the upper layer optimized power. Under transient conditions, the alternating current sub-network injects or absorbs active power into the direct current sub-network through the AC/DC bidirectional converter. To simplify the design, the DC sub-network can be equivalent to a constant resistance element R on the DC bus eq The resistance of the resistor depends on the active power injected into the DC sub-network side.
As can be seen from fig. 7, the active power transmitted by the converter is that when the active power loss in the converter is ignored
Wherein R is eq Is the equivalent resistance of a direct current sub-network, U dc Is the voltage of a direct current bus, P e1 The active power is output when the transmission power of the micro-grid bidirectional converter is negative, C is a direct-current side capacitor, and d is a differential operator. The active power/dc voltage transfer function considering small signal interference is as follows:
wherein G is P-U (s) is an active power/direct current voltage transfer function when the transmission power of the micro-grid bi-directional converter is negative,
and->
The method is characterized in that the method is respectively the DC bus voltage disturbance quantity under the steady-state operation condition and the active power disturbance quantity output when the transmission power of the micro-grid bidirectional converter is negative. According to the closed loop transfer function of the active power loop, the dc bus voltage formula and the active power/dc voltage transfer function when the transmission power of the micro-grid bidirectional converter is negative, the control block diagram in the frequency control mode shown in fig. 8 can be obtained, and the open loop transfer function in the dc bus voltage control mode is obtained as follows:
wherein: g U (s) is the open loop transfer function of the control target of the micro-grid bidirectional converter under the voltage of a direct current bus, k pu And k pi The proportional and integral coefficients of the dc bus voltage PI regulator are shown, respectively.
4) And performing stability analysis according to the open loop transfer function of the micro-grid bidirectional converter under the control target of the AC subnet frequency and the DC bus voltage. The analysis includes:
according to the open loop transfer function of the micro-grid bidirectional converter with the control target of alternating current subnet frequency and direct current bus voltage, drawing parameters J, D, K by using a root locus method i When the closed loop transfer function pole is changed, the change track of the closed loop transfer function pole on the s plane is analyzed to obtain:
as can be seen from fig. 6 (a), the larger the moment of inertia J, the closer the pole of the closed loop transfer function is to the virtual axis, the more unstable the system, the larger the moment of inertia will cause the overshoot and increase of the adjustment time, thereby causing power oscillation, and the more unstable the system will be; as can be seen from fig. 6 (b) (c), as the damping coefficient increases, the system stability increases; along with the increase of the integral coefficient of the integral link, the closed loop pole is far away from the gradual real axis, the overshoot is increased, but the overshoot is always kept at the left side of the virtual axis, and the system stability is unchanged.
When the control target of the micro-grid bidirectional converter is direct current bus voltage, the open loop transfer function is composed of a proportional link, a first-order differential link, an integral link, a second-order oscillation link and a first-order inertia link. To keep the system stable and have good dynamic characteristics, the cut-off frequency f c Is positioned in a middle frequency band and satisfies k pi /k pu ＜f c ＜ω n 。
Examples are given below:
the control method of the AC/DC hybrid micro-grid bidirectional converter based on the virtual synchronous machine is applied to the AC/DC hybrid micro-grid, and realizes the unbiased control of the AC frequency and the stable control of the DC bus voltage by means of the micro-grid bidirectional converter. Under normal conditions, the AC/DC hybrid micro-grid stably operates, and the transmission power of the micro-grid bidirectional converter is zero. When the alternating-current side load suddenly increases, the frequency is reduced, the control system detects the frequency deviation, a virtual mechanical active power signal is generated through operation and is sent to an inertial damping link, and the frequency deviation-free adjustment is realized through feedback compensation of an integration link. When the load suddenly increases at the DC side, the DC bus voltage is reduced, the system switches the control mode, and a virtual mechanical active power signal is generated through a DC voltage deviation signal, so that the stability of the DC bus voltage is maintained.
To verify the effectiveness of the invention, an ac/dc hybrid microgrid is established, wherein the ac bus voltage level is 380V (line voltage), the dc bus voltage is 800V, the microgrid bi-directional converter filtering device selects LC filters, wherein the circuit parameters are designed as inductance l=0.6h, capacitance c=20 μf, and the control circuit parameters are designed as moment of inertia j=2kg.m 2 Damping coefficient d=50, integral coefficient K i ＝1000。
When the micro-grid bidirectional converter is in off-grid operation, at the initial moment, the micro-grid bidirectional converter works in a frequency control mode, active power is transmitted to 80kW, and the system operates stably. The ac sub-network input load was 20kW at 0.5s and the cut-off load was 40kW at 1 s. Fig. 9 shows waveforms of frequency variation in the conventional VSG control and the frequency control mode of the present method. When the converter is controlled by a traditional virtual synchronous machine, the initial frequency is stabilized at 49.92Hz, the frequency is reduced and stabilized at 49.87Hz in 0.5s, the frequency is increased and stabilized at about 49.96Hz through slight overshoot in 1 s. When the frequency control mode is adopted, the initial frequency is stabilized at 50Hz, and the frequency can be quickly recovered and maintained at the rated frequency after the frequency is changed briefly at 0.5s and 1 s. By comparison, the frequency variation can be reduced, the inertial support is provided for the system, and the dynamic response is basically consistent. However, under the action of the frequency control mode, the method can realize the unbiased adjustment of the frequency. When the frequency deviation exceeds a threshold value, the frequency control mode of the method is adopted to enable the frequency of the micro-grid to be recovered to a rated value, and the frequency stability of independent operation of the system is improved. Fig. 10 shows the ac bus voltage amplitude waveform in the frequency control mode of the present method. When the load suddenly increases for 0.5s, the voltage amplitude of the alternating current bus is restored to be stable through short-term oscillation, and when the load suddenly decreases for 1s, the voltage amplitude is slightly reduced, but the voltage amplitude is always kept to be stable at about 311V.
When the micro-grid bidirectional converter works in a direct current bus voltage control mode, 180kW of active power is transmitted, and the control purpose of the converter is to keep the direct current bus voltage stable. Suppose that at 0.5s the dc sub-network load suddenly increases by 50kW. Fig. 11 shows a dc bus voltage waveform in the dc bus voltage control mode, and fig. 12 shows an ac bus frequency waveform in the dc bus voltage control mode. Initially the voltage stabilized at rated voltage 800V and at 0.5s the dc bus voltage dropped to around 780V and gradually recovered around the rated value. The direct current bus voltage control mode can keep the voltage of the direct current bus stable. When the load suddenly increases, the ac bus frequency slightly increases, but the frequency value is substantially stabilized at 50Hz.
Claims (4)
1. A control method of a micro-grid bidirectional converter based on a virtual synchronous machine is characterized in that an integration link is connected in parallel to a damping link of a rotor motion equation in the existing virtual synchronous machine control, and the rotor motion equation is changed from a first-order equation to a second-order equation, wherein the second-order equation is as follows:
wherein K is i The integral coefficient of the integral link is J, the moment of inertia of the synchronous generator and omega 0 For synchronous angular velocity of the power grid, ω is the actual angular velocity of the power grid, d is a differential operator, t is time, P m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter e The active power output by the micro-grid bidirectional converter is represented, D is a damping coefficient, and s is a Laplacian operator;
the integral link is
Where s is Laplacian, K i An integral coefficient of an integral link is formed by
Determining a value range, wherein xi represents the damping ratio of the closed loop transfer function of the active power loop, D represents a damping coefficient and X s Is the total output reactance of the micro-grid bidirectional converter after introducing virtual impedance, E 0 Representing output potential of micro-grid bidirectional converter under steady state operation condition, U e0 Output port voltage omega of micro-grid bidirectional converter under steady state operation condition 0 The synchronous angular speed of the power grid is obtained, and J is the rotational inertia of the synchronous generator;
changing a given mode of virtual mechanical active power in virtual synchronous machine control from unidirectional selection to bidirectional selection, specifically, when the AC sub-network has power shortage, the transmission power of the micro-network bidirectional converter is positive, and the control target is the AC sub-network frequency; when the direct current sub-network has power shortage, the transmission power of the micro-network bidirectional converter is negative, and the control target is the direct current bus voltage.
2. The method for controlling a micro-grid bi-directional converter based on a virtual synchronous machine according to claim 1, wherein the ac subnet frequency formula is as follows:
P m ＝P ref +k f (f ref -f)
wherein P is m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter ref And f ref Active power reference value and system frequency reference value, k respectively output by micro-grid bidirectional converter f Is a frequency adjustment coefficient;
the formula of the direct current bus voltage is as follows:
wherein U is dc Indicating the voltage of the DC bus, U dc_ref Represents the reference value, k, of the DC bus voltage pu And k pi The proportional and integral coefficients of the dc bus voltage PI regulator are shown, respectively.
3. The stability analysis method of the micro-grid bidirectional converter control method based on the virtual synchronous machine according to claim 1 is characterized in that the stability analysis is performed on the micro-grid bidirectional converter control method by establishing a small signal model of the output power of the micro-grid bidirectional converter, and the method is specifically as follows:
step 1) outputting active power P by a rotor motion second-order equation and a micro-grid bidirectional converter e And reactive power Q e Output potential equation of micro-grid bidirectional converter
The variables in (a) are expressed as the sum of the steady state quantity and the disturbance quantity, i.e.)>
Wherein K is q E represents the output potential of the micro-grid bidirectional converter, Q e And Q ref Output reactive power and output reactive power reference value respectively for micro-grid bidirectional converter, U e And U en Output port voltage and output port voltage rated value of micro-grid bidirectional converter respectively, D q Is a voltage regulation factor; e (E) 0 Representing the output potential of the micro-grid bi-directional converter in a steady state operating condition,
representing the disturbance quantity of the output potential of the micro-grid bidirectional converter, wherein delta is the power angle, delta 0 For the power angle in steady state operation +.>
As the power angle disturbance quantity, P e0 And Q e0 Active power and reactive power output by the micro-grid bidirectional converter under the steady state operation condition respectively are +.>
And->
The active power disturbance quantity and the reactive power disturbance quantity which are respectively output by the micro-grid bidirectional converter, P m Representing virtual mechanical active power, P, output by micro-grid bidirectional converter m0 Virtual mechanical active power output by micro-grid bidirectional converter under steady state operation condition>
Representing virtual mechanical active power disturbance quantity output by a micro-grid bidirectional converter, wherein omega is actual angular velocity of a power grid 0 Synchronizing angular speed for grid +.>
U is the disturbance quantity of the actual angular velocity of the power grid e0 Output port voltage of micro-grid bidirectional converter under steady state operation condition +.>
The voltage disturbance quantity of the output port of the micro-grid bidirectional converter is calculated;
eliminating the secondary component of the disturbance quantity and the steady-state quantity to obtain a small signal model of the output power of the micro-grid bidirectional converter:
wherein: x is equivalent output reactance of the micro-grid bi-directional converter, D is damping coefficient, J is rotational inertia of the synchronous generator, K i An integration coefficient of an integration link;
when calculating a small signal model of the output power of the micro-grid bidirectional converter, setting:
U e ＝E，sinδ 0 ＝δ 0 ，cosδ 0 ＝1；
step 2) irrespective of the coupling of the active loop and the reactive loop, the closed loop transfer function formula of the active power loop is calculated through a small signal model of the output power of the micro-grid bidirectional converter as follows:
wherein G(s) is the closed loop transfer function of the active power loop,
and->
The active power disturbance quantity output by the micro-grid bidirectional converter in the complex frequency domain and the virtual mechanical active power disturbance quantity output by the micro-grid bidirectional converter are respectively, X s Is micro-net bidirectional conversion after virtual impedance is introducedThe total output reactance of the streamer, s represents the Laplacian; k is a proportionality constant, < >>
ω n And xi respectively represent the natural oscillation angular frequency and damping ratio of the closed loop transfer function of the active power loop, and are obtained by the following formula:
step 3) according to a closed loop transfer function of an active power loop and an alternating current subnet frequency formula, obtaining an open loop transfer function of the micro-grid bidirectional converter under the condition that a control target is alternating current subnet frequency, wherein the open loop transfer function is expressed as follows:
wherein G is f (s) is the open loop transfer function of the micro-grid bidirectional converter control target at the frequency of the alternating current sub-grid, k f Is a frequency adjustment coefficient;
when the transmission power of the micro-grid bidirectional converter is negative, the active power transmitted by the micro-grid bidirectional converter is as follows:
wherein R is eq Is the equivalent resistance of a direct current sub-network, U dc Is the voltage of a direct current bus, P e1 The active power is output when the transmission power of the micro-grid bidirectional converter is negative, C is a direct-current side capacitor, and d is a differential operator; the active power/dc voltage transfer function considering small signal interference is expressed as follows:
wherein G is P-U (s) is an active power/direct current voltage transfer function when the transmission power of the micro-grid bi-directional converter is negative,
and->
The method is characterized in that the method comprises the steps of respectively outputting active power disturbance quantity under the condition of steady-state operation when the DC bus voltage disturbance quantity and the transmission power of the micro-grid bidirectional converter are negative, and U dc0 The DC bus voltage is the DC bus voltage under the steady-state operation condition;
according to the closed loop transfer function of the active power loop, the DC bus voltage formula and the active power/DC voltage transfer function when the transmission power of the micro-grid bidirectional converter is negative, the open loop transfer function under the condition that the control target of the micro-grid bidirectional converter is the DC bus voltage is obtained as follows:
wherein: g U (s) is the open loop transfer function of the control target of the micro-grid bidirectional converter under the voltage of a direct current bus, k pu And k pi Respectively representing the proportional coefficient and the integral coefficient of the direct current bus voltage PI regulator;
and 4) performing stability analysis according to the open loop transfer function of the micro-grid bidirectional converter under the conditions that the control target is the AC subnet frequency and the DC bus voltage.
4. A method for analyzing the stability of a virtual synchronous machine-based micro-grid bi-directional converter control method according to claim 3, wherein the analyzing in step 4) includes:
according to the open loop transfer function of the micro-grid bidirectional converter with the control target of alternating current subnet frequency and direct current bus voltage, drawing parameters J, D, K by using a root locus method i When changing, the change track of the pole of the closed loop transfer function on the s plane can be analyzedObtaining:
the larger the moment of inertia J is, the closer the pole of the closed loop transfer function is to the virtual axis, the more unstable the system is, the larger the moment of inertia is, the overshoot and the increase of the adjustment time can be caused, so that the power oscillation is caused, and the more unstable the system is; with the increase of the damping coefficient, the stability of the system is enhanced; along with the increase of the integral coefficient of the integral link, the closed loop pole is far away from the gradual real axis, the overshoot is increased, but the system stability is kept unchanged at the left side of the virtual axis all the time;
when the control target of the micro-grid bidirectional converter is direct current bus voltage, the open loop transfer function consists of a proportional link, a first-order differential link, an integral link, a second-order oscillation link and a first-order inertia link; to keep the system stable and have good dynamic characteristics, the cut-off frequency f c Is positioned in a middle frequency band and satisfies k pi /k pu ＜f c ＜ω n 。
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| CN111211573B (en) * | 2020-01-09 | 2021-03-30 | 中国科学院电工研究所 | Operation stability analysis method for AC/DC power distribution and utilization system |
| CN112039105A (en) * | 2020-07-22 | 2020-12-04 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Alternating current power grid frequency oscillation suppression method for high-voltage direct current transmission line interconnection |
| CN112398166B (en) * | 2020-11-09 | 2023-01-31 | 西安热工研究院有限公司 | Parameter analysis method for energy storage primary frequency modulation virtual synchronous machine |
| CN112467786B (en) * | 2020-11-18 | 2023-01-31 | 西安热工研究院有限公司 | Small signal model analysis method for virtual synchronous machine of hybrid microgrid converter |
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| CN112769138A (en) * | 2020-12-31 | 2021-05-07 | 北京四方继保自动化股份有限公司 | AC-DC mutual aid control device and method for AC-DC hybrid power distribution network junction converter |
| CN112865062B (en) * | 2021-01-11 | 2022-11-25 | 河海大学 | Direct-current micro-grid damping enhancement control method considering multi-type load access |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108832657A (en) * | 2018-06-22 | 2018-11-16 | 太原理工大学 | Alternating current-direct current mixing micro-capacitance sensor bidirectional power converter virtual synchronous motor control method |
| CN108923460A (en) * | 2018-07-10 | 2018-11-30 | 华北电力大学（保定） | The method for parameter configuration that microgrid virtual synchronous machine multi-machine parallel connection dynamic unanimously responds |
| CN109861246A (en) * | 2018-12-24 | 2019-06-07 | 燕山大学 | A kind of photovoltaic microgrid dynamic frequency stable control method based on VSG |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106208159B (en) * | 2016-07-27 | 2018-09-18 | 合肥工业大学 | Bavin storage mixing independent micro-grid dynamic power compensation method based on virtual synchronous generator |
| CN106410849B (en) * | 2016-11-10 | 2019-01-15 | 合肥工业大学 | Microgrid inverter balance control method based on virtual synchronous generator |
| CN106786780B (en) * | 2017-03-02 | 2019-08-27 | 江苏大学 | A kind of grid-connected control method and system based on virtual synchronous generator |
| CN107104439B (en) * | 2017-05-17 | 2020-03-24 | 东北大学 | Hybrid micro-grid system with multiple direct-current subnetworks and control method |
| CN107294124B (en) * | 2017-07-17 | 2020-06-26 | 中国科学院电工研究所 | Novel virtual synchronous generator control method suitable for energy storage system |
| CN107863786B (en) * | 2017-11-22 | 2021-03-26 | 太原理工大学 | Bidirectional power converter control method based on virtual synchronous motor |
| CN107994620A (en) * | 2017-12-28 | 2018-05-04 | 东南大学 | Flexible ring net controller both-end virtual motor control method |
| CN108418256B (en) * | 2018-03-13 | 2021-01-15 | 西安理工大学 | Virtual synchronous machine self-adaptive control method based on output differential feedback |
| CN108493997A (en) * | 2018-04-13 | 2018-09-04 | 哈尔滨理工大学 | Rotary inertia optimal control method based on virtual synchronous generator |
| CN108964117A (en) * | 2018-06-13 | 2018-12-07 | 西安理工大学 | A kind of control method of the virtual synchronous generator with unbalanced load and its parallel connection |
| CN109842157B (en) * | 2019-03-21 | 2022-07-29 | 东北大学 | Microgrid inverter control method based on improved virtual synchronous generator |
-
2019
- 2019-06-14 CN CN201910514536.8A patent/CN110198055B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108832657A (en) * | 2018-06-22 | 2018-11-16 | 太原理工大学 | Alternating current-direct current mixing micro-capacitance sensor bidirectional power converter virtual synchronous motor control method |
| CN108923460A (en) * | 2018-07-10 | 2018-11-30 | 华北电力大学（保定） | The method for parameter configuration that microgrid virtual synchronous machine multi-machine parallel connection dynamic unanimously responds |
| CN109861246A (en) * | 2018-12-24 | 2019-06-07 | 燕山大学 | A kind of photovoltaic microgrid dynamic frequency stable control method based on VSG |
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