CN116316848A - Virtual synchronous generator and virtual synchronous motor-based direct-drive fan cooperative control system and method in micro-grid - Google Patents
Virtual synchronous generator and virtual synchronous motor-based direct-drive fan cooperative control system and method in micro-grid Download PDFInfo
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- H—ELECTRICITY
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Abstract
The invention discloses a direct-driven fan cooperative control system and method in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor, comprising a voltage-current double-loop control algorithm, a virtual synchronous motor control and a virtual synchronous generator control, wherein the voltage loop adopts proportional control to accelerate the response speed of the system, and the current loop adopts a proportional integral regulator to inhibit the harmonic component of output voltage; and a virtual synchronous motor is adopted to control at the fan side, so that power is absorbed and input into a direct current bus. The main function is to control the voltage stabilization of the direct current bus and to control the power factor of the alternating current side of the fan to be 1 so as to reduce the loss, and the converter feeds active power and reactive power into the power grid at the power grid side. The invention ensures the balance of the output three-phase voltage on the basis of not changing the structure of the VSG algorithm, and is suitable for the working condition of output power oscillation caused by the condition of low short-circuit ratio of a long-distance transmission line when the VSG is in grid-connected operation.
Description
Technical Field
The invention relates to a control method of a three-phase power electronic inverter, in particular to a direct-drive fan cooperative control system in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor.
Background
As a main form of future renewable energy source application, the distributed power source has the advantages of less pollution, high reliability, high energy utilization rate, flexible installation site and the like. The installed capacities of thermal power and hydropower in China are obviously increased, and the installed capacities of grid-connected wind power generation and solar power generation are rapidly increased. Unfortunately with the rapid growth of wind power generation, weaker wind farms are interconnected in some grids. For example, in the western part of china. Such oscillations will lead to torsional interactions with synchronous generators which will seriously affect economy, production and life. In the background of more and more distributed power supply access, how to realize friendly access of the distributed power supply and reduce the influence of oscillation on a power grid during grid connection have become research hot spots in the current distributed energy direction. The virtual synchronous generator technology is an inverter control technology provided under the background, combines the flexibility of power electronic equipment and the operation mechanism of a synchronous generator, can effectively solve the problems of underdamping and low inertia of a system caused by high permeability of a distributed power supply, promotes coordination of the power supply and load, and has wide application prospect.
However, the VSG referenced from the synchronous motor will also have all the advantages and disadvantages of the synchronous motor, such as the possibility of occurrence of adverse phenomena in the synchronous inverter; stability loss due to under-excitation and oscillation; when the VSG is in grid-connected operation, given power change and power grid frequency fluctuation often occur, and the phenomenon of overshoot or lack of output power is extremely easy to cause. Recently, a direct-drive permanent magnet fan power plant located in the Sinkiang Uygur autonomous region of China detects continuous sub-synchronous frequency oscillation. This new oscillation has never been reported and analyzed in an actual system before it was detected in the actual field. Therefore, the mechanism and characteristics thereof are not yet clear. The invention provides a control strategy capable of effectively suppressing oscillation problems at sub-synchronous frequencies.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a direct-drive fan cooperative control system in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor, wherein the structure of a VSG control algorithm is not changed, and a voltage and current double-loop control algorithm based on feedforward virtual impedance is adopted as a bottom control algorithm of the VSG to modulate the output three-phase voltage of the VSG; and a VSG-VSM cooperative control method is adopted, so that the requirements of frequency stability and stability during grid connection are ensured.
The technical scheme for solving the technical problems is as follows: a direct-drive fan cooperative control method in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor comprises the following steps:
s1: selecting a proper control mode according to given power and voltage on the fan side and the power grid side, wherein the fan side operates under the VSM, and operates under the VSG when grid connection is performed;
s2: subtracting the given power from the active power output by the VSG, converting the active power and the given power into virtual torque, simulating mechanical torque and electromagnetic torque in the motor, and compensating the difference value between the direct-current side voltage and the output voltage of the VSG through a voltage compensation transfer function;
s3: adding VSG to output three-phase voltage to the active loop control, and realizing frequency droop control through a droop coefficient Dp; adding three-phase current output by VSG into the reactive ring, and obtaining exciting current if through VSG reactive regulation, so that reactive power can be controlled;
s4: adding virtual impedance into the front end of a voltage current loop, carrying out FFT analysis on grid-connected current to obtain a frequency component of oscillating current, and then reducing the impact of the oscillating current by changing the value of the virtual impedance;
s5: through balancing the voltage current dq axis, proper values of rotational inertia J and voltage coefficient K are selected, cdq which is subjected to voltage current double-loop modulation is obtained, PWM pulse signals are obtained through PWM to generate PWM pulse signals to drive IGBT semiconductor devices, and oscillation impact of grid-connected voltage can be effectively reduced.
Further, the virtual torque described in S2 simulates mechanical torque and electromagnetic rotation in the motor, thereby implementing a simulated synchronous generator, providing inertia and damping to the power grid.
Further, in S3, the angular frequency is output by the VSG through the phase-locked loop, the angular frequency of the output of the VSG is subtracted from the actual angular frequency, and then frequency control during grid connection is achieved through the damping coefficient Dq, so that the exciting current if simulates the exciting current of the rotor of the synchronous motor, and reactive power is controlled.
Further, a virtual impedance is introduced in S4, and the frequency component of the oscillating current is suppressed by performing FFT analysis on the grid-connected current and then changing the value of the virtual impedance, so as to reduce the surge of the oscillating current.
Further, in S5, proper moment of inertia J and voltage coefficient K are selected, the two are subjected to bode diagram analysis, the influence of different values is selected, and the setting of the value ranges of the two is realized.
The invention discloses a direct-drive fan cooperative control system in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor, which is characterized by comprising the following components: the device comprises a direct-drive fan, a micro-grid, a three-phase full-bridge inverter, a filter, an alternating-current grid, a VSG control algorithm module, a VSM control algorithm module, a double-loop control module and a virtual impedance module; the main circuit is connected with an AD/DC converter by a direct-drive fan, the AC/DC converter is connected with a three-phase full-bridge inverter, the three-phase full-bridge inverter is connected with a filter, and the filtered power is connected with a micro-grid consisting of an alternating-current grid; the control circuit controls the fan side by the VSM control algorithm module, the VSG control algorithm module controls the power grid side, the output of the VSG control algorithm module is connected with the virtual impedance module, and the virtual impedance module is used as a feedforward connection double-loop control module;
the VSG control algorithm module mainly comprises active power control and reactive power control:
wherein E is the output voltage; u is the terminal voltage; delta is the power angle of the virtual synchronous generator; s delta = ω, ω being the reference angular frequency of the VSG; z and theta 1 Impedance and impedance angle, Z and θ, respectively, of the virtual synchronous generator filter circuit 1 The expression of (2) is:
wherein L is a filter inductor; r is a resistor;
the VSM control algorithm module mainly consists of electromagnetic torque T e The reactive power Q and the synthesized voltage e are controlled to be composed, and the formulas are respectively as follows:
wherein: m is M f The maximum mutual inductance between the exciting winding and the three-phase stator coil is achieved; i.e f The exciting current of the rotor is represented by θ, the generator angle of the machine side is represented by i, and the motor current is represented by i;
the double-loop control module is used for generating modulation waves under the dq axis, and the formula is as follows:
wherein: g i (s) is a voltage compensation link; i.e dref 、i Ld For a current setpoint and a sampling current; k (K) d Is a modulation factor;
the virtual impedance module formula is as follows:
wherein: r is R v Is a virtual resistor; x is x d 、x q D and q axes virtual reactance respectively; i d ，I q D, q-axis current;
U dref ，U qref reference voltages for d and q axes; e (E) q ' is the q-axis component of the output voltage.
The VSG control algorithm module comprises a voltage and current analog signal sampling module, an AD conversion module, an instantaneous power calculation module, an active control loop, a reactive control loop and a modulation wave synthesis module; the voltage and current analog signal sampling module samples the output voltage and current of the inverter, and the sampled voltage and current are connected with the AD conversion module, converted into digital quantity and then connected with the instantaneous power meterThe calculation module calculates active power and reactive power, the calculated values of the active power and the reactive power are respectively connected with the active control loop and the reactive control loop, and the output voltage E is obtained by a control algorithm m And the phase angle theta is connected to a modulation synthesis module, and finally a three-phase voltage modulation wave signal is obtained.
Further, the VSM control algorithm module is used as a bottom layer control module of the direct-drive fan to cooperatively control with the VSG control algorithm module, controls the voltage stabilization of the direct-current bus, absorbs power and inputs the power to the direct-current bus, and then inputs the active and reactive stabilities to a power grid.
Further, the virtual impedance module is combined with the VSG control algorithm and the double-loop control module, adds virtual impedance into the front end of double-loop control, processes the three-phase voltage modulation wave signal, suppresses the frequency component of the oscillation current of the output end, and reduces the impact of grid-connected voltage and current.
Compared with the prior art, the control method provided by the invention has the following beneficial effects:
1. the invention adopts a voltage and current double-loop control algorithm, is suitable for bottom control of most common inverter control algorithms, and ensures the rapidity and accuracy of system response. For the main circuit, the cooperative control of VSG-VSM is adopted, and the droop control of frequency and voltage is realized by simulating the moment of inertia and the droop coefficient of the synchronous motor.
2. The method provided by the invention is used for focusing on solving the problem that a long-distance transmission line causes low short-circuit ratio, presents capacitance characteristic and is mutually coupled with power grid inductance, and particularly for a VSG grid-connected system, the problem of power oscillation is caused during grid connection, and various oscillations in the system can be well restrained by adopting feedforward virtual impedance control and selecting a proper virtual resistance value.
3. The method provided by the invention analyzes the influence of the moment of inertia J and the damping coefficient K on the stability of the system. Aiming at the influence of the system stability, the value of the system is controlled in intervals, and the influence of J and K on the system is comprehensively considered.
Drawings
FIG. 1 is a diagram of a DC micro-grid structure with a direct-drive fan according to the present invention;
FIG. 2 is a control block diagram of a machine-to-network side virtual synchronous machine according to the present invention;
FIG. 3 is a dynamic virtual impedance control block diagram of the present invention;
FIG. 4 shows the output impedance of the VSG of the present invention
Detailed Description
The principles and features of the present invention are described below with reference to the drawings, the examples are illustrated for the purpose of illustrating the invention and are not to be construed as limiting the scope of the invention.
The technical scheme of the invention is described in detail below with reference to the accompanying drawings.
Conventional SGs regulate the active output of the generator by regulating the mechanical torque and achieve a response to grid frequency deviations by means of a frequency regulator. Based on this principle, the adjustment of the active command of the grid-connected inverter is achieved by adjusting the virtual mechanical torque Tm of the VSG. The prime motor regulation and the rotor motion equation jointly form a power frequency regulator. The prime mover of the synchronous generator is adjusted as follows:
Q set +D q (V 0 -V)-Q e ＝K s E m (12)
wherein ω is angular frequency; omega 0 Is the synchronous angular velocity of the power grid; k (K) s Is the frequency modulation factor. T (T) m 、T e And T d Mechanical torque, electromagnetic torque and damping torque, respectively; v (V) 0 、V、E m Respectively an output voltage, a nominal voltage and an output voltage. D (D) p And D q The droop coefficients of the frequency active power and reactive voltage, respectively, J being the moment of inertia.
According to different wind speeds, it is generally possible to divide into 4 regions: a starting area, a maximum power tracking area (low wind speed area), a rotating speed constant area (medium wind speed area) and a power constant area (high wind speed area). In a low wind speed region and a medium wind speed region, the wind turbine generator sets carry out maximum wind power tracking control or rotating speed control; in a high wind speed region, the wind turbine generator keeps the power constant by adjusting the pitch angle.
The direct current micro-grid containing distributed energy sources is low in inertia, busbar voltage is easily affected by load power fluctuation, a large amount of kinetic energy is contained in the rotor of the wind turbine generator, the control strategy of the fan-side converter can be changed, the generator rotor can release or store the kinetic energy, and inertial support is provided for the direct current voltage. When VSG is in grid-connected operation, the line impedance is capacitive under the influence of a long-distance transmission line, so that the conditions of power oscillation and power grid frequency fluctuation are caused, the working condition of overshoot or lack of output power is extremely easy to cause, the operation condition of stable output in a micro-grid cannot be met, and the relevant regulation of stable operation of a power system cannot be met. The invention provides a direct-drive fan cooperative control method and system in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor, which aim to improve the output voltage quality of the micro-grid and enhance the frequency stability of the system.
A block diagram of a distributed inverter power system under the control of the VSG algorithm is shown in fig. 1, and the distributed inverter power system includes: the direct-drive fan, the three-phase inverter bridge formed by S1-S6, a fan side inductor L, a direct-current side capacitor C, a direct-current load and a power grid. The VSM-VSG control module is shown in fig. 2, and consists of an electromagnetic torque calculation module, a reactive power calculation module, an active control loop, a reactive control loop and a phase-locked loop, wherein a sensor is used for measuring the instantaneous quantity of three-phase voltage and current output by a load public end, calculating instantaneous power and giving VSG power, a VSG output voltage signal is obtained through a VSG active loop, a reactive loop and a three-phase voltage signal synthesis module, the signal is processed through a double-loop control module, and finally a PWM signal is generated through a SVPWM module to control the action of an inverter switching tube. The cooperative control method specifically comprises the following steps:
the step 1, the P/Q control can realize the constant power output of the distributed generator, which consists of a power outer ring and a current inner ring, and the control mode is widely applied to grid-connected VSG units. When P/Q control is applied in grid-tie mode, the active power may be well compliant with the governor's dispatch commands.
The fan system is connected to the power grid through a back-to-back power electronic converter, which is typically used to control the maximum power output, and a grid-side converter is used to control the dc bus voltage. At present, since the coupling term in the decoupling process is related to the system parameter, the vector control method is sensitive to the change of the system parameter of the permanent magnet synchronous generator. The virtual synchronous machine control algorithm can be well applied to back-to-back converters. The fan-side converter absorbs power from the permanent magnet synchronous motor and inputs power to the dc bus, and thus can operate in a Virtual Synchronous Motor (VSM) mode. The main task of the fan-side converter is to control the dc bus voltage and to control the power factor on the ac side of the fan to 1 to reduce losses. Unlike vector control, the synchronous converter control strategy does not depend on parameters of the permanent magnet synchronous motor, so that the system performance can be improved well.
And 2, a phase-locked loop adopted by the motor test control of the direct-driven wind turbine generator is a static coordinate system phase-locked loop. The voltage reference is provided by a dc-link voltage regulator. The transfer functions of the voltage and current compensators are given by the following formula, wherein the regulator adopts a PI controller and an integrator, and the transfer functions are as follows:
wherein K is p 、k p The scaling coefficients of the voltage compensator and the current compensator, respectively; k (K) i 、k i Is the integral coefficient of the voltage and current compensators.
In the current power system, the power grid frequency and the voltage are controlled by adjusting active power and reactive power respectively, and common control methods are frequency droop control and voltage droop control. Due to coefficient D p Has the functions of frequency droop and damping, thus D can be utilized p Directly realize frequency droop without adding extraIs a control link of the system. The frequency loop may control the angular frequency of the synchronous inverter and generate the phase angle of the back emf e. Active power command P due to relatively small frequency variations in the power system set Can be directly converted into corresponding mechanical torque T m . Correspondingly, the exciting current M f i f Can be controlled by controlling the reactive power. To achieve voltage sag control, the difference in terminal voltage relative to nominal voltage may be controlled by a voltage sag factor D q Amplified and then added to reactive power command Q set And (3) upper part.
And 4, the virtual impedance technology can change the output impedance characteristic of the inverter and reduce the difference between VSG and the output impedance characteristic of the fan. In order to ensure that the voltage reference value does not change suddenly when the operation mode is switched, virtual impedance in the two modes is still required to be equal on the basis that the phase and the internal potential amplitude are consistent. A large virtual impedance may deteriorate the dynamics of the VSG when operating independently. Therefore, it is proposed to employ a dynamic virtual impedance algorithm.
Port phase voltage of motor:
wherein: r is R s 、L s The total resistance and inductance of the resistor. e is modeled as the back electromotive force generated by the rotor motion in the stator windings:
e＝θM f i f sinθ (16)
wherein: m is M f The maximum mutual inductance between the exciting winding and the three-phase stator coil is achieved; i.e f Which is the excitation current of the rotor.
The VSG virtual impedance design calculation is:
wherein: r is R v Is a virtual resistor; x is x d 、x q D and q axes virtual reactance respectively; i d ，I q For d, q-axis current；U dref ，U qref Is the reference voltage of d and q axes. E (E) q ' is the q-axis component of the output voltage. The dynamic virtual impedance design method is shown in fig. 3, and the set values in the two modes are kept consistent; d. the q-axis virtual reactance is composed of a constant term and a dynamic variation amount, respectively.
Wherein the constant term X dc 、X qc Is a virtual reactance at steady state for improved subnet power allocation. Introducing dynamic variation X under oscillation working condition dv 、X qv Virtual exciting current amplitude variation delta I by VSG f Judging the occurrence of load abrupt change working condition when |delta I f When the I exceeds the set threshold epsilon, judging the oscillation working condition, and multiplying the absolute value of the part exceeding the threshold by a proportional coefficient K d 、K q Obtaining dynamic variation of virtual impedance, wherein the expression is as follows:
and 5, when the output impedance of the wind power inverter is modeled, the direct current bus voltage is assumed to be constant, so that the dynamics of the voltage control loop and the turbine rectifier can be ignored. The resulting turbine inverter output impedance model is shown below. The output impedance of the inverter is established, including the ac inductor, but not the LC filter:
wherein: k (K) m 、K d 、K f Are all modulation coefficients, V 1 、I 1 Is an inverterOutput voltage and current of T 1 ＝{j2πf 1 L 1 +V 1 [1-K m V dc K f ]}/(K m V dc )，L 1 ，L f Is a filter inductance; v (V) dc Is a direct current side voltage; f (f) 1 Is the reference frequency; h i (s)、G i (s) is a current and voltage compensation function; t (T) PLL (s) is a transfer function of a phase locked loop: t (T) PLL ＝V 1 H i /(1+V 1 H i )；
Is the power factor angle.
FIG. 4 is a Bode plot of the positive sequence impedance of VSG for moment of inertia J and sag factor D, respectively p Expanding and contracting by 10 times, comparing to find that J has great influence on the phase margin, and the selection range of J is not large for the low-frequency end and considering the stability margin. Sag factor D p Mainly affects impedance characteristics near fundamental frequency, sag factor D p The larger the VSG will be, the closer the capacitive characteristic.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.
Claims (9)
1. A direct-drive fan cooperative control method in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor is characterized by comprising the following steps:
s1: selecting a proper control mode according to given power and voltage on the fan side and the power grid side, wherein the fan side operates under the VSM, and operates under the VSG when grid connection is performed;
s2: subtracting the given power from the active power output by the VSG, converting the active power and the given power into virtual torque, simulating mechanical torque and electromagnetic torque in the motor, and compensating the difference value between the direct-current side voltage and the output voltage of the VSG through a voltage compensation transfer function;
s3: adding VSG to output three-phase voltage to the active loop control, and realizing frequency droop control through a droop coefficient Dp; adding three-phase current output by VSG into the reactive ring, and obtaining exciting current if through VSG reactive regulation, so that reactive power can be controlled;
s4: adding virtual impedance into the front end of a voltage current loop, carrying out FFT analysis on grid-connected current to obtain a frequency component of oscillating current, and then reducing the impact of the oscillating current by changing the value of the virtual impedance;
s5: through balancing the voltage current dq axis, proper values of rotational inertia J and voltage coefficient K are selected, cdq which is subjected to voltage current double-loop modulation is obtained, PWM pulse signals are obtained through PWM to generate PWM pulse signals to drive IGBT semiconductor devices, and oscillation impact of grid-connected voltage can be effectively reduced.
2. The method for cooperatively controlling the direct-drive fan in the micro-grid based on the virtual synchronous generator and the virtual synchronous motor according to claim 1, wherein the virtual torque in the step S2 simulates the mechanical torque and the electromagnetic rotation in the motor, so that the simulated synchronous generator is realized, and inertia and damping are provided for the grid.
3. The method for cooperatively controlling the direct-drive fans in the micro-grid based on the virtual synchronous generator and the virtual synchronous motor according to claim 1, wherein the angular frequency in the S3 is outputted by the VSG through the phase-locked loop, the outputted angular frequency of the VSG is subtracted from the actual angular frequency, and then the frequency control during grid connection is realized through the damping coefficient Dq, the exciting current if simulates the exciting current of a rotor of the synchronous motor, and the reactive power is controlled.
4. The method for collaborative control of direct-drive fans in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor according to claim 1, wherein virtual impedance is introduced in S4, and the frequency component of the oscillating current is suppressed by performing FFT analysis on the grid-connected current and then changing the value of the virtual impedance, so as to reduce the impact of the oscillating current.
5. The method for collaborative control of direct-drive fans in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor according to claim 1 is characterized in that in S5, proper moment of inertia J and voltage coefficient K are selected, bote diagram analysis is carried out on the moment of inertia J and the voltage coefficient K, influences of different values are selected, and setting of the value ranges of the moment of inertia J and the voltage coefficient K is achieved.
6. A direct-drive fan cooperative control system in a micro-grid based on a virtual synchronous generator and a virtual synchronous motor is characterized by comprising the following components:
the device comprises a direct-drive fan, a micro-grid, a three-phase full-bridge inverter, a filter, an alternating-current grid, a VSG control algorithm module, a VSM control algorithm module, a double-loop control module and a virtual impedance module;
the main circuit is connected with an AD/DC converter by a direct-drive fan, the AC/DC converter is connected with a three-phase full-bridge inverter, the three-phase full-bridge inverter is connected with a filter, and the filtered power is connected with a micro-grid consisting of an alternating-current grid; the control circuit controls the fan side by the VSM control algorithm module, the VSG control algorithm module controls the power grid side, the output of the VSG control algorithm module is connected with the virtual impedance module, and the virtual impedance module is used as a feedforward connection double-loop control module;
the VSG control algorithm module mainly comprises active power control and reactive power control:
wherein E is the output voltage; u is the terminal voltage; delta is the power angle of the virtual synchronous generator; s delta = ω, ω being the reference angular frequency of the VSG; z and theta 1 Impedance and impedance angle, Z and θ, respectively, of the virtual synchronous generator filter circuit 1 The expression of (2) is:
wherein L is a filter inductor; r is a resistor;
the VSM control algorithm module mainly consists of electromagnetic torque T e The reactive power Q and the synthesized voltage e are controlled to be composed, and the formulas are respectively as follows:
wherein: m is M f The maximum mutual inductance between the exciting winding and the three-phase stator coil is achieved; i.e f The exciting current of the rotor is represented by θ, the generator angle of the machine side is represented by i, and the motor current is represented by i;
the double-loop control module is used for generating modulation waves under the dq axis, and the formula is as follows:
wherein: g i (s) is a voltage compensation link; i.e dref 、i Ld For a current setpoint and a sampling current; k (K) d Is a modulation factor;
the virtual impedance module formula is as follows:
wherein: r is R v Is a virtual resistor; x is x d 、x q D and q axes virtual reactance respectively; i d ，I q D, q-axis current; u (U) dref ，U qref Reference voltages for d and q axes; e (E) q ’ Is the q-axis component of the output voltage.
7. The system of claim 6, wherein the VSG control algorithm module comprises a voltage, current analog signal sampling module, an AD conversion module, an instantaneous power calculation module, an active control loop, a reactive control loop, a modulated wave synthesis module; wherein the voltage and current analog signalsThe number sampling module samples the output voltage and current of the inverter, the sampled voltage and current are connected with the AD conversion module, are converted into digital quantity and are connected with the instantaneous power calculation module, the active power and the reactive power are calculated, the calculated values of the active power and the reactive power are respectively connected with the active control loop and the reactive control loop, and the output voltage E is obtained by a control algorithm m And the phase angle theta is connected to a modulation synthesis module, and finally a three-phase voltage modulation wave signal is obtained.
8. The system of claim 6, wherein the VSM control algorithm module, acting as a bottom layer control module for the direct drive fan, is cooperatively controlled with the VSG control algorithm module to control the dc bus voltage stabilization, absorb power and input power to the dc bus, and then input active and reactive stabilities to the power grid.
9. The system of claim 6, wherein the virtual impedance module, in combination with the VSG control algorithm and the dual-loop control module, adds virtual impedance to the front end of the dual-loop control, processes the three-phase voltage modulated wave signal, suppresses the frequency component of the oscillating current at the output end, and reduces the impact of the grid-connected voltage and current.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116961509A (en) * | 2023-07-25 | 2023-10-27 | 哈尔滨工业大学 | Single-current loop control method of current source inverter for permanent magnet synchronous motor |
| CN117039935A (en) * | 2023-08-23 | 2023-11-10 | 昆明理工大学 | Method for cooperatively controlling multi-state objects of micro-grid system by utilizing VSG |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116961509A (en) * | 2023-07-25 | 2023-10-27 | 哈尔滨工业大学 | Single-current loop control method of current source inverter for permanent magnet synchronous motor |
| CN116961509B (en) * | 2023-07-25 | 2024-06-07 | 哈尔滨工业大学 | Single-current loop control method of current source inverter for permanent magnet synchronous motor |
| CN117039935A (en) * | 2023-08-23 | 2023-11-10 | 昆明理工大学 | Method for cooperatively controlling multi-state objects of micro-grid system by utilizing VSG |
| CN117039935B (en) * | 2023-08-23 | 2024-04-30 | 昆明理工大学 | Method for cooperatively controlling multi-state objects of micro-grid system by utilizing VSG |
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