CN112346439B - Micro-grid sensor fault tolerance control method based on PD type learning observer - Google Patents

Micro-grid sensor fault tolerance control method based on PD type learning observer Download PDF

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CN112346439B
CN112346439B CN202011309721.2A CN202011309721A CN112346439B CN 112346439 B CN112346439 B CN 112346439B CN 202011309721 A CN202011309721 A CN 202011309721A CN 112346439 B CN112346439 B CN 112346439B
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CN112346439A (en
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茅靖峰
周翔
李鹏
吴爱华
张旭东
张雷
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Nantong University
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    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B23/00Testing or monitoring of control systems or parts thereof
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    • G05B23/0259Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterized by the response to fault detection
    • G05B23/0262Confirmation of fault detection, e.g. extra checks to confirm that a failure has indeed occurred
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
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Abstract

The invention belongs to the technical field of microgrid fault tolerance control, and particularly relates to a microgrid sensor fault tolerance control method based on a PD type learning observer. The method comprises the following steps: step 1, establishing a system closed-loop output feedback controller according to a state space model of a micro-grid inverter type distributed power supply; step 2, establishing a sensor fault model of the microgrid system, and converting the sensor fault model into an actuator fault model form; and 3, establishing a sensor fault-tolerant PD type learning observer, solving a reconstructed fault signal, feeding back an output compensated by the reconstructed signal to an output feedback controller, and ensuring the stable tracking of the output power. Real-time monitoring of faults is realized, the faults of the sensors are accurately reconstructed, and measurement errors of the sensors are corrected by using the reconstructed fault signals; the IIDG can run safely and reliably when grid-connected power of the micro-grid system is transmitted, and the method has wide adaptability to various faults of the micro-grid sensor.

Description

Micro-grid sensor fault tolerance control method based on PD type learning observer
Technical Field
The invention belongs to the technical field of microgrid fault tolerance control, and particularly relates to a microgrid sensor fault tolerance control method based on a PD type learning observer.
Background
In recent years, distributed power generation technology based on renewable energy has been widely used due to shortage of fossil energy and increasing environmental problems. However, the distributed power supplies have inherent defects of high output power randomness, high regulation difficulty and the like, so that the safe and stable operation of the power system is influenced to a certain extent by the access of a large number of distributed power supplies, and a new problem is brought to the operation and management of the traditional power system.
The distributed power supply in the microgrid is an inverter power supply which takes power electronic elements as grid-connected interfaces, and mathematically, the distributed power generation system of the microgrid is a nonlinear system with all parts strongly coupled with each other. In a grid-connected operation mode, the distributed power supply mainly adopts PQ control, and the output power of the distributed power generation system can be ensured to follow a given value to transmit power with a large power grid. The stable operation of the microgrid system determines the stable transmission of power between the microgrid system and a large power grid, and the fault problem in the system can cause the microgrid to be in a destabilization state, so that the construction of a fault-tolerant control strategy is an important component of the design of the distributed power generation system of the microgrid. However, the protection technology is still in the theoretical research stage as the application bottleneck of the micro-grid system. For a typical complex nonlinear system of a microgrid, domestic and foreign scholars apply various fault-tolerant control methods such as fault-tolerant control, adaptive fault-tolerant control, neural network control, sliding-mode fault-tolerant control and the like by adopting an artificial intelligence control technology when researching faults of the microgrid.
A sensor is one of the most important elements in a control system, and a small fault of the sensor may cause misoperation of the control system or false alarm of a fault diagnosis system, resulting in degradation of the performance of the system. Therefore, the sensor fault diagnosis research is very important for improving the performance of the microgrid system. In recent years, observer-based fault reconstruction has attracted more and more attention, and various fault reconstruction observers are widely applied. Such as a sliding mode observer, an adaptive observer, a learning observer, and the like.
Therefore, under the fault state of the micro-grid, a method for realizing real-time monitoring of the fault by the fault-tolerant learning observer and correcting the measurement error of the sensor by using the reconstructed fault signal to form a power stable tracking reference value is researched, and the method has good engineering practical significance.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and aims to ensure the safe and reliable operation of an IIDG (inter-integrated differential) during grid-connected power transmission of a microgrid system and provide a microgrid sensor fault tolerance control method based on a PD (PD type learning observer) which has wide adaptability to various faults of a microgrid sensor.
In order to achieve the purpose, the invention adopts the following technical scheme:
the fault tolerance control method of the micro-grid sensor based on the PD type learning observer comprises the following steps:
step 1, establishing a system closed-loop output feedback controller according to a state space model of a micro-grid inverter type distributed power supply;
step 2, establishing a sensor fault model of the microgrid system, and converting the sensor fault model into an actuator fault model form;
and 3, establishing a sensor fault-tolerant PD type learning observer, solving a reconstructed fault signal, feeding back an output compensated by the reconstructed signal to an output feedback controller, and ensuring the stable tracking of the output power.
As a preferred technical scheme of the invention: the specific steps of the step 1 are as follows:
step 1.1, converting three-phase output into two phases by using a park module according to a three-phase converter structure of the microgrid, and deducing a state space model of an IIDG in the microgrid system under a dq coordinate system;
step 1.2, according to the constructed state space model of the IIDG, a closed-loop output feedback controller is established, and the control law is as follows:
udq=Ky (1)
in the formula (1), y is the system output current and is defined as y ═ iod ioq]TK is a control rate gain matrix;
step 1.3, establishing an augmented micro-grid system model under the control of an output feedback controller, and determining the value of a control law gain matrix K by using a linear matrix inequality method; the inequality is defined as:
Figure BDA0002789399250000021
in the formula (2), χ ═ Aa+BaKCa,AaRelates to the amplification of the inverter output current i in a microgrid systemtd、itqTerminal voltage v of filter capacitorcfd、vcfqAnd bus terminal output current iod、ioqParameter (c) ofaIs a parameter relating to an input variable z, CaIs a unit matrix parameter related to the output current and voltage at the bus terminal, FaIs a parameter related to the system disturbance d, I is the identity matrix.
As a preferred technical scheme of the invention: the specific steps of the step 2 are as follows:
step 2.1, on the basis of the inverter type distributed power supply model, establishing an IIDG sensor fault model as follows:
Figure BDA0002789399250000022
in equation (3), A is the inverter output current i in IIDGtd、itqTerminal voltage v of filter capacitorcfd、vcfqAnd bus terminal output current iod、ioqB is a parameter relating to the input vector z, C is a unit matrix parameter relating to the bus bar terminal output current and voltage, D is a parameter relating to the system disturbance vector w, and the state variable x ═ itd itq iod ioq vcfd vcfq]TZ is the input vector, w is the perturbation vector, Fs=I2As a matrix of error vector coefficients, is a selection of faults, fsRepresents the current measurement error on the dq axis and can be expressed as:
fs=[Δd Δq]T (4)
in the formula (4), ΔdAnd ΔqWhen the sensors are in fault, fault signals of current on a d axis and a q axis are output;
step 2.2, establishing a fault conversion filter, and defining the fault conversion filter as follows:
Figure BDA0002789399250000031
in the formula (5), xsIndicating the state of the filter current of the fault-transfer filter, AsIs a Hurwitz matrix;
step 2.3, integrating the filtered sensor fault model as follows:
Figure BDA0002789399250000032
in the formula (6), the first and second groups,
Figure BDA0002789399250000033
indicating the state of the IIDG inverter output current and the fault transfer filter current,
Figure BDA0002789399250000034
which are its state matrix parameters, m represents the input and disturbance of the system,
Figure BDA0002789399250000035
for its state matrix parameters, fsRepresenting the current measurement error on the dq axis,
Figure BDA0002789399250000036
is its state matrix parameter;
and integrating the filtered sensor fault model to convert the sensor fault model into an actuator fault model form.
As a preferred technical scheme of the invention: the specific steps of the step 3 are as follows:
3.1, establishing a PD type learning observer according to a micro-grid system sensor fault model, and solving PD type learning observer matrixes L and S and a learning time interval tau; define the PD-type learning observer as:
Figure BDA0002789399250000037
in the formula (7), the first and second groups,
Figure BDA0002789399250000038
and
Figure BDA0002789399250000039
respectively estimating the system state, measuring output and estimating and reconstructing a sensor fault signal of the PD type learning observer; l and S are learning observer matrixes, sigma is a constant to be determined, and tau is a learning time interval;
step 3.2, solving a fault reconstruction signal of the PD type learning observer, and defining the state estimation error of the microgrid IIDG system
Figure BDA00027893992500000310
Output estimation error
Figure BDA00027893992500000311
And actuator fault reconstruction error
Figure BDA00027893992500000315
Comprises the following steps:
Figure BDA00027893992500000312
in the formula (8), the first and second groups,
Figure BDA00027893992500000313
and
Figure BDA00027893992500000314
respectively estimating the system state, measuring output and estimating and reconstructing a sensor fault signal of the PD type learning observer;
step 3.3, solving the estimation error kinetic equation of the system as follows:
Figure BDA0002789399250000041
in the formula (9), the reaction mixture,
Figure BDA0002789399250000042
represents the estimation error of the state of the microgrid IIDG system,
Figure BDA0002789399250000043
representing the output estimation error;
step 3.4, calculating the output current compensated by the reconstructed signal, and defining the output current as
Figure BDA0002789399250000044
The current is fed back to the output feedback controller, so that the stable tracking of the output power is ensured.
As a preferred technical scheme of the invention: and the sensor fault model is converted into an actuator fault model form through a fault conversion filter.
As a preferred technical scheme of the invention: the PD type learning observer realizes real-time monitoring of faults and corrects measurement errors of the sensor by using the reconstructed fault signals.
Compared with the prior art, the micro-grid sensor fault tolerance control method based on the PD type learning observer has the following technical effects:
1. the fault-tolerant controller can ensure that the micro-grid system can still keep the global stable output of current when the micro-grid system has a sensor fault, and the output power can accurately track an externally given reference value.
2. The PD type learning observer can autonomously detect the faults of the sensors, and can estimate and reconstruct the fault signals existing in the current system without adding extra sensors.
3. The PD type learning observer introduces a differential term of a measurement output estimation error on the basis of a P type learning observer, and can reconstruct the fault of the micro-grid sensor more quickly and accurately.
4. The fault-tolerant controller consists of a closed-loop output feedback controller, a fault conversion filter and a PD type learning observer, and compared with a single controller, the structure of the fault-tolerant controller has stronger robustness.
Drawings
FIG. 1 is a topological diagram of a main circuit of a three-phase grid-connected converter according to the present invention;
FIG. 2 is a schematic diagram of a microgrid PQ control according to the present invention;
FIG. 3 is a schematic diagram of a microgrid current output feedback control according to the present invention;
fig. 4 is a schematic diagram of fault-tolerant control of a microgrid system according to the present invention.
Detailed Description
The present invention will be further explained with reference to the drawings so that those skilled in the art can more deeply understand the present invention and can carry out the present invention, but the present invention will be explained below by referring to examples, which are not intended to limit the present invention.
In FIG. 1, vdThe direct current side voltage after the micro power supply is simplified can be supplied by wind driven generators, solar photovoltaic panels, fuel cells and other energy sources. CdIs a DC side filter capacitor, T1~T6Is an IGBT power device, and the output voltage of the inverter is va,vb,vcThe output current of the inverter is ia,ib,ic,Ra=Rb=RcR is the total converter and filter losses. L is1a=L1b=L1c=L1Is an inverter side inductor, L2a=L2b=L2c=L2Is a network side inductor, CfIs a filter capacitor, vcfa,vcfb,vcfcRespectively, the filter capacitor terminal voltages. The output current of the inverter passes through the LCL filter to obtain a network inlet current ioa,iob,ioc,vsa,vsb,vscIs the three-phase grid voltage with the midpoint O.
In fig. 2, an active reference value P is setrefAnd a reactive reference value QrefObtaining a d-axis current reference value i through calculationdrefAnd q-axis current reference value iqref。vtabcAnd itabcRespectively the output voltage and current of the converter. The output power of the converter is supplied to the grid through the LCL filter. Wherein R isnFor total losses of converters and filters, L1nAnd L2nIs the total inductance of the filter, CnIs a filter capacitor, VcfIs the capacitor voltage. Voltage and current at output terminal are respectively vsAnd io
Referring to fig. 1 and 2, during grid-connected operation of the microgrid, an inverter of the microgrid is controlledThe manufacturing method mainly adopts a PQ control method. In the operation mode, the public power grid supports the frequency and the voltage inside the microgrid, and the inverters of the distributed micro power supplies use the frequency and the voltage of the public power grid as reference values, use the reference values as users to transmit active power and reactive power, and transmit redundant electric energy to the public power grid. The micro-grid PQ control is established based on a double-loop control mode under a dq coordinate system, and essentially detects the output voltage of an inverter, carries out dq conversion, and sets an active reference value PrefAnd a reactive reference value QrefObtaining a d-axis current reference value i through calculationdrefAnd q-axis current reference value iqref. The inverter used in the figure is a six-pulse bridge based on IGBTs, constituting a three-phase voltage source converter. v. oftabcAnd itabcRespectively the output voltage and current of the converter. The output power of the converter is supplied to the grid through the LCL filter. Wherein R isnFor total losses of converters and filters, L1nAnd L2nIs the total inductance of the filter, CnIs a filter capacitor, VcfIs the capacitor voltage. Voltage and current at output terminal are respectively vsAnd io. Three-phase alternating current obtains the phase theta of voltage and current through a phase-locked loop SPLL, and the phase theta is used for real-time tracking of reference current i by an inner loop controlled by a double loop in Park conversiondrefAnd iqref. Converting into three phases by coordinate transformation, and outputting SPWM reference voltage uabc. The phase locked loop SPLL performs tracking control of the current and provides a frequency reference for coordinate transformation.
The microgrid system comprises a distributed power supply, a sensor, a direct current side filter capacitor, a three-phase inverter, an LCL filter, a fault-tolerant controller and the like; the fault-tolerant controller consists of an output feedback controller, a fault conversion filter, a PD type learning observer and the like, can reconstruct a fault signal of output current when a micro-grid sensor fails, and inputs the corrected feedback signal into the closed-loop output feedback controller so as to ensure the stability of the output power of the micro-grid; the fault-tolerant controller is regulated by an output feedback controller and a signal regulator (comprising an inverse park converter and an SPWM modulator) through an externally given current input reference value rThe method comprises the steps of preparing a signal u, providing an SPWM pulse signal for an inverter of an inverter type distributed power supply, enabling a system output y to pass through an output filter in the state that a sensor fails, converting a sensor failure model into an actuator failure model, inputting the output into a PD type learning observer, and enabling the designed PD type learning observer to rapidly output current after filtering
Figure BDA0002789399250000051
Reconstructing the fault signal, and reconstructing the reconstructed fault signal
Figure BDA0002789399250000052
And output current
Figure BDA0002789399250000053
The difference value is used as a correction feedback signal and input into an output feedback controller, and then the running state of the system is regulated.
In a micro-grid system, a distributed power supply is mostly supplied by wind driven generators, solar photovoltaic panels, fuel cells and other energy sources, and is simplified into direct-current voltage serving as a direct-current source of the system, and is connected with a filter capacitor in parallel to play a role in filtering the direct-current source. The connected three-phase inverter takes IGBT as a power device, converts direct current into three-phase alternating current, and the inverter outputs current and voltage which pass through the LCL filter to obtain network access current and voltage respectively. The three-phase alternating current obtains the phase theta of voltage and current through the phase-locked loop, and the phase-locked loop is used for coordinate transformation, meanwhile, the phase-locked loop realizes tracking control of the current and provides frequency reference for coordinate transformation.
The fault tolerance control method of the micro-grid sensor based on the PD type learning observer comprises the following steps: step 1, establishing a system closed-loop output feedback controller according to a state space model of a micro-grid inverter type distributed power supply; step 2, establishing a sensor fault model of the microgrid system, and converting the sensor fault model into an actuator fault model form; and 3, establishing a sensor fault-tolerant PD type learning observer, solving a reconstructed fault signal, feeding back an output compensated by the reconstructed signal to an output feedback controller, and ensuring the stable tracking of the output power.
In the attached figure 3, a dq coordinate system model under the control of the micro-grid system PQ is established, an output feedback controller is designed, and a reference current i calculated through reference power is inputdrAnd iqrThe SPWM modulation signal u is output through the output feedback controller and coordinate transformation, the output current of the system is controlled, the stable tracking reference value of the output power is ensured, and the method comprises the following steps:
step 1.1, converting three-phase output into two phases by using a park module according to a three-phase converter structure of the microgrid, and deducing a state space model of an IIDG in the microgrid system under a dq coordinate system;
step 1.2, according to the constructed state space model of the IIDG, a closed-loop output feedback controller is established, and the control law is as follows:
udq=Ky (1)
in the formula (1), y is the system output current and is defined as y ═ iod ioq]TK is a control rate gain matrix;
step 1.3, establishing an augmented micro-grid system model under the control of an output feedback controller, and determining the value of a control law gain matrix K by using a linear matrix inequality method; the inequality is defined as:
Figure BDA0002789399250000061
in the formula (2), χ ═ Aa+BaKCa,AaRelates to the amplification of the inverter output current i in a microgrid systemtd、itqTerminal voltage v of filter capacitorcfd、vcfqAnd bus terminal output current iod、ioqParameter (c) ofaIs a parameter relating to an input variable z, CaIs a unit matrix parameter related to the output current and voltage at the bus terminal, FaIs about a systemThe parameter of the disturbance d, I, is the identity matrix. Solving variable gamma in linear matrix inequality by using LMI (least mean squares) minimization method1And v and K corresponding to the minimum value. The controller designed in the steps reduces the influence of the interference on the output to the minimum through a minimization method, thereby achieving the purpose that the controller has robustness on the interference and ensuring the realization of a control target.
In the attached figure 4, a reference value r is input by a given current, a modulation signal u is obtained after the modulation by an output feedback controller and a signal regulator (including an inverse park converter and an SPWM modulator), a PWM pulse signal is provided for an inverter of an inverter type distributed power supply, when a sensor fails, a system output y firstly passes through a fault conversion filter, a sensor fault model is converted into an actuator fault model, then an output current is input into a PD type learning observer, the designed learning observer can rapidly reconstruct a fault signal in the filtered output current, a difference value between the reconstructed fault signal and an actual output current is input into a controller as a correction feedback signal, and then the operation state of the system is adjusted, and the steps are as follows:
step 2.1, on the basis of the inverter type distributed power supply model, establishing an IIDG sensor fault model as follows:
Figure BDA0002789399250000071
in equation (3), A is the inverter output current i in IIDGtd、itqTerminal voltage v of filter capacitorcfd、vcfqAnd bus terminal output current iod、ioqB is a parameter relating to the input vector z, C is a unit matrix parameter relating to the bus bar terminal output current and voltage, D is a parameter relating to the system disturbance vector w, and the state variable x ═ itd itq iod ioq vcfd vcfq]TZ is the input vector, w is the perturbation vector, Fs=I2The error vector coefficient matrix is selected for faults;
in the formula (3), the first and second groups,
Figure BDA0002789399250000072
fsrepresents the current measurement error on the dq axis and can be expressed as:
Figure BDA0002789399250000073
in the formula (4), ΔdAnd ΔqWhen the sensors are in fault, fault signals of current on a d axis and a q axis are output;
step 2.2, establishing a fault conversion filter, and defining the fault conversion filter as follows:
Figure BDA0002789399250000074
in the formula (5), xsIndicating the state of the filter current of the fault-transfer filter, AsIs a Hurwitz matrix;
step 2.3, integrating the filtered sensor fault model as follows:
Figure BDA0002789399250000081
in the formula (6), the first and second groups,
Figure BDA0002789399250000082
indicating the state of the IIDG inverter output current and the fault transfer filter current,
Figure BDA0002789399250000083
which are its state matrix parameters, m represents the input and disturbance of the system,
Figure BDA0002789399250000084
for its state matrix parameters, fsRepresenting the current measurement error on the dq axis,
Figure BDA0002789399250000085
is its state matrix parameter;
in the formula (6), the first and second groups,
Figure BDA0002789399250000086
Figure BDA0002789399250000087
and integrating the filtered sensor fault model to convert the sensor fault model into an actuator fault model form. 3.1, establishing a PD type learning observer according to a micro-grid system sensor fault model, and solving PD type learning observer matrixes L and S and a learning time interval tau; define the PD-type learning observer as:
Figure BDA0002789399250000088
in the formula (7), the first and second groups,
Figure BDA0002789399250000089
and
Figure BDA00027893992500000810
respectively estimating the system state, measuring output and estimating and reconstructing a sensor fault signal of the PD type learning observer; l and S are learning observer matrixes, sigma is a constant to be determined, and tau is a learning time interval;
step 3.2, solving a fault reconstruction signal of the PD type learning observer, and defining the state estimation error of the microgrid IIDG system
Figure BDA00027893992500000811
Output estimation error
Figure BDA00027893992500000812
And actuator fault reconstruction error
Figure BDA00027893992500000817
Comprises the following steps:
Figure BDA00027893992500000813
in the formula (8), the first and second groups,
Figure BDA00027893992500000814
and
Figure BDA00027893992500000815
respectively estimating the system state, measuring output and estimating and reconstructing a sensor fault signal of the PD type learning observer;
step 3.3, solving the estimation error kinetic equation of the system as follows:
Figure BDA00027893992500000816
in the formula (9), the reaction mixture,
Figure BDA0002789399250000091
represents the estimation error of the state of the microgrid IIDG system,
Figure BDA0002789399250000092
representing the output estimation error;
step 3.4, calculating the output current compensated by the reconstructed signal, and defining the output current as
Figure BDA0002789399250000093
The current is fed back to the output feedback controller, so that the stable tracking of the output power is ensured.
In specific implementation, referring to fig. 1 and fig. 2, relevant parameter settings are shown in table 1
Figure BDA0002789399250000094
TABLE 1 microgrid system circuit
Referring to fig. 3 and 4, the relevant parameter settings are as follows:
by constructing an augmentation system model and solving the controller control rate by using an LMI minimization method, the control law of the output feedback controller, namely control gain parameters, is obtained as follows:
Figure BDA0002789399250000095
and optimizing each matrix parameter by using an LMI (local mean minimization) method to solve the minimum value of the inequality, wherein the solved matrixes S and L are as follows:
Figure BDA0002789399250000096
Figure BDA0002789399250000097
the invention utilizes the improved PD type learning observer to detect and reconstruct the fault in the output measurement of the micro-grid system, and feeds back the reconstructed fault signal to the controller, thereby finally stably controlling the accurate power transmission between the micro-grid and the large grid when the micro-grid is connected.
On the basis of analyzing a grid-connected structure of a micro-grid system and an operation control method thereof, aiming at the problem of sensor faults of an inverter distributed generator (IIDG) in the micro-grid system, an IIDG sensor fault model under a dq coordinate system is established to describe the influence of the IIDG sensor fault model on the system performance; the IIDG sensor fault tolerance control method based on the learning observer is provided; designing a learning observer by using the established fault model, realizing real-time monitoring of the fault, accurately reconstructing the fault of the sensor, and correcting the measurement error of the sensor by using the reconstructed fault signal; the fault-tolerant control scheme provided ensures safe and reliable operation of the IIDG when grid-connected power of the micro-grid system is transmitted, and has wide adaptability to various faults of the micro-grid sensor.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention, and are not intended to limit the scope of the present invention, and any person skilled in the art should understand that equivalent changes and modifications made without departing from the concept and principle of the present invention should fall within the protection scope of the present invention.

Claims (5)

1. The fault tolerance control method of the micro-grid sensor based on the PD type learning observer is characterized by comprising the following steps of:
step 1, establishing a system closed-loop output feedback controller according to a state space model of a micro-grid inverter type distributed power supply;
step 2, establishing a sensor fault model of the microgrid system, and converting the sensor fault model into an actuator fault model form;
step 3, establishing a sensor fault-tolerant PD type learning observer, solving a reconstructed fault signal, feeding back an output compensated by the reconstructed signal to an output feedback controller, and ensuring stable tracking of output power;
the specific steps of the step 1 are as follows:
step 1.1, converting three-phase output into two phases by using a park module according to a three-phase converter structure of the microgrid, and deducing a state space model of an IIDG in the microgrid system under a dq coordinate system;
step 1.2, according to the constructed state space model of the IIDG, a closed-loop output feedback controller is established, and the control law is as follows:
udq=Ky (1)
in the formula (1), y is the system output current and is defined as y ═ iod ioq]TK is a control rate gain matrix;
step 1.3, establishing an augmented micro-grid system model under the control of an output feedback controller, and determining the value of a control law gain matrix K by using a linear matrix inequality method; the inequality is defined as:
Figure FDA0003286755390000011
in the formula (2), χ ═ Aa+BaKCa,AaRelates to the amplification of the inverter output current i in a microgrid systemtd、itqTerminal voltage v of filter capacitorcfd、vcfqAnd bus terminal output current iod、ioqParameter (c) ofaIs a parameter relating to an input variable z, CaIs a unit matrix parameter related to the output current and voltage at the bus terminal, FaIs a parameter related to the system disturbance d, I is the identity matrix.
2. The microgrid sensor fault tolerance control method based on a PD-type learning observer is characterized in that the specific steps of the step 2 are as follows:
step 2.1, on the basis of the inverter type distributed power supply model, establishing an IIDG sensor fault model as follows:
Figure FDA0003286755390000012
in equation (3), A is the inverter output current i in IIDGtd、itqTerminal voltage v of filter capacitorcfd、vcfqAnd bus terminal output current iod、ioqB is a parameter relating to the input vector z, C is a unit matrix parameter relating to the bus bar terminal output current and voltage, D is a parameter relating to the system disturbance vector w, and the state variable x ═ itd itq iod ioq vcfd vcfq]TZ is the input vector, w is the perturbation vector, Fs=I2As a matrix of error vector coefficients, is a selection of faults, fsRepresents the current measurement error on the dq axis and can be expressed as:
fs=[Δd Δq]T (4)
in the formula (4), ΔdAnd ΔqWhen the sensors are in fault, fault signals of current on a d axis and a q axis are output;
step 2.2, establishing a fault conversion filter, and defining the fault conversion filter as follows:
Figure FDA0003286755390000021
in the formula (5), xsIndicating the state of the filter current of the fault-transfer filter, AsIs a Hurwitz matrix;
step 2.3, integrating the filtered sensor fault model as follows:
Figure FDA0003286755390000022
in the formula (6), the first and second groups,
Figure FDA0003286755390000023
indicating the state of the IIDG inverter output current and the fault transfer filter current,
Figure FDA0003286755390000024
which are its state matrix parameters, m represents the input and disturbance of the system,
Figure FDA0003286755390000025
for its state matrix parameters, fsRepresenting the current measurement error on the dq axis,
Figure FDA0003286755390000026
is its state matrix parameter;
and integrating the filtered sensor fault model to convert the sensor fault model into an actuator fault model form.
3. The microgrid sensor fault tolerance control method based on a PD-type learning observer is characterized in that the specific steps of the step 3 are as follows:
3.1, establishing a PD type learning observer according to a micro-grid system sensor fault model, and solving PD type learning observer matrixes L and S and a learning time interval tau; define the PD-type learning observer as:
Figure FDA0003286755390000027
in the formula (7), the first and second groups,
Figure FDA0003286755390000028
and
Figure FDA0003286755390000029
respectively estimating the system state, measuring output and estimating and reconstructing a sensor fault signal of the PD type learning observer; l and S are learning observer matrixes, sigma is a constant to be determined, and tau is a learning time interval;
step 3.2, solving a fault reconstruction signal of the PD type learning observer, and defining the state estimation error of the microgrid IIDG system
Figure FDA00032867553900000210
Output estimation error
Figure FDA00032867553900000211
And actuator fault reconstruction error
Figure FDA00032867553900000212
Comprises the following steps:
Figure FDA00032867553900000213
in the formula (8), the first and second groups,
Figure FDA0003286755390000031
and
Figure FDA0003286755390000032
respectively estimating the system state, measuring output and estimating and reconstructing a sensor fault signal of the PD type learning observer;
step 3.3, solving the estimation error kinetic equation of the system as follows:
Figure FDA0003286755390000033
in the formula (9), the reaction mixture,
Figure FDA0003286755390000034
represents the estimation error of the state of the microgrid IIDG system,
Figure FDA0003286755390000035
representing the output estimation error;
step 3.4, calculating the output current compensated by the reconstructed signal, and defining the output current as
Figure FDA0003286755390000036
The current is fed back to the output feedback controller, so that the stable tracking of the output power is ensured.
4. The microgrid sensor fault tolerance control method based on a PD-type learning observer is characterized in that a sensor fault model is converted into an actuator fault model form through a fault conversion filter.
5. The microgrid sensor fault tolerance control method based on a PD-type learning observer is characterized in that the PD-type learning observer realizes real-time monitoring of faults and corrects measurement errors of a sensor by using a reconstructed fault signal.
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