CN110729760B - Wind-solar hybrid power generation system - Google Patents
Wind-solar hybrid power generation system Download PDFInfo
- Publication number
- CN110729760B CN110729760B CN201911052677.9A CN201911052677A CN110729760B CN 110729760 B CN110729760 B CN 110729760B CN 201911052677 A CN201911052677 A CN 201911052677A CN 110729760 B CN110729760 B CN 110729760B
- Authority
- CN
- China
- Prior art keywords
- grid
- converter
- side converter
- fed
- conversion circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
Landscapes
- Control Of Eletrric Generators (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention provides a wind-solar hybrid power generation system, which comprises: the double-fed generator comprises a double-fed generator, a photovoltaic array and a double-fed converter; the double-fed generator is connected with a power grid through a double-fed converter; the double-fed converter is internally provided with a DC/DC conversion circuit of which the output side is connected with a direct current bus, and the input side of the DC/DC conversion circuit is used for connecting a photovoltaic array; the controller in the double-fed converter is used for controlling the DC/DC conversion circuit to output electric energy to the direct current bus, and then in the actual operation process of the double-fed generator, the power allowance of the grid-side converter in the double-fed converter is fully utilized, the energy output by the photovoltaic array is connected into the grid-side converter, wind power generation and photovoltaic power generation are transmitted simultaneously, and the utilization rate of the power capacity of the grid-side converter is improved.
Description
Technical Field
The invention relates to the technical field of automatic control, in particular to a wind and light hybrid power generation system.
Background
For the double-fed wind generating set, a grid-side converter of a double-fed converter of the double-fed wind generating set is only responsible for transmitting slip power of the double-fed generator; in addition, when the power capacity of the grid-side converter of the doubly-fed converter is designed, the prior art is designed according to the limit slip power.
However, during the actual operation of the doubly-fed generator, the power capacity utilization of the grid-side converter is very limited, and the smaller the slip is, the smaller the power that the grid-side converter of the doubly-fed converter is responsible for transmitting is. If the doubly-fed generator is in a synchronous rotating speed state, the grid-side converter is in a standby state, the utilization rate of the power capacity of the grid-side converter is zero at the moment, and the power capacity of the grid-side converter is idle.
Disclosure of Invention
In view of this, the embodiment of the invention provides a wind and photovoltaic hybrid power generation system to improve the utilization rate of the grid-side converter power capacity of a doubly-fed converter in the wind and photovoltaic hybrid power generation system.
In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:
the invention discloses a wind-solar hybrid power generation system, which comprises: the double-fed generator comprises a double-fed generator, a photovoltaic array and a double-fed converter;
the double-fed generator is connected with a power grid through the double-fed converter;
the double-fed converter is internally provided with a DC/DC conversion circuit of which the output side is connected with a direct current bus, and the input side of the DC/DC conversion circuit is used for connecting the photovoltaic array;
and the controller in the double-fed converter is used for controlling the DC/DC conversion circuit to output electric energy to the direct current bus.
Optionally, in the wind-solar hybrid power generation system, when the controller is configured to control the DC/DC conversion circuit to output the electric energy to the DC bus, the controller is specifically configured to:
determining an output power instruction value of a DC/DC conversion circuit in the doubly-fed converter according to an active current given value of a grid-side converter in the doubly-fed converter;
and generating a corresponding PWM signal according to the output power instruction value of the DC/DC conversion circuit, and outputting the PWM signal to the control end of the DC/DC conversion circuit.
Optionally, in the wind-solar hybrid power generation system, when the controller is configured to determine an output power command value of a DC/DC conversion circuit in the doubly-fed converter according to an active current given value of a grid-side converter in the doubly-fed converter, the controller is specifically configured to:
if the active current given value of the grid-side converter is smaller than or equal to a first preset value, determining that the output power instruction value of the DC/DC conversion circuit is the power value of the maximum power point;
if the given value of the active current of the grid-side converter is larger than or equal to a second preset value, judging that the DC/DC conversion circuit enters a limiting MPPT state, and determining that the output power instruction value of the DC/DC conversion circuit is the power value before the DC/DC conversion circuit enters the limiting MPPT state;
and if the given value of the active current of the grid-side converter is greater than or equal to a third preset value, determining that the output power instruction value of the DC/DC conversion circuit is a power value which is gradually reduced according to a preset step length.
Optionally, in the wind-solar hybrid power generation system, the first preset value is
The second preset value is
The third preset value is
Wherein, K1A first hysteresis value, K, of a rated current utilization factor of the grid-side converter2A second hysteresis value, K, of the rated current utilization factor of the grid-side converter3A third hysteresis value, I, of the rated current utilization factor of the grid-side converterrateRepresents the maximum current, I, of the grid-side converter in steady-state operationq_refRepresenting a reactive current setpoint of the grid-side converter.
Optionally, in the above-mentioned wind and photovoltaic hybrid power generation system, when the corresponding PWM signal is generated according to the output power command value of the DC/DC conversion circuit and output to the control terminal of the DC/DC conversion circuit, the PWM signal is specifically configured to:
determining a working current instruction value of the DC/DC conversion circuit according to the output power instruction value of the DC/DC conversion circuit;
calculating to obtain a difference value of subtracting a working current feedback value from a working current instruction value of the DC/DC conversion circuit;
and performing PI regulation on the difference value to generate the PWM signal.
Optionally, in the wind-solar hybrid power generation system, the capacity of the photovoltaic array is the rated slip power of the doubly-fed generator.
Optionally, in the wind-solar hybrid power generation system, the doubly-fed converter includes: the controller comprises a machine side converter, a grid side converter, a direct current bus unit, a first switch unit, a second switch unit, a controller and a DC/DC conversion circuit; wherein the content of the first and second substances,
the first switch unit is connected between the stator of the doubly-fed generator and a power grid;
the alternating current side of the machine side converter is connected with the rotor of the doubly-fed generator;
the direct current side of the machine side converter, the direct current side of the grid side converter, the output side of the DC/DC conversion circuit and two ends of the direct current bus unit are connected with a direct current bus;
the alternating current side of the grid-side converter is connected with a power grid through the second switch unit;
the controller is respectively connected with the machine side converter, the grid side converter, the direct current bus unit, the first switch unit, the second switch unit and the control end of the DC/DC conversion circuit, and is further used for controlling the machine side converter and the grid side converter to work in corresponding states.
Optionally, in the wind-solar hybrid power generation system, when the controller is configured to control the machine-side converter and the grid-side converter to operate in corresponding states, the controller is specifically configured to:
when the doubly-fed generator works in a sub-synchronous running state, the machine side converter is controlled to receive part of electric energy on the direct-current bus, convert the electric energy and output the converted electric energy to a rotor of the doubly-fed generator, and meanwhile, the grid side converter is controlled to receive the other part of electric energy on the direct-current bus, convert and grid-connect;
when the doubly-fed generator works in a synchronous running state, controlling the grid-side converter to receive all electric energy on the direct-current bus to carry out conversion grid connection;
when the doubly-fed generator works in a super-synchronous running state, the machine side converter is controlled to receive rotor electric energy of the doubly-fed generator, convert the rotor electric energy and output the converted rotor electric energy to the direct-current bus, and meanwhile, the grid side converter is controlled to receive all electric energy on the direct-current bus to convert and grid the direct-current bus.
Optionally, in the wind-solar hybrid power generation system, the doubly-fed converter further includes: the third switching unit is arranged on the electric energy output loop of the photovoltaic array; and the control end of the third switching unit is connected with the controller.
Optionally, in the wind-solar hybrid power generation system, the DC/DC conversion circuit is: a DC/DC boost circuit, or a DC/DC buck-boost circuit.
Optionally, in the wind-solar hybrid power generation system, the dc bus unit includes: a DC bus capacitor and a crowbar circuit;
and the direct current bus capacitor is connected with the crowbar circuit in parallel.
Optionally, in the wind-solar hybrid power generation system, the crowbar circuit includes: a resistor and a switching tube;
one end of the resistor is connected with the anode of the direct current bus, the other end of the resistor is connected with the drain electrode of the switch tube, and the source electrode of the switch tube is connected with the cathode of the direct current bus.
The wind and light hybrid power generation system provided based on the embodiment of the invention comprises: the double-fed generator comprises a double-fed generator, a photovoltaic array and a double-fed converter; the double-fed generator is connected with a power grid through a double-fed converter; the double-fed converter is internally provided with a DC/DC conversion circuit of which the output side is connected with a direct current bus, and the input side of the DC/DC conversion circuit is used for connecting a photovoltaic array; the controller in the double-fed converter is used for controlling the DC/DC conversion circuit to output electric energy to the direct current bus, the power allowance of the grid-side converter in the double-fed converter can be fully utilized in the actual operation process of the double-fed generator, the energy output by the photovoltaic array is connected into the grid-side converter, the utilization rate of the power capacity of the grid-side converter is improved, wind power generation and photovoltaic power generation are transmitted simultaneously, and the hardware cost of the wind-solar hybrid power generation system is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic structural diagram of a wind-solar hybrid power generation system according to an embodiment of the present invention;
FIG. 2 is a control schematic block diagram of a doubly-fed converter in a wind-solar hybrid power generation system according to an embodiment of the present invention;
FIG. 3 is a flowchart of a control scheme of a doubly-fed converter in a wind-solar hybrid power generation system according to an embodiment of the present invention;
FIG. 4 is a flow chart of a control scheme of a doubly-fed converter in another wind-solar hybrid power generation system disclosed by the embodiment of the invention;
fig. 5 is a schematic structural diagram of a doubly-fed converter disclosed in the embodiment of the present invention;
fig. 6 is a schematic circuit structure diagram of a doubly-fed converter disclosed in the embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the application provides a wind and light hybrid power generation system, which aims to improve the utilization rate of the power capacity of a grid-side converter of a double-fed converter in the wind and light hybrid power generation system.
Referring to fig. 1, the wind-solar hybrid power generation system includes: doubly-fed generator 601, photovoltaic array 602, and doubly-fed converter 603.
The doubly-fed generator 601 and the photovoltaic array 602 are respectively connected with the grid through a doubly-fed converter 603.
The doubly-fed converter 603 is provided with a DC/DC converter circuit 107 having an output side connected to the DC bus, and an input side of the DC/DC converter circuit 107 is connected to the photovoltaic array 602.
The controller 106 in the doubly-fed converter 603 is used for controlling the DC/DC conversion circuit 107 to output electric energy to the DC bus.
Specifically, the capacity of the photovoltaic array 602 in the wind-solar hybrid power generation system is the rated slip power of the doubly-fed generator 601.
In the control process of the doubly-fed converter, the controller 106 controls the grid-side converter in the same way as the prior art, and refer to the upper half shown in fig. 2: by setting the voltage on the DC bus to a given value Udc_refMinus the voltage feedback value Udc_fedPerforming PI regulation on the difference value to obtain an active current given value I of the grid-side converterd_ref(ii) a Using the active current to set the value Id_refSubtracting the active current feedback value Id_fedPerforming PI regulation on the difference value to obtain active regulation quantity; then uses the voltage active component UdAnd the difference value of the active regulating quantity is subtracted and input into one input end of the SVPWM module. And, the given value of reactive current I of the grid-side converterq_refSubtracting the reactive current feedback value Iq_fedPerforming PI regulation on the difference value to obtain a reactive regulation quantity; then with the voltage reactive component UqAnd the difference value of the reactive power regulating quantity is subtracted and input into the other input end of the SVPWM module. When the doubly-fed generator is in a normal operation state, the given reactive current value I of the grid-side converterq_refTypically 0.
On the basis of the above control scheme, the controller in this embodiment adds a PWM output control signal to control the DC/DC conversion circuit of the doubly-fed converter, that is, the controller 106 is further configured to control the DC/DC conversion circuit to output electric energy to the DC bus, and a specific process of this part may refer to fig. 3, and mainly includes the following steps:
s101, determining an output power instruction value of a DC/DC conversion circuit in the doubly-fed converter according to an active current given value of a grid-side converter in the doubly-fed converter.
Wherein, the given value of the active current of the grid-side converter is Id_ref(ii) a The output power command value of the DC/DC conversion circuit is: the output side of the DC/DC conversion circuit outputs power to the DC bus.
Specifically, the specific execution process of step S101 includes:
(1) if the active current given value I of the grid-side converterd_refLess than or equal to a first preset value
The output power command value of the DC/DC conversion circuit is determined as the power value of the maximum power point.
Wherein, K1For rated current utilization factor of grid-side converterFirst hysteresis value, IrateRepresents the maximum current, I, of the grid-side converter in steady-state operationq_refRepresenting the reactive current setpoint of the grid-side converter.
In practical application, K1The value of (b) can be determined according to the specific application environment and system capacity, and only the controller needs to have enough regulation time. First preset value
The size of (A) is taken to be K1The values are positive and negative.
If the active current given value I of the grid-side converterd_refIf the value is negative, the doubly-fed generator is in a sub-synchronous running state, and at the moment, after the controller carries out MPPT (Maximum power point Tracking) operation on the electric energy output by the photovoltaic array, the controller controls the DC/DC conversion circuit to directly use the electric energy of the photovoltaic array as the Maximum power PmpptAnd outputting the data.
If the active current given value I of the grid-side converterd_refIf the value is 0, the doubly-fed generator is in a synchronous operation state, and if the capacity of the photovoltaic array in the wind-solar hybrid power generation system is designed to be less than or equal to the rated slip power of the doubly-fed generator, the photovoltaic array can also directly use the maximum power PmpptAnd outputting the data.
If the active current given value I of the grid-side converterd_refIf the value is positive, the doubly-fed generator is in a super-synchronous running state, at the moment, a machine side converter in the doubly-fed converter can transmit active power to a power grid, and if the capacity of a photovoltaic array in the system is designed to be smaller than the slip power of the doubly-fed generator, the photovoltaic array can also directly use the maximum power PmpptAnd outputting the data.
(2) If the active current given value I of the grid-side converterd refGreater than or equal to a second preset value
It is determined that the DC/DC converter circuit enters the MPPT limiting state and an output power command value of the DC/DC converter circuit is determinedThe power value before the DC/DC conversion circuit enters the limiting MPPT state is obtained.
Wherein, K2A second hysteresis value, I, of the rated current utilization factor of the grid-side converterrateRepresents the maximum current, I, of the grid-side converter in steady-state operationq_refRepresenting the reactive current setpoint of the grid-side converter. In practical application, K2The value of (b) can be determined according to the specific application environment and system capacity, and only the controller needs to have enough regulation time.
It should be noted that when the active current of the grid-side converter is given by a given value Id refGreater than or equal to a second preset value
During the operation, the doubly-fed generator is in a super-synchronous operation state, at the moment, the power output by the machine side converter is large, and the power output by the photovoltaic array needs to be limited. Therefore, the sum of the power output by the machine side converter and the power output by the photovoltaic array is ensured not to exceed the rated capacity of the grid side converter.
(3) If the given value of the active current of the grid-side converter is greater than or equal to a third preset value
The output power command value of the DC/DC conversion circuit is determined to be a power value that is successively decreased by a preset step.
Wherein, K3A third hysteresis value, I, of the rated current utilization factor of the grid-side converterrateRepresents the maximum current, I, of the grid-side converter in steady-state operationq_refRepresenting the reactive current setpoint of the grid-side converter. In practical application, K3The value of (b) can be determined according to the specific application environment and system capacity, and only the controller needs to have enough regulation time.
It should be noted that, when the given value of the active current of the grid-side converter is greater than or equal to the third preset value
When the temperature of the water is higher than the set temperature,the doubly-fed generator is in a super-synchronous running state, at the moment, the output power of the machine side converter is very high, the output power of the photovoltaic array needs to be further reduced, namely the output power of the photovoltaic array is gradually reduced according to a preset step length, namely the output power of the photovoltaic array is judged every time to be obtained
And then, reducing the output power of the primary photovoltaic array to ensure that the sum of the output power of the machine side converter and the output power of the photovoltaic array is not more than the rated capacity of the grid side converter.
Also, it should be noted that K1、K2、K3The value relationship of each value is K1<K2<K3As long as sufficient adjustment time is ensured, each value can be optimally designed according to the system capacity, and is not specifically limited herein.
According to the above, the output power instruction value of the DC/DC conversion circuit is obtained according to the maximum power P of the photovoltaic arraympptTo proceed to receive Id_refThe limited MPPT is obtained and then step S102 is performed.
And S102, generating a corresponding PWM signal according to the output power instruction value of the DC/DC conversion circuit, and outputting the PWM signal to the control end of the DC/DC conversion circuit.
After the DC/DC conversion circuit receives the corresponding PWM signal, the corresponding device in the DC/DC conversion circuit is controlled to work according to the signal, so that the power output by the photovoltaic array is connected to the grid-side converter by fully utilizing the power margin of the grid-side converter in the double-fed converter in the actual operation process of the double-fed generator, the utilization rate of the power capacity of the grid-side converter is improved, the purposes of simultaneously transmitting wind power generation and photovoltaic power generation and reducing the hardware cost of the wind-solar hybrid power generation system are achieved.
In the wind-solar hybrid power generation system provided by this embodiment, the control scheme is applied to the controller of the doubly-fed converter, and on the basis of the control scheme in the prior art, one path of PWM output control signal is added to control the DC/DC conversion circuit to output electric energy to the DC bus, so as to achieve the purpose of outputting electric energy to the DC busTo the purpose of controlling the output power of the photovoltaic array; because the double-fed converter is a converter containing a DC/DC conversion circuit, the wind and light hybrid power generation system can make full use of the power margin of the grid-side converter in the double-fed converter in the actual operation process of the double-fed generator, and the energy output by the photovoltaic array is connected into the grid-side converter, so that the utilization rate of the power capacity of the grid-side converter is improved, the simultaneous transmission of wind power generation and photovoltaic power generation is realized, and the hardware cost of the wind and light hybrid power generation system is reduced. The control scheme in the wind-solar hybrid power generation system controls the output power of the photovoltaic array to be controlled by the power Idc_fedAnd the limited MPPT can ensure the stable operation of the wind-solar hybrid power generation system. Finally, the capacity of the photovoltaic array in the wind-solar hybrid power generation system is set as the slip power of the doubly-fed generator, so that the economic benefit ratio of the system can be increased.
Optionally, referring to fig. 4, a specific implementation procedure of step S102 includes the following steps:
s201, determining an operating current instruction value of the DC/DC conversion circuit according to the output power instruction value of the DC/DC conversion circuit.
Wherein the DC/DC conversion circuit has an operating current command value of I in FIG. 2dc_pv. See the lower half of fig. 2, according to the maximum power P of the photovoltaic arraympptTo proceed to receive Id_refAfter the limited MPPT obtains the output power command value of the DC/DC converter circuit, the operating current command value I of the DC/DC converter circuit may be calculated according to the corresponding voltage requirementdc_pv。
S202, calculating to obtain a difference value of subtracting the working current feedback value from the working current instruction value of the DC/DC conversion circuit.
The operating current command value I of the DC/DC converter circuit is setdc_pvAnd the working current feedback value Idc_fedIntroducing a comparison node, and calculating to obtain I through the comparison nodedc_pv-Id_refA difference of (d); then step S203 is performed.
And S203, performing PI regulation on the difference value to generate a PWM signal.
As shown in the bottom row of fig. 2, the difference I is divideddc_pv-Id_refAnd after PI regulation, generating a PWM output control signal through a PWM generation module. And outputting the PWM output control signal to a control end of the DC/DC conversion circuit, and controlling the DC/DC conversion circuit to output electric energy to a direct current bus.
Optionally, referring to fig. 5, the doubly-fed converter in the wind and photovoltaic hybrid power generation system specifically includes: a machine-side converter 101, a grid-side converter 102, a direct-current bus unit 103, a first switching unit 104, a second switching unit 105, a controller 106, and a DC/DC conversion circuit 107; wherein the content of the first and second substances,
the first switching unit 104 is connected between the stator of the doubly fed generator and the grid.
Specifically, the first switching unit 104 is used for controlling the on/off of a loop between the stator of the doubly-fed generator and the grid.
The ac side of the machine side converter 101 is connected to the rotor of the doubly fed generator.
Specifically, the ac side of the machine-side converter 101 may be connected to the rotor of the doubly-fed generator through a corresponding filter inductor, so as to implement power transmission with the rotor of the doubly-fed generator.
When the machine-side converter 101 is a three-phase converter, the specific structure thereof can be seen in fig. 5 or fig. 6. The machine-side converter 101 includes three-phase arm branches, and each arm is composed of two switching tubes connected in series. The middle point of each bridge arm, namely the connection point of the two switching tubes connected in series, is connected with the rotor of the doubly-fed generator through the corresponding filter inductor respectively. The switching tubes are switching tubes with anti-parallel diodes, and the specific mode of series connection between the two switching tubes is that the source electrode of one switching tube is connected with the drain electrode of the other switching tube.
The DC side of the machine-side converter 101, the DC side of the grid-side converter 102, the output side of the DC/DC conversion circuit 107, and both ends of the DC bus unit 103 are connected to a DC bus.
In practical applications, the DC bus unit 103 is generally disposed before the DC/DC conversion circuit 107 and the grid-side converter 102, that is, the machine-side converter 101 in the doubly-fed converter is connected to the DC bus unit 103, and then the DC/DC conversion circuit 107 and the grid-side converter 102 are connected, as shown in fig. 5 and fig. 6.
Specifically, the dc bus unit 103 includes: direct current bus capacitance and crowbar circuit. The direct-current bus capacitor and the crowbar circuit are connected in parallel between the positive electrode and the negative electrode of the direct-current bus.
The crowbar circuit is used for realizing the safe off-line of the doubly-fed generator when the power grid drops. This crowbar circuit includes: a resistor and a switching tube; one end of the resistor is connected with the anode of the direct current bus, the other end of the resistor is connected with the drain electrode of the switch tube, and the source electrode of the switch tube is connected with the cathode of the direct current bus. And a switch tube in the crowbar circuit is a switch tube with an anti-parallel diode.
It should be noted that, the grid-side converter 102 is similar to the machine-side converter 101, and is also a three-phase converter, and the specific structure thereof can also be referred to fig. 5 or fig. 6. Similarly, the grid-side converter 102 also includes three-phase arms, and each arm is also composed of two switching tubes connected in series. The middle point of each bridge arm, namely the connection point of the two switching tubes connected in series, is respectively connected with the power grid through the corresponding filtering branch. The switching tubes are switching tubes with anti-parallel diodes, the specific mode of series connection between two switching tubes is that the source electrode of one switching tube is connected with the drain electrode of the other switching tube, and the structure of the filtering branch can be seen in fig. 5 and 6.
The ac side of the grid-side converter 102 is connected to the grid via a second switching unit 105.
Specifically, the second switch unit 105 is used to control the on/off of the loop between the grid-side converter 102 and the grid.
The input side of the DC/DC conversion circuit 107 is connected to the photovoltaic array.
Specifically, the photovoltaic array is a photovoltaic array in a wind-solar hybrid power generation system; the DC/DC conversion circuit 107 connected to the photovoltaic array may receive the DC power output by the photovoltaic array.
The controller 106 is connected to the control terminals of the machine-side converter 101, the grid-side converter 102, the DC bus unit 103, the first switch unit 104, the second switch unit 105, and the DC/DC conversion circuit 107, respectively, and is configured to control the DC/DC conversion circuit 107 to output electric energy to the DC bus.
In practical application, the controller 106 controls the DC/DC conversion circuit 107 to receive the DC power output by the photovoltaic array through the input side thereof, and performs corresponding voltage conversion operation on the DC power through the DC/DC conversion circuit 107, so as to convert the DC power into a suitable form and merge the DC power into the DC bus; the electric energy can then be fully fed into the grid via the grid-side converter 102, or it can be fed into the grid via the grid-side converter 102 in part, and in part, provide the machine-side converter 101 with the required active power when the doubly-fed generator is at the sub-synchronous speed.
According to the double-fed converter provided by the embodiment, through the principle, in the actual operation process of a double-fed generator, the power margin of the grid-side converter 102 in the double-fed converter can be fully utilized, the energy output by the photovoltaic array is connected into the grid-side converter 102, the utilization rate of the power capacity of the grid-side converter 102 is improved, the simultaneous transmission of wind power generation and photovoltaic power generation is realized, and the hardware cost of a wind-solar hybrid power generation system is reduced. Moreover, the double-fed converter integrates the DC/DC conversion circuit 107 in the cabinet, so that the above functions can be realized without increasing the volume of the cabinet.
In practical applications, the DC/DC conversion circuit 107 may be a DC/DC boost circuit or a DC/DC buck-boost circuit.
If the DC/DC conversion circuit 107 is a DC/DC boost circuit, the specific composition and connection relationship of the circuit can be seen in fig. 6.
Specifically, the DC/DC boost circuit includes: a first diode Z, an inductor L and a switch tube S. Wherein, the switch tube S is a switch tube with an anti-parallel diode.
Furthermore, one end of the inductor L is connected to the drain of the switching tube S and the anode of the first diode Z, respectively, and the other end of the inductor L and the drain of the switching tube S are used as the input side of the DC/DC conversion circuit 107, that is, the other end of the inductor L and the source of the switching tube S are connected to the photovoltaic array; the source of the switching tube S and the cathode of the first diode Z serve as the output side of the DC/DC converter circuit 107, i.e., the source of the switching tube S and the cathode of the first diode Z are connected to the DC bus.
It should be noted that fig. 6 only shows a circuit structure of the DC/DC boost circuit, but in practical application, the specific structure of the DC/DC boost circuit may also be in other forms in the prior art, and therefore, details are not described again, and all of the structures belong to the protection scope of the present application. If the DC/DC conversion circuit 107 is a DC/DC buck-boost circuit, the specific structure of the DC/DC buck-boost circuit can be referred to in the prior art, and is not described herein again.
In this embodiment, the DC/DC conversion circuit 107 is specifically a DC/DC boost circuit, and the circuit structure is simple, so that on the basis of improving the utilization rate of the power capacity of the grid-side converter 102 and realizing simultaneous transmission of wind power generation and photovoltaic power generation, the hardware cost required by the doubly-fed converter can be further reduced by using the DC/DC boost circuit, that is, the hardware cost of the wind-solar hybrid power generation system is further reduced.
In another embodiment provided by the present application, on the basis of fig. 5, the controller 106 is further configured to:
(1) when the doubly-fed generator works in a sub-synchronous running state, the controller-side converter 101 receives and converts a part of electric energy on the direct-current bus and outputs the electric energy to a rotor of the doubly-fed generator, and the control grid-side converter 102 receives another part of electric energy on the direct-current bus to perform conversion grid connection.
Specifically, when the doubly-fed generator operates in a sub-synchronous state, that is, the rotor speed of the doubly-fed generator is less than the synchronous speed, the DC/DC conversion circuit 107 receives the electric energy output by the photovoltaic array, and supplies a part of the electric energy to the machine-side converter 101 for consuming functional energy, and the other part of the electric energy is connected to the grid through the grid-side converter 102.
(2) When the doubly-fed generator works in a synchronous running state, the control grid side converter 102 receives all electric energy on the direct current bus to carry out conversion grid connection.
Specifically, when the doubly-fed generator operates in a synchronous operation state, that is, when the rotor speed of the doubly-fed generator is equal to the synchronous speed, the machine-side converter 101 does not need to consume functional quantity, and the DC/DC conversion circuit 107 connects the electric energy output by the received photovoltaic array to the grid through the grid-side converter 102.
(3) When the doubly-fed generator works in a super-synchronous running state, the controller-side converter 101 receives rotor electric energy of the doubly-fed generator, converts the rotor electric energy and outputs the rotor electric energy to the direct-current bus, and meanwhile, the control grid-side converter 102 receives all electric energy on the direct-current bus to perform conversion grid connection.
Specifically, if the doubly-fed generator operates in the super-synchronous operation state, that is, the rotor speed of the doubly-fed generator is greater than the synchronous speed, the doubly-fed generator is connected to the grid through the grid-side converter 102 by the electric energy output by the machine-side converter 101 and the electric energy output by the photovoltaic array through the DC/DC conversion circuit 107. The power of the electric energy output by the photovoltaic array through the DC/DC conversion circuit 107 is as follows: the grid-side converter 102 transmits the capacity remaining after the power of the machine-side converter 101.
For economic reasons, in practical application, the capacity of the photovoltaic array can be set to be the rated slip power of the doubly-fed generator.
In this embodiment, the power margin of the grid-side converter 102 in the doubly-fed converter can be fully utilized according to the working state of the doubly-fed generator, and the energy output by the photovoltaic array is connected to the direct current side of the grid-side converter 102 in the doubly-fed converter, so that the hardware cost investment of the power generation equipment is reduced.
Optionally, referring to fig. 5 or fig. 6 as well, in another embodiment of the present application, a third switching unit 108 is further disposed on the power output circuit of the photovoltaic array.
Wherein a control terminal of the third switching unit 108 is connected to the controller 106. The on/off of each switch in the third switching unit 108 is controlled by the controller 106.
In practical applications, the third switching unit 108 may be connected between the photovoltaic array and the input side of the DC/DC conversion circuit 107, or between the output side of the DC/DC conversion circuit 107 and the direct current side of the grid-side converter 102, and the specific arrangement may depend on the application environment, and all of them belong to the protection scope of the present application.
When the doubly-fed generator works in a super-synchronous running state, and the electric energy output by the doubly-fed generator through the machine-side converter 101 is equal to the rated capacity of the grid-side converter 102, or when the photovoltaic array does not output electric energy, or when the doubly-fed converter is in a shutdown state, the controller 106 controls each switch in the third switch unit 108 to be in a shutdown state, so that the reliable disconnection of a loop between the photovoltaic array and the direct-current bus is ensured.
In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
It is further noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Claims (12)
1. A hybrid wind and solar power generation system, comprising: the double-fed generator comprises a double-fed generator, a photovoltaic array and a double-fed converter;
the double-fed generator is connected with a power grid through the double-fed converter;
the double-fed converter is internally provided with a DC/DC conversion circuit of which the output side is connected with a direct current bus, and the input side of the DC/DC conversion circuit is used for connecting the photovoltaic array;
the controller in the double-fed converter is used for outputting a PWM control signal to control the DC/DC conversion circuit to output electric energy to the direct-current bus, the power margin of a grid-side converter in the double-fed converter is fully utilized, and part or all of energy output by the photovoltaic array is connected to the grid-side converter, so that the utilization rate of the power capacity of the grid-side converter is improved; when all the energy output by the photovoltaic array is connected to the grid-side converter, the power of the electric energy output by the DC/DC conversion circuit is as follows: and the grid-side converter transmits the residual margin left after the power of the machine-side converter in the double-fed converter is transmitted.
2. The wind and solar hybrid power generation system according to claim 1, wherein the controller is configured to output a PWM control signal to control the DC/DC conversion circuit to output the electric energy to the DC bus, and specifically configured to:
determining an output power instruction value of a DC/DC conversion circuit in the doubly-fed converter according to an active current given value of a grid-side converter in the doubly-fed converter;
and generating a corresponding PWM signal according to the output power instruction value of the DC/DC conversion circuit, and outputting the PWM signal to the control end of the DC/DC conversion circuit.
3. The wind and solar hybrid power generation system according to claim 2, wherein the controller is configured to, when determining the output power command value of the DC/DC conversion circuit in the doubly-fed converter according to the active current set value of the grid-side converter in the doubly-fed converter, specifically:
if the active current given value of the grid-side converter is smaller than or equal to a first preset value, determining that the output power instruction value of the DC/DC conversion circuit is the power value of the maximum power point;
if the given value of the active current of the grid-side converter is larger than or equal to a second preset value, judging that the DC/DC conversion circuit enters a limiting MPPT state, and determining that the output power instruction value of the DC/DC conversion circuit is the power value before the DC/DC conversion circuit enters the limiting MPPT state;
and if the given value of the active current of the grid-side converter is greater than or equal to a third preset value, determining that the output power instruction value of the DC/DC conversion circuit is a power value which is gradually reduced according to a preset step length.
4. The hybrid wind-solar power generation system according to claim 3, wherein the first preset value is
The second preset value is
The third preset value is
Wherein, K1A first hysteresis value, K, of a rated current utilization factor of the grid-side converter2A second hysteresis value, K, of the rated current utilization factor of the grid-side converter3A third hysteresis value, I, of the rated current utilization factor of the grid-side converterrateRepresents the maximum current, I, of the grid-side converter in steady-state operationq_refRepresenting a reactive current setpoint of the grid-side converter.
5. The wind-solar hybrid power generation system according to claim 3, wherein the generating of the corresponding PWM signal according to the output power command value of the DC/DC conversion circuit is specifically configured to:
determining a working current instruction value of the DC/DC conversion circuit according to the output power instruction value of the DC/DC conversion circuit;
calculating to obtain a difference value of subtracting a working current feedback value from a working current instruction value of the DC/DC conversion circuit;
and performing PI regulation on the difference value to generate the PWM signal.
6. The hybrid wind-solar power generation system according to any one of claims 1 to 5, wherein the capacity of the photovoltaic array is the rated slip power of the doubly fed generator.
7. The wind and solar hybrid power system according to any one of claims 1 to 5, wherein the doubly fed converter comprises: the controller comprises a machine side converter, a grid side converter, a direct current bus unit, a first switch unit, a second switch unit, a controller and a DC/DC conversion circuit; wherein the content of the first and second substances,
the first switch unit is connected between the stator of the doubly-fed generator and a power grid;
the alternating current side of the machine side converter is connected with the rotor of the doubly-fed generator;
the direct current side of the machine side converter, the direct current side of the grid side converter, the output side of the DC/DC conversion circuit and two ends of the direct current bus unit are connected with a direct current bus;
the alternating current side of the grid-side converter is connected with a power grid through the second switch unit;
the controller is respectively connected with the machine side converter, the grid side converter, the direct current bus unit, the first switch unit, the second switch unit and the control end of the DC/DC conversion circuit, and is further used for controlling the machine side converter and the grid side converter to work in corresponding states.
8. The wind-solar hybrid power generation system according to claim 7, wherein the controller is configured to control the machine-side converter and the grid-side converter to operate in corresponding states, and is specifically configured to:
when the doubly-fed generator works in a sub-synchronous running state, the machine side converter is controlled to receive part of electric energy on the direct-current bus, convert the electric energy and output the converted electric energy to a rotor of the doubly-fed generator, and meanwhile, the grid side converter is controlled to receive the other part of electric energy on the direct-current bus, convert and grid-connect;
when the doubly-fed generator works in a synchronous running state, controlling the grid-side converter to receive all electric energy on the direct-current bus to carry out conversion grid connection;
when the doubly-fed generator works in a super-synchronous running state, the machine side converter is controlled to receive rotor electric energy of the doubly-fed generator, convert the rotor electric energy and output the converted rotor electric energy to the direct-current bus, and meanwhile, the grid side converter is controlled to receive all electric energy on the direct-current bus to convert and grid the direct-current bus.
9. The wind and solar hybrid power generation system of claim 7, wherein the doubly fed converter further comprises: the third switching unit is arranged on the electric energy output loop of the photovoltaic array; and the control end of the third switching unit is connected with the controller.
10. The wind-solar hybrid power generation system according to claim 7, wherein the DC/DC conversion circuit is: a DC/DC boost circuit, or a DC/DC buck-boost circuit.
11. The hybrid wind-solar power generation system according to claim 7, wherein the dc bus unit comprises: a DC bus capacitor and a crowbar circuit;
and the direct current bus capacitor is connected with the crowbar circuit in parallel.
12. The wind and solar hybrid power generation system of claim 11, wherein the crowbar circuit comprises: a resistor and a switching tube;
one end of the resistor is connected with the anode of the direct current bus, the other end of the resistor is connected with the drain electrode of the switch tube, and the source electrode of the switch tube is connected with the cathode of the direct current bus.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911052677.9A CN110729760B (en) | 2019-10-31 | 2019-10-31 | Wind-solar hybrid power generation system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911052677.9A CN110729760B (en) | 2019-10-31 | 2019-10-31 | Wind-solar hybrid power generation system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110729760A CN110729760A (en) | 2020-01-24 |
| CN110729760B true CN110729760B (en) | 2021-12-10 |
Family
ID=69223509
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911052677.9A Active CN110729760B (en) | 2019-10-31 | 2019-10-31 | Wind-solar hybrid power generation system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110729760B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101017982A (en) * | 2007-03-12 | 2007-08-15 | 刘建政 | Light voltage and wind power integrated networking device with the reactive power compensation and harmonious administration function |
| CN102570503A (en) * | 2011-12-30 | 2012-07-11 | 东方电气集团东方汽轮机有限公司 | Double-fed wind power generation system |
| CN104868498A (en) * | 2015-06-05 | 2015-08-26 | 江苏同芯电气科技有限公司 | Topological structure for wind-solar integrated large-power grid-connected converter system |
| CN105680771A (en) * | 2016-03-25 | 2016-06-15 | 南通大学 | Wind-solar complementary generation system and control method |
| WO2017056114A1 (en) * | 2015-10-01 | 2017-04-06 | Regen Powertech Private Limited | Wind-solar hybrid power generation system and method |
| US9793788B2 (en) * | 2013-12-20 | 2017-10-17 | General Electric Company | Energy storage system for renewable energy source |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN205141698U (en) * | 2015-09-29 | 2016-04-06 | 三一重型能源装备有限公司 | Double -fed wind generator system |
| CN109103925B (en) * | 2018-07-31 | 2022-01-28 | 国网江苏省电力有限公司淮安供电分公司 | Photovoltaic power generation-based microgrid |
-
2019
- 2019-10-31 CN CN201911052677.9A patent/CN110729760B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101017982A (en) * | 2007-03-12 | 2007-08-15 | 刘建政 | Light voltage and wind power integrated networking device with the reactive power compensation and harmonious administration function |
| CN102570503A (en) * | 2011-12-30 | 2012-07-11 | 东方电气集团东方汽轮机有限公司 | Double-fed wind power generation system |
| US9793788B2 (en) * | 2013-12-20 | 2017-10-17 | General Electric Company | Energy storage system for renewable energy source |
| CN104868498A (en) * | 2015-06-05 | 2015-08-26 | 江苏同芯电气科技有限公司 | Topological structure for wind-solar integrated large-power grid-connected converter system |
| WO2017056114A1 (en) * | 2015-10-01 | 2017-04-06 | Regen Powertech Private Limited | Wind-solar hybrid power generation system and method |
| CN105680771A (en) * | 2016-03-25 | 2016-06-15 | 南通大学 | Wind-solar complementary generation system and control method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110729760A (en) | 2020-01-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112736977B (en) | Multi-terminal offshore wind power flexible direct current and energy storage cooperative grid-connected system and control method thereof | |
| CN112290583B (en) | DC coupling off-grid hydrogen production system and control cabinet power supply device and control method thereof | |
| CN107181274B (en) | Method for accessing new energy into flexible direct current power grid | |
| CN112803472A (en) | Direct-current coupling hydrogen production system and control method thereof | |
| US10211721B2 (en) | DC/AC converter apparatus comprising means for controlling the reactive power and power conversion and generation system comprising such DC/AC converter apparatus | |
| CN112290582B (en) | New energy power station and direct current coupling off-grid hydrogen production system and control method thereof | |
| CN112736968A (en) | New energy hydrogen production system and control method thereof | |
| WO2011087783A2 (en) | Ac diversion mode controller | |
| CN112491032A (en) | Direct-current coupling off-grid hydrogen production system and control method thereof | |
| CN112290579A (en) | Direct-current coupling off-grid hydrogen production system and control method thereof | |
| CN112366748A (en) | Wind storage combined wind power converter and control method thereof | |
| CN115765028A (en) | Wind, light and water storage direct current collection synchronous motor grid-connected system and application method thereof | |
| Korada et al. | Dynamic energy management in DC microgrid using composite energy storage system | |
| CN110350573B (en) | Self-healing power supply system and control method | |
| CN112290580A (en) | New energy hydrogen production system | |
| CN112217193B (en) | Photovoltaic hydrogen production power station, direct-current coupling photovoltaic off-grid hydrogen production system and control method thereof | |
| CN105207270B (en) | Improve the inverter power control method for coordinating of grid-connected voltage out-of-limit | |
| CN110729760B (en) | Wind-solar hybrid power generation system | |
| Singh et al. | A review on power quality enhanced converter of permanent magnet synchronous wind generator | |
| Letting et al. | Dynamic performance analysis of an integrated wind-photovoltaic microgrid with storage | |
| Bubalo et al. | Optimized isolated operation of a WECS-powered microgrid with a battery-assisted qZSI | |
| CN112909988B (en) | Off-grid doubly-fed wind turbine generator system power generation system, hydrogen production system and control method thereof | |
| CN111900749B (en) | Network source coordination virtual synchronous machine control method of optical storage integrated system | |
| CN110224389B (en) | Direct current micro-grid system based on self-discipline floating voltage operation strategy | |
| Behera et al. | DC microgrid management using power electronics converters |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |