DFIG current-limiting and field-extinguishing control method and system
阅读说明：本技术 一种dfig限流灭磁控制方法及系统 (DFIG current-limiting and field-extinguishing control method and system ) 是由 秦世耀 贺敬 李少林 年珩 张金平 张梅 童豪 苗风麟 于 2021-01-06 设计创作，主要内容包括：本发明涉及一种DFIG限流灭磁控制方法及系统,包括：获取电网电压跌落时电网与DFIG发电系统的运行参数,根据电网电压跌落时电网与DFIG发电系统的运行参数确定DFIG发电系统的输出数据,根据DFIG发电系统的输出数据确定DFIG转子电压补偿量、DFIG转子电压灭磁分量、转子电压矢量和电压解耦项,根据DFIG转子电压补偿量、DFIG转子电压灭磁分量、转子电压矢量和电压解耦项确定DFIG转子电压参考值,基于DFIG转子电压参考值对DFIG转子变流器中的功率开关器件进行控制。本发明提供的技术方案有效地抑制了电网电压跌落瞬间转子冲击电流,加快了定子暂态磁链的衰减速度,进而提高了控制系统的可靠性。(The invention relates to a DFIG current-limiting and field-suppression control method and a DFIG current-limiting and field-suppression control system, wherein the DFIG current-limiting and field-suppression control method comprises the following steps: the method comprises the steps of obtaining operation parameters of a power grid and a DFIG power generation system when the voltage of the power grid drops, determining output data of the DFIG power generation system according to the operation parameters of the power grid and the DFIG power generation system when the voltage of the power grid drops, determining a DFIG rotor voltage compensation quantity, a DFIG rotor voltage demagnetization component, a rotor voltage vector and a voltage decoupling item according to the output data of the DFIG power generation system, determining a DFIG rotor voltage reference value according to the DFIG rotor voltage compensation quantity, the DFIG rotor voltage demagnetization component, the rotor voltage vector and the voltage decoupling item, and controlling a power switch device in a DFIG rotor converter based on the DFIG rotor voltage reference value. The technical scheme provided by the invention effectively inhibits the rotor impact current at the moment of power grid voltage drop, accelerates the attenuation speed of the transient magnetic linkage of the stator, and further improves the reliability of a control system.)
1. A DFIG current-limiting and de-excitation control method is characterized by comprising the following steps:
acquiring operation parameters of a power grid and a DFIG power generation system when the voltage of the power grid drops;
determining output data of the DFIG power generation system according to the operation parameters of the grid and the DFIG power generation system when the grid voltage drops;
determining a DFIG rotor voltage compensation quantity, a DFIG rotor voltage de-excitation component, a rotor voltage vector and a voltage decoupling term according to output data of the DFIG power generation system;
determining a DFIG rotor voltage reference value according to the DFIG rotor voltage compensation quantity, the DFIG rotor voltage de-excitation component, the rotor voltage vector and the voltage decoupling term;
and controlling the power switch device in the DFIG rotor converter based on the DFIG rotor voltage reference value.
2. The method of claim 1, wherein the operating parameters comprise: the system comprises a power grid voltage vector, a stator current vector and a rotor current vector, a stator voltage d-axis component, a stator voltage q-axis component, a stator three-phase current d-axis component, a stator three-phase current q-axis component, an active component of power grid current, a current limiting value of a converter, a stator voltage amplitude, a stator voltage rated value, a power grid line equivalent reactance, a power grid line equivalent resistance and a reactive current reference value of a power grid.
3. The method of claim 1, wherein outputting the data comprises: the active power output by the DFIG stator side, the reactive power reference value required to be sent out by the DFIG unit, the active power reference value required to be sent out by the DFIG unit, the stator flux linkage and the rotor rotation speed angular frequency.
4. The method of claim 3, wherein the active power P output by the DFIG stator sidesIs calculated as follows:
the active power Q output by the DFIG stator sidesIs calculated as follows:
in the above formula, usdIs the d-axis component of the stator voltage, usqIs a stator voltage q-axis component, isdIs d-axis component, i, of stator three-phase currentsqIs the q-axis component of the three-phase current of the stator.
5. The method of claim 3, wherein the step of determining the target value is performed in a batch processAnd the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value P required to be sent by the DFIG units *Is calculated as follows:
Ps *＝Ps
when in useWhen, ifThe reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value P required to be sent by the DFIG units *Is calculated as follows:
Ps *＝0
otherwise, the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value P required to be sent by the DFIG units *Is calculated as follows:
in the above formula, IpBeing the active component of the grid current, IqBeing a reactive component of the grid current, IsNFor current limiting value, V, of the convertersNFor stator voltage rating, XgFor equivalent reactance of the grid line, ZgAs the line impedance of the grid, RgFor line equivalent resistance, V, of the networksIs the stator voltage amplitude, PsFor active power, V, output from the stator side of the DFIGgFor the amplitude of the voltage of the power network,is the reactive current reference value of the power grid.
6. Method according to claim 3, characterized in that the stator flux linkage ψsdqIs calculated as follows:
in the above formula, UsdqAnd (t) is a stator voltage vector at the time t.
7. A method according to claim 3, wherein said rotor speed angular frequency ωrIs calculated as follows:
in the above equation, θ is a coordinate transformation phase angle.
8. The method of claim 3, wherein determining the DFIG rotor voltage compensation amount, the DFIG rotor voltage field suppression component, the rotor voltage vector, and the voltage decoupling term from the output data of the DFIG power generation system comprises:
determining a rotor voltage vector according to active power and reactive power output by the stator side of the DFIG and an active power reference value and a reactive power reference value required to be sent by the DFIG unit;
determining a rotor voltage compensation quantity according to the rotor current vector;
determining a voltage decoupling term according to the stator flux linkage;
and determining a rotor voltage de-excitation component according to the rotor current vector and the stator current vector.
9. The method of claim 8, wherein the rotor voltage vectorIs calculated as follows:
in the above formula, KpFor a given proportionality coefficient, KiFor a given integral coefficient, j is an imaginary unit, Ps *The active power reference value required to be sent out by the DFIG unit,reference value of reactive power, P, required to be emitted by DFIG unitsFor active power, Q, output from the stator side of the DFIGsThe active power output by the stator side of the DFIG.
10. The method of claim 8, wherein the rotor voltage compensation amountIs calculated as follows:
in the above formula, RvVirtual resistance, I, preset for DFIG power generation systemsrdqIs the rotor current vector.
11. The method of claim 8, wherein the voltage decoupling term ErdqIs calculated as follows:
in the above formula, RrIs rotor resistance, LmFor stator-rotor mutual inductance,. psisdqIs stator flux linkage, j is an imaginary unit, ωs＝ω1-ωr，ωsIs the angular frequency of rotation difference, omegarIs the angular frequency, omega, of the rotor speed1＝100πrad/s，ω1To fix the angular frequency of rotation, LrFor equivalent self-inductance of rotor winding，LmIs the stator-rotor mutual inductance of the DFIG.
12. The method of claim 8, wherein determining a rotor voltage field suppression component from the rotor current vector comprises:
calculating a DFIG rotor current reference vector according to the DFIG stator current vector;
and substituting the difference value of the DFIG rotor current reference vector and the DFIG rotor current vector into the resonance controller to obtain a DFIG rotor voltage demagnetization component.
13. The method of claim 12, wherein the DFIG rotor current reference vectorIs calculated as follows:
in the above formula, k coefficient of demagnetization, IsdqIs the DFIG stator current vector.
14. The method of claim 1, wherein the DFIG rotor voltage reference valueIs calculated as follows:
in the above formula, ErdqFor voltage decoupling terms, UsdqIs a stator voltage vector, VSIn order to be the stator voltage amplitude,to be the rotor voltage vector,the rotor voltage field suppression component.
15. The method of claim 1, wherein controlling power switching devices in the DFIG rotor converter based on the DFIG rotor voltage reference comprises:
conversion of phase angle theta to DFIG rotor voltage reference value by virtual coordinatePerforming coordinate transformation to obtain the DFIG rotor voltage reference value under the alpha-beta coordinate system
Will be described inThe SVPWM module is used as the input of the SVPWM module to obtain a switching tube driving signal of the rotor converter output by the SVPWM module;
and controlling a power switch device in the DFIG rotor converter by using the switch tube driving signal.
16. The method of claim 15, wherein the DFIG rotor voltage reference in the α β coordinate systemIs calculated as follows:
in the above formula, the first and second carbon atoms are,for DFIG rotor voltage referenceThe d-axis component of (a) is,for DFIG rotor voltage referenceθ is a virtual coordinate transformation phase angle.
17. A DFIG current-limiting demagnetization control system, the system comprising:
the acquisition module is used for acquiring the operating parameters of a power grid and the DFIG power generation system when the voltage of the power grid drops;
the first determining module is used for determining output data of the DFIG power generation system according to the operation parameters of the grid and the DFIG power generation system when the grid voltage drops;
the second determination module is used for determining a DFIG rotor voltage compensation quantity, a DFIG rotor voltage field suppression component, a rotor voltage vector and a voltage decoupling item according to output data of the DFIG power generation system;
the third determining module is used for determining a DFIG rotor voltage reference value according to the DFIG rotor voltage compensation quantity, the DFIG rotor voltage field suppression component, the rotor voltage vector and the voltage decoupling item;
and the control module is used for controlling the power switching device in the DFIG rotor converter based on the DFIG rotor voltage reference value.
18. The system of claim 17, wherein the operating parameters comprise: the system comprises a power grid voltage vector, a stator current vector and a rotor current vector, a stator voltage d-axis component, a stator voltage q-axis component, a stator three-phase current d-axis component, a stator three-phase current q-axis component, an active component of power grid current, a current limiting value of a converter, a stator voltage amplitude, a stator voltage rated value, a power grid line equivalent reactance, a power grid line equivalent resistance and a reactive current reference value of a power grid.
19. The system of claim 17, wherein the outputting data comprises: the active power output by the DFIG stator side, the reactive power reference value required to be sent out by the DFIG unit, the active power reference value required to be sent out by the DFIG unit, the stator flux linkage and the rotor rotation speed angular frequency.
20. The system of claim 19, wherein the active power P output by the DFIG stator side is activesIs calculated as follows:
the active power Q output by the DFIG stator sidesIs calculated as follows:
in the above formula, usdIs the d-axis component of the stator voltage, usqIs a stator voltage q-axis component, isdIs d-axis component, i, of stator three-phase currentsqIs the q-axis component of the three-phase current of the stator.
21. The system of claim 19, wherein the system is characterized by the fact thatAnd the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value P required to be sent by the DFIG units *Is calculated as follows:
Ps *＝Ps
when in useWhen, ifThe reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value P required to be sent by the DFIG units *Is calculated as follows:
Ps *＝0
otherwise, the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value P required to be sent by the DFIG units *Is calculated as follows:
in the above formula, IpBeing the active component of the grid current, IqBeing a reactive component of the grid current, IsNFor current limiting value, V, of the convertersNFor stator voltage rating, XgFor equivalent reactance of the grid line, ZgAs the line impedance of the grid, RgFor line equivalent resistance, V, of the networksIs the stator voltage amplitude, PsFor active power, V, output from the stator side of the DFIGgFor the amplitude of the voltage of the power network,is the reactive current reference value of the power grid.
22. The system of claim 19, wherein the stator flux linkage ψsdqIs calculated as follows:
in the above formula, UsdqAnd (t) is a stator voltage vector at the time t.
23. The system of claim 19, wherein the rotor speed angular frequency ω isrIs calculated as follows:
in the above equation, θ is a coordinate transformation phase angle.
24. The system of claim 19, wherein the second determination module comprises:
the first determining unit is used for determining a rotor voltage vector according to active power and reactive power output by the DFIG stator side and an active power reference value and a reactive power reference value required to be sent by the DFIG unit;
the second determining unit is used for determining a rotor voltage compensation quantity according to the rotor current vector;
the third determining unit is used for determining a voltage decoupling term according to the stator flux linkage;
and the fourth determining unit is used for determining the rotor voltage de-excitation component according to the rotor current vector and the stator current vector.
25. The system of claim 24, wherein the rotor voltage vectorIs calculated as follows:
in the above formula, KpFor a given proportionality coefficient, KiFor a given integral coefficient, j is an imaginary unit, Ps *The active power reference value required to be sent out by the DFIG unit,reference value of reactive power, P, required to be emitted by DFIG unitsFor active power, Q, output from the stator side of the DFIGsThe active power output by the stator side of the DFIG.
26. The system of claim 24, wherein the rotor voltage offset amountIs calculated as follows:
in the above formula, RvVirtual preset for DFIG power generation systemPseudo-resistor, IrdqIs the rotor current vector.
27. The system of claim 24, wherein the voltage decoupling term ErdqIs calculated as follows:
in the above formula, RrIs rotor resistance, LmFor stator-rotor mutual inductance,. psisdqIs stator flux linkage, j is an imaginary unit, ωs＝ω1-ωr，ωsIs the angular frequency of rotation difference, omegarIs the angular frequency, omega, of the rotor speed1＝100πrad/s，ω1To fix the angular frequency of rotation, LrFor equivalent self-inductance of the rotor winding, LmIs the stator-rotor mutual inductance of the DFIG.
28. The system of claim 24, wherein said determining a rotor voltage field suppression component from a rotor current vector comprises:
calculating a DFIG rotor current reference vector according to the DFIG stator current vector;
and substituting the difference value of the DFIG rotor current reference vector and the DFIG rotor current vector into the resonance controller to obtain a DFIG rotor voltage demagnetization component.
29. The system of claim 28, wherein the DFIG rotor current reference vectorIs calculated as follows:
in the above formula, k coefficient of demagnetization, IsdqIs the DFIG stator current vector.
30. The system of claim 17, wherein the DFIG rotor voltage reference valueIs calculated as follows:
in the above formula, ErdqFor voltage decoupling terms, UsdqIs a stator voltage vector, VSIn order to be the stator voltage amplitude,to be the rotor voltage vector,the rotor voltage field suppression component.
31. The system of claim 17, wherein the control module comprises:
an acquisition unit for converting the phase angle theta to DFIG rotor voltage reference value by virtual coordinatePerforming coordinate transformation to obtain the DFIG rotor voltage reference value under the alpha-beta coordinate system
An output unit for outputting the aboveThe SVPWM module is used as the input of the SVPWM module to obtain a switching tube driving signal of the rotor converter output by the SVPWM module;
and the control unit is used for controlling a power switch device in the DFIG rotor converter by utilizing the switch tube driving signal.
32. The system of claim 31, wherein the DFIG rotor voltage reference in the α β coordinate systemIs calculated as follows:
in the above formula, the first and second carbon atoms are,for DFIG rotor voltage referenceThe d-axis component of (a) is,for DFIG rotor voltage referenceθ is a virtual coordinate transformation phase angle.
Technical Field
The invention relates to the field of motor control, in particular to a DFIG current-limiting and de-excitation control method and system.
Background
Because a doubly-fed induction generator (DFIG) converter is small in capacity and flexible and adjustable in power, the proportion of a wind power generation system based on the DFIG in new energy power generation is larger and larger. However, most of the existing wind farms are distributed in remote areas, so that long transmission lines are needed, and line impedance is not negligible, so that the existing wind farms usually have the characteristic of a weak power grid.
Under the non-ideal grid condition of the current DFIG control, such as under the conditions of sudden voltage change or sudden frequency change, the control of the DFIG cannot acquire a grid voltage signal quickly and accurately, and meanwhile, sudden voltage drop is the problem that the generated large rotor rush current and transient magnetic linkage are slowly attenuated, so that certain harm is brought to a motor and equipment, the accuracy of subsequent DFIG control is influenced, and a potential stability problem can be caused.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a DFIG current-limiting and field-extinguishing control method and a DFIG current-limiting and field-extinguishing control system.
The purpose of the invention is realized by adopting the following technical scheme:
the invention provides a DFIG current-limiting and field-extinguishing control method, which is improved in that the method comprises the following steps:
acquiring operation parameters of a power grid and a DFIG power generation system when the voltage of the power grid drops;
determining output data of the DFIG power generation system according to the operation parameters of the grid and the DFIG power generation system when the grid voltage drops;
determining a DFIG rotor voltage compensation quantity, a DFIG rotor voltage de-excitation component, a rotor voltage vector and a voltage decoupling term according to output data of the DFIG power generation system;
determining a DFIG rotor voltage reference value according to the DFIG rotor voltage compensation quantity, the DFIG rotor voltage de-excitation component, the rotor voltage vector and the voltage decoupling term;
and controlling the power switch device in the DFIG rotor converter based on the DFIG rotor voltage reference value.
Preferably, the operating parameters include: the system comprises a power grid voltage vector, a stator current vector and a rotor current vector, a stator voltage d-axis component, a stator voltage q-axis component, a stator three-phase current d-axis component, a stator three-phase current q-axis component, an active component of power grid current, a current limiting value of a converter, a stator voltage amplitude, a stator voltage rated value, a power grid line equivalent reactance, a power grid line equivalent resistance and a reactive current reference value of a power grid.
Preferably, the output data includes: the active power output by the DFIG stator side, the reactive power reference value required to be sent out by the DFIG unit, the active power reference value required to be sent out by the DFIG unit, the stator flux linkage and the rotor rotation speed angular frequency.
Further, the active power P output by the stator side of the DFIGsIs calculated as follows:
the active power Q output by the DFIG stator sidesIs calculated as follows:
in the above formula, usdIs the d-axis component of the stator voltage, usqIs a stator voltage q-axis component, isdIs d-axis component, i, of stator three-phase currentsqIs the q-axis component of the three-phase current of the stator.
Further, whenAnd the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
when in useWhen, ifThe reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
otherwise, the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
in the above formula, IpBeing the active component of the grid current, IqBeing a reactive component of the grid current, IsNFor current limiting value, V, of the convertersNFor stator voltage rating, XgFor equivalent reactance of the grid line, ZgAs the line impedance of the grid, RgFor line equivalent resistance, V, of the networksIs the stator voltage amplitude, PsFor active power, V, output from the stator side of the DFIGgFor the amplitude of the voltage of the power network,is the reactive current reference value of the power grid.
Further, the stator flux linkage psisdqIs calculated as follows:
in the above formula, UsdqAnd (t) is a stator voltage vector at the time t.
Further, the rotor speed angular frequency ωrIs calculated as follows:
in the above equation, θ is a coordinate transformation phase angle.
Further, the determining of the DFIG rotor voltage compensation amount, the DFIG rotor voltage field suppression component, the rotor voltage vector and the voltage decoupling term according to the output data of the DFIG power generation system includes:
determining a rotor voltage vector according to active power and reactive power output by the stator side of the DFIG and an active power reference value and a reactive power reference value required to be sent by the DFIG unit;
determining a rotor voltage compensation quantity according to the rotor current vector;
determining a voltage decoupling term according to the stator flux linkage;
and determining a rotor voltage de-excitation component according to the rotor current vector and the stator current vector.
Further, the rotor voltage vectorIs calculated as follows:
in the above formula, KpFor a given proportionality coefficient, KiFor a given integration coefficient, j is the unit of an imaginary number,the active power reference value required to be sent out by the DFIG unit,reference value of reactive power, P, required to be emitted by DFIG unitsFor active power, Q, output from the stator side of the DFIGsThe active power output by the stator side of the DFIG.
Further, the rotor voltage compensation amountIs calculated as follows:
in the above formula, RvVirtual resistance, I, preset for DFIG power generation systemsrdqIs the rotor current vector.
Further, the voltage decoupling term ErdqIs calculated as follows:
in the above formula, RrIs rotor resistance, LmFor stator-rotor mutual inductance,. psisdqIs stator flux linkage, j is an imaginary unit, ωs＝ω1-ωr，ωsIs the angular frequency of rotation difference, omegarIs the angular frequency, omega, of the rotor speed1＝100πrad/s，ω1To fix the angular frequency of rotation, LrFor equivalent self-inductance of the rotor winding, LmIs the stator-rotor mutual inductance of the DFIG.
Further, the determining the rotor voltage de-excitation component according to the rotor current vector includes:
calculating a DFIG rotor current reference vector according to the DFIG stator current vector;
and substituting the difference value of the DFIG rotor current reference vector and the DFIG rotor current vector into the resonance controller to obtain a DFIG rotor voltage demagnetization component.
Further, the DFIG rotor current reference vectorIs calculated as follows:
in the above formula, k coefficient of demagnetization, IsdqIs the DFIG stator current vector.
Preferably, the DFIG rotor voltage reference valueIs calculated as follows:
in the above formula, ErdqFor voltage decoupling terms, UsdqIs a stator voltage vector, VSIn order to be the stator voltage amplitude,to be the rotor voltage vector,the rotor voltage field suppression component.
Preferably, the controlling the power switching device in the DFIG rotor converter based on the DFIG rotor voltage reference value includes:
conversion of phase angle theta to DFIG rotor voltage reference value by virtual coordinatePerforming coordinate transformation to obtain the DFIG rotor voltage reference value under the alpha-beta coordinate system
Will be described inThe SVPWM module is used as the input of the SVPWM module to obtain a switching tube driving signal of the rotor converter output by the SVPWM module;
and controlling a power switch device in the DFIG rotor converter by using the switch tube driving signal.
Further, the DFIG rotor voltage reference value under the alpha and beta coordinate systemIs calculated as follows:
in the above formula, the first and second carbon atoms are,for DFIG rotor voltage referenceThe d-axis component of (a) is,for DFIG rotor voltage referenceθ is a virtual coordinate transformation phase angle.
The invention provides a DFIG current-limiting and field-extinguishing control system, and the improvement is that the system comprises:
the acquisition module is used for acquiring the operating parameters of a power grid and the DFIG power generation system when the voltage of the power grid drops;
the first determining module is used for determining output data of the DFIG power generation system according to the operation parameters of the grid and the DFIG power generation system when the grid voltage drops;
the second determination module is used for determining a DFIG rotor voltage compensation quantity, a DFIG rotor voltage field suppression component, a rotor voltage vector and a voltage decoupling item according to output data of the DFIG power generation system;
the third determining module is used for determining a DFIG rotor voltage reference value according to the DFIG rotor voltage compensation quantity, the DFIG rotor voltage field suppression component, the rotor voltage vector and the voltage decoupling item;
and the control module is used for controlling the power switching device in the DFIG rotor converter based on the DFIG rotor voltage reference value.
Preferably, the operating parameters include: the system comprises a power grid voltage vector, a stator current vector and a rotor current vector, a stator voltage d-axis component, a stator voltage q-axis component, a stator three-phase current d-axis component, a stator three-phase current q-axis component, an active component of power grid current, a current limiting value of a converter, a stator voltage amplitude, a stator voltage rated value, a power grid line equivalent reactance, a power grid line equivalent resistance and a reactive current reference value of a power grid.
Preferably, the output data includes: the active power output by the DFIG stator side, the reactive power reference value required to be sent out by the DFIG unit, the active power reference value required to be sent out by the DFIG unit, the stator flux linkage and the rotor rotation speed angular frequency.
Further, the active power P output by the stator side of the DFIGsIs calculated as follows:
the active power Q output by the DFIG stator sidesIs calculated as follows:
in the above formula, usdIs the d-axis component of the stator voltage, usqIs a stator voltage q-axis component, isdIs d-axis component, i, of stator three-phase currentsqIs the q-axis component of the three-phase current of the stator.
Further, whenAnd the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
when in useWhen, ifThe reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
otherwise, the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
in the above formula, IpBeing the active component of the grid current, IqBeing a reactive component of the grid current, IsNFor current limiting value, V, of the convertersNFor stator voltage rating, XgFor mains lines, etcEffective reactance, ZgAs the line impedance of the grid, RgFor line equivalent resistance, V, of the networksIs the stator voltage amplitude, PsFor active power, V, output from the stator side of the DFIGgFor the amplitude of the voltage of the power network,is the reactive current reference value of the power grid.
Further, the stator flux linkage psisdqIs calculated as follows:
in the above formula, UsdqAnd (t) is a stator voltage vector at the time t.
Further, the rotor speed angular frequency ωrIs calculated as follows:
in the above equation, θ is a coordinate transformation phase angle.
Further, the second determining module includes:
the first determining unit is used for determining a rotor voltage vector according to active power and reactive power output by the DFIG stator side and an active power reference value and a reactive power reference value required to be sent by the DFIG unit;
the second determining unit is used for determining a rotor voltage compensation quantity according to the rotor current vector;
the third determining unit is used for determining a voltage decoupling term according to the stator flux linkage;
and the fourth determining unit is used for determining the rotor voltage de-excitation component according to the rotor current vector and the stator current vector.
Further, the rotor voltage vectorIs calculated byThe following were used:
in the above formula, KpFor a given proportionality coefficient, KiFor a given integration coefficient, j is the unit of an imaginary number,the active power reference value required to be sent out by the DFIG unit,reference value of reactive power, P, required to be emitted by DFIG unitsFor active power, Q, output from the stator side of the DFIGsThe active power output by the stator side of the DFIG.
Further, the rotor voltage compensation amountIs calculated as follows:
in the above formula, RvVirtual resistance, I, preset for DFIG power generation systemsrdqIs the rotor current vector.
Further, the voltage decoupling term ErdqIs calculated as follows:
in the above formula, RrIs rotor resistance, LmFor stator-rotor mutual inductance,. psisdqIs stator flux linkage, j is an imaginary unit, ωs＝ω1-ωr，ωsIs the angular frequency of rotation difference, omegarIs the angular frequency, omega, of the rotor speed1＝100πrad/s，ω1To fix the angular frequency of rotation, LrFor equivalent self-inductance of the rotor winding, LmIs the stator-rotor mutual inductance of the DFIG.
Further, the determining the rotor voltage de-excitation component according to the rotor current vector includes:
calculating a DFIG rotor current reference vector according to the DFIG stator current vector;
and substituting the difference value of the DFIG rotor current reference vector and the DFIG rotor current vector into the resonance controller to obtain a DFIG rotor voltage demagnetization component.
Further, the DFIG rotor current reference vectorIs calculated as follows:
in the above formula, k coefficient of demagnetization, IsdqIs the DFIG stator current vector.
Preferably, the DFIG rotor voltage reference valueIs calculated as follows:
in the above formula, ErdqFor voltage decoupling terms, UsdqIs a stator voltage vector, VSIn order to be the stator voltage amplitude,to be the rotor voltage vector,the rotor voltage field suppression component.
Preferably, the control module includes:
an acquisition unit for utilizing the virtualCoordinate transformation phase angle theta to DFIG rotor voltage reference valuePerforming coordinate transformation to obtain the DFIG rotor voltage reference value under the alpha-beta coordinate system
An output unit for outputting the aboveThe SVPWM module is used as the input of the SVPWM module to obtain a switching tube driving signal of the rotor converter output by the SVPWM module;
and the control unit is used for controlling a power switch device in the DFIG rotor converter by utilizing the switch tube driving signal.
Further, the DFIG rotor voltage reference value under the alpha and beta coordinate systemIs calculated as follows:
in the above formula, the first and second carbon atoms are,for DFIG rotor voltage referenceThe d-axis component of (a) is,for DFIG rotor voltage referenceθ is a virtual coordinate transformation phase angle.
Compared with the closest prior art, the invention has the following beneficial effects:
according to the DFIG current-limiting and field-suppression control method and the DFIG current-limiting and field-suppression control system, the operation parameters of a power grid and a DFIG power generation system when the voltage of the power grid drops are obtained, the output data of the DFIG power generation system is determined according to the operation parameters of the power grid and the DFIG power generation system when the voltage of the power grid drops, the DFIG rotor voltage compensation quantity, the DFIG rotor voltage field-suppression component, the rotor voltage vector and the voltage decoupling item are determined according to the output data of the DFIG power generation system, the DFIG rotor voltage reference value is determined according to the DFIG rotor voltage compensation quantity, the DFIG rotor voltage field-suppression component, the rotor voltage vector and the voltage decoupling item, and the power switching device. The technical scheme provided by the invention effectively inhibits the rotor impact current at the moment of power grid voltage drop, accelerates the attenuation speed of the transient magnetic linkage of the stator, and further improves the reliability of a control system.
According to the DFIG current-limiting and field-suppression control method and system provided by the invention, the impact current of the rotor at the moment of grid voltage drop is effectively inhibited through the preset virtual resistor, and the attenuation speed of the stator transient magnetic linkage is accelerated by controlling the rotor current vector through the resonator, so that the problems that the traditional control method cannot be quickly and accurately synchronized with the grid voltage vector during low voltage ride through, the control effect is influenced and the stability is caused are solved.
Drawings
FIG. 1 is a flow chart of a DFIG current-limiting and de-excitation control method provided by the invention;
FIG. 2 is a system structure diagram of a DFIG generator set in the DFIG current-limiting and de-excitation control method provided by the invention;
FIG. 3 is a control schematic diagram of a DFIG current-limiting and de-excitation control method provided by the invention;
FIG. 4 is a waveform diagram of a DFIG current-limiting and de-magnetizing control method provided by the present invention;
fig. 5 is a structural diagram of a DFIG current-limiting and de-excitation control system provided by the invention.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 some, but not all, embodiments of the present invention. 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 invention provides a DFIG current-limiting and de-excitation control method, as shown in figure 1, the method comprises the following steps:
acquiring operation parameters of a power grid and a DFIG power generation system when the voltage of the power grid drops;
determining output data of the DFIG power generation system according to the operation parameters of the grid and the DFIG power generation system when the grid voltage drops;
determining a DFIG rotor voltage compensation quantity, a DFIG rotor voltage de-excitation component, a rotor voltage vector and a voltage decoupling term according to output data of the DFIG power generation system;
determining a DFIG rotor voltage reference value according to the DFIG rotor voltage compensation quantity, the DFIG rotor voltage de-excitation component, the rotor voltage vector and the voltage decoupling term;
and controlling the power switch device in the DFIG rotor converter based on the DFIG rotor voltage reference value.
In the embodiment of the invention, the system structure of the DFIG generator set is shown in FIG. 2 and comprises a gear box, a DFIG generator, a machine side converter, a grid side converter, a transformer and a power grid.
In an embodiment of the present invention, the operating parameters include: the system comprises a power grid voltage vector, a stator current vector and a rotor current vector, a stator voltage d-axis component, a stator voltage q-axis component, a stator three-phase current d-axis component, a stator three-phase current q-axis component, an active component of power grid current, a current limiting value of a converter, a stator voltage amplitude, a stator voltage rated value, a power grid line equivalent reactance, a power grid line equivalent resistance and a reactive current reference value of a power grid;
the output data comprises: the active power output by the DFIG stator side, the reactive power reference value required to be sent out by the DFIG unit, the active power reference value required to be sent out by the DFIG unit, the stator flux linkage and the rotor rotation speed angular frequency.
In the embodiment of the invention, as shown in fig. 3, three voltage hall sensors 3 are used for collecting three-phase voltage u on the power grid side in a system consisting of the power grid and the DFIG power generation system 1gabcAnd DFIG stator side three-phase grid phase voltage usabc(ii) a Stator three-phase current i is acquired by using three-phase current Hall sensor 4sabcAnd rotor three-phase current irabcThe collected voltage and current signals pass through a coordinate transformation module 5 to obtain a power grid voltage vector U under a virtual dq coordinate systemgdqStator voltage vector UsdqStator current vector IsdqAnd rotor current vector Irdq；
The obtained stator voltage vector UsdqAnd stator current vector IsdqThe active power P output by the stator side of the DFIG is obtained through the power calculation module 6sAnd reactive power Qs；
According to the obtained power grid voltage vector UgdqAnd stator voltage vector UsdqDetermining a grid voltage amplitude VgAnd a stator voltage amplitude value Vs, and further obtaining a reactive power reference value required to be sent by the DFIG unit through a power reference instruction value calculation module 7And active power reference value
The obtained stator voltage vector UsdqThe stator flux linkage psi is obtained through calculation of a stator flux linkage calculation module 8sdqMeanwhile, a coordinate conversion phase angle theta is obtained by detecting a rotor position detection light code disc 9, and a rotor rotation speed angular frequency omega is obtained by differentiating through a rotation speed differentiator 10r；
The obtained active power P output by the DFIG stator sidesAnd reactive power QsReactive power reference value required to be sent out by DFIG unitAnd active power reference valueStator flux linkage psisdqAnd rotor speed angular frequency omegarCalculating 11 to obtain a rotor voltage reference value through a rotor instruction reference voltage;
the obtained rotor voltage reference value is converted into a two-phase static coordinate system through a virtual dq rotation coordinate system by a conversion module 12 to obtain a DFIG rotor voltage reference value under the two-phase static alpha beta coordinate systemThen the DFIG rotor voltage reference value is comparedAs a reference value of the SVPWM signal generation module 13, a switching signal S of the DFIG side converter is obtained by modulationa、Sb、ScThe obtained switching signal Sa、Sb、ScThe switching devices in the voltage source converter 2 connected to the DFIG rotor windings are controlled.
In the embodiment of the invention, the collected voltage and current signals are subjected to coordinate transformation to obtain a power grid voltage vector U under a virtual dq coordinate systemgdqStator voltage vector UsdqStator current vector IsdqAnd rotor current vector IrdqThe algorithm expression is as follows:
in the above formula, ugdFor d-axis component of the grid voltage, ugqFor the q-axis component of the mains voltage, ugaIs a phase component of the grid voltage a, ugbIs the b-phase component, u, of the grid voltagegcIs the c-phase component, u, of the grid voltagesdIs the d-axis component of the stator voltage, usqIs a stator voltage q-axis component, usaIs a phase component of the stator voltage a, usbIs a stator voltage b-phase component, uscIs a phase component, i, of the stator voltage csdIs d-axis component, i, of stator three-phase currentsqIs a stator three-phase current q-axis component, isaIs a phase component, i, of a stator three-phase currentsbIs a phase component of a stator three-phase current b, iscIs a phase component, i, of a stator three-phase currentrdIs d-axis component, i, of three-phase current of rotorrqFor the q-axis component of the three-phase current of the rotor, iraIs a phase component, i, of a three-phase current of the rotorrbIs the b-phase component, i, of the three-phase current of the rotorrcFor the phase c component of the three-phase current of the rotor, where the virtual coordinate transformation phase angle θ is ω1·t，ω1＝100πrad/s，ω1For a fixed rotation angle frequency, t represents time.
Specifically, the active power P output by the stator side of the DFIGsIs calculated as follows:
the active power Q output by the DFIG stator sidesIs calculated as follows:
in the above formula, usdIs the d-axis component of the stator voltage, usqIs a stator voltage q-axis component, isdIs d-axis component, i, of stator three-phase currentsqIs the q-axis component of the three-phase current of the stator.
In the embodiment of the invention, whenAnd the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
when in useWhen, ifThe reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
otherwise, the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
in the above formula, IpBeing the active component of the grid current, IqBeing a reactive component of the grid current, IsNFor current limiting value, V, of the convertersNFor stator voltage rating, XgFor equivalent reactance of the grid line, ZgAs the line impedance of the grid, RgFor line equivalent resistance, V, of the networksIs the stator voltage amplitude, PsFor active power, V, output from the stator side of the DFIGgFor the amplitude of the voltage of the power network,is the reactive current reference value of the power grid;
wherein the stator voltage amplitude VsIs calculated as follows:
the voltage amplitude V of the power gridgIs calculated as follows:
in the above formula, usdIs the d-axis component of the stator voltage, usqIs a stator voltage q-axis component, ugdFor d-axis component of the grid voltage, ugqIs the q-axis component of the grid voltage.
In particular, the stator flux linkage psisdqIs calculated as follows:
in the above formula, UsdqAnd (t) is a stator voltage vector at the time t.
In particular, the rotor speed angular frequency ωrIs calculated as follows:
in the above equation, θ is a coordinate transformation phase angle.
In an embodiment of the present invention, the determining a DFIG rotor voltage compensation amount, a DFIG rotor voltage demagnetization component, a rotor voltage vector and a voltage decoupling term according to output data of a DFIG power generation system includes:
determining a rotor voltage vector according to active power and reactive power output by the stator side of the DFIG and an active power reference value and a reactive power reference value required to be sent by the DFIG unit;
determining a rotor voltage compensation quantity according to the rotor current vector;
determining a voltage decoupling term according to the stator flux linkage;
and determining a rotor voltage de-excitation component according to the rotor current vector and the stator current vector.
In particular, the rotor voltage vectorIs calculated as follows:
in the above formula, KpFor a given proportionality coefficient, KiFor a given integration coefficient, j is the unit of an imaginary number,the active power reference value required to be sent out by the DFIG unit,reference value of reactive power, P, required to be emitted by DFIG unitsFor active power, Q, output from the stator side of the DFIGsThe active power output by the stator side of the DFIG.
Specifically, the rotor voltage compensation amountIs calculated as follows:
in the above formula, RvVirtual resistance, I, preset for DFIG power generation systemsrdqIs the rotor current vector.
In particular, the voltage decoupling term ErdqIs calculated as follows:
in the above formula, RrIs rotor resistance, LmFor stator-rotor mutual inductance,. psisdqIs stator flux linkage, j is an imaginary unit, ωs＝ω1-ωr，ωsIs the angular frequency of rotation difference, omegarIs the angular frequency, omega, of the rotor speed1＝100πrad/s，ω1To fix the angular frequency of rotation, LrFor equivalent self-inductance of the rotor winding, LmIs the stator-rotor mutual inductance of the DFIG.
Further, the determining the rotor voltage de-excitation component according to the rotor current vector includes:
calculating a DFIG rotor current reference vector according to the DFIG stator current vector;
and substituting the difference value of the DFIG rotor current reference vector and the DFIG rotor current vector into the resonance controller to obtain a DFIG rotor voltage demagnetization component.
Wherein the DFIG rotor current reference vectorIs calculated as follows:
in the above formula, k coefficient of demagnetization, IsdqIs a DFIG stator current vector;
transfer function G of the resonance controllerR(s) the expression is as follows:
in the above formula, K is the demagnetization factor, KprAnd KirAll being the resonance coefficient, omega, of the resonant controllercIs the bandwidth factor, omega, of the resonant controller1＝100πrad/s，ω1For fixed rotation angular frequency, s is the laplacian operator.
In the embodiment of the invention, the DFIG rotor voltage reference valueIs calculated as follows:
in the above formula, ErdqFor voltage decoupling terms, UsdqIs a stator voltage vector, VSIn order to be the stator voltage amplitude,to be the rotor voltage vector,the rotor voltage field suppression component.
In an embodiment of the present invention, the controlling the power switching device in the DFIG rotor converter based on the DFIG rotor voltage reference value includes:
conversion of phase angle theta to DFIG rotor voltage reference value by virtual coordinatePerforming coordinate transformation to obtain the DFIG rotor voltage reference value under the alpha-beta coordinate system
Will be described inThe SVPWM module is used as the input of the SVPWM module to obtain a switching tube driving signal of the rotor converter output by the SVPWM module;
and controlling a power switch device in the DFIG rotor converter by using the switch tube driving signal.
Wherein, the DFIG rotor voltage reference value under the alpha and beta coordinate systemIs calculated as follows:
in the above formula, the first and second carbon atoms are,for DFIG rotor voltage referenceThe d-axis component of (a) is,for DFIG rotor voltage referenceθ is a virtual coordinate transformation phase angle.
In the embodiment of the present invention, as shown in fig. 4, when the grid voltage drops to 0.6p.u. at 1S, part a in the graph is the actual output value S of the apparent power on the stator side simulated by the existing control methodsWaveform of (1), rotor current IrWaveform of (1), stator current IsWaveform and grid voltage UgWherein the stator-side apparent power actual output value Ss＝Ps-jQsJ is an imaginary unit; part B in the figure is the actual output value S of the apparent power at the stator side obtained by the simulation of the control method provided by the inventionsWaveform of (1), rotor current IrWaveform of (1), stator current IsWaveform and grid voltage UgIt is known that the rotor inrush current is suppressed from 3.2p.u. to 1.7p.u., and the transient component of the stator flux linkage is attenuated at a significantly higher speed as seen from the power waveform. Therefore, the invention can effectively restrain the impact current and rapidly extinguish the magnetism when the low voltage passes through.
Based on the same inventive concept, the invention provides a DFIG current-limiting and de-excitation control system, as shown in fig. 5, the system comprises:
the acquisition module is used for acquiring the operating parameters of a power grid and the DFIG power generation system when the voltage of the power grid drops;
the first determining module is used for determining output data of the DFIG power generation system according to the operation parameters of the grid and the DFIG power generation system when the grid voltage drops;
the second determination module is used for determining a DFIG rotor voltage compensation quantity, a DFIG rotor voltage field suppression component, a rotor voltage vector and a voltage decoupling item according to output data of the DFIG power generation system;
the third determining module is used for determining a DFIG rotor voltage reference value according to the DFIG rotor voltage compensation quantity, the DFIG rotor voltage field suppression component, the rotor voltage vector and the voltage decoupling item;
and the control module is used for controlling the power switching device in the DFIG rotor converter based on the DFIG rotor voltage reference value.
In an embodiment of the present invention, the operating parameters include: the system comprises a power grid voltage vector, a stator current vector and a rotor current vector, a stator voltage d-axis component, a stator voltage q-axis component, a stator three-phase current d-axis component, a stator three-phase current q-axis component, an active component of power grid current, a current limiting value of a converter, a stator voltage amplitude, a stator voltage rated value, a power grid line equivalent reactance, a power grid line equivalent resistance and a reactive current reference value of a power grid.
The output data comprises: the active power output by the DFIG stator side, the reactive power reference value required to be sent out by the DFIG unit, the active power reference value required to be sent out by the DFIG unit, the stator flux linkage and the rotor rotation speed angular frequency.
Specifically, the active power P output by the stator side of the DFIGsIs calculated as follows:
the active power Q output by the DFIG stator sidesIs calculated as follows:
in the above formula, usdIs the d-axis component of the stator voltage, usqIs a stator voltage q-axis component, isdIs d-axis component, i, of stator three-phase currentsqIs the q-axis component of the three-phase current of the stator.
In the embodiment of the invention, whenAnd the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
when in useWhen, ifThe reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the above-mentionedActive power reference value required to be sent out by DFIG unitIs calculated as follows:
otherwise, the reference value of the reactive power required to be sent out by the DFIG unitIs calculated as follows:
the active power reference value required to be sent by the DFIG unitIs calculated as follows:
in the above formula, IpBeing the active component of the grid current, IqBeing a reactive component of the grid current, IsNFor current limiting value, V, of the convertersNFor stator voltage rating, XgFor equivalent reactance of the grid line, ZgAs the line impedance of the grid, RgFor line equivalent resistance, V, of the networksIs the stator voltage amplitude, PsFor active power, V, output from the stator side of the DFIGgFor the amplitude of the voltage of the power network,is the reactive current reference value of the power grid.
Wherein the stator flux linkage psisdqIs calculated as follows:
in the above formula, UsdqAnd (t) is a stator voltage vector at the time t.
The rotor speed angular frequency ωrIs calculated as follows:
in the above equation, θ is a coordinate transformation phase angle.
Specifically, the second determining module includes:
the first determining unit is used for determining a rotor voltage vector according to active power and reactive power output by the DFIG stator side and an active power reference value and a reactive power reference value required to be sent by the DFIG unit;
the second determining unit is used for determining a rotor voltage compensation quantity according to the rotor current vector;
the third determining unit is used for determining a voltage decoupling term according to the stator flux linkage;
and the fourth determining unit is used for determining the rotor voltage de-excitation component according to the rotor current vector and the stator current vector.
Wherein the rotor voltage vectorIs calculated as follows:
in the above formula, KpFor a given proportionality coefficient, KiFor a given integration coefficient, j is the unit of an imaginary number,the active power reference value required to be sent out by the DFIG unit,reference value of reactive power, P, required to be emitted by DFIG unitsFor active power, Q, output from the stator side of the DFIGsThe active power output by the stator side of the DFIG.
The rotor voltage compensation amountIs calculated as follows:
in the above formula, RvVirtual resistance, I, preset for DFIG power generation systemsrdqIs the rotor current vector.
The voltage decoupling term ErdqIs calculated as follows:
in the above formula, RrIs rotor resistance, LmFor stator-rotor mutual inductance,. psisdqIs stator flux linkage, j is an imaginary unit, ωs＝ω1-ωr，ωsIs the angular frequency of rotation difference, omegarIs the angular frequency, omega, of the rotor speed1＝100πrad/s，ω1To fix the angular frequency of rotation, LrFor equivalent self-inductance of the rotor winding, LmIs the stator-rotor mutual inductance of the DFIG.
Specifically, the determining the rotor voltage demagnetization component according to the rotor current vector includes:
calculating a DFIG rotor current reference vector according to the DFIG stator current vector;
and substituting the difference value of the DFIG rotor current reference vector and the DFIG rotor current vector into the resonance controller to obtain a DFIG rotor voltage demagnetization component.
Wherein the DFIG rotor current reference vectorIs calculated as follows:
in the above formula, k coefficient of demagnetization, IsdqIs the DFIG stator current vector.
In the embodiment of the invention, the DFIG rotor voltage reference valueIs calculated as follows:
in the above formula, ErdqFor voltage decoupling terms, UsdqIs a stator voltage vector, VSIn order to be the stator voltage amplitude,to be the rotor voltage vector,the rotor voltage field suppression component.
In an embodiment of the present invention, the control module includes:
an acquisition unit for converting the phase angle theta to DFIG rotor voltage reference value by virtual coordinatePerforming coordinate transformation to obtain the DFIG rotor voltage reference value under the alpha-beta coordinate system
An output unit for outputting the aboveThe SVPWM module is used as the input of the SVPWM module to obtain a switching tube driving signal of the rotor converter output by the SVPWM module;
and the control unit is used for controlling a power switch device in the DFIG rotor converter by utilizing the switch tube driving signal.
Wherein, the DFIG rotor voltage reference value under the alpha and beta coordinate systemIs calculated as follows:
in the above formula, the first and second carbon atoms are,for DFIG rotor voltage referenceThe d-axis component of (a) is,for DFIG rotor voltage referenceθ is a virtual coordinate transformation phase angle.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
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