CN113935152A

CN113935152A - Permanent magnet wind driven generator, design method and system thereof, electronic equipment and medium

Info

Publication number: CN113935152A
Application number: CN202111121206.6A
Authority: CN
Inventors: 吴立建; 杜一东; 王文婷; 闻汇; 施杨; 詹皓岚; 缪骏
Original assignee: Zhejiang University ZJU; Shanghai Electric Wind Power Group Co Ltd
Current assignee: Zhejiang University ZJU; Shanghai Electric Wind Power Group Co Ltd
Priority date: 2021-09-24
Filing date: 2021-09-24
Publication date: 2022-01-14

Abstract

The invention discloses a permanent magnet wind driven generator and a design method, a system, electronic equipment and a medium thereof, wherein the method comprises the following steps: determining a feasible working temperature range and a preset working temperature point of the permanent magnet based on set conditions; the method comprises the steps of obtaining actual rated grid-connected power of a permanent magnet at each preset working temperature point after each demagnetization influence event occurs, obtaining a first power generation related parameter of a generator at the preset working temperature point and a second power generation related parameter at a second reference working temperature, and finally obtaining target parameters to update or redesign the permanent magnet wind driven generator. The invention allows the permanent magnet demagnetization to occur, does not need to reduce the design boundary, and quantitatively evaluates the influence and the cumulative effect of the permanent magnet on the electromagnetic performance of the permanent magnet wind driven generator due to multiple irreversible demagnetization.

Description

Permanent magnet wind driven generator, design method and system thereof, electronic equipment and medium

Technical Field

The invention relates to the technical field of generator design, in particular to a permanent magnet wind driven generator and a design method, a system, electronic equipment and a medium thereof.

Background

In the current wind power generator design, a permanent magnet is generally adopted as an excitation source, and high power density and high torque density can be realized. However, the use of permanent magnets may result in irreversible demagnetization failure of some or all of the rotor permanent magnets. The irreversible demagnetization of the motor means that the working point of a permanent magnet moves below the inflection point of a demagnetization curve under the action of stator current locally or wholly, when the stator current is removed or the stator current is small, the permanent magnet cannot recover according to the original demagnetization curve, a new recovery line is generated below the inflection point, the residual magnetic induction intensity on the curve is obviously lower than that of the original curve, and further the back electromotive force of the motor is reduced, and the loss of the performance such as electromagnetic torque is caused.

In the whole life cycle of the practical use of the wind driven generator, due to the fact that the operation period is generally long, a plurality of problems such as short-circuit faults, open-phase operation, environmental temperature influence and the like can occur for many times in the operation process, and particularly, the short-circuit faults can generate huge reverse magnetic fields to cause irreversible demagnetization of permanent magnets. Which will directly affect the operational performance, the power generation capacity, etc. of the wind turbine. Therefore, in the traditional design process, designers can evaluate the demagnetization condition of the wind driven generator so as to avoid the irreversible demagnetization of the permanent magnet.

At present, in order to completely avoid irreversible demagnetization of a permanent magnet under any condition, designers often sacrifice part of economic performance to achieve the goal by reducing design boundaries, such as reducing the working temperature of the permanent magnet. The design scheme obtained according to the method can theoretically ensure that the loss of the generated energy caused by demagnetization can not be generated in the full life cycle of the wind driven generator. However, the traditional design method of the permanent magnet wind driven generator does not allow the permanent magnet to be demagnetized, and the improvement of the economic benefit of the whole life cycle is further restricted by reducing the design boundary and sacrificing the electromagnetic performance.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a permanent magnet wind driven generator, a design method and system thereof, electronic equipment and a medium.

The invention solves the technical problems through the following technical scheme:

the invention provides a design method of a permanent magnet wind driven generator, which comprises the following steps:

determining a feasible working temperature range of the permanent magnet based on a design target, a first constraint condition and a second constraint condition, and selecting a plurality of preset working temperature points in the feasible working temperature range;

the first constraint condition is used for limiting the insulation grade of a generator winding, and the second constraint condition is used for limiting the design size of the permanent magnet wind driven generator;

presetting a plurality of demagnetization influencing events, the occurrence frequency of each demagnetization influencing event in a set full life cycle and the occurrence time corresponding to each occurrence;

for each demagnetization influencing event in the set full life cycle, respectively acquiring the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after the demagnetization influencing event occurs at each occurrence time, and acquiring a first power generation related parameter of the permanent magnet wind driven generator at each preset working temperature point;

acquiring a second power generation associated parameter corresponding to the permanent magnet wind driven generator at a first reference working temperature;

the first power generation related parameter and the second power generation related parameter are both information related to the power generation amount of the permanent magnet wind power generator;

and comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result, and determining a target design parameter corresponding to the permanent magnet wind driven generator based on the comparison result.

Preferably, the step of comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result, and determining a target design parameter corresponding to the permanent magnet wind turbine based on the comparison result includes:

comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result;

judging whether the comparison result is larger than an upper limit value of a preset range, if so, selecting a preset temperature working point corresponding to a first power generation related parameter which is ranked earlier to update to obtain a new first reference working temperature to serve as a target reference working temperature of the permanent magnet, adopting the target reference working temperature to redesign the target design parameter corresponding to the permanent magnet wind power generator, and re-executing the step of determining a feasible working temperature range of the permanent magnet based on a design target, a first constraint condition and a second constraint condition, and selecting a plurality of preset working temperature points in the feasible working temperature range;

if not, judging whether the comparison result falls into the preset range or not, if so, selecting a preset temperature working point corresponding to a first power generation related parameter in the front sequence to update a first reference working temperature and/or a first reference current parameter corresponding to the permanent magnet wind driven generator, and taking an initial design parameter corresponding to the selected preset temperature working point as the target design parameter corresponding to the permanent magnet wind driven generator; and if the comparison result is smaller than the lower limit value of the preset range, taking the first reference working temperature corresponding to the second power generation related parameter as the target reference working temperature of the permanent magnet, and taking the initial design parameter corresponding to the target reference working temperature as the target design parameter corresponding to the permanent magnet wind driven generator.

Preferably, after the step of selecting a plurality of preset operating temperature points within the feasible operating temperature range, the step of respectively obtaining the actual rated grid-connected power of the permanent magnet corresponding to each preset operating temperature point after the demagnetization influencing event occurs at each occurrence time further includes:

adjusting the set loss based on the heat dissipation model, and acquiring a corresponding loss value when the working temperature of the permanent magnet is adjusted to the preset working temperature point;

the set loss comprises at least one of stator iron loss, rotor loss, fingerboard loss, harmonic loss, bearing loss, cable loss, converter loss and auxiliary loss;

calculating to obtain the winding temperature corresponding to the generator winding based on the loss value;

calculating a winding resistance value based on the winding temperature;

calculating to obtain the input current of the generator according to the loss value and the winding resistance value;

adjusting a current phase in the input current magnitude to meet a target voltage level under the design objective;

acquiring a first rated grid-connected power corresponding to the permanent magnet at each preset working temperature point under the adjusted input current;

and screening out a preset working temperature point at which the first rated grid-connected power is greater than or equal to the target rated grid-connected power in the design target and is less than the maximum rated grid-connected power.

Preferably, the step of respectively obtaining the actual rated grid-connected power of the permanent magnet at each preset working temperature point after the demagnetization influencing event occurs at each occurrence time includes:

respectively acquiring a demagnetization curve corresponding to the permanent magnet at each preset working temperature point after the demagnetization influencing event occurs at each occurrence time;

adjusting the current phase of the rated current of the wind driven generator based on the demagnetization curve to meet the target voltage level under the design target; the rated current is the current magnitude under the first rated grid-connected power corresponding to each preset working temperature point of the wind driven generator;

and calculating to obtain the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after demagnetization based on the regulated rated current and the demagnetization curve after demagnetization of the permanent magnet.

Preferably, the step of obtaining a first power generation related parameter of the permanent magnet wind turbine at each preset operating temperature point includes:

calculating to obtain a net present value NPV of the permanent magnet wind power generator at each preset working temperature point based on the duration of different wind speeds in a set time period, the electricity consumption unit price and the manufacturing cost of the generator;

wherein the magnitude of the net present value NPV is positively correlated with the magnitude of the generated energy of the generator.

Preferably, the step of calculating the net present value NPV of the permanent magnet wind turbine at each preset operating temperature point further includes:

calculating to obtain the grid-connected power of the generator at different wind speeds based on different wind speeds and corresponding rotor loss at the wind speeds;

under the condition of rated wind speed, after each demagnetization influence event occurs, adjusting the phase of the rated current, keeping the current magnitude unchanged until the target voltage level under the design target is met, and calculating to obtain the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after demagnetization;

under the condition of non-rated wind speed, after each demagnetization influence event occurs, calculating by adopting the current magnitude and the phase corresponding to the generator when no demagnetization influence event occurs to obtain grid-connected power after the demagnetization influence event occurs; or compensating the generated energy of the generator by adopting a current compensation mode until the generated energy corresponding to the generator is generated when any demagnetization influence event does not occur.

establishing a net present value NPV matrix according to the net present value NPV;

each parameter in the net present value NPV matrix corresponds to the net present value NPV under two dimensions of different preset working temperature points and different demagnetization conditions respectively;

calculating all net present values NPV at the same preset working temperature to obtain first processed values NPV so as to obtain first processed values NPV corresponding to each preset working temperature;

acquiring a second processing value NPV corresponding to the first reference working temperature;

calculating to obtain the ratio of different first processing values NPV to the second processing values NPV;

judging whether the ratio is larger than a first set threshold value or not, selecting a corresponding preset working temperature point to update to obtain a new first reference working temperature serving as a target reference working temperature of the permanent magnet, adopting the target reference working temperature to redesign to obtain a target design parameter corresponding to the permanent magnet wind power generator, executing the step of determining a feasible working temperature range of the permanent magnet based on a design target, a first constraint condition and a second constraint condition again, and selecting a plurality of preset working temperature points in the feasible working temperature range;

otherwise, judging whether the ratio is smaller than or equal to the first set threshold and larger than or equal to a second set threshold, if so, selecting a preset working temperature point corresponding to the highest ratio as a target reference working temperature of the permanent magnet, adopting the target reference working temperature as the first reference working temperature and/or the first reference current parameter corresponding to the permanent magnet wind power generator, and taking an initial design parameter corresponding to the first reference working temperature as the target design parameter corresponding to the permanent magnet wind power generator;

and if all the ratios are smaller than the second set threshold, taking the first reference working temperature as the target reference working temperature of the permanent magnet, and taking the initial design parameters corresponding to the target reference working temperature as the target design parameters corresponding to the permanent magnet wind driven generator.

Preferably, the design target comprises a target rated grid-connected power, a target rated rotating speed and a target voltage level;

the step of determining a feasible operating temperature range of the permanent magnet based on the design objective, the first constraint and the second constraint comprises:

determining a dimensional reference parameter for the permanent magnet wind turbine based on the design objective and the second constraint;

the second constraint condition comprises limit conditions of processing assembly and transportation, the size reference parameter comprises an envelope size parameter and an internal size parameter of the generator, the envelope size parameter comprises an outer diameter and/or an axial length, and the internal size parameter comprises at least one of the outer diameter, the axial length, an air gap length, a permanent magnet thickness, a permanent magnet width, a stator core size and a rotor core size;

performing single-target or multi-target optimization on the size reference parameter according to the design target to obtain the optimized size reference parameter;

adjusting and acquiring an input current parameter reaching the design target based on the optimized size reference parameter, and calculating to obtain a loss parameter associated with the generator based on the input current parameter;

iteratively adjusting the input current parameter based on the loss parameter and the heat dissipation model until a working temperature which correspondingly reaches a design target under the initial design of the permanent magnet and a feasible working temperature range under a first constraint condition are obtained.

Preferably, the plurality of preset working temperature points comprise the first reference working temperature and are arranged in an equal difference mode; and/or the presence of a gas in the gas,

the demagnetization influencing event comprises one-phase short circuit, two-phase short circuit, three-phase short circuit, heavy current overload, high-temperature overload, overheating or turn-to-turn short circuit.

The invention also provides a design system of the permanent magnet wind driven generator, which comprises the following components:

the temperature range acquisition module is used for determining the feasible working temperature range of the permanent magnet based on the design target, the first constraint condition and the second constraint condition;

the temperature point selection module is used for selecting a plurality of preset working temperature points within the feasible working temperature range;

wherein the first constraint is used for limiting the insulation level of the generator winding, and the second constraint is used for limiting the design size of the generator;

the parameter presetting module is used for presetting a plurality of demagnetization influencing events, the occurrence frequency of each demagnetization influencing event in a set full life cycle and the occurrence time corresponding to each occurrence;

the actual power acquisition module is used for respectively acquiring the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after each demagnetization influence event occurs at each occurrence time for each demagnetization influence event in the set full life cycle;

the first correlation parameter acquisition module is used for acquiring first power generation correlation parameters of the permanent magnet wind driven generator at each preset working temperature point;

the second associated parameter acquisition module is used for acquiring a second power generation associated parameter corresponding to the permanent magnet at the first reference working temperature;

wherein the first and second power generation related parameters are associated with the amount of power generated by the permanent magnet wind generator;

the comparison module is used for comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result;

and the target parameter acquisition module is used for determining target design parameters corresponding to the permanent magnet wind driven generator based on the comparison result.

Preferably, the comparison module is configured to compare the first power generation related parameter with the second power generation related parameter to obtain a comparison result; judging whether the comparison result is larger than an upper limit value of a preset range, if so, calling the target parameter acquisition module to select a preset temperature working point corresponding to a first power generation related parameter which is ranked earlier to update to obtain a new first reference working temperature to serve as a target reference working temperature of the permanent magnet, adopting the target reference working temperature to redesign a target design parameter corresponding to the permanent magnet wind driven generator, and calling the temperature range acquisition module; if not, judging whether the comparison result falls into the preset range, if so, calling the target parameter acquisition module to select a preset temperature working point corresponding to a first power generation associated parameter in the front sequence to update a first reference working temperature and/or a first reference current parameter corresponding to the permanent magnet wind driven generator, and taking an initial design parameter corresponding to the selected preset temperature working point as the target design parameter corresponding to the permanent magnet wind driven generator; and if the comparison result is smaller than the lower limit value of the preset range, calling the target parameter acquisition module to use the first reference working temperature corresponding to the second power generation related parameter as the target reference working temperature of the permanent magnet, and using the initial design parameter corresponding to the target reference working temperature as the target design parameter corresponding to the permanent magnet wind driven generator.

Preferably, the design system further comprises:

the loss value acquisition module is used for adjusting the set loss based on the heat dissipation model and acquiring a corresponding loss value when the working temperature of the permanent magnet is adjusted to the preset working temperature point;

the winding temperature calculation module is used for calculating the winding temperature corresponding to the generator winding based on the loss value;

the winding resistance value calculation module is used for calculating a winding resistance value based on the winding temperature;

the input current calculation module is used for calculating the input current of the generator according to the loss value and the winding resistance value;

the current parameter adjusting module is used for adjusting the current phase in the input current magnitude to meet the target voltage level under the design target;

the first rated power acquisition module is used for acquiring corresponding first rated grid-connected power of the permanent magnet at each preset working temperature point under the adjusted input current;

and the target rated grid-connected power screening module is used for screening out the first rated grid-connected power which is greater than or equal to the target rated grid-connected power in the design target and screening out a preset working temperature point which is less than the maximum rated grid-connected power.

Preferably, the actual power obtaining module includes:

a demagnetization curve acquisition unit, configured to acquire a demagnetization curve corresponding to the permanent magnet at each preset working temperature point after the demagnetization influencing event occurs at each occurrence time;

the current adjusting unit is used for adjusting the current phase of the rated current of the wind driven generator based on the demagnetization curve so as to meet the target voltage level under the design target; the rated current is the current magnitude under the first rated grid-connected power corresponding to each preset working temperature point of the wind driven generator;

and the actual power acquisition unit is used for calculating to obtain the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after demagnetization based on the regulated rated current and the demagnetization curve of the permanent magnet after demagnetization.

Preferably, the first correlation parameter obtaining module is configured to calculate, based on duration of different wind speeds in a set time period, unit price of power consumption, and manufacturing cost of the generator, a net present value NPV of the permanent magnet wind turbine at each preset operating temperature point;

Preferably, the design system further comprises:

the power calculation module is used for calculating and obtaining grid-connected power of the generator at different wind speeds based on different wind speeds and corresponding rotor loss at the wind speeds;

the power calculation module is used for adjusting the phase of current and keeping the current unchanged until the target voltage grade under the design target is met after each demagnetization influence event occurs under the condition of rated wind speed, and calculating the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after demagnetization;

the power calculation module is used for calculating the grid-connected power after the demagnetization influence event occurs by adopting the current magnitude and the phase corresponding to the generator when no demagnetization influence event occurs under the condition of non-rated wind speed; or compensating the generated energy of the generator by adopting a current compensation mode until the generated energy corresponding to the generator is generated when any demagnetization influence event does not occur.

Preferably, the design system should include:

the matrix establishing module is used for establishing a net present value NPV matrix according to the net present value NPV;

the first associated parameter acquisition module is used for calculating all net present values NPV at the same preset working temperature to obtain first processed values NPV so as to acquire a first processed value NPV corresponding to each preset working temperature;

the second associated parameter acquisition module is used for acquiring a corresponding second processing value NPV at the first reference working temperature;

the comparison module is used for calculating to obtain the ratio of different first processing values NPV to different second processing values NPV, judging whether the ratio is larger than a first set threshold value, selecting a corresponding preset working temperature point to update to obtain a new first reference working temperature to serve as a target reference working temperature of the permanent magnet, adopting the target reference working temperature to redesign to obtain a target design parameter corresponding to the permanent magnet wind driven generator, and calling the temperature range acquisition module;

if the ratio is smaller than or equal to the first set threshold and larger than or equal to the second set threshold, the target parameter acquisition module is called to select a preset working temperature point corresponding to the highest ratio as a target reference working temperature of the permanent magnet, the target reference working temperature is used as the first reference working temperature and/or the first reference current parameter corresponding to the permanent magnet wind power generator, and an initial design parameter corresponding to the first reference working temperature is used as the target design parameter corresponding to the permanent magnet wind power generator;

and the comparison module is used for taking the first reference working temperature as a target reference working temperature of the permanent magnet and taking an initial design parameter corresponding to the target reference working temperature as the target design parameter corresponding to the permanent magnet wind driven generator if all the ratios are smaller than the second set threshold.

preferably, the temperature range acquiring module includes:

a size parameter determination unit for determining a size reference parameter of the permanent magnet wind turbine based on the design objective and the second constraint condition;

the size parameter optimization unit is used for carrying out single-target or multi-target optimization on the size reference parameter according to the design target so as to obtain the optimized size reference parameter;

the loss parameter acquisition unit is used for adjusting and acquiring an input current parameter reaching the design target based on the optimized size reference parameter, and calculating to obtain a loss parameter associated with the generator based on the input current parameter;

and the initial parameter obtaining unit is used for iteratively adjusting the input current parameter based on the loss parameter and the heat dissipation model until obtaining the working temperature of the permanent magnet, which correspondingly reaches the design target under the initial design, and the feasible working temperature range under the first constraint condition.

The invention also provides a permanent magnet wind driven generator which comprises the design system of the permanent magnet wind driven generator.

The invention also provides an electronic device, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor realizes the design method of the permanent magnet wind driven generator when executing the computer program.

The invention also provides a computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method of designing a permanent magnet wind turbine described above.

On the basis of the common knowledge in the field, the preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.

The positive progress effects of the invention are as follows:

according to the method, the influence and the cumulative effect of multiple irreversible demagnetization of the permanent magnet on the electromagnetic performance of the permanent magnet wind driven generator are quantitatively evaluated, a near-limit design method of the permanent magnet wind driven generator under complex constraint is provided, the local demagnetization of the permanent magnet is reasonably utilized, the working current threshold is improved, the matching design of the demagnetization resistance of the permanent magnet is realized, namely the demagnetization resistance of the permanent magnet is allowed to occur, the design boundary does not need to be reduced, for example, the permanent magnet can work at a higher temperature, the performances of the wind driven generator such as the generated energy can be further improved, the generated energy base number is improved compared with the traditional design method after demagnetization occurs due to faults in the later period, and the generated energy base number and the economic benefit of the permanent magnet wind driven generator can be optimized in the whole life cycle.

Drawings

Fig. 1 is a first flowchart of a design method of a permanent magnet wind turbine according to embodiment 1 of the present invention.

Fig. 2 is a second flowchart of a design method of a permanent magnet wind turbine according to embodiment 1 of the present invention.

Fig. 3 is a flowchart of a design method of a permanent magnet wind turbine according to embodiment 2 of the present invention.

Fig. 4 is a schematic diagram of the demagnetization distribution of the permanent magnet under a three-phase short circuit in embodiment 2 of the present invention.

Fig. 5 is a schematic structural diagram of a permanent magnet direct-drive outer rotor wind turbine generator according to embodiment 2 of the present invention.

Fig. 6 is a schematic diagram of demagnetization curves of a permanent magnet N45H at different temperatures in example 2 of the present invention.

Fig. 7 is a schematic diagram showing the relationship between the dc copper loss and the temperature of the permanent magnet in embodiment 2 of the present invention.

Fig. 8 is a schematic diagram showing a relationship between the winding temperature and the permanent magnet temperature in embodiment 2 of the present invention.

Fig. 9 is a schematic diagram of a relationship between the winding resistance and the temperature of the permanent magnet in embodiment 2 of the present invention.

Fig. 10 is a schematic diagram showing a relationship between a rated current and a temperature of a permanent magnet in embodiment 2 of the present invention.

Fig. 11 is a schematic diagram of a relationship between a rated current phase and a temperature of a permanent magnet in embodiment 2 of the present invention.

Fig. 12 is a schematic diagram showing a relationship between output power and temperature of the permanent magnet in embodiment 2 of the present invention.

Fig. 13 is a schematic diagram of demagnetization curves after various demagnetization affecting events in embodiment 2 of the present invention.

Fig. 14 is a schematic diagram of a variation relationship of the rated grid-connected power at different permanent magnet operating temperatures when a demagnetization influencing event occurs in embodiment 2 of the present invention.

Fig. 15 is a schematic diagram of the duration of the wind power discharge machine in one year at various wind speeds in embodiment 2 of the present invention.

Fig. 16 is a schematic diagram of a relationship between an input power curve and an input power in embodiment 2 of the present invention.

Fig. 17 is a schematic diagram of a relationship between an NPV and a permanent magnet operating temperature when a demagnetization influencing event occurs in embodiment 2 of the present invention.

FIG. 18 is a schematic diagram showing a direct proportional function relationship between the correction coefficients μ and n'/n in example 2 of the present invention.

FIG. 19 is a schematic diagram of the step function relationship between the correction coefficients μ and n'/n in example 2 of the present invention.

FIG. 20 is a schematic diagram showing the relationship between NPV' and the temperature of a permanent magnet in embodiment 2 of the present invention.

FIG. 21 shows NPV'/NPV in example 2 of the present invention_Y' temperature dependence of permanent magnets.

Fig. 22 is a block diagram schematically illustrating a design system of a permanent magnet wind turbine according to embodiment 3 of the present invention.

Fig. 23 is a schematic structural diagram of an electronic device for implementing a method for designing a permanent magnet wind turbine according to embodiment 5 of the present invention.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

Example 1

As shown in fig. 1, the design method of the permanent magnet wind turbine of the present embodiment includes:

s101, determining a feasible working temperature range of the permanent magnet based on a design target, a first constraint condition and a second constraint condition, and selecting a plurality of preset working temperature points in the feasible working temperature range;

wherein the first constraint is for limiting the generator winding insulation level.

The second constraint is used to limit the design size of the permanent magnet wind turbine.

Specifically, the second constraint condition includes, but is not limited to, the limitation of machining assembly and transportation, the size reference parameter includes an envelope size parameter of the generator and an internal size parameter, the envelope size parameter includes an outer diameter and/or an axial length, and the internal size parameter includes an outer diameter, an axial length, an air gap length, a permanent magnet thickness, a permanent magnet width, a stator core size, a rotor core size and the like.

Design goals include, but are not limited to, a target grid-connected power rating, a target rotational speed rating, and a target voltage rating.

S102, presetting a plurality of demagnetization influencing events, and the occurrence frequency and the occurrence time of each demagnetization influencing event in a set full life cycle;

wherein, the demagnetization influencing event includes but is not limited to one-phase short circuit, two-phase short circuit, three-phase short circuit, heavy current overload, high temperature overload, overheating or turn-to-turn short circuit.

S103, respectively acquiring the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after each occurrence time of each demagnetization influence event in the set full life cycle, and acquiring a first power generation related parameter of the permanent magnet wind driven generator at each preset working temperature point;

s104, acquiring a second power generation related parameter corresponding to the permanent magnet wind driven generator at the first reference working temperature;

the first reference working temperature can be the same as or different from one of a plurality of preset working temperature points; the method can be determined and adjusted according to actual design requirements.

The first power generation related parameter and the second power generation related parameter are information related to the power generation amount of the permanent magnet wind driven generator;

s105, comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result, and determining a target design parameter corresponding to the permanent magnet wind driven generator based on the comparison result.

Specifically, as shown in fig. 2, step S105 includes:

s10511, comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result;

s10512, judging whether the comparison result is larger than the upper limit value of the preset range, if so, selecting a preset temperature working point corresponding to a first power generation related parameter which is ranked earlier to update to obtain a new first reference working temperature to serve as the target reference working temperature of the permanent magnet, adopting the target reference working temperature to redesign a target design parameter corresponding to the permanent magnet wind power generator, and re-executing a step of determining the feasible working temperature range of the permanent magnet based on the design target, the first constraint condition and the second constraint condition, and selecting a plurality of preset working temperature points in the feasible working temperature range;

if not, judging whether the comparison result falls into a preset range or not, if so, selecting a preset temperature working point corresponding to a first power generation associated parameter in the front sequence to update a first reference working temperature and/or a first reference current parameter corresponding to the permanent magnet wind driven generator, and taking an initial design parameter corresponding to the selected preset temperature working point as a target design parameter corresponding to the permanent magnet wind driven generator; and if the comparison result is smaller than the lower limit value of the preset range, taking the first reference working temperature corresponding to the second power generation related parameter as the target reference working temperature of the permanent magnet, and taking the initial design parameter corresponding to the target reference working temperature as the target design parameter corresponding to the permanent magnet wind driven generator.

And the target reference working temperature is a new first reference working temperature corresponding to the wind driven generator.

In the embodiment, the influence and the cumulative effect of the permanent magnet on the electromagnetic performance of the permanent magnet wind driven generator by multiple irreversible demagnetization are quantitatively evaluated, a near-limit design method of the permanent magnet wind driven generator under complex constraint is provided, by reasonably utilizing the local demagnetization of the permanent magnet, the working current threshold is improved, the matching design of the demagnetization resistance of the permanent magnet is realized, namely, the demagnetization of the permanent magnet is allowed to occur without reducing the design boundary, for example, the permanent magnet can work at higher temperature, and the performances of the wind driven generator such as the power generation capacity and the like can be further improved, so that the generated energy has partial loss after demagnetization caused by faults in the later period, but the generated energy base number is improved compared with the traditional design method, therefore, the generated energy and the economic benefit of the permanent magnet wind driven generator can be optimal in the whole life cycle.

Example 2

The design method of the permanent magnet wind power generator of the embodiment is a further improvement of the embodiment 1, and specifically comprises the following steps:

in an embodiment, as shown in fig. 3, step S101 includes:

s1011, determining size reference parameters of the permanent magnet wind driven generator based on the design target and the second constraint condition;

s1012, performing single-target or multi-target optimization on the size reference parameter according to the design target to obtain the optimized size reference parameter;

where single or multiple targets include efficiency, power factor, cost, etc.

Other algorithms such as a genetic algorithm, a sequential optimization iteration method, a gradient descent algorithm and the like can be adopted to carry out single-target or multi-target optimization.

S1013, adjusting and acquiring input current parameters reaching a design target based on the optimized size reference parameters, and calculating to obtain loss parameters related to the generator based on the input current parameters;

and S1014, iteratively adjusting the input current parameters based on the loss parameters and the heat dissipation model until the working temperature of the permanent magnet correspondingly reaching the design target under the initial design and the feasible working temperature range under the first constraint condition are obtained.

The heat dissipation model includes a finite element model, a CFD (computational fluid dynamics) model, a heat network model, and the like.

In addition, in order to avoid the situation of demagnetization of the permanent magnet, the demagnetization volume ratio of the permanent magnet under each demagnetization influence event can be obtained; and when the demagnetization volume ratio is larger than the first set threshold, adjusting the size reference parameter, and executing the step S1011 again until the demagnetization volume ratio of the permanent magnet under each demagnetization influence event is smaller than the first set threshold, and acquiring the adjusted size reference parameter.

As shown in fig. 4, the schematic diagram of demagnetization distribution on the permanent magnet is shown when the demagnetization influencing event is a three-phase short circuit; wherein a corresponds to a demagnetization region in which demagnetization occurs after a three-line short circuit.

It should be noted that, in the embodiment, the demagnetization checking operation needs to be performed when the design is performed for the first time, and in the subsequent redesign execution step, the demagnetization checking operation does not need to be performed again, and only the temperature checking process needs to be performed.

Step S103 further includes:

adjusting the set loss based on the heat dissipation model, and acquiring a corresponding loss value when the working temperature of the permanent magnet is adjusted to a preset working temperature point;

the set loss comprises at least one of stator iron loss, rotor loss, finger plate loss, harmonic loss, bearing loss, cable loss, converter loss and auxiliary loss;

calculating a winding resistance value based on the winding temperature;

adjusting the current phase in the input current magnitude to meet the target voltage level under the design target;

acquiring corresponding first rated grid-connected power of the permanent magnet at each preset working temperature point under the adjusted input current;

and screening out a preset working temperature point of which the first rated grid-connected power is greater than or equal to the target rated grid-connected power in the design target, and screening out a preset working temperature point of which the first rated grid-connected power is less than the maximum rated grid-connected power.

Step S103 includes:

respectively acquiring a demagnetization curve corresponding to the permanent magnet at each preset working temperature point after a demagnetization influence event occurs at each occurrence time;

adjusting the current phase of the rated current of the wind driven generator based on the demagnetization curve to meet the target voltage level under the design target; the rated current is the current under the first rated grid-connected power corresponding to each preset working temperature point of the wind driven generator.

And calculating to obtain the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after demagnetization based on the regulated rated current and the demagnetization curve of the permanent magnet after demagnetization.

In step S103, the step of obtaining a first power generation related parameter of the permanent magnet wind turbine at each preset operating temperature point includes:

calculating to obtain a net present value NPV of the permanent magnet wind driven generator at each preset working temperature point based on the duration of different wind speeds in a set time period, the electricity consumption unit price and the manufacturing cost of the generator;

wherein, the magnitude of the net present value NPV is positively correlated with the magnitude of the generated energy of the generator.

Specifically, the step of calculating the net present value NPV of the permanent magnet wind turbine at each preset operating temperature point further includes:

calculating to obtain the grid-connected power of the generator at different wind speeds based on different wind speeds and the rotor loss at the corresponding wind speed;

under the condition of rated wind speed, after each demagnetization influence event occurs, adjusting the phase of current and keeping the current unchanged until the target voltage level under the design target is met, and calculating to obtain the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after demagnetization;

In an implementation scenario, step S105 includes:

s10521, establishing a net present value NPV matrix according to the net present value NPV;

s10522, calculating all net present values NPV at the same preset working temperature to obtain a first processed value NPV so as to obtain a first processed value NPV corresponding to each preset working temperature;

and calculating all the net present values NPV in calculation modes such as summation and expectation value calculation to obtain a first processed value NPV.

S10523, acquiring a second processing value NPV corresponding to the first reference working temperature;

s10524, calculating to obtain the ratio of the different first processed value NPV to the second processed value NPV;

s10525, judging whether the ratio is larger than a first set threshold value, selecting a corresponding preset working temperature point to update to obtain a new first reference working temperature as a target reference working temperature of the permanent magnet, adopting the target reference working temperature to redesign to obtain a target design parameter corresponding to the permanent magnet wind driven generator, and executing the step S101 again; otherwise, judging whether the ratio is smaller than or equal to a first set threshold and larger than or equal to a second set threshold, if so, selecting a preset working temperature point corresponding to the highest ratio as a target reference working temperature of the permanent magnet, adopting the target reference working temperature as a first reference working temperature and/or a first reference current parameter corresponding to the permanent magnet wind driven generator, and taking an initial design parameter corresponding to the first reference working temperature as a target design parameter corresponding to the permanent magnet wind driven generator;

and if all the ratios are smaller than a second set threshold, taking the first reference working temperature as the target reference working temperature of the permanent magnet, and taking the initial design parameters corresponding to the target reference working temperature as the target design parameters corresponding to the permanent magnet wind driven generator.

The following specifically describes the design principle of the permanent magnet wind turbine of the present embodiment:

s1, performing initial design of the permanent magnet wind driven generator according to the design target A and the constraint condition B1, wherein the specific design process is as follows:

s1.1, determining an initial size parameter of the permanent magnet wind driven generator according to a design target A and a second constraint condition B1.2;

s1.2, according to a first constraint condition B1.1, assuming the working temperature of the generator component (comprising a winding and a permanent magnet), and determining the physical property of the electromagnetic material according to the working temperature; adjusting the input current to enable the initial design to meet the design target A, and calculating the electromagnetic performance;

s1.3, under the condition that the design target A is met and the envelope size in the S1.1 is not changed, performing single/multi-objective optimization on the internal size of the permanent magnet wind driven generator to obtain an optimal internal size parameter;

s1.4, inputting the loss of the permanent magnet wind driven generator into a heat dissipation model to calculate the actual temperature of each component according to a design scheme corresponding to the optimal internal dimension parameter, updating the physical property of an electromagnetic material in the electromagnetic model according to the actual temperature, readjusting input current to meet a design target A, and repeating iteration until the assumed working temperature of each component in the electromagnetic model is consistent with the actual working temperature of each component calculated by the heat dissipation model;

s1.5, checking whether the actual working temperature of the winding meets a first constraint condition B1.1 through a heat dissipation model, if so, further determining the insulation grade of the winding, and if not, returning to the step S1.1, and re-determining the envelope size and the internal size parameter;

s1.6, carrying out demagnetization check on the current design scheme, comprising the following steps: calculating the demagnetization condition of the permanent magnet under the demagnetization influence event (or extreme condition), wherein the demagnetization influence event comprises a short circuit condition and an overload condition,

if the demagnetization volume ratio of the permanent magnet under at least one demagnetization influence event is larger than the threshold value alpha 1, and alpha 1 is more than or equal to 0 and less than 1, returning to the step S1.1, and re-determining the internal dimension parameter, or keeping the envelope dimension unchanged and re-determining the internal dimension parameter; otherwise, the current design is used as a final initial design scheme Z, the initial design scheme Z is used as a reference design scheme Y, and the step S2 is carried out;

s2, according to the probability information of the demagnetization influencing events, k situations of the demagnetization influencing events occurring in the whole life cycle n (such as 20 years) are given, wherein the jth situation co-occurs the demagnetization influencing event m_jWherein j is more than or equal to 1 and less than or equal to k, m_j≥1；

S3, under a first constraint condition B1.1, determining a feasible working temperature range of the permanent magnet and h permanent magnet working temperature points in a variation range, wherein the upper limit of the variation range is determined by the first constraint condition B1.1, and the lower limit is determined by the permanent magnet working temperature of the current design scheme; specifically, the upper limit is less than or equal to the permanent magnet working temperature corresponding to the first constraint condition B1.1, the lower limit is less than or equal to the permanent magnet working temperature of the current design scheme, and the h permanent magnet working temperature points include the permanent magnet working temperature corresponding to the reference design scheme Y;

s4, determining the current corresponding to the working temperature points of the h permanent magnets in the step S3, including adjusting the loss through a heat dissipation model, so that the permanent magnets reach the working temperature points under a certain loss value, calculating the winding temperature according to the loss value, further obtaining the winding resistance under the winding temperature, finally obtaining the current according to the winding loss and the winding resistance, and then adjusting the current phase to reach the target voltage level in the design target A;

judging whether the rated grid-connected power is less than or equal to an upper limit value beta and more than or equal to the target rated grid-connected power in a design target A under the condition of current input corresponding to the target voltage grade, if so, calculating the electromagnetic performance (including current magnitude and phase, electromagnetic torque, back electromotive force, rated load terminal voltage and the like), and entering the step S5, otherwise, deleting the working temperature point, wherein the working temperature point does not enter the following step for calculation, h 'permanent magnet working temperature points are finally obtained through screening, and h' is less than or equal to h;

s5, calculating for each of the permanent magnet operating temperature points remaining in step S4 as follows:

according to the situation of the jth occurrence of the demagnetization influence event and the input power curve, calculating the actual rated grid-connected power after each occurrence of the demagnetization influence event in sequence, updating the physical property (namely, the demagnetization curve) of the permanent magnet electromagnetic material, and adjusting the current phase to meet the voltage grade in the design target A based on the physical property of the permanent magnet electromagnetic material after each occurrence of the demagnetization influence event until the mth occurrence of the demagnetization influence event is finished_jCalculating after the secondary demagnetization influence event, further obtaining and recording a Net Present Value (NPV) of the permanent magnet wind driven generator in the full life cycle under the j-th situation corresponding to the working temperature of the permanent magnet, and finally forming a NPV matrix of the net present values under the situations of multiple permanent magnet working temperatures and multiple demagnetization influence events, wherein the dimension of the NPV matrix of the net present values is h' × k;

s6, multiplying each element in the net present value NPV matrix in the step S5 by a coefficient mu to obtain an updated net present value NPV matrix, wherein the coefficient mu corresponds to a demagnetization influence event situation under a permanent magnet working temperature, and the coefficient mu is determined according to the following mode:

recording the number of years that the rated grid-connected power in n years of the full life cycle is greater than or equal to the lower limit value gamma as n ', wherein the coefficient mu is a non-decreasing function of n'/n, the value of mu is 0 to 1, and the lower limit value gamma is less than or equal to the target rated grid-connected power in the design target A;

s7, performing statistical treatment on the k NPV values corresponding to the working temperature points of each permanent magnet in the step S6 to obtain a statistical value, and marking the statistical value as NPV', wherein the statistical treatment can be expectation value calculation, quantile calculation and the like; finally, h 'group design schemes are obtained, and the working temperature points of the permanent magnets in each group of design schemes correspond to the NPV' one by one;

s8, comparing the NPV ' corresponding to the working temperature points of each group of permanent magnets in the step S7 with the NPV ' corresponding to the reference design scheme Y, and recording the NPV ' corresponding to the reference design scheme Y as the NPV_Y’；

If there is at least one NPV'/NPV_Y'more than or equal to alpha 2, selecting the design scheme corresponding to the maximum value of the NPV' as a new reference design scheme Y, and entering the step S9;

if at least one alpha 3. ltoreq. NPV'/NPV_Y'alpha 2, selecting the design scheme corresponding to the maximum value of NPV' as the final scheme and quitting the design, otherwise, selecting the reference design scheme Y as the final design scheme and quitting the design, wherein alpha 2 is more than alpha 3 and is more than or equal to 1,

in addition, if at least two equal maximum values exist in the process of selecting the maximum value of NPV', the scheme with the lowest working temperature of the permanent magnet is selected as a new reference design scheme Y.

In this embodiment, the design scheme of the permanent magnet wind turbine is designed based on the new operating temperature, and the target of achieving the rated grid-connected power is not achieved, but the rated grid-connected power is optimized (or other targets) again, and the corresponding optimization design scheme is finally completed.

The above is further illustrated in detail by the following specific examples:

s1, carrying out initial design on the permanent magnet direct-drive outer rotor wind driven generator according to the design target A and the constraint condition B1, wherein the design process is as follows:

s1.1, designing a target A to be rated grid-connected power of 7.3MW, rated rotating speed of 10.3rpm and voltage level of 720V, preferably, considering a second constraint condition B1.2 to be processing and transportation limit, and using a modular stator structure and integer slot winding distribution, determining initial design parameters of the permanent magnet direct-drive outer rotor wind driven generator as shown in the following table 1 (simultaneously see FIG. 5), wherein the outer diameter and the axial effective length of a rotor are envelope size parameters, and each 6 poles correspond to one stator module and 24 stator modules in total.

TABLE 1 initial parameters of permanent magnet direct-drive external rotor wind driven generator

Parameter(s)	Value of	Parameter(s)	Value of
				Outer diameter of rotor	6491mm	Effective length in axial direction	1638mm
Stator bore	6080mm	Inner diameter of rotor	6350mm
				Width of groove	24mm	Depth of groove	95mm
Air gap length	7.5mm	Thickness of permanent magnet	23mm

S1.2, preferably, the first constraint B1.1 is a winding insulation level limit, under which the winding working temperature in the generator component is assumed to be 120 ℃ and the permanent magnet working temperature is 50 ℃, and the electromagnetic material physical properties are determined accordingly, wherein the material characteristics of the permanent magnet at a specific temperature mainly refer to a demagnetization curve, as shown by a curve indicated by 50 ℃ in fig. 6. In the present embodiment, the permanent magnet material used is N45H, which has a good demagnetization resistance, and the relationship between the demagnetization curve and the temperature is shown in fig. 6, where the horizontal axis represents the magnetic field strength (kA/m) and the vertical axis represents the magnetic flux density (T); the material characteristics of the generator winding mainly refer to the relation of resistance change along with temperature, and the expression is as follows:

R＝R₂₀[1+(T-20)×0.004％]

wherein R is₂₀The resistance value at 20 ℃ is T, which is 120 in the present embodiment, and the winding operating temperature is T. It should be noted that, in this embodiment, the winding operating temperature and the permanent magnet operating temperature are both the highest operating temperature under the rated operating condition.

According to the characteristics of the electromagnetic materials, the input current is adjusted, when the current amplitude is 6835A and the current angle is-198.8 degrees, the design target A is met, and the rated grid-connected power is 7.3MW, the rated rotating speed is 10.3rpm and the voltage level is 720V are obtained through calculation. The input current is the phase current, and the current angle (corresponding to the current phase) is the included angle between the current and the no-load back electromotive force of the motor.

S1.3, under the condition that the design target A is met and the envelope size in the S1.1 is not changed, a genetic algorithm is adopted, the rated output power is taken as a target, the single-target optimization is carried out on the internal size of the permanent magnet direct-drive external rotor wind driven generator and the permanent magnet direct-drive external rotor wind driven generator, and the optimal internal size parameters are obtained as shown in the following table 2:

TABLE 2 optimized parameters of permanent-magnet direct-drive external rotor wind driven generator

Parameter(s)	Value of	Parameter(s)	Value of
				Stator bore	6084mm	Inner diameter of rotor	6370mm
Width of groove	23mm	Depth of groove	96.8mm
				Air gap length	7.5mm	Thickness of permanent magnet	22mm

S1.4, readjusting the current to obtain the current amplitude 6788A corresponding to the design scheme of the optimal internal dimension parameter shown in the table 2, meeting the design target A when the current angle is-198.6 degrees, further calculating the loss of the permanent magnet direct-drive outer rotor wind driven generator, as shown in the table 3, inputting the loss of each part into a heat dissipation model to calculate the actual temperature of each part to obtain the actual working temperature of a winding of 130 ℃ and the actual working temperature of a permanent magnet of 58 ℃, updating the physical property of the electromagnetic material in the electromagnetic model according to the actual temperature, readjusting the input current, meeting the design target A when the current amplitude is 6742A and the current angle is-198.4 degrees, recalculating the loss and the actual temperature of each part, iterating repeatedly until the assumed working temperature of each part in the electromagnetic model is consistent with the actual working temperature of each part calculated by the heat dissipation model, and finally obtaining the winding temperature of 132 ℃, the working temperature of the permanent magnet is 60 ℃, the current amplitude is 6617A, and the current angle is-198.2 degrees.

TABLE 3 losses after optimization of permanent magnet direct-drive external rotor wind turbine and before iteration of heat dissipation model

Parameter(s)	Value (kW)	Parameter(s)	Value (kW)
				Stator iron loss	34.56	Rotor loss	3.5
Loss of finger plate	14	Harmonic loss	11.67
				Bearing wear	20.77	Loss of cable	8.86
Loss of converter	252.73	Auxiliary losses	71

S1.5, the actual working temperature 132 ℃ of the winding obtained in the step S1.4 meets the requirement of the highest C-level insulation in the first constraint condition B1.1, and the actually used winding insulation grade is further determined to be F-level insulation.

S1.6, performing demagnetization verification on the permanent magnet under the demagnetization influencing event, taking as an example that one of the demagnetization influencing events which causes the most serious demagnetization is a three-phase short circuit, and the corresponding demagnetization region is as shown in fig. 3, and the demagnetization volume ratio is smaller than the threshold α 1 by 0.2%, so that the current design is taken as the final initial design scheme Z, the initial design scheme Z is taken as the reference design scheme Y, and the process proceeds to step S2.

S2, according to the statistical data, the typical life cycle of the permanent-magnet direct-drive external-rotor wind turbine is 20 years, and about 5 demagnetization-affecting events occur in the full life cycle, in this embodiment, the demagnetization-affecting events are all three-phase short circuits, and assuming that each demagnetization-affecting event occurs at the end of each year, 10 cases where the demagnetization-affecting event occurs are selected as the basis for the calculation in the subsequent step, and 5 demagnetization-affecting events, that is, m, occur in each case_jJ.ltoreq.1.ltoreq.10 as shown in Table 4. It should be noted that, in this embodiment, the occurrence time of the demagnetization affecting event is in units of years, and according to the actual situation, a smaller time unit, such as in units of months, may be taken, so that the evaluation result is more reliable and accurate. Of course, the selected parameters can be redesigned and adjusted according to actual requirements.

S3, under the requirement of a C-level insulation grade of a first constraint condition B1.1, when the rated current of the generator is 8400A, the temperature of the corresponding winding reaches the upper limit of 220 ℃, and the working temperature of the permanent magnet at the moment is calculated to be 85 ℃ according to a heat dissipation model, so that the upper limit of the feasible working temperature range of the selected permanent magnet is 85 ℃. Meanwhile, the lower limit of the feasible working temperature range of the permanent magnet is selected to be 60 ℃, 5 ℃ is taken as a step length, and h which is 6 permanent magnet working temperature points in the feasible working temperature range of the permanent magnet is selected in an equal difference mode to be 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃ and 85 ℃, wherein the h which is 6 permanent magnet working temperature comprises 60 ℃ of the first reference working temperature of the permanent magnet corresponding to the current reference design scheme Y.

S4, adjusting the loss so that the permanent magnet reaches the 6 permanent magnet temperature operating points listed in step S3 at a certain loss value, for example, the relationship between the dc copper loss and the permanent magnet temperature shown in fig. 7, further calculating the winding temperature according to the dc copper loss value, as shown in fig. 8, further calculating the winding resistance at the winding temperature according to the formula in step s.12, as shown in fig. 9, and finally obtaining the current magnitude according to the dc copper loss and the winding resistance, as shown in fig. 10. The current phase is adjusted according to the condition of the voltage level 720V in the design target a, as shown in fig. 11. Based on the above results, the rated grid-connected power of the generator at the preset working temperature of each permanent magnet is obtained, as shown in fig. 12, it is determined whether the rated grid-connected power at the working temperature of each permanent magnet is less than or equal to the upper limit value β of the rated grid-connected power of 8.5MW and greater than or equal to the rated grid-connected power of 7.3MW in the design target a, it can be seen that the rated grid-connected power corresponding to the working temperatures of 6 permanent magnets all meet the requirements, and finally, h' ═ 6 permanent magnet temperature working points are obtained, so that all the calculation in the next step is performed.

S5, calculating the h' ═ 6 permanent magnet operating temperature points in step S4 as follows:

taking the permanent magnet working temperature of 70 ℃ and the j-th situation of 1 kind of demagnetization influencing events in the step S2 as an example, the rated grid-connected power after each demagnetization influencing event is generated is sequentially calculated, and based on the physical properties of the permanent magnet electromagnetic material after each demagnetization influencing event is generated, as shown in fig. 13, the rated current amplitude is kept unchanged, and the current phase is adjusted to meet the voltage level in the design target a. Until m is completed₁The rated grid-connected power after each demagnetization influence event is obtained by calculation after 5 demagnetization influence events, and is shown in a 70 ℃ corresponding curve in fig. 13.

Further obtaining and recording NPV (net present value) of the full life cycle of the permanent magnet direct-drive outer rotor wind driven generator under the condition that j is equal to 1 corresponding to different working temperatures of the permanent magnet, wherein the expression of the NPV is as follows:

wherein, P_iIs the output power (kW) at a certain wind speed, T_iThe hour number (unit is h) of a certain wind speed in one year, s is the selling price of electricity per degree, and C is the cost of the permanent magnet wind driven generator. P_iThe calculation method comprises the following steps: for nominal operation, i.e. at nominal speed, P_iI.e. rated grid-connected power as shown in fig. 14, for the non-rated working condition, P_iIs expressed as

P_i＝P_in-P_cop-P_fe-P_fin-P_h-P_cab-P_con-P_aux

Wherein, P_inFor input power, P_copFor copper consumption, P_feFor iron loss, P_finFor loss of finger plate, P_hFor harmonic losses, P_cabFor cable losses, P_conFor converter losses, P_auxTo assist in the losses. Input power P_inAs shown in fig. 16, the copper loss is obtained by multiplying the resistance by the square of the current, and other losses can be obtained by finite element software or empirical formulas. T is_iAs in FIG. 15; manufacturing costs of permanent magnet wind turbines include, but are not limited to, generator stator and rotor core costs, winding costs, permanent magnet costs, housing costs, bearing costs, generator support costs, blade costs, converter costs, cable costs, heat dissipation system costs, transportation and installation costs. Optionally, in order to simplify the calculation, it is assumed in the present embodiment that the above cost remains unchanged during the design process; optionally, in order to improve the NPV calculation accuracy, the above cost varies with the size of the generator, the insulation grade, and the installation and transportation method during the design process. In summary, the NPV and the permanent magnet temperature in the j-th 1 demagnetization-affecting event are obtainedThe curve of (a) is shown in fig. 17.

Similarly, NPVs of the permanent magnet direct-drive outer rotor wind turbine generator in all k cases (k is 10) can be calculated, and finally, an NPV matrix is formed as follows, wherein NPV rows from the 1 st row to the 6 th row correspond to 6 permanent magnet working temperature points of 60 ℃ to 85 ℃, and columns from the 1 st column to the 10 th column respectively correspond to NPV values in the cases from the 1 st column to the 10 th column under the demagnetization influence event.

S6 shows that the loss of the generated power due to demagnetization within a certain range is acceptable for the permanent magnet wind turbine, and therefore the rated grid-connected power is allowed to be equal to or greater than the lower limit γ for a full life cycle n of 20 years. For convenience of calculation, the lower limit value gamma of the rated grid-connected power is equal to the rated grid-connected power of 7.3MW in the design target A. For the condition that the rated grid-connected power is smaller than the lower limit value after demagnetization, namely the rated grid-connected power is not in an acceptable range after demagnetization, the NPV needs to be corrected and then compared with NPVs under other conditions, so that the disadvantage of the rated grid-connected power after demagnetization is represented. The number of years in which the rated grid-connected power in the full life cycle n is 20 years is greater than or equal to the lower limit value γ of 7.3MW is denoted as n ', the correction coefficient μ is a non-decreasing function of n'/n, and μ takes a value of 0 to 1, in this embodiment, a direct proportional function with a slope of 1 as shown in fig. 18 is adopted, and the function may be a step function as shown in fig. 19 or other functions meeting the requirements.

When the permanent magnet temperature is 85 ℃, as shown in fig. 15, when the first demagnetization influencing event occurs, the total n' ═ 16 years rated grid-connected power is equal to or greater than the lower limit value γ ═ 7.3MW, and according to fig. 18, when the permanent magnet temperature is 85 ℃, the coefficient μ corresponding to NPV when the first demagnetization influencing event occurs is 16/20 ═ 0.8. If the working temperature of the permanent magnet is 60 ℃, all 10 demagnetization influencing events occur within a full life cycle of n-20 years, and the years with rated grid-connected power larger than or equal to a lower limit value of γ -7.3 MW are n' -20, then μ is 20/20-1, and finally a correction coefficient μmatrix is obtained as follows:

and multiplying the correction coefficient mu matrix and the NPV matrix point to obtain a corrected NPV matrix as follows.

S7, performing statistical processing on each row k of the corrected NPV matrix, where the statistical processing in this embodiment uses an average value, to obtain a corrected NPV average value NPV 'at h' of 6 permanent magnet operating temperatures, as shown in fig. 20.

S8, comparing the NPV ' corresponding to the working temperature points of each group of permanent magnets in the step S7 with the NPV ' corresponding to the reference design scheme Y, and recording the NPV ' corresponding to the reference design scheme Y as the NPV_Y' (i.e., NPV ' at 60 ℃ C.) to obtain NPV '/NPV_YThe curve of' is shown in figure 21. In this example, α 2 is 1.05, α 3 is 1.03, and if there is at least one NPV'/NPV_Y' > α 2 ≧ 1.05, which is taken as a new reference design Y in order to obtain a higher generator NPV; if at least one 1.03 ═ alpha 3 ≦ NPV'/NPV_Y'alpha 2 is 1.05, in order to reduce the calculation amount and the design period, the design scheme corresponding to the maximum value of NPV' is selected as the final scheme, and the design is quit; otherwise, in order to ensure the reliability of the permanent magnet generator, the reference design scheme Y is selected as the final design scheme. According to FIG. 21, none of the design solutions NPV'/NPV was found_Y'> alpha 2 ≥ 1.05, and when the working temperature of permanent magnet is 70 deg.C and 75 deg.C, 1.03 ≥ alpha 3 ≤ NPV'/NPV_Y'alpha 2 is 1.05, and the maximum NPV' is the design scheme when the working temperature of the permanent magnet is 75 ℃, so the design scheme is selected as the final design and the design is exited.

Example 3

As shown in fig. 22, the design system of the permanent magnet wind turbine of the present embodiment includes:

the temperature range acquisition module 1 is used for determining a feasible working temperature range of the permanent magnet based on a design target, a first constraint condition and a second constraint condition;

the first constraint condition is used for limiting the insulation grade of a generator winding, and the second constraint condition is used for limiting the design size of the generator;

In an embodiment, the plurality of preset operating temperature points include a first reference operating temperature and are arranged with equal difference. Of course, redesign and adjustment can be performed according to actual requirements.

The temperature point selection module 2 is used for selecting a plurality of preset working temperature points within a feasible working temperature range;

the parameter presetting module 3 is used for presetting a plurality of demagnetization influencing events, the occurrence frequency of each demagnetization influencing event in a set full life cycle and the occurrence time corresponding to each occurrence;

The actual power acquisition module 4 is used for respectively acquiring the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after each occurrence time of the demagnetization influence event for each demagnetization influence event in the set full life cycle;

the first associated parameter acquiring module 5 is used for acquiring first power generation associated parameters of the permanent magnet wind driven generator at each preset working temperature point;

the second associated parameter acquiring module 6 is used for acquiring a second power generation associated parameter corresponding to the permanent magnet at the first reference working temperature;

the comparison module 7 is used for comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result;

and the target parameter obtaining module 8 is used for determining a target design parameter corresponding to the permanent magnet wind driven generator based on the comparison result.

Specifically, the comparing module 7 is configured to compare the first power generation related parameter with the second power generation related parameter to obtain a comparison result; judging whether the comparison result is larger than the upper limit value of the preset range, if so, calling a target parameter acquisition module 8 to select a preset temperature working point corresponding to a first power generation related parameter which is ranked earlier to update to obtain a new first reference working temperature to serve as the target reference working temperature of the permanent magnet, adopting the target reference working temperature to redesign a target design parameter corresponding to the permanent magnet wind driven generator, and calling a temperature range acquisition module 1; if not, judging whether the comparison result falls into a preset range or not, if so, calling a target parameter acquisition module 8 to select a preset temperature working point corresponding to a first power generation associated parameter in the front sequence to update a first reference working temperature and/or a first reference current parameter corresponding to the permanent magnet wind driven generator, and taking an initial design parameter corresponding to the selected preset temperature working point as a target design parameter corresponding to the permanent magnet wind driven generator; if the comparison result is smaller than the lower limit value of the preset range, calling the target parameter obtaining module 8 to use the first reference working temperature corresponding to the second power generation related parameter as the target reference working temperature of the permanent magnet, and using the initial design parameter corresponding to the target reference working temperature as the target design parameter corresponding to the permanent magnet wind power generator.

Example 4

The design system of the permanent magnet wind power generator of the present embodiment is a further improvement of embodiment 3, specifically:

in an embodiment, the temperature range obtaining module 1 of the present embodiment includes:

the size parameter determining unit is used for determining size reference parameters of the permanent magnet wind driven generator based on the design target and the second constraint condition;

where single or multiple targets include efficiency, power factor, cost, etc.

The loss parameter acquisition unit is used for adjusting and acquiring an input current parameter reaching a design target based on the optimized size reference parameter, and calculating to obtain a loss parameter associated with the generator based on the input current parameter;

and the initial parameter obtaining unit is used for iteratively adjusting the input current parameters based on the loss parameters and the heat dissipation model until obtaining the working temperature of the permanent magnet correspondingly reaching the design target under the initial design and the feasible working temperature range under the first constraint condition.

In addition, in order to avoid the situation of demagnetization of the permanent magnet, the demagnetization volume ratio of the permanent magnet under each demagnetization influence event can be obtained; and when the demagnetization volume ratio is larger than a first set threshold, adjusting the size reference parameter until the demagnetization volume ratio of the permanent magnet under each demagnetization influence event is smaller than the first set threshold, and acquiring the adjusted size reference parameter.

In an embodiment, the design system of this embodiment further includes:

the loss value acquisition module is used for adjusting the set loss based on the heat dissipation model and acquiring a corresponding loss value when the working temperature of the permanent magnet is adjusted to a preset working temperature point;

the winding temperature calculation module is used for calculating to obtain the winding temperature corresponding to the generator winding based on the loss value;

the current parameter adjusting module is used for adjusting the current phase in the input current so as to meet the target voltage level under the design target; the rated current is the current under the first rated grid-connected power corresponding to each preset working temperature point of the wind driven generator.

and the target rated grid-connected power screening module is used for screening out a target rated grid-connected power in which the first rated grid-connected power is greater than or equal to the design target and screening out a preset working temperature point which is less than the maximum rated grid-connected power.

In an embodiment, the actual power obtaining module of this embodiment includes:

the demagnetization curve acquisition unit is used for respectively acquiring a demagnetization curve corresponding to the permanent magnet at each preset working temperature point after a demagnetization influence event occurs at each occurrence time;

the current adjusting unit is used for adjusting the current phase of the rated current of the wind driven generator based on the demagnetization curve so as to meet the target voltage level under the design target;

and the actual power obtaining unit is used for calculating to obtain the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after demagnetization based on the regulated rated current and the demagnetization curve of the permanent magnet after demagnetization.

The first associated parameter acquisition module is used for calculating to obtain a net present value NPV of the permanent magnet wind driven generator at each preset working temperature point based on the duration of different wind speeds in a set time period, the electricity consumption unit price and the manufacturing cost of the generator;

In an embodiment, the design system further comprises:

the power calculation module is used for calculating and obtaining the grid-connected power of the generator at different wind speeds based on different wind speeds and the rotor loss at the corresponding wind speed;

the power calculation module is also used for adjusting the phase of the current and keeping the current unchanged until the target voltage grade under the design target is met after each demagnetization influence event occurs under the condition of the rated wind speed, and calculating the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after demagnetization;

the power calculation module is also used for calculating the grid-connected power after the demagnetization influence event occurs by adopting the current magnitude and the phase corresponding to the generator when no demagnetization influence event occurs under the condition of non-rated wind speed; or compensating the generated energy of the generator by adopting a current compensation mode until the generated energy corresponding to the generator is generated when any demagnetization influence event does not occur.

In an embodiment, the design system of this embodiment further includes:

the comparison module is used for calculating to obtain the ratio of different first processing values NPV and second processing values NPV, judging whether the ratio is larger than a first set threshold value or not, selecting a corresponding preset working temperature point to update to obtain a new first reference working temperature to serve as a target reference working temperature of the permanent magnet, adopting the target reference working temperature to redesign to obtain a target design parameter corresponding to the permanent magnet wind driven generator, and calling the temperature range acquisition module;

otherwise, the comparison module is used for judging whether the ratio is smaller than or equal to a first set threshold and larger than or equal to a second set threshold, if so, the target parameter acquisition module is called to select a preset working temperature point corresponding to the highest ratio as a target reference working temperature of the permanent magnet, the target reference working temperature is used as a first reference working temperature and/or a first reference current parameter corresponding to the permanent magnet wind driven generator, and an initial design parameter corresponding to the first reference working temperature is used as a target design parameter corresponding to the permanent magnet wind driven generator;

and the comparison module is used for taking the first reference working temperature as the target reference working temperature of the permanent magnet and taking the initial design parameters corresponding to the target reference working temperature as the target design parameters corresponding to the permanent magnet wind driven generator if all the ratios are smaller than the second set threshold.

The implementation principle of the design system of the permanent magnet wind turbine of this embodiment is similar to the design method of embodiment 2, and therefore, the detailed description thereof is omitted here.

Example 5

Fig. 23 is a schematic structural diagram of an electronic device according to embodiment 5 of the present invention. The electronic device comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, and the processor executes the program to realize the design method of the permanent magnet wind power generator in any one of the

embodiments

1 or 2. The electronic device 30 shown in fig. 23 is only an example, and should not bring any limitation to the functions and the scope of use of the embodiment of the present invention.

As shown in fig. 23, the electronic device 30 may be embodied in the form of a general purpose computing device, which may be, for example, a server device. The components of the electronic device 30 may include, but are not limited to: the at least one processor 31, the at least one memory 32, and a bus 33 connecting the various system components (including the memory 32 and the processor 31).

The bus 33 includes a data bus, an address bus, and a control bus.

The memory 32 may include volatile memory, such as Random Access Memory (RAM)321 and/or cache memory 322, and may further include Read Only Memory (ROM) 323.

Memory 32 may also include a program/utility 325 having a set (at least one) of program modules 324, such program modules 324 including, but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which, or some combination thereof, may comprise an implementation of a network environment.

The processor 31 executes various functional applications and data processing by running a computer program stored in the memory 32, for example, a design method of a permanent magnet wind turbine in any one of the

embodiments

1 or 2 of the present invention.

The electronic device 30 may also communicate with one or more external devices 34 (e.g., keyboard, pointing device, etc.). Such communication may be through input/output (I/O) interfaces 35. Also, model-generating device 30 may also communicate with one or more networks (e.g., a Local Area Network (LAN), a Wide Area Network (WAN), and/or a public network, such as the Internet) via network adapter 36. As shown in FIG. 23, network adapter 36 communicates with the other modules of model-generating device 30 via bus 33. It should be understood that although not shown in the figures, other hardware and/or software modules may be used in conjunction with the model-generating device 30, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems, etc.

It should be noted that although in the above detailed description several units/modules or sub-units/modules of the electronic device are mentioned, such a division is merely exemplary and not mandatory. Indeed, the features and functionality of two or more of the units/modules described above may be embodied in one unit/module according to embodiments of the invention. Conversely, the features and functions of one unit/module described above may be further divided into embodiments by a plurality of units/modules.

Example 6

The present embodiment provides a computer-readable storage medium on which a computer program is stored, the program, when executed by a processor, implementing the steps in the design method of the permanent magnet wind turbine in any one of

embodiments

1 or 2.

More specific examples, among others, that the readable storage medium may employ may include, but are not limited to: a portable disk, a hard disk, random access memory, read only memory, erasable programmable read only memory, optical storage device, magnetic storage device, or any suitable combination of the foregoing.

In a possible embodiment, the invention may also be implemented in the form of a program product comprising program code for causing a terminal device to perform the steps of the method of designing a permanent magnet wind turbine according to any of

embodiments

1 or 2, when the program product is run on the terminal device.

Where program code for carrying out the invention is written in any combination of one or more programming languages, the program code may execute entirely on the user device, partly on the user device, as a stand-alone software package, partly on the user device and partly on a remote device or entirely on the remote device.

While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.

Claims

1. A design method of a permanent magnet wind power generator is characterized by comprising the following steps:

2. The method of claim 1, wherein the step of comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result, and determining the corresponding target design parameter of the permanent magnet wind turbine based on the comparison result comprises:

3. The method according to claim 1 or 2, wherein after the step of selecting a plurality of preset operating temperature points within the feasible operating temperature range, the step of respectively obtaining the actual rated grid-connected power of the permanent magnet at each preset operating temperature point after the demagnetization influencing event occurs at each occurrence time further comprises:

calculating a winding resistance value based on the winding temperature;

screening out the first rated grid-connected power which is greater than or equal to the target rated grid-connected power in the design target, and screening out a preset working temperature point which is less than the maximum rated grid-connected power.

4. The design method of the permanent magnet wind power generator according to claim 3, wherein the step of respectively obtaining the corresponding actual rated grid-connected power of the permanent magnet at each preset working temperature point after the demagnetization influencing event occurs at each occurrence time comprises:

5. The method of claim 4, wherein the step of obtaining the first power generation related parameter of the permanent magnet wind turbine at each of the preset operating temperature points comprises:

6. The method of claim 5, wherein said step of calculating a net present value NPV of said permanent magnet wind turbine at each of said predetermined operating temperature points is preceded by the steps of:

7. The method of claim 5, wherein the step of comparing the first power generation related parameter with the second power generation related parameter to obtain a comparison result and determining the corresponding target design parameter of the permanent magnet wind turbine based on the comparison result comprises:

8. The method of designing a permanent magnet wind turbine according to claim 1, wherein the design objectives include a target rated grid-connected power, a target rated rotational speed, and a target voltage level;

9. The method of claim 1, wherein the plurality of predetermined operating temperature points comprise the first reference operating temperature and are arranged at equal differences from each other; and/or the presence of a gas in the gas,

10. A design system for a permanent magnet wind turbine, the design system comprising:

11. A permanent magnet wind generator, characterized in that it comprises a design system of a permanent magnet wind generator according to claim 10.

12. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor, when executing the computer program, implements the method of designing a permanent magnet wind turbine according to any of claims 1-9.

13. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the method of designing a permanent magnet wind turbine according to any of claims 1-9.