CN108364775A - Energy taking device and its design method based on converter valve busbar square wave current - Google Patents

Abstract

The present invention relates to an energy harvesting device based on the square wave current of the converter valve busbar and a design method thereof. The method includes the following steps: S1: extracting key parameters of the square wave current of the converter valve busbar; S2: calculating the energy harvesting device Power characteristics of the coil; S3: Select the magnetic core material and shape of the energy harvesting device according to the shape of the converter valve busbar, and analyze and calculate the energy harvesting device; S4: Simulate the designed energy harvesting device, and build a test platform to Energy harvesting device for performance testing. The present invention proposes a design method of a high-performance high-voltage side induction energy harvesting device through theoretical analysis, simulation research and experimental testing of various parameters of the magnetic core and signal processing circuit based on the principle of electromagnetic induction.

Description

Energy harvesting device and its design method based on square wave current of converter valve busbar

technical field

The invention belongs to the technical field of electric energy conversion equipment, and relates to a design method of an energy harvesting device based on the square wave current of a bus bar of a converter valve.

Background technique

With the continuous development and improvement of the power system and the rapid development of the power grid, the current scale of my country's power grid has leapt to the first place in the world, but there is a reverse distribution contradiction between the distribution of energy resources and energy demand in our country, which has caused the power generation energy and power load in our country to distribution is extremely uneven. In order to overcome the contradiction of energy structure, the State Grid Corporation put forward the strategic goal of "building a unified strong smart grid". The high-voltage direct current grid has a series of advantages such as large transmission capacity, small loss, and long transmission distance, which determine that it is an important carrier for large-capacity long-distance transmission in a strong smart grid framework.

The converter valve is the core equipment of the UHV DC transmission system. Once a fault occurs, it will greatly affect the operation reliability of the UHV DC grid.

The long-term operation of the converter valve in a complex environment intertwined with multiple physical fields such as electricity, magnetism and heat determines the relatively weak operating reliability of the converter valve. Because the operating voltage level of the converter valve is too high, it is impossible to directly observe the operating status of the converter valve equipment at close range, which makes it impossible for the operator to know the operating status of each part of the converter valve equipment at the first time, which may lead to Flow valve equipment "running sick". This brings great risks to the operation of the converter valve, even if the failure probability is extremely small, it may cause great economic losses.

In order to make timely status assessment and fault diagnosis of converter valve equipment and better ensure the normal operation of the equipment, it is necessary to establish a complete online monitoring and status assessment and diagnosis system. The sensors of the online monitoring system and the processing and transmission of monitoring data all need a stable energy harvesting device. Therefore, it is of great significance to study a set of practical energy harvesting devices for the online monitoring system.

At present, the online energy harvesting devices reported in the literature are mainly applied to the online monitoring system under the sinusoidal current condition of the AC transmission system. However, since the current flowing through the busbar of the DC converter valve is a square wave current, in order to provide a long-term reliable low-voltage power supply for the on-line monitoring system of the converter valve, the square wave current of the busbar of the converter valve, which is a special It is of great significance to analyze and design the induction energy harvesting method of working conditions.

Contents of the invention

In view of this, the object of the present invention is to provide an energy harvesting device based on the square wave current of the converter valve busbar and its design method, by theoretically analyzing the parameters of the magnetic core and signal processing circuit based on the principle of electromagnetic induction , simulation research and experimental testing, a high-performance high-voltage side induction energy harvesting device is designed.

To achieve the above object, the present invention provides the following technical solutions:

A method for designing an energy harvesting device based on the square wave current of the converter valve busbar, the method includes the following steps:

S1: Extract the key parameters of the square wave current of the busbar of the converter valve;

S2: Calculate the power characteristics of the coil of the energy harvesting device;

S3: Select the magnetic core material and shape of the energy harvesting device according to the shape of the converter valve busbar, and analyze and calculate the energy harvesting device;

S4: Simulate the designed energy harvesting device, and build a test platform to test the performance of the energy harvesting device.

Further, step S2 specifically includes the following steps:

S21: Calculate the effective value of the secondary side voltage of the energy harvesting device;

S22: Calculate the secondary side power characteristics of the energy harvesting device.

Further, the shape of the iron core in step S3 is a U-shaped ring or a circular ring.

Further, step S3 is specifically:

S31: Select the magnetic core material according to the magnetic permeability, coercive force, resistivity and saturation magnetic induction of the magnetic core material;

S32: Analyze the magnetic resistance and magnetic saturation of the magnetic core, and determine the size of the magnetic core;

S33: Calculate the coil turns of the energy harvesting device;

S34: Design the inter-turn insulation of the coil of the energy harvesting device.

Further, step S32 is specifically:

S321: Select a circular magnetic core, assume that the magnetic core works in a linear region, and calculate the magnetic core permeability;

S322: Calculate the maximum excitation current when just entering the saturation state;

S323: Design the size of the magnetic core according to the principle that the sum of the average magnetic path length and the perimeter of the cross-sectional area is the smallest.

Further, the number of coil turns of the energy-taking device in step S33 satisfies:

Among them, e is the induced potential, n is the number of turns of the coil, μ _eq is the equivalent magnetic permeability, w is the width of the inner diameter and outer diameter of the iron core, and s is the thickness of the iron core.

Further, step S4 is specifically:

S41: Modeling the magnetic core according to the magnetic core parameters, and connecting the magnetic core to an excitation source;

S42: Set the excitation source as a power frequency current, and change the amplitude of the applied power frequency current, conduct a no-load test on the primary side of the magnetic core, test and record the output voltage amplitude of the secondary side of the magnetic core;

S43: Replace the power frequency current with a square wave current with a fixed amplitude, conduct a no-load test on the primary side of the magnetic core, test and record the output voltage amplitude of the secondary side of the magnetic core;

S44: connect the secondary side of the magnetic core to the signal processing module to form an energy-taking circuit, and connect to the load equivalent circuit;

S45: apply excitation and change the resistance value of the load equivalent resistance, test the change of the load terminal voltage, and make statistics to draw a conclusion;

S46: Build the test platform, debug the test circuit, test the designed energy harvesting device, and obtain the performance of the energy harvesting device in the real environment.

Further, the signal processing module includes a rectification circuit, a filter capacitor and a voltage stabilization circuit connected in sequence, the rectification circuit is connected to the secondary side of the magnetic core, and the voltage stabilization circuit is connected to the load equivalent circuit.

The energy harvesting device based on the square wave current of the busbar of the converter valve, the magnetic core of the energy harvesting device is in the shape of a ring with opposite openings, and is divided into a primary side magnetic core and a secondary side magnetic core, and is wound with a primary side coil and a secondary side coil respectively. As for the secondary side coil, the magnetic core is made of silicon steel sheet, and air gap sheets are arranged at the two openings, which are compressed by spring circlips. The energy harvesting device is used to extract line parameters from high-voltage lines.

Further, the turn-to-turn insulation of the primary side coil and the secondary side coil is made of polyester film.

The beneficial effect of the present invention is that: through theoretical analysis, simulation research and experimental testing of the energy harvesting magnetic core based on the principle of electromagnetic induction energy harvesting and various parameters of the signal processing circuit, a high-voltage side induction harvester with better performance is designed. energy structure.

(1) Modeling and simulating the magnetic core Using Ansoft Maxwell to establish C-shaped and U-shaped closed magnetic cores and open air-gapped magnetic core models, simulation analysis of the main factors affecting the output power, using the appropriate width of the core interface to add air The gap scheme is used to prevent the core from entering the saturation state prematurely. When the bus current is large, the energy-taking magnetic core still works in a non-saturated state, thus providing sufficient energy for the back-end equipment.

(2) Experimental tests were carried out on the designed signal processing module of the inductive power supply. An experimental platform was built in the laboratory, and the processing circuit was welded and debugged. The experiment waveform is analyzed to confirm the feasibility of the circuit.

Description of drawings

In order to make the purpose, technical scheme and beneficial effect of the present invention clearer, the present invention provides the following drawings for illustration:

Fig. 1 is a flowchart of the present invention;

Fig. 2 is a schematic diagram of the energy harvesting device of the present invention;

Fig. 3 is the schematic diagram of the magnetic core shape of the embodiment of the present invention;

Fig. 4 is the simulation schematic diagram showing the magnetic core shape of the embodiment of the present invention;

Fig. 5 is a schematic diagram of a cross-sectional structure of a circular magnetic core according to an embodiment of the present invention;

Fig. 6 is a schematic diagram of the no-load current and voltage relationship of the energy harvesting device according to the embodiment of the present invention;

7 is a schematic diagram of an energy-taking circuit according to an embodiment of the present invention;

FIG. 8 is a simulation circuit diagram of an energy-taking circuit according to an embodiment of the present invention;

Fig. 9 is a curve diagram of the load output power of the energy harvesting device according to the embodiment of the present invention;

Fig. 10 is a schematic diagram of the installation of an energy harvesting device according to an embodiment of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figure 1 is the flowchart of the present invention, the embodiment of the present invention comprises the following steps:

Step 1: Extract the key parameters of the square wave current of the busbar of the converter valve

The square wave current of the 800kV converter valve thyristor busbar is a square wave current with a constant amplitude of 4500A, a frequency of 50Hz, a duty cycle of 1/3, and a rising edge and falling edge of about 0.8ms. The square wave current will generate a changing magnetic field on the rising and falling edges. According to the law of electromagnetic induction, a closed coil can be used to induce a voltage to obtain electrical energy.

Step 2, get the power characteristics of the energy induction coil, as shown in Figure 2,

Energy harvesting CT is used as the energy harvesting front-end of the energy harvesting power source to obtain energy from the transmission line, and its power transmission characteristics need to be studied. Because the iron core of the energy-harvesting CT is made of cold-rolled silicon steel sheets, the hysteresis loop is narrow and the core loss is very low. In order to reflect the power variation law of the energy-harvesting CT, the resistance of the excitation current

Among them, I _m is the excitation current, I _Fe is the effective value of the resistive component of the excitation current, I ₁ is the effective value of the primary side current, N ₂ is the number of turns of the secondary winding, and I ₂ is the effective value of the secondary side current.

According to the principle of electromagnetic induction, when the primary side input is a sine wave, the effective value of the CT secondary voltage is

Among them, U ₂ is the effective value of the secondary voltage, E ₂ is the effective value of the secondary induced potential, Φ _m is the excitation magnetic flux, f is the system frequency, η is the lamination coefficient of the iron core, and S is the cross-sectional area of the iron core , μ is the relative magnetic permeability of the air-gapped core, and l is the average magnetic path length of the core.

The output power expression of the secondary side of the energy harvesting CT can be obtained as

Where K=2πfμSη/l, K is a parameter reflecting the material and structure of the core, when When the effective load resistance is used, the output power of the energy harvesting CT reaches the maximum value.

The power characteristics of the secondary side of the energy-harvesting CT mainly include the following two points:

①For a given CT, the secondary side power output has a maximum value. The maximum output power is related to the current of the transmission line, the material and size of the core, and has nothing to do with the number of turns of the secondary winding.

② when The power output of the secondary side achieves the maximum value At this time, S, μ, l, η, N ₂ are determined by the frequency f of the line current and the following parameters of CT.

For the current containing harmonics, the power superposition theorem is applied to the multiple harmonic currents respectively, and the maximum power is:

Air-core coil permeability μ = μ ₀

Step 3, core shape analysis

As shown in Figure 3, according to the shape of the busbar of the converter valve, the magnetic cores that can be selected include annular iron cores and U-shaped iron cores. The electric field simulation of these two structures of iron cores is performed with ansys to optimize the magnetic field with air gaps. The shape design of the core reduces the influence of the converter valve busbar on the electric field discharge at the air gap of the magnetic core.

As shown in Figure 4, it is found through simulation that the air gap of the annular iron core is far from the busbar, and the electric field distortion at the air gap is small, so the embodiment of the present invention selects the annular iron core as the magnetic core.

Step 4, core material selection

When selecting a core material, the main considerations are:

The magnetic permeability should be high. When the magnetic field strength in the magnetic core around the busbar is constant, the magnitude of the magnetic induction depends on the magnetic permeability of the material. Under the same square wave current of the busbar, the material with high magnetic permeability will induce a higher voltage value. , so that the volume of the magnetic core can be reduced by reducing the cross-sectional area of the magnetic core.

The smaller the coercive force, the narrower the hysteresis loop, the smaller the coercive force of the core material, the easier the magnetization and demagnetization, the narrower the hysteresis loop, the less heat generated by the hysteresis loss.

The resistivity should be high, and the magnetic core has eddy current loss when it works, and the higher resistivity can reduce the eddy current loss and heat generation.

The saturation magnetic induction intensity should be high to ensure that when the square wave current of the bus bar is large, the magnetic core will not enter the saturation state prematurely, reducing iron loss and heat production while avoiding the generation of peak voltage.

According to the size of the ferromagnetic coercive force, ferromagnetic materials are divided into soft magnetic, hard magnetic and moment magnetic materials. Among them, the coercive force of soft magnetic materials is small, and the hysteresis loop is slender. Compared with other materials, the area surrounded by the hysteresis loop is small, that is, the energy dissipation is less during the magnetization process. In addition, it has It has the characteristics of easy magnetization, easy demagnetization, high saturation magnetic induction, and easy removal of residual magnetism in an alternating magnetic field, so it is suitable for use as a magnetic core material.

Table 1 Magnetic core material characteristic parameter list

As shown in Table 1, the magnetization curve of permalloy has a high squareness ratio, high permeability and extremely low coercive force, but it is expensive, the saturation magnetic induction is low, and the mechanical stress has a significant impact on the magnetic properties. , usually requires a protective case. Microcrystalline alloys have high initial relative magnetic permeability, low price, and are suitable for high-frequency devices. Compared with alloy materials, the saturation magnetic induction of silicon steel sheet is much higher, which can greatly increase the range of the energy harvesting core to adapt to the square wave current of the busbar. The Curie temperature is as high as 740 ° C. This material can fully meet the requirements of the energy harvesting core. In addition, the price of silicon steel sheets is much lower than that of alloy materials, so it has better cost performance.

Considering comprehensively, the magnetic core made of silicon steel sheet material is selected, and various parameters such as the appropriate magnetic core size and the number of coil turns are designed on this basis, and the electric energy that meets the requirements of the back-end device can be induced. The embodiment of the present invention uses an ultra-thin The B23P085 silicon steel sheet.

Step five, core anti-magnetic saturation design

It can be seen from the basic magnetization curve of the magnetic core material that when the bus square wave current is small, the magnetic induction field strength in the magnetic core is small, and as the bus square wave current increases, the magnetic induction intensity gradually increases.

a The dimensions of the energy-taking magnetic core mainly include: inner diameter, outer diameter, and height. Assuming that the magnetic core is a circular ring with a rectangular cross-section, the inner diameter of the magnetic core is a, the outer diameter is b, the height is h, and the cross-sectional area is S, as shown in Figure 5.

Assume that when the magnetic core works in the linear region, the relative magnetic permeability is constant, the magnetic force lines are uniformly distributed on the magnetic core cross-section, and μ _r is the same everywhere on S, and the magnetic permeability is defined by the formula G=μ ₀ μ _r S/L, which can be The permeance of the magnetic core is obtained as:

The magnetic induction intensity when the magnetic core is saturated is B _s , and the magnetic flux in the magnetic core is Φ _m = B _s S, then according to the magnetic circuit Ohm's law, the maximum excitation current when the magnetic core just enters the saturated state is

The maximum excitation current is determined by three parameters: core size, saturation magnetic induction, and core relative permeability. Therefore, the maximum excitation current of the magnetic core can be increased by changing the size of these three parameters, so as to prevent the magnetic core from entering the saturation state prematurely.

When calculating the magnetic core, generally take the cross-sectional area of the magnetic core, the average magnetic circuit length L and the perimeter of the cross-section as L _c

Among them, the average magnetic circuit length mainly affects the consumption of materials, and the perimeter of the cross-sectional area mainly affects the amount of copper used in the coil winding. In order to minimize consumption, the magnetic core size is designed according to the principle that the sum of the average magnetic circuit length and the perimeter of the cross-sectional area is the smallest, that is

L _c +L＝2S/d+(2+π)d+πa (9)

In the case that a is determined, the above formula has a minimum value, and the size of each parameter is calculated as

Therefore, when determining the size of the magnetic core, in the case of meeting the requirements of the output power, the size determined according to the relationship of the above formula can minimize the amount of consumables and achieve the goal of optimizing the magnetic core.

b Magnetic resistance analysis

For ease of installation, two C-shaped or U-shaped magnetic cores can be selected in the design of the magnetic core. When there is an air gap at the core interface, the reluctance of the entire magnetic circuit will change.

If the length of the air gap D is large, the magnetic field lines of the magnetic field in the air gap will expand outward, resulting in edge diffusion. The magnetic lines of force at the edge of the air gap are not straight lines, but protrude outward, which makes the effective area of the air gap larger than the cross-sectional area of the magnetic core. The larger the air gap, the more obvious the edge diffusion phenomenon. Only when the cross-sectional area of the magnetic core is much larger than the air gap (D<0.2d and D<0.2h), the edge diffusion can be ignored, and the magnetic field distribution in the air gap is considered to be the same as that in the magnetic core.

From the definition of reluctance, it can be known that the reluctance of the core is

R ₁ ＝L/μ ₀ μ _r S (11)

Let δ=2D, then the air gap reluctance is

R ₂ =δ/μ ₀ S ₀ (12)

where _S0 is the effective area of the air gap.

When D is small, edge diffusion is not considered, that is, S ₀ =S is considered. When the air gap D is large, the influence of edge diffusion needs to be considered, and the correction coefficient k can be added to the formula, and the formula becomes

R＝δ/μ ₀ (d+kδ)(h+kδ) (13)

In the formula, k=0.307/π, when the cross-sectional area is a square, d=h, the air gap magnetoresistance is

R＝δ/μ ₀ (d+kδ) ² (14)

When the cross-sectional area is circular and D>0.4r, edge diffusion should be considered. The area of the circle is equivalent to a square, that is, d ² = πr ² , put it into the above formula to get

Assuming that the relative magnetic permeability of the entire magnetic core with an air gap is, according to the Ampere loop theorem and the magnetic circuit Ohm's law,

When S ₀ ≈ S, substituting the magnetomotive force into the relational formula of magnetic flux, the relative permeability can be obtained as

Because generally L/δ<<μ _r , the relative permeability of the entire magnetic circuit is greatly reduced, that is, the magnetization corresponding to the magnetic core reaches the saturation magnetic induction is greatly increased.

The relative magnetic permeability of magnetic materials is generally very large (10 ³ ~ 10 ⁴ ), when L/δ=μ _r , R ₁ =R ₂ Although the air gap is very narrow, it increases the reluctance of the entire magnetic circuit double. Under the condition that the magnetomotive force remains unchanged, the magnetic flux in the magnetic core becomes half of the original, that is, the magnetic induction becomes half of the original. Therefore, in the case of the same bus square wave current, the air gap reluctance can be increased by increasing the air gap width, so that the reluctance in the entire magnetic circuit increases and the magnetic flux decreases, that is, the magnetic induction intensity decreases. The introduction of the air-gap reluctance prevents the core from entering the saturation state prematurely, thereby reducing the core loss. Therefore, in a magnetic core with an air gap, the excitation current when the magnetic core enters a saturated state will be greatly increased compared with the original.

In the case of large bus current, by adding an air gap at the interface of the magnetic core, the magnetic core can work in a non-saturated state, thereby avoiding the generation of excessive peak voltage, effectively simplifying and protecting the back-end processing circuit.

In the embodiment of the present invention, the air gap width δ can be obtained according to the designed maximum saturation current.

Step 6, calculation of coil turns

according to As long as the rising edge and falling slope of the mathematical function waveform of the busbar square wave current are consistent, the simulation of the busbar current to the induction coil can be realized.

According to the simulation of the current function, by the formula The secondary induced voltage can be calculated. The waveform of the induced voltage can be replaced by the following mathematical function, identifying M=1, there is

y=4500(cos(x))-cos(5x)-cos(7x)+cos(11x)+cos13(x)-cos(17x)-cos(19x) (21)

In the embodiment of the present invention, according to the waveform drawn by matlab, the maximum value of y is 6.1, that is, the busbar current will induce a peak wave whose amplitude is 6.1 times of the fundamental induced voltage on the secondary side. According to the formula of sinusoidal current induced voltage

Where μ _eq =157, the equivalent rectangular voltage wave is 15V, and N is obtained as 34 turns. The primary side current is much larger than the secondary side, so the induced voltage with load is the same as that with no load.

Load requirements: maximum power P _max = 5W, rated power 2.5W, rated voltage U = 12V, available equivalent resistance R = 28.8Ω, current I = 0.42A, considering margin, load and processing circuit resistance of the embodiment of the present invention Take 20Ω.

The load power is 7.2W>5W, meeting the maximum power requirement of the load.

Step 7, coil inter-turn insulation design

The energy harvesting iron core coil is made of transformer red copper foil, and the insulating material wound on the outer layer is polyester film. 40. The voltage difference between the turns is 0.75V<<5.5kV, so there will be no breakdown between the turns of the energy-taking coil.

Step eight, simulation analysis and performance testing

A, Magnetic core simulation modeling

Use Saber to simulate the circuit of the energy harvesting device. First, model the magnetic core, including the B-H curve of the magnetic core, the shape and size of the magnet, the number of turns of the coil, the stray parameters of the coil, etc., and then test the anti-saturation performance of the magnetic core with a sinusoidal current source. Set the material parameters according to the selected magnetic core, the B-H curve can be imported according to the given curve of the magnetic core, and specify the saturation magnetic induction and saturation magnetic field strength.

The magnetic core shape parameter settings include magnetic circuit length, silicon steel sheet thickness, lamination coefficient, and rectangular cross-section parameters of the magnetic core.

The primary side winding is set to n ₁ =1, the number of turns of the secondary side winding is determined according to the designed output voltage, and the wire diameter of the winding is determined by the effective value of the flowing current. At this point, the modeling of the entire energy-taking core has been completed.

B, core no-load simulation test

Sinusoidal current no-load simulation test

According to the established model, a power frequency sinusoidal current source is added to the primary side of the magnetic core, and the current amplitude is continuously changed, ranging from 100A to 6000A. The secondary side is set to no-load output, and the output voltage amplitude and waveform distortion are observed. When the busbar current is 100A ~ 4500A, the output voltage is a sine wave. When the current value increases to 5000A, the magnetic core has entered a saturated state in a certain period of time, that is, the magnetic flux in the magnetic core changes slowly, and the electromotive force induced at this time It is almost zero; but near the zero-crossing point of the bus square wave current, the magnetic induction in the magnetic core quickly reaches saturation, that is, the magnetic flux in the magnetic core changes rapidly, and the induced electromotive force generated at this time is relatively large. The test results are shown in Figure 6.

Pulse square wave current no-load simulation test

Next, a no-load test is performed on the pulsed square wave current injected into the primary side. The amplitude of the square wave current is 4500A, and the rising and falling edges are set to 0.8ms. It is found by simulation that the no-load voltage amplitude is around 30V, which is consistent with the theoretical calculation results

The overall simulation test of the energy harvesting circuit

As shown in Figure 7, a signal processing module is connected behind the no-load energy harvesting circuit. From left to right, there are a rectifier circuit, a filter capacitor, a voltage stabilizing circuit, and a load equivalent circuit in sequence. Considering the large load power, the filter capacitor must satisfy the law of power conservation, that is, To make the voltage drop during discharge meet the requirement of 10%, the simulated circuit diagram is shown in FIG. 8 , and the embodiment of the present invention selects a capacitor of 10000uF. The regulated input is connected to a 100uF capacitor, and the output is connected to a 10uF capacitor to form a DC/DC output circuit.

Change the load resistance value to simulate the change of the output voltage at the load terminal. When the load resistance is >9Ω, the load voltage is stable at 12V, that is, the maximum output power that the energy harvesting device can output stably is 16W. The relationship between load power and voltage approximately satisfies The power curve of the load output is shown in Figure 9.

When the load equivalent resistance is set to 5Ω, the load terminal voltage is shown in Figure 5-22 (red) waveform. Since the primary side capacitance is not enough to support the energy output of the load, the voltage at both ends has dropped to zero during the discharge phase.

Step nine, performance testing and physical production

According to the no-load output voltage waveform of the energy harvesting device, a bipolar pulse square wave is simulated by an IGBT full-bridge switching circuit. The pulse width and frequency are consistent with the pulse width and frequency of the overall simulation test of the energy harvesting circuit, which is used to test the power supply. Handles the electrical performance of the module.

According to the circuit diagram of the performance test, make the corresponding physical object, and carry out the shell shape design and material selection according to the busbar size and insulation strength

As shown in Figure 10, it is a schematic diagram of the physical installation of the energy harvesting device. The energy harvesting device is installed on the busbar next to the converter valve reactor, and the buckle of the air gap connection of the energy harvesting device is placed on the farthest from the busbar. place, reduce the influence of the busbar on the electric field of the energy-taking iron core to prevent flashover along the surface. The output of the energy harvesting device is connected to the sensor through the power processing module on the left. The entire device is supported and fixed by installing two buckles on the cylindrical surface of the energy harvesting device.

Finally, it is noted that the above preferred embodiments are only used to illustrate the technical solutions of the invention and not limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that it may be possible in form and details. Various changes can be made to it without departing from the scope defined by the claims of the present invention.

Claims (10)

1. the energy taking device design method based on converter valve busbar square wave current, it is characterised in that：This method comprises the following steps：

S1：Extract converter valve busbar square wave current key parameter；

S2：Calculate the power characteristic of the coil of energy taking device；

S3：The core material and shape of energy taking device are selected according to the shape of converter valve busbar, and are analyzed and calculated energy taking device；

S4：The energy taking device of design is emulated, and builds test platform and energy taking device is tested for the property.

2. the energy taking device design method according to claim 1 based on converter valve busbar square wave current, it is characterised in that： Step S2 is specifically comprised the following steps：

S21：Calculate the secondary side voltage effective value of energy taking device；

S22：Calculate the secondary side power characteristic of energy taking device.

3. the energy taking device design method according to claim 1 based on converter valve busbar square wave current, it is characterised in that： Core configuration described in step S3 is U-loop or circular ring shape.

4. the energy taking device design method according to claim 2 or 3 based on converter valve busbar square wave current, feature exist In：Step S3 is specially：

S31：According to the magnetic conductivity of core material, coercivity, resistivity and saturation induction density select core material；

S32：The magnetic resistance and magnetic saturation of magnetic core are analyzed, and determine magnetic core size；

S33：Calculate the coil turn of energy taking device；

S34：Design the coil turn-to-turn insulation of energy taking device.

5. the energy taking device design method according to claim 4 based on converter valve busbar square wave current, it is characterised in that： Step S32 is specially：

S321：Choose toroidal cores, it is assumed that magnetic core is operated in linear region, calculates magnetic core magnetic conductance；

S322：Calculate maximum exciting current when having just enter into saturation state；

S323：Magnetic core size is designed according to the principle of the sum of the average length of magnetic path and sectional area perimeter minimum.

6. the energy taking device design method according to claim 5 based on converter valve busbar square wave current, it is characterised in that： The coil turn of energy taking device meets in step S33：

Wherein, e is induced potential, and n is coil turn, μ_eqFor equivalent permeability, w is the width of iron core internal diameter and outer diameter, and s is iron The thickness of core.

7. the energy taking device design method according to claim 6 based on converter valve busbar square wave current, it is characterised in that： Step S4 is specially：

S41：Magnetic core is modeled according to magnetic core parameter, and magnetic core is accessed into driving source；

S42：It sets driving source to power current, and changes the amplitude for applying power current, magnetic core primary side is carried out unloaded Test, tests and records the output voltage amplitude of magnetic core secondary side；

S43：Power current is replaced with to the square wave current of fixed amplitude, no load test is carried out to magnetic core primary side, tests and remembers Record the output voltage amplitude of magnetic core secondary side；

S44：Magnetic core secondary side access signal processing module composition is taken into energy circuit, and accesses load equivalent circuit；

S45：Apply the resistance value for encouraging and changing load equivalent resistance, test load terminal voltage situation of change, and counted, is obtained Go out conclusion；

S46：Test platform is built, debugging test circuit tests designed energy taking device, obtains and is taken under true environment The performance of energy device.

8. the energy taking device design method according to claim 7 based on converter valve busbar square wave current, it is characterised in that： The signal processing module includes sequentially connected rectification circuit, filter capacitor and regulator circuit, and the rectification circuit is connected to The magnetic core secondary side, the regulator circuit are connected to the load equivalent circuit.

9. the taking based on converter valve busbar square wave current made according to any design methods of claim 1-8 can fill It sets, it is characterised in that：The magnetic core of the energy taking device is in be divided into primary side magnetic core and secondary side magnetic core, and divide to open annular It is not wound with first siding ring and second siding ring, the magnetic core is made of silicon steel sheet, and gas is both provided in two openings Feeler and by Spring Card spring pressing, the energy taking device is used to extract line parameter circuit value in high-tension line.

10. the energy taking device according to claim 9 based on converter valve busbar square wave current, it is characterised in that：Described The coil turn-to-turn insulation of first siding ring and second siding ring is formed using polyester film coiling.