KR101202443B1 - Simulated Resistor Load Control Method for Acquiring Energy Generated from the Pressure Exerted by Passing Vehicles - Google Patents

Abstract

The present invention relates to a method for acquiring vehicle load generation energy in a power converter comprising a generator for generating energy by a load of a vehicle passing on a load plate, and a capacitor for storing energy generated from the generator. Measuring a vehicle speed of the vehicle passing through the vehicle; calculating a simulated load resistance value at which energy generated at the measured vehicle speed is drawn to the maximum; and a virtual load resistance having the calculated simulated load resistance value is applied to the generator. When connected, calculating a charging current delivered to the capacitor, and controlling the calculated charging current to be input to the capacitor.

Description

Simulated Resistor Load Control Method for Acquiring Energy Generated from the Pressure Exerted by Passing Vehicles}

The present invention relates to an apparatus and method for obtaining renewable energy, and more particularly, to an apparatus and method for acquiring vehicle load generation energy capable of capturing and storing kinetic energy of a vehicle to be forcibly consumed through a braking device.

As the green growth industry has been spotlighted as the future industry all over the world, the utilization of eco-friendly energy is more important than ever, and interest in this has been amplified, and academic research is being actively promoted.

Traditional fossil fuels are energy that can be extinguished once used, whereas renewable energy is an energy that can be used continuously because its energy sources are constantly generated. Renewable energy refers to energy such as solar, sunlight, biomass, wind, hydro, geothermal, ocean, and waste, and means clean energy with significantly reduced pollution generation.

Vehicle load generation, which is generated using vehicle loads on the road, meets both renewable energy requirements and clean energy requirements that do not emit pollutants, a requirement for renewable energy. Therefore, an eco-friendly power generation system using the load of the vehicle is emerging around developed countries. In Korea, there is a movement to promote the development of this system centering on venture companies.

In foreign countries, these power generation devices are installed in highway entrances, toll gates, schools, bus stops, parking facilities, and underground parking slopes of buildings, and several companies have been introduced on the Internet. As a result, related companies interested in renewable energy and eco-friendly energy are closely watching the industry's development. Considering that there are over 700 million vehicles worldwide, the new vehicle load generation system has the potential to bring significant waves to the industry and technology.

The vehicle load generation system is an area that is attracting much attention because it is a concept that is emerging in the flow of new industries such as renewable energy, green growth, and eco-friendly energy, but there are still few prior arts and related data. In other words, disclosure is extremely limited for technologies developed by the industry.

For this reason, there is an urgent need for research on a load generation system using a vehicle, and it is time for an integrated study of mechanical hardware, electronic hardware, and core software and management software for operating the hardware.

In addition, since the energy generated through the load generating device of the vehicle is pulsed energy occurring within a short time, the generated energy cannot be efficiently used without drawing it out in a timely manner. The energy generated through the load generator is greatly changed in the drawing and storage efficiency according to the speed, mass, intrinsic constant of the generator, electrical load conditions, and the like. Therefore, it is necessary to study the method of optimizing the generation and storage of energy through the whole process of energy flow and managing the control variables dynamically in order to optimize the extraction and storage efficiency.

Accordingly, the present invention provides a method for obtaining energy generated from vehicle load generation.

The present invention also provides a method of dynamically managing control variables in vehicle load generation to obtain maximum energy according to load generation.

The present invention provides a method for acquiring vehicle load generation energy in a power converter comprising a generator for generating energy by a load of a vehicle passing on a load plate, and a capacitor for storing energy generated from the generator. Measuring a vehicle speed of the vehicle passing through the vehicle; calculating a simulated load resistance value at which energy generated at the measured vehicle speed is drawn to the maximum; and a virtual load resistance having the calculated simulated load resistance value is generated by the generator. When connected to, characterized in that it comprises the step of calculating the charging current delivered to the capacitor, and controlling the calculated charging current is input to the capacitor.

The present invention connects a virtual load resistor to a power converter, retrieves a virtual load resistance value capable of extracting the maximum energy, and then stores current such as a capacitor located at the rear of the power converter to realize the virtual load resistance. There is an advantage that it is possible to efficiently obtain the energy by the vehicle load generation to control the precisely.

함수를 나타낸 도면이다.
도 10은 부하저항에 따른 완주 시간 그래프를 도시한 도면이다.
도 11은 부하저항 및 차속에 따른 발생 에너지를 나타낸 도면이다.
도 12는 부하저항에 따른 발생 에너지를 나타낸 도면이다.
도 13은 부하저항 및 차속에 따른 제한된 발생에너지를 나타낸 도면이다.
도 14는 차속과 부하 저항에 따른 최대 발생 에너지를 나타낸 도면이다.
도 15는 차속에 따른 최대 발생 에너지 및 최대 에너지를 발생시키는 부하 저항값을 나타낸 도면이다.
도 16은

=10 일 경우, 고유정수 K에 따른 최대 에너지 인출을 나타낸 도면이다.
도 17은

=8 일 경우, 고유정수 K에 따른 최대 에너지 인출을 나타낸 도면이다.
도 18은 본 발명의 바람직한 실시 예에 따라, vco=0 V일 경우의 시스템 변수에 따른 그래프를 나타낸 도면이다.
도 19는 본 발명의 바람직한 실시 예에 따라, vco=100 V 일 경우의 시스템 변수에 따른 그래프를 나타낸 도면이다.
도 20은 본 발명의 바람직한 실시 예에 따라, vco=0 V 일 경우 에너지 발생량과 저장량을 도시한 도면이다.
도 21은 본 발명의 바람직한 실시 예에 따라, vco=100 V일 경우 에너지 발생량과 저장량을 도시한 도면이다.
도 22는 본 발명의 바람직한 실시 예에 따라 차속에 따른 저장 에너지를 도시한 도면이다.1 is a diagram illustrating an example in which a vehicle load plate is installed.
2 is a view showing a simplified configuration of the load generator.
3 is a view showing a descending speed of the load plate.
4 is a view showing a descending acceleration of the load plate.
5 is a view showing the relationship between the magnitude of the load and the falling speed.
6 is a circuit diagram illustrating a vehicle load generation energy obtaining apparatus using simulation resistance control according to an exemplary embodiment of the present invention.
7 is a flowchart illustrating a method for obtaining vehicle load generation energy through simulation resistance control according to an exemplary embodiment of the present invention.
8 illustrates a Lambert W function.
9 is

A diagram showing a function.
10 is a graph illustrating a completion time graph according to load resistance.
11 is a view showing generated energy according to load resistance and vehicle speed.
12 is a view showing the generated energy according to the load resistance.
FIG. 13 is a view illustrating limited generated energy according to load resistance and vehicle speed. FIG.
14 is a view showing the maximum generated energy according to the vehicle speed and the load resistance.
15 is a diagram illustrating a maximum generated energy and a load resistance value for generating the maximum energy according to the vehicle speed.
16 is a cross-

In the case of = 10, the drawing shows the maximum energy withdrawal according to the high constant K.
17 is

When = 8, the figure shows the maximum energy withdrawal according to the high constant K.
18 is a diagram illustrating a graph according to a system variable when vco = 0 V according to a preferred embodiment of the present invention.
19 is a diagram illustrating a graph according to a system variable when vco = 100 V according to a preferred embodiment of the present invention.
20 is a view showing an energy generation amount and a storage amount when vco = 0 V according to a preferred embodiment of the present invention.
FIG. 21 is a diagram illustrating an energy generation amount and a storage amount when vco = 100 V according to a preferred embodiment of the present invention.
FIG. 22 is a diagram illustrating stored energy according to a vehicle speed according to an exemplary embodiment of the present invention. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the embodiments of the present invention may unnecessarily obscure the gist of the present invention.

Prior to describing the present invention, terms used throughout the specification may be sufficiently modified according to the intention, customs, etc. of the user or operator, and the definition of the terms should be made based on the contents throughout the specification of the present invention. will be.

The present invention provides a method for obtaining maximum energy through vehicle load generation in response to a change in vehicle speed or load.

To this end, the present invention connects a simulated load resistor to a power converter, searches for a simulated load resistance value capable of extracting the maximum energy, and then uses a capacitor located at the rear of the power converter to realize the virtual load resistance. We present a method for acquiring vehicle load generation energy through simulation resistance control to precisely control the current of the same storage unit.

First, the operating principle of vehicle load generation will be described to help understanding of the present invention.

In order to decelerate or stop a vehicle traveling at a constant speed, it must consume its kinetic energy. That is, the vehicle applies braking to reduce the kinetic energy at a stop line, a toll gate, or a steep downhill at a range, and the kinetic energy is consumed as thermal energy by friction with the road surface during braking.

Therefore, an energy absorbing load plate such as an overspeed bump having a predetermined length and a constant height in a traveling direction is installed in a section requiring braking as shown in FIG. 1 for vehicle load generation.

FIG. 2 shows an example of a simplified structure of a load generating device installed under the load plate as shown in FIG. 1.

As shown in Figure 2, the load plate is supported by the structure of the non-linear spring, not too high to maintain a proper ride comfort, and must have a structure that is restored to its original state after the vehicle presses through the load plate. In the present invention, it is assumed that the amount of energy used to restore the load plate to its original position is assumed to be negligibly small compared to the amount of energy generated by the load of the vehicle.

As the vehicle approaches the load plate, its vertical position varies by the height of the load plate, where a portion of the kinetic energy of the vehicle is converted into potential energy. This potential energy is a source of energy for driving the lower power generation device as the load plate falls under the weight of the vehicle. However, since the vehicle stays on the load plate for a short time, the electric energy generated in the vehicle load generator is in the form of energy with a short pulse width.

When the rotary generator is represented by Equation 1, it is very convenient to interpret the linear DC generator model.

When the vehicle is on the load plate, the load plate moves in a straight line and rotates the generator through the conversion gear on the shaft of the generator. This structure can be thought of as a generator with a group of conductors that linearly move in a constant magnetic field when viewed from a load plate. The magnetic field of the rotating machine changes according to the rotation angle, but if the effective value of the magnetic flux density is used based on one cycle, it can be interpreted as the time-invariant magnetic flux density in the linear DC generator. In addition, the magnetic flux density, the length of the conductive wire, the gear ratio, and the like can be expressed as K by tying up a high integer.

는

를 상수로 하여 하중판의 하강 속도에 비례하며, 발전기를 구동시키는 힘에 반대 방향으로 생기는 유도된 힘

역시

를 상수로 하여 부하전류

에 비례한다. 즉, 외부동력에 의하여 발생한 기전력은 내부 회로로 전력을 공급하고 이 때 돌아오는 부하 전류로 말미암아 플레밍의 왼손법칙에 의하여 외부동력에 반대되는 방향으로 유도된 힘이 작용한다. 외부 동작에 대항하는 힘의 발생으로 외부 동력으로 움직이던 자속을 끊는 도체의 속도는 제한을 받게 되고, 속도가 감소하면서 도체에 발생하는 기전력이 감소하며 기전력의 감소는 부하전류의 감속으로 이어져 전형적인 부궤환 제어가 이루어진다. As can be seen from Equations 1 and 2, the electromotive force of the linear DC generator

The

Induced force generated in the opposite direction to the force driving the generator, proportional to the descending speed of the load plate

Also

Load current with constant

Proportional to That is, the electromotive force generated by the external power supplies power to the internal circuit, and the force induced in the direction opposite to the external power by the Fleming's left-hand law acts due to the return current. The speed of a conductor that breaks the magnetic flux that was moved by external power is limited by the generation of force against external movement, and as the speed decreases, the electromotive force generated in the conductor decreases. Feedback control is made.

로 나타난다. 이 힘에 의하여 발전기가 시동하기 시작하면 무부하 상태에서는 저항받는 힘이 없으므로 이론적으로 중력 가속도

에 가까운 속도로 증가하지만 일단 부하가 걸리게 되면 부하전류에 비례상수

를 곱한

에 해당하는 유도된 힘이 반발력으로 나타나 속도의 증가가 둔화된다. 이를 수학식으로 나타내면 하기의 <수학식 3>과 같고, 이를 정리하면 <수학식 4>와 같다.The vehicle on the load plate begins to descend by gravity. The force of gravity presses the shaft of the generator through the load plate and the gear of the generator. The force the vehicle presses

Appears. When the generator starts to be started by this force, there is no force to resist under no load, so theoretically the acceleration of gravity

Increases at a speed close to, but once the load is applied, it is proportional to the load current.

Multiplied by

The induced force corresponding to this is shown as a repulsive force, and the increase in speed is slowed down. This is expressed as Equation 3 below, and summed up as Equation 4 below.

은 차량의 질량이고,

는 차량이 하강하는 속도이고,

는 부하전류에 의한 반발력이고,

는 중력 가속도를 의미한다.In <Equation 3> and <Equation 4>

Is the mass of the vehicle,

Is the speed at which the vehicle descends,

Is the repulsive force due to the load current,

Means gravitational acceleration.

The current flowing through the vehicle load generating apparatus changes depending on the magnitude of the load. The adjustment of the load current can be made artificially, such as external operation, but the current change of the load affects the speed of descent and changes the magnitude of the electromotive force, making the system quantitatively difficult to analyze. First, the basic operation principle of the generator through the resistive load, which is passive rather than the active load, is examined.

Resistive loads are defined as a linear relationship between current and voltage, which is convenient for understanding the type of operation and provides basic knowledge for future active adjustments. This is a necessary step in analyzing the type of operation of a generator.

가 발생할 때, 부하전류는 발전기의 내부저항

과 외부의 저항성 부하

을 통하여 흐르므로 부하전류는 <수학식 5>와 같다. Electromotive force

Load current, the internal resistance of the generator

Resistive loads

Since it flows through, the load current is as shown in Equation 5.

이다. Substituting <Equation 5> into <Equation 4>, the falling speed can be obtained as shown in <Equation 6>. At this time, the initial descent speed is that the vehicle starts to fall at a certain height

to be.

는 다음의 <수학식 7>와 같이 표현된다.Solution to Equation 6

Is expressed as Equation 7 below.

On the other hand, K is a value representing the characteristics of the generator has a value unique to the generator. As shown in Equation 7, when the load resistance is constant, the descending speed of the vehicle appears in the form of an exponential function. Depending on the R and K values, the descending speed is directly affected and also shows a large difference in the amount of energy drawn according to the present invention. However, in the case of K value, if it exceeds a certain value, it does not have a big influence on energy withdrawal.

Since the falling speed and the electromotive force are directly proportional, it is very important to observe the change in the falling speed, and it is sometimes necessary to artificially adjust the falling speed for power drawing and maximum energy drawing. Since the descending speed is one of the most important parameters that are directly related to the vehicle's approach speed and ultimately withdrawal of energy, the withdrawal and storage performance of energy is greatly affected by how the parameter is controlled in the future. As time goes by, the speed does not increase much and ultimately the constant speed motion results in a constant voltage and a similar current.

3 shows the relationship between time and load plate descent speed when a resistive load is connected to a linear direct current generator.

The falling acceleration of the load plate in the resistive load is expressed as Equation (8), and FIG. 2 shows a graph of the acceleration of falling of the load plate with time.

Looking at the acceleration characteristics of the load plate in Figure 4 it can be seen that gradually decreases with time and converges to the zero point. Since the acceleration value is always positive, the drop speed is a monotonically increasing function. In other words, in the fixed resistive load, the drop speed and the electromotive force are continuously increased without decreasing. This characteristic fits well with the typical environment in which supercapacitors or batteries are used for energy storage and open the way for easier energy storage. However, the electromotive force continues to increase at all fixed resistive loads, resulting in the loss of kinetic energy at the end of the drop and upon reaching or passing through the ground, making it difficult to capture maximum energy.

5 shows the descending speed of the load plate according to the size of the load. Although the advantages and disadvantages coexist in energy collection through such a resistive load, energy can be efficiently drawn out by the method of the present invention.

Therefore, it is important to examine in detail how the descent speed of the vehicle will vary with different resistive load values. It can be predicted that the speed will be faster if the load is small, but it is necessary to know in advance how much the difference is.

Although there is some resistance of the spring applied to the load plate and rotor inertia and friction of the power generator even under no load, it is relatively low as mentioned above. It can be seen that the time to reach a shorter time and the final speed also become smaller.

Next, a circuit configuration of a power converter for obtaining vehicle load generation energy using simulation resistance control according to an exemplary embodiment of the present invention will be described with reference to FIG. 6.

The power converter can be configured in one or multiple stages, and can perform voltage control and current control simultaneously. In particular, the power converter with the supercapacitor connected to the final stage should be able to control the current freely.

The power converter has a non-linear conversion efficiency and a constant input voltage threshold with respect to the input power, but this factor will not be considered in the present invention. Nevertheless, the present invention does not significantly affect the gist of the present invention, and in practical applications, it is possible to solve a problem that may occur due to omitted circuit elements by setting boundary conditions thereto.

In addition, the present invention relates to the energy acquisition according to the load generation of the vehicle, but if the energy extraction process of the present invention is partially changed, it can be applied to similar load generation other than the vehicle.

In addition, it is an object of the present invention to simulate the optimal load conditions to withdraw the generated energy to the maximum, to adjust the load in real time to adjust the input energy to the power source while aiming for economic operation with maximum efficiency This is different from the usual method.

In the case of load generation, the maximum energy that can be generated when a vehicle traverses a load plate having a certain height and a certain length is already determined. Therefore, a method for obtaining the maximum energy for the generated energy must be developed in a short time. do.

In addition, the present invention requires two prior information to be obtained dynamically for its application. Detecting vehicle speed and collecting weight information of the vehicle, but the detailed description thereof will be omitted here because the method of obtaining the information is out of the gist of the present invention.

Referring to FIG. 6, the power converter includes a power generator 110, a power limiter 120 for protecting the power generator 110, a voltage controller 130, a current controller 140, and a supercapacitor 150. ), And the control unit 160.

을 가진다. 수퍼커패시터(150)는 등가직렬저항(ESR)

를 가지며,

는 ESR 전압강하를 포함하지 않는 순수한 커패시터에 저장된 전압을 의미한다. The power generation unit 110 is a linear direct current machine and internal resistance

. Supercapacitor 150 has an equivalent series resistance (ESR).

Lt; / RTI &gt;

Denotes the voltage stored in a pure capacitor that does not contain an ESR drop.

In addition, in most cases of vehicle load power generation, energy is generated by generating power by stepping on a load plate as the vehicle passes by, and most of the energy generated by the power generation device appears in various types of pulsed voltage waveforms in a very short time within 0.5 seconds. In this case, therefore, it is necessary to charge a large amount of instantaneous pulsed energy in a short time. In order to efficiently store energy generated in a relatively short time, it is possible to meet such a demand by using a supercapacitor having the characteristics of a general capacitor instead of a storage device using a chemical reaction such as a battery.

The current controller 140 of the final stage is a device for controlling the current input to the supercapacitor 150 has a fast negative feedback control and response characteristics.

The simulated resistor R is not actually connected and is only a target value for control. Here, R is applied to the method of the present invention as if the load is actually connected. The power of the input and output sides of the voltage controller 130 and the current controller 140 is the same and is considered an ideal converter.

The controller 160 finds the withdrawal point of the resistive load capable of drawing the maximum energy through the simulation resistance control, and then controls the current controller 140 to control the current controller 140 for the effect that the simulation resistor R is actually connected. 150 to control the current input.

The operation of the control unit 160 will be described in more detail through a method of acquiring vehicle load generation energy through mock resistance control which will be described later.

7 is a flowchart illustrating a method for obtaining vehicle load generation energy through simulation resistance control according to an exemplary embodiment of the present invention.

In accordance with a preferred embodiment of the present invention, a method for acquiring vehicle load generation energy through simulation resistance control includes calculating a simulation resistance value capable of extracting maximum energy in real time corresponding to a vehicle speed, and calculating the simulation resistance value in real time. Corresponding to the process of calculating the charging current to be input to the supercapacitor 150 correspondingly.

Referring to FIG. 7, the controller measures the vehicle speed of the vehicle passing through the load plate in step 210. In operation 220, a simulated resistance value R for extracting maximum energy from the measured vehicle speed is determined.

Next, an algorithm for determining a simulated resistance value R that can extract the maximum energy according to the vehicle speed will be described in detail.

First, let's look at the completion time. Completion time refers to the time it takes for the vehicle to reach the ground from the load plate, and as described above, the time it takes to complete to the ground is easy because both speed and acceleration are not linear to the time variable in the vehicle descent speed. Can't calculate In addition, depending on the load, the vehicle may complete to the ground, or the vehicle may pass quickly through the load plate before it reaches the ground. It should be chosen as the fall time.

First, consider the case where the completion time is less than the passage time, that is, when the vehicle touches the ground while the vehicle is on the load plate, and then the case where the passage time is less than the completion time, that is, the load plate does not touch the ground. .

On the other hand, power and time are needed to calculate the total energy delivered to the load. Power is relatively simple, but time is calculated in several processes. First, you need to calculate the distance using your car's descent speed and use that distance to invert the time it takes to reach the ground completely.

Determining if you can complete the road depends on the load and the speed of the vehicle. In general, it is possible to complete the run when the electric load connected to the power generation device is small and the vehicle's ground moving speed is low.

Completion distance is calculated as in <Equation 9> from the falling speed of <Equation 7>, and the completion time is calculated inversely from <Equation 9>.

는 특정부하에서 지면까지 완주하는 데까지 걸리는 시간을 의미한다. 완주시간

은 발전장치의 고유정수 K와 발전장치에 연결된 전기 부하저항, 발전장치의 내부저항 등에 영향을 받게 된다. 부하 저항값이 작으면 부하가 많이 걸리는 형태이므로 다음의 <수학식 10>에서 알 수 있는 바와 같이 완주하여 지면에 닿는 시간이 길어진다. 완주시간

를 구하면 <수학식 10>과 같다. In Equation (9), h means the height of the load plate, and in general, it may be determined at 35-50 mm in consideration of the driver's safety and riding comfort. Completion time

Means the time it takes to reach the ground from the specified load. Completion time

Is affected by the intrinsic constant K of the generator, the electrical load resistance connected to the generator, and the internal resistance of the generator. If the load resistance value is small, it takes a lot of load, and as shown in Equation 10 below, the time required to reach the ground becomes long. Completion time

The equation is given by Equation 10.

는 Lambert W 함수를 의미한다. 도 8 및 도 9는 Lambert W 함수에 대한 도면을 도시하고 있다.here,

Means Lambert W function. 8 and 9 show diagrams for the Lambert W function.

는 후술할 통과 시간과 더불어 본 발명에서 매우 중요하게 다루는 변수이다. 하강하는 차량으로부터 에너지를 인출할 때 완주 시간은 최대에너지를 제한하는 요소가 된다. The finish time mentioned above

In addition to the passing time to be described later is a variable that is very important in the present invention. Completion time is the limiting factor for maximum energy when drawing energy from a descending vehicle.

Next, let's take a look at the transit time.

The transit time of the load plate is one of the most important variables in the overall energy extraction process. If the pass time is relatively long, it can capture a lot of energy, but when the pass time is short, the result is negligible no matter which withdrawal algorithm is used. We will then verify that withdrawal of energy is meaningful within the vehicle speed. The passing time of the vehicle can be obtained as shown in Equation 12.

는 차량이 주행하는 방향으로 하중판의 길이(m)이며,

는 차량의 수평이동 속도로 단위는 km/h이다.In Equation 12

Is the length of the load plate (m) in the direction in which the vehicle is traveling,

Is the horizontal movement speed of the vehicle, measured in km / h.

Next, the generated energy calculation will be described.

Using the time information calculated so far, we want to find the energy actually supplied to the load. First, the load current must be obtained. This value can be calculated by Equation 13.

The instantaneous power delivered to the load during the short fall time of the vehicle can be obtained as shown in Equation 14 below.

라 하면 에너지는 <수학식 15>에 의해 산출될 수 있다. The extracted energy is obtained using the instantaneous power calculated by Equation (14). What's important is the time interval

Then, energy can be calculated by Equation 15.

는 전술한 바와 같이 두 가지 경우로 나누어진다. 통과 시간

가 완주시간

보다 작은 경우와 큰 경우이다. 통과 시간이 완주시간보다 짧을 경우에는

=

가 되고, 부하에 전달되는 에너지 발생량은 완주시간에 상관없이 <수학식 15>를 이용하여 차량의 속도

와 부하저항 R의 함수로서 <수학식 16>과 같이 나타난다. Descent time

Is divided into two cases as described above. Transit time

Completion time

Smaller and larger. If the transit time is shorter than the finish time,

=

The amount of energy delivered to the load is determined using the equation (15) regardless of the completion time.

And as a function of load resistance, R,

FIG. 11 represents the energy delivered to the load when the transit time of the vehicle is shorter than the completion time, ie when the vehicle is traveling at a relatively high speed. As shown in FIG. 9, energy is expressed as a function of vehicle speed and load resistance.

On the other hand, if the transit time of the vehicle is longer than the completion time, the load plate falls down to the ground by touching the ground or through the ground, but when descending to the ground, the vehicle has to use energy again to get to the ground, so eventually The time to reach or cross the ground is seen as the end of the descent. In this case, the energy delivered to the load is independent of the speed of the vehicle and only appears as a function of the load resistance R. Since the energy transfer is limited by reaching the ground, the load energy is expressed as in Equation 17.

12 is a maximum energy transfer curve that can be seen when the vehicle horizontal passage time is longer than the completion time. Regardless of the speed of the vehicle, it appears only as a function of the load resistance R.

13 shows the energy generated according to the relationship between the horizontal passage time and the completion time of the vehicle.

The load resistance value that generates the maximum energy changes according to the vehicle speed. When the vehicle speed is relatively high, the vehicle cannot reach the ground, so it is separated from the ELMT line, which is the energy limiting line when it reaches the ground. In this case, it can be seen that the maximum energy withdrawal point is found in the direction in which the load resistance value increases as the vehicle speed decreases.

However, when the horizontal transverse speed of the vehicle is further reduced and the load plate comes into contact with the ground, the ELMT line is restricted and no further energy increase occurs.

Therefore, the gist of the present invention is to find the simulated load resistance value at which the generated energy is maximum depending on the vehicle speed.

It can be seen from FIG. 13 that the simulated load resistance value at which energy is maximized according to the vehicle speed can be clearly retrieved.

와 부하저항 R의 함수로 나타나는 에너지 인출량을 삼차원적인 그래프로 보여준다. 차량이 최대 에너지를 낼 수 있는 지점을 지나 저속으로 운행할 경우에는 모의 부하 저항값을 에너지를 최대로 인출할 수 있는 값에 고정하여 차량속도에 무관하게 제어하는 것이 필요하며 이는 본 발명에서 제시하는 중요한 요소 중의 하나이다.14 is vehicle speed

The three-dimensional graph shows the energy draw as a function of and load resistance R. When the vehicle runs at a low speed past a point that can produce the maximum energy, it is necessary to fix the simulated load resistance value to a value capable of extracting the maximum energy and to control the vehicle speed regardless of the speed of the vehicle. It is one of the important factors.

Although the maximum energy withdrawal point according to the vehicle speed is shown in the graphs in FIGS. 13 and 14, a more detailed process is required to calculate an accurate value.

As shown in FIG. 13, when the passage time is greater than the completion time, the point where the energy curve for each vehicle speed and the ELMT curve meet is the maximum energy point, and the simulated load resistance value of the point may be calculated as the maximum energy draw point. However, if the transit time is less than the completion time, the derivative of the energy (E) function must be found after the derivative of the energy (E) to find the maximum energy draw point. Equation (18) shows the result of differentiating the energy (E) function (Equation 16) with respect to the simulated load resistance R.

에 대하여 DE=0가 되는 지점을 찾으면 최대 에너지를 인출할 수 있는 모의 부하 저항값을 찾을 수 있다. <수학식 18>로부터 최대에너지 인출을 할 수 있는 모의부하저항을 구하여 도 15에 나타내었다. Each vehicle speed

By finding the point where DE = 0, we find a simulated load resistance that can draw the maximum energy. The simulated load resistance capable of extracting the maximum energy from Equation (18) was obtained and shown in FIG. 15.

The upper part of FIG. 15 shows the maximum energy that can be drawn with respect to the vehicle speed, and the lower part shows the load resistance value that can extract the maximum energy according to the vehicle speed. In the lower load resistance curve, the right side of the load resistance peak value shows the case where the transit time is shorter than the finish time, and the left side shows the case where the load plate touches the ground because the transit time is longer than the finish time.

Referring back to FIG. 7, the controller determines a simulated resistance value capable of extracting the maximum energy according to the vehicle speed using FIG. 15 calculated through the algorithm as described above in operation 220.

On the other hand, the influence of the intrinsic constant K of the power generation unit will be described. In finding the maximum energy draw point, it can be said that it is meaningful to find out how K, the intrinsic constant of the power generation device, has an effect. Keep the vehicle speed constant and change the load resistors R and K to see how they affect energy extraction. Equation 17 is used to evaluate the influence of the high constant K, and FIG. 16 shows the result.

As shown in FIG. 16, the high constant K of the power generation device does not affect the maximum energy extraction unless it has an excessively small value in energy extraction.

After changing the speed of the vehicle as shown in FIG. 17, even if the calculation is attempted, the result does not change. That is, it was confirmed that there is no correlation between the value of K and the maximum energy withdrawal. Therefore, the present invention implies that it can be generally applied without depending on the characteristic value of the generator itself.

Up to now, the technique of properly extracting the energy generated by the load plate by controlling the simulated load resistance has been presented.

Referring to FIG. 7 again, in step 230, the fall time is calculated using the vehicle speed measured in step 210, which is a process of calculating the completion time and the passage time as described above. Then, by comparing the completion time and the pass time calculated in step 240, and set as a lower value as in the steps 250 and 260.

Next, steps 270 to 290 of FIG. 7 are to store the extracted energy in the supercapacitor through the power converter, and an algorithm thereof will be described in detail.

However, the actual circuit implementation should take into account the proper conversion efficiency, but in the present invention, the input and output efficiency of the power converter is set to 1 for easy deployment of the algorithm. By properly controlling the current charged to the supercapacitor in the power converter, the input side of the power converter appears as if it is a resistive load so that the maximum energy extraction mechanism by the simulated resistor can be applied as it is.

The current flowing through the generator is expressed by Equation 20, and the instantaneous power input to the power converter is expressed by Equation 21.

The output power of the power converter is the sum of the power consumed in the equivalent series resistance (ESR) of the supercapacitor and the power stored in the capacitor itself.

Since the input / output efficiency is 1, it becomes. If it is necessary to calculate the value for the system variable in consideration of the conversion efficiency, the efficiency of the power converter should be multiplied by. Rewriting Equation 20 into the power delivered to the load resistance is shown in Equation 23. This corresponds to step 270 of FIG. 7.

에 대하여 다시 정리하면, 하기의 <수학식 24>와 같이 나타낼 수 있다.Equation 23 above

Re-arranged with respect to Equation 24, Equation 24 may be used.

인 경우에만 관심이 있으므로,<수학식 24>를 <수학식 25>과 같이 표현할 수 있다. Conditions in which the energy stored in the capacitors continues to increase without decreasing, i.e.

Since it is only interested in, Equation 24 may be expressed as Equation 25.

, 단계오차가

수준임을 의미한다.Equation 25 is a nonlinear first-order differential equation that does not allow an exact solution, so we use a numerical method to solve the problem. In the present invention, the 4th order Runge-Kutta method, which is known to have high accuracy in numerical analysis of differential equations, can be used. Fourth order means that the total cumulative error is

, Step error

Means level.

를 구하는데, 충전전류

는 <수학식 26>에 의해 산출된다. 이는 도 7의 290 단계에 해당한다.Charging current, the final control current after solving by Runge_Kutta method

To obtain the charging current

Is calculated by Equation 26. This corresponds to step 290 of FIG. 7.

18 shows the results of the analysis using the system constants of Table 1 below. The method of the present invention is not limited to the length of the load plate and the installation height, but for convenience of explanation, the load plate and the specifications of the vehicle are set in consideration of the speed bumps used in the general road as shown in Table 1. This is merely an example, and the present invention is not limited thereto.

As shown in FIG. 18, the input voltage and current continue to increase and converge to a constant value. Thus, the rate of descent on the load plate converges to a constant value and appears to no longer increase. In addition, as the input power converges to a constant value, the charging voltage increases as long as energy is stored, and thus the charging current decreases.

19 shows waveforms when the initial voltage of the supercapacitor is 100V. It can be seen that the charging current is significantly reduced than when the initial voltage is small. When the initial voltage is maintained at a high level, the energy transfer efficiency is improved and the charging current, which is the final control target, is also reduced, so that stable control with less control width can be achieved.

Next, the storage energy calculation process will be described.

Since the final charging voltage and charging current are obtained, the energy stored in the supercapacitor is calculated as shown in Equation 27. As shown in Equation 27, the finally stored energy is greatly influenced by the equivalent series resistance value of the capacitor.

The energy generated by the generator and the energy delivered to the simulated resistor are obtained by multiplying the electromotive force and the load voltage by the load current and integrating it over time.

In the present invention, since the initial voltage of the supercapacitor is an important parameter for maximum energy transfer, the energy extraction states are verified at voltage initial values 0 V and 100 V and are shown in FIGS. 20 and 21.

Referring to FIG. 20, when the initial voltage of the supercapacitor is 0 V, the storage amount is significantly reduced compared to the amount of energy generated. However, referring to FIG. 21, it can be seen that the energy storage amount calculated in the state where the voltage initial value is raised to 100 V is greatly increased. Therefore, in the storage and transfer of energy, it is advantageous for optimal energy storage to operate the supercapacitor at a constant level as much as possible when retransmitting the energy of the supercapacitor to a large capacity external battery or other load.

22 finally shows the energy state stored in the supercapacitor. It shows the storage state of the energy according to the initial value of the capacitor and the vehicle speed that dynamically changes under the optimized load condition. Although the energy storage varies depending on the voltage initial value of the capacitor, the simulated resistance control method shows excellent performance under relatively low voltage initial value of the capacitor.

Claims (3)

In the method for acquiring vehicle load generation energy in a power converter comprising a generator for generating energy by the load of the vehicle passing over the load plate, and a capacitor for storing the energy generated from the generator,
Measuring a vehicle speed of the vehicle passing through the load plate;
Calculating a simulated load resistance value at which energy generated at the measured vehicle speed is drawn to the maximum;
Calculating a charging current delivered to the capacitor when the virtual load resistor having the calculated simulated load resistance is connected to the generator;
And controlling the calculated charging current to be input to the capacitor. The method of claim 1, wherein calculating the simulated load resistance value
Simulated load resistance control, characterized by calculating the simulated load resistance value maximizing the energy calculated by Equation (29) below using instantaneous power delivered to the load during the fall time at the load plate of the vehicle. Method of acquiring vehicle power generation energy through
<Equation 29>

here,

Is the fall time of the load plate, m is the mass of the vehicle, g is the acceleration of gravity, K is the high constant of the generator, r is the generator internal resistance, and R is the simulated load resistance.
The method of claim 1, wherein calculating the charging current
Calculating load power according to the calculated virtual resistance value;
Calculating a charging voltage using the calculated load power;
And calculating a charging current from the calculated charging voltage.

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