JP2009232516A - Charging device for small wind generation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve charging control with a simple structure, which is excellent in stability, power conversion efficiency from wind power to electric power and a maximum power point tracking characteristic. <P>SOLUTION: A charging device 4 comprises: a control target current value generating means 13 for computing and outputting the control target current value of the output current of a wind generator 2, wherein the output power of the wind generator 2 in the present wind velocity is maximized, from the present output state of the wind generator 2, based on the output characteristics obtained by measuring in advance the relation among the output current, output voltage and rotation speed of the wind generator 2 under each wind velocity relative to the DC power obtained by allowing the three-phase AC power generated by the wind generator 2 to be smoothed through the full-wave rectification; a current control means 15 for controlling the wind generator 2 so that the output current of the wind generator 2 coincides with the control target current value; and a battery 21 for charging the output power of the wind generator 2 depending on the operation of the current control means 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a charging device for small wind power generation for charging generated power generated by a small wind power generator, and more particularly to a device capable of following a change in wind speed at high speed.

  In a small wind power generation system, the output of a wind power generator is constantly fluctuating and unstable. Therefore, wind power generation power is temporarily stored in a battery, and stable power is supplied from the battery to a load. And as the charging method was disclosed by patent document 1, the method of connecting a wind power generator output directly to a battery after rectification was common.

  Moreover, in a solar power generation system, in order to increase energy conversion efficiency, it is common to add a maximum power point tracking function, but a disclosure example of a technology in which a maximum power point tracking function is added to a charging device for small wind power generation There was very little, and the maximum power point follow-up charging of small power generation has not reached the completed technology.

  Further, the “maximum power control system for a variable speed small wind generator” disclosed in Non-Patent Document 1 outputs an output so that the rotational speed of the wind power generator matches the optimum rotational speed at which the output power becomes maximum at the current wind speed. A maximum power point tracking control technique for charging a battery by controlling current is shown (see FIG. 10). Compared with search-type maximum power point tracking technology such as hill-climbing method, this technology directly controls the rotational speed based on the operating characteristics of the wind power generator, so it is superior in that it can be operated with a high maximum power point tracking rate. Yes.

JP 2000-116007 A Electrology B, 127, 4, pp. 559-565 (2007)

  However, in the method of Patent Document 1, since the output voltage is fixed by the battery (the operating point at a certain wind speed = the rotational speed is only one point at which the output voltage becomes equal to the battery voltage), the maximum power point of the wind power generator Therefore, there is a problem that the operation at the operating point deviated from the above is low and the efficiency of converting wind energy into electric energy is low. In addition, the technique of Non-Patent Document 1 has a problem that an anemometer or a device for measuring the rotational speed of a wind power generator must be provided, and the system becomes complicated and expensive.

  Therefore, in the present invention, in view of the above problems, it is an object to provide a charging device for small wind power generation that can realize charging control excellent in stability, conversion efficiency from wind power to power, and maximum power point tracking with a simple configuration. And

  In order to solve the above-described problem, the small wind power generator charging apparatus according to the invention of claim 1 is obtained by measuring in advance the relationship between the output current, the output voltage, and the rotational speed of the wind power generator at each wind speed. Based on the current output status of the wind power generator, the control target current value generation that calculates and outputs the control target current value of the output current of the wind power generator that maximizes the output power of the wind power generator at the current wind speed Means, current control means for controlling operation so that the output current of the wind power generator matches the control target current value, and power storage means for charging the output power of the wind power generator in accordance with the operation of the current control means. , Configured to provide.

  The charging device for small wind power generation according to the invention of claim 2 is characterized in that the control target current value generating means indicates a maximum current indicating a relationship between an output current and an output current at the maximum power at each output voltage based on the output characteristics. A conditional linear equation is obtained, an output current value at the maximum power at the current wind speed is calculated from the maximum current conditional linear equation, and is output as the control target current value.

  According to a third aspect of the present invention, there is provided a charging device for small wind power generation, wherein the control target current value generating means is based on the output characteristics, and the maximum power indicating the relationship between the output voltage and the output current at the maximum wind speed at each wind speed Obtain the condition curve equation, calculate the output current value at the maximum power at the wind speed when the output voltage at the maximum power becomes the current output voltage, and calculate it from the maximum power condition curve equation, and output it as the control target current value Configured to do.

  According to a fourth aspect of the present invention, there is provided a charging apparatus for small wind power generation, wherein the current control means includes a step-up reactor, a step-up chopper having a switching element that performs a switching operation by a PWM drive signal, the control target current value, and the wind power generation. A first proportional integrator that performs a calculation for proportional and integral control with respect to a difference from the output current of the machine, and a proportional and integral control with respect to the difference between the calculation result of the first proportional integrator and the boost reactor current And a signal generating means for generating the PWM drive signal having a predetermined frequency and pulse width based on the calculation result of the second proportional integrator.

  According to a fifth aspect of the present invention, there is provided a charging apparatus for small wind power generation, wherein the current control means includes a step-down reactor and a step-down chopper having a switching element that performs switching operation by a PWM drive signal, the control target current value, and the wind power generation. A first proportional integrator that performs a calculation for proportional and integral control with respect to a difference between the output current of the machine and a proportional and integral control with respect to a difference between a calculation result of the first proportional integrator and a step-down reactor current And a signal generating means for generating the PWM drive signal having a predetermined frequency and pulse width based on the calculation result of the second proportional integrator.

  According to the first to fifth aspects of the present invention, it is possible to realize charge control excellent in conversion efficiency from wind power to power, stability, and maximum power point tracking with a simple configuration. In particular, according to the invention of claim 3, since the control target current value is calculated only from the output voltage, the software configuration becomes simpler, the software production time can be shortened, and the memory capacity can be reduced.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings.
FIG. 1 is a circuit configuration diagram of a wind power generation system showing an embodiment of a charging device for small wind power generation according to the present invention. The system 1 includes a small wind power generator (hereinafter referred to as a wind power generator) 2 configured to generate three-phase alternating current with a rotor that rotates by receiving wind power at each wind speed, and power generated by the wind power generator 2. Is composed of a small wind power charging device (hereinafter referred to as a charging device) 4 and a load 8.

  The charging device 4 uses the full-wave rectified and smoothed DC power generated by the wind power generator 2 for the output current, output voltage, and rotation speed of the wind power generator 2 under each wind speed. Based on the output characteristics obtained by measuring the relationship in advance, the control target current of the output current of the wind power generator 2 that maximizes the output power of the wind power generator 2 at the current wind speed from the current output status of the wind power generator 2 Depending on the operation of the control target current value generating means 13 that calculates and outputs the value, the current control means 15 that controls the operation so that the output current of the wind power generator 2 matches the control target current value, and the current control means 15 And a battery 21 as power storage means for charging the output power of the wind power generator 2.

  On the output side of the wind power generator 2, a voltage sensor VS61 as first output voltage detection means for detecting the output voltage V1 and a current sensor CS62 as first output current detection means for detecting the output current I1 are provided. ing.

  FIG. 2 shows the relationship between the output current, the output voltage, and the rotational speed of the rotor at each wind speed of the wind power generator 2 in the system 1. The output current of the wind power generator 2 is stepped at each wind speed. It was created based on the data obtained by measuring the change in the output voltage and the rotation speed.

  A group of straight lines drawn by approximating data linearly indicates the relationship between the output current and the output voltage at each wind speed, and the circle indicates the output current and output voltage at the maximum power at each wind speed. The curve is an existence prediction curve of the output current and the output voltage that become the maximum power when the wind speed continuously changes. Here, it is assumed that the wind power generator 2 is a rotor diameter of 0.87 m, a rated output of 85 W (at a wind speed of 11.5 m / s), a rated voltage of 24 V, and a permanent magnet three-phase AC generator.

  FIG. 3 shows a list of values (including values obtained by extending some straight lines) of output current when the output voltage is 10V, 20V, 30V, 40V, and 50V at each wind speed. It is a thing. In addition, an output current value (hereinafter referred to as a maximum power current) Im when the maximum power is reached at each wind speed is also listed.

  FIG. 4 is a maximum current condition linear expression in which the relationship of FIG. 2 is graphed. The output voltage is 10V, 20V, 30V, 40V at each wind speed with the x-axis as the output current and the y-axis as the maximum power current. The output current at 50 V is plotted under the condition (x, y) = (output current, maximum power current at that wind speed), and the points at which the same voltage is obtained at each wind speed are created by linear approximation. . 4, the current wind speed can be assumed from the output voltage and output current, and the maximum power current at the current wind speed can be obtained. For example, when the output voltage is 50 V and the output current is 1.5 A, the output state is only when the wind speed is 9.7 m / s, so the current wind speed is 9.7 m / s and the wind speed is Since the maximum power current at 9.7 m / s is 1.49 A, it is currently operating at the maximum power point.

  The output voltage straight line (maximum current condition linear equation) in FIG. 4 has a certain regularity. The slope of the straight line increases as the output voltage increases, and the y-intercept increases as the output voltage increases. There is also a unique straight line for every voltage. Expressions 1 and 2 are approximate expressions representing the slope a and the y-intercept b of the eigenline with respect to the output voltage, and are created using an interpolation method. Substituting the current output voltage V1 into Equations 1 and 2 to determine the slopes a and y intercepts b of the eigen line corresponding to the current output voltage, a and b obtained from the linear equation of Equation 3 and the current output If the current I1 is substituted, the maximum power current Im at the current wind speed can be obtained.

(Formulas 1-3)

  As described above, the control target current value generation means 13 calculates the maximum power current Im at the current wind speed from the output voltage and output current of the wind power generator 2, and uses this value as the control target current value for the current control means 15 Is given to. These calculations are repeated using a so-called microcomputer at a cycle of 64.1 μs (15600 times per second). For this reason, even when the rotational speed of the rotor of the wind power generator 2 is suddenly changed due to a drastic change in the wind speed, an accurate control target current value can always be generated, and the current control means 15 can output the output voltage of the wind power generator 2. By performing high-speed control so as to match the control target current value, maximum power point tracking control that always keeps the operating point of the wind power generator 2 at the maximum power point can be realized.

Next, a modified example of the control target current value generation unit 13 will be described.
FIG. 5 is also a graph that can be created from FIG. The straight line group indicates the relationship between the output voltage and the output current at each wind speed. The curve is the maximum power condition curve when the wind speed changes continuously, and the output voltage and output current at the maximum power at each wind speed are plotted under the condition (x, y) = (output voltage, output current). This is a curve approximation.
Equation 4 is an approximate expression representing this maximum power condition curve, and is created using an interpolation method. By substituting the current output voltage V1 into Equation 4, the output current Ia at the maximum power at the wind speed at which the output voltage at the maximum power becomes the current output voltage can be obtained.

(Formula 4)

  As described above, the control target current value generating means 14 calculates the output current at the maximum power at the wind speed at which the output voltage at the maximum power becomes the current output voltage from the output voltage V1 of the wind power generator 2, This current is given to the current control means 15 as the control target current value Ia. These calculations are repeated with a period of 64.1 μs (15600 times per second) using a so-called microcomputer (not shown). For this reason, even when the rotation speed of the wind power generator 2 changes suddenly due to a drastic change in wind speed, an accurate control target current value can always be generated, and the output voltage of the wind power generator 2 is controlled by the current control means 15. High-speed control is performed so as to match the current value, and maximum power point tracking control that keeps the operating point of the wind power generator 2 at the maximum power point can be realized.

  Next, the maximum power point following operation of the current control means 15 given the control target current value Ia will be described with reference to FIG. When the operating point on the output current-output voltage characteristic line is at point a on the lower voltage side than the maximum power point at a certain wind speed, since the control target current value Ia <output current I1, the output current control means 15 has I1 Decrease I1 to coincide with Ia. As a result, the operating point approaches the maximum power point when I1 decreases and V1 increases, but Ia increases as V1 increases. When this operation is repeated and the operating point reaches the maximum power point b and Ia = I1, no further current change is likely to occur, and the operation is stabilized. On the contrary, when the operating point on the output current-output voltage characteristic line is at the point c on the higher voltage side than the maximum power point, since the control target current value Ia> the output current I1, the current control unit 15 sets I1 to Ia. Increase I1 to match. As a result, the operating point approaches the maximum power point when I1 increases and V1 decreases, but Ia decreases as V1 decreases. When this operation is repeated and the operating point reaches the maximum power point b and Ia = I1, the operation is still stable.

  Since the above operation is performed at a very high speed, the transition to the maximum power point b is completed in an instant. Since the operation stable point in this control is only the maximum power point where Ia = I1 at any wind speed, maximum power point tracking control can be realized.

  Further, even when the wind speed changes suddenly, the rotational speed of the wind power generator 2 cannot change suddenly due to the moment of inertia of the rotor or the like, and the control speed is much faster than the output change speed of the wind power generator 2, so sometimes It is possible to follow the maximum power point of the generator output at. As described above, since the operating point does not greatly deviate from the maximum power point except when the operation is started, a small wind power charging device with high wind energy → electric energy conversion efficiency can be realized.

Next, an embodiment of current control means will be described. FIG. 7 is a circuit configuration diagram showing the current control means 16 using a step-up chopper.
In the case of a system in which the power stored in the battery 21 is grid-connected, a higher battery voltage is advantageous because there is less loss when the battery voltage is once boosted to a link voltage of about 380 V (input DC voltage of the grid-connected inverter). Become. A boost chopper type current control means 16 for boosting and charging the output voltage of the wind power generator is suitable for the charge control means for grid interconnection use. In this case, the loss associated with boost charging is not so large because the output current of the wind power generator is small.

Generally, when driving a step-up chopper, the current control of the step-up reactor is used for stable operation. In this case, the current control method increases or decreases the step-up reactor current from the current value to make the output voltage of the step-up chopper constant. As in the case of maintaining the voltage, the increase / decrease control of the boost reactor current.
In the boost chopper, the average value of the boost reactor current matches the output current average value of the DC current, so it is only necessary to realize current matching control that matches the average value of the boost reactor current with the control target current value. It was possible. This is because, when sampling the reactor current in digital control, it can be sampled only once in one control period, and the sampling timing cannot be specified. That is, somewhere is sampled once in one cycle T of the IL waveform in FIG. 8, but the sampling value does not match the average value ILav of the reactor current. Sampling here means that an analog value is converted into a digital value by an A / D converter and stored in a memory of a microcomputer. The same applies below.

  In the current control means 16 of FIG. 7A, a boost reactor L1 and a backflow prevention diode D1 are connected in series to the positive output stage of the wind power generator 2, and the output side of the boost reactor L1 is a MOSFET as a switching element Q. A boost chopper is configured by grounding. Here, CS62 is a current sensor as first output current detection means for detecting the output current I1, CS63 is a current sensor as second output current detection means for detecting the reactor current IL1, and VS61 is a first output for detecting the output voltage V1. It is a voltage sensor as a voltage detection means.

  7B, the current control means 16 calculates the difference between the LPF 65 for obtaining the output current average value I1av from the output current I1 of the wind power generator 2, and the control target current value and the output current average value I1av. The first adder / subtractor 31 that performs the calculation, the first proportional integrator 32 that performs the calculation for the proportional and integral control with respect to the calculation result of the first adder / subtractor 31, the calculation result of the first proportional integrator 32, and the boost reactor current A second adder / subtractor 33 that performs a difference operation with respect to IL1, a second proportional integrator 34 that performs an operation for proportional and integral control on the operation result of the second adder / subtractor 33, and an operation of the second proportional integrator 34 Based on the result, a signal generating means 36 for generating a PWM drive signal G having a predetermined frequency and pulse width inputted to the switching element Q is provided.

  In the above configuration, the generator output current I1 is detected by the current sensor CS62 provided between the three-phase full-wave rectifier SR and the smoothing capacitor C of the wind power generator 2. This current waveform also has ripples associated with three-phase full-wave rectification, but because it has a lower frequency than reactor current ripple, it can be sampled several tens of times per ripple period, so I1 is accurately taken into the microcomputer. be able to. Next, the sampling value I1 is input to the low-pass filter LPF65 to obtain the output current average value I1av, the difference between the control target current value Im (Ia) and the output current average value I1av is input to the first proportional integrator 32, and the reactor A current command value is generated. This reactor current command value increases or decreases the reactor current so that the output current average value I1av matches the control target current value, and realizes the reactor current increase / decrease control. The difference between the reactor current command value (PI1 output value) and the sampling value of the reactor current IL1 detected by the current sensor CS63 is input to the second proportional integrator 34, and PWM drive is performed from the output of the second proportional integrator 34 by the triangular wave comparison method. A signal G is generated to switch the switching element Q.

  While the switching element Q is on, energy is stored in the reactor, and while the switching element Q is off, the energy stored in the reactor is released to the battery 21 via the backflow prevention diode D1, and boost charging is performed. Thus, in the step-up chopper method, charging is performed with a pulse current.

  In addition, an Example is a system which charges a 48V battery with the rated voltage 24V (for 24V battery connection), and is 4m which becomes (charge electric power)> (control electric power at the time of boosting + circuit loss at the time of boosting) Boosting charge by maximum power point tracking control of generator output at wind speed of / s or more, and control is stopped when the output voltage at maximum power exceeds 9m / s exceeding 48V (Q continuous off) The generator-battery direct charging is performed by the circuit of WG-L1-D1-BT1. Here, sampling control, calculation of LPF, PI1, PI2, and generation of a PWM control signal all depend on processing of software of the microcomputer. The same applies hereinafter.

  According to the above-described configuration, it is possible to realize control for accurately matching the output current of the wind power generator 2 to the control target current value that changes every moment by increasing / decreasing the boost reactor current.

Next, another embodiment of the current control means will be described. FIG. 9 is a circuit configuration diagram showing current control means 17 using a step-down chopper.
Even if a step-down chopper is used, the maximum power point following charging of a small wind power generator can be realized. The step-down chopper charging device has a demerit that it has a large loss when boosting to a link voltage of about 380 V during grid connection operation (input DC voltage of the grid connection inverter) due to the low battery voltage. When the output capacity of a small wind power generator is small, there is the merit that it can be directly connected to the battery at times, and that it can be charged at the maximum power point without being clamped by the battery voltage like the step-up chopper type charging device in strong winds. Become advantageous.

  In general, when driving a step-down chopper, smoothing reactor current control is used to stabilize the operation. In this case, the current control method increases or decreases the smoothing reactor current from the current value to make the output voltage of the step-down chopper constant. As in the case of maintaining the current, the increase / decrease control of the smooth reactor current is performed. In the step-down chopper, the smoothing reactor current is larger than the power supply current of the step-down chopper.

  9A, a MOSFET as a switching element Q and a smoothing reactor L2 are connected in series to the positive output stage of the wind power generator 2, and the output side of the switching element Q is grounded by a free-wheeling diode D2. The step-down chopper is configured. Here, CS62 is a current sensor as first output current detection means for detecting the output current I1, CS64 is a current sensor as third output current detection means for detecting the reactor current IL2, and VS61 is a first output for detecting the output voltage V1. It is a voltage sensor as a voltage detection means.

  Further, as shown in FIG. 9B, the current control means 17 performs the calculation results of the LPF 65, the first adder / subtractor 31, the first proportional integrator 32, and the first proportional integrator 32, as in FIG. 7B. PWM having a predetermined frequency and pulse width input to the switching element Q based on the calculation results of the second adder / subtractor 33, the second proportional integrator 34, and the second proportional integrator 34 that perform a difference calculation between the current and the smoothing reactor current IL2. It comprises signal generation means 36 for generating the drive signal G.

A generator output current I1 is detected by a current sensor CS62 provided between the three-phase full-wave rectifier SR and the smoothing capacitor C of the wind power generator 2. This current waveform also has ripples associated with three-phase full-wave rectification, but because it has a lower frequency than the reactor current ripple, it can be sampled several tens of times per ripple period, so I1 is accurately taken into the microcomputer. be able to.
Next, the sampling value I1 is input to the low-pass filter LPF65 to obtain the output current average value I1av, and the difference between the control target current value Im (Ia) and the output current average value I1av is input to the first proportional integrator 32 for smoothing. Reactor current command value is generated. This smoothing reactor current command value increases or decreases the reactor current so that the output current average value I1av matches the control target current value, and realizes smoothing reactor current increase / decrease control. The difference between the smoothed reactor current command value (PI1 output value) and the sampling value of the smoothed reactor current IL2 detected by the current sensor CS64 is input to the second proportional integrator 34, and the output of the second proportional integrator 34 is used for the triangular wave comparison method. A PWM drive signal G is generated to switch the switching element Q.

  While the switching element Q is on, energy is stored in the smoothing reactor L2, and the charging current increases. While the switching element Q is off, the charging current continues to flow while decreasing. This is because the energy stored in the smoothing reactor L2 is released to the battery 21 via the freewheeling diode D2. Thus, in the step-down chopper method, step-down charging is performed without interruption of the charging current.

  The embodiment of FIG. 9 is a system that charges a 24V battery with a wind power generator with a rated voltage of 24V (for connecting to a 24V battery), and generates power with a circuit of WG-Ry-L2-BT2 at a wind speed of less than 4 m / s. Machine-battery direct charging. The maximum power point following charging of the small wind power generator by the step-down operation is performed at a wind speed of 4 m / s or more such that (charging power)> (control power during boosting + circuit loss during boosting). Here, Ry is a relay, which is closed during direct charge and open during control charge.

  According to the above configuration, the smoothing reactor current different from the power source current (generator output current) is controlled to increase and decrease, and the control to accurately match the output current of the wind power generator with the control target current value that changes every moment can be realized. .

  In addition, this invention is not limited to the said embodiment, It is also possible to change suitably the shape and structure of each part in the range which does not deviate from the meaning of this invention.

It is a circuit block diagram which shows one Embodiment of the charging device for small wind power generation concerning this invention. It is a rotation speed-output voltage of a wind power generator, an output current output characteristic figure. It is an output voltage-output current output list in each wind speed of a wind power generator. It is an output current-maximum electric power current output characteristic figure of a wind power generator. It is an output voltage-output current output characteristic figure of a wind power generator. FIG. 6 is a relationship diagram between a control target current value and an output current. As for the current control means using the boost chopper, (a) is an overall circuit configuration diagram, and (b) is a partial circuit configuration diagram. It is a figure of IL waveform. Regarding current control means using a step-down chopper, (a) is an overall circuit configuration diagram, and (b) is a partial circuit configuration diagram. It is a block diagram which shows a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... System, 2 ... Wind generator, 4 ... Charging device, 8 ... Load, 13, 14 ... Control target current value generation means, 15, 16, 17 ... Current control means, 21 ... Battery , 31 ··· First adder / subtractor, 32 ··· First proportional integrator, 33 ··· Second adder / subtractor, 46 ··· Second proportional integrator, 36 ··· Signal generating means, 48 ··· Control signal generating means.

Claims (5)

Wind power generation at the current wind speed from the current output status of the wind power generator based on the output characteristics obtained by measuring in advance the relationship between the output current of the wind power generator, the output voltage, and the rotational speed of the rotor under each wind speed. A control target current value generating means for calculating and outputting the control target current value of the output current of the wind power generator that maximizes the output power of the machine;
Current control means for controlling the operation so that the output current of the wind power generator matches the control target current value;
Power storage means for charging the output power of the wind power generator according to the operation of the current control means,
A charging device for small wind power generation. The control target current value generating means includes
Based on the output characteristics, a maximum current condition linear expression showing the relationship between the output current and the output current at the maximum power at each output voltage is obtained,
The output current value at the time of maximum power at the current wind speed is calculated from the maximum current condition linear equation, and is output as the control target current value.
The charging device for small wind power generation according to claim 1. The control target current value generating means includes
Based on the output characteristics, obtain a maximum power condition curve equation showing the relationship between the output voltage and the output current when the maximum power at each wind speed,
An output current value at the maximum power at the wind speed when the output voltage at the maximum power becomes the current output voltage is calculated from the maximum power condition curve equation and is output as the control target current value.
The charging device for small wind power generation according to claim 1. The current control means includes
A step-up reactor and a step-up chopper having a switching element that performs a switching operation by a PWM drive signal;
A first proportional integrator that performs calculations for proportional and integral control on the difference between the control target current value and the output current of the wind power generation;
A second proportional integrator that performs a calculation for proportional and integral control on the difference between the calculation result of the first proportional integrator and the boost reactor current;
Signal generating means for generating the PWM drive signal having a predetermined frequency and pulse width based on the calculation result of the second proportional integrator,
The charging device for small wind power generation according to any one of claims 1 to 3. The current control means includes
A step-down chopper having a step-down reactor and a switching element that performs a switching operation by a PWM drive signal;
A first proportional integrator that performs calculations for proportional and integral control with respect to the difference between the control target current value and the output current of the wind power generator;
A second proportional integrator that performs a calculation for proportional and integral control on a difference between a calculation result of the first proportional integrator and a step-down reactor current;
Signal generating means for generating the PWM drive signal having a predetermined frequency and pulse width based on the calculation result of the second proportional integrator,
The charging device for small wind power generation according to any one of claims 1 to 3.

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