JP2014207835A - Power conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conditioner which allows for efficient use of generated power while avoiding increase in the manufacturing cost.SOLUTION: In a power conditioner for converting a DC power generated from a fuel cell into an AC power that can be interconnected with a system, a microcomputer having two PWM output sections is used as the microcomputer 61 in a control unit. A PWM signal outputted from one PWM output section 62 is converted into a substantially trapezoidal waveform, and a PWM signal outputted from the other PWM output section 63 is converted into a substantially linear waveform. Both waveforms are compared by means of a comparator 66, and a PWM signal for inverter gate signal is generated. Thereafter, the duty ratio of the inverter gate signal is adjusted finely, by controlling the duty ration of the PWM signal outputted from the PWM output section 63 finely.

Description

  The present invention relates to a power conditioner, and more particularly to a power conditioner for a fuel cell.

  In recent years, household fuel cell power generation systems have attracted attention from the viewpoint of promoting the use of clean energy.

  As is well known, this type of fuel cell power generation system converts DC power generated by a fuel cell into AC power that can be connected to a system such as a commercial power source by a power conditioner (system-connected inverter device). However, in order to increase the power generation efficiency of the system, it is necessary to make the power supplied to the grid as close as possible to the power generated by the fuel cell.

  Therefore, this type of fuel cell power generation system is configured to generate a PWM signal for driving the inverter unit (bridge type inverter circuit) of the power conditioner by the control unit (specifically, a microcomputer) of the power conditioner. The duty ratio of the PWM signal is controlled by a microcomputer to adjust the power supplied to the system side (see, for example, Patent Document 1).

  Specifically, as shown in FIG. 5, the PWM output part of the microcomputer a is configured to output a PWM signal for driving the inverter (inverter PWM), and this PWM signal is divided into four by a logic circuit (not shown). The PWM signal is input to the control circuit of each switching element.

JP-A-8-98541

  However, such conventional power conditioners have the following problems, and improvements have been desired.

  That is, in the configuration in which the PWM signal output from the PWM output unit of the microcomputer is applied to the switching element of the inverter unit via the logic circuit and the drive circuit to control the inverter unit, the adjustment of the power supplied to the system side is as follows. Because it depends on the performance (PWM resolution) of the microcomputer that generates the PWM signal, wasteful power that cannot be used unless the PWM resolution of the microcomputer is sufficient is generated, and as a result, the efficiency of the system is not sufficiently increased. There was a fear. For example, if the power supplied to the grid is adjusted in units of 20W due to the performance of the microcomputer, a maximum of 20W (10W on average) is wasted, and the output power is 700W. If so, the power generation efficiency would be reduced by a maximum of 2.8% (1.4% on average).

  Such a problem can be solved by using a high-performance microcomputer (high PWM resolution) for controlling the inverter unit, but the microcomputers that can be selected by design are limited in correspondence with the use of a high-performance microcomputer. Therefore, there exists a problem that the manufacturing cost of a power conditioner becomes high.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a power conditioner that can efficiently use generated power while avoiding an increase in manufacturing cost. There is.

  In order to achieve the above object, a power conditioner according to claim 1 of the present invention is a power conditioner that converts output power of a power generation unit into AC power that can be connected to a system. And a control unit including a first PWM output unit that outputs a first PWM signal, a second PWM output unit that outputs a second PWM signal, and a first PWM output unit output from the first PWM output unit. A first signal conversion unit that converts a 1PWM signal into a pulse signal that rises and / or falls slowly, and a second PWM signal that is output from the second PWM output unit and converts the PWM signal into a substantially linear waveform. The output signal of the signal converter, the output signal of the first signal converter and the output signal of the second signal converter are compared, and the switching element driver of the inverter unit is compared. A drive signal generator for generating a third PWM signal for controlling the duty ratio of the third PWM signal by controlling a duty ratio of the second PWM signal output from the second PWM output unit. A control structure for controlling is provided.

  In the power conditioner according to the first aspect, the PWM signal (third PWM signal) for driving the switching element of the inverter unit is two PWM output units (first PWM output unit and second PWM output unit) provided in the control unit. Are generated on the basis of two types of PWM signals (first PWM signal and second PWM signal) output from. Specifically, a signal in which the rise and / or fall of the first PWM signal output from the first PWM output unit is blunted (for example, a signal having a substantially trapezoidal waveform in which both rise and fall are blunted) and Then, the second PWM signal output from the second PWM output unit is blunted and compared with a signal having a substantially linear waveform by the drive signal generation unit to generate a third PWM signal. That is, in generating the third PWM signal, the control unit controls the duty ratio of the second PWM signal (that is, changes the duty ratio), so that the second signal conversion unit as shown in FIG. The signal output from (the “fine adjustment PWM” in the figure) is moved up and down to change the intersection position with the signal (“inverter PWM” in the figure) output from the first signal converter, and the third PWM signal Control the duty ratio. That is, the duty ratio of the third PWM signal, that is, the PWM signal that drives the switching element of the inverter unit, is finely adjusted according to the change in the duty ratio of the second PWM signal.

  A power conditioner according to a second aspect of the present invention is the power conditioner according to the first aspect, wherein the third PWM signal output from the drive signal generation unit is connected to the inverter unit via a predetermined logic circuit. It is input to the control terminal of each switching element which comprises.

  In the power conditioner according to the second aspect, the third PWM signal output from the drive signal generator is input to the control terminal of the switching element after being input to the logic circuit. Therefore, a plurality of switching elements can be driven using one third PWM signal, for example, by branching the third PWM signal with this logic circuit or inverting a part thereof.

  A power conditioner according to a third aspect of the present invention is the power conditioner according to the first or second aspect, wherein the control unit is configured so that an output current value from the power conditioner becomes an output target current value. It has a control structure for controlling the duty ratio of the first PWM signal.

  In the power conditioner according to claim 3, since the duty ratio of the first PWM signal is controlled so that the output current value of the power conditioner is the output target current value, the output current of the power conditioner is used as the output target current. It is possible to approach the value, and the power generated by the power generation unit can be used efficiently.

  A power conditioner according to a fourth aspect of the present invention is the power conditioner according to any one of the first to third aspects, wherein the controller is configured such that an input current value to the power conditioner is an input target current value. As described above, the control structure for controlling the duty ratio of the second PWM signal is provided.

  In the power conditioner according to the fourth aspect, the duty ratio of the second PWM signal is controlled so that the input current value to the power conditioner is the input target current value. That is, the second PWM signal that finely adjusts the third PWM signal input to the control terminal of the switching element of the inverter unit is controlled based on the DC input current and the input target current value. There is little influence of time delay due to conversion (converted into a linear signal) in the unit.

  The power conditioner according to claim 5 of the present invention is provided with input current control means for controlling the input current value to the power conditioner to be the input target current value in the power conditioner according to claim 4. When the deviation between the input current value to the power conditioner and the input target current value is greater than or equal to a predetermined value, the control unit maintains the duty ratio of the second PWM signal at a constant value. On the other hand, when the deviation is less than a predetermined value, a control configuration is provided for controlling the duty ratio of the second PWM signal while making the input current control by the input current control means dead zone processing. It is characterized by that.

  In the power conditioner according to the fifth aspect, when the deviation between the input current value to the power conditioner and the input target current value is equal to or larger than a predetermined value, the duty ratio of the second PWM signal is maintained at a constant value. Only the input current control by the input current control means is performed without fine adjustment by the signal. On the other hand, when the deviation is less than a predetermined value, the input current control by the input current control means is set as a dead zone process, and in this state, the duty ratio of the second PWM signal is controlled to finely adjust the third PWM signal to be supplied to the inverter unit.

  A power conditioner according to a sixth aspect of the present invention is the power conditioner according to any one of the first to fifth aspects, wherein the power generation unit includes a fuel cell. That is, the power conditioner according to claim 6 is used as a power generation unit for a power generation system having a fuel cell such as a solid oxide fuel cell (SOFC) or a polymer electrolyte fuel cell (PEFC) as a power generation unit. Used for interconnection.

  In the present invention, the PWM signal (third PWM signal) for driving the switching element of the inverter unit is output from two PWM output units (first PWM output unit and second PWM output unit) provided in the control unit. Since the signal is generated based on the signals (the first PWM signal and the second PWM signal), the third PWM signal to be supplied to the inverter unit can be finely finely adjusted even by a control unit having a low PWM resolution. Therefore, according to the present invention, it is possible to provide a power conditioner that can efficiently use generated electric power without using an expensive microcomputer with high PWM resolution in the control unit.

1 is a block diagram showing a schematic configuration of a fuel cell power generation system using a power conditioner according to the present invention. It is a block diagram which shows schematic structure of the production | generation circuit which produces | generates an inverter gate signal in the power conditioner. It is explanatory drawing which shows the production | generation process of the inverter gate signal in the same inverter, FIG.3 (a) has shown typically the method of fine adjustment of the duty ratio of an inverter gate signal, FIG.3 (b) is a figure. The rising edge of the waveform in 3 (a) is shown enlarged. It is explanatory drawing which shows the control method of the inverter gate signal in the same power conditioner, Fig.4 (a) has shown typically an example of the control method of an inverter gate signal, FIG.4 (b) shows the inverter gate signal of FIG. FIG. 4C shows the problem of time delay when fine adjustment is performed based on the output current, and FIG. 4C shows an improved state by performing fine adjustment of the inverter gate signal based on the input current. The output circuit of the inverter gate signal in the conventional power conditioner is shown.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic configuration of a fuel cell power generation system using a power conditioner 1 according to the present invention.

  A power conditioner 1 shown in FIG. 1 is a grid-connected inverter device that converts DC power generated by a fuel cell (power generation unit) 2 into AC power that can be linked to a grid 3 such as a commercial power source. The converter unit 4, the inverter unit 5, and the control unit 6 that controls the converter unit 4 and the inverter unit 5 are provided as main units.

  The converter unit 4 is composed of a DC / DC converter circuit that boosts the direct current voltage generated by the fuel cell 2 to a predetermined voltage. For this converter unit 4, a known converter circuit, for example, a boost push-pull type converter circuit is used. The input side of the converter unit 4 is connected to the fuel cell 2, and the output side is connected to the input side of the inverter unit 5 via a DC link capacitor (DC link unit) 7. Reference numeral 8 denotes an input current sensor that detects an input current to the converter unit 4 (power conditioner 1). Reference numeral 9 denotes a voltage sensor that detects an input voltage of the inverter unit 5 (voltage of the DC link unit). Both the sensors 8 and 9 are connected to the control unit 6 so that the control unit 6 can detect the input current to the power conditioner 1 and the voltage of the DC link unit 7. Although not shown, an input voltage sensor that detects an input voltage to the power conditioner 1 (an output voltage of the fuel cell 2) is also provided, so that the control unit 6 can also detect an input voltage to the power conditioner 1. It has become.

  The inverter unit 5 includes a DC / AC inverter circuit that converts the DC voltage boosted by the converter unit 4 into an AC voltage that can be linked to the system 3. In this embodiment, this inverter part 5 is comprised with the well-known bridge type inverter circuit. In other words, the inverter unit 5 gives an inverter gate signal (switching element drive signal) to a plurality (four in the illustrated example) of FETs (switching elements) 10, 10,... The drive circuit 11 and a logic circuit 12 that distributes an inverter gate signal generated as described later to the drive circuit 11 are configured as main parts.

  On the output side of the inverter unit 5, a low-pass filter (coil 13 and capacitor 14) that removes high-frequency components from the output of the inverter unit 5 is provided. It is connected to the system 3 side via an interconnection relay. Reference numeral 15 denotes an output current sensor that detects the output current of the inverter unit 5 (power conditioner 1), and 16 denotes an output voltage sensor that detects the output voltage of the inverter unit 5. Both the sensors 15 and 16 are also control units. 6, and the control unit 6 can detect the output current and output voltage of the power conditioner 1.

  The control unit 6 is a control device for controlling each part of the power conditioner 1 such as the converter unit 4 and the inverter unit 5 described above. The control unit 6 includes a microcomputer 61 (see FIG. 2) as a control center. It has been.

  The microcomputer 61 is provided with a control program and control data for controlling each part of the power conditioner 1, and the control part 6 performs various controls such as control of the inverter part 5 described later by the microcomputer 61. It is like that.

  FIG. 2 shows an inverter gate signal generation circuit for driving the inverter unit 5. As shown in FIG. 2, the power conditioner 1 according to the present invention receives an inverter gate signal, that is, a PWM signal (third PWM signal) for driving the FETs 10, 10,. The two types of PWM signals output from the PWM output units 62 and 63 are used for generation.

  Specifically, the microcomputer 61 is a microcomputer having two or more PWM output units capable of outputting a PWM signal, and one of the PWM output units (first PWM output unit) 62 is an inverter gate signal. It is used as a signal output unit (indicated as “inverter PWM” in FIG. 2) that outputs a base PWM signal (first PWM signal), and the other PWM output unit (second PWM output unit) 63 performs fine adjustment of the inverter gate signal. 2 is used as a signal output unit (shown as “finely adjusted PWM” in FIG. 2) for outputting a PWM signal (second PWM signal).

  The first PWM signal output from the first PWM output unit 62 has a substantially trapezoidal shape in which the rising and falling waveforms of the pulse of the PWM signal are dulled (that is, with a certain time width at the rising and rising of the waveform). Is input to a filter circuit (first signal conversion unit) 64 that converts the signal into a pulse signal having the waveform shown in FIG. It is comprised so that. On the other hand, the second PWM signal output from the second PWM output unit 63 is a filter circuit (second signal conversion unit) that converts the pulse of the PWM signal into a signal having a substantially linear waveform by strongly dulling the rise and fall of the pulse of the PWM signal. The filter circuit 65 converts the signal into a signal having a substantially linear waveform and inputs the signal to a comparator (drive signal generation unit) 66.

  As shown in FIG. 3A, the comparator 66 includes a signal input from the filter circuit 64 (indicated as “inverter PWM” in FIG. 3) and a signal input from the filter circuit 65 (in FIG. The PWM signal (third PWM signal) to be an inverter gate signal is generated by comparing the “adjustment PWM” and the display), and the inverter gate signal generated by the comparator 66 is input to the logic circuit 12. (Details will be described later).

  The duty ratio of the inverter gate signal generated by the comparator 66 is controlled by controlling (changing) the duty ratio of the second PWM signal (fine adjustment PWM) output from the second PWM output unit 63. ing. That is, when the duty ratio of the second PWM signal (fine adjustment PWM) is changed, the substantially linear signal (fine adjustment PWM) shown in FIG. Therefore, when the duty ratio is changed so that the Hi period of the second PWM signal becomes longer, the “fine adjustment PWM” in FIG. 3A increases according to the change amount, and the Hi period of the inverter gate signal becomes longer. Tweaked as follows. On the contrary, when the duty ratio is changed so that the Hi period of the second PWM signal is shortened, the “fine adjustment PWM” in FIG. 3A is lowered according to the change amount, and the Hi period of the inverter gate signal is shortened. Finely adjusted to

  FIG. 3B is an enlarged view of the rising portion of the substantially trapezoidal signal (inverter PWM) in FIG. Here, in FIG. 3B, ΔV indicates a finely adjustable range by the second PWM signal. If the time width that can be adjusted in this finely adjustable range ΔV is Δtu, and the same time width in the falling portion (not shown) is Δtd, Δtu + Δtd is set so that the time width is equal to or greater than the PWM resolution of the microcomputer 61 (filter circuit In addition, the resolution can be improved and the duty of the inverter gate signal can be continuously changed in minute units. It becomes like this.

  Specifically, for example, the first PWM output unit 62 of the microcomputer 61 can adjust the pulse width of the first PWM signal every 25 ns, Δtu + Δtd is 50 ns, and the second PWM output unit 63 has a voltage range of ΔV of 1000 points. If it is possible to adjust, when the inverter PWM signal is generated by the first PWM output unit 62 without using the control of the present invention, the Hi period and Lo period of the inverter gate signal are adjusted by a multiple of 25 ns. On the other hand, when the present invention is used, the Hi period and Lo period of the inverter gate signal can be adjusted by a multiple of 50 ps. That is, if the present invention is used, the inverter gate signal can be finely controlled without using a microcomputer with high PWM resolution.

  In the above-described embodiment, the filter circuit 64 generates a substantially trapezoidal signal by dulling both the rising and falling waveforms of the pulse of the first PWM signal. It is also possible to configure so that only one of the rising edge or falling edge of the pulse of the 1PWM signal is blunted. In other words, the filter circuit 64 can be configured so that one of the rising edge and the falling edge of the first PWM signal is changed to a substantially right-angled triangular waveform. When adopting a configuration in which only one of the rising edge and falling edge of the first PWM signal is dulled as described above, only one of Δtu and Δtd is set to have a time width equal to or greater than the PWM resolution of the microcomputer 61. Is done.

  In the above-described embodiment, the filter circuit 65 has a configuration in which both the rising edge and the falling edge of the pulse of the second PWM signal are blunted to generate a substantially linear signal (in particular, a linear waveform in the illustrated example). Since the signal blunted by the filter circuit 65 is a signal for comparison with the first PWM signal after waveform conversion (for fine adjustment of the inverter gate signal), it does not have to be as straight as the illustrated example. For example, the waveform may be a gentle “heavy” shape.

  Next, an inverter control method in the power conditioner 1 configured as described above will be described.

  In the power conditioner 1 of the present invention, the microcomputer 61 causes the output current value detected by the output current sensor 15 to be the output target current value set in the control unit 6 (that is, matches both). The duty ratio of the first PWM signal output from the first PWM output unit 62 is controlled. Specifically, the control unit 6 feeds back the output current of the power conditioner 1 and controls the first PWM signal so that the output current of the power conditioner 1 becomes the output target current value.

  Here, the output target current value in this control is calculated by the control unit 6. Specifically, for example, the control unit 6 (the microcomputer 61) inputs the power conditioner 1 from the input voltage value to the power conditioner 1 and the input target current value determined according to the generated power of the fuel cell 2. The output power value is calculated by calculating the input power value and multiplied by the conversion efficiency of the power conditioner 1, and further divided by the voltage of the grid 3 to set the output target current value.

  On the other hand, the duty ratio of the second PWM signal output from the second PWM output unit 63 is determined by the microcomputer 61 so that the input current value detected by the input current sensor 8 becomes the input target current value (that is, the two match). Control.

  By the way, since the 2nd PWM signal output from the 2nd PWM output part 63 is a signal for performing fine adjustment of an inverter gate signal as mentioned above, it can also be controlled based on an output current value. However, since the conversion from the second PWM signal to the substantially linear signal has a large time delay, even if the timing output from the microcomputer 61 is the optimum value, the time when the inverter gate signal is finely adjusted by this time delay. Then it may not be optimal. In particular, since the output current controlled by the inverter unit 5 is alternating current, as shown in FIG. 4B, there is a possibility that the output target current value and the actual output current value are greatly shifted due to time delay.

  Therefore, in the power conditioner 1 shown in this embodiment, the inverter gate signal is finely adjusted based on the input current value and the input target current value. That is, since both the input current value and the input target current value are direct current, the influence of time delay is reduced as shown in FIG.

  Next, timing for performing fine adjustment of the inverter gate signal with the second PWM signal will be described.

  As described above, the power conditioner 1 shown in the present embodiment has a configuration that controls the second PWM signal so that the input current value becomes the input target current value. In this type of power conditioner 1, In addition to the control of the input current by the second PWM signal, the input current for performing the control for matching the input current value with the input target current value so that the input current value to the power conditioner 1 is in an optimum state. Control means (not shown) are provided.

  The input current control means for controlling the input current value is well known and will not be described in detail. However, the input current control means is provided in either the converter unit 4 or the inverter unit 5 and the configuration provided in either of them. Even so, the input current control means is configured to perform the input current control so that the deviation (absolute value) between the input current value and the input target current value is less than a predetermined value X set in advance. .

  Therefore, as shown in this embodiment, when the configuration in which the input current value is controlled by the second PWM signal is adopted, the control of the input current value by the second PWM signal competes with the input current control by the input current control means, and hunting is performed. Inconvenience such as may occur.

  Therefore, in the power conditioner 1 shown in the present embodiment, in order to avoid such inconvenience, the control unit 6 has an input current value to the power conditioner 1 and an input target as shown in FIG. When the deviation (absolute value) of the current value is greater than or equal to the predetermined value X, the input current control means performs input current control while maintaining the duty ratio of the second PWM signal (fine adjustment PWM) at a constant value, while the deviation ( When the (absolute value) is less than the predetermined value X, the input current control by the input current control means is maintained and the dead band process is configured to control the duty ratio of the second PWM signal, thereby avoiding control conflicts. doing.

  In addition, the method for finely adjusting the inverter gate signal has a time delay associated with the signal waveform conversion described above, and thus may not be able to follow the rapid fluctuation of the input current value. Since the deviation from the input target current value becomes large and the input current control is performed by the input current control means, it is possible to avoid the occurrence of a situation where the follow-up is not in time.

  Thus, according to the power conditioner 1 of the present invention, the inverter gate signal (third PWM signal) for driving the FET 10 of the inverter unit 5 is provided with the two PWM output units 62 provided in the microcomputer 61 constituting the control unit 6. , 63 is generated based on the two types of PWM signals output from the inverter 63, so that the duty of the inverter gate signal can be finely finely adjusted even if a microcomputer having a low PWM resolution is used. Therefore, according to the present invention, it is possible to provide a power conditioner that can efficiently use generated power without using an expensive microcomputer with high PWM resolution.

  The above-described embodiment shows a preferred embodiment of the present invention, and the present invention is not limited to this, and various design changes can be made within the scope of the invention.

  For example, in the above-described embodiment, a signal to be compared with the substantially trapezoidal signal generated based on the first PWM signal is output from the PWM output unit 63 of the microcomputer 61, and the waveform is converted into a substantially linear shape by the filter circuit 65. Although the configuration is shown, if the D / A conversion output unit is provided in the microcomputer 61, a substantially linear signal can be output from the D / A conversion output unit.

  Moreover, although the case where the switching element of the inverter part 5 was comprised by FET10 was shown in embodiment mentioned above, switching elements other than FET (for example, a transistor) can also be used.

  In the embodiment described above, detailed description of the fuel cell 2 is omitted. However, as the fuel cell, a fuel cell such as a solid oxide fuel cell (SOFC) or a solid polymer fuel cell (PEFC) is used. It can be suitably used.

1 Power conditioner 2 Fuel cell (power generation part)
3 System 4 Converter unit 5 Inverter unit 6 Control unit 7 DC link capacitor (DC link unit)
8 Input Current Sensor 9 Inverter Input Voltage Sensor 10 Inverter FET (Switching Element)
DESCRIPTION OF SYMBOLS 11 Drive circuit 12 Logic circuit 15 Output current sensor 16 Output voltage sensor 61 Microcomputer 62 1st PWM output part 63 2nd PWM output part 64 Filter circuit (1st signal conversion part)
65 Filter circuit (second signal converter)
66 Comparator (Drive signal generator)

Claims (6)

In a power conditioner that converts the output power of the power generation unit into AC power that can be linked to the system, and having a switching element that is driven by a PWM signal in the inverter unit,
A control unit including a first PWM output unit that outputs a first PWM signal and a second PWM output unit that outputs a second PWM signal;
A first signal conversion unit that converts the first PWM signal output from the first PWM output unit into a pulse signal that rises and / or blunts;
A second signal converter that dulls the second PWM signal output from the second PWM output unit and converts it into a substantially linear waveform;
A drive signal generator that compares the output signal of the first signal converter and the output signal of the second signal converter and generates a third PWM signal for driving the switching element of the inverter;
The power conditioner includes a control configuration in which the control unit controls a duty ratio of the third PWM signal by controlling a duty ratio of the second PWM signal output from the second PWM output unit.   2. The power condition according to claim 1, wherein the third PWM signal output from the drive signal generation unit is input to a control terminal of each switching element constituting the inverter unit via a predetermined logic circuit. Na.   3. The control unit according to claim 1, wherein the control unit has a control configuration for controlling a duty ratio of the first PWM signal so that an output current value from the power conditioner becomes an output target current value. 4. The listed inverter.   4. The control unit according to claim 1, wherein the control unit has a control configuration for controlling a duty ratio of the second PWM signal so that an input current value to the power conditioner becomes an input target current value. 5. The power conditioner as described in any one. Comprising input current control means for controlling the input current value to the inverter to be the input target current value;
When the deviation between the input current value to the power conditioner and the input target current value is greater than or equal to a predetermined value, the control unit is configured to maintain the duty ratio of the second PWM signal at a constant value while maintaining the input current by the input current control means. On the other hand, when the deviation is less than a predetermined value, there is provided a control configuration for controlling the duty ratio of the second PWM signal while making the input current control by the input current control means a dead band process. The power conditioner according to claim 4.   The power conditioner according to claim 1, wherein the power generation unit includes a fuel cell.

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