Power oscillation division circuit and surplus power utilization system

Abstract

The present invention distributes surplus power while intervening between a power generation system and a power conditioner, and enables maximum power point control in the power conditioner. 【Solution means】 A power distribution circuit arranged in the power grid between the power generation system and the power conditioner, comprising the following configuration. The branch connection part branches the power generation line of the power generation system into a main line leading to the power conditioner and other distribution lines. The distribution power switch part intermittently switches the distribution line to extract the distribution power. The distribution power receiving part takes in the distribution power and sends it to the distribution power supply destination. The pulsation suppression part suppresses the pulsating voltage applied to the power generation system due to power distribution while passing the voltage change caused by the maximum power point control through the power generation line.

Description

Technical Field

[0001] The present invention relates to a power distribution circuit and a surplus power utilization system.

Background Art

[0002] Conventionally, in a circuit built into a power conditioner, a technique for distributing surplus power of a power generation system such as solar power or wind power has been proposed.

[0003] For example, in paragraph 0030 and FIG. 4 of Patent Document 1, as a built-in circuit of a power conditioner, "when the DC bus voltage becomes equal to or higher than the surplus power detection voltage, the control unit outputs a charging current command. At this time, it is determined that surplus power corresponding to the charging current command has occurred, and the corresponding power is charged to the storage battery. The power flowing backward to the system is reduced by the amount charged to the storage battery." There is a description to this effect.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] A power conditioner has a function of performing maximum power point control (such as MPPT control) on a power generation system.

[0006] In this maximum power point control, the power conditioner maximizes the receivable power (such as the product of the received current value and the received voltage value) by observing the received current while shifting the received voltage by load control at the power reception inlet or the like.

[0007] If it is a circuit built into the power conditioner as in Patent Document 1, after completing this maximum power point control, the surplus power may be distributed. In this case, the circuit operates independently in the order of "surplus power distribution" following "maximum power point control". Therefore, the "surplus power distribution" does not circuitously interfere with the "maximum power point control". As a result, Patent Document 1 is excellent in that there is no need to consider the operational interference between the "maximum power point control" and the "surplus power distribution".

[0008] On the other hand, the power conditioner of Patent Document 1 needs to be pre-equipped with a "surplus power distribution mechanism" as its internal circuit, and there is a problem that it cannot be flexibly applied to a power generation mechanism where a normal power conditioner (one in which the addition of a surplus power distribution mechanism is not considered) is already installed.

[0009] Therefore, the inventor has considered a technique of inserting a circuit between the power generation system and the power conditioner to distribute the surplus power.

[0010] In this case, the power conditioner performs "maximum power point control" via the "surplus power distribution" between it and the power generation system. Therefore, there is a problem that the "surplus power distribution" circuitously interferes with the "maximum power point control", and the maximum power point control cannot be achieved on the power conditioner side.

[0011] Therefore, an object of the present invention is to provide a technique for establishing maximum power point control in a power conditioner while distributing surplus power intervening between a power generation system and the power conditioner.

Means for Solving the Problems

[0012] The present invention is a power distribution circuit arranged in the power grid between a "power generation system that generates power" and a "power conditioner that takes in power from the power generation system by maximum power point control and sends it to the main supply destination", and includes the following configurations (branch connection part, distribution power switch part, distribution power receiving part, and pulsation suppression part).

[0013] The branching connection part branches the power generation line (hereinafter referred to as the "power generation line") of the power generation system into a main line leading to the power conditioner and other distribution lines.

[0014] The distribution power switch part intermittently switches the distribution line to extract the distribution power.

[0015] The distribution power receiving part takes in the distribution power and sends it to the distribution power supply destination. The pulsation suppression part suppresses the pulsating voltage applied to the power generation system due to power distribution while passing the voltage change caused by the maximum power point control through the power generation line.

[0016] With the above configuration, the power distribution circuit causes the power conditioner to transmit the increase and decrease control of the received voltage to the power generation system via the pulsation suppression part, and induces the increase and decrease change of the generated current in the power generation system, thereby mediating the maximum power point control (the control to maximize the received power by changing the received voltage) in the power conditioner.

Advantages of the Invention

[0017] According to the above-described solution, in the present invention, while distributing surplus power intervening between the power generation system and the power conditioner, the maximum power point control in the power conditioner can be established mediately.

[0018] Details of problems, configurations, and effects other than those described above will be described in the embodiments described later.

Brief Description of the Drawings

[0019]

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DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

EXAMPLE

[0021] 《Functional Block Diagram of Example 1》 First, Example 1 will be described according to functions. FIG. 1 is a diagram illustrating the functions of Example 1 in blocks. In FIG. 1, the surplus power utilization system D includes a power generation system 100, a power conditioner 200, and a power distribution circuit 300.

[0022] The power generation system 100 converts energy such as sunlight into electric power to generate electricity. Here, the power generation system 100 may be a power generation mechanism that is a control target of maximum power point control, and the type of energy to be converted does not matter.

[0023] The power conditioner 200 takes in the power of the power generation system 100 by maximum power point control and sends it to the main supply destination.

[0024] The power distribution circuit 300 is arranged in the power grid between the power generation system 100 and the power conditioner 200. This power distribution circuit 300 includes a branch connection part 310, a distributed power switch part 320, a distributed power receiving part 330, a pulsation suppression part 340, a main current smoothing part 350, and a distribution control part 360.

[0025] Among these, the branch connection part 310 branches the power generation line Wo of the generated power from the power generation system 100 into a main line Wa toward the power conditioner 200 and other distribution lines Wx.

[0026] The distributed power switch part 320 extracts the distributed power Px by intermittently switching the branched distribution lines Wx.

[0027] The distributed power receiving part 330 takes in the distributed power Px and sends it to the distributed supply destination (such as a power storage system, a hydrogen conversion system, another grid, etc.).

[0028] Note that when the distributed supply destination allows pulse power supply, it is preferable that this distributed power receiving part 330 includes a pulse power supply part 334 that sends the pulsed distributed power Px interrupted in the distributed power switch part 320 to the distributed supply destination.

[0029] The pulsation suppression unit 340 acts on the power generation line Wo that exits the power generation system 100. By suppressing the pulsating voltage applied to the power generation terminals of the power generation system 100, the pulsation suppression unit 340 conveys to the power generation system 100 the increase / decrease control of the received power voltage Va by the power conditioner 200, and induces an increase / decrease change in the power generation current Io in the power generation system 100.

[0030] Therefore, the characteristics of the pulsation suppression unit 340 are preferably set to suppress relatively high-frequency pulsating voltages (such as switching steps and switching noises) that repeat with power sharing while passing through relatively low-frequency voltage changes caused by the increase / decrease control of the received power voltage Va by the power conditioner 200.

[0031] The main current smoothing unit 350 acts on the main line Wa branched at the branch connection unit 310. By suppressing the pulsating current of the received power current Ia that enters the power conditioner 200, the main current smoothing unit 350 conveys to the power conditioner 200 the increase / decrease change (before branching) of the power generation current Io induced in the power generation system 100 due to the maximum power point control as the increase / decrease change (after branching) of the received power current Ia, and enables the maximum power point control in the power conditioner 200.

[0032] Therefore, the characteristics of the main current smoothing unit 350 are preferably set to suppress relatively high-frequency pulsating currents (such as switching steps and switching noises) that repeat with power sharing while passing through relatively low-frequency current changes caused by the increase / decrease change of the power generation current Io of the power generation system 100 in the maximum power point control.

[0033] Note that the power conditioner 200 may originally have a function or circuit corresponding to the main current smoothing unit 350 for noise removal and operation stabilization. In such a case, the main current smoothing unit 350 can also be omitted from the power sharing circuit 300. Therefore, the main current smoothing unit 350 is not an essential component as the power sharing circuit 300.

[0034] The power distribution control unit 360 acquires information regarding the amount of power that is necessary or unnecessary for the main supply destination among the power generation amounts of the power generation system 100 (hereinafter referred to as "power distribution information"). For example, this power distribution information may be rule information preset according to date and time, season, power generation amount, power supply and demand prediction, etc. Also for example, the power distribution information may be information received at any time from the main supply destination (including the command system of the main supply destination, etc.) according to the power supply and demand situation, date and time, season, power generation amount, etc.

[0035] The power distribution control unit 360 controls the power distribution power switch unit 320 according to this power distribution information, and extracts surplus power unnecessary for the main supply destination as the power distribution power Px from between the power generation system 100 and the power conditioner 200.

[0036] Also, the power distribution control unit 360 of the first embodiment restricts the duty ratio of the pulse control of the power distribution power switch unit 320 to "below the upper limit setting where no power loss occurs" according to the power distribution information and performs PWM control.

[0037] <<Circuit Example of the First Embodiment>> Next, a circuit example of the power distribution circuit 300 in the first embodiment will be described. FIG. 2 is a diagram showing a circuit example of the power distribution circuit 300 in the first embodiment. Here, since the power generation system 100 sends out the necessary power generation amount to the main supply destination even at low illuminance, a plurality of solar panels 100a are connected in series and in parallel by a predetermined number. Therefore, surplus power (excess power) that is unnecessary to be sent to the main supply destination is generated in the power generation system 100 at high illuminance or when the power demand of the main supply destination decreases.

[0038] The pulsation suppression unit 340 inserted into the power generation line Wo of the power generation system 100 is composed of a low-pass filter including an inductor L3 of 330 μH and a capacitor C4 of 39 μF. The inductor L3 is inserted in series with the power generation line Wo. The capacitor C4 is bypass-connected between the terminal on the branch connection part 310 side of the inductor L3 and the ground. The frequency characteristics of this pulsation suppression unit 340 suppress the frequency band of power pulsation (switching control) while passing through the frequency band of the maximum power point control by the power conditioner 200.

[0039] The branch connection part 310 is a branch node that divides the power generation line Wo that has exited the pulsation suppression unit 340 into a main line Wa and a distribution line Wx.

[0040] The main current smoothing unit 350 is inserted into the main line Wa after branching. The main current smoothing unit 350 includes a low-pass filter including an inductor L1 of 330 μH and a capacitor C1 of 39 μF. The inductor L1 is inserted in series with the main line Wa. The capacitor C1 is bypass-connected between the terminal on the branch connection part 310 side of the inductor L1 and the ground. The frequency characteristics of this main current smoothing unit 350 suppress the frequency band of power pulsation (switching control) while passing through the frequency band of the maximum power point control by the power conditioner 200.

[0041] On the output side of this main current smoothing unit 350, a main line monitor unit 360a (a part of the distribution control unit 360) is provided as a sensor for current, voltage, power, etc., and detects the received current Ia, received voltage Va, received power Pa, etc. of the input end of the power conditioner 200 (equivalent input load Z1 shown in FIG. 2).

[0042] The distribution power switch unit 320 includes a switching element SW1 inserted into the distribution line Wx after branching. A control signal is input from the distribution control unit 360 to the control terminal ct1 for ON / OFF control of the switching element SW1. The basic frequency of this control signal is preferably set to be separated from the frequency band of the maximum power point control by the power conditioner 200 to such an extent that they can be frequency-separated, for example, 100 kHz.

[0043] The power distribution receiving unit 330 includes a power distribution current smoothing unit 331, a step-up / down circuit 333, and a pulse power supply unit 334 as a configuration for receiving the power distribution power Px and sending it to the power distribution supply destination.

[0044] Among these, the power distribution current smoothing unit 331 includes a low-pass filter composed of an inductor L2 of 330 μH and a capacitor C2 of 39 μF, and a diode D2 for continuously flowing the current of the inductor L2 when the power distribution power switch unit 320 is turned off. The inductor L2 is inserted in series with the power distribution line Wx after switching. The capacitor C2 is bypass-connected between the terminal on the output side (the step-up / down circuit 333 side) of the inductor L2 and the ground. The cathode of the diode D2 is connected to the terminal of the inductor L2 on the power distribution power switch unit 320 side, and the anode of the diode D2 is connected to the ground.

[0045] On the output side of this power distribution current smoothing unit 331, a power distribution line monitor unit 360b (a part of the power distribution control unit 360) is provided as a sensor for current, voltage, power, etc., to detect the power distribution current Ix, power distribution voltage Vx, power distribution power Px, etc. input to the input end of the step-up / down circuit 333 (the equivalent input load Z2 shown in FIG. 2).

[0046] The step-up / down circuit 333 steps up and down the power smoothed by the power distribution current smoothing unit 331 to a voltage suitable for the power distribution supply destination (such as a power storage system, a hydrogen conversion system, or another system). Further, the step-up / down circuit 333 converts the power distribution power Px into alternating current (such as single-phase alternating current or three-phase alternating current) and outputs it to the power distribution supply destination if necessary.

[0047] The equivalent input load Z2 of this step-up / down circuit 333 can be increased or decreased by controlling the internal operation (such as duty ratio, frequency, step-up / down ratio, etc.) of the step-up / down circuit 333.

[0048] The pulse power supply unit 334 branches from the input stage of the power distribution current smoothing unit 331, takes in the pulsed power distribution power Px, and sends it to the power distribution supply destination where pulse power supply is possible.

[0049] The power distribution control unit 360 acquires power distribution information from a preset rule or a main supplier (including the command system of the main supplier). The power distribution control unit 360 performs switching control of the power distribution power switch unit 320 according to this power distribution information so that the detection result of the main line Wa (main line monitor unit 360a) and the detection result of the power distribution line Wx (power distribution line monitor unit 360b) approach the target value of power distribution.

[0050] 《Operation of the pulsation suppression unit 340 in Embodiment 1》 Subsequently, the circuit operation of the pulsation suppression unit 340 in Embodiment 1 will be described. FIG. 3 shows the results of a circuit simulator (SPICE) of the circuit operation of the pulsation suppression unit 340 in Embodiment 1. Here, the duty ratio of the power distribution line Wx (ON period of the power distribution power switch unit 320) is set to 50%.

[0051] FIG. 3[A] is a waveform of the power generation voltage Vo (terminal voltage of the power generation terminal) of the power generation system 100 when the pulsation suppression unit 340 is not inserted into the power generation line Wo. In this case, an increased current supply to the power distribution line Wx during the ON period of the power distribution power switch unit 320 is intermittently supplied from the power generation system 100. Therefore, due to the voltage drop effect of the internal load of the power generation system 100, the power generation voltage Vo of the power generation system 100 drops intermittently during the ON period of the power distribution power switch unit 320. As a result, in the simulation result of FIG. 3[A], a pulsating voltage with a voltage width of 45V - 75V is generated according to the switching frequency of the power distribution power switch unit 320 (here, the fundamental frequency is 100 kHz).

[0052] In a state where the pulsating voltage as shown in FIG. 3[A] is repeatedly generated, the relatively low-frequency increase and decrease changes of the power reception voltage Va in the maximum power point control of the power conditioner 200 are not sufficiently transmitted to the power generation system 100 due to being mixed with the pulsating voltage, and the increase and decrease effect of the power generation current Io required for the maximum power point control is not appropriately induced in the power generation system 100. As a result, the maximum power point control in the power conditioner 200 fails to hold.

[0053] On the other hand, FIG. 3[B] shows the waveform of the generated voltage Vo of the power generation system 100 when the pulsation suppression unit 340 is inserted into the power generation line Wo. In this case, the current intermittently supplied to the distribution line Wx during the ON period of the distribution power switch unit 320 does not pass through the inductor L3 (power generation line Wo), but instantaneously passes through the bypass path (capacitor C4) in the pulsation suppression unit 340.

[0054] For the amount that this bypass current is instantaneously supplied from the capacitor C4, the terminal voltage of the capacitor C4 temporarily decreases. However, this temporary voltage drop is recovered by the DC current supplied from the power generation system 100 via the inductor L3 during the next OFF period of the distribution power switch unit 320. As a result, in the simulation result of FIG. 3[B], the generated voltage Vo of the power generation system 100 generally converges to a DC voltage of about 65V, and the pulsating voltage superimposed on the power generation line Wo is suppressed.

[0055] In the state where the pulsating voltage is suppressed as shown in FIG. 3[B], the relatively low-frequency increase and decrease changes in the received voltage Va in the maximum power point control of the power conditioner 200 are transmitted to the power generation system 100. As a result, the increase and decrease effect of the generated current Io required for the maximum power point control is induced in the power generation system 100. As a result, the maximum power point control in the power conditioner 200 is established.

[0056] 《Circuit Operation of the Main Current Smoothing Unit 350 in Embodiment 1》 Subsequently, the circuit operation of the main current smoothing unit 350 will be described. FIG. 4 shows the result of a circuit simulator (SPICE) showing the circuit operation of the main current smoothing unit 350 of Embodiment 1. Here, the duty ratio of the distribution line Wx (during the ON period of the distribution power switch unit 320) is set to 50%.

[0057] FIG. 4[A] shows the waveform of the received current Ia of the power conditioner 200 when the main current smoothing unit 350 is not inserted into the main line Wa. In this case, only the current amount diverted to the distribution line Wx during the ON period of the distribution power switch unit 320 causes the received current Ia of the power conditioner 200 to intermittently decrease. As a result, in the simulation result of FIG. 4[A], a pulsating current with a current width of 36.6A - 37.3A is generated according to the switching frequency (here, the fundamental frequency is 100 kHz) of the distribution power switch unit 320.

[0058] As shown in FIG. 4[A], in a state where the pulsating current repeatedly occurs, the relatively low-frequency increase and decrease changes in the generated current Io of the power generation system 100 in the maximum power point control are not appropriately transmitted to the power conditioner 200 due to being mixed with the pulsating current. As a result, the maximum power point control in the power conditioner 200 fails to hold.

[0059] On the other hand, FIG. 4[B] shows the waveform of the received current Ia of the power conditioner 200 when the main current smoothing unit 350 is inserted into the main line Wa. In this case, the inductor L1 of the main current smoothing unit 350 acts to maintain the received current Ia flowing through the main line Wa. Therefore, the pulsating current amount that temporarily flows through the distribution line Wx during the ON period of the distribution power switch unit 320 is instantaneously supplied via the bypass path (capacitor C1) of the main current smoothing unit 350.

[0060] To the extent that the current is supplemented from the capacitor C1 in this way, the terminal voltage of the capacitor C1 temporarily decreases. However, the temporarily decreased voltage is instantaneously recovered by the direct current flowing from the power generation system 100 during the next OFF period of the distribution power switch unit 320. As a result, in the simulation result of FIG. 4[B], the received current Ia of the power conditioner 200 converges to approximately a direct current of 36.9A, and the pulsating current superimposed on the direct current is suppressed.

[0061] As shown in FIG. 4[B], in a state where the pulsating current is suppressed, the increase and decrease changes of the generated current Io of the power generation system 100 required for the maximum power point control are transmitted to the power conditioner 200 as relatively low-frequency increase and decrease changes of the received current Ia after branching. As a result, the maximum power point control in the power conditioner 200 is enabled.

[0062] 《Regarding the establishment of maximum power point control in Embodiment 1》 Next, the establishment of the maximum power point control through the mediation of the power distribution circuit 300 will be described. FIG. 5 shows the results of a circuit simulator (SPICE) showing the relationship between the received voltage Va and the received power Pa of the main line Wa in Embodiment 1.

[0063] As shown in FIG. 5, regardless of the switching with the duty ratio of the power distribution power switch section 320 changed, the relationship between the received voltage Va and the received power Pa in the main line Wa shows a unimodal curve characteristic.

[0064] The reason why the relationship between the received voltage Va and the received power Pa maintains the unimodal curve characteristic is that the increase and decrease control of the received voltage Va controlled by the power conditioner 200 through the pulsation suppression unit 340 is transmitted to the power generation system 100, and the increase and decrease changes of the generated current induced in the power generation system 100 are branched and transmitted to the power conditioner 200 through the main current smoothing unit 350 (or an equivalent function on the power conditioner 200 side).

[0065] By maintaining the unimodal curve characteristic in this way, regardless of the duty ratio of the power distribution line Wx, the maximum power point control for the main line Wa (the maximization control to reach the unimodal peak of the received power Pa by changing the received voltage Va) is established.

[0066] 《Regarding the limitation of the duty ratio in Embodiment 1》 Next, the duty ratio limit for avoiding power loss in the power generation system 100 will be described. Here, the total power of each line Wa and Wx is assumed to be DC power and the power factor is 1, and it will be described by simple addition (Pa + Px). However, when AC power is included in the actual system design, the power factor shall be considered.

[0067] FIG. 6 shows the received power Pa of the main line Wa, the distributed power Px of the distribution line Wx, and the total power (Pa + Px) of each line Wa and Wx, which are the results of a circuit simulator (SPICE) shown for each duty ratio of the distribution line Wx (distribution power switch section 320).

[0068] On the other hand, FIG. 7 shows the received current Ia of the main line Wa, the distributed current Ix of the distribution line Wx, and the total power (Pa + Px) of each line Wa and Wx, which are the results of a circuit simulator (SPICE) shown for each duty ratio of the distribution line Wx (distribution power switch section 320).

[0069] In FIGS. 6 and 7, in the range of the duty ratio from 0 to 60%, the total power of each line Wa and Wx is substantially constant. This state may be considered that the maximum power is being drawn from the power generation system 100 by the maximum power point control of the power conditioner 200. That is, in the range of the duty ratio from 0 to 60%, no power loss is observed in the power generation system 100.

[0070] On the other hand, when exceeding the upper limit of that range (for example, 60%) and reaching a duty ratio of 80%, the total power of each line Wa and Wx decreases. This decrease in the total power indicates that the maximum power cannot be drawn from the power generation system 100 even though the maximum power point control of the power conditioner 200 is established. That is, at a duty ratio of 80%, power loss occurs in the power generation system 100.

[0071] Such a power loss phenomenon is considered to be due to the duty ratio of the power distribution switch unit 320 becoming excessive, resulting in a deviation between the "maximum power point on the main line Wa (as seen from the power conditioner 200)" and the "maximum power point of the power generation system 100" exceeding the allowable range.

[0072] In such a case, it is preferable that the power distribution control unit 360 restricts the duty ratio of the power distribution switch unit 320 to "below the upper limit setting where no power loss occurs (here, 60%)" and performs PWM control. As a result, the duty ratio does not become excessive beyond the upper limit, and the power loss of the power generation system 100 is suppressed.

[0073] 《Operation of the Power Distribution Control Unit 360 in Embodiment 1》 Subsequently, the operation of the power distribution control unit 360 will be described. FIG. 8 is a flowchart illustrating the operation of the power distribution control unit 360 in Embodiment 1. Hereinafter, the description will be given in the order of the step numbers shown in FIG. 8.

[0074] Step S101: The power distribution control unit 360 acquires power distribution information regarding the amount of power required (or unnecessary) for the main supply destination within the power generation amount of the power generation system 100.

[0075] Step S102: The power distribution control unit 360 sets a target value for the main power amount to be transmitted to the main supply destination so as not to exceed the upper limit of the duty ratio set in the previous step S106 according to the power distribution information.

[0076] Step S103: The power distribution control unit 360 performs PWM control of the power distribution switch unit 320 so that the detected value of the main power amount by the main line monitor unit 360a matches the target value.

[0077] Step S104: The power distribution control unit 360 acquires the detection signals of the main line monitor unit 360a and the power distribution line monitor unit 360b and determines the presence or absence of power loss.

[0078] As a process for determining the presence or absence of power loss here, for example, any one of (Determination 1) to (Determination 3) is preferable.

[0079] (Determination 1) First, the distribution control unit 360 determines whether the total of the power detection values of the main line monitor unit 360a and the distribution line monitor unit 360b increases by temporarily decreasing the duty ratio of the distribution power switch unit 320. As shown in FIGS. 6 and 7, if the total of the power detection values of the respective lines Wa and Wx remains substantially constant even when the duty ratio decreases, the distribution control unit 360 can determine that "no power loss has occurred". On the other hand, when the total of the power detection values of the respective lines Wa and Wx increases beyond the allowable range due to the temporary decrease in the duty ratio, the distribution control unit 360 can determine that "(before the decrease in the duty ratio) power loss has occurred". After such Determination 1, the distribution control unit 360 returns the temporarily decreased duty ratio to its original value.

[0080] (Determination 2) As shown in the hatched area of FIG. 6, in a situation where power loss occurs, the received power Pa of the main line Wa and the distribution power Px of the distribution line Wx approach each other. Therefore, the distribution control unit 360 detects whether the "power detection value of the main line monitor unit 360a" and the "power detection value of the distribution line monitor unit 360b" are close to each other. When both power detection values are separated by more than the allowable range, the distribution control unit 360 can estimate that "no power loss has occurred". On the other hand, when both power detection values are close to each other within the allowable range, the distribution control unit 360 can estimate that "power loss has occurred".

[0081] (Determination 3) As shown in the hatched area of FIG. 7, in a situation where power loss occurs, the distribution current Ix of the distribution line Wx reverses exceeding the received current Ia of the main line Wa. Therefore, the distribution control unit 360 detects whether the "current detection value of the main line monitor unit 360a" and the "current detection value of the distribution line monitor unit 360b" reverse. When both current detection values do not reverse, the distribution control unit 360 can estimate that "no power loss has occurred". On the other hand, when both current detection values reverse, the distribution control unit 360 can estimate that "power loss has occurred".

[0082] Step S105: If there is no power loss in the determination of step S104, the distribution control unit 360 proceeds to step S110. On the other hand, if there is a power loss, the distribution control unit 360 proceeds to step S106.

[0083] Step S106: The reason for the power loss in the total power is that the duty ratio of the PWM control of the distribution power switch unit 320 is too large. Therefore, the distribution control unit 360 performs a reset to gradually lower the upper limit of the duty ratio by a predetermined width, and returns the operation to step S102. By repeating the conditional branch of steps S104 to S106 until no power loss occurs, the upper limit of the duty ratio converges to an appropriate value. As a result, the duty ratio of the pulse control of the distribution power switch unit 320 is limited to "below the upper limit setting where power loss hardly occurs".

[0084] Note that the conditional branch of steps S104 to S106 only acts in the direction of lowering the "upper limit setting where no power loss occurs". As it is, it cannot adapt to an increase in the power generation capacity of the power generation system 100 due to an increase in the amount of sunlight or the like.

[0085] Therefore, the distribution control unit 360 may perform a reset process of raising the "upper limit setting where no power loss occurs" to the initial value (the value in a situation where the power generation capacity is high) every period (such as a predetermined time) estimated to change the upper limit setting. By repeating the conditional branch of steps S104 to S106 again after this reset process, the "upper limit setting where no power loss occurs" can be raised in adaptation to the increase in the power generation capacity.

[0086] Further, the distribution control unit 360 may gradually increase the duty ratio to obtain the upper limit where the sum of the power detection values of each line Wa and Wx does not decrease, and reset it to the "upper limit setting where no power loss occurs". By this process as well, the "upper limit setting where no power loss occurs" can be raised in adaptation to the increase in the power generation capacity.

[0087] Step S110: The power distribution receiving unit 330 takes in, as the distributed power Px, the surplus power that is unnecessary for the main supply destination among the power generation amounts of the power generation system 100. The power distribution receiving unit 330 smooths the current of the taken-in distributed power Px via the distributed current smoothing unit 331. Further, the power distribution receiving unit 330 boosts or buck-boosts the voltage to the voltage required by the distributed supply destination via the buck-boost circuit 333. Also, if necessary, the buck-boost circuit 333 converts it to an alternating current (such as three-phase alternating current or single-phase alternating current) that matches the distributed supply destination. The power distribution receiving unit 330 sends out the thus processed distributed power Px to the distributed supply destination (such as a power storage system, a hydrogen conversion system, or another system).

[0088] Step S111: The power distribution receiving unit 330 (pulse power supply unit 334) determines whether the distributed supply destination is one to which pulse power supply is possible (for example, a rechargeable battery that can be pulse-charged or pulse-refreshed) by checking the ID information of the distributed supply destination. The power distribution receiving unit 330 (pulse power supply unit 334) sends out the pulsed distributed power Px interrupted at the power distribution power switch unit 320 to the distributed supply destination to which pulse power supply is possible. If possible, the switching frequency of the power distribution (power distribution power switch unit 320) may be set in accordance with the fundamental frequency of the pulse power supply here.

[0089] By repeatedly performing the control operations of Steps S101 to S111 described above by the power distribution control unit 360, an operation is realized in which surplus power that is unnecessary for the main supply destination is taken out as the distributed power Px from between the power generation system 100 and the power conditioner 200 and sent to the distributed supply destination, while mediating the maximum power point control in the power conditioner 200 to be established.

[0090] 《Effect of Example 1》 Hereinafter, the effects exhibited by Example 1 will be described.

[0091] (1) In Example 1, surplus power is extracted as distributed power Px from the power grid between the power generation system 100 and the power conditioner 200 by intermittently switching the distributed line Wx branched via the branch connection part 310 by the distributed power switch part 320. Therefore, in Example 1, it is not necessary for the power conditioner 200 to newly include a "surplus power distribution mechanism". As a result, Example 1 is excellent in that a surplus power distribution mechanism (such as the power distribution circuit 300) can be flexibly added later even in a power generation mechanism where a normal power conditioner 200 is already installed.

[0092] (2) In Example 1, the pulsation suppression part 340 acts on the power generation line Wo. This pulsation suppression part 340 suppresses the pulsating voltage applied to the power generation system 100 due to the power distribution of the distributed power switch part 320 while passing through the change in the received voltage Va caused by the maximum power point control of the power conditioner 200. Therefore, the increase and decrease change in the received voltage Va in the maximum power point control of the power conditioner 200 is transmitted to the power generation system 100, and the increase and decrease change in the generated current Io necessary for the maximum power point control in the power generation system 100 is appropriately induced. Therefore, Example 1 is excellent in that it mediates the establishment of the maximum power point control of the power conditioner 200 by correctly inducing the increase and decrease change in the generated current Io in the maximum power point control.

[0093] (3) Thus, the pulsation suppression part 340 suppresses the pulsating voltage applied to the power generation system 100. As a result, the pulsating current caused by the power distribution does not flow backward into the power generation system 100. Therefore, Example 1 is excellent in that the pulsating current caused by the power distribution hardly flows backward into the power generation system 100, and the internal stress of the power generation system 100 can be reduced.

[0094] (4) In Embodiment 1, the main current smoothing unit 350 (or an equivalent function on the power conditioner 200 side) acts on the main line Wa. This main current smoothing unit 350 smooths the pulsating current entering the power conditioner 200 due to the power distribution of the power distribution power switch unit 320 while passing through the change in the received current Ia caused by the maximum power point control of the power conditioner 200. Therefore, Embodiment 1 is excellent in that it can correctly receive the change in the received current Ia in the maximum power point control and mediately establish the maximum power point control of the power conditioner 200.

[0095] (5) Embodiment 1 includes a power distribution control unit 360 that controls the power distribution power switch unit 320. This power distribution control unit 360 restricts the duty ratio of the pulse control of the power distribution power switch unit 320 to "below the upper limit setting where no power loss occurs". Therefore, Embodiment 1 is excellent in that it can avoid a situation where the duty ratio becomes excessive and power loss occurs.

[0096] (6) By including the pulse power supply unit 334, Embodiment 1 sends the intermittent pulse-shaped power distribution power Px in the power distribution power switch unit 320 to the power distribution destination when the power distribution destination is pulse-power supply enabled. Therefore, Embodiment 1 is excellent in that the pulse power supply unit 334 can perform pulse charging (including refresh charging) on a battery capable of pulse power supply.

Embodiment

[0097] Subsequently, another Embodiment 2 of the present invention will be described.

[0098] 《Functional Block Diagram of Embodiment 2》 First, Embodiment 2 will be described by function. FIG. 9 is a diagram illustrating the functions of Embodiment 2 by block. In FIG. 9, the feature of Embodiment 2 is that the function blocks of the main power switch unit 410 and the current matching unit 420 are newly added to the function block of Embodiment 1 (see FIG. 1).

[0099] The main power switch unit 410 is inserted into the main line Wa between the branch connection unit 310 and the main current smoothing unit 350. The main power switch unit 410 intermittently switches the main line Wa by pulse control with an ON period shifted from that of the power distribution switch unit 320. In other words, by the power distribution control unit 360, both the main power switch unit 410 and the power distribution switch unit 320 perform complementary switching such that during the OFF duty period of the other party, an ON duty period is inserted according to the power distribution information.

[0100] The current matching unit 420 matches the current of the power distribution line Wx to the main line Wa following the increase and decrease changes in the received current Ia of the main line Wa due to the maximum power point control.

[0101] In such Example 2, the pulsation suppression unit 340 suppresses the pulsating voltage acting on the power generation system 100 due to the power distribution of the main power switch unit 410 and the power distribution switch unit 320. Therefore, the pulsation suppression unit 340 conveys the increase and decrease control of the received voltage Va by the power conditioner 200 to the power generation system 100, and induces the increase and decrease changes in the generated current Io in the power generation system 100.

[0102] Also, the main current smoothing unit 350 (or an equivalent function on the power conditioner 200 side) smooths the pulsating current entering the power conditioner 200 due to the power distribution of the main power switch unit 410 and the power distribution switch unit 320. Therefore, the main current smoothing unit 350 conveys the increase and decrease changes in the generated current Io induced in the power generation system 100 to the power conditioner 200 as the increase and decrease changes in the received current Ia branched to the main line Wa.

[0103] With such a function, Example 2 mediately enables the maximum power point control (control to maximize the received power Pa by changing the received voltage Va) in the power conditioner 200.

[0104] Note that since the other functional blocks are the same as those in Example 1, duplicate explanations are omitted here.

[0105] Circuit Example of Example 2 Next, a circuit example of the power distribution circuit 300 in Example 2 will be described. FIG. 10 is a diagram showing a circuit example of the power distribution circuit 300 in Example 2. Here, in order to send out the required power generation amount to the main power supply destination even in low illumination, the power generation system 100 is configured by connecting a predetermined number of a plurality of solar panels 100a in series and in parallel. Therefore, surplus power (excess power) that is not required to be sent to the main power supply destination is generated in the power generation system 100 during high illumination or when the power demand decreases.

[0106] The pulsation suppression unit 340 inserted in the power generation line Wo of the power generation system 100 is composed of a low-pass filter including an inductor L13 of 330 μH and a capacitor C14 of 39 μF. The inductor L13 is inserted in series with the power generation line Wo. The capacitor C14 is bypass-connected between the terminal on the branch connection part 310 side of the inductor L13 and the ground. The frequency characteristics of this pulsation suppression unit 340 suppress the frequency band of power distribution (switching control) while passing through the frequency band of the maximum power point control by the power conditioner 200.

[0107] The branch connection part 310 is a branch node that divides the power generation line Wo that has exited the pulsation suppression unit 340 into a main line Wa and a distribution line Wx.

[0108] The main power switch unit 410 includes a switching element SW12 inserted in the main line Wa after branching. A control signal is input to the control terminal ct12 for pulse control of the switching element SW12 from the distribution control unit 360. This control signal has an ON period shifted from the control signal of the distribution power switch unit 320. It is preferable to set the basic frequency of this control signal to be separated from the frequency band of the maximum power point control by the power conditioner 200 to such an extent that they can be frequency-separated, for example, 100 kHz.

[0109] The main current smoothing unit 350 is inserted into the main line Wa between the main power switch unit 410 and the power conditioner 200. The main current smoothing unit 350 includes a low-pass filter composed of an inductor L11 of 330 μH and a capacitor C11 of 39 μF. The inductor L11 is inserted in series with the main line Wa. The capacitor C11 is bypass-connected between the terminal of the inductor L11 on the power conditioner 200 side and the ground. The frequency characteristics of this main current smoothing unit 350 suppress the frequency band of the power sharing (switching control) while passing through the frequency band of the maximum power point control by the power conditioner 200.

[0110] Furthermore, the main current smoothing unit 350 includes a diode D11 for continuously flowing the current of the inductor L11 when the main power switch unit 410 is turned off. The cathode of the diode D11 is connected to the terminal of the inductor L11 on the main power switch unit 410 side, and the anode of the diode D11 is connected to the ground.

[0111] On the output side of this main current smoothing unit 350, a main line monitor unit 360a (a part of the power sharing control unit 360) is provided as a sensor for current, voltage, power, etc., and detects the received current Ia, received voltage Va, received power Pa, etc. of the input end (equivalent input load Z11 shown in FIG. 10) of the power conditioner 200.

[0112] The power sharing power switch unit 320 is inserted into the branched power sharing line Wx. The power sharing power switch unit 320 includes a switching element SW11. A control signal is input from the power sharing control unit 360 to the control terminal ct11 for pulse control of the switching element SW11. As described above, this control signal is a control signal whose ON period is shifted from the control signal of the main power switch unit 410. It is preferable to set the basic frequency of this control signal to be separated from the frequency band of the maximum power point control by the power conditioner 200 to such an extent that they can be frequency-separated, for example, 100 kHz.

[0113] The power distribution receiving unit 330 includes a power distribution current smoothing unit 331, a step-up / down circuit 333, and a pulse power supply unit 334 as a configuration for receiving the power distribution power Px and sending it to the power distribution supply destination.

[0114] Among these, the power distribution current smoothing unit 331 includes a low-pass filter composed of an inductor L12 of 330 μH and a capacitor C12 of 39 μF, and a diode D12 for continuously flowing the current of the inductor L2 when the power distribution power switch unit 320 is turned off. The inductor L12 is inserted in series with the power distribution line Wx after switching. The capacitor C12 is bypass-connected between the terminal on the output side (the step-up / down circuit 333 side) of the inductor L12 and the ground. The cathode of the diode D12 is connected to the terminal of the inductor L12 on the power distribution power switch unit 320 side, and the anode of the diode D12 is connected to the ground.

[0115] On the output side of this power distribution current smoothing unit 331, a power distribution line monitor unit 360b (a part of the power distribution control unit 360) is provided as a sensor for current, voltage, power, etc., and detects the power distribution current Ix, power distribution voltage Vx, power distribution power Px, etc. input to the input terminal (equivalent input load Z12 shown in FIG. 10) of the step-up / down circuit 333.

[0116] The step-up / down circuit 333 steps up / down the power smoothed by the power distribution current smoothing unit 331 to a voltage suitable for the power distribution supply destination (such as a power storage system, a hydrogen conversion system, or another system), and converts it to alternating current (such as single-phase alternating current or three-phase alternating current) if necessary, and outputs it to the power distribution supply destination.

[0117] The equivalent input load Z12 of this step-up / down circuit 333 can be increased or decreased by controlling the internal operation (such as duty ratio, frequency, step-up / down ratio, etc.) of the step-up / down circuit 333.

[0118] The pulse power supply unit 334 branches from the input stage of the power distribution current smoothing unit 331, takes in the pulsed power distribution power Px, and sends it to the power distribution supply destination where pulse power supply is possible.

[0119] The power distribution control unit 360 acquires power distribution information from preset rules or the main supplier (including the command system of the main supplier). The power distribution control unit 360 controls the main power switch unit 410 and the power distribution power switch unit 320 according to this power distribution information so that the detection result of the main line Wa (main line monitor unit 360a) and the detection result of the power distribution line Wx (power distribution line monitor unit 360b) approach the target value of power distribution.

[0120] The current matching unit 420 controls the boost - buck circuit 333 (input load Z12), etc., following the increase - decrease change of the received current Ia detected by the main line monitor unit 360a (due to the maximum power point control), and matches the power distribution current Ix detected by the power distribution line monitor unit 360b with the received current Ia.

[0121] 《Operation of the pulsation suppression unit 340 in Embodiment 2》 Subsequently, the circuit operation of the pulsation suppression unit 340 in Embodiment 2 will be described. FIG. 11 shows the results of a circuit simulator (SPICE) of the circuit operation of the pulsation suppression unit 340 in Embodiment 2. Here, the duty ratio of the main line Wa (ON period of the main power switch unit 410) is 40%, and the duty ratio of the power distribution line Wx (ON period of the power distribution power switch unit 320) is 60%.

[0122] FIG. 11[A] shows the waveform of the power generation voltage Vo of the power generation system 100 when the pulsation suppression unit 340 is not inserted into the power generation line Wo.

[0123] Here, due to the current matching effect of the current matching unit 420, the step of current mismatch generated in the power generation line Wo due to the power distribution between the main power switch unit 410 and the power distribution power switch unit 320 is suppressed.

[0124] However, in FIG. 11[A], the switching noises of the main power switch unit 410 and the power distribution switch unit 320 remain. Further, in FIG. 11[A], as a transient response of power distribution (switching), a sawtooth-shaped step also remains. Therefore, when the pulsation suppression unit 340 is not inserted, these switching noises and sawtooth steps are repeatedly applied as pulsating voltages to the generated voltage Vo of the power generation system 100.

[0125] In a state where the pulsating voltage as shown in FIG. 11[A] repeatedly occurs, the relatively low-frequency increase and decrease changes of the received voltage Va in the maximum power point control of the power conditioner 200 are not sufficiently transmitted to the power generation system 100 due to being masked by the pulsating voltage, and the increase and decrease effect of the generated current Io required for the maximum power point control is not appropriately induced in the power generation system 100. As a result, the maximum power point control in the power conditioner 200 fails to hold.

[0126] On the other hand, FIG. 11[B] shows the waveform of the generated voltage Vo of the power generation system 100 when the pulsation suppression unit 340 is inserted into the power generation line Wo. In this case, the above-described switching noises and sawtooth steps do not pass through the inductor L13 but instantaneously pass through the bypass path (capacitor C14) in the pulsation suppression unit 340. The terminal voltage of the capacitor C14 temporarily decreases by the amount of the bypass current instantaneously supplied from the capacitor C14. However, the temporarily decreased voltage is restored by the DC current supplied from the power generation system 100 via the inductor L13. As a result, in the simulation result of FIG. 11[B], the generated voltage Vo of the power generation system 100 converges to a DC voltage of about 67V, and the pulsating voltage superimposed on the power generation line Wo is suppressed.

[0127] In a state where the pulsating voltage is suppressed as shown in FIG. 11[B], since the relatively low-frequency increase and decrease changes of the received voltage Va due to the maximum power point control of the power conditioner 200 are transmitted to the power generation system 100, the increase and decrease effect of the generated current Io required for the maximum power point control is induced in the power generation system 100. As a result, the maximum power point control in the power conditioner 200 comes to hold.

[0128] Circuit Operation of the Main Current Smoothing Unit 350 in Embodiment 2 Subsequently, the circuit operation of the main current smoothing unit 350 will be described. FIG. 12 shows the result of a circuit simulator (SPICE) of the circuit operation of the main current smoothing unit 350 in Embodiment 2. Here, the duty ratio of the main line Wa (ON period of the main power switch unit 410) is set to 40%, and the duty ratio of the distribution line Wx (ON period of the distribution power switch unit 320) is set to 60%.

[0129] FIG. 12[A] shows the waveform of the input current of the main current smoothing unit 350. Along with the switching of the main line Wa by the main power switch unit 410, the input current of the main current smoothing unit 350 changes intermittently. As a result, in the simulation result of FIG. 12[A], a pulsating current with a current width of 0 A - 45.9 A is generated according to the switching frequency of the main power switch unit 410 (here, the fundamental frequency is 100 kHz).

[0130] When the main current smoothing unit 350 is not inserted (and when the power conditioner 200 also does not have the same function), this pulsating current is superimposed and input to the power conditioner 200. In this state, the relatively low-frequency increase and decrease changes in the generated current Io of the power generation system 100 in the maximum power point control are not appropriately transmitted to the power conditioner 200 due to being mixed with the pulsating current. As a result, the maximum power point control in the power conditioner 200 fails to hold.

[0131] FIG. 12[B] shows the waveform of the output current of the main current smoothing unit 350. The diode D11 of the pulsation suppression unit 340 supplies a forward current so as to maintain the received current Ia flowing through the inductor L11 during the OFF period of the main power switch unit 410. Further, the capacitor C11 smoothes the remaining pulsating current. As a result, in the simulation result of FIG. 12[B], the received current Ia of the power conditioner 200 converges to a DC current of about 45.7 A, and the pulsating current superimposed on the DC current is suppressed.

[0132] As shown in FIG. 12[B], in the state where the pulsating current is suppressed, the relatively low-frequency increase and decrease changes in the generated current Io of the power generation system 100 in the maximum power point control are transmitted to the power conditioner 200 as the increase and decrease changes in the received current Ia after branching to the main line Wa. As a result, the maximum power point control in the power conditioner 200 is enabled.

[0133] 《Regarding the establishment of the maximum power point control in Embodiment 2》 Next, the establishment of the maximum power point control through the mediation of the power distribution circuit 300 will be further explained.

[0134] FIG. 13 shows the results of a circuit simulator (SPICE) showing the relationship between the received voltage Va and the received power Pa of the main line Wa in Embodiment 2. In each plot in FIG. 13, current matching is performed by the current matching unit 420.

[0135] As shown in FIG. 13, regardless of the switching in which the duty ratio of the main power switch unit 410 is changed from 20% to 100%, the relationship between the received voltage Va and the received power Pa in the main line Wa maintains a unimodal curve characteristic.

[0136] The reason why the relationship between the received voltage Va and the received power Pa maintains a unimodal curve characteristic is that the increase and decrease control of the received voltage Va controlled by the power conditioner 200 through the pulsation suppression unit 340 is transmitted to the power generation system 100, and the increase and decrease changes in the generated current Io attracted to the power generation system 100 are branched and transmitted to the power conditioner 200 through the main current smoothing unit 350 (or an equivalent function on the power conditioner 200 side).

[0137] In this way, by maintaining the unimodal curve characteristic, regardless of the switching of the main power switch unit 410 and the power distribution power switch unit 320, due to the intervention of the power distribution circuit 300, the maximum power point control for the main line Wa (maximization control to reach the unimodal peak of the received power Pa by changing the received voltage Va) is established.

[0138] "Explanation of the Operation of Current Integration Unit 420" Next, the operation of the current integration unit 420 in Embodiment 2 will be described. FIG. 14 shows the results of a circuit simulator (SPICE) of the operation of the current integration unit 420.

[0139] Here, the duty ratio of the main line Wa (ON period of the main power switch unit 410) is set to 20%, and the duty ratio of the distribution line Wx (ON period of the distribution power switch unit 320) is set to 80%.

[0140] Incidentally, in FIG. 14, in order to calculate the basic waveform of the occurrence of current mismatch by circuit calculation, the cut-off frequency of the ripple suppression unit 340 is set high (inductor L13 is 0.01 μH, capacitor C14 is 0.39 μF).

[0141] FIG. 14[A] shows the waveform of the generated current Io of the power generation system 100 when the current integration unit 420 does not perform current integration. Here, a generated current Io of about 46 A flows during the ON period of the main power switch unit 410, and a generated current Io of about 7 A flows during the ON period of the distribution power switch unit 320. Therefore, a current mismatch step with a current amplitude of 7A - 46A occurs repeatedly.

[0142] On the other hand, FIG. 14[B] shows the waveform of the generated current Io of the power generation system 100 when the current integration unit 420 performs current integration. Here, a generated current Io of about 45.4 A flows during the ON period of the main power switch unit 410, and a generated current Io of about 45.4 A flows with current integration during the ON period of the distribution power switch unit 320. Therefore, the current amplitude caused by current mismatch is suppressed.

[0143] Note that even when the current integration unit 420 does not perform current integration, the ripple suppression unit 340 suppresses the frequency band of power distribution, so there is no problem with the maximum power point control for the main line Wa. Therefore, in the establishment of the maximum power point control, the operation of the current integration unit 420 is not an essential requirement.

[0144] "Regarding the Effects of Current Integration of Current Integration Unit 420" Next, the practical effects of the current matching of the current matching unit 420 will be described. Here, the total power of each line Wa and Wx is assumed to be DC power and the power factor is 1, and the explanation will be given by simple addition (Pa + Px). However, when AC power is included in the actual system design, the power factor shall be considered.

[0145] FIG. 15 shows the results of a circuit simulator (SPICE) in which the received power Pa of the main line Wa, the distributed power Px of the distribution line Wx, and the total power (Pa + Px) of each line Wa and Wx are plotted for each current difference between the lines Wa and Wx.

[0146] Here, the duty ratio of the main line Wa (ON period of the main power switch unit 410) is set to 20%, and the duty ratio of the distribution line Wx (ON period of the distribution power switch unit 320) is set to 80%.

[0147] In FIG. 15, it is assumed that while the power conditioner 200 performs maximum power point control on the main line Wa, the input load Z12 of the distribution line Wx is adjusted to increase or decrease the current difference between the lines Wa and Wx, and circuit calculations are performed.

[0148] From the results of FIG. 15 like this, it can be seen that in the state where the current matching of each line Wa and Wx is achieved, the total power (Pa + Px) of each line Wa and Wx becomes maximum.

[0149] Based on this result, it can be said that as the current matching unit 420 performs current matching of each line Wa and Wx following the change in the received current Ia of the main line Wa due to the maximum power point control, the maximum power point control of the power generation system 100 is consequently realized.

[0150] In other words, due to the current matching effect of the current matching unit 420, the current passing through the main power switch unit 410 during the ON period and the current passing through the power distribution power switch unit 320 during the ON period are current-matched and balanced, so that it can be said that the "maximum power point of the main line Wa after branching" and the "maximum power point of the power generation system 100 before branching" can be made to substantially coincide constantly.

[0151] In this way, by the current matching unit 420 making the "maximum power points before and after the branch connection unit 310" substantially coincide, even though the power conditioner 200 performs maximum power point control on the main line Wa after branching, it becomes possible to draw the maximum power from the power generation system 100 before branching.

[0152] According to FIG. 15, it is not necessary for the current matching of the current matching unit 420 to be the current matching point (i.e., only one point) of each line Wa, Wx. For example, a permissible range of current difference (hereinafter referred to as the "current matching range") within which the total power of each line Wa, Wx can be regarded as being maximally practical may be defined. In this case, if the current matching unit 420 performs current matching so that the current difference between each line Wa, Wx falls within the "current matching range", the maximum power point control of the power generation system 100 will be practically realized.

[0153] 《Regarding the Power Efficiency of Power Distribution in Embodiment 2》 Subsequently, the power efficiency for each duty ratio in Embodiment 2 will be described. FIG. 16 shows the results of a circuit simulator (SPICE) in which the received power Pa of the main line Wa, the distributed power Px of the distribution line Wx, and the total power (Pa + Px) of each line Wa, Wx are plotted for each duty ratio of the main line Wa.

[0154] Here, circuit calculations are performed on the assumption that the power conditioner 200 performs maximum power point control on the main line Wa while the current matching unit 420 matches the current of the distribution line Wx to the current of the main line Wa.

[0155] In FIG. 16, as a result of circuit calculations in the range of the duty ratio of the main line Wa from 20% to 100%, the total power (Pa + Px) of each line Wa and Wx became substantially constant. Therefore, in Example 2, almost no power loss occurred as described in Example 1 (see FIGS. 6 and 7). That is, it can be said that in Example 2, efficient power distribution is achieved.

[0156] The phenomenon of such increased efficiency of power distribution can be explained by the phenomenon of "maximizing the total power by current matching in the current matching unit 420" described in FIG. 15. That is, by the current matching unit 420 making the "maximum power points before and after the branch connection unit 310" substantially coincide, the power conditioner 200 can stably draw the maximum power from the power generation system 100 before the branch, even though it is performing maximum power point control on the main line Wa after the branch.

[0157] 《Operation of the Distribution Control Unit 360 in Example 2》 Subsequently, the operation of the distribution control unit 360 will be described. FIG. 17 is a flowchart illustrating the operation of the distribution control unit 360 in Example 2. Hereinafter, the explanation will be given in the order of the step numbers shown in FIG. 17.

[0158] Step S201: The distribution control unit 360 acquires distribution information regarding the amount of power that is necessary or unnecessary for the main supply destination within the power generation amount of the power generation system 100.

[0159] Step S202: The distribution control unit 360 determines the power ratio of the generated power to be sent to the main supply destination according to the distribution information. The distribution control unit 360 performs PWM control of the main power switch unit 410 at a duty ratio corresponding to the power ratio.

[0160] Step S203: The distribution control unit 360 determines the power ratio of the generated power to be sent to the destination of the distributed power Px according to the distribution information. The distribution control unit 360 performs PWM control to turn on the distribution power switch unit 320 at the timing within the OFF duty of the main power switch unit 410 with a duty ratio corresponding to the power ratio.

[0161] Step S204: The current matching unit 420 obtains current difference information regarding the current difference between each line Wa and Wx based on the detection values of the main line monitor unit 360a and the distribution line monitor unit 360b.

[0162] Step S205: The current matching unit 420 controls the distribution voltage Vx of the distribution power receiving unit 330 (step-up / down circuit 333), the input load Z12, etc. according to the current difference information, and matches the distribution current Ix of the distribution line Wx with the received current Ia of the main line Wa.

[0163] Step S206: The distribution power receiving unit 330 transmits the distribution power Px as surplus power unnecessary for the main supply destination to the distribution supply destination (such as a power storage system, a hydrogen conversion system, another system, etc.).

[0164] Step S207: When the distribution supply destination is pulse-power supply enabled, the pulse power supply unit 334 transmits the pulsed distribution power Px. For example, the pulse power supply unit 334 performs pulse charging on a battery that enables pulse charging or pulse refresh charging.

[0165] By repeating the control operations of steps S201 to S207 described above by the distribution control unit 360, while taking out the surplus power unnecessary for the main supply destination from between the power generation system 100 and the power conditioner 200 as the distribution power Px and transmitting it to the distribution supply destination, the operation of mediating the maximum power point control in the power conditioner 200 is realized.

[0166] 《Effect of Embodiment 2》 Embodiment 2 has the same effect as Embodiment 1. Furthermore, Embodiment 2 newly has the following effects.

[0167] (1) In Embodiment 2, switching with a shift in the ON period is performed in the main line Wa and the distribution line Wx. Therefore, Embodiment 2 is excellent in that power distribution between the main line Wa and the distribution line Wx does not interfere as much as the time-division operation of power distribution, and highly independent power distribution is realized between the respective lines Wa and Wx.

[0168] (2) In Embodiment 2, by performing PWM control on the main power switch unit 410 according to the distribution information, the amount of power required by the main supply destination is sent as the main power to the main supply destination. Further, in Embodiment 2, at the timing within the OFF duty of the main power switch unit 410, the distribution power switch unit 320 is turned on according to the distribution information, and surplus power unnecessary for the main supply destination is sent as the distribution power Px to the distribution supply destination. Therefore, Embodiment 2 is excellent in that, according to the distribution information, while sending the amount of power required by the main supply destination to the main supply destination, surplus power unnecessary for the main supply destination can be sent as the distribution power Px to the distribution supply destination.

[0169] (3) In Embodiment 2, the current matching unit 420 matches the current of the distribution line Wx to the main line Wa. By this current matching, the "maximum power point of the main line Wa after branching" and the "maximum power point of the power generation system 100 before branching" substantially coincide. Therefore, Embodiment 2 is excellent in that, although the power conditioner 200 performs maximum power point control on the main line Wa after branching, maximum power can be drawn from the power generation system 100 before branching (see FIGS. 15 and 16).

[0170] (4) In Embodiment 2, by the cooperation of the "current matching of the current matching unit 420" and the "maximum power point control of the power conditioner 200", the total power of each line Wa and Wx can be maximized. Therefore, Embodiment 2 is excellent in that highly power-efficient power distribution is realized (see FIGS. 15 and 16).

Embodiment

[0171] Subsequently, another Embodiment 3 of the present invention will be described.

[0172] "Functional Block Diagram of Example 3" FIG. 18 is a diagram illustrating the functions of the surplus power utilization system D of Example 3 block by block.

[0173] In FIG. 18, the surplus power utilization system D includes a power generation system 100, a power conditioner 200, a power distribution circuit 300, and a time-shifted power supply unit 500.

[0174] In Example 3, the surplus power utilization system D includes the time-shifted power supply unit 500 as at least one of the power distribution destinations of the power distribution circuit 300. The time-shifted power supply unit 500 stores the distributed power Px distributed from the power distribution circuit 300 as surplus power that the main power supply destination does not need at that time. The time-shifted power supply unit 500 sends out the surplus power stored in the past to the main power supply destination with a time shift.

[0175] Note that since other configurations of Example 3 are the same as those of Example 1 and / or Example 2, duplicate explanations are omitted here.

[0176] "Operation of the Time-Shifted Power Supply Unit 500 in Example 3" Subsequently, the operation of the time-shifted power supply unit 500 will be described. FIG. 19 is a flowchart illustrating the operation of the time-shifted power supply unit 500 in Example 3. Hereinafter, the explanation will be given in the order of the step numbers shown in FIG. 19.

[0177] Step S301: The time-shifted power supply unit 500 receives the distributed power Px of the power distribution circuit 300 as surplus power that is not required by the main power supply destination at that time.

[0178] Step S302: The time-shifted power supply unit 500 stores the received surplus power in a power storage destination. Such a power storage destination is not particularly limited as long as it is a power storage mechanism, and for example, a power storage system, a hydrogen conversion system, or an in-vehicle power storage system is preferable.

[0179] Step S303: The time-difference power supply unit 500 acquires distribution information and the like from the main supply destination and detects the power demand situation at the main supply destination.

[0180] Step S304: The time-difference power supply unit 500 communicates with the power distribution circuit 300 (distribution control unit 360) or the like to detect the power supply situation to the main supply destination from the power distribution circuit 300. Note that the time-difference power supply unit 500 may detect (estimate) the power supply situation to the main supply destination by detecting the excess or deficiency of the distributed power Px by the power distribution circuit 300.

[0181] Step S305: The time-difference power supply unit 500 determines the amount of power (time-difference power supply amount) to be supplied to the main supply destination from the surplus power stored in the past (current stored power amount) according to the "power demand of the main supply destination" and the "power supply of the power distribution circuit 300".

[0182] Step S306: The time-difference power supply unit 500 outputs the surplus power stored in the past to the main supply destination with a time shift according to the time-difference power supply amount. As the power supply path to the main supply destination, power may be directly supplied to the main supply destination, or power may be supplied to the main supply destination via the power conditioner 200.

[0183] By repeating the operations of steps S301 to S306, the time-difference power supply unit 500 sends the surplus power to the main supply destination at a timing shifted from the power distribution of the power distribution circuit 300.

[0184] 《Effect of Embodiment 3》 Embodiment 3 has the same effects as Embodiments 1 to 2. Furthermore, Embodiment 3 newly has the following effects.

[0185] (1) In Embodiment 3, the distributed power Px transmitted by the power distribution circuit 300 is stored as surplus power that is not required by the main power supply destination at the current time. The surplus power stored in the past in this way is transmitted to the main power supply destination with a time shift. Therefore, Embodiment 3 is excellent in that it can store surplus power that is not required by the main power supply destination at that time and supply the surplus power to the main power supply destination at a more appropriate timing by transmitting it to the main power supply destination later.

[0186] 《Supplementary Matters of the Embodiment》 In the above-described embodiment, a power company or the like that can sell electricity is assumed as the main power supply destination, and the roles of the distributed power supply destinations that utilize the surplus power are fixedly explained. However, the present invention is not limited to the roles of the main power supply destination and the distributed power supply destination. For example, within the power distribution circuit 300, maximum power point control may be applied with one of the distributed power supply destinations as the main power supply destination, and the others as the distributed power supply destinations, so that the roles of the main power supply destination and the distributed power supply destinations can be exchanged at any time and flexibly.

[0187] Furthermore, in the above-described embodiment, for the sake of simplicity of explanation, the distribution line Wx is described as one line. However, the present invention is not limited to the number of lines of the distribution line Wx. For example, at the branch connection portion 310, it may be multi-branched into the main line Wa leading to the power conditioner 200 and a plurality of distribution lines Wx.

[0188] In particular, in the case of Embodiment 1, it is preferable to perform switching by shifting the ON periods among these plurality of distribution lines Wx. By shifting the ON periods among the plurality of distribution lines Wx in this way, the operation interference among the plurality of distribution lines Wx is reduced.

[0189] In addition, in the case of Example 2, it is preferable to perform switching by shifting the ON periods between the main line Wa and the plurality of distribution lines Wx respectively. By shifting the ON periods between the main line Wa and the plurality of distribution lines Wx in this way, the operation interference between the main line Wa and the plurality of distribution lines Wx is reduced. Further, in Example 2, it is preferable to achieve current matching with the main line Wa for each of these plurality of distribution lines Wx in parallel with the maximum power point control of the power conditioner 200. By such an operation as well, it becomes possible to draw out the maximum power from the power generation system 100 by the cooperation of the maximum power point control for the main line Wa and the current matching of the other plurality of distribution lines Wx.

[0190] Also, in the above-described embodiments, suitable circuit examples (such as FIGS. 2 and 10) have been described. However, the present invention is not limited to the circuits (circuit configurations, circuit connections, circuit sequences, circuit constants, circuit characteristics, etc.) shown in these circuit examples.

[0191] For example, in the above-described circuit example (see FIG. 2), the capacitor C4 arranged on the power generation line Wo and the capacitor C1 arranged on the main line Wa are individually provided. These capacitors C1 and C4 perform overlapping functions in that they instantaneously supply current during the ON period of the distribution power switch section 320. Therefore, either one of these capacitors C1 and C4 may be omitted, or the connection locations of the capacitors C1 and C4 may be moved to the distribution line Wx side.

[0192] Also, for example, in the above-described circuit example (see FIG. 10), the branch connection section 310, the main power switch section 410, and the distribution power switch section 320 have been described as independent configurations. However, the present invention is not limited to such circuits. For example, the branch connection section 310, the main power switch section 410, and the distribution power switch section 320 may be integrally configured and realized by a switching circuit such as a one-circuit multi-contact (selectively switching an input to a plurality of outputs).

[0193] In the above-described embodiments, the operation interference between the maximum power point control and the power sharing is separated by frequency bands. However, the present invention only requires the separation of such operation interference and is not limited to the separation form. For example, the operation interference between the maximum power point control and the power sharing may be separated by differences such as phase, waveform, periodicity, or by a comb filter. Further, the operation interference between the maximum power point control and the power sharing may be separated by performing the maximum power point control and the power sharing in a time division manner.

[0194] In addition, in the above-described embodiments, a circuit example (see FIGS. 2 and 10) in which the main current smoothing unit 350 is provided on the power sharing circuit 300 side has been described. In this circuit example, regardless of whether the power conditioner 200 side has a function equivalent to that of the main current smoothing unit 350, it is always possible to reduce the circuit interference of the power sharing (pulsating current) with respect to the power conditioner 200. However, the present invention is not limited to this. For example, when a function equivalent to that of the main current smoothing unit 350 exists on the power conditioner 200 side, the circuit configuration may be simplified by omitting the main current smoothing unit 350 on the power sharing circuit 300 side.

[0195] In the circuit examples shown in FIGS. 2 and 10, when the main current smoothing unit 350 on the power sharing circuit 300 side is omitted, the detection signals such as voltage, current, and power monitored by the main line monitor unit 360a are affected by the power sharing (pulsating current, etc.). In such a case, it is preferable to provide a filter processing unit that suppresses the signal change caused by the power sharing while passing the signal change caused by the maximum power point control with respect to the detection signal of the main line monitor unit 360a.

[0196] In the circuit example shown in FIG. 10, the current matching unit 420 acquires the current difference information from the main line monitor unit 360a and the sharing line monitor unit 360b, and performs current matching between the main line Wa and the sharing line Wx. However, the present invention is not limited to this.

[0197] For example, the current matching unit 420 may acquire the current difference between the ON current of the main line Wa (main power switch unit 410) and the ON current of the distribution line Wx (distribution power switch unit 320) as current difference information. In this case, the current matching unit 420 controls so as to align the ON current of the distribution line Wx with the ON current of the main line Wa. Even by such control, current matching between the lines Wa and Wx can be achieved.

[0198] Also, for example, the current matching unit 420 may monitor between the pulsation suppression unit 340 and the branch connection unit 310, detect a waveform step repeatedly superimposed on a detected waveform such as current or voltage, and acquire the current step obtained from the waveform step as current difference information. In this case, the current matching unit 420 controls the current on the distribution line Wx side so that the current step is adjusted within the allowable range. Even by such control, current matching between the lines Wa and Wx can be achieved.

[0199] Note that in the above-described embodiment, the operation of performing power distribution between the main line Wa and the distribution line Wx by high-speed switching has been described. However, the present invention is not limited to this.

[0200] For example, when there is no surplus power, the power generation power of the power generation system 100 may be directly sent to the power conditioner 200 (main supply destination) via the power distribution circuit 300 by shutting off the distribution power switch unit 320.

[0201] Also, for example, when power transmission to the main supply destination is unnecessary in the second embodiment, the main power switch unit 410 of the main line Wa may be shut off while the distribution power switch unit 320 of the distribution line Wx is opened. Note that in this situation, since the maximum power point control cannot be performed in the power conditioner 200 where the power supply is cut off, it is preferable that the distribution power receiving unit 330 or the like performs the maximum power point control instead.

[0202] As described above, the present invention is not limited to the contents of the above-described embodiments, and various modifications are possible. In particular, the above-described embodiments have been described in detail in their entirety for the purpose of explaining the present invention clearly, and the present invention is not necessarily limited to those having all the components, configurations, functions, steps, and data structures described. Also, the individual elements of Examples 1 and 2 may be combined as appropriate. Furthermore, it is also possible to add, omit, delete, or replace other configurations and other steps with respect to the embodiments.

Explanation of Reference Numerals

[0203] 100... Power generation system, 100a... Solar panel, 200... Power conditioner, 300... Power distribution circuit, 310... Branch connection part, 320... Power distribution power switch part, 330... Power distribution power receiving part, 331... Power distribution current smoothing part, 333... Step-up / down circuit, 334... Pulse power supply part, 340... Pulsation suppression part, 350... Main current smoothing part, 360... Power distribution control part, 360a... Main line monitor part, 360b... Power distribution line monitor part, 500... Time difference power supply part, 410... Main power switch part, 420... Current matching part, C1... Capacitor, C11... Capacitor, C12... Capacitor, C14... Capacitor, C2... Capacitor, C4... Capacitor, D... Surplus power utilization system, D11... Diode, D12... Diode, D2... Diode, Ia... Received current, Io... Generated current, Ix... Power distribution current, L1... Inductor, L11... Inductor, L12... Inductor, L13... Inductor, L2... Inductor, L3... Inductor, Pa... Received power, Px... Power distribution power, SW1... Switching element, SW11... Switching element, SW12... Switching element, Va... Received voltage, Vo... Generated voltage, Vx... Power distribution voltage, Wa... Main line, Wo... Generated line, Wx... Power distribution line, Z1... Input load, Z11... Input load, Z12... Input load, Z2... Input load, ct1... Control terminal, ct11... Control terminal, ct12... Control terminal

Claims

1. A power distribution circuit that is arranged in a power system between a “power generation system that generates electricity” and a “power conditioner that takes in power from the power generation system by maximum power point control and sends it to a main power supply destination” and performs power distribution, a branch connection section that branches a power generation line (hereinafter referred to as a “generation line”) of the power generation system into a main line leading to the power conditioner and other distribution lines, a distribution power switch section that switches the distribution lines and extracts distribution power, a distribution power receiving section that takes in the distribution power and sends it as surplus power to a distribution power supply destination, and a pulsation suppression section that suppresses pulsating voltage applied to the power generation system due to the power distribution while passing the voltage change caused by the maximum power point control through the generation line, wherein the power conditioner's control of increasing and decreasing the received voltage is transmitted to the power generation system via the pulsation suppression section to induce an increase and decrease change in the generated current in the power generation system, thereby mediating the establishment of the maximum power point control (control for maximizing the received power by changing the received voltage) in the power conditioner characterized by the above power distribution circuit.

2. The power distribution circuit according to claim 1, wherein in the main line branched by the branch connection section, a main power switch section is provided that switches the main line by pulse control with an ON period shifted from that of the distribution power switch section, and the pulsation suppression section suppresses the pulsating voltage applied to the power generation system due to the power distribution by the main power switch section and the distribution power switch section, and transmits the power conditioner's control of increasing and decreasing the received voltage to the power generation system to induce an increase and decrease change in the generated current in the power generation system, thereby mediating the establishment of the maximum power point control (control for maximizing the received power by changing the received voltage) in the power conditioner characterized by the above power distribution circuit.

3. The power distribution circuit according to claim 2, comprising a distribution control section that controls the main power switch section and the distribution power switch section The power distribution control unit acquires information regarding the amount of power that is necessary or unnecessary for the main supply destination among the power generation amounts of the power generation system (hereinafter referred to as "power distribution information"), and controls the duty ratio of the pulse control of the main power switch unit according to the power distribution information to send the amount of power necessary for the main supply destination as main power to the main supply destination, and turns on the power distribution power switch unit according to the power distribution information at a timing within the OFF duty of the main power switch unit to extract the surplus power unnecessary for the main supply destination between the power generation system and the power conditioner as the power distribution power. A power distribution circuit characterized by the above.

4. The power distribution circuit according to claim 2, comprising a current matching unit that matches the current of the power distribution line with the main line following the increase and decrease changes of the current of the main line caused by the maximum power point control. A power distribution circuit characterized by the above.

5. The power distribution circuit according to claim 1, comprising a power distribution control unit that controls the power distribution power switch unit, wherein the power distribution control unit acquires information regarding the amount of power that is necessary or unnecessary for the main supply destination among the power generation amounts of the power generation system (hereinafter referred to as "power distribution information"), and restricts the duty ratio of the pulse control of the power distribution power switch unit to "below the upper limit setting where no power loss occurs" according to the power distribution information, and extracts the surplus power unnecessary for the main supply destination between the power generation system and the power conditioner as the power distribution power. A power distribution circuit characterized by the above.

6. The power distribution circuit according to claim 1, wherein the power distribution power receiving unit includes a pulse power supply unit that sends the intermittent pulse-shaped power distribution power in the power distribution power switch unit to the power distribution power supply destination when the power distribution power supply destination enables pulse power supply. A power distribution circuit characterized by the above.

7. The power distribution circuit according to any one of claims 1 to 6, the power generation system that generates power, and a power conditioner that takes in power from the power generation system by the maximum power point control mediated by the power distribution circuit and outputs it to the main supply destination, wherein at least one of the power distribution circuit and the power conditioner includes a main current smoothing unit that smooths the pulsating current superimposed on the main line due to the power distribution while passing through the increase and decrease changes of the received current generated in the main line due to the maximum power point control. A surplus power utilization system characterized by the above.

8. The surplus power utilization system according to claim 7, wherein at least a time-difference power supply unit is provided as the power distribution destination of the power distribution circuit, the time-difference power supply unit stores the distributed power transmitted by the power distribution circuit as the surplus power that the main power supply destination does not need at that time, and transmits the stored surplus power to the main power supply destination with a time shift. The surplus power utilization system is characterized by the above.

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