JP6988618B2 - Power generation system and control method of power generation system - Google Patents

Description

The present invention relates to a power generation system.

For example, a power generation system equipped with a generator that generates AC power from renewable energy and an inverter that converts the AC power generated by the generator into DC power and supplies it to a power supply device or a power system is known. (For example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-163659

By the way, renewable energy is unstable energy that depends on natural conditions such as weather. Therefore, when the renewable energy fluctuates, the loss in the generator and the loss in the inverter fluctuate, and as a result, the loss generated in the entire power generation system fluctuates. Therefore, the loss generated in the entire power generation system may increase and the power generation efficiency may decrease.

The present invention has been made in view of such circumstances, and an object of the present invention is to reduce the loss generated in a power generation system.

One aspect of the present invention is a power generation system including a generator and a power conversion device for converting the generated power generated by the generator into DC, and switching of switching elements constituting the power conversion device. It is characterized by including a control unit that performs switching control for the switching element so that the total loss including the loss generated by the generator and the loss generated by the power conversion device is minimized while changing the frequency. It is a power generation system.

One aspect of the present invention is the above-mentioned power generation system, in which the control unit performs switching control on the switching element so that the generated power converted by the power conversion device is maximized.

One aspect of the present invention is the power generation system described above, wherein the control unit feedback-controls the output of the generator so that the output of the generator follows a target value, and the control frequency of the switching frequency is set. It is smaller than the resonance frequency of the feedback control at the time of load fluctuation and larger than the frequency of the rotation speed fluctuation of the generator.

One aspect of the present invention is the power generation system described above, further comprising a first temperature sensor for measuring the temperature of the switching element, and the control unit has a temperature measured by the first temperature sensor. When the temperature exceeds the threshold value of 1, the switching frequency is forcibly reduced.

One aspect of the present invention is the power generation system described above, further comprising a second temperature sensor for measuring the temperature of the generator, and the control unit has a temperature measured by the second temperature sensor. When the temperature exceeds the threshold value of 2, the switching frequency is forcibly increased.

As described above, according to the present invention, it is possible to reduce the loss generated in the power generation system.

It is a figure which shows an example of the schematic structure of the power generation system A provided with the power generation power converter which concerns on one Embodiment of this invention. It illustrates an embodiment in accordance with the generator losses P _G, inverter loss P _IV, and an example of a trend for the switching frequency fs of the total losses P _S of the present invention. It is a figure explaining the _{response angular frequency ω SW} which concerns on one Embodiment of this invention. It is a flow diagram of the minimum loss point follow-up control which concerns on one Embodiment of this invention. It is a flow diagram which shows the modification of the minimum loss point follow-up control which concerns on one Embodiment of this invention.

Hereinafter, the power generation power converter according to the embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an example of a schematic configuration of a power generation system A including a power generation power converter according to an embodiment of the present invention. As shown in FIG. 1, the power generation system A includes a power supply device 1, a generator 2, and a power generation power converter 3.

The power supply device 1 is a DC power supply, and for example, a secondary battery such as a nickel hydrogen battery or a lithium ion battery can be used. Further, the power supply device 1 may use an electric double layer capacitor (capacitor) instead of the secondary battery. Further, the power supply device 1 may be a device that rectifies the output from the AC power supply to direct current.

The generator 2 is a generator that generates electric power (hereinafter referred to as "generated electric power") by being driven by renewable energy, a steam turbine, or the like. In this embodiment, the generator 2 is a three-phase (U, V, W) alternator. Specifically, the generator 2 includes a rotor having a permanent magnet and a stator in which coils Lu, Lv, and Lw corresponding to each of the three phases (U, V, W) are wound in order in the rotation direction of the rotor. It is equipped with. Each of the coils Lu, Lv, and Lw of each phase is connected to the power generation power converter 3.

The power generation power converter 3 converts the generated power of the alternating current generated by the generator 2 into direct current and supplies it to the power supply device 1. Hereinafter, the configuration of the power generation power converter 3 according to the embodiment of the present invention will be specifically described.

The power generation converter 3 includes an inverter 4 and an inverter control unit 5. The inverter 4 is an example of the "power conversion device" of the present invention.

The inverter 4 converts the generated power of the alternating current generated by the generator 2 into direct current. Then, the inverter 4 supplies the generated power converted to direct current to the power supply device 1.

Specifically, the inverter 4 includes an output terminal N1, a reference terminal N2, and input terminals N3 to N5.

The output terminal N1 is connected to the positive electrode terminal of the power supply device 1 via the connection line L1. The reference terminal N2 is connected to the negative electrode terminal of the power supply device 1 via the connection line L2. Further, a coil Lu is connected to the input terminal N3. A coil Lv is connected to the input terminal N4. A coil Lw is connected to the input terminal N5.
Therefore, the inverter 4 converts the alternating current generated power input to the input terminals N3 to N5 into direct current and outputs it from the output terminal N1 to the power supply device 1.

The configuration of the inverter 4 will be specifically described below.

The inverter 4 has a plurality of switching elements SW, and the ON state and the OFF state of the switching elements are switched and controlled by the inverter control unit 5, so that the AC generated power from the generator 2 is converted into direct current. Output to power supply 1. As a result, the power generation device 1 is charged with the generated power. In this embodiment, a case where the six switching elements SW1 to SW6 are FETs (Field Effective Transistors) will be described, but the present invention is not limited to this, and for example, an IGBT (Insulated gate bipolar transistor) and a BJT (bipolar junction) are described. It may be a transistor). Further, the inverter 4 is not particularly limited in the number of switching elements SW.

Specifically, the switching elements SW1 and SW2 connected in series, the switching elements SW3 and SW4 connected in series, and the switching elements SW5 and SW6 connected in series are the output terminal N1 and the reference terminal N2. It is connected in parallel with.

The drain terminal of the switching element SW1 is connected to the output terminal N1. The source terminal of the switching element SW2 is connected to the reference terminal N2. The connection point (input terminal N3) between the source terminal of the switching element SW1 and the drain terminal of the switching element SW2 is connected to one end of the coil Lu.

The drain terminal of the switching element SW3 is connected to the drain terminal of the switching element SW1. The source terminal of the switching element SW4 is connected to the reference terminal N2. The connection point (input terminal N4) between the source terminal of the switching element SW3 and the drain terminal of the switching element SW4 is connected to one end of the coil Lv.

The drain terminal of the switching element SW5 is connected to the drain terminal of the switching element SW1. The source terminal of the switching element SW6 is connected to the reference terminal N2. The connection point (input terminal N5) between the source terminal of the switching element SW5 and the drain terminal of the switching element SW6 is connected to one end of the coil Lw.

Further, the gate terminals of the switching elements SW1 to SW6 are connected to the inverter control unit 5.

The inverter control unit 5 controls the drive of the inverter 4. Specifically, the inverter control unit 5 switches and controls the switching elements SW1 to SW6. The configuration of the inverter control unit 5 will be specifically described below.

The inverter control unit 5 includes a current detection unit 6, a voltage detection unit 7, and a control unit 8.

The current detection unit 6 detects the output current Iout output from the output terminal N1 of the inverter 4 to the power supply device 1. For example, the current detection unit 6 is provided on the connection line L1 and detects the output current Iout by detecting the current flowing through the connection sensor L1. Then, the current detection unit 6 outputs the detected output current Iout to the control unit 8.

The current detection unit 6 is not particularly limited as long as it is configured to detect the output current Iout, but is, for example, a current transformer (CT) including a transformer or a current sensor including a Hall element. Further, the current detection unit 6 may detect the output current Iout from the voltage across the shunt resistor connected in series with the connection line L1.

The voltage detection unit 7 detects the output voltage Vout output from the inverter 4 to the power supply device 1. For example, the voltage detection unit 7 detects the output voltage Vout by detecting the potential difference between the output terminal N1 and the reference terminal N2. The voltage detection unit 7 does not read the output voltage Vout output from the inverter 4 as it is, but for example, the voltage obtained by dividing the output voltage Vout by a resistance voltage divider circuit (hereinafter referred to as "voltage divider voltage"). ) May be read. In this case, the voltage detection unit 7 calculates the output voltage Vout from the read voltage dividing voltage based on the voltage dividing ratio of the resistance voltage dividing circuit.

The voltage detection unit 7 outputs the detected output voltage Vout to the control unit 8. As described above, since the output terminal N1 is connected to the positive electrode terminal of the power supply device 1 and the reference terminal N2 is connected to the negative electrode terminal of the power supply device 1, the output voltage Vout corresponds to the output voltage of the power supply device 1.

The control unit 8 switches and controls the switching elements SW1 to SW6 at an arbitrary switching frequency fsw. For example, the control unit 8 performs switching control for controlling the switching elements SW1 to SW6 in an on state or an off state by outputting a control signal to the gate terminal of the switching elements SW1 to SW6. This control signal is, for example, a PWM (Pulse Width Modulation) signal.

Specifically, the control unit 8 feedback-controls the output of the generator 2 by setting the detail ratio of the PWM signal so that the output of the generator 2 follows the target value. Here, the output of the generator 2 may be a current output from the generator 2 (generated current) or a voltage output from the generator 2 (generated voltage).

Further, the control unit 8 sets the switching frequency fsw of the inverter 4 with a second control system different from the feedback control control system (hereinafter, referred to as “first control system”). The switching frequency fsw corresponds to the frequency of the control signal.
Here, one feature of the present embodiment, while changing without fixing the switching frequency fsw of the inverter 4, loss generated by the generator 2 (hereinafter, referred to as "generator loss".) And P _G loss generated in the inverter 4 (hereinafter, "inverter loss" _{hereinafter.)} in a loss which is the sum of the _{P IV} (hereinafter, referred to as "total loss".) _{P S} is the minimum switching frequency fsw (hereinafter, _{"fsw min"} It is to perform the minimum loss point tracking control that constantly searches for.).

In other words, a minimum loss point tracking control, in a state where the generator 2 is driven, so that the total loss P _S is minimized, changing the switching frequency fsw (e.g., frequency control signal) as a parameter total loss P _S is to switching control of the inverter 4 so as to minimize while.

Hereinafter, the total loss P _S, is described with reference to FIG. Figure 2 is a diagram illustrating an embodiment in accordance with the generator losses P _G, inverter loss P _IV, and an example of a trend for the switching frequency fs of the total losses P _S of the present invention.

The present inventors have discovered that there as the switching frequency fsw increases, are both prone to inverter loss P _IV increases tend to generator losses P _G is reduced. This is because, as shown in FIG. 2, the loss on the vertical axis, the horizontal axis in graph switching frequency fsw, when plotting the generator losses P _G and the inverter loss P _IV is within a predetermined range of the switching frequency fsw in the point where the loss P _S is minimized (hereinafter, referred to as "minimum loss point".) exists. That is, the total losses P _S is within a predetermined range of the switching frequency fsw, so that always there is a minimum loss point. Therefore, the control unit 8 always searches for _{the switching frequency fsw min} of the minimum loss point while changing the switching frequency fsw even when the rotation speed of the generator 2 fluctuates due to the fluctuation of the renewable energy or the drive of the steam turbine. by to switching control, it is possible to reduce the total loss P _S.

Here, when the rotation speed of the generator 2 is constant, the tendency of the generated power Pout output from the tendency of the inverter 4 of the total losses P _S to the switching frequency fsw, a tendency opposite to each other. That is, when the rotation speed of the generator 2 is constant, the switching frequency f _SW of total losses P _S is minimized, and the switching frequency f _SW of generated power Pout becomes maximum, the same frequency. Therefore, in the minimum loss point tracking control, the control unit 8 according to the present embodiment _{changes the switching frequency f SW} of the inverter 4 when the generator 2 is driven, and the switching elements SW1 to maximize the generated power Pout. SW6 switching control is performed.

Since the minimum loss point also changes when the rotation speed of the generator 2 fluctuates, the response angle of the control system (second control system) that changes the switching frequency fsw in the minimum loss point tracking control as shown in FIG. The frequency ω _SW is set to a value larger than _{the frequency ω L} of the assumed rotation speed fluctuation of the generator 2. The response angular frequency ω _SW of the second control system is a frequency for controlling the switching frequency fsw (control frequency of the switching frequency fsw). It is desirable that the frequency ω _L of the assumed rotation speed fluctuation of the generator 2 is the maximum frequency of the assumed rotation speed fluctuation of the generator 2.
Further, when the response angular frequency ω _{SW is larger than the resonance angular frequency ωr (> ω L} ) of the first control system when the rotation speed of the generator 2 fluctuates, the switching frequency fsw is in a transient state (unstable state) such as resonance. ) May be followed.

Therefore, the response angle frequency ω _SW is set to a value smaller than the resonance angle frequency ωr. For example, the response angular frequency ω _SW is set so as to satisfy the following condition (1).
ω _L << ω _SW << ωr ... (1)

Next, the flow of the operation of the minimum loss point tracking control according to the embodiment of the present invention will be described with reference to FIG. FIG. 4 is a flow chart of minimum loss point tracking control according to an embodiment of the present invention.

First, the control unit 8 drives the inverter 4 by outputting a control signal whose switching frequency fsw is set to a preset initial value fsw0 to the switching elements SW1 to SW6. As a result, the inverter 4 whose switching is controlled at the switching frequency fsw = initial value fsw0 converts the AC generated power generated by the generator 2 into DC and supplies the DC generated power Pout to the power supply device 1. (Step S101). The initial value fsw0 is, for example, a reference value obtained from a simulation, a design value, or a reference value obtained on a trial basis.

Next, the control unit 8 adds a minute frequency Δfsw × increase / decrease flag F to the current switching frequency fsw while the generator 2 is being driven. Here, the minute frequency Δfsw is preset and is a change amount that changes the switching frequency fsw in the minimum loss point tracking control. The increase / decrease flag F determines whether to increase or decrease the switching frequency fsw when the switching frequency fsw is changed in the minimum loss point tracking control. For example, if the increase / decrease flag F is "+1", the switching frequency fsw is increased, and if the increase / decrease flag F is "-1", the switching frequency fsw is decreased. The initial value of the increase / decrease flag F is set in step S101, and is set to "+1" as the initial value in the present embodiment. However, the initial value of the increase / decrease flag F may be "-1".

The current detection unit 6 detects the output current Iout output from the inverter 4 to the power supply device 1, and outputs the detected output current Iout to the control unit 8. Further, the voltage detection unit 7 detects the output voltage Vout output from the inverter 4 to the power supply device 1, and outputs the detected output voltage Vout to the control unit 8 (step S103).

The control unit 8 calculates the current power generation power Pout (= Iout × Vout) by multiplying the output current Iout acquired from the current detection unit 6 and the output voltage Vout acquired from the voltage detection unit 7 (step). S104).

When the control unit 8 calculates the current power generation power Pout, the control unit 8 compares the calculated current power generation power Pout with the previously calculated power generation power Pout (step S104). In order to prevent the explanation from becoming complicated, the power generation power Pout calculated last time is referred to as the power generation power Ref. The initial value of the generated power Pref is set in step S101, and is set to "0" in this embodiment.

The control unit 8 compares the current power generation power Pout with the previous power generation power Pref, and when the current power generation power Pout is larger than the previous power generation power Pref (Pout> Pref), the sign of the increase / decrease flag F is Not going to change. Then, the control unit 8 sets the current generated power Pout as the previous generated power Pref (step S107), and returns to the process of step S102.

On the other hand, the control unit 8 compares the current power generation power Pout with the previous power generation power Pref, and when the current power generation power Pout is equal to or less than the previous power generation power Pref (Pout ≦ Pref), the increase / decrease flag F Invert the sign of (step S106). Then, the control unit 8 sets the current generated power Pout as the previous generated power Pref (step S107), and returns to the process of step S102.

In this way, by repeating steps S102 to S107, the control unit 8 increases or decreases the generated power Pout by a minute frequency Δfsw from the previous switching frequency fsw with the switching frequency fsw as a parameter, and the generated power Pout is higher than the previous value. The inverter 4 is switched and controlled so as to be large. This enables the control unit 8 to search for the minimum loss point while increasing or decreasing the switching frequency fsw. As a result, the power generation system A does not depend on the rotation speed of the generator 2, the temperature of the generator 2 and the switching elements SW1 to SW6, the power generation voltage of the generator 2, the individual variation of the generator 2 and the switching elements SW1 to SW6, and the like. , The operation of the generator 2 can be continued with the minimum loss.
Further, the power generation system A can maintain the minimum loss and always maintain high power generation efficiency even if the rotation speed of the generator 2 fluctuates.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs and the like within a range that does not deviate from the gist of the present invention.

(Modification 1)
In the above embodiment, the range of the switching frequency fsw to be changed may be limited in the minimum loss point tracking control. For example, the control unit 8 sets the switching frequency fsw in the minimum loss point tracking control in _{the range between the minimum value fsw MIN} (minimum value) and the maximum value fsw _MAX (maximum value) (fsw _MIN ≤ fsw ≤ fsw _MAX). ) May be changed.

(Modification 2)
In the above embodiment, the control unit 8 adds the minute frequency Δfsw × increase / decrease flag F to the switching frequency fsw (initial value fsw0) after setting the initial conditions in the process of step S101 at the start of the minimum loss point tracking control. After that (step S102), acquisition of the output current Iout and the output voltage Vout (step S103), and calculation of the generated power Pout (step S104) were performed, but the present invention is not limited thereto. For example, at the start of the minimum loss point tracking control, the control unit 8 may execute the processing of steps S103 and S104 without performing the processing of step S102 after performing the processing of step S101. In this case, the control unit 8 performs the process of step S102 after the process of step S107.

Specifically, as shown in FIG. 5, the control unit 8 first sets the initial conditions. That is, the control unit 8 drives the inverter 4 by outputting the control signal whose switching frequency fsw is set to the preset initial value fsw0 to the switching elements SW1 to SW6, as in the processing of the switch 101. Further, the control unit 8 sets the previous generated power Pref to the initial value “0” and the increase / decrease flag F to the initial value “+1” (step S201).

After the initial conditions are set, the current detection unit 6 detects the output current Iout output from the inverter 4 to the power supply device 1, and outputs the detected output current Iout to the control unit 8. Further, the voltage detection unit 7 detects the output voltage Vout output from the inverter 4 to the power supply device 1, and outputs the detected output voltage Vout to the control unit 8 (step S202).

The control unit 8 calculates the generated power Pout (= Iout × Vout) by multiplying the output current Iout acquired from the current detection unit 6 and the output voltage Vout acquired from the voltage detection unit 7 (step S203). ..

When the control unit 8 calculates the current power generation power Pout, the calculated current power generation power Pout is compared with the previously calculated power generation power Pref (step S204), and the current power generation power Pout is the previous power generation power. If it is larger than Pref (Pout> Pref), the sign of the increase / decrease flag F is not changed. Then, the control unit 8 sets the current generated power Pout as the previous generated power Def (step S206). On the other hand, the control unit 8 compares the current power generation power Pout with the previous power generation power Pref, and when the current power generation power Pout is equal to or less than the previous power generation power Pref (Pout ≦ Pref), the increase / decrease flag F Invert the sign of (step S205). Then, the control unit 8 sets the current generated power Pout as the previous generated power Def (step S206). After that, the control unit 8 adds a minute frequency Δfsw × increase / decrease flag F to the current switching frequency fsw (step S207), and returns to the process of step S202.

(Modification 3)
In the above embodiment, the power generation system A may include a first temperature sensor that measures the temperature Tsw of the switching elements SW1 to SW6. Then, in the minimum loss point tracking control, when the temperature Tsw measured by the first temperature sensor becomes equal to or higher than the preset first threshold value Tth1, the control unit 8 sets the temperature Tsw to the first. The switching frequency fsw may be forcibly reduced until it becomes less than the threshold value Tth1 of. For example, the control unit 8 may forcibly reduce the switching frequency fsw as an interrupt process when the temperature Tsw becomes equal to or higher than the first threshold value Tth1 even if the minimum loss point tracking control is performed. As a result, the loss (inverter loss) due to the switching elements SW1 to SW6 is reduced, and the control unit 8 can prevent the switching elements SW1 to SW6 from failing due to heat generation. As a method for forcibly reducing the switching frequency fsw, for example, there is a method for forcibly inverting the sign of the increase / decrease flag F.

(Modification example 4)
In the above embodiment, the power generation system A may include a second temperature sensor that measures _{the temperature TG of the generator 2. The temperature TG} of the generator 2 is, for example, the temperature of each of the coils Lu, Lv, and Lw. Then, in the minimum loss point tracking control, when the temperature _TG measured by the second temperature sensor becomes equal to or higher than the preset second threshold value Tth2 _{, the control unit 8 sets the temperature TG.} The switching frequency fsw may be forcibly increased until it becomes less than the second threshold value Tth2. _{For example, the control unit 8 may forcibly increase the switching frequency fsw as interrupt processing when the temperature TG} becomes equal to or higher than the second threshold value Tth2 even if the minimum loss point tracking control is performed. .. As a result, the generator loss is reduced, and the control unit 8 can prevent the generator 2 from failing due to the heat generated by the coils Lu, Lv, and Lw. As a method for forcibly increasing the switching frequency fsw, for example, there is a method for forcibly inverting the sign of the increase / decrease flag F.

(Modification 5)
In the above embodiment, the power generation system A may include both the first temperature sensor and the second temperature sensor. Then, when the temperature Tsw becomes the first threshold value Tth1 or more and the temperature _TG becomes the second threshold value Tth2 or more, the control unit 8 reduces the output (for example, the power generation current) of the generator 2. Control to do. For example, the control unit 8 lowers the target value of the output of the generator 2. As a result, both the inverter loss and the generator loss are reduced, and it is possible to prevent a failure due to heat generation between the switching elements SW1 to SW6 and the generator 2.

(Modification 6)
In the above embodiment, the control unit 8 acquires the generated power Pout by multiplying the output current Iout detected by the current detection unit 6 and the output voltage Vout detected by the voltage detection unit 7. Not limited to this. That is, the control unit 8 only needs to be able to acquire the generated power Pout, and the acquisition method is not particularly limited. For example, the control unit 8 may acquire the generated power Pout by the power sensor provided on the connection line L1. Further, the control unit 8 may acquire the generated power Pout by calculating the generated power Pout from the generated current of the generator 2, the conversion efficiency of the inverter 4, and the like.

(Modification 7)
In the above embodiment, the case where the generated power Pout output from the inverter 4 is supplied to the power supply device 1 has been described, but the present invention is not limited to this. That is, the generated power Pout output from the inverter 4 may be supplied to the load, and the type of the load is not particularly limited. For example, the power generation system A may further include a conversion device that converts the generated power Pout output from the inverter 4 into alternating current, and supply the generated power converted to alternating current by the conversion device to a load such as a power system. ..

As described above, the present inventors, as the switching frequency fsw increases, the generator losses P _G are both inverter loss P _IV in tends to decrease discovered that tends to increase, the total losses P _S Found that there is a minimum loss point with the switching frequency fsw as a parameter. Generated power converter 3 according to the present embodiment, which has been made based on these findings, while changing the switching frequency of the switching element SW1~SW6 constituting the inverter 4, a generator loss P _G a control unit 8 that the total losses _{P S} including the inverter loss _{P IV} is switching control of the switching element SW1~SW6 to minimize.

According to such a configuration, even when the engine speed fluctuation of the generator 2 is generated, it is possible to maintain the total losses P _S to always minimized losses. Therefore, it is possible to reduce the loss generated in the power generation system A due to the fluctuation of the rotation speed of the generator 2.

More specifically, the control unit 8 switches and controls the switching elements SW1 to SW6 so that the generated power Pout converted to direct current by the inverter 4 is maximized.

Further, the control unit 8 may be provided with a configuration in which the output of the generator 2 is feedback-controlled. The control frequency of the switching frequency fsw may be set to a value smaller than the resonance frequency of the feedback control at the time of load fluctuation and larger than the frequency of the rotation speed fluctuation of the generator 2.

According to such a configuration, the switching frequency fsw set in the minimum loss point tracking control can sufficiently respond and follow the fluctuation of the rotation speed of the generator 2 without following the transient state such as resonance. ..

Further, the power generation system A may further include a first temperature sensor for measuring the temperature Tsw of the switching elements SW1 to SW6. Then, the control unit 8 may forcibly reduce the switching frequency fsw when the temperature Tsw measured by the first temperature sensor becomes equal to or higher than the first threshold value Tth1.

According to such a configuration, the inverter loss is reduced, and it is possible to prevent the switching elements SW1 to SW6 from failing due to heat generation.

Further, the power generation system A may further include a second temperature sensor for measuring the temperature of the generator 2. Then, the control unit 8 may _{forcibly increase the switching frequency fsw when the temperature TG} measured by the second temperature sensor becomes equal to or higher than the second threshold value Tth2.

According to such a configuration, the generator loss is reduced, and it is possible to prevent the generator 2 from failing due to the heat generated by the coils Lu, Lv, and Lw.

A Power generation system 1 Power supply device 2 Generator 3 Power generation power converter 4 Inverter 5 Inverter control unit 6 Current detection unit 7 Voltage detection unit 8 Control unit

Claims (7)

A power generation system including a generator and a power conversion device that converts the generated power generated by the generator into DC.
While changing the switching frequency of the switching element constituting the power conversion device, the total loss including the loss generated by the generator and the loss generated by the power conversion device is minimized with respect to the switching element. A power generation system characterized by having a control unit that performs follow-up control so that the switching frequency fluctuates continuously. The power generation system according to claim 1, wherein the control unit performs switching control on the switching element so that the generated power converted by the power conversion device is maximized. The control unit feedback-controls the output of the generator so that the output of the generator follows the target value.
The power generation according to claim 1 or 2, wherein the control frequency of the switching frequency is smaller than the resonance frequency of the feedback control at the time of load fluctuation and larger than the frequency of the rotation speed fluctuation of the generator. system. A first temperature sensor for measuring the temperature of the switching element is further provided.
One of claims 1 to 3, wherein the control unit forcibly reduces the switching frequency when the temperature measured by the first temperature sensor becomes equal to or higher than the first threshold value. The power generation system described in paragraph 1. Further equipped with a second temperature sensor for measuring the temperature of the generator,
Any of claims 1 to 3, wherein the control unit forcibly increases the switching frequency when the temperature measured by the second temperature sensor becomes equal to or higher than the second threshold value. The power generation system described in paragraph 1. A method for controlling a power generation system including a generator and a power conversion device including a switching element for converting the generated power generated by the generator.
The step to get the reference value and
A step of acquiring a comparison value corresponding to a total loss, which is the sum of the loss generated by the generator and the loss generated by the power converter.
A step of comparing the reference value with the comparison value,
A step of increasing or decreasing the switching frequency of the switching element according to the comparison result between the reference value and the comparison value, and
With the step of updating the reference value to the comparison value
How to control the power generation system, including. The control method for a power generation system according to claim 6, wherein the comparison value is the generated power converted by the power conversion device.

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