JP2008206265A - Cogeneration equipment - Google Patents

Abstract

A cogeneration apparatus is provided that prevents a reverse power flow in which output power flows into a commercial power system when a commercial power system fails, and supplies as much power as possible to an electric load.
A generator connected to a first power supply path for AC power from a commercial power system to an electric load, a battery for storing DC power, and a first power supply path. And when the power failure of the commercial power system 12 is detected, the first switch 24 is turned off to cut off the power supply from the generator 32 to the commercial power system 12, while generating power. After the power supply from the machine 32 to the commercial power system 12 is cut off, the battery 36 is connected to the inverter circuit 34c of the generator 32 (more precisely, the booster circuit 34b arranged on the input side of the inverter circuit 34c), The output of the generator 32 and the output of the battery 36 are converted into AC power and supplied to the electric load 14.
[Selection] Figure 1

Description

  The present invention relates to a cogeneration apparatus, and more particularly to a cogeneration apparatus that supplies as much power as possible to a load when a commercial power system fails.

In recent years, a generator driven by an internal combustion engine is connected to an AC power supply path from a commercial power system to an electric load to supply power to the electric load in conjunction with the commercial power system, and exhaust heat from the internal combustion engine. A so-called cogeneration apparatus has been proposed in which hot water or the like generated by using a heat source is supplied to a heat load. For example, a technique described in Patent Document 1 can be given.
JP-A-5-328615

  In the technology described in Patent Document 1, the private engine power generation facility is connected to the private generator load, and the other three loads are connected to the commercial power supply facility (commercial power system) and the private engine power generation facility in a switchable manner. The When the operation load amount of the self-origin side load is equal to or greater than the predetermined value, the other three loads are connected to the commercial power supply equipment, while the other three loads are sequentially increased as the operation load amount decreases from the predetermined value. It is configured to be connected to a private engine power generation facility.

  By the way, in this type of cogeneration apparatus, when a commercial power system fails, the cogeneration apparatus is usually stopped to prevent a reverse power flow in which power output from the cogeneration apparatus flows into the commercial power system. On the other hand, it is conceivable to operate the cogeneration device without supplying it to the electric load without stopping it even in the event of a power failure, but in that case, the upper limit of the amount of power that can be supplied is of course the original maximum output of the cogeneration device Limited to

  Therefore, the object of the present invention is to solve the above-mentioned problems, and when the commercial power system fails, the power output from the cogeneration device prevents reverse power flow flowing into the commercial power system, and as much as possible to the electric load. An object of the present invention is to provide a cogeneration apparatus that supplies electric power.

  In order to solve the above-described problem, in claim 1, a generator connected to an AC power supply path from a commercial power system to an electric load and an internal combustion engine that drives the generator are provided. In the cogeneration system for supplying exhaust heat from the internal combustion engine to a heat load, when a battery storing DC power, a switch arranged in the power supply path, or a power failure in the commercial power system is detected, the switch is turned off. Power supply shut-off means for shutting off power supply from the generator to the commercial power system, and after power supply from the generator to the commercial power system is shut off, the battery is used as an inverter circuit of the generator. A battery connecting means is provided for connecting, and converting the output of the generator and the output of the battery into AC power to be supplied to the electric load.

  According to a second aspect of the present invention, the battery detection unit includes a voltage detection unit that detects an output voltage of the inverter circuit, and the battery connection unit connects the battery to the inverter circuit when the detected voltage is less than a predetermined value. Configured to do.

  According to a third aspect of the present invention, the battery connecting means is configured to connect the battery to a starting device of the internal combustion engine when starting the generator.

  According to a fourth aspect of the present invention, the starter for the internal combustion engine is configured to be one of the generator and the starter motor.

  The cogeneration apparatus according to claim 1 includes a generator connected to a power supply path of AC power from the commercial power system to the electrical load, and a switch disposed in the power supply path. When a power outage is detected, the switch is turned off to cut off the power supply from the generator to the commercial power grid. The reverse power flow flowing into the system can be reliably prevented.

  It also has a battery that stores DC power, and after the power supply from the generator to the commercial power system is cut off, the battery is connected to the inverter circuit of the generator, and the generator output and the battery output are connected to the AC power. Therefore, the electric power to be supplied to the electric load can be increased by the amount of electric power output from the battery. Thereby, even when the electrical load exceeds the original maximum output of the cogeneration apparatus, if the excess is within the range of the output of the battery, the necessary power can be supplied to the electrical load.

  Further, even when an instantaneous overload occurs due to an inrush current when the load does not exceed the original maximum output of the cogeneration apparatus, power can be stably supplied to the electric load.

  In the cogeneration apparatus according to claim 2, the output voltage of the inverter circuit is detected, and when the detected voltage is less than a predetermined value, the battery is connected to the inverter circuit. In addition, the battery outputs to the inverter circuit only when the output voltage of the inverter circuit decreases due to an increase in the operation load amount of the electric load, and the power consumption of the battery can be reduced.

  In the cogeneration apparatus according to claim 3, since the battery is connected to the starter of the internal combustion engine when starting the generator, the internal combustion engine is reliably started by the battery in addition to the effects described above. can do.

  In the cogeneration apparatus according to claim 4, the starter of the internal combustion engine is configured to be one of a generator (specifically, a starter generator) and a starter motor. In addition, the internal combustion engine can be started more reliably by the battery.

  The best mode for carrying out a cogeneration apparatus according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a block diagram generally showing a cogeneration apparatus according to a first embodiment of the present invention.

  As shown in the figure, a cogeneration apparatus (denoted by reference numeral 10) has a connection point 18 connected to an AC power supply path (power line; first power supply path) 16 from a commercial power system (system power supply) 12 to an electric load 14. A power generation device 20 connected via the power supply is provided. The commercial power system 12 outputs AC power of 50 Hz (or 60 Hz) at AC 100/200 V from a single-phase three-wire.

  As will be described later, the power generation device 20 has a relatively small output, and is intended for use in private houses. The electric load 14 includes a plurality of, specifically four, AC electric devices 14a, 14b, 14c, and 14d. For example, 14a is a lighting fixture, 14b is a washing machine, 14c is a refrigerator, and 14d is an air conditioner.

  A main breaker box 22, a first switch (switch) 24, and a switchboard 26 are arranged in order from the commercial power system 12 side (upstream side) in the first power supply path 16, and an electric load is arranged downstream of the main breaker box 22. 14 is connected. Inside the main breaker box 22, there is provided a main breaker 22a that prevents energization of overcurrent.

  As shown in the figure, the first switch 24 is arranged at a position upstream of the connection point 18 of the power generator 20 (on the side of the commercial power system 12) in the first power supply path 16, and when turned on, the commercial power While the system 12 is connected to the electric load 14 and the power generation device 20, when it is turned off, the connection with the electric load 14 and the like is interrupted, and power supply (reverse power flow) from the power generation device 20 to the commercial power system 12 is prevented. Is done. Note that the first switch 24 is turned on during normal times (when the commercial power system 12 is not out of power).

  The first power supply path 16 is branched into four branch paths 16a, 16b, 16c, and 16d in the switchboard 26, and the electrical loads 14a, 14b, 14c, and 14d are connected via the corresponding breakers 26a, 26b, 26c, and 26d. Connected to. The breakers 26a to 26d are turned off when an overcurrent flows like the main breaker 22a described above, and prevent the overcurrent from flowing to the connected electrical load 14. As shown in FIG. 1, the main breaker box 22, the first switch 24, the switchboard 26, and the like are connected via terminals, but the description of the terminals is omitted.

  The power generation device 20 includes an internal combustion engine (hereinafter referred to as “engine”) 30, a generator 32 driven by the engine 30, and an inverter 34 connected to the generator 32.

  Hereinafter, each element constituting the power generation apparatus 20 will be described. The engine 30 is a water-cooled four-cycle single-cylinder OHV type spark ignition engine that uses gasoline as fuel, and has a displacement of, for example, 163 cc. A cooling water passage (not shown) of the engine 30 is connected to the pipe 36, and the pipe 36 is guided into the muffler 40 of the engine 30 and then guided into the hot water storage tank (thermal load) 42. The cooling water for the engine 30 is circulated inside the pipe 36.

  When the cooling water heated by driving the engine 30 passes through the inside of the muffler 40, the cooling water is further heated by the exhaust gas and sent to the hot water storage tank 42, and the temperature of the stored water stored therein is increased by heat exchange to increase the temperature of the hot water. Is generated. The cooling water cooled by the heat exchange is returned to the cooling water passage to cool the engine 30.

  In this way, hot water or the like is generated using the exhaust heat of the engine 30. The hot water stored in the hot water tank 42 is supplied to a heat load such as a hot water supply facility (not shown) for a kitchen or a bath, for example.

  The generator 32 is composed of a three-phase AC generator, and a rotor (not shown) is driven by an engine 30 that is controlled to rotate at a predetermined rotational speed, and outputs AC power. The maximum power generation output of the generator 32 is set to 1.0 kW, for example.

  The generator 32 also functions as a starter (starter) for the engine 30. Specifically, when a stator coil (not shown) of the generator 32 is energized, the rotor is rotated, thereby cranking and starting the engine 30 connected to the rotor. Thus, the generator 32 is a so-called starter generator having a function as a starting device of the engine 30 and a function as a generator (alternator) that outputs AC power.

  As shown in the figure, the inverter 34 boosts the direct current rectified by the three-phase bridge circuit 34a to a predetermined voltage value, and a three-phase bridge circuit (drive circuit) 34a that rectifies the alternating current output from the generator 32 into direct current. A booster circuit 34b and an inverter circuit 34c that converts the boosted direct current into alternating current, more specifically, alternating current composed of single-phase three-wire 100 / 200V at the same frequency as the commercial power system 12. The inverter circuit 34c includes a plurality of switching elements made of IGBT (Insulated-Gate Bipolar Transistor), and converts direct current into alternating current through their switching action.

  The inverter 34 further includes a choke coil 34d for removing noise of the inverter circuit output, a second switch 34e, a common coil 34f for removing noise of the second switch output, and a current for detecting a current value of the common coil output. A sensor (CT (Current Transformer)) 34g is provided.

  The second switch 34e supplies the inverter circuit output to the electric load 14 when turned on, and cuts off (cuts) the output when turned off. A second current sensor 34h is connected between the choke coil 34d and the second switch 34e, and generates an output indicating the current of the AC power flowing therethrough.

  The inverter 34 is connected to the first power supply path 16 through the second power supply path 44 and the connection point 18. Thereby, the alternating current power output from the inverter 34 is supplied to each electric load 14a-14d via the 2nd electric power feeding path 44, the connection point 18, the 1st electric power feeding path 16, and the switchboard 26 (breakers 26a-26d). Is done. A noise filter 46 is inserted between the inverter 34 and the second power supply path 44 to remove noise from the output of the inverter 34.

  The cogeneration apparatus 10 further includes an electronic control unit (ECU) 50 formed of a microcomputer and a current / voltage sensor 52 connected to the first power supply path 16. The current / voltage sensor 52 outputs a signal corresponding to the voltage, current, and phase (sine wave) of AC power flowing through the first power supply path 16 and sends the signal to the ECU 50.

  Based on the output of the current / voltage sensor 52, the ECU 50 supplies the AC power through the first power supply path 16 (normal) or does not supply the AC power (whether a power failure occurs). Is detected, and when AC power is supplied, the phase thereof is detected. The ECU 50 controls operations of the first switch 24, the engine 30, the inverter circuit 34c, the second switch 34e, and the like based on the detected value, which will be described later.

  In addition to the power generator 20, the cogeneration apparatus 10 includes a battery 60 that stores DC power, and a DC / DC converter unit 64 that is connected to the battery 60 via a power line 62 and boosts the output of the battery 60. .

  The battery 60 is formed by connecting an appropriate number of nickel-metal hydride (Ni-MH) batteries in series, and stores, for example, DC power of 12V. The DC / DC converter unit 64 includes first and second DC / DC converters 64a and 64b for stepping up and stepping down the voltage of electric power input by the switching action of an IGBT (not shown) until reaching a predetermined voltage value, and an anode A diode 64c having a terminal connected to the output side of the inverter 34 and a cathode terminal connected to the second DC / DC converter 64b side, and a third switch 64d are provided.

  The output of the battery 60 is boosted to a predetermined voltage by the first DC / DC converter 64a and sent to the third switch 64d. When the third switch 64d is turned on, the output of the battery 60 boosted by the first DC / DC converter 64a is supplied to a changeover switch (described later) 66, while when the third switch 64d is turned off, the output is cut off ( Cut).

  The changeover switch 66 is configured to be switchable between a first terminal 66a connected to the three-phase bridge circuit 34a and a second terminal 66b connected to the booster circuit 34b. Therefore, when the third switch 64d of the DC / DC converter unit 64 is turned on and the first terminal 66a of the changeover switch 66 is selected, the battery 60 is connected to the three-phase bridge circuit 34a of the inverter 34, When the second terminal 66b is selected, it is connected to the booster circuit 34b (in other words, the inverter circuit 34c of the inverter 34). When the third switch 64d is turned off, the connection between the battery 60 and the inverter 34 is cut off regardless of the operation (selection) of the changeover switch 66. During normal operation (when there is no power failure), the third switch 64d is turned off, and the changeover switch 66 selects the second terminal 66b.

  The AC power output from the inverter 34 is converted to DC by a diode 64c in a predetermined operation state and input to the second DC / DC converter 64b, where it is dropped to an appropriate voltage, and then the battery 60 To be charged.

  FIG. 2 is a flowchart showing the operation of the cogeneration apparatus 10, more specifically, the ECU 50.

  In the following description, it is first determined in S10 whether or not the commercial power system 12 has failed. This is determined based on the output of the current / voltage sensor 52 described above. Specifically, when the signal indicating the desired AC power is output from the current / voltage sensor 52, the commercial power system 12 is determined to be normal, while when the signal is not output, the commercial power system 12 has failed. Judge.

  When the result in S10 is negative and the commercial power system 12 is determined to be normal, the process proceeds to S12, the phase of the output (AC power) of the commercial power system 12 is detected by the current / voltage sensor 52, and the process proceeds to S14 to perform a predetermined operation. When the condition is satisfied, the AC power having the same phase as the detected output (AC power) of the commercial power system 12 is output, that is, the engine 30 is started so as to perform the synchronous operation. To drive.

  FIG. 3 is a time chart for explaining the synchronous operation of the power generation apparatus 20.

  As shown in the figure, when the commercial power system 12 is normal, the power generation device 20 is driven to output AC power having the same phase as the output phase of the commercial power system 12. Specifically, the ECU 50 inputs the detected output of the AC power of the commercial power system 12 to the inverter circuit 34c via the signal line. The inverter circuit 34c outputs AC power whose phase matches the input value.

  The engine 30 is started when the commercial power system 12 is normal by supplying the power of the commercial power system 12 to the generator 32 as an operating power source. That is, the electric power of the commercial power system 12 is supplied to a stator coil of the generator 32 through a power supply path (power line) (not shown) to rotate the rotor, thereby cranking and starting the engine 30.

  The AC power matched at least in phase with the AC power of the commercial power system 12 by the inverter circuit 34 c is supplied to the electric load 14 via the second power supply path 44, the connection point 18, and the first power supply path 16. . It is assumed that the second switch 34e is turned on during normal operation (when there is no power failure).

  As described above, when the commercial power system 12 is normal and a predetermined operation condition is satisfied, the synchronous operation is performed to output the AC power having the same phase as the detected AC power phase of the commercial power system 12. The power generator 20 is driven and connected to the commercial power system 12. Thereby, both the electric power of the commercial power system 12 and the electric power of the power generator 20 are supplied to the electric load 14. The electric load 14 operates with the output of the power generation device 20 when the output of the power generation device 20 is sufficient, and operates with the output of the commercial power system 12 when it is insufficient.

  Returning to the description of the flow chart of FIG. 2, when the result in S10 is affirmative and it is determined that the commercial power system 12 is out of power, the process proceeds to S16, and the first switch 24 is turned off. That is, the reverse power flow is prevented by turning off the first switch 24 to cut off the power supply from the power generator 20 to the commercial power system 12.

  Next, in S18, it is determined whether or not the power generation device 20 is stopped. This is determined based on, for example, the output of the second current sensor 34h described above. This determination is usually denied because the power generation device 20 is already driven in the process of S14, but it is also conceivable that the power generation device 20 is stopped for some reason. Therefore, when the result in S18 is affirmative, the power generation device 20 is driven (started) by proceeding to S20 and S22 so that the power generation device 20 is used as an emergency power source in the event of a power failure.

  Specifically, in S20, the third switch 64d of the DC / DC converter unit 64 is turned on, and the changeover switch 66 is driven to select the first terminal 66a. Thereby, the output of the DC / DC converter unit 64 (in other words, the output of the battery 60 boosted by the first DC / DC converter 64a) is supplied to the generator 32 via the changeover switch 66 and the three-phase bridge circuit 34a. The rotor is rotated by being supplied to the stator coil of the motor, whereby the engine 30 is cranked and started, and the power generator 20 is started (driven). As described above, the battery 60 is used as an operation power source for starting the engine 30 when the commercial power system 12 has a power failure.

  When the power generation device 20 is started, the process proceeds to S22 where the third switch 64d of the DC / DC converter unit 64 is turned off and the changeover switch 66 is driven so as to select the second terminal 66b. Thereby, the electric power supplied from the battery 60 to the generator 32 is interrupted. If the result in S18 is NO, the processes in S20 and S22 are skipped.

  Next, in S24, the third switch 64d of the DC / DC converter unit 64 is turned on. Since the second terminal 66b of the changeover switch 66 is selected, the output of the DC / DC converter unit 64 (that is, the output of the battery 60) is an inverter via the changeover switch 66 and the booster circuit 34b by the process of S24. It is supplied to the circuit 34c. Thus, the battery 60 is connected to the inverter circuit 34c of the generator 32 at the time of a power failure.

  Here, the DC power supplied to the booster circuit 34b, in other words, the output power of the DC / DC converter unit 64 will be described. The voltage value is the output voltage of the generator 32 (more precisely, a three-phase bridge circuit). 34a) is set to be lower than the output voltage 34a) by a predetermined value. For example, when the output voltage of the three-phase bridge circuit 34a is about DC 280V, the power of the DC / DC converter unit 64 is set to be a voltage of about DC 270V. This will be described with reference to FIG.

  FIG. 4 is a time chart showing output voltages of the generator 32 (more precisely, the three-phase bridge circuit 34a) and the DC / DC converter unit 64.

  When the operating load of the electric load 14 is less than the rated output (1.0 kW) of the generator 32 during a power failure, the generator 32 is operated so that the output voltage of the three-phase bridge circuit 34a is DC 280V (rated voltage). Be made. At this time, since there is a potential difference of about 10 V between the output voltage of the three-phase bridge circuit 34 a and the output voltage of the DC / DC converter unit 64, the output of the DC / DC converter unit 64 is not supplied to the inverter 34.

  Next, when the electric load 14 increases and exceeds 1.0 kW, the output voltage of the generator 32, that is, the output voltage of the three-phase bridge circuit 34a gradually decreases as shown in FIG. Thereafter, when the output voltage of the three-phase bridge circuit 34a drops to the set output voltage (DC 270 V) of the DC / DC converter unit 64 at the time point ta (when the same voltage as the output of the DC / DC converter unit 64), Since there is no potential difference between the output of the three-phase bridge circuit 34a and the output of the DC / DC converter unit 64, the output of the DC / DC converter unit 64 is supplied to the booster circuit 34b. Thereby, the booster circuit 34b of the inverter 34 is supplied with the power of the three-phase bridge circuit 34a and the DC / DC converter unit 64, in other words, both the power of the generator 32 and the battery 60.

  In this way, the DC power input to the booster circuit 34b is boosted and then converted into AC power by the inverter circuit 34c and supplied to the electric load 14. Therefore, the electric load 14 is supplied with both the power of the power generation device 20 and the power of the battery 60, that is, the amount of power increased by the power of the battery 60 to the power of the power generation device 20. Thus, the output of the power generator 20 is backed up by the output of the battery 60 when the output voltage of the three-phase bridge circuit 34a is equal to or lower than the output voltage of the DC / DC converter unit 64 (when in an overload state).

  When the overload state is eliminated by the backup by the battery output, the output voltage of the three-phase bridge circuit 34a that has been lowered gradually increases toward the rated voltage (DC 280 V). For this reason, when the output voltage of the three-phase bridge circuit 34a exceeds the output voltage (DC 270 V) of the DC / DC converter unit 64 at time tb and a potential difference occurs, the supply of the output of the DC / DC converter unit 64 to the inverter 34 is stopped. Is done.

  As described above, the output of the battery 60 is supplied to the inverter 34 only when the output voltage of the three-phase bridge circuit 34 a is equal to or lower than the output voltage of the DC / DC converter unit 64. When the remaining amount of the battery 60 decreases due to power supply to the inverter 34 or the like, the battery 60 is charged with the power output from the inverter 34.

  Returning to the description of FIG. 2, the process then proceeds to S26, in which it is determined whether the commercial power system 12 has been restored (whether the power failure has been completed). This determination is also made based on the output of the current / voltage sensor 52.

  When the result in S26 is negative, the above determination is repeated. When the result is positive, the process proceeds to S28, and the third switch 64d of the DC / DC converter unit 64 is turned off. Thereby, the power supply from the battery 60 to the inverter 34 is cut off, that is, the backup by the battery 60 is ended.

  Next, the process proceeds to S30, the second switch 34e is turned off, and the electric power supplied from the power generation apparatus 20 to the electric load 14 is temporarily interrupted. Then, the process proceeds to S32, where the first switch 24 is turned on to turn off the commercial power system 12. The output AC power is supplied to the electric load 14.

  Next, the process proceeds to S34, and the phase of the output (AC power) of the commercial power system 12 is detected. The process proceeds to S36, and when a predetermined operating condition is satisfied, the detected AC of the commercial power system 12 is detected as shown in FIG. The power generation device 20 is driven to output AC power having the same phase as the power phase, that is, to perform synchronous operation, and the process proceeds to S38 to turn on the second switch 34e. Thereby, both the electric power of the commercial power system 12 and the electric power of the power generator 20 are supplied to the electric load 14.

  As described above, the cogeneration apparatus 10 according to the first embodiment includes the generator 32 connected to the first power supply path 16 of the AC power from the commercial power system 12 to the electric load 14, and A first switch 24 disposed in the first power supply path 16 is provided, and when a power failure is detected in the commercial power system 12, the first switch 24 is turned off to supply power from the generator 32 to the commercial power system 12. Since the supply is cut off, it is possible to reliably prevent the reverse power flow in which the power output from the cogeneration apparatus 10 flows into the commercial power system 12 when the commercial power system 12 fails.

  In addition, a battery 60 for storing DC power is provided, and after the power supply from the generator 32 to the commercial power system 12 is cut off, the battery 60 is replaced with the inverter circuit 34c of the generator 32 (more precisely, the inverter circuit 34c). Since it is connected to the step-up circuit 34b) arranged on the input side and the output of the generator 32 and the output of the battery 60 are converted into AC power and supplied to the electric load 14, it should be supplied to the electric load 14. The power can be increased by the amount of power output from the battery 60. Thereby, even when the electrical load exceeds the original maximum output of the cogeneration apparatus 10, if the excess is within the range of the output of the battery 60, the necessary power can be supplied to the electrical load 14.

  In addition, when the load does not exceed the original maximum output of the cogeneration apparatus 10, even when an instantaneous overload occurs due to an inrush current, power can be stably supplied to the electric load 14.

  Further, since the battery 60 is connected to the starter (generator 32) of the engine 30 when starting the generator 32 during a power failure, the engine 30 can be reliably started by the battery 60. Further, for example, in a cogeneration apparatus that already has a battery for starting the engine, the power to be supplied to the electric load 14 can be increased simply by connecting the battery to the inverter circuit 34c at the time of a power failure. It becomes possible. That is, the power to be supplied to the electric load 14 can be increased without providing a new battery.

  Next, a cogeneration apparatus 10 according to a second embodiment of the present invention will be described.

  Hereinafter, a description will be given focusing on differences from the first embodiment. In the second embodiment, a voltage sensor is connected to the power line connected to the second feeding path 44 as shown by an imaginary line in FIG. 70 is connected, and a signal corresponding to the voltage of the second power supply path 44, that is, the output voltage of the inverter circuit 34c, is output to the ECU 50.

  FIG. 5 is a flow chart similar to a part of the flow chart of FIG. 2 partially showing the operation of the cogeneration apparatus according to the second embodiment. FIG. 6 is a time chart similar to FIG. 4 showing the output voltage of the generator 32 (more precisely, the inverter circuit 34c) and the DC / DC converter unit 64.

  In the following, in the second embodiment, the process proceeds from S22 to S23a, and the output value of the voltage sensor 70, that is, the output voltage Vi of the inverter circuit 34c is read (detected). Then, the process proceeds to S24a to determine whether or not the detected output voltage Vi is less than a first predetermined value (predetermined value). The first predetermined value is set to a value indicating a state in which the operation load amount of the electric load 14 is increased to be in an overload state and the power generation device 20 needs to be backed up by the battery 60, for example, AC 190V.

  When the result in S24a is affirmative and it is determined that the power generation apparatus 20 needs to be backed up by the battery 60 (time tc in FIG. 6), the process proceeds to S25a to turn on the third switch 64d of the DC / DC converter unit 64. Thereby, the output of the battery 60 boosted to DC 270 V by the first DC / DC converter 64a is supplied to the booster circuit 34b (in other words, the input side of the inverter circuit 34c) via the third switch 64d and the changeover switch 66. To be supplied.

  As described above, when the detected output voltage Vi of the inverter circuit 34 c is less than the first predetermined value, the battery 60 is connected to the inverter circuit 34 c of the generator 32. If the result in S24a is negative, the process in S25a is skipped.

  Next, in S26a, it is determined whether or not the output voltage Vi of the inverter circuit 34c has exceeded a second predetermined value. Specifically, the overload state is eliminated by performing backup by the battery 60 in S25a, and the output voltage of the generator 32, that is, the output voltage Vi of the inverter circuit 34c is gradually increased, and backup by the battery 60 is performed. It is determined whether or not a voltage value (second predetermined value) indicating a state not required is exceeded. Accordingly, the second predetermined value is set to a value larger than the first predetermined value (for example, AC 200V).

  When the result in S26a is affirmative and the generator 32 no longer requires backup by the battery 60 (time td in FIG. 6), the process proceeds to S27a, and the third switch 64d of the DC / DC converter unit 64 is turned off. Thereby, the power supply from the battery 60 to the inverter 34 is cut off (the backup by the battery 60 is terminated).

  Next, the process proceeds to S28a to determine whether or not the commercial power system 12 has been restored (whether the power failure has been completed). When the result in S28a is negative, the process returns to S23a, and the above process is repeated. When the result is positive, the process proceeds to S28 described above, and the third switch 64d of the DC / DC converter unit 64 is turned off. Thereby, the power supply from the battery 60 to the inverter 34 is completely cut off.

  Thus, in the cogeneration apparatus 10 according to the second embodiment, the output voltage Vi of the inverter circuit 34c is detected, and when the detected voltage is less than the first predetermined value, the battery 60 is connected to the inverter circuit 34c. Therefore, the battery 60 outputs to the inverter circuit 34 only when the output voltage of the inverter circuit 34c decreases due to an increase in the operation load amount of the electric load 14, and the power consumption of the battery 60 is reduced. Can be reduced.

  The remaining configuration and effects are not different from those of the first embodiment.

  Next, a cogeneration apparatus 10 according to a third embodiment of the present invention will be described.

  FIG. 7 is a block diagram similar to FIG. 1 showing the entire cogeneration apparatus according to the third embodiment.

  The following description focuses on the differences from the first embodiment. In the third embodiment, as shown in FIG. 7, the starter motor 80 is provided as a starting device for the engine 30, and the generator 32a is an alternating current. Only a function as a generator (alternator) that outputs electric power is provided. Further, the changeover switch 66 is removed, the battery 60 is connected to the starter motor 80 through a power line (not shown), and the third switch 64d of the DC / DC converter unit 64 is directly connected to the booster circuit 34b of the inverter 34. Configured.

  Therefore, when starting the engine 30 and driving the power generation apparatus 20 in S20 of FIG. 2 or the like, the DC voltage output from the battery 60 is supplied to the starter motor 80 via the power line, and the starter motor 80 is driven. To crank the engine 30 and start it.

  As described above, in the cogeneration apparatus 10 according to the third embodiment, the starter motor of the engine 30 is replaced with the generator 32 (specifically, the starter generator) of the first and second embodiments. Since it is configured to include 80, the engine 30 can be started more reliably by the battery 60.

  The remaining configuration and effects are not different from those of the previous embodiments.

  As described above, in the first to third embodiments of the present invention, the generator 32 connected to the AC power feed path (first feed path) 16 from the commercial power system 12 to the electrical load 14, 32a and the internal combustion engine (engine 30) that drives the generator, and in the cogeneration device 10 that supplies exhaust heat of the internal combustion engine to a heat load (hot water storage tank) 42, a battery 60 that stores DC power; When a power failure is detected in the switch (first switch 24) arranged in the power supply path and the commercial power system 12, the switch is turned off to supply power from the generator 32 to the commercial power system 12. After the power supply interruption means (current / voltage sensor 52. S10, S16) to be cut off and the power supply from the generator 32 to the commercial power system 12 are cut off, the battery 6 Is connected to the inverter circuit 34c of the generator 32, and battery connecting means (ECU 50, S24, S25a) for converting the output of the generator 32 and the output of the battery 60 into alternating current power and supplying it to the electric load 14 is provided. It was configured to provide.

  Further, in the second embodiment, voltage detecting means (voltage sensor 70, S23a) for detecting the output voltage Vi of the inverter circuit 34c is provided, and the battery connecting means is configured such that the detected voltage Vi is a predetermined value. When the value is less than the first predetermined value, the battery is connected to the inverter circuit (S24a, S25a).

  In the first to third embodiments, the battery connecting means is configured to connect the battery to the starter of the internal combustion engine when starting the generator 32 (S20).

  In addition, the internal combustion engine starter is configured to include either the generator 32 or the starter motor 80.

  In the above description, when the power failure of the commercial power system 12 is not detected, the engine 30 is started and the power generator 20 is driven. However, depending on the usage status of the electric load 14 and the heat load (hot water storage tank 42). The power generation device 20 may be driven.

  Further, in the above-described embodiment, the phase of the AC power output from the commercial power system 12 is detected, and the power generation device 20 is driven so as to output the AC power having the same phase as the detected phase. You may drive the electric power generating apparatus 20 so that it may become the same to a voltage.

  In the above-described embodiment, the engine using gasoline fuel is used as the drive source (engine 30) of the power generation apparatus 20, but a gas engine using city gas / LP gas as fuel may be used.

  The AC power output from the commercial power system 12 is 100 / 200V. However, when the AC power output from the commercial power system exceeds 100 / 200V, the corresponding voltage is output from the power generator 20. Not too long.

  Moreover, although the maximum power generation output of the generator 32 or the displacement of the engine 30 is shown as a specific value, it goes without saying that these are examples and not limited.

1 is a block diagram generally showing a cogeneration apparatus according to a first embodiment of the present invention. It is a flowchart showing operation | movement of the cogeneration apparatus shown in FIG. It is a time chart explaining the synchronous operation of the electric power generating apparatus shown in FIG. 2 is a time chart showing output voltages of a three-phase bridge circuit and a DC / DC converter section shown in FIG. 1. It is a flowchart similar to a part of FIG. 2 flowchart which partially shows operation | movement of the cogeneration apparatus which concerns on 2nd Example of this invention. FIG. 5 is a time chart similar to FIG. 4 showing output voltages of the inverter circuit and the DC / DC converter section shown in FIG. 1. It is the same block diagram as FIG. 1 which shows the cogeneration apparatus based on 3rd Example of this invention generally.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Cogeneration apparatus, 12 Commercial power system, 14 Electric load, 16 1st electric power feeding path (power feeding path), 24 1st switch (switch), 30 Engine (internal combustion engine) 32, 32a Generator, 34c Inverter circuit, 50 ECU (Electronic Control Unit), 52 Current / Voltage Sensor, 60 Battery, 70 Voltage Sensor, 80 Starter Motor

Claims (4)

In a cogeneration apparatus that includes a generator connected to an AC power supply path from a commercial power system to an electric load and an internal combustion engine that drives the generator, and supplies exhaust heat of the internal combustion engine to a heat load.
a. A battery for storing DC power,
b. A switch disposed in the power supply path,
c. When a power failure of the commercial power system is detected, power supply shut-off means for shutting off the power supply from the generator to the commercial power system by turning off the switch;
And d. After the power supply from the generator to the commercial power system is cut off, the battery is connected to an inverter circuit of the generator, and the output of the generator and the output of the battery are converted into AC power to convert the electric power Battery connection means for supplying to the load,
A cogeneration system characterized by comprising: e. Voltage detection means for detecting an output voltage of the inverter circuit;
2. The cogeneration apparatus according to claim 1, wherein the battery connection unit connects the battery to the inverter circuit when the detected voltage is less than a predetermined value.   3. The cogeneration apparatus according to claim 1, wherein the battery connection unit connects the battery to a starter of the internal combustion engine when starting the generator. 4.   4. The cogeneration apparatus according to claim 3, wherein the starting device for the internal combustion engine is one of the generator and the starter motor.

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