JP4535392B2 - Cogeneration system - Google Patents

Description

  The present invention relates to a cogeneration system that supplies generated power from a combined heat and power supply device to an electric load, and collects exhaust heat from the combined heat and power supply device and stores it as hot water.

  In recent years, cogeneration systems using electric power and heat have been proposed and put into practical use in order to effectively use energy and increase its efficiency. This cogeneration system is connected to a power supply line for supplying power from a commercial power supply to a power load and a power supply line for supplying power from a commercial power supply to the power supply line. And an electric power measuring means for measuring electric power in the electric power supply line, and electric power from the inverter and the commercial power source is supplied to the electric power load via the electric power supply line (for example, a patent) Reference 1).

  At the time of operating power generation where the combined heat and power supply is performed, the power measuring means measures the load power of the power load and detects the occurrence of a reverse power flow to the commercial power source. The load power measured by this power measuring means is used for operation control of the combined heat and power unit, and based on the measurement result of the load power, predicted load data for the operation of the combined heat and power unit is created, and this reverse power flow Based on the detection result of the occurrence of this, the electric power supplied from the combined heat and power supply device to the power supply line via the inverter is controlled so that a reverse power flow does not occur. In addition, during standby for operating power generation when the combined heat and power supply is not performed, detection of reverse power flow is not detected, and only load power measurement is performed.

JP 2004-48838 A

  The conventional cogeneration system as described above has the following problems. Since the power measurement means is required to have high measurement accuracy when detecting the occurrence of reverse power flow, the power measurement means is composed of, for example, a microcomputer with high arithmetic processing capability. Power consumption is relatively large. However, at the time of standby power generation of a combined heat and power unit that does not detect the occurrence of reverse power flow, high measurement accuracy of the power measuring means when measuring load power is not required, and in such a case, the power measuring means is not loaded. If the power is measured with high accuracy, the standby power of the power measuring means increases, and there is a problem that the total energy saving effect of the cogeneration system is reduced.

  The objective of this invention is providing the cogeneration system which can reduce the standby electric power at the time of the active power generation standby of a cogeneration apparatus.

The cogeneration system according to claim 1 of the present invention includes a cogeneration device that generates electric power and heat, an electric power supply line for supplying electric power from a commercial power source to an electric load, and power generation from the cogeneration device. An inverter for systematic connection of power to the power supply line, and a cogeneration system in which power from the inverter and the commercial power supply is supplied to the power load via the power supply line,
A first power measuring means for measuring the power in the power supply line with high accuracy; and a second power measuring means for measuring the power in the power supply line with low precision.
At the time of standby for operation power generation of the combined heat and power supply device, the second power measurement unit is activated, while the first power measurement unit is deactivated, and the second power measurement unit measures the power in the power supply line with low accuracy. In addition, during the operation power generation of the combined heat and power supply device, the first power measurement unit is activated, while the second power measurement unit is deactivated, and the first power measurement unit accurately calculates the power in the power supply line. It is characterized by measuring with.

Moreover, in the cogeneration system according to claim 2 of the present invention, a combined heat and power device that generates power and heat, a power supply line for supplying power from a commercial power source to a power load, and the combined heat and power device And an inverter for systematically connecting the generated power to the power supply line, and the power from the inverter and the commercial power supply is supplied to the power load via the power supply line. And
A first power measuring means for measuring the power in the power supply line with high accuracy; and a second power measuring means for measuring the power in the power supply line with low precision.
At the time of standby for operating power generation of the combined heat and power supply device, the second power measuring unit is activated, while the first power measuring unit is deactivated, and the second power measuring unit measures the power in the power supply line with low accuracy. In addition, during the operation power generation of the combined heat and power supply device, the first power measurement unit and the second power measurement unit are respectively operated, and the first power measurement unit measures the power in the power supply line with high accuracy, The second power measuring means measures the power in the power supply line with low accuracy.

  Furthermore, in the cogeneration system according to claim 3 of the present invention, the first power measuring means detects a current in the power supply line and a voltage in the power supply line. And a first power calculation means for calculating power in the power supply line based on a detection voltage of the voltage detection means and a detection current of the current detection means. (2) The power measurement means includes the current detection means, a storage means for storing the detection voltage of the voltage detection means, a detection voltage of the voltage detection means and a detection current of the current detection means stored in the storage means. And a second power calculating means for calculating power in the power supply line based on the above.

  Moreover, in the cogeneration system according to claim 4 of the present invention, the first power measurement means detects a current in the power supply line and a voltage in the power supply line. And a first power calculation means for calculating power in the power supply line based on a detection voltage of the voltage detection means and a detection current of the current detection means. 2 The power measurement means is based on the current detection means, a simple voltage detection means for detecting a voltage in the power supply line, a voltage detected by the simple voltage detection means, and a detection current of the current detection means. It is comprised from the 2nd electric power calculating means for calculating electric power, It is characterized by the above-mentioned.

  Furthermore, in the cogeneration system according to claim 5 of the present invention, the second power measuring means includes a storage means for storing a detection voltage of the voltage detection means, and the voltage detection stored in the storage means. Voltage correction means for correcting the voltage detected by the simple voltage detection means based on the detection voltage of the means.

  In the cogeneration system according to claim 6 of the present invention, a heat recovery hot water storage device for recovering the heat generated from the cogeneration device and storing it as hot water in relation to the cogeneration device, and the heat A drive power supply device for supplying drive power to the recovery hot water storage device, and the second power measurement means is supplied with a part of the drive power from the drive power supply device. To do.

  According to the cogeneration system of the first aspect of the present invention, during standby operation of a cogeneration apparatus that does not require high measurement accuracy, power is measured with low accuracy (that is, power consumption is relatively small). While the second power measuring means operates, the first power measuring means for measuring the power with high accuracy (that is, relatively large power consumption) stops operating, so that the cogeneration apparatus is in the standby state for standby power generation. The standby power of the generation system can be reduced, and the operation efficiency of the entire cogeneration system can be increased. At the time of operation power generation standby, it is only necessary to measure the power consumed by the power load, and high-accuracy measurement is not required, and sufficient measurement values can be obtained by power measurement by the second power measurement means. In addition, during the operation and power generation of the combined heat and power device that requires high measurement accuracy, the first power measurement unit is activated while the second power measurement unit is deactivated. Therefore, the first power measurement unit reversely flows into the commercial power source. Can be detected with high accuracy, and the reliability of the cogeneration system can be improved. At this time, the power consumption at the power load is obtained by the first power measuring means.

  Moreover, according to the cogeneration system according to claim 2 of the present invention, the second power measuring means for measuring the power with low accuracy is activated during standby operation of the combined heat and power supply apparatus that does not require high measurement accuracy. On the other hand, since the first power measuring means for measuring the power with high accuracy is stopped, the standby power of the cogeneration system during the standby operation of the cogeneration system can be reduced, and the entire cogeneration system can be operated. Efficiency can be increased. In addition, since the first and second power measuring means operate during the operation power generation of the combined heat and power supply unit that requires high measurement accuracy, the first power measuring means can accurately generate the reverse power flow to the commercial power source. It can be detected and the reliability of the cogeneration system can be improved. At this time, the measurement value obtained by the first power measurement means is used for determination of reverse power flow and the power consumption at the power load is obtained by the second power measurement means.

  Further, according to the cogeneration system according to claim 3 of the present invention, the second power measurement means is stored in the current detection means, the storage means for storing the detection voltage of the voltage detection means, and the storage means. Second power calculating means for calculating power based on the detected voltage and the detected current of the current detecting means, the second power measuring means measures the power by the first power measuring means. The electric power is measured by using the detection voltage of the voltage detection means at the time, whereby the configuration of the second electric power measurement means becomes relatively simple and the power consumption can be reduced, and the operation of the cogeneration device is performed. The standby power of the cogeneration system during power generation standby can be further reduced.

  Moreover, according to the cogeneration system according to claim 4 of the present invention, the second power measuring means includes the current detecting means, the simple voltage detecting means for detecting the voltage in the power supply line, and the detection. Since the second power calculating means for calculating the power based on the voltage and the detected current of the current detecting means, the second power measuring means uses the voltage detected by a relatively simple method. Thus, the power generation can be measured, whereby the configuration of the second power measuring means becomes relatively simple and the power consumption can be reduced, and the cogeneration system at the time of standby operation of the combined heat and power supply device Standby power can be further reduced.

  Furthermore, according to the cogeneration system according to claim 5 of the present invention, the second power measuring means is based on the storage means for storing the detection voltage of the voltage detection means and the detection voltage stored in the storage means. And a voltage correcting means for correcting the voltage detected by the simple voltage detecting means, so that the measured power value by the second power measuring means and the measured power value by the first power calculating means The error can be corrected, and thereby the power measurement accuracy by the second power measuring means can be increased.

  According to the cogeneration system according to claim 6 of the present invention, the second power measuring means is supplied with part of the drive power from the drive power supply device for supplying drive power to the heat recovery hot water storage device. Therefore, the second power measuring means is driven by this driving power, so that the driving power from the driving power supply device can be used effectively, and the operating efficiency of the cogeneration system can be increased.

Hereinafter, various embodiments of a cogeneration system according to the present invention will be described with reference to the accompanying drawings.
First Embodiment First, a cogeneration system according to a first embodiment will be described with reference to FIGS. FIG. 1 is a block diagram schematically showing a cogeneration system according to the first embodiment of the present invention, and FIG. 2 is a block diagram schematically showing a control system of the cogeneration system of FIG. 3 is a flowchart showing a control flow of the cogeneration system of FIG.

  In FIG. 1, a cogeneration system 2 according to the first embodiment includes a cogeneration device 4 that generates electric power and heat, and a heat recovery hot water storage device 6 that recovers heat generated from the cogeneration device 4 and stores it as hot water. And a power supply line 12 for supplying power from the commercial power supply 8 to the power load 10 and an inverter 14 for systematically connecting the generated power from the cogeneration apparatus 4 to the power supply line 12. Yes.

  The cogeneration device 4 is composed of a combination of an engine 16 such as a gas engine or a diesel engine and a power generation device 18 driven by the engine 16, and electric power and heat are generated from the cogeneration device 4. . The power generation device 18 is drivingly connected to the output shaft 20 of the engine 16, and when the engine 16 is driven, the rotational driving force from the engine 16 is transmitted to the power generation device 18 via the output shaft 20. Operates to generate generated power. The engine 16 is provided with a fuel supply valve 22 for controlling the amount of fuel supplied to the engine 16, and the opening degree of the fuel supply valve 22 is adjusted in the output increasing direction (opening direction). Then, the generated power of the power generator 18 increases, and the generated power of the power generator 18 decreases when the opening of the fuel supply valve 22 is adjusted in the output decreasing direction (closing direction).

  The cogeneration device 4 further includes a cooling water circulation passage 24 for circulating the cooling water from the engine 16, and a cooling water circulation pump 26 is disposed in the cooling water circulation passage 24. Due to the action, the cooling water is circulated through the cooling water circulation passage 24.

  The heat recovery hot water storage device 6 includes a hot water storage tank 28 for storing hot water, a circulation flow path 30 for circulating water (or hot water) in the hot water storage tank 28, and a circulation pump 32 disposed in the circulation flow path 30. The water (or hot water) stored in the hot water storage tank 28 is circulated through the circulation channel 30 by the action of the circulation pump 32. A heat exchanger 34 is disposed between the cooling water circulation passage 24 of the combined heat and power supply device 4 and the circulation passage 30 of the heat recovery hot water storage device 6. In this heat exchanger 34, the cooling water circulation passage 24 is connected to the cooling water circulation passage 24. Heat exchange is performed between the flowing cooling water and the water (or hot water) flowing through the circulation flow path 30. When heat exchange is performed in this manner, the exhaust heat from the engine 16 is stored in the hot water storage tank 28 as hot water via the cooling water flowing through the cooling water circulation passage 24 and the water (or hot water) flowing through the circulation passage 30.

  A water supply line 36 for supplying water is connected to the hot water storage tank 28. One end of the water supply line 36 is connected to the hot water storage tank 28, and the other end is connected to a water supply source (not shown) such as a water pipe. The water supply line 36 is provided with a pressure reducing check valve 38, and the pressure reducing check valve 38 prevents hot water from flowing backward from the hot water storage tank 28 toward the water supply line 36. The hot water storage tank 28 is further connected with a hot water supply line 40 for supplying hot water. One end of the hot water supply line 40 is connected to the hot water storage tank 28, and the other end is connected to one or a plurality of curans (not shown). When the curan is opened, the hot water in the hot water storage tank 28 is heated. Is discharged through the hot water supply line 40.

  In addition, a drive power supply device (not shown) is provided in association with the heat recovery hot water storage device 6, and drive power from the drive power supply device is supplied to the circulation pump 32 and the like, and the circulation pump 32 and the like are driven by this drive power. Is driven.

  The generator 14 of the combined heat and power supply device 4 is electrically connected to the input side of the inverter 14, and the power load 10 is electrically connected to the output side of the inverter 14 via the power supply line 12. The inverter 14 converts the generated power from the power generator 18 of the combined heat and power supply device 4 into predetermined AC power (AC power similar to AC power from the commercial power supply 8, for example, 100V, 60 Hz single-phase AC power). Convert. Further, the AC power from the inverter 14 is connected to the power supply line 12, whereby the AC power from the commercial power supply 8 and the inverter 14 is supplied to the power load 10, respectively. Is consumed. The power load 10 is composed of, for example, an air conditioner, various mechanical devices, or a lighting device installed in a general home or factory.

  Referring also to FIG. 2, the cogeneration system 2 further includes generated power detection means 42 for detecting the generated power of the combined heat and power supply device 4 and power in the power supply line 12 (that is, load power of the power load 10). ) With high accuracy, first power measurement means 44 for measuring power in the power supply line 12 with low accuracy, cogeneration apparatus 4, and first and second power. And control means 48 for controlling the measuring means 44 and 46, respectively. The generated power detection means 42 is composed of, for example, a wattmeter and the like, and detects the generated power over the operation of the cogeneration apparatus 4 for example.

  The first power measurement unit 44 includes a current detection unit 50 for detecting a current flowing through the power supply line 12, a voltage detection unit 52 for detecting a voltage in the power supply line 12, and a detection current of the current detection unit 50. And first power calculation means 54 for calculating the power in the power supply line 12 based on the detected voltage of the voltage detection means 52, and the power in the power supply line 12 is measured with high accuracy. The electric power measured by the first electric power measuring means 44 is used for determining the load power data of the electric power load 10 and the occurrence of reverse power flow to the commercial power supply 8. The first power calculation means 54 is constituted by, for example, a microcomputer having a high calculation processing capability, and the calculation of power by the first power calculation means 54 is performed as follows, for example. Assuming that the detection voltage of the voltage detection means 52 is v (t) and the detection current of the current detection means 50 is i (t), the first power calculation means 54 uses the detection voltage v (t) and the detection current i (t). ) Is integrated as required to calculate the power W. That is, the power W in the power supply line 12 is calculated using the following formula (1), and the calculation of the power W using the formula (1) has high measurement accuracy. Therefore, the first power measurement is performed. The power consumption of the means 44 is relatively large.

なお、この数式（１）において、Ｔは電力供給ライン１２における検知電圧の電圧波形（正弦波形）の周期である。また、この第１電力計測手段４４には、インバータ１４からの電力の一部が電力供給ライン１２を介して供給され、発電装置１８の発電電力を利用して第１電力計測手段４４が駆動される。

In Equation (1), T is the period of the voltage waveform (sine waveform) of the detected voltage in the power supply line 12. In addition, a part of the power from the inverter 14 is supplied to the first power measuring means 44 via the power supply line 12, and the first power measuring means 44 is driven using the generated power of the power generator 18. The

The second power measuring unit 46 includes the current detecting unit 50 described above, a storage unit 56 for storing the detection voltage of the voltage detecting unit 52, a detection current of the current detecting unit 50, and a voltage detection stored in the storage unit 56. Second power calculating means 58 for calculating the power in the power supply line 12 based on the detection voltage of the means 52, and by measuring the power in the power supply line 12, the load of the power load 10 Measure power with low accuracy. The second power calculation means 58 is composed of, for example, a microcomputer having a low calculation processing capability, and the power calculation by the second power calculation means 58 is performed as follows, for example. Assuming that the detection voltage of the voltage detection means 52 stored in the storage means 56 is v _m (t) and the detection current of the current detection means 50 is i (t), the second power calculation means 58 uses the detection voltage v _m ( t) and the detected current i (t) are integrated as required. That is, in the above equation (1), v (t) is replaced with v _m (t) to calculate power. To do. Thus, since the second power calculation means 58 calculates the power using the detection voltage of the voltage detection means 52, the configuration of the second power measurement means 46 becomes relatively simple, and therefore the consumption thereof The power is relatively small. Further, a part of the driving power from the driving power supply device is supplied to the second power measuring means 46, and the second power measuring means 46 is driven by this driving power. In addition, although the current detection means 50 of the 1st electric power measurement means 44 and the current detection means 50 of the 2nd electric power measurement means 46 are used in common, you may make it use a different thing.

  The control unit 48 includes, for example, a microcomputer, and includes a memory 60, a data calculation unit 62, a control signal generation unit 64, a reverse power flow determination unit 66, a switching signal generation unit 70, and a communication unit 72.

  The memory 60 stores the power load 10 measured by the first and second power measuring means 44 and 46 as past load data. The data calculation means 62 calculates the predicted load data on the operation day by processing the past load data stored in the memory 60 as required in order to set the operation operation schedule of the combined heat and power supply device 4, as will be described later. Thus, the combined heat and power supply apparatus 4 is controlled based on the calculated predicted load data. The calculated predicted load data is stored in the memory 60.

  Based on the predicted load data stored in the memory 60, the control signal generation unit 64 generates a power decrease signal when the load power decreases, and generates a power increase signal when the load power increases. When the power lowering signal is generated, the control unit 48 adjusts the opening degree of the fuel supply valve 22 in the output lowering direction to lower the generated power of the combined heat and power supply device 4, and when the power increasing signal is generated, Adjusting the opening of the fuel supply valve 22 in the direction of increasing output increases the power generated by the combined heat and power supply device 4, thereby matching the fluctuation pattern of the load power of the power load 10 (for example, lifestyle patterns at home, etc.) Thus, the operation of the cogeneration apparatus 4 is controlled.

  The reverse power flow determination unit 66 generates a reverse power flow determination signal when the first power measurement unit 44 detects a reverse power flow to the commercial power supply 8. When the reverse power flow determination signal is generated in this way, the control signal generation unit 64 generates a power reduction signal, and the control unit 48 adjusts the opening of the fuel supply valve 22 in the output reduction direction based on the power reduction signal. Thus, the generated power of the combined heat and power supply device 4 is reduced, thereby preventing the occurrence of reverse power flow.

  Based on the detection signal from the generated power detection means 42, the switching signal generation means 70 generates a first switching signal in an operation power generation standby state where the power generation by the combined heat and power supply device 4 is not performed, and the power generation by the combined heat and power supply device 4. A second switching signal is generated in the operating power generation state in which is performed. When the first switching signal is generated, the supply of power from the inverter 14 to the first power measuring means 44 is stopped, whereby the first power measuring means 44 is deactivated, and the driving power from the drive power supply device is reduced. The second power measuring means 46 is operated by being supplied to the second power measuring means 46. Further, when the second switching signal is generated, the power from the inverter 14 is supplied to the first power measuring means 44 so that the first power measuring means 44 is operated, and the driving power supply device supplies the second power measuring means. When the supply of drive power to 46 is stopped, the operation of the second power measuring means 46 is stopped.

  The communication means 72 is for transmitting and receiving various data between the control means 48 and the first and second power measuring means 44, 46. For example, from the first and second power measuring means 44, 46, Load power data and the like are received by the control means 48 by the communication means 72, and the first and second switching signals from the switching signal generating means 70 are received by the communication means 72 by the first and second power measuring means 44. , 46 respectively. By controlling in this way, the second power measuring means 46 is operated in an electric system separate from the electric system of the combined heat and power supply device 4.

  Next, the flow of control of the cogeneration system 2 will be described with reference to FIG. When the operation of the cogeneration system 2 is started, the process proceeds from step S1 to step S2, and the switching signal generating means 70 generates a first switching signal (step S2), and the second power measuring means is based on the first switching signal. 46 operates (step S3). Thus, the second power measuring unit 46 is based on the detected current of the current detecting unit 50 and the detected voltage of the voltage detecting unit 52 stored in the storage unit 56 (stored in the previous operation operation). The power is calculated, and the load power of the power load 10 is measured in this way (step S4), and the measured load power is stored in the memory 60 as past load data. This load power measurement is performed until the combined heat and power supply device 4 is operated.

  When the operation of the cogeneration device 4 is started, the process proceeds from step S5 to step S6, the power generation device 18 is driven by the engine 16, and the generated power generated in the power generation device 18 is supplied to the inverter 14, and this inverter 14 After being converted into predetermined AC power at, it is supplied to the power load 10 through the power supply line 12 together with the AC power from the commercial power supply 8 and is consumed by the power load 10.

  When the cogeneration apparatus 4 is operated, the switching signal generating unit 70 generates a second switching signal (step S6), and the first power measuring unit 44 is operated based on the second switching signal, while the second power measuring unit is operated. 46 stops operating (step S7). Thus, the first power calculation means 54 calculates the power in the power supply line 12 as described above based on the detection current of the current detection means 50 and the detection voltage of the voltage detection means 52. As a result, the first power measuring means 44 measures the load power of the power load 10, and the reverse power flow determining means 66 of the control means 48 determines the occurrence of reverse power flow to the commercial power supply 8 using this measured power. (Step S8). The load power of the power load 10 measured by the first power measuring means 44 is stored as past load data in the memory 60 of the control means 48, and the detected voltage of the voltage detecting means 52 is stored in the second power measuring means 46. 56.

  If the generated power from the combined heat and power supply device 4 becomes larger than the load power of the power load 10 during the operation of the combined heat and power supply device 4, the surplus power generated is reversely flowed to the commercial power supply 8. When a tidal current is likely to occur, the process proceeds from step S9 to step S10, where the reverse power flow determination means 66 determines that a reverse power flow has occurred and generates a reverse power flow determination signal. Then, based on this reverse power flow determination signal, the control signal generation means 64 generates a voltage drop signal (step S11), and the control means 48 reduces the generated power of the combined heat and power supply device 4 below the load power of the power load 10. (Step S12), thereby preventing the occurrence of reverse power flow. As described above, since the first power measuring means 44 detects the load power of the power load 10 with high accuracy, the occurrence of the reverse power flow to the commercial power supply 8 is detected, so that the generation of the reverse power flow is reliably determined. Can do.

  When the operation of the combined heat and power supply apparatus 4 is stopped, the process proceeds from step S13 to step S14, and the switching signal generation unit 70 generates a first switching signal. Based on the first switching signal, the second power measurement unit 46 The first power measuring means 44 is deactivated (step S15). In this way, as described above, the second power calculation unit 46 performs the power operation as described above based on the detection current of the current detection unit 50 and the detection voltage of the voltage detection unit 52 stored in the storage unit 56. Thus, the second power measuring means 46 measures the load power of the power load 10 (step S16). The measured load power is stored in the memory 60 as past load data, and such a power load measurement is performed while the combined heat and power supply device 4 is on standby for power generation.

  Thereafter, when the combined heat and power supply device 4 is operated, the process returns from step S17 to step S6, and the above-described control is performed. As described above, in the cogeneration system 2 of the first embodiment, the second power measuring means 46 with relatively small power consumption is operated during standby for operation power generation of the combined heat and power supply device 4, while comparing the power consumption. Since the first large power measuring means 44 is deactivated, the standby power of the cogeneration system 2 can be reduced at the time of standby for operating power generation, and the operating efficiency can be increased.

Second Embodiment Next, a cogeneration system according to a second embodiment will be described with reference to FIG. FIG. 4 is a block diagram schematically showing a control system of the cogeneration system according to the second embodiment of the present invention. Note that in the following embodiments, substantially the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the cogeneration system 2A of the second embodiment, the second power measuring means 46A is composed of a current detecting means 50, a zero cross detecting means 74, a voltage calculating means 76, and a second power calculating means 58A. In the present embodiment, the zero cross detection means 74 and the voltage calculation means 76 constitute a simple voltage detection means for simply detecting a voltage in a power supply line (not shown). Also in the second embodiment, as in the first embodiment, the current detection unit 50 is commonly used for the first and second power measurement units 44 and 46A. May be used separately.

The zero cross detecting means 74 detects a zero cross of a voltage waveform (sine waveform) in the power supply line, and calculates a period T of the voltage waveform from the detected zero cross. The voltage calculation means 76 includes a rectifying / smoothing circuit (not shown) for rectifying and smoothing the voltage waveform in the power supply line (not shown). The voltage waveform in the power supply line is rectified by this rectifying / smoothing circuit. Based on the voltage constant V _c (for example, 100 V) obtained by smoothing and the period T calculated by the zero cross detection means 74, the voltage V _o in the power supply line is calculated. That is, the voltage V _o in the power supply line is calculated using the following formula (2).

第２電力演算手段５８Ａは、このようにして演算された電圧Ｖ_ｏと電流検知手段５０の検知電流ｉ（ｔ）とに基づき、電力供給ラインにおける電力を演算する。すなわち、電力供給ラインにおける電力Ｗは、下記の数式（３）を用いて演算される。

Second power computing means 58A, based on the thus voltage is calculated by the V _o and detecting current of the current detecting means 50 i (t), calculates the power in the power supply line. That is, the power W in the power supply line is calculated using the following formula (3).

このように第２電力演算手段５８Ａは、電圧演算手段７６により比較的簡単な方法で演算された電圧を用いて電力供給ラインにおける電力を演算するので、第２電力計測手段４６Ａの構成が比較的簡単なものになり、それ故に、第２電力計測手段４６Ａの消費電力は比較的小さくなる。

Thus, the second power calculation means 58A calculates the power in the power supply line using the voltage calculated by the voltage calculation means 76 in a relatively simple manner, so that the configuration of the second power measurement means 46A is relatively high. Therefore, the power consumption of the second power measuring unit 46A is relatively small.

  In the cogeneration system 2A of the second embodiment, when the operation of the combined heat and power supply device (not shown) is started, a second switching signal is generated by the switching signal generating means 70, and based on this second switching signal. The first power measuring means 44 and the second power measuring means 46A are operated. The first power measuring means 44 measures the load power used for determining the occurrence of reverse power flow to a commercial power supply (not shown) with high accuracy, and the second power measuring means 46A is used for setting an operation schedule. The load power to be measured is measured with low accuracy as described above. The load power measured by the second power measuring means 46A is stored in the memory 60 as past load data.

  When the operation of the combined heat and power supply is stopped, the first switching signal is generated by the switching signal generating unit 70, and the second power measuring unit 46A is operated based on the first switching signal, while the first power measuring unit 46A operates. The means 44 stops operating, and the second power measuring means 46A continues to measure the load power described above. Therefore, during standby for operation power generation of the combined heat and power supply device, the load power of the power load 10 is measured by the second power measuring means 46A with relatively small power consumption, so the same effect as the first embodiment is achieved. Is done.

In the present embodiment, the voltage calculation unit 76 is configured so as to calculate the voltage using the voltage constant V _c obtained by rectifying and smoothing the voltage waveform in the power supply line, thus the voltage Without rectifying and smoothing the waveform, for example, V _c = 100 (V) may be used for a 100 V commercial power supply, and V _c = 200 (V) may be used for a 200 V commercial power supply.

  In the present embodiment, the simple voltage detection means is configured by the zero cross detection means 74 and the voltage calculation means 76. However, such a configuration is merely an example, and the simple voltage detection means can easily calculate the voltage in the power supply line. It can be set as the suitable structure to detect.

Third Embodiment Next, a cogeneration system according to a third embodiment will be described with reference to FIG. FIG. 5 is a block diagram schematically showing a control system of the cogeneration system according to the third embodiment of the present invention.

In the cogeneration system 2B of the third embodiment, the second power measurement unit 46B further includes a storage unit 78 and a voltage correction unit 80 in addition to the configuration of the second power measurement unit 46A of the second embodiment. It is out. The storage unit 78 stores the detection voltage of the voltage detection unit 52 of the first power measurement unit 44. The voltage correction unit 80 corrects the voltage calculated as described above by the voltage calculation unit 76 based on the detection voltage of the voltage detection unit 52 stored in the storage unit 78 as follows, for example. Voltage correcting means 80 corrects the error between the detected voltage v of the voltage detecting means 52 and the stored voltage V _o calculated by the voltage calculation unit 76 in the storage unit 78 (t), the second power computing means 58A is Based on the corrected voltage V _o ′ and the detected current i (t) of the current detection means 50, the power is calculated by replacing the voltage V _o with the corrected voltage V _o ′ using the above equation (3). .

  In the cogeneration system 2B of the third embodiment, as in the second embodiment, when the operation of the combined heat and power supply device (not shown) is started, the switching signal generation means 70 generates the second switching signal. Then, based on the second switching signal, the first power measuring means 44 and the second power measuring means 46B are operated. The first power measuring means 44 measures the power load used for determining the occurrence of reverse power flow to a commercial power supply (not shown) with high accuracy, and the second power measuring means 46B is a load used for setting the operation schedule. Measure power with low accuracy. At this time, the detection voltage of the voltage detection means 52 of the first power measurement means 44 is stored in the storage means 78 of the second power measurement means 46B, and the load power measured by the second power measurement means 46B is the past load. It is stored in the memory 60 as data.

  When the operation of the combined heat and power device is stopped, a first switching signal is generated by the switching signal generating means 70, and the second power measuring means 46B is operated based on the first switching signal, while the first power measuring means is operated. The means 44 stops operating, and the second power measuring means 46B continues to measure the load power described above. In the power measurement by the second power measurement unit 46B, the voltage correction unit 80 sets the voltage calculated by the voltage calculation unit 76 based on the detection voltage of the voltage detection unit 52 stored in the storage unit 78 as described above. The second power measuring means 46B measures the load power of the power load using the corrected voltage in the same manner as in the second embodiment.

  Also in the cogeneration system 2B of the third embodiment, since the load power is measured with low accuracy by the second power measuring means 46B during standby operation of the combined heat and power supply device, the same effects as those of the above embodiments are achieved. In addition, by correcting the voltage calculated by the voltage calculation means 76, the power measurement accuracy by the second power measurement means 46B can be increased, and a highly reliable cogeneration system 2B can be provided. It becomes.

  As described above, the embodiments of various cogeneration systems according to the present invention have been described. However, the present invention is not limited to such embodiments, and various modifications and corrections can be made without departing from the scope of the present invention. .

  For example, in each of the above embodiments, the combined heat and power supply device 4 is configured by a combination of the engine 16 and the power generation device 18, but instead, the combined heat and power supply device 4 may be configured by a fuel cell, for example.

  Further, for example, in each of the above embodiments, the second power measuring means 46A (46B) measures the power by a relatively simple method using the voltage calculated based on the zero cross of the voltage waveform. Instead, for example, the power may be measured by a relatively simple method using the current calculated based on the zero crossing of the current waveform of the current flowing through the power supply line 12.

  Further, for example, in each of the above embodiments, the control means 48 (48A) (48B) is configured to control the generated power of the combined heat and power supply device 4 by adjusting the opening of the fuel supply valve 22 of the engine 16. The power supplied from the thermoelectric generator 4 to the power load 10 may be controlled by controlling the output of the inverter 14 together with the control of the generated power. In this case, the surplus power from the inverter 14 can be configured to be stored as hot water in the heat recovery hot water storage device 6, for example.

  Further, for example, in each of the above-described embodiments, the first power measuring unit 44 measures the load power used for determining the occurrence of the reverse power flow to the commercial power supply 8, but for example, the load for determining the reverse power flow Together with the measurement of electric power, the occurrence of overcurrent in the electric power load 10 may be detected.

  Further, for example, in the second and third embodiments, the first power measuring unit 44 and the second power measuring unit 46A (46B) are respectively operated during the operation power generation of the cogeneration apparatus 4. As in the first embodiment, the first power measuring unit 44 may be operated, while the second power measuring unit 46A (46B) may be stopped. In the first embodiment, the first power measuring means 44 is operated while the second power measuring means 46 is operated while the cogeneration apparatus 4 is operating and generating power. Similarly to the third embodiment, the first power measuring unit 44 and the second power measuring unit 46 may be operated.

  Further, for example, in the above-described embodiment, the reverse power flow is determined by the reverse power flow determination means 66 on the control means 48 (48A) (48B) side using the load power measured by the first power measurement means 44. The reverse power flow determination unit 66 may be included in the first power measurement unit 44 and the first power measurement unit 44 may determine the occurrence of the reverse power flow.

  Further, for example, in each of the above embodiments, the second power measuring means 46 (46A) (46B) is configured to be driven by the driving power from the driving power supply device, but as with the first power measuring means 44, You may comprise so that it may drive with the electric power from the inverter 14. FIG.

1 is a block diagram schematically showing a cogeneration system according to a first embodiment of the present invention. It is a block diagram which shows simply the control system of the cogeneration system of FIG. It is a flowchart which shows the flow of control of the cogeneration system of FIG. It is a block diagram which shows simply the control system of the cogeneration system by the 2nd Embodiment of this invention. It is a block diagram which shows simply the control system of the cogeneration system by the 3rd Embodiment of this invention.

Explanation of symbols

2, 2A, 2B cogeneration system 4 cogeneration system 8 commercial power supply 10 power load 12 power supply line 14 inverter 44 first power measuring means 46, 46A, 46B second power measuring means 50 current detecting means 52 voltage detecting means 54 first 1 power calculation means 56 storage means 58, 58A second power calculation means 74 zero cross detection means 76 voltage calculation means 78 storage means 80 voltage correction means

Claims (6)

A cogeneration device that generates electric power and heat, an electric power supply line for supplying electric power from a commercial power source to an electric power load, and an inverter for systematically connecting the generated electric power from the cogeneration device to the electric power supply line And a cogeneration system in which power from the inverter and the commercial power supply is supplied to the power load via the power supply line,
A first power measuring means for measuring the power in the power supply line with high accuracy; and a second power measuring means for measuring the power in the power supply line with low precision.
At the time of standby for operating power generation of the combined heat and power supply device, the second power measuring unit is activated, while the first power measuring unit is deactivated, and the second power measuring unit measures the power in the power supply line with low accuracy. In addition, during the operation power generation of the combined heat and power supply device, the first power measurement unit is activated, while the second power measurement unit is deactivated, and the first power measurement unit accurately calculates the power in the power supply line. Cogeneration system characterized by measuring with A cogeneration device that generates electric power and heat, an electric power supply line for supplying electric power from a commercial power source to an electric power load, and an inverter for systematically connecting the generated electric power from the cogeneration device to the electric power supply line And a cogeneration system in which power from the inverter and the commercial power supply is supplied to the power load via the power supply line,
A first power measuring means for measuring the power in the power supply line with high accuracy; and a second power measuring means for measuring the power in the power supply line with low precision.
At the time of standby for operation power generation of the combined heat and power supply device, the second power measurement unit is activated, while the first power measurement unit is deactivated, and the second power measurement unit measures the power in the power supply line with low accuracy. In addition, during the operation power generation of the combined heat and power supply device, the first power measuring means and the second power measuring means are respectively operated, and the first power measuring means measures the power in the power supply line with high accuracy, The cogeneration system, wherein the second power measuring means measures the power in the power supply line with low accuracy.   The first power measurement means includes a current detection means for detecting a current flowing through the power supply line, a voltage detection means for detecting a voltage in the power supply line, a detection voltage of the voltage detection means, and the First power calculating means for calculating the power in the power supply line based on the detected current of the current detecting means, and the second power measuring means is the current detecting means and the voltage detecting means. And a second means for calculating the power in the power supply line based on the detection voltage of the voltage detection means and the detection current of the current detection means stored in the storage means. The cogeneration system according to claim 1, wherein the cogeneration system is configured by power calculation means.   The first power measurement means includes a current detection means for detecting a current flowing through the power supply line, a voltage detection means for detecting a voltage in the power supply line, a detection voltage of the voltage detection means, and the First electric power calculation means for calculating electric power in the electric power supply line based on a detection current of the electric current detection means, and the second electric power measurement means includes the electric current detection means and the electric power supply line. Simple voltage detection means for detecting the voltage at the second power calculation means, and second power calculation means for calculating power based on the voltage detected by the simple voltage detection means and the detected current of the current detection means. The cogeneration system according to claim 1, wherein the cogeneration system is provided.   The second power measurement means is detected by the simple voltage detection means based on a storage means for storing a detection voltage of the voltage detection means and a detection voltage of the voltage detection means stored in the storage means. 5. The cogeneration system according to claim 4, further comprising voltage correction means for correcting the voltage.   In relation to the cogeneration device, a heat recovery hot water storage device for recovering the heat generated from the cogeneration device and storing it as hot water, a drive power supply device for supplying drive power to the heat recovery hot water storage device, The cogeneration system according to claim 1, wherein a part of the driving power from the driving power supply device is supplied to the second power measuring unit.

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