JP2005192314A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power converter capable of facilitating identification of a factor at the time of stopping of an apparatus and efficiently and effectively using electric power generated by a solar cell.
SOLUTION: The voltage of DC power generated by a solar cell panel is boosted, the boosted DC voltage is converted into AC voltage, and the solar cell panel is electrically connected to a load system and a commercial power system. A power conversion device that performs system operation, wherein the power conversion device includes a voltage detection unit that detects a voltage of the commercial power system and a memory unit that stores data of the detected voltage, and the memory unit When the abnormality is detected and the interconnection operation is stopped, the voltage data immediately before stopping and the voltage data after a predetermined time after stopping the interconnection operation are stored.
[Selection] Figure 1

Description

  The present invention relates to a power converter that converts DC power obtained from a DC power source such as a solar battery panel into AC power.

  In recent years, a grid-connected system that generates power from a solar cell panel that can photoelectrically convert solar energy into electrical energy, converts the output DC power to AC power using an inverter, and links the solar cell panel to a commercial power system has been put into practical use. Has been.

  FIG. 4 is a schematic configuration diagram showing a configuration of a grid interconnection system in the prior art, and FIG. 5 is a schematic configuration diagram of an example showing a configuration of a power conversion device in the conventional technology.

  As shown in FIG. 4, in the grid connection system in the prior art, solar energy is photoelectrically converted into electric energy by a DC power source 2 constituted by a solar cell panel, and the generated and output DC power is For example, the converter 21 converts the AC voltage into AC power of 200V. Further, the DC power source 2 constituted by the solar battery panel is connected to the commercial power system 12 through the power converter 21.

  As shown in FIG. 5, a conventional power converter 21 includes a booster circuit 23 that boosts and converts a DC voltage of DC power generated by a DC power source 2 constituted by a solar cell panel into a higher DC voltage, and this booster. An inverter circuit 24 that converts the DC power boosted by the circuit 23 into AC power, a control circuit 25 that controls the booster circuit 23 and the inverter circuit 24, a voltage detector 26 that detects the voltage of the commercial power system 12, A current detection unit 27 that detects a current output to the power system, a memory unit 28 that records setting values and abnormal states necessary for control, and the like are connected to the load 13 and the commercial power system 12. Are connected and connected.

  Here, the control circuit 25 operates on the booster circuit 23 and the inverter circuit 24 based on the voltage value and voltage phase signal of the commercial power system 12 obtained from the voltage detector 26 and the output current value obtained from the current detector 27. By controlling the command value, the power conversion circuit 21 can perform an interconnected output synchronized with the commercial power system 12.

On the other hand, in the control circuit 25, when the value detected by the voltage detection unit 26 or the current detection unit 27 is not within the range of the predetermined specified value, the commercial power system 12 or the power conversion device 21 is in an abnormal state. When the determination is made, the booster circuit 23 and the inverter circuit 24 are stopped to control the device. In this case, a method is generally used in which the mode determination of the abnormal state is performed and information such as an error code is stored in the memory unit 28. (For example, see Patent Document 1)
JP 2003-18750 A

  However, in such a conventional method, as described above, the voltage of the commercial power system is detected, and if any abnormality occurs, error information is stored in the memory. This error information is, for example, an error at the time of occurrence of the abnormality. Examples include codes and abnormal occurrence times.

  Moreover, even if it is possible to grasp only the fact that an abnormality has occurred with only these pieces of information, it is not possible to grasp the cause of the abnormality. In other words, in the conventional method, when any abnormality occurs, the main purpose is to stop the device quickly, and the error information is limited to the above-described recording.

  Also, in the occurrence of abnormalities during grid interconnection operation, there are abnormalities caused by the equipment itself and abnormalities caused by the commercial power system, but in the case of abnormalities caused by the commercial power system, the impedance of the distribution system and the surrounding Since it often occurs randomly depending on the equipment operating status, etc., it is particularly difficult to identify the cause. Therefore, there is a problem that even if the device is stopped at a certain error code, it cannot be determined whether the cause of the abnormality is on the commercial power system side or the device side.

  Furthermore, it is difficult to specify the cause of the abnormality for the above reasons, and there is a problem that only the stop of the device is repeated and the generated power during that time cannot be used effectively.

  Therefore, an object of the present invention is made in view of the above-described conventional problems, and makes it easy to grasp the cause of an abnormality and can effectively use the generated power of a DC power source composed of a solar battery panel or the like. It is to provide a conversion device.

  The power conversion device of the present invention boosts the voltage of the DC power generated by the solar cell panel, further converts the boosted DC voltage into an AC voltage, and electrically connects the solar cell panel to the load system and the commercial power system. A power conversion device connected to perform interconnection operation, wherein the power conversion device includes a voltage detection unit that detects a voltage of the commercial power system and a memory unit that stores data of the detected voltage. The memory unit stores the voltage data immediately before stopping when the abnormality operation is detected and the interconnection operation is stopped and the voltage data after a predetermined time after the interconnection operation is stopped. To do.

  According to the power conversion device of the present invention, the voltage of the DC power generated by the solar cell panel is boosted, and the boosted DC voltage is converted into an AC voltage, and the solar cell panel is electrically connected to the load system and the commercial power system. A power conversion device that performs interconnection operation by connecting to the power supply, the power conversion device including a voltage detection unit that detects a voltage of the commercial power system and a memory unit that stores data of the detected voltage The memory unit is configured to store the voltage data immediately before stopping when the abnormality operation is detected and the interconnection operation is stopped and the voltage data after a predetermined time after the interconnection operation is stopped. As a result, the state of the commercial power system at the time of occurrence of the abnormal condition can be grasped, the cause of the equipment stoppage can be confirmed, and whether the equipment stoppage is due to an external influence It is possible to provide a power conversion apparatus becomes possible to easily perform.

  For this reason, it is possible to provide a power conversion device that facilitates the recovery of the device and can efficiently and effectively use the power generated by the solar cell panel.

  Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings schematically showing the case of a solar power generation apparatus using a solar battery panel as a DC power source.

  FIG. 1 is a schematic configuration diagram of an example showing an embodiment of a power conversion device according to the present invention.

  As shown in FIG. 1, a power conversion device 1 includes a booster circuit 3 that boosts the voltage of a DC power source 2 that is a solar cell panel, and an inverter that converts the DC power converted by the booster circuit 3 into AC power. To record the circuit 4, the control circuit 15 that controls the booster circuit 3 and the inverter circuit 4, the voltage detection unit 16 that detects the voltage of the commercial power system 12, and the setting values and abnormal states that are necessary for the control. The memory unit 18 and the like.

  The step-up circuit 3 forms a chopper circuit by the reactor 5, the semiconductor switch element 6, the diode 7, and the smoothing capacitor 8, and thereby, voltage conversion of the DC voltage output from the DC power source 2 comprising a solar cell panel is performed. Is called.

  The inverter circuit 4 includes a bridge circuit 10 composed of a plurality of semiconductor switch elements and a filter circuit 11 composed of a reactor and a capacitor, and converts the DC power output from the booster circuit 3 into a sine wave commercial AC waveform. The AC power output from the inverter circuit 4 is connected to the commercial power system 12 and the load 13, and power is supplied to the load 13 and / or sold to the commercial power system 12.

  Next, operation | movement of the power converter device of this invention is demonstrated. DC power obtained from a DC power source 2 made of a solar cell panel is input to the power converter 1. In the booster circuit 3, the semiconductor switch element 6 is on / off controlled at high speed by the output control means 9, energy is accumulated in the reactor 5 when the semiconductor switch 6 is on, and the energy is stored when the semiconductor switch 6 is off. By passing through the diode 7 and being output to the smoothing capacitor 8 part, it is possible to boost the voltage to a DC voltage different from the DC voltage input from the DC power source 2 formed of a solar cell panel.

  In order to be able to adjust the output voltage corresponding to the change in the input voltage of the booster circuit 6, the semiconductor switch element 6 is controlled by a PWM method (pulse width modulation) that controls the duty of the pulse according to the converted voltage. Is desirable. Further, it is desirable that the converted DC voltage is a voltage value at which the inverter circuit 4 operates efficiently.

  The DC power input to the inverter circuit 4 is subjected to PWM (pulse width modulation) control by the high-speed switching operation of the bridge circuit 10 and is passed through the filter circuit 11 which is an LPF (low-pass filter) to thereby output a sinusoidal AC output. Is obtained. The output AC power is supplied to a load 13 that is an AC device such as a motor or lighting. If the amount of power generated by the DC power source 2 composed of a solar panel exceeds the load power, the surplus power is used as commercial power. The power is sold by causing the grid 12 to flow backward.

  Further, the control circuit 15 controls the booster circuit 3 and the inverter circuit 4 as described above so as to synchronize the output current with the voltage data of the commercial power system 12 obtained from the voltage detection unit 16, so that the grid interconnection operation is performed. In addition, when an abnormality occurs in the device main body or the commercial power system 12, it functions to stop the device.

  Here, in the control circuit 15, the voltage data of the voltage detection unit 16 acquired during the grid connection operation is temporarily stored, and when an abnormality is detected and the device is stopped, immediately before the device is stopped. The voltage data is operated to be stored in the memory unit 18. Further, the memory unit 18 is operated to store voltage data for a predetermined time after the device is stopped.

  As an example of a specific operation, the voltage detection unit performs sampling and averaging processing on the voltage instantaneous value detected from a resistor, a transformer, and the like, and temporarily stores the instantaneous value or the average value in the CPU of the control unit. When it is determined that the value is not within the predetermined specified range, the device is stopped and the instantaneous value and average value of the voltage stored immediately before are stored in the memory unit. Similarly, the instantaneous value and the average value of the voltage are acquired and stored in the memory during a predetermined time (several ms to several tens of seconds) after the device is stopped.

  FIG. 2 is a voltage waveform diagram showing an example of an embodiment of a power converter according to the present invention, and FIG. 3 is a voltage waveform diagram showing an example of an embodiment of a power converter according to the present invention.

  In the memory unit 18, both the voltage data of the commercial power system at the time (immediately before) when the device is stopped and the voltage data of the commercial power system after the device is stopped when the device is stopped are waveform-like. If the voltage data of the commercial power system after the equipment is stopped is a clean sine wave as shown in FIG. 2, the possibility of an error due to the influence of the disturbance is low or instantaneous If the waveform is distorted as shown in FIG. 3, it is highly likely that the error is caused by the surrounding environment and the distribution system that are not caused by the power converter. Can do.

  In other words, by storing the voltage data immediately before the equipment stopped, the voltage value and voltage waveform state of the commercial power system at the time of occurrence of the abnormal condition can be grasped, and the cause of the equipment shutdown can be confirmed from the contents. By storing the voltage data after stopping the equipment, it is possible to grasp the state of the commercial power system in a state that does not depend on the operation of the equipment (the state of the commercial power system itself that is not affected by the power converter) By comparing these two voltage waveforms and comparing each voltage waveform with the sine wave, it is possible to easily determine whether the stoppage of the equipment is due to the influence of disturbance. is there.

It is a schematic block diagram of an example which shows embodiment of the power converter device which concerns on this invention. It is a voltage waveform diagram which shows an example of embodiment of the power converter device which concerns on this invention. It is a voltage waveform diagram which shows an example of embodiment of the power converter device which concerns on this invention. It is a schematic block diagram which shows the form of the grid connection system in a prior art. It is a schematic block diagram of an example which shows the form of the power converter device in a prior art.

Explanation of symbols

1: Power conversion device 2: DC power source comprising a solar cell panel 3: Booster circuit 4: Inverter circuit 5: Reactor 6: Semiconductor switch element 7: Diode 8: Smoothing capacitor 9: Output control means 10: Bridge circuit 11: Filter circuit 12: Commercial power system 13: Load 15: Control circuit
16: Voltage detection unit 18: Memory unit 21: Power converter 23: Booster circuit 24: Inverter circuit 25: Control circuit 26: Voltage detection unit 27: Current detection unit 28: Memory unit

Claims (1)

The voltage of the DC power generated by the solar panel is boosted, the boosted DC voltage is converted into an AC voltage, and the solar panel is electrically connected to the load system and the commercial power system to perform interconnection operation. A power converter, wherein the power converter is provided with a voltage detector for detecting the voltage of the commercial power system and a memory for storing data of the detected voltage, and an abnormality is detected in the memory Then, the data of the voltage immediately before stopping when the interconnection operation is stopped and the data of the voltage after a predetermined time after stopping the interconnection operation are stored.

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