Control circuit, power conditioner including the control circuit, and photovoltaic system

Abstract

This invention provides a control circuit, a power conditioner including the control circuit, and a photovoltaic system, which can enable a power conditioner of a photovoltaic system to operate at higher accuracy. A chopper circuit (5), a capacitor (18) connected in parallel to the chopper circuit, and a control circuit (9) for controlling ON / OFF of switch elements (10, 11) in the chopper circuit to control charging and discharging of the capacitor are arranged, where the control circuit (9) includes a measurement control section (9a) for measuring an inter-end voltage of the capacitor (18) and a control circuit section (9b) for performing a predetermined control operation from a measurement output of the measurement circuit section (9a); the measurement circuit section (9a) including a differential amplifier circuit (9a2) for differentially amplifying the inter-end voltage of the capacitor (18), and the circuit control section (9b) calibrating an in-phase component in the output of the differential amplifier circuit (9a2) as an in-phase error and performing the control from the calibrated output from the differential amplifier circuit (9a2).

Description

technical field [0001] The invention relates to a control circuit, a power conditioner including the control circuit and a solar power generation system. Background technique [0002] Generally, the solar power generation system converts the DC power from the solar battery into the AC power of the commercial frequency connected to the system through the power conditioner, and provides the converted AC power to the household load connected to the commercial power system. On the one hand, when the AC power exceeds the power consumption of the load in the home, it is possible to reverse the surplus power to the system side. Among such power conditioners, non-isolated types with high power conversion efficiency are often used. (For example, refer to Patent Document 1). [0003] Figure 14 A configuration example of a photovoltaic power generation system including a non-isolated power conditioner is shown. The power conditioner 100 is connected to the commercial power supply 2...

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Problems solved by technology

[0010] However, when the above-mentioned two input components to the above-mentioned differential amplifier circuit include an in-phase component (for this, refer to the detailed description in the embodiment), the in-phase component appears as an error component in the output of the differential amplifier circuit. In the control circuit, this error component also appears in the A / D converted value of the output of the differential amplifier circuit, that is, the digital measurement signal. Since the on / off control of the switching element is performed based on this error component, the The high-precision operation of the power conditioner affects

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