Inverter, power supply system and method of reducing leakage current in power supply system
First Claim
1. A non-insulated type inverter for converting DC power to AC power and outputting the AC power to a single-phase three-wire AC power system having a grounded neutral point, comprising:
- a converter circuit for boosting voltage of DC power that has entered from two terminals;
an inverter circuit for converting DC voltage, which has been boosted by said converter circuit, to alternating current;
a detector for detecting AC components of voltages to ground produced at respective ones of the two terminals; and
a controller for reducing the AC components of the DC voltage, which is input to said inverter circuit, based upon outputs of said detector.
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Accused Products
Abstract
In a power supply system for converting the output of a DC power supply having an earth capacitance to AC power, an input voltage from an input-voltage detector and an intermediate voltage from an intermediate-voltage detector are input to an input-ripple controller. The latter calculates the difference between ripple voltages of the two voltages. The input-ripple controller adjusts the size of a ripple command value, which indicates the ripple current that is to be input to a converter circuit, so as to null the difference between the ripple voltages. Furthermore, using a ripple reference waveform having a DC level, the input-ripple controller generates a ripple current waveform so as to null the average value of a full-wave rectified waveform synchronized to the output of an inverter circuit, and outputs the generated ripple current waveform to an output calculator. The output calculator adds the DC current command from the input-voltage controller and the ripple current waveform from the input ripple controller to thereby generate an output current waveform, which is output to a converter circuit driver.
149 Citations
27 Claims
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1. A non-insulated type inverter for converting DC power to AC power and outputting the AC power to a single-phase three-wire AC power system having a grounded neutral point, comprising:
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a converter circuit for boosting voltage of DC power that has entered from two terminals;
an inverter circuit for converting DC voltage, which has been boosted by said converter circuit, to alternating current;
a detector for detecting AC components of voltages to ground produced at respective ones of the two terminals; and
a controller for reducing the AC components of the DC voltage, which is input to said inverter circuit, based upon outputs of said detector. - View Dependent Claims (2, 3)
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4. A non-insulated type inverter for converting DC power to AC power and outputting the AC power to a single-phase three-wire AC power system having a grounded neutral point, comprising:
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a converter circuit for boosting voltage of entered DC power;
an inverter circuit for converting DC voltage, which has been boosted by said converter circuit, to alternating current;
an intermediate smoothing capacitor provided between said converter circuit and said inverter circuit;
a first detector for detecting an AC component of DC voltage that is input to said converter circuit;
a second detector for detecting an AC component of voltage at both ends of said intermediate smoothing capacitor; and
a controller for controlling the DC voltage input to said converter circuit in such a manner that the two AC components detected by said first and second detectors will be synchronized. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 13, 15, 16, 17, 19, 20, 21)
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12. A non-insulated type inverter for converting DC power to AC power and outputting the AC power to a single-phase three-wire AC power system having a grounded neutral point, comprising:
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a converter circuit for boosting voltage of DC power that has entered from two terminals;
an inverter circuit for converting DC voltage, which has been boosted by said converter circuit, to alternating current; and
an input-voltage controller for controller for changing the value of voltage, which is input to said converter circuit, in such a manner that AC components of the voltages to ground produced at the two terminals will take on phases that are the opposite of each other.
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14. A power supply system comprising:
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a DC power supply having an earth capacitance; and
a non-insulated type inverter for converting DC power to AC power and outputting the AC power to a single-phase three-wire AC power system having a grounded neutral point, including, a converter circuit for boosting voltage of entered DC power, an inverter circuit for converting DC voltage, which has been boosted by said converter circuit, to alternating current, an intermediate smoothing capacitor provided between said converter circuit and said inverter circuit, a first detector for detecting an AC component of DC voltage that is input to said converter circuit, a second detector for detecting an AC component of voltage at both ends of said intermediate smoothing capacitor, and a controller for controlling the DC voltage input to said converter circuit in such a manner that the two AC components detected by said first and second detectors will be synchronized.
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18. A power supply system comprising:
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a DC power supply having an earth capacitance; and
a non-insulated type inverter for converting DC power to AC power and outputting the AC power to a single-phase three-wire AC power system having a grounded neutral point, including, a converter circuit for boosting voltage of entered DC power, an inverter circuit for converting DC voltage, which has been boosted by said converter circuit, to alternating current, an intermediate smoothing capacitor provided between said converter circuit and said inverter circuit, a first detector for detecting an AC component of DC voltage that is input to said converter circuit, a second detector for detecting an AC component of voltage at both ends of said intermediate smoothing capacitor, and a controller for controlling the DC voltage input to said converter circuit in such a manner that the two AC components detected by said first and second detectors will be synchronized.
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22. A power supply system comprising:
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a DC power supply having an earth capacitance; and
a non-insulated type inverter for converting DC power to AC power and outputting the AC power to a single-phase three-wire AC power system having a grounded neutral point, including a converter circuit for boosting voltage of DC power that has entered from two terminals, an inverter circuit for converting DC voltage, which has been boosted by said converter circuit, to alternating current, and an input-voltage controller for controller for changing the value of voltage, which is input to said converter circuit, in such a manner that AC components of the voltages to ground produced at the two terminals will take on phases that are the opposite of each other. - View Dependent Claims (23, 24, 25)
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26. A method of reducing leakage current of a power supply system having a non-insulated type inverter which includes a converter circuit for boosting voltage of DC power that has entered from two terminals, and an inverter circuit for converting the DC voltage, which has been boosted by said converter circuit, to alternating current, said inverter converting DC powder to AC power and outputting the AC power to a singlephase, three-wire AC power system having a neutral point that is connected to ground, said method comprising the steps of:
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detecting AC components of voltages to ground produced at respective ones of the two terminals; and
reducing the AC components of the DC voltage, which is input to said inverter circuit, based upon results of detection.
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27. A method of reducing leakage current of a power supply system having a non-insulated type inverter which includes a converter circuit for boosting voltage of entered DC power, an inverter circuit for converting DC voltage, which has been boosted by said converter circuit, to alternating current, and an intermediate smoothing capacitor provided between said converter circuit and said inverter circuit, said inverter converting DC powder to AC power and outputting the AC power to a single-phase, three-wire AC power system having a neutral point that is connected to ground, said method comprising the steps of:
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detecting an AC component of DC voltage that is input to said converter circuit and an AC component of voltage at both ends of said intermediate smoothing capacitor; and
controlling the DC voltage input to said converter circuit in such a manner that the two AC components will be synchronized.
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Specification