POWER CONVERTING APPARATUS
First Claim
1. A power converter which converts AC power to DC power or vice versa, the power converter comprising:
- Magnetic Energy Recovery Switch comprising a bridge circuit including four reverse conductive type semiconductor switches and a magnetic energy accumulating capacitor C which accumulates magnetic energy possessed by a current at the time of current cutoff and which is connected between DC terminals DC(P), DC(N) of the bridge circuit, and whereinthe power converter employs a circuit configuration in which an AC power source is connected between AC terminals AC, AC of the bridge circuit through a inductor Lac, and a DC power source or a load is connected between the DC terminals DC(P), DC(N) through a smoothing inductor Ldc, and whereinthe power converter further comprises;
a gate control device which performs on/off control on the reverse conductive type semiconductor switches by supplying a control signal to a gate of each reverse conductive type semiconductor switch, the gate control device performing controlling in such a way that a pair of the reverse conductive type semiconductor switches on a diagonal line of the bridge is turned on, while at the same time, another pair of the reverse conductive type semiconductor switches is turned off, the gate control device also allowing a pair of the reverse conductive type semiconductor switches selected by a direction of a current from the AC power source to perform high speed on/off operation;
means for generating a boosted pulse voltage between the DC terminals DC(P), DC(N); and
means for allowing the boosted pulse voltage to flow in the DC power source, a secondary battery (battery) or the AC load through the smoothing inductor Ldc in order to smooth and convert the boosted pulse voltage to a DC voltage, and whereinthe power converter is connected to a secondary battery (battery) charging device in series or in parallel, or a series connection and a parallel connection is interchanged by an opening/closing switch, the secondary battery charging device controls charging conditions, such as a temperature of the secondary battery (battery) and a charging amount of the secondary battery, in a long term, shifts a power factor of an input current from a lagging power factor to a leading power factor in a short term, and adjusts a current power factor together with a lagging power factor of another power system to reduce the current, thereby reducing Joule loss and compensating voltage variation, overvoltage, and undervoltage at a power receiving point.
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Accused Products
Abstract
A power converter stabilizes a voltage by controlling leading of an AC current and performs maximum charging within contracted power reception amount when connected to a weak power system. The power converter comprises Magnetic Energy Recovery Switch comprising a bridge circuit including at least two reverse conductive type semiconductor switches and a magnetic energy accumulating capacitor with a small capacity connected between DC terminals of the bridge circuit. The power converter uses the Magnetic Energy Recovery Switch to perform power conversion from AC to DC or vise versa. Plurality of secondary battery charging devices each comprising the power converter have a DC part connected to a common DC bus bar, so that power is accommodated among the secondary battery charging devices.
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Citations
18 Claims
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1. A power converter which converts AC power to DC power or vice versa, the power converter comprising:
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Magnetic Energy Recovery Switch comprising a bridge circuit including four reverse conductive type semiconductor switches and a magnetic energy accumulating capacitor C which accumulates magnetic energy possessed by a current at the time of current cutoff and which is connected between DC terminals DC(P), DC(N) of the bridge circuit, and wherein the power converter employs a circuit configuration in which an AC power source is connected between AC terminals AC, AC of the bridge circuit through a inductor Lac, and a DC power source or a load is connected between the DC terminals DC(P), DC(N) through a smoothing inductor Ldc, and wherein the power converter further comprises; a gate control device which performs on/off control on the reverse conductive type semiconductor switches by supplying a control signal to a gate of each reverse conductive type semiconductor switch, the gate control device performing controlling in such a way that a pair of the reverse conductive type semiconductor switches on a diagonal line of the bridge is turned on, while at the same time, another pair of the reverse conductive type semiconductor switches is turned off, the gate control device also allowing a pair of the reverse conductive type semiconductor switches selected by a direction of a current from the AC power source to perform high speed on/off operation; means for generating a boosted pulse voltage between the DC terminals DC(P), DC(N); and means for allowing the boosted pulse voltage to flow in the DC power source, a secondary battery (battery) or the AC load through the smoothing inductor Ldc in order to smooth and convert the boosted pulse voltage to a DC voltage, and wherein the power converter is connected to a secondary battery (battery) charging device in series or in parallel, or a series connection and a parallel connection is interchanged by an opening/closing switch, the secondary battery charging device controls charging conditions, such as a temperature of the secondary battery (battery) and a charging amount of the secondary battery, in a long term, shifts a power factor of an input current from a lagging power factor to a leading power factor in a short term, and adjusts a current power factor together with a lagging power factor of another power system to reduce the current, thereby reducing Joule loss and compensating voltage variation, overvoltage, and undervoltage at a power receiving point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 16, 17, 18)
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9. A power converter comprising Magnetic Energy Recovery Switch, the Magnetic Energy Recovery Switch including:
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a bridge circuit comprising four reverse conductive type semiconductor switches; a magnetic energy accumulating capacitor C connected between DC terminals of the bridge circuit, and accumulating magnetic energy possessed by a current at the time of current cutoff; and a gate control device which applies a control signal to a gate of each reverse conductive type semiconductor switch, and which performs controlling in such a way that a pair of the reverse conductive type semiconductor switches on a diagonal line of the bridge circuit is turned on, while at the same time, another pair of the reverse conductive type semiconductor switches is turned off, and wherein; an AC terminal of the bridge circuit is connected to an AC or DC input power source through a inductor Lac; a DC terminal of the bridge circuit is connected to a DC output power source through a smoothing inductor Ldc; the gate control device causes a pair of the reverse conductive type semiconductor switches selected based on a direction of a current from the input power source to perform on/off operation at a high speed, and causes another pair of the reverse conductive type semiconductor switches to turn off, thereby generating a boosted pulse voltage between DC terminals of the bridge circuit; the smoothing inductor Ldc smooths the boosted pulse voltage to convert the boosted pulse voltage into a DC voltage; and the high speed on/off operation synchronizes a high speed on/off control frequency lower than a resonance frequency of the bridge circuit set based on a capacity of the magnetic energy accumulating capacitor C and an inductance (Lac) of the inductor Lac, and a flow of a power between the input power source and the DC output power source is controlled by changing the high speed on/off control frequency and/or an on/off time ratio. - View Dependent Claims (10, 11)
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12. A power converter comprising:
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first Magnetic Energy Recovery Switch including a first bridge circuit consisting of four first reverse conductive type semiconductor switches, a first magnetic energy accumulating capacitor C connected between the DC terminals DC (P), DC (N) of the bridge circuit for accumulating the magnetic energy held by the current at the time of current cutoff, and a first gate control device supplying control signals to the gates of said first reverse conductive type semiconductor switches for turning on/off said first reverse conductive type semiconductor switches; and second Magnetic Energy Recovery Switch including a second bridge circuit consisting of four second reverse conductive type semiconductor switches, a second magnetic energy accumulating capacitor C connected between the DC terminals DC (P), DC (N) of the bridge circuit for accumulating the magnetic energy held by the current at the time of current cutoff, and a second gate control device supplying control signals to the gates of said second reverse conductive type semiconductor switches for turning on/off said second reverse conductive type semiconductor switches, wherein the AC terminals AC, AC of said first bridge circuit can be connected to an AC power source via a first inductor Lac, the DC terminals DC (P), DC (N) of said first bridge circuit are connected to a DC bus bar via a first smoothing inductor Ldc, either the AC terminals AC, AC of said second bridge circuit or the DC terminals DC (P), DC (N) of said second bridge circuit are connected to said DC bus bar via a second inductor Lac or via a second smoothing inductor Ldc, and the other terminals can be connected to a secondary battery, said first and second gate control devices allow one of said pairs of reverse conductive type semiconductor switches that is selected according to the current direction of the input power source to perform high speed on/off operation and turn off the other pair of reverse conductive type semiconductor switches so as to generate a boosted pulse voltage at said DC terminals of the corresponding one of said bridge circuits, said smoothing inductor Ldc smoothes and converts said boosted pulse voltage to a DC voltage, in said high speed on/off operation of said first Magnetic Energy Recovery Switch, said pairs of reverse conductive type semiconductor switches, which are selected according to the current direction of said input power source and perform the high speed on/off operation in sync with a first high speed on/off control frequency lower than the resonant frequency of said first bridge circuit and determined by the capacitance (C) of said first magnetic energy accumulating capacitor C and the inductance (Lac) of said first inductor Lac, are alternated in sync with the frequency of said AC voltage, and said first high speed on/off control frequency and/or the on/off time ratio is changed to control the power flow between said AC power source and DC bus bar, and in said high speed on/off operation of said second energy recovery switch, only one of said pairs of reverse conductive type semiconductor switches is selected according to the current direction of said input power source and performs the high speed on/off operation in sync with a second high speed on/off control frequency lower than the resonant frequency of said second bridge circuit and determined by the capacitance (C) of said second magnetic energy accumulating capacitor C and the inductance (Lac) of said second inductor Lac, and the other pair is normally turned off, and said second high speed on/off control frequency and/or the on/off time ratio is changed to control the power flow between said DC bus bar and secondary battery. - View Dependent Claims (13, 14, 15)
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Specification