Reduced capacitance AC/DC/AC power converter
First Claim
1. An AC/DC/AC power converter, comprising:
- A rectifier having diodes, anode of one said diode connected to cathode of another said diode to form a phase leg, the middle node of said diode leg serves to accepts one input power line, the free cathode end of all said diode legs are tied as a positive terminal and free anodes of all legs are similarly tied together to serve as the negative terminal;
An inverter having switching semiconductors, with a free-wheeling diode connected across each said switching semiconductor to form a be-directional current carrying switch-diode module, two said modules to form a leg, the middle node of said leg serves as an output terminal, free nodes of all legs with diode cathode to tie together to accept DC positive bus, free nodes of all legs with diode anode to tie together as negative terminal;
A DC link section with an inductor, a capacitor and a precharge means in series, said capacitor is constructed with film or ceramic materials, said capacitor terminals serve as DC output for said inverter;
A control means supplying signals engaging or disengaging said capacitor to input and output of said converter. Whereby said capacitance in said DC link section is reduced and capacitor construction is simplified for compactness, endurance and reliability of said converter. The over-voltage transient is protected by fast reaction of said control means.
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Accused Products
Abstract
An AC/DC/AC power converter is constructed without using any electrolytic capacitor, such that it is more compact, durable and reliable. This converter only required a small capacitance for its DC link and this capacitor can be easily obtainable with other types of capacitors such as film or ceramic type. The system further includes means to disconnect both input and output to this DC bus capacitor. A controller capable of fast monitoring the DC bus voltage is also able of quickly disconnecting the capacitor out of either input or output energy path to prevent the capacitor from being charged to over-voltage. The controller also possesses capability of re-connecting the disrupted energy path once the DC bus voltage returns to normal.
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Citations
14 Claims
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1. An AC/DC/AC power converter, comprising:
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A rectifier having diodes, anode of one said diode connected to cathode of another said diode to form a phase leg, the middle node of said diode leg serves to accepts one input power line, the free cathode end of all said diode legs are tied as a positive terminal and free anodes of all legs are similarly tied together to serve as the negative terminal;
An inverter having switching semiconductors, with a free-wheeling diode connected across each said switching semiconductor to form a be-directional current carrying switch-diode module, two said modules to form a leg, the middle node of said leg serves as an output terminal, free nodes of all legs with diode cathode to tie together to accept DC positive bus, free nodes of all legs with diode anode to tie together as negative terminal;
A DC link section with an inductor, a capacitor and a precharge means in series, said capacitor is constructed with film or ceramic materials, said capacitor terminals serve as DC output for said inverter;
A control means supplying signals engaging or disengaging said capacitor to input and output of said converter. Whereby said capacitance in said DC link section is reduced and capacitor construction is simplified for compactness, endurance and reliability of said converter. The over-voltage transient is protected by fast reaction of said control means. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An AC/DC/AC power converter, comprising:
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An AC section connecting an input power source to a rectifier;
A rectifier having diodes, anode of one said diode connected to cathode of another said diode to form a phase leg, the middle node of said diode leg serves to accepts one input power line, the free cathode end of all said diode legs are tied as a positive terminal and free anodes of all legs are similarly tied together to serve as the negative terminal;
An inverter having switching semiconductors, with a free-wheeling diode connected across each said switching semiconductor to form a be-directional current carrying switch-diode module, two said modules to form a leg, the middle node of said leg serves as an output terminal, free nodes of all legs with diode cathode to tie together to accept DC positive bus, free nodes of all legs with diode anode to tie together as negative terminal;
A DC link section with at least a capacitor, said capacitor is constructed with film or ceramic materials;
A control means supplying signals engaging or disengaging said capacitor to input and output of said converter. Whereby said capacitance in said DC link section is reduced and capacitor construction is simplified for compactness, endurance and reliability of said converter. The over-voltage transient is protected by fast reaction and regulation of said control means. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification