UPS with input commutation between AC and DC sources of power
First Claim
1. An uninterruptible power supply, said power supply comprising:
- AC input terminal means for receiving a first AC voltage from an AC power source;
DC input terminal means for receiving a first DC voltage from a DC power source;
AC output terminal means for connecting to a load;
converter means for converting said first AC voltage to a second DC voltage across electrical charge storage means coupled to said converter means, said second DC voltage being larger than the maximum peak voltage of said first AC voltage and said first DC voltage;
switching means coupled to said AC power source and said DC power source for selectively connecting said AC power source or said DC power source to said converter means;
inverter means coupled to said electrical charge storage means for receiving said second DC voltage and inverting said second DC voltage to a second AC voltage, said second AC voltage being coupled to said AC output terminal means; and
control means coupled to said switching means for controlling the operation of said switching means, said control means operating said switching means to connect said AC power source to said converter means only when said first AC voltage is within a predetermined range and operating to connect said DC power source to said converter means when said first AC voltage is outside of said range.
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Accused Products
Abstract
An uninterruptible power supply is disclosed which is cheaper and more adaptable to various utility service inputs than presently available power supplies. A storage capacitor is placed between a boost AC/DC converter at the input and a DC/AC inverter at the output. A storage battery for maintaining constant voltage should the utility service power be interrupted is placed at the input, before the boost converter. Thus, a small battery is required because the boost converter is capable of boosting the battery'"'"'s voltage to the voltage contained on the storage capacitor. A bidirectional semiconductor switch is provided in the boost converter to allow current to flow in both directions between its switch terminals when a AC input is applied. Appropriate control circuitry is provided which monitors the voltage at specific points throughout the circuit and controls operation of the bidirectional switch. Additionally, the control circuitry controls operation of a relay to switch power input between the utility service input and the storage battery depending in part upon the state of the utility service input voltage.
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Citations
10 Claims
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1. An uninterruptible power supply, said power supply comprising:
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AC input terminal means for receiving a first AC voltage from an AC power source; DC input terminal means for receiving a first DC voltage from a DC power source; AC output terminal means for connecting to a load; converter means for converting said first AC voltage to a second DC voltage across electrical charge storage means coupled to said converter means, said second DC voltage being larger than the maximum peak voltage of said first AC voltage and said first DC voltage; switching means coupled to said AC power source and said DC power source for selectively connecting said AC power source or said DC power source to said converter means; inverter means coupled to said electrical charge storage means for receiving said second DC voltage and inverting said second DC voltage to a second AC voltage, said second AC voltage being coupled to said AC output terminal means; and control means coupled to said switching means for controlling the operation of said switching means, said control means operating said switching means to connect said AC power source to said converter means only when said first AC voltage is within a predetermined range and operating to connect said DC power source to said converter means when said first AC voltage is outside of said range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification