Auxiliary power supply system for providing DC power on demand

An auxiliary power supply system for providing DC power to DC bus lines across which a storage battery is connected, comprising:

• (a) an internal combustion engine and means for responding to a control signal to start the engine;
• (b) an alternator coupled to the engine to be driven by it and having AC output terminals;
• (c) a rectifier connected to the output terminals of the alternator for rectifying the AC output of the alternator to a DC voltage adapted to be connected to the DC bus lines;
• (d) means for controlling the alternator when the engine is running to provide a controlled DC output voltage from the rectifier to the DC bus lines;
• and
• (e) control means, connected to the means for responding to a control signal to start the engine, for monitoring the time elapsed since the last turn-off of the engine and if the time elapsed exceeds a predetermined time interval providing a control signal to start the engine and controlling the alternator so that no power is delivered from the alternator to the DC bus lines, and controlling the engine to run for a selected period of time to allow the engine to adequately warm up and thereafter shutting off the engine.

A method of operating an auxiliary power supply system having an internal combustion engine connected to a generator system which provides Dc output power to DC bus lines across which a storage battery is connected, the storage battery providing backup power to a consuming device such as an uninterruptible power system or telecommunication system, comprising the steps of:

• (a) monitoring the voltage on the DC bus lines to determine when the voltage across the DC bus lines drops below a predetermined value indicating that power is being drawn from the battery by the consuming device;
• (b) when the voltage across the DC bus lines drops below the predetermined value, turning on the engine for a selected period of time to warm the engine up but without supplying power from the generator system to the DC bus lines during this warm-up period of time;
• (c) thereafter supplying power from the generator system to the DC bus lines to raise the voltage on the DC bus lines to a selected value which is less than the nominal open circuit voltage of the battery to thereby provide power to the consuming device primarily from the generator system and to partially charge the battery;
• (d) sensing when the consuming device is no longer drawing power from the generator system and then turning off the engine to stop supplying power from the generator system to the DC bus lines.

An auxiliary power supply system for providing DC power to DC bus lines across which a storage battery is connected, comprising:

• (a) an internal combustion engine and means for responding to a control signal to start the engine;
• (b) an alternator coupled to the engine to be driven by it and having AC output terminals;
• (c) a rectifier connected to the output terminals of the alternator for rectifying the AC output of the alternator to a DC voltage;
• (d) means for filtering the DC voltage from the rectifier to provide a filtered DC voltage to the DC bus lines;
• (e) means for controlling the alternator when the engine is running to provide a controlled Dc output voltage from the rectifier and means for filtering to the DC bus lines so that voltage across the DC bus lines is maintained at a selected voltage level;
• and
• (f) control means connected to monitor the voltage on the DC bus lines for providing a control signal to turn on the engine when the voltage across the DC bus lines drops below a predetermined value.

An auxiliary power supply system for providing DC power to DC bus lines across which a storage battery is connected, comprising:

• (a) an internal combustion engine and means for responding to a control signal to start the engine;
• (b) an alternator coupled to the engine to be driven by it and having AC output terminals;
• (c) a rectifier connected to the output terminals of the alternator for rectifying the AC output of the alternator to a DC voltage;
• (d) means for filtering the DC voltage from the rectifier to provide a filtered DC voltage to the DC bus lines;
• (e) means for controlling the alternator when the engine is running to provide a controlled DC output voltage from the rectifier and means for filtering to the DC bus lines;
• and
• (f) control means connected to monitor the voltage on the DC bus lines for providing a control signal to turn on the engine when the voltage across the DC bus lines drops below a predetermined value, wherein the control means senses the current drawn from the alternator on the DC bus lines, and wherein the control means turns off the engine when current being drawn from the alternator drops below a selected level.

An auxiliary power supply system for providing DC power to DC bus lines across which a storage battery is connected, comprising:

• (a) an internal combustion engine and means for responding to a control signal to start the engine;
• (b) an alternator coupled to the engine to be driven by it and having AC output terminals;
• (c) a rectifier connected to the output terminals of the alternator for rectifying the AC output of the alternator to a DC voltage which is adapted to be connected to the DC bus lines;
• (d) means for controlling the alternator when the engine is running to provide a controlled DC output voltage from the rectifier;
• and
• (e) control means connected to monitor the voltage on the DC bus lines for providing a control signal to turn on the engine when the voltage across the DC bus lines drops below a predetermined value, and wherein the control means includes means for monitoring at least one engine condition selected from the group consisting of engine temperature, oil pressure, and fuel level in a fuel tank which supplies fuel to the engine, wherein the control means stores the values of the sensed parameters in a memory and provides the values in the memory available for interrogation by an operator.

An auxiliary power supply system for providing DC power to DC bus lines across which a storage battery is connected, comprising:

• (a) an internal combustion engine and means for responding to a control signal to start the engine;
• (b) an alternator coupled to the engine to be driven by it and having AC output terminals;
• (c) a rectifier connected to the output terminals of the alternator for rectifying the AC output of the alternator to a DC voltage;
• (d) means for filtering the DC voltage from the rectifier to provide a filtered DC voltage to the DC bus lines;
• (e) means for controlling the alternator when the engine is running to provide a controlled DC output voltage from the rectifier and the means for filtering to the DC bus lines;
• and
• (f) control means connected to monitor the voltage on the DC bus lines for providing a control signal to turn on the engine when the voltage across the DC bus lines drops below a predetermined value, and wherein the control means includes means for monitoring the filtered DC voltage output of the rectifier and the means for filtering while the engine is running and for providing a warning signal to an operator if the output voltage is above or below predetermined limits.

An auxiliary power supply system for providing DC power to DC bus lines across which a storage battery is connected, comprising:

• (a) an internal combustion engine, and means for responding to a control signal to start the engine including a cranking battery and a starter motor to which the output of the cranking battery is supplied during starting;
• (b) an alternator coupled to the engine to be driven by it and having AC output terminals;
• (c) a rectifier connected to the output terminals of the alternator for rectifying the AC output of the alternator to a DC voltage which is adapted to be connected to the DC bus lines;
• (d) means for controlling the alternator when the engine is running to provide a controlled DC output voltage from the rectifier to the DC bus lines;
• and
• (e) control means connected to monitor the voltage on the DC bus lines for providing a control signal to turn on the engine when the voltage across the DC bus lines drops below a predetermined value, the control means including means for monitoring the voltage of the cranking battery, and wherein the control means provides a warning if the cranking battery voltage drops below a predetermined level and starts the engine for a predetermined period of time if the cranking battery voltage drops below a selected level, and wherein the system further includes a power supply means driven by the engine for providing charging current to the cranking battery during running of the engine to charge the cranking battery.

An auxiliary power supply system for providing DC power to DC bus lines across which a storage battery is connected, comprising:

• (a) an internal combustion engine and means for responding to a control signal to start the engine;
• (b) a polyphase alternator coupled to the engine to be driven by it and having polyphase AC output terminals;
• (c) a rectifier connected to the output terminals of the alternator for rectifying the polyphase AC output of the alternator to a DC voltage;
• (d) a filter connected to the rectifier to filter the power from the rectifier to provide a smooth DC output voltage to the DC bus lines;
• (e) means for controlling the alternator when the engine is running to provide a controlled DC output voltage from the rectifier through the filter to the DC bus lines;
• and
• (f) control means connected to monitor the voltage on the DC bus lines for providing a control signal to turn on the engine when the voltage across the DC bus lines drops below a predetermined value.