System and method for a redundant power solution

A redundant power solution system, including at least a first and second input module, each configured for receiving input power, an output converter, wherein a first output line from the first input module and a second output line from the second module both feed into the output converter, and a control mechanism associated with the first and second input modules, wherein the control mechanism monitors the input power received by the first and second input modules and dynamically selects at least one of the first and second input modules to feed power into the output converter.

BACKGROUND OF THE INVENTION

The present invention relates generally to AC-DC converters, and more specifically to AC-DC converters used in computer servers and which provide redundancy.

A power supply refers to a source of electrical power wherein electrical energy is supplied to an output load or a group of output loads. Power converters provide for conversion of one form of electrical power to another desired form and voltage. One common example is an AC-DC converter, which converts an AC line voltage to a well-regulated lower-voltage DC current commonly used for electronic devices. Low voltage, low power DC power supply units are commonly integrated with the devices they supply power, such as computers and household electronics.

Power supplies also commonly employ some technique of redundancy to minimize the chances of a system or component losing power. Redundant power supplies are essentially power systems that include two or more units within it, each of which is capable of powering the entire system by itself. Therefore, if for some reason there is a failure in one of the units, the other one can seamlessly take over to prevent the loss of power to the system. In some configurations, one can even replace the damaged unit without powering down the machine. This is commonly referred to as hot swapping, and is commonly used with computer servers or other machines that are used by a large number of people.

Traditional AC-DC converters also use an input rectifier to convert AC power to DC power and also to employ power factor correction (i.e., shape input current to match voltage to provide an improved power factor). Further, that rectified voltage is then converted to a lower voltage output, which actually runs the server.

DETAILED DESCRIPTION

The present invention provides a power solution that provides benefits over the traditional two-converter redundant AC to DC power supply described above. In one embodiment of the present invention, the two-converter power supply is replaced with redundant single converter AC to DC power factor correcting power supplies (i.e., an input module) which powers a common output converter. In some embodiments, the redundant input modules are run exclusive of one another to allow use of non-isolated converter topologies.

Referring now toFIG. 1, an example embodiment redundant power solution system10is shown. Included in the power solution system10is a first input module12having input lines14,16, and output line18. Similarly, a second input module20has input lines22,24, and output line26. The two input modules12,20are each configured for receiving input power over the input lines14,16,22,24. Notably, the power solution system is not limited to two input modules, but instead can include two or more input modules. Further, throughout this application, any reference to “a,” “an,” or “the” should be interpreted to mean “at least one,” unless otherwise specified.

Further included in the power solution system is an output converter28. The output lines18,26of the input modules12,20are merged and feed into the output converter28. A control mechanism30associated with the input modules12,20(preferably through additional output lines32,34from the input modules12,20) monitors the input power received by the input modules and dynamically selects at least one of the input modules to feed power into the output converter28. Notably, in another example embodiment, the input modules12,20are controlled using switches30aon each output line18,26(SeeFIG. 2).

While multiple output converters28can be used, only a single output converter is used in the described embodiment. The output converter28can also be composed of either parallel redundant or non-redundant converters. Redundant converters employ such known redundancy techniques that ensure system availability in the event of component failure. The level of resilience is referred to as active/passive or standby as backup components do not actively participate within the system during normal operation. The extent of the backup (i.e., the number of backup components provided) can be altered depending on the system requirements. As such, it is common to employ N+1 or N+N redundancy techniques. N-redundancy (i.e., non-redundancy) means the system has enough converters to provide the required power. For example, if the system has up to a 600 watt load and a single 600 watt converter, the system employs N-redundancy. Indeed, the system can run fine unless the single converter fails. In that case, the system would have insufficient power and would be unable to operate. N+1 redundancy allows for failure of one converter while still allowing the system to run. For example, if the system having up to a 600 watt load has two 600 watt converters (or three 300 watt converters), even with one of the converters failing, the system would still have sufficient power and could continue operation. If N+1 operation were employed in the present invention, the described system would include multiple input and output modules. Notably, redundancy can exceed N+1 (i.e., N+N), whereby the system allows for multiple power supply (including input power) failures while still providing sufficient power to the system.

The output converter28can also be either an isolated or a non-isolated converter. Isolated converters refer to converters that have an electrical barrier between the input and output of the converter, where as non-isolated converters have no barriers. As such, isolation describes the electrical separation between the input and output of a converter. An isolated converter uses a transformer to eliminate the DC path between its input and output. Non-isolated DC-DC converter designs usually employ isolated converters specifically intended for that purpose. Finally, an energy storage component36is positioned to operationally connect to lines18,26(where they merge to form a single lead38to the output converter28).

Operation of an embodiment of the present invention will now be described with respect toFIG. 3, which depicts a circuit diagram showing an example operation within the control circuit30. Included in the circuit are two silicon controlled rectifiers (SCRs)40, which provide for forward biasing as associated device. Notably, SCRs will not conduct until a current is injected into it. However, as soon as a current is injected into the SCR40, the SCR will continue to conduct current until the current traversing through it reduces to zero.

Traditional AC sources42provide zero crossings twice per cycle. For example, in a 60 hertz signal, there are 120 crossings per second with each zero crossing causing the device to turn off. As such, with a pair of SCRs40as shown inFIG. 3, they can be operated in conjunction such that one SCR gets turned on and is let run. Then, when the first SCR turns off, the other SCR40turns on. This process is then repeated providing alternating operation of the two SCRs40. As described in greater detail below, a controller provides for turning on an SCR and letting the converter operating for the entire half cycle and then turning on the next SCR, thereby cycling through the parallel converters. Failure to utilize this technique could potentially lead to current entering from a diode46and leaving through an SCR40(in a parallel module). Notably, this issue does not exist for a single input module, but instead only for parallel input modules. Yet another technique provides for monitoring the output converter28to determine if a fault occurs. If a fault does occur, another one of the input modules12,20is selected to provide power to the output converter.

Further included in the circuit is a gate44. In the example embodiment, the gate44is implemented using a MOSFET. When a positive voltage is applied to a bottom piece of the gate, the gate allows electrons to flow through. As such, when the gate is on, energy flows such that the current enters the MOSFET through the drain and exists through the source. Also, when the MOSFET is off, the current will still move through SCRs40. However, the current will move though the diode48and come back through the capacitor50or the load connected to points36and38. As described above, the circuit is associated with a controller30(e.g., micro or analog) to control operation of the circuit (FIG. 1). The controller30is configured such that it monitors input power of the input modules12,20and dynamically controls which input module is able to provide power at any given time. As noted above, this control can be established for example, by using SCRs40. As such, the controller30dynamically manages the SCRs in each input module12,20to control which input power source provides current, as well as where the current returns from. The controller30is also configured to dynamically adjust load sharing between two input modules. Such sharing can therefore be done on-the-fly to assist with load balancing across multiple servers and power feeds. Further in the example embodiment shown, control logic and energy storage36is located at the common output38and is sized accordingly such that it provides the necessary holdup energy for the common output38. Notably, the embodiment described above can be extended to N modules running in parallel to provide more efficient conversion of AC to DC power.

With the embodiment described above, the need for two output conversion stages for redundant power supplies in order to establish the required availability for various uptime standards (as required by the prior art) is eliminated. In the present embodiment, the majority of conversions are performed at the input conversion side (rather than the output conversion side as with the prior art). Further, using a common output conversion stage improves efficiency, reduces costs, and saves space. Notably, real estate within a server which is a valuable resource.

In addition, servers typically have removable power supplies (i.e., in which the entire power supply is removed and replaced). In the described embodiment, the input converters are easily swappable on their own, while the output converter is essentially integrated into the server. Notably, the output converter could be removed, but the server would likely need to be taken offline. However, in most instances, it should only be the input converter12,20which needs to be swapped. Notably, while the example embodiments have been described as being installed within a server, the present invention is not so limited and could be installed and/or associated with any device or component needing a power source.

While several particular embodiments of a method and system for removing a tunnel between portal points have been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects and as set forth in the following claims.