METHOD FOR DISTRIBUTED POWER MANAGEMENT
Alon Ferentz and Noam Tziony
Various
methods of power management are known, including the method taught in U.S.
Patent S/N 7,400,062 issued July 15, 2008 to Pincu et al, in which power is
allocated to a plurality of power managed modules by a management module, and
the power managed modules are operative to control module operation so that
power is drawn with the allocated budget.
The requirement for a management module increases cost and presents a
single point of failure.
Computer
rooms are rapidly evolving to a point where the demand for power exceeds the
power being supplied. Particularly, the
AC mains power supply to the computer room is limited to a certain amount of
power, however with increased servers, and the centralized power requirements
of Power over Ethernet, demand, in not controlled may exceed the supply of AC
mains power.
Looking at
Fig. 1, we see an example of a plurality of power managed modules (1 to N
modules), each receiving power from a shared power source. Fig. 1 particularly shows the shared power
source being a power bank of a plurality of DC/DC power sources, however the concepts
described herein are equally applicable to an AC mains connection. Each of the plurality of power managed modules
is illustrated as a PoE sourcing equipment, in which a plurality of powered
devices (PD) are controllably connected to the shared power source. Power draw of each of the PDs is monitored by
a respective power meter, which may be implemented as a current sensor and a
voltage sensor. The power meters provide
inputs to the control unit of the respective power managed module. Each of the electronically controlled
switches which connect the respective PDs to the shared power source are under
control of the control unit. The control
units of the power managed modules are in communication with each other.
Fig. 2
illustrates a first algorithm in which power is shared between the control
units of the respective power managed modules without requiring a master
unit. In particular, an indication of
total available power is input, which in one embodiment is responsive to the
existence of an active power good (PG) signal from each of the power sources of
the shared power source. The control
units of the power managed modules initially self allocate power between
themselves, in one embodiment on an equal basis, and in another embodiment
responsive to the number of ports supported by each of them. Any control unit requiring additional power
requests the additional power from all other control units, optionally in units
of a predetermined quantum. Any control
unit exhibiting unused allocated power transmits the allocation in response to
the control unit requiring additional power.
The transmittal of the allocation is accomplished by data communication,
allowing the requesting control unit to increase the power allocation...
