Electric power conversion systems – Current conversion – With condition responsive means to control the output...
Reexamination Certificate
2001-01-24
2001-12-11
Berhane, Adolf Deneke (Department: 2838)
Electric power conversion systems
Current conversion
With condition responsive means to control the output...
C307S064000
Reexamination Certificate
active
06330174
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an uninterruptible power supply, which is operating in a current control mode when the backup power is activated to supply power, so as to enhance the efficiency and increase the lifetime of the battery.
2. Description of Related Art
FIG. 4
shows a conventional uninterruptible power supply, which includes a voltage boost unit
80
, an average current mode controller
81
(ACMA), a backup power supply unit
82
and a detection/control unit
83
. The voltage boost unit
80
is arranged between power input ends L and N and the inverter (not shown), and is composed of a voltage-boost coil L, a bridge rectifier BD, two diodes D
1
and D
2
, and two capacitors C
1
and C
2
, etc, wherein the bridge rectifier is controlled by an electronic switch Q to be turned on or turned off.
The average current mode controller
81
is provided to detect and control the output voltage of the voltage boost unit
80
. The average current mode controller
81
detects the current value of the input choke L from a current transformer CT of the voltage boost unit
80
, so as to control the power supply operation of the average current mode controller
81
via the electronic switch Q.
The backup power supply unit
82
includes a DC/DC converter
821
, a battery set
822
connected to the input of the DC/DC converter
821
, and a voltage mode controller (VMC)
823
for controlling the DC/DC converter
821
. The DC/DC converter
821
is provided to boost the output voltage of the battery set
822
. The output ends of the DC/DC converter
821
are connected to the output ends +BUS and −BUS of the voltage boost unit
80
in parallel for supplying backup power. The voltage mode controller
823
is provided to detect the output voltage of the DC/DC converter
821
, so as to provide a feedback signal to the DC/DC converter
821
thereby controlling the output voltage.
The detection/control unit
83
is typically composed of a microprocessor or analog and digital integrated circuits, and is provided to monitor various signals, such as input and output voltages, and sub-control units, such as the controller in the DC/DC converter, of the uninterruptible power supply.
In the above circuit, when utility power is supplied from the power input ends normally, the average current mode controller
81
detects the current value of the input choke via the current transformer CT, and further drives the voltage boost unit
80
via the electronic switch Q to transform the input power for being supplied to the load.
When the utility power supplied from the power input ends is interrupted, the detection/control unit
83
will detect the interruption, and simultaneously activates the voltage mode controller
823
to control the DC/DC converter
821
, so as to convert the voltage of the battery set
822
into a higher voltage for being supplied to the load.
With such a conventional uninterruptible power supply, it is known that the average current mode controller is operated only when the utility power is normally supplied. When the utility power is interrupted, it is the voltage mode controller
823
that is used to control the DC/DC converter
821
to operate. However, the disadvantage of simply using the voltage mode controller
823
is that only the output voltage is controlled while the input current can not be controlled, resulting in a large root mean square (RMS) value of the input current, thus, having an higher loss and lower efficiency. It may be applicable to use the average current mode controller to control the DC/DC converter
821
to increase the efficiency, but unfortunately, the average current mode controller available in the market is designed for power factor correction (PFC). Thus it is suitable to operate when the utility power is normal. Such an average current mode controller is not appropriate for controlling the DC/DC converter shown in FIG.
Therefore, there is a desire to have an improved uninterruptible power supply to mitigate and/or obviate the aforementioned problems.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a high efficiency uninterruptible power supply, which supplies backup power in a average current control mode, so as to enhance the efficiency and increase the lifetime of the battery.
To achieve the object, the high efficiency uninterruptible power supply of the present invention comprises: a voltage boost unit to transform and boost the voltage of an input power for being supplied to the inverter; a backup power supply unit connected to output ends of the voltage boost unit; an average current mode controller for detecting a current value of the input power when the input power is normally supplied, and for detecting a current value of the backup power supply unit when the input power is interrupted; a voltage mode controller included in the backup power supply for controlling the backup power supply unit to output power based on the current value of the backup power supply unit detected by the average current mode controller; and a detection/control unit for detecting input and output voltages of the voltage boost unit, so as to determine whether to drive the average current mode controller and the voltage mode controller. This inverter converts DC bus voltage to sine-shape output.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4783728 (1988-11-01), Hoffman
patent: 5172009 (1992-12-01), Mohan
patent: 5334877 (1994-08-01), Mohan et al.
patent: 5781422 (1998-07-01), Lavin et al.
Berhane Adolf Deneke
Thorp Reed & Armstrong
LandOfFree
High efficiency uninterruptible power supply does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with High efficiency uninterruptible power supply, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High efficiency uninterruptible power supply will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2599287