US 5,099,410 A · Single phase AC power conversion apparatus

Abstract

A power conversion apparatus (20) circuit includes pairs of rectifying devices (48,49) connected together at a first node, a pair of capacitors (50, 51) connected together at a second node, and pairs of controllable switching devices (53,54) connected together at a third node, each of the pairs being connected in parallel by DC bus lines (58,59). The AC power source (21) is connected between the first and second nodes and the output voltage to a load (22) is provided between the first and third nodes. The switching devices (53,54) are controlled to switch on and off at proper times to provide a controllable output voltage to the load (22) which is at the same frequency as the input voltage and which may be controlled from zero to substantially twice the peak-to-peak input voltage. The output voltage waveform provided to the load can be filtered to provide a substantially sinusoidal waveform to the load. The power conversion apparatus (20) can also function as an uninterruptible power system by connecting an energy storage device, such as a large capacitor (140 ) or a battery (146) across the DC bus lines (58,59), and by controlling the charging of the energy storage device when power is available for the source and discharging the storage device when the power source fails.

Claims30

Dependent claims

Single phase AC power conversion apparatus for converting power from an AC power source at one frequency and voltage level to supply power to a load comprising:

(a) a pair of rectifying devices connected together at a first node, one rectifying device connected to conduct into the node and the other rectifying device connected to conduct away from the node;
(b) a pair of capacitors connected together at a second node;
(c) a pair of controllable turn-off and turn-on switching devices connected together at a third node;
(d) a pair of DC bus lines connecting the pairs of rectifying devices, capacitors and switching devices in parallel;
and
(e) control means for controlling the switching of the switching devices when the AC power source is connected to supply AC voltage between the first node and the second node such that the voltage between the third node and the first node, which is the output voltage provided to the load, differs from the voltage provided by the AC power source and is at the same frequency as the AC power source voltage.

3 more elements

Single phase AC power conversion apparatus for converting power from an AC power source at one frequency and voltage level to supply power to a load at the same frequency and at a controllable voltage level, comprising:

(a) a pair of rectifying devices connected together at a first node, one rectifying device connected to conduct into the node and the other rectifying device connected to conduct away from the node;
(b) a pair of capacitors connected together at a second node;
(c) a pair of controllable turn-off and turn-on switching devices connected together at a third node;
(d) a pair of DC bu lines connecting the paris of rectifying devices, capacitors and switching devices in parallel, voltage from the AC power source being provided between the first and second nodes and output voltage being provided between the first and third nodes;
(e) a filter connected between the first and third nodes to low pass filter the output voltage;
and
(f) control means for controlling the switching of the switching devices when the AC power source is connected to supply AC voltage between the first node and the second node such that the filtered output voltage provided between the third node and the first node to the load is controlled to a level between substantially zero and substantially twice the peak-to-peak voltage provided form the AC power source and at the same frequency as the AC power source voltage.

4 more elements

Single phase uninterruptible AC power conversion apparatus for converting power from an AC power source at one frequency and voltage level and supplying power to a load, comprising:

(a) a pair of rectifying devices connected together at a first node, one rectifying device connected to conduct into the node and the other rectifying device connected to conduct away from the node;
(b) a pair of capacitors connected together at a second node;
(c) a pair of controllable turn-off and turn-on switching devices connected together at a third node;
(d) a pair of DC bus lines connecting the pairs of rectifying devices, capacitors and switching devices in parallel, the voltage from the AC power source provided between the first and second nodes and the output voltage provided between the first and third nodes;
(e) a filter connected to low pass filter the output voltage provided between the first and third nodes to the load;
(f) a DC energy storage device connected across the DC bus lines;
and
(g) means for controlling the switching of the switching devices when the AC power source is connected to and is supplying AC voltage at a desired voltage level between the first node and the second node such that the output voltage between the third node and the first node is at a desired level between substantially zero and substantially twice the peak-to-peak voltage from the AC power source and at the same frequency as the AC power source voltage, and for inverting the DC voltage provided from the energy storage device to provide an AC voltage to the load when AC power from the AC power source fails.

5 more elements

Dependencies are inferred from the claim text.

Single phase AC power conversion apparatus

Life of this patent

Single phase AC power conversion apparatus

Life of this patent

Abstract

Claims30