Power device circuit topology based on coupled inductors

Abstract

According to an aspect of a coupled inductor based power device circuit topology of the present disclosure, an uninterruptible power supply (UPS) system is provided. The UPS system includes a first input configured to be coupled to an input power source, a second input configured to be coupled to an energy storage device, an output configured to provide output power, a power conversion circuit (PCC) configured to convert power received from at least one of the input power source or the energy storage device, an output circuit coupled to the PCC and the output, and a controller. The PCC includes a first inductor and a second inductor magnetically coupled with the first inductor. The controller is configured to control the PCC to provide direct current power originating from the input power source to the output circuit through the first inductor and to provide direct current power originating from the energy storage device to the output circuit through the first inductor and the second inductor.

Description

TECHNICAL FIELD

[0001] At least one example according to the present disclosure relates generally to power equipment. BACKGROUND

[0002] It is known to use power equipment, such as uninterruptible power supplies (UPSs), to provide stable, uninterrupted power to sensitive and / or critical loads, such as computer systems and other data processing systems. Known uninterruptible power supplies include online UPSs, offline UPSs, online interactive UPSs, and other types. Online UPSs provide regulated AC power and backup AC power when a primary source of AC power is interrupted. Offline UPSs generally do not provide regulation of input AC power, but provide backup AC power when the primary AC power source is interrupted. Online interactive UPSs are similar to offline UPSs in that they switch to battery power when the power goes out, but generally also include a multi-tap transformer to regulate the output voltage provided by the UPS. Some UPSs can contain multiple power conversion stages. SUMMARY

[0003] According to at least one aspect of the present disclosure, an uninterruptible power supply (UPS) system is provided. The UPS system includes a first input configured to be coupled to an input power source, a second input configured to be coupled to an energy storage device, an output configured to provide output power, a power conversion circuit configured to convert power received from at least one of the input power source or the energy storage device, the power conversion circuit including a primary branch having a first inductor and a backup branch having a second inductor magnetically coupled to the first inductor, an output circuit coupled to the power conversion circuit and to the output, and a controller coupled to the power conversion circuit and the output circuit and configured to control the power conversion circuit to provide DC power from the input power source to the output circuit through the first inductor in a normal operating mode and to control the power conversion circuit to provide DC power from the energy storage device to the output circuit through the first inductor and the second inductor in a backup operating mode.

[0004] In one embodiment, the output circuit includes a first capacitor configured to be coupled to the power conversion circuit and a second capacitor configured to be coupled to the power conversion circuit. In one embodiment, the primary branch portion includes a third inductor and the backup branch portion includes a fourth inductor, and wherein the third inductor is magnetically coupled to the fourth inductor. In at least one embodiment, the second inductor is coupled to a first switching device, and wherein the fourth inductor is coupled to a second switching device. In some embodiments, the controller is further configured to control the first switching device to charge a first capacitor and configured to control the second switching device to charge a second capacitor.

[0005] In at least one embodiment, the controller is further configured to control the first switching device to charge the first capacitor at a first rate and configured to control the second switching device to charge the second capacitor at a second rate different from the first rate. In some embodiments, the controller is further configured to control the first switching device and the second switching device to charge the first capacitor and the second capacitor simultaneously.

[0006] In some embodiments, controlling the first switching device to charge the first capacitor includes controlling the first switching device to enable the energy storage device to provide current to the second inductor, wherein providing current to the second inductor includes inducing a voltage across the first inductor, and controlling the first switching device to disable the energy storage device from providing current to the second inductor, wherein the first inductor is configured to discharge to the first capacitor in response to the switching device disabling the energy storage device.

[0007] In at least one embodiment, controlling the second switching device to charge the second capacitor includes controlling the second switching device to enable the energy storage device to provide current to the fourth inductor, wherein providing current to the fourth inductor includes inducing a voltage across the third inductor, and controlling the second switching device to disable the energy storage device from providing current to the fourth inductor, wherein the third inductor is configured to discharge to the second capacitor in response to the switching device disabling the energy storage device.

[0008] In some embodiments, the output power includes an output waveform having a positive portion and a negative portion, wherein the positive portion of the output waveform originates from power supplied through the first capacitor, and the negative portion of the output waveform originates from power supplied through the second capacitor. In one embodiment, the main branch portion is galvanically isolated from the backup branch portion. In some embodiments, the backup branch portion further includes: a switching device having: a first connection terminal coupled to the energy storage device; and a second connection terminal switchably coupled to the second inductor; and a diode having: an anode connection terminal coupled to the first connection terminal of the switching device; and a cathode connection terminal coupled to the second connection terminal of the switching device.

[0009] In at least one embodiment, the system further includes a switching device comprising: a first connection terminal coupled to the output terminal; and a second connection terminal configured to be coupled to one of the output circuit or the first input terminal, wherein the controller is configured to: control the switching device to connect the second connection terminal to the first input terminal in a bypass mode of operation; and to control the switching device to connect the second connection terminal to the output circuit in both a normal mode of operation and a backup mode of operation. In some embodiments, the system further includes: a first diode having: a cathode connection terminal coupled to the first inductor; and an anode connection terminal coupled to a reference node; and a second diode having: a cathode connection terminal coupled to the reference node; and an anode connection terminal coupled to the third inductor.

[0010] A system is provided according to at least one aspect of the present disclosure, the system comprising: a first input configured to be coupled to an alternating current (AC) power source; a second input configured to be coupled to an energy storage device; an output configured to provide output power derived from at least one of the first input or the second input; an output circuit coupled to the output, the output circuit comprising: a positive direct current (DC) bus and a negative DC bus; and a plurality of means for independently providing power derived from at least one of the first input or the second input to the positive DC bus and the negative DC bus.

[0011] In one embodiment, the output circuit includes a first capacitor and a second capacitor. In at least one embodiment, the system further includes: a plurality of means for charging the first capacitor at a first rate; and a plurality of means for charging the second capacitor at a second rate different from the first rate. In some embodiments, the system further includes: a plurality of means for simultaneously charging the first capacitor and the second capacitor. In one embodiment, the output power is AC power having a positive portion and a negative portion, wherein the positive portion of the output power originates from power supplied through the first capacitor, and wherein the negative portion of the output power originates from power supplied through the second capacitor. In some embodiments, the second input terminal is electrically isolated from the output circuit. In at least one embodiment, the system further includes a plurality of means for providing output power originating from the first input terminal to the output terminal and bypassing the output circuit.

[0012] According to at least one aspect of this disclosure, a non-transitory computer-readable medium is provided, the non-transitory computer-readable medium storing a sequence of computer-executable instructions for controlling an electrical device, the electrical device comprising: a first input terminal for receiving a first input power; a second input terminal for receiving a second input power; an output terminal for providing output power; an output circuit for providing the output power to the output terminal; and a power conversion circuit comprising: a main branch portion having a first inductor; and a spare branch portion having a second inductor, the second inductor being magnetically coupled. Coupled to the first inductor, wherein the computer-executable instruction sequence includes a plurality of instructions instructing at least one processor to control one or more switching devices in the power equipment to: receive the first input power through the first inductor in a normal operating mode; provide the first power derived from the first input power to the output circuit through the first inductor in the normal operating mode; receive the second input power through the second inductor in a standby operating mode; store the first stored energy derived from the second input power through the second inductor in the standby operating mode; store the second stored energy derived from the first stored energy through the first inductor in the standby operating mode; and provide the second power derived from the second stored energy to the output circuit through the first inductor in the standby operating mode.

[0013] In some embodiments, the output circuit includes a first capacitor and a second capacitor; wherein the main branch portion further includes a third inductor; wherein the spare branch portion includes a fourth inductor magnetically coupled to the third inductor; wherein the computer-executable instruction sequence further includes a plurality of instructions instructing the at least one processor to control the one or more switching devices to provide a first charging current to the first capacitor and a second charging current to the second capacitor through the first inductor and the third inductor.

[0014] In at least one embodiment, the computer-executable instruction sequence further includes a plurality of instructions instructing at least one processor to control the one or more switching devices to provide the first charging current to the first capacitor at a first rate and to provide the second charging current to the second capacitor at a second rate, wherein the first rate is different from the second rate, and wherein the first charging current and the second charging current are provided simultaneously.

[0015] In some embodiments, the power equipment further includes a switching device having: a first connection terminal coupled to the output terminal; and a second connection terminal configured to be coupled to one of the output circuit or the first input terminal, wherein the computer-executable instruction sequence further includes a plurality of instructions instructing the at least one processor to: control the switching device to connect the second connection terminal to the first input terminal in a bypass operation mode; and control the switching device to connect the second connection terminal to the output circuit in the normal operation mode and the standby operation mode. Attached Figure Description

[0016] Various aspects of at least one embodiment are discussed below with reference to the accompanying drawings, which are not drawn to scale. The drawings are included to provide illustration and further understanding of the aspects and embodiments, and are incorporated in and form a part of this specification, but are not intended to be limiting definitions of any particular embodiment. The drawings, along with the remainder of the specification, serve to explain the principles and operation of the described and claimed aspects and embodiments. In the drawings, the same or nearly identical components shown in the various figures are represented by similar numbers. For clarity, not every component can be labeled in every figure. In the figures:

[0017] Figure 1 The circuit diagram of a typical online UPS is shown;

[0018] Figure 2 A schematic diagram of a UPS according to one embodiment is shown;

[0019] Figure 3The process of controlling a UPS according to one embodiment is shown;

[0020] Figure 4 A circuit diagram of a UPS including a first current path according to one embodiment is shown;

[0021] Figure 5 A circuit diagram of a UPS including a second current path according to one embodiment is shown;

[0022] Figure 6 A circuit diagram of a UPS including a third current path according to one embodiment is shown;

[0023] Figure 7 A circuit diagram of a UPS including a fourth current path according to one embodiment is shown;

[0024] Figure 8 A circuit diagram of a UPS including a fifth current path according to one embodiment is shown;

[0025] Figure 9 A circuit diagram of a UPS including a sixth current path according to one embodiment is shown;

[0026] Figure 10 A circuit diagram of a UPS including a seventh current path according to one embodiment is shown;

[0027] Figure 11 A circuit diagram of a UPS including an eighth current path according to one embodiment is shown;

[0028] Figure 12 A schematic diagram of a UPS according to one embodiment is shown;

[0029] Figure 13 A schematic diagram of a UPS according to one embodiment is shown; and

[0030] Figure 14 A schematic diagram of a UPS according to one embodiment is shown. Detailed Implementation

[0031] The examples of the methods and systems discussed herein are not limited in application to the details of the construction and arrangement of the components set forth in the following description or illustrated in the accompanying drawings. The methods and systems can be implemented and practiced or carried out in various ways in other embodiments. The specific implementation examples provided herein are for illustrative purposes only and are not intended to be limiting. In particular, the behavior, components, or features discussed in connection with any one or more examples or embodiments are not intended to exclude similar effects in other examples.

[0032] Furthermore, the wording and terminology used herein are for descriptive purposes only and should not be considered limiting. Any reference in the singular to an instance, embodiment, component, element, or behavior of a system or method may include multiple embodiments, and any reference in the plural to any embodiment, component, element, or behavior may include only the singular embodiments. References in either the singular or plural form are not intended to limit the systems or methods, their components, behaviors, or elements currently disclosed. The terms “including,” “comprising,” “having,” “containing,” “involving,” and their variations as used herein mean to include the items listed herein and their equivalents, as well as additional items. The reference “or” can be interpreted as inclusive, such that any item described using “or” can indicate a single described item, more than one described item, or any one of all described items. Furthermore, if there is any inconsistency in the use of terminology between this document and a document incorporated herein by reference, the terminology used in the incorporated feature shall supplement this document; for irreconcilable differences, the terminology used in this document shall prevail.

[0033] As mentioned above, some UPS systems, including online UPS systems, may include multiple power conversion stages. For example, a typical online UPS may include an input PFC converter and a separate DC / DC converter coupled to an energy storage device to convert the input AC power and the stored DC power, respectively. Figure 1 A circuit diagram of a conventional online UPS 100 including multiple input power conversion stages is shown. The online UPS 100 includes a PFC converter 102, a DC / DC converter 104, an inverter 106, and a controller 107. The input of the PFC converter 102 is configured to be coupled to an AC power source 108, and the output of the PFC converter 102 is coupled to the inverter 106 via a first DC bus 110 and a second DC bus 112. The DC / DC converter 104 is configured to be coupled to an energy storage device 114 and is coupled to the inverter 106 via the first DC bus 110 and the second DC bus 112. The inverter 106 is configured to be coupled to a load 116 and to provide output power to the load 116. The controller 107 is communicatively coupled to one or more switching devices (e.g., multiple transistors) in the UPS 100 and can provide control signals to one or more switching devices (e.g., multiple transistors) in the UPS 100.

[0034] In response to receiving input AC power from AC power source 106, PFC converter 102 is configured to convert the received AC power into DC power and supply the DC power to inverter 106 via first DC bus 110 and second DC bus 112. If energy storage device 114 is not fully charged, PFC converter 102 can also supply a portion of the DC power to DC / DC converter 104 to charge energy storage device 114 via first DC bus 110 and second DC bus 112.

[0035] In response to the AC power supply 106 failing to provide sufficient AC power to the PFC converter 102 (e.g., due to a power outage or power failure), the DC / DC converter 104 can be configured to enter a standby operation mode. In standby operation mode, the DC / DC converter 104 can be configured to draw backup DC power from the energy storage device 114, convert the backup DC power into converted DC power (e.g., by changing the voltage level of the energy stored in the energy storage device 114), and supply the converted DC power to the inverter 106 via the first DC bus 110 and the second DC bus 112. The inverter 106 is configured to convert the DC power from the first DC bus 110 and the second DC bus 112 (as described above, originating from at least one of the input AC power supply or the backup DC power supply) into output AC power, and the output AC power is supplied to the load 116.

[0036] The size, component count, and cost of a conventional online UPS 100 can be disadvantageously high, partly because the PFC converter 102 and DC / DC converter 104 are implemented as separate converters. When the DC / DC converter 104 is active, the PFC converter 102 may be inactive, and vice versa. Therefore, it is advantageous to provide an online UPS capable of performing the functions of both the PFC converter 102 and the DC / DC converter 104 without prolonged inactivity, thereby reducing the size, component count, and cost of such converters.

[0037] A conventional online UPS 100 can also be disadvantageous because the power supplied to the first DC bus 110 and the second DC bus 112 is typically not independently controlled in standby operation mode. For example, the power supplied to the first DC bus 110 and the second DC bus 112 by the PFC converter 102 and the DC / DC converter 104 is provided in equal proportions, regardless of the demand of the load 116. This can lead to inefficient operation of the conventional online UPS 100. For example, a conventional online UPS 100 may not be able to effectively supply power to loads that require uneven power distribution from buses 110 and 112 in standby operation mode, such as loads that require primarily drawing half-wave rectified waveforms from the first DC bus 110.

[0038] In view of the foregoing, conventional online UPS 100s can be disadvantageously expensive, large, and inflexible. Therefore, this disclosure provides a topology that addresses at least some of the aforementioned drawbacks to reduce costs and improve UPS efficiency.

[0039] Figure 2 A schematic diagram of a UPS 200 according to one embodiment described herein is shown. The UPS 200 includes a dual converter 202, an inverter 204, and a controller 205. The dual converter 202 is configured to be coupled to an AC power supply 206 and to the inverter 204. The inverter 204 is coupled to the dual converter 202 and can be configured to be coupled to a load.

[0040] The dual converter 202 includes a main branch 208 and a backup branch 210. The main branch 208 includes a first relay 212, a first diode 214, a second diode 216, a first inductor 218, a second inductor 220, a first switching device 222, a third diode 224, and a fourth diode 226. The backup branch 210 includes an energy storage device 228, a second relay 230, a third inductor 232, a fourth inductor 234, a second switching device 236, and a third switching device 238. In some examples, the energy storage device 228 may be external to the dual converter 202 and may be coupled to the backup branch 210. The inverter 204 may include a fifth diode 240, a sixth diode 242, a first capacitor 244, a second capacitor 246, a fourth switching device 248, a fifth switching device 250, a fifth inductor 252, and a third capacitor 254.

[0041] In some embodiments, other inverter topologies may be implemented, alternative to or in addition to the topology shown for connecting inverter 204. In other embodiments, inverter 204 may be omitted, such that UPS 200 provides DC instead of AC output power. In other embodiments, components 240 to 254 of inverter 204 may be as follows: Figure 2 The implementation is shown, but switching devices 248 and 250 are operated to provide DC rather than AC output power. For example, while providing output power to load 256, only one of the switching devices 248 and 250 can be closed and turned on, such that power with only one voltage polarity is provided to load 256. Therefore, although components 240 to 254 are described as components of inverter 204 in one example, components 240 to 254 can be operated to provide the required or desired DC or AC output power rate of load 256. Inverter 204, or the circuit implemented in place of inverter 204, may be referred to herein as the "output circuit".

[0042] In at least one embodiment, the first relay 212 is configured as a single-pole double-throw switching device having a first terminal, a second terminal, and a third terminal. The third terminal is configured to be switchably connected to one of the first and second terminals. The first terminal is configured to be coupled to an AC power supply 206. The second terminal is coupled to a reference node 213 (e.g., a node at a reference voltage such as ground). The third terminal is configured to be coupled to a first diode 214 and a second diode 216. The first diode 214 has an anode coupled to the first relay 212 and the second diode 216, and a cathode coupled to a first inductor 218. The second diode 216 has a cathode coupled to the first relay 212 and the first diode 214, and an anode coupled to a second inductor 220.

[0043] The first inductor 218 is coupled to the first diode 214 at a first connection terminal and to the first switching device 222, the third diode 224, and the fifth diode 240 at a second connection terminal. The first inductor 218 is also configured to be magnetically coupled to the third inductor 232. As used herein, “magnetically coupled” can refer to the relationship between at least two inductive components, wherein a magnetic field generated by the first inductive component and / or a change in the magnetic field induces a voltage across a second inductive component (also referred to as “inducing a voltage across the second inductive component”) (e.g., mutual inductance).

[0044] The second inductor 220 is coupled to the second diode 216 at a first connection terminal, and to the first switching device 222, the fourth diode 226, and the sixth diode 242 at a second connection terminal. The second inductor 220 is also configured to be magnetically coupled to the fourth inductor 234. The first switching device 222 is coupled to the first inductor 218, the third diode 224, and the fifth diode 240 at a first connection terminal, and to the second inductor 220, the fourth diode 226, and the sixth diode 242 at a second connection terminal, and is configured to be communicatively coupled to the controller 205 at a control connection terminal. The third diode 224 includes a cathode connection terminal coupled to the first inductor 218, the first switching device 222, and the fifth diode 240, and an anode connection terminal coupled to the fourth diode 226 and the reference node 213. The fourth diode 226 includes a cathode connection coupled to the third diode 224 and the reference node 213, and an anode connection coupled to the second inductor 220, the first switching device 222 and the sixth diode 242.

[0045] Energy storage device 228 is coupled to a second relay 230 at a first connection terminal, and to a second switching device 236 and a third switching device 238 at a second connection terminal. In at least one embodiment, the second relay 230 is configured as a single-pole single-throw switch having a first terminal, a second terminal, and a third terminal. The third terminal is configured to be switchably connected to one of the first and second terminals. The first terminal is configured to be coupled to a third inductor 232 and a fourth inductor 234. In one embodiment, the second terminal may not be permanently connected to any other component and is configured to be switchably connected to the third terminal. Therefore, in one embodiment, current does not flow through the second terminal. The third terminal is configured to be coupled to energy storage device 228. In some examples, energy storage device 228 may be coupled to a charger (not shown) configured to charge energy storage device 228. For example, the charger may be coupled in parallel with energy storage device 228.

[0046] The third inductor 232 is coupled to the second relay 230 at the first connection terminal and to the second switching device 236 at the second connection terminal. The fourth inductor 234 is coupled to the second relay 230 at the first connection terminal and to the third switching device 238 at the second connection terminal. The second switching device 236 is coupled to the third inductor 232 at the first connection terminal, to the energy storage device 228 at the second connection terminal, and is configured to communicatively couple to the controller 205 at the control connection terminal. The third switching device 238 is coupled to the fourth inductor 234 at the first connection terminal, to the energy storage device 228 at the second connection terminal, and is configured to communicatively couple to the controller 205 at the control connection terminal.

[0047] The fifth diode 240 has: an anode coupled to the first inductor 218, the first switching device 222, and the third diode 224; and a cathode coupled to the first capacitor 244 and the fourth switching device 248. The sixth diode 242 has: a cathode coupled to the second inductor 220, the first switching device 222, and the fourth diode 226; and an anode coupled to the second capacitor 246 and the fifth switching device 250. The first capacitor 244 is coupled to the fifth diode 240 and the fourth switching device 248 at a first connection terminal and to the reference node 213 at a second connection terminal. The second capacitor 246 is coupled to the reference node 213 at a first connection terminal and to the sixth diode 242 and the fifth switching device 250 at a second connection terminal.

[0048] The fourth switching device 248 is coupled to the fifth diode 240 and the first capacitor 244 at the first connection terminal, coupled to the fifth switching device 250 and the fifth inductor 252 at the second connection terminal, and configured to communicatively couple to the controller 205 at the control connection terminal. The fifth switching device 250 is coupled to the fourth switching device 248 and the fifth inductor 252 at the first connection terminal, coupled to the sixth diode 242 and the second capacitor 246 at the second connection terminal, and configured to communicatively couple to the controller 205 at the control connection terminal.

[0049] The fifth inductor 252 is coupled to the fourth switching device 248 and the fifth switching device 250 at a first connection terminal, and configured to be coupled to the third capacitor 254 at a second connection terminal. The third capacitor 254 is coupled to the fifth inductor 252 at the first connection terminal and to the reference node 213 at the second connection terminal. In some examples, the third capacitor 254 may be configured to be coupled to a load external to the UPS 200. For example, the third capacitor 254 may be configured to be coupled in parallel with the load.

[0050] Dual converter 202 is configured to receive input power from at least one of AC power source 206 and energy storage device 228, convert the received power into DC power (e.g., from AC power or DC power at a different voltage level), and supply the converted DC power to inverter 204. Inverter 204 is configured to receive DC power from dual converter 202, convert the received DC power into output AC power, and supply the output AC power to a load. Controller 205 is configured to control dual converter 202 and inverter 204. For example, controlling the operation of dual converter 202 and inverter 204 may include controlling the switching operations of first switching device 222, second switching device 236, third switching device 238, fourth switching device 248, and fifth switching device 250.

[0051] The controller 205 can determine the operating mode of the UPS 200 and, based on this operating mode, control the dual converter 202 to draw power from at least one of the AC power source 206 or the energy storage device 228. For example, the controller 205 can determine the power quality (e.g., voltage, current, frequency, etc.) provided by the AC power source 206 based on one or more parameters indicated by the power quality received from the AC power source 206. Determining the power quality provided by the AC power source 206 may include, for example, determining whether the parameters indicated by the power quality (e.g., voltage or current parameters) are within permissible ranges.

[0052] If the power quality parameters are within permissible ranges, controller 205 can determine that UPS 200 is in normal operating mode, characterized at least in part by UPS 200 receiving qualified power from AC power source 206. In normal operating mode, controller 205 can control dual converter 202 to draw power from AC power source 206. If the power quality parameters are outside permissible ranges, controller 205 can determine that UPS 200 is in standby operating mode, characterized at least in part by UPS 200 being unable to receive qualified power from AC power source 206. In standby operating mode, controller 205 can control dual converter 202 to draw power from energy storage device 228.

[0053] Figure 3 A process 300 for controlling a UPS 200 according to an embodiment is shown. At action 302, process 300 begins. At action 304, it is determined whether the UPS 200 is in a normal operating mode. For example, as described above, controller 205 may determine whether the UPS 200 is in a normal operating mode based on one or more parameters indicated by the power quality provided by AC power supply 206. If controller 205 determines that the UPS 200 is in a normal operating mode (action 304 is yes), process 300 continues to action 306.

[0054] In action 306, controller 205 controls first relay 212 and second relay 230. Controlling first relay 212 includes connecting a third terminal of first relay 212 to a first terminal of first relay 212, so that AC power 206 is coupled through first relay 212 to first diode 214 and second diode 216. Controlling second relay 230 includes connecting a third terminal of second relay 230 to a second terminal of second relay 230, thereby disconnecting energy storage device 228 from third inductor 232 and fourth inductor 234.

[0055] At action 308, the first inductor 218 is energized. In one embodiment, at action 308, the first inductor 218 is energized by AC power received from AC power source 206, wherein the AC power is in the positive half-cycle of a sinusoidal waveform. In one example, during the positive half-cycle of the power supplied by AC power source 206, the first diode 214 is forward-biased and the second diode 216 is reverse-biased. Energizing the first inductor 218 includes controlling the first switching device 222 via controller 205 to alternate between an open and non-conducting position and a closed and conducting position. Controller 205 can control the first switching device 222 based on the power received from AC power source 206. For example, controller 205 can control first switching device 222 to maintain a sinusoidal current from AC power supply 206 through first switching device 222.

[0056] When the first switching device 222 is in the closed and on position, AC power supplied by the AC power source 206 is delivered to the conductive path including the AC power source 206, the first relay 212, the first diode 214, the first inductor 218, the first switching device 222, and the fourth diode 226. Figure 4 The circuit diagram of the UPS 200 is shown, indicating the current path 400 at operation 308.

[0057] In action 310, the first inductor 218 is de-energized. For example, action 310 includes controlling the first switching device 222 via controller 205 to transition from a closed and conducting position to an open and non-conducting position, thereby interrupting the current path 400. The first inductor 218 discharges into a conductive path including AC power supply 206, first relay 212, first diode 214, first inductor 218, fifth diode 240, and first capacitor 244 to charge the first capacitor 244. Figure 5 A circuit diagram of a UPS 200 is shown, indicating the current path 500 at operation 310.

[0058] As described above, the first inductor 218 is magnetically coupled to the third inductor 232. However, during operations 308 and 310, the second switching device 236 is held in the off and non-conducting position. Therefore, although a voltage is induced across the third inductor 232, no induced current flows through the third inductor 232, at least during operations 308 and 310, because the third inductor 232 is coupled in series with the off and non-conducting second switching device 236.

[0059] At action 312, the second inductor 220 is energized. In one embodiment, at action 312, the second inductor 220 is energized by power received from AC power source 206, wherein the AC power supplied by AC power source 206 is in the negative half-cycle of a sine wave. In one example, during the negative half-cycle of the power supplied by AC power source 206, the first diode 214 is reverse biased and the second diode 216 is forward biased. Energizing the second inductor 220 may include controlling the first switching device 222 to a closed and on position by the controller 205, so as to deliver power supplied by AC power source 206 to a conductive path including AC power source 206, second diode 216, second inductor 220, first switching device 222 and third diode 224. Controlling the first switching device 222 at action 312 may be performed similarly to controlling the first switching device 222 discussed above with respect to action 308. Figure 6 The circuit diagram of the UPS 200 is shown, indicating the current path 600 at operation 312.

[0060] In action 314, the second inductor 220 is de-energized. For example, action 314 includes controlling the first switching device 222 from a closed and conducting position to an open and non-conducting position via controller 205, thereby interrupting the current path 600. The second inductor 220 discharges into a conductive path including AC power supply 206, first relay 212, second diode 216, second inductor 220, sixth diode 242, and second capacitor 246 to charge the second capacitor 246. Figure 7 The circuit diagram of the UPS 200 is shown, indicating the current path 700 at operation 314.

[0061] As described above, the second inductor 220 is magnetically coupled to the fourth inductor 234. However, during operations 312 and 314, the third switching device 238 is held in the off and non-conducting position. Accordingly, although a voltage is induced across the fourth inductor 234, no induced current flows through the fourth inductor 234, at least during operations 312 and 314, at least because the fourth inductor 234 is coupled in series with the off and non-conducting third switching device 238.

[0062] Therefore, actions 308 and 310 are performed during the positive half-cycle of the input power received from AC power source 206 to charge the first capacitor 244, and actions 312 and 314 are performed during the negative half-cycle of the input power received from AC power source 206 to charge the second capacitor 246. The inverter 204 can be controlled during actions 308 to 314 to draw power from the first capacitor 244 and the second capacitor 246, convert the power into AC power, and supply the AC power to the output. For example, the controller 205 can use pulse width modulation (PWM) in conjunction with control signals provided to switching devices 248 and 250 to supply AC power to the output. After action 314, process 300 returns to action 304.

[0063] In response to determining that the UPS 200 is still in normal operating mode (action 304 is yes), actions 306 to 314 are repeated. In response to determining that the UPS 200 is not in normal operating mode (action 304 is no), process 300 continues to action 316. In action 316, controller 205 controls first relay 212 and second relay 230. Controlling first relay 212 may include connecting a third terminal of first relay 212 to a second terminal of first relay 212 to disconnect AC power supply 206 from UPS 200, and first diode 214 and second diode 216 coupled to reference node 213. Controlling second relay 230 may include connecting a third terminal of second relay 230 to a first terminal of second relay 230 to connect energy storage device 228 to third inductor 232 and fourth inductor 234.

[0064] In action 318, the first inductor is energized. For example, action 318 may include controller 205 controlling the second switching device 236 to a closed and on position to energize the third inductor 232. Because the third inductor 232 is magnetically coupled to the first inductor 218, a voltage is induced across the first inductor 218, thereby energizing the magnetically coupled first inductor 218. Energizing the third inductor 232, so that the first inductor 218 may include: supplying power to the third inductor 232 through the energy storage device 228 in a conductive path including the energy storage device 228, the second relay 230, the third inductor 232, and the second switching device 236. Figure 8 The circuit diagram of UPS200 is shown, indicating the current path 800 at operation 318.

[0065] Although the first inductor 218 is energized by the magnetically coupled third inductor 232, the first diode 214 prevents the first inductor 218 from discharging. The induced voltage across the first inductor 218 reverse-biases the first diode 214, which is coupled in series with the first inductor 218, thereby preventing any induced current from flowing through the first inductor 218 during operation 318.

[0066] In action 320, the first inductor is de-energized. For example, action 320 may include controlling the second switching device 236 to an open and non-conductive position via controller 205, thereby preventing the energy storage device 228 from discharging to the third inductor 232. In response to the cessation of current flow through the third inductor 232, the polarity of the induced voltage across the first inductor 218 is reversed, thereby forward biasing the first diode 214.

[0067] Therefore, the first inductor 218 can release current to a conductive path including the first relay 212, the first diode 214, the first inductor 218, the fifth diode 240, and the first capacitor 244 to charge the first capacitor 244. Figure 9 The circuit diagram of UPS200, which indicates the current path 900 at action 320, is shown.

[0068] In action 322, the second inductor is energized. For example, action 322 may include the controller 205 controlling the third switching device 238 to be in a closed and on position to energize the fourth inductor 234. Because the fourth inductor 234 is magnetically coupled to the second inductor 220, a voltage is induced across the second inductor 220, thereby energizing the magnetically coupled second inductor 220.

[0069] The fourth inductor 234 is energized, so that the second inductor 220 may include: supplying power to the fourth inductor 234 through the energy storage device 228 in a conductive path including the energy storage device 228, the second relay 230, the fourth inductor 234 and the third switching device 238. Figure 10 A circuit diagram of a UPS 200 is shown, indicating the current path 1000 at operation 322.

[0070] Although the second inductor 220 is energized by the magnetically coupled fourth inductor 234, the second diode 216 prevents the second inductor 220 from discharging. The induced voltage across the second inductor 220 reverse-biases the second diode 216, which is coupled in series with the second inductor 220, thereby preventing any induced current from flowing through the second inductor 220 during operation 322.

[0071] In action 324, the second inductor is de-energized. For example, action 324 may include the controller 205 controlling the third switching device 238 to be in an open and non-conductive position, thereby preventing the energy storage device 228 from discharging to the fourth inductor 234. In response to the cessation of current flow through the fourth inductor 234, the polarity of the induced voltage across the second inductor 220 is reversed, thereby forward biasing the second diode 216.

[0072] Therefore, the second inductor 220 can release current to a conductive path including the first relay 212, the second diode 216, the second inductor 220, the sixth diode 242, and the second capacitor 246 to charge the second capacitor 246. Figure 11 A circuit diagram of a UPS 200 is shown, indicating the current path 1100 at operation 324.

[0073] Therefore, actions 318 and 320 are executed to provide input power from energy storage device 228 to charge the first capacitor 244, and actions 322 and 324 are executed to provide input power from energy storage device 228 to charge the second capacitor 246. During the execution of actions 318 to 324, inverter 204 can be controlled to draw power from the first capacitor 244 and the second capacitor 246, convert the power to AC power, and provide the AC power to the output. For example, controller 205 can use pulse width modulation (PWM) in conjunction with control signals provided to switching devices 248 and 250 to provide AC power to the output. After action 324, process 300 returns to action 304.

[0074] Therefore, process 300 can be performed by UPS 200 to provide output power to the load during normal operation (e.g., when the quality of the AC power received from AC power source 206 is acceptable) and during standby operation (e.g., when the quality of the AC power received from AC power source 206 is unacceptable). As mentioned above, UPS 200 may be advantageous compared to some UPSs, such as conventional online UPS 100, at least because it reduces the number of components compared to conventional online UPS 100. Therefore, the cost and physical footprint of UPS 200 can be reduced compared to conventional online UPS 100.

[0075] In at least one embodiment, the main branch 208 may be galvanically isolated from the backup branch 210. As used herein, “galvanically isolated” can refer to a relationship between at least two components where there is no direct current path between them. For example, the main branch 208 may be magnetically coupled to the backup branch 210 through the first inductor 218, the second inductor 220, the third inductor 232, and the fourth inductor 234, but there is no direct current path through a physically conductive medium (e.g., wires, buses, or other solid conductors). Furthermore, the main branch 208 and the backup branch 210 may not share a common ground or return connection. Therefore, the main branch 208 may be referred to herein as galvanically isolated from the backup branch 210.

[0076] Furthermore, the amount of power supplied to the first capacitor 244 and the second capacitor 246 can be controlled independently. For example, during normal operation, the amount of power supplied to the first capacitor 244 at operation 310 (e.g., the amount of power supplied during the positive half-cycle of the input AC power) can be proportional to the amount of energy supplied to the first inductor 218 at operation 308. The amount of energy supplied to the first inductor 218 can also be proportional to the duration for which the first switching device 222 is controlled in the closed and on position (e.g., by controlling the duty cycle of the control signal supplied to the first switching device 222 by the controller 205). Therefore, the amount of power supplied to the first capacitor 244 at operation 310 can be controlled independently by the controller 205 at operation 308.

[0077] A similar principle applies to the amount of power supplied to the second capacitor 246 at operations 312 and 314. For example, during normal operation, the amount of power supplied to the second capacitor 246 at operation 314 (e.g., the amount of power supplied during the negative half-cycle of the input AC power) can be proportional to the amount of energy supplied to the second inductor 220 at operation 312. The amount of energy supplied to the second inductor 220 can, in turn, be proportional to the duration for which the first switching device 222 is in the closed and on position (e.g., by controlling the duty cycle of the control signal supplied to the first switching device 222 by the controller 205). Therefore, the amount of power supplied to the second capacitor 246 at operation 314 can be controlled by the controller 205 at operation 312.

[0078] In some embodiments, the first capacitor 244 and the second capacitor 246 can be charged and discharged individually. As used herein, "individual charging and discharging" can refer to charging or discharging a component without directly affecting or being constrained by another component. Thus, the first capacitor 244 can be charged or discharged at a first rate, and the second capacitor 246 can be charged or discharged at a second rate, wherein the first rate is independent of the second rate.

[0079] During standby operation, the amount of power supplied to the first capacitor 244 at operation 318 (e.g., the amount of power supplied to the first capacitor 244 by the energy storage device 228) can be proportional to the amount of energy supplied to the first inductor 218 at operation 318. The amount of energy supplied to the first inductor 218 can also be proportional to the duration for which the second switching device 236 is in a closed and on position (e.g., by controlling the duty cycle of the control signal supplied to the second switching device 236 by the controller 205), thereby energizing the third inductor 232. Therefore, the amount of power supplied to the first capacitor 244 at operation 320 can be controlled by the controller 205 at operation 318.

[0080] A similar principle applies to the amount of power supplied to the second capacitor 246 at actions 322 and 324. For example, during standby operation, the amount of power supplied to the second capacitor 246 at action 324 (e.g., the amount supplied to the second capacitor 246 by the energy storage device 228) can be proportional to the amount of power supplied to the second inductor 220 at action 322. The amount of energy supplied to the second inductor 220 can also be proportional to the duration for which the third switching device 238 is controlled to be in the closed and open position (e.g., by controlling the duty cycle of the control signal supplied to the third switching device 238 by the controller 205). Therefore, the amount of power supplied to the second capacitor 246 at action 324 can be controlled by the controller 205 at action 322.

[0081] The amount of power supplied to the first capacitor 244 and the amount of power supplied to the second capacitor 246 can be controlled independently. This individual control over the amount of power supplied to the first capacitor 244 and the second capacitor 246 allows the UPS 200 to respond more effectively to load demands. For example, if the UPS 200 supplies positive voltage power to a load requiring rectified power, the UPS 200 can supply additional power to the first capacitor 244 to compensate for the increased amount of power drawn from the first capacitor 244 by the inverter 206, thereby generating rectified power.

[0082] Figure 12 A schematic diagram of a UPS 1200 according to an embodiment is shown. The UPS 1200 includes a dual converter 1202, an inverter 1204, and a controller 1205. The dual converter 1202 is configured to be coupled to an AC input 1206 and to the inverter 1204. The inverter 1204 is coupled to the dual converter 1202 and can be configured to be coupled to a load. The dual converter 1202 includes a main branch 1208 and a standby branch 1210.

[0083] UPS 1200 is similar to UPS 200. For example, inverter 1204, controller 1205, and main branch 1208 are similar to inverter 204, controller 205, and main branch 208. Backup branch 1210 is similar to backup branch 210, wherein the second switchgear 236 and the third switchgear 238 in backup branch 210 are replaced by a single switchgear in backup branch 1210.

[0084] More specifically, the backup branch 1210 includes an energy storage device 1212, a relay 1214, a first inductor 1216, a second inductor 1218, and a switching device 1220. The energy storage device 1212 is coupled to the relay 1214 at a first connection terminal and to the switching device 1220 at a second connection terminal. The relay 1214 is configured as a single-pole single-throw switch having a first terminal, a second terminal, and a third terminal. The third terminal is configured to be switchably connected to one of the first and second terminals. The first terminal is configured to be coupled to the first inductor 1216 and the second inductor 1218. In one embodiment, the second terminal may not be permanently connected to any other component and is configured to be switchably connected to the third terminal. Therefore, in one embodiment, current does not flow through the second terminal. The third terminal is configured to be coupled to the energy storage device 1212.

[0085] A first inductor 1216 is coupled to a relay 1214 at a first connection terminal and to a switching device 1220 at a second connection terminal. A second inductor 1218 is coupled to the relay 1214 at a first connection terminal and to the switching device 1220 at a second connection terminal. The switching device 1220 is coupled to the first inductor 1216 and the second inductor 1218 at a first connection terminal, coupled to an energy storage device 1212 at a second connection terminal, and configured to communicatively couple to a controller 1205 at a control connection terminal.

[0086] In some examples, UPS 200 and UPS 1200 are configured to operate in a similar manner. For example, UPS 200 and 1200 can operate in a substantially similar manner during normal operating mode. During standby operating mode, because the first inductor 1216 and the second inductor 1218 are connected to a single shared switching device 1220, the first inductor 1216 and the second inductor 1218 are not independently energized. In other words, the first inductor 1216 is not energized without energizing the second inductor 1218, and the second inductor 1218 is not energized without energizing the first inductor 1216.

[0087] Conversely, by closing the second switch device 236 and opening the third switch device 238, the third inductor 232 can be energized independently of the fourth inductor 234, and by closing the third switch device 238 and opening the second switch device 236, the fourth inductor 234 can be energized independently of the third inductor 232. However, the number of components in UPS 1200 is less than that in UPS 200, at least because the number of switches is reduced by one, thereby reducing the cost and space required for UPS 1200 compared to UPS 200.

[0088] Figure 13A schematic diagram of a UPS 1300 according to an embodiment is shown. The UPS 1300 includes a dual converter 1302, an inverter 1304, and a controller 1305. The dual converter 1302 is configured to be coupled to an AC input 1306 and to the inverter 1304. The inverter 1304 is coupled to the dual converter 1302 and can be configured to be coupled to a load. The dual converter 1302 includes a main branch 1308 and a standby branch 1310.

[0089] UPS 1300 is similar to UPS 200. For example, inverter 1304 and controller 1305 are similar to inverter 204 and controller 205. The main branch 1308 is similar to main branch 208 and has two additional diodes, and the standby branch 1310 is similar to standby branch 210 and has additional diodes. More specifically, main branch 1308 includes a first relay 1312, a first diode 1314, a second diode 1316, a third diode 1318, a fourth diode 1320, a first inductor 1322, a second inductor 1324, a first switching device 1326, a fifth diode 1328, and a sixth diode 1330. Standby branch 1310 includes an energy storage device 1332, a second relay 1334, a seventh diode 1336, a third inductor 1338, a fourth inductor 1340, a second switching device 1342, and a third switching device 1344. In another embodiment, the primary branch 1308 may be replaced by an alternative topology such as the primary branch 208. In yet another embodiment, the backup branch 1310 may be replaced by an alternative topology such as the backup branch 210.

[0090] The first relay 1312 is configured as a single-pole double-throw switching device having a first terminal, a second terminal, and a third terminal. The third terminal is configured to be switchably connected to one of the first and second terminals. The first terminal is configured to be coupled to an AC input terminal 1306. The second terminal is coupled to a reference node 1313 (e.g., a node at a reference voltage such as ground). The third terminal is configured to be coupled to a first diode 1314 and a second diode 1316. The first diode 1314 has: an anode coupled to the first relay 1312 and the second diode 1316; and a cathode coupled to a first inductor 1322 and a third diode 1318. The second diode 1316 has: a cathode coupled to the first relay 1312 and the first diode 1314; and an anode coupled to a fourth diode 1320 and a second inductor 1324.

[0091] The third diode 1318 has: a cathode coupled to the first diode 1314 and the first inductor 1322; and an anode coupled to the fourth diode 1320 and the reference node 1313. The fourth diode 1320 has: a cathode coupled to the third diode 1318 and the reference node 1313; and an anode coupled to the second diode 1316 and the second inductor 1324. The first inductor 1322 is coupled to the first diode 1314 and the third diode 1318 at a first connection terminal, and to the first switching device 1326, the fifth diode 1328, and the eighth diode 1346 of the inverter 1304 at a second connection terminal. The first inductor 1322 is also configured to be magnetically coupled to the third inductor 1338 of the spare branch 1310.

[0092] The second inductor 1324 is coupled at the first connection terminal to the second diode 1316 and the fourth diode 1320, and at the second connection terminal to the first switching device 1326, the sixth diode 1330, and the ninth diode 1348 of the inverter 1304. The second inductor 1324 is also configured to be magnetically coupled to the fourth inductor 1340 of the spare branch 1310. The first switching device 1326 is coupled at the first connection terminal to the first inductor 1322, the fifth diode 1328, and the eighth diode 1346, at the second connection terminal to the second inductor 1324, the sixth diode 1330, and the ninth diode 1348, and is configured to be communicatively coupled to the controller 1305 at the control connection terminal.

[0093] The fifth diode 1328 includes: a cathode connection terminal coupled to the first inductor 1322, the first switching device 1326, and the eighth diode 1346; and an anode connection terminal coupled to the sixth diode 1330 and the reference node 1313. The sixth diode 1330 includes: a cathode connection terminal coupled to the fifth diode 1328 and the reference node 1313, and an anode connection terminal coupled to the second inductor 1324, the first switching device 1326, and the ninth diode 1348.

[0094] The second relay 1334 is configured as a single-pole single-throw switching device having a first terminal, a second terminal, and a third terminal. The third terminal is configured to be switchably connected to one of the first and second terminals. The first terminal is configured to be coupled to a seventh diode 1336, a third inductor 1338, and a fourth inductor 1340. In one embodiment, the second terminal may not be permanently connected to any other component and is configured to be switchably connected to the third terminal. Therefore, in one embodiment, current does not flow through the second terminal. The third terminal is configured to be coupled to an energy storage device 1332 and the seventh diode 1336.

[0095] The seventh diode 1336 includes: an anode connection configured to be coupled to a third terminal of the second relay 1334; and a cathode connection configured to be coupled to a first terminal of the second relay 1334. A third inductor 1338 is coupled to the first terminal of the second relay 1334 at the first connection and to a second switching device 1342 at the second connection. The third inductor 1338 is also configured to be magnetically coupled to a first inductor 1322. A second inductor 1340 is coupled to the first terminal of the second relay 1334 at the first connection and to the third switching device 1344 at the second connection. A fourth inductor 1340 is also configured to be magnetically coupled to the second inductor 1324.

[0096] The second switching device 1342 is configured to couple to the third inductor 1338 at a first connection terminal, to the energy storage device 1332 at a second connection terminal, and communicatively coupled to the controller 1305 at a control connection terminal. The third switching device 1344 is configured to couple to the fourth inductor 1340 at a first connection terminal, to the energy storage device 1332 at a second connection terminal, and communicatively coupled to the controller 1305 at a control connection terminal. The energy storage device 1332 is coupled to the third terminal of the second relay 1334 at the first connection terminal, and to both the third inductor 1342 and the fourth inductor 1344 at the second connection terminal.

[0097] As described above, the main branch 1308 is similar to the standby branch 208 and includes a third diode 1318 and a fourth diode 1320. The third diode 1318 and the fourth diode 1320 provide a walk-in power input. This walk-in power input can be advantageous when the UPS 1300 transitions from standby operation mode to normal operation mode. After transitioning from standby to normal operation mode, the UPS 1300 can resume drawing power from the AC input terminal 1306. The UPS 1300 can draw a significant amount of current from the AC input terminal 1306 when connected to it. The walk-in power input refers to a feature of the UPS 1306 where the current drawn from the AC input terminal 1306 gradually increases when transitioning from standby to normal operation mode.

[0098] As described above, the third diode 1318 and the fourth diode 1320 are connected to the reference node 1313. The third diode 1318 and the fourth diode 1320 provide power input by coupling components of the UPS 1300 (e.g., including at least one of the first diode 1314, the second diode 1316, the first inductor 1322, and the second inductor 1324) to the reference node 1313 during the transition of the UPS 1300 from standby operation mode to normal operation mode. Because components are coupled to the reference node 1313 during the transition, the amount of current drawn by the UPS 1300 from the AC power supply 1306 is reduced when the transition from standby operation mode to normal operation mode is completed.

[0099] As described above, the backup branch 1310 is similar to the backup branch 210 and further includes a seventh diode 1336 having: a cathode connection coupled to a first terminal of the second relay 1334, which is coupled to a third inductor 1338 and a fourth inductor 1340; and an anode connection coupled to a third terminal of the second relay 1334, which is coupled to an energy storage device 1332. The seventh diode 1336 enables a faster transition from normal operating mode to backup operating mode.

[0100] For example, in one embodiment, the UPS 1300 can transition from a normal operating mode to a standby operating mode. Therefore, the controller 1305 can control the second relay 1334 to transition from connecting the third terminal to the second terminal (which may be the configuration of the second relay 1334 during normal operating mode) to connecting the third terminal to the first terminal (which may be the configuration of the second relay 1334 during standby operating mode). Before the second relay 1334 completes the transition, current from the energy storage device 1332 may not be able to flow from the third terminal of the second relay 1334 to the first terminal of the second relay 1334 because the conductive path through the second relay 1334 has not yet been completed.

[0101] In one example, a seventh diode 1336 connected in parallel with the second relay 1334 enables the energy storage device 1332 to discharge through a conductive path including: the energy storage device 1332; the seventh diode 1336; and at least one of the third inductor 1338 and the second switching device 1342, or the fourth inductor 1340 and the third switching device 1344, while the second relay 1334 completes the transition from connecting the third terminal to the second terminal to connecting the third terminal to the first terminal. In other words, because the seventh diode 1336 is connected in parallel with the second relay 1334, the energy storage device 1332 is allowed to discharge through the seventh diode 1336 before the second relay 1334 fully transitions from a normal operating mode configuration to a standby operating mode configuration. Therefore, the seventh diode 1336 enables the energy storage device 1332 to quickly begin discharging during the transition from normal operating mode to standby operating mode.

[0102] Figure 14 A schematic diagram of a UPS 1400 according to an embodiment is shown. The UPS 1400 includes a dual converter 1402, an inverter 1404, and a controller 1405. The dual converter 1402 is configured to be coupled to an AC input 1406 and to the inverter 1404. The inverter 1404 is coupled to the dual converter 1402 and configured to be coupled to a load 1408.

[0103] UPS 1400 is similar to UPS 200. For example, the dual converter 1402, inverter 1404, and controller 1405 are similar to dual converter 202, inverter 204, and controller 205. UPS 1400 also includes a relay 1410 configured as a single-pole double-throw switching device with a first terminal, a second terminal, and a third terminal. The third terminal is configured to be switchably connected to one of the first and second terminals. The first terminal is configured to be coupled to AC input 1406. The second terminal is coupled to inverter 1404. The third terminal is configured to be coupled to load 1408.

[0104] Relay 1410 is configured to operate in a bypass mode in addition to standby and normal operating modes. In bypass mode, the third terminal of relay 1410 is coupled to the first terminal, allowing AC power supplied by AC input 1406 to bypass the dual converter 1402 and inverter 1404. In normal or standby mode, the third terminal of relay 1410 is coupled to the second terminal, allowing AC input 1406 to supply input power to the dual converter 1402, thus enabling UPS 1400 to operate similarly to UPS 200.

[0105] Controller 1405 may provide one or more control signals to relay 1410 to control the switching position of relay 1410. For example, controller 1405 may select a bypass operation mode, thereby controlling relay 1410 to connect its third terminal to its first terminal in response to determining that the AC power supplied by AC input 1406 is of sufficiently high quality. Determining that the AC power quality is sufficiently high may include determining that parameters of the AC power are within a threshold range.

[0106] For example, controller 1405 can determine that the AC power voltage is within 1V of an ideal 120V sinusoidal waveform, and therefore the AC power has sufficiently high quality to be directly supplied to load 1408. Otherwise, continuing the previous example, if the AC power voltage is not within 1V of an ideal 120V sinusoidal waveform, controller 1405 can determine that the AC power should be processed by dual converter 1402 and inverter 1404 before being supplied to load 1408. Therefore, controller 1405 can control relay 1410 to connect the third terminal of relay 1410 to the second terminal and select either a standby operating mode or a normal operating mode.

[0107] As described above, the UPS disclosed herein can be controlled by multiple controllers, including controller 205, controller 1205, controller 1305, and controller 1405. Using data stored in associated memory, the controller can execute one or more instructions stored on one or more non-transitory computer-readable media, which may result in data manipulation. In some examples, the controller may include one or more processors or other types of controllers. In another example, the controller includes a Field-Programmable Gate Array (FPGA) controller.

[0108] In yet another example, the controller performs one part of the functions disclosed herein on the processor and another part using an application-specific integrated circuit (ASIC) adapted to perform a particular operation. As these examples illustrate, examples according to the invention can use many specific combinations of hardware and software to perform the operations described herein, and the invention is not limited to any particular combination of hardware and software components.

[0109] As described above, the UPS 200 can receive power from the energy storage device 228, which can be internal, external, or coupled to the UPS 200. In some embodiments, the energy storage device 228 can be coupled to an external charging device (not shown) configured to charge the energy storage device 228 with electrical energy. In an alternative embodiment, the dual converter 202 can be configured to charge the energy storage device 228 from energy derived from the AC power supply 206.

[0110] For example, recharging the energy storage device 228 may include controlling a second relay 230; and at least one of a second switching device 236 and a third switching device 238 to provide a conductive path including: the energy storage device 228; the second relay 230; and either one or both of the third inductor 232 and the second switching device 236, and the fourth inductor 234 and the third switching device 238. At least a portion of the power supplied by the AC power source 206 may be supplied to the energy storage device 228 through at least one of the first inductor 218 and the third inductor 232, the second inductor 220, and the fourth inductor 234 to charge the energy storage device 228.

[0111] In one example, charging the energy storage device 228 may include: controlling a second relay 230 to connect a third terminal of the second relay 230 to a first terminal of the second relay 230; and controlling a second switching device 236 to be in a closed and on position during the positive half-cycle of the AC power supplied by the AC power source 206. The first inductor 218 can be energized during the positive half-cycle of the AC power supplied by the AC power source 206, and the magnetically coupled third inductor 232 can also be energized. The third inductor 232 can discharge an induced current into the energy storage device 228 through a conductive path including the energy storage device 228, the second relay 230, the third inductor 232, and the second switching device 236, thereby charging the energy storage device 228.

[0112] In another example, charging the energy storage device 228 may include: controlling the second relay 230 to connect its third terminal to its first terminal; and controlling the third switch 238 to be in a closed and on position during the negative half-cycle of the AC power supplied by the AC power source 206. The second inductor 220 may be energized during the negative half-cycle of the AC power supplied by the AC power source 206, and this energizes the magnetically coupled fourth inductor 234. The fourth inductor 234 may discharge an induced current into the energy storage device 228 through a conductive path including the energy storage device 228, the second relay 230, the fourth inductor 234, and the third switch 238, thereby charging the energy storage device 228.

[0113] Based on the preceding comments, this paper has described a UPS with reduced size and component count, and increased flexibility. In one example, a UPS with dual converters has been described. This dual converter includes components configured to operate in both standby and normal operating modes, whereas some conventional UPSs include a first set of components operating in standby mode and a second set operating in normal operating mode. Furthermore, the dual converter is configured to control the amount of power supplied to each individual DC bus capacitor, whereas some conventional UPSs are only able to supply equal amounts of power to each DC bus capacitor. Therefore, the number of components can be reduced, thereby lowering the cost and physical size of the UPS while increasing its flexibility.

[0114] While some embodiments have shown dual converters implemented with a UPS, other exemplary converters can be implemented without a UPS. Dual converters can be implemented in any other environment or topology and are not limited to examples including a UPS. For example, dual converters can be implemented using power devices other than a UPS.

[0115] Therefore, several aspects of at least one embodiment of the invention have been described, and various changes, modifications, and improvements will readily occur to those skilled in the art. Such changes, modifications, and improvements are intended as part of this disclosure and are intended to fall within the spirit and scope of the invention. Therefore, the foregoing description and drawings are merely illustrative.

Claims

1. An uninterruptible power supply (UPS) system, characterized in that, The UPS system includes: A first input terminal is configured to be coupled to an input power supply; A second input terminal is configured to be coupled to an energy storage device; One output terminal, configured to provide output power; A power conversion circuit configured to convert power received from at least one of the input power source or the energy storage device, the power conversion circuit comprising: A main branch, having a first inductor and a third inductor; and A backup branch section has a second inductor and a fourth inductor, the second inductor being magnetically coupled to the first inductor, the fourth inductor being magnetically coupled to the third inductor, and the main branch section being electrically isolated from the backup branch section; An output circuit, coupled to the power conversion circuit and coupled to the output terminal; and A controller, coupled to the power conversion circuit and the output circuit, and configured to: Control the power conversion circuit to supply direct current (DC) power from the input power source to the output circuit via the first inductor and the third inductor in a normal operating mode; and The power conversion circuit is independently controlled to supply DC power from the energy storage device to the output circuit via the first inductor and the second inductor, as well as via the third inductor and the fourth inductor, in a standby operating mode.

2. The uninterruptible power supply system as described in claim 1, characterized in that: The output circuit includes: a first capacitor configured to be coupled to the power conversion circuit; and a second capacitor configured to be coupled to the power conversion circuit.

3. The uninterruptible power supply system as described in claim 1, characterized in that: The second inductor is coupled to a first switching device, and the fourth inductor is coupled to a second switching device.

4. The uninterruptible power supply system as described in claim 3, characterized in that: The controller is further configured to control the first switching device to charge a first capacitor, and configured to control the second switching device to charge a second capacitor.

5. The uninterruptible power supply system as described in claim 4, characterized in that: The controller is further configured to control the first switching device to charge the first capacitor at a first rate, and configured to control the second switching device to charge the second capacitor at a second rate different from the first rate.

6. The uninterruptible power supply system as described in claim 4, characterized in that: The controller is also configured to control the first switching device and the second switching device to simultaneously charge the first capacitor and the second capacitor.

7. The uninterruptible power supply system as described in claim 4, characterized in that: Controlling the first switching device to charge the first capacitor includes: Controlling the first switching device to enable the energy storage device to supply current to the second inductor, wherein supplying current to the second inductor includes: inducing a voltage across the first inductor; and Control the first switching device to prevent the energy storage device from supplying current to the second inductor. The first inductor is configured to discharge to the first capacitor in response to the first switching device disabling the energy storage device.

8. The uninterruptible power supply system as described in claim 7, characterized in that: Controlling the second switching device to charge the second capacitor includes: Controlling the second switching device to enable the energy storage device to supply current to the fourth inductor, wherein supplying current to the fourth inductor includes: inducing a voltage across the third inductor; and Control the second switching device to prevent the energy storage device from supplying current to the fourth inductor. The third inductor is configured to discharge to the second capacitor in response to the second switching device disabling the energy storage device.

9. The uninterruptible power supply system as described in claim 1, characterized in that: The backup branch section also includes: A switching device having: a first connection terminal coupled to the energy storage device; and a second connection terminal switchably coupled to the second inductor; and A diode has: an anode connection terminal coupled to a first connection terminal of the switching device; and a cathode connection terminal coupled to a second connection terminal of the switching device.

10. The uninterruptible power supply system as described in claim 1, characterized in that: Also includes: A switching device, the switching device comprising: A first connection terminal, coupled to the output terminal; and A second connection terminal is configured to be coupled to either the output circuit or the first input terminal. The controller is configured to: control the switching device in a bypass operation mode to connect the second connection terminal to the first input terminal; and is configured to control the switching device in the normal operation mode and the standby operation mode to connect the second connection terminal to the output circuit.

11. The uninterruptible power supply system as described in claim 1, characterized in that: Also includes: A first diode having: a cathode connection terminal coupled to the first inductor; And the anode connection coupled to a reference node; and A second diode has: a cathode connection coupled to the reference node; and an anode connection coupled to the third inductor.

12. An uninterruptible power supply (UPS) system, characterized in that, The UPS system includes: A first input terminal is configured to be coupled to an input power supply; A second input terminal is configured to be coupled to an energy storage device; An output terminal is configured to provide output power from at least one of the first input terminal or the second input terminal; An output circuit, coupled to the output terminal, the output circuit comprising: a positive DC bus and a negative DC bus; and A plurality of devices for independently supplying power from at least one of the first input terminal or the second input terminal to the positive DC bus and the negative DC bus includes a power conversion circuit comprising a main branch portion and a backup branch portion, the main branch portion being magnetically coupled to the backup branch portion and electrically isolated from the backup branch portion, wherein the main branch portion has a first inductor and a third inductor, and the backup branch portion has a second inductor and a fourth inductor, the second inductor being magnetically coupled to the first inductor and the fourth inductor being magnetically coupled to the third inductor.

13. The uninterruptible power supply system as described in claim 12, characterized in that: The output circuit includes a first capacitor and a second capacitor.

14. The uninterruptible power supply system as described in claim 13, characterized in that: Also includes: Multiple means for charging the first capacitor at a first rate; And a plurality of means for charging the second capacitor at a second rate different from the first rate.

15. The uninterruptible power supply system as described in claim 13, characterized in that: Also includes: Multiple devices for simultaneously charging the first capacitor and the second capacitor.

16. A non-transitory computer-readable medium, characterized in that: The non-transitory computer-readable medium stores a sequence of computer-executable instructions for controlling an electrical device, the electrical device comprising: a first input terminal for receiving a first input power; a second input terminal for receiving a second input power; an output terminal for providing output power; an output circuit for providing the output power to the output terminal; and a power conversion circuit comprising: a main branch having a first inductor and a third inductor; and a spare branch having a second inductor and a fourth inductor, the second inductor being magnetically coupled to the first inductor, the fourth inductor being magnetically coupled to the third inductor, the main branch being electrically isolated from the spare branch, wherein the sequence of computer-executable instructions comprises a plurality of instructions instructing at least one processor to independently control one or more switching devices in the electrical device to: The first input power is received through the first inductor and the third inductor in a normal operating mode; In the normal operating mode, the first power sourced from the first input power is supplied to the output circuit through the first inductor and the third inductor. The second input power is received through the second inductor and the fourth inductor in a standby operating mode; The second inductor stores the first stored energy derived from the second input power in the standby operation mode; The third stored energy originating from the second input power is stored in the standby operation mode through the fourth inductor; The first inductor stores second stored energy derived from the first stored energy in the standby operation mode; The third inductor stores fourth energy derived from the third stored energy in the standby operation mode; In the standby operation mode, the first inductor supplies second power derived from the second stored energy to the output circuit; and In the standby operating mode, the third inductor supplies a fourth power source derived from the fourth stored energy to the output circuit.

17. The non-transitory computer-readable medium as claimed in claim 16, characterized in that: The output circuit includes a first capacitor and a second capacitor; the computer-executable instruction sequence further includes a plurality of instructions instructing the at least one processor to control the one or more switching devices to provide a first charging current to the first capacitor and a second charging current to the second capacitor, wherein the first charging current is provided at a first rate and the second charging current is provided at a second rate, the first rate being different from the second rate, and wherein the first charging current and the second charging current are provided simultaneously.

18. The non-transitory computer-readable medium as claimed in claim 16, characterized in that: The power equipment further includes a switching device having: a first connection terminal coupled to the output terminal; and a second connection terminal configured to be coupled to one of the output circuit or the first input terminal, wherein the computer-executable instruction sequence further includes a plurality of instructions instructing the at least one processor to: control the switching device to connect the second connection terminal to the first input terminal in a bypass operation mode; and control the switching device to connect the second connection terminal to the output circuit in the normal operation mode and the standby operation mode.

19. A control method for electrical equipment, characterized in that: The power equipment includes a first input terminal for receiving first input power, a second input terminal for receiving second input power, an output terminal for providing output power, an output circuit for providing the output power to the output terminal, and a power conversion circuit. The power conversion circuit includes a main branch having a first inductor and a third inductor, and a spare branch having a second inductor and a fourth inductor. The second inductor is magnetically coupled to the first inductor, and the fourth inductor is magnetically coupled to the third inductor. The main branch is electrically isolated from the spare branch. The method includes: The first input power is received through the first inductor and the third inductor in a normal operating mode; In the normal operating mode, the first power sourced from the first input power is supplied to the output circuit through the first inductor and the third inductor. The second input power is received through the second inductor and the fourth inductor in a standby operating mode; The second inductor stores the first stored energy derived from the second input power in the standby operation mode; The third stored energy originating from the second input power is stored in the standby operation mode through the fourth inductor; The first inductor stores second stored energy derived from the first stored energy in the standby operation mode; The third inductor stores fourth energy derived from the third stored energy in the standby operation mode; In the standby operation mode, the first inductor supplies second power derived from the second stored energy to the output circuit; and In the standby operating mode, the third inductor supplies a fourth power source derived from the fourth stored energy to the output circuit.

Images