Persistent dc circuit breaker

Abstract

The present invention relates to a persistent DC circuit breaker. A persistent DC circuit breaker provides persistent single or dual DC voltage to a power distribution circuit coupled to a power distribution panel. Control mechanisms ensure constant and consistent DC power output from the persistent DC circuit breaker. The persistent DC circuit breaker can replace an AC circuit breaker, convert an AC power panel to a coexisting AC and DC power panel or an entire DC power panel.

Description

Technical Field

[0001] The present invention relates to an apparatus and method for the co-distribution of AC (Alternating Current) and DC (Direct Current) power, and more particularly, to a power board configured with a persistent DC circuit breaker to replace an AC circuit breaker to facilitate the coexistence of AC and persistent DC. Background Technology

[0002] An AC power board connected to AC power includes multiple AC circuit breakers to drive the AC distribution circuit. A drawback of existing systems is that almost all electronic devices contain integrated circuits that operate on DC power, which cannot be directly obtained from the AC distribution circuit. Therefore, a power adapter is needed to convert AC power to DC. It would be highly useful to have DC power directly available from the distribution circuit, allowing electronic devices (e.g., mobile phones or laptops) to access DC power directly without a power adapter. Power boards that can provide DC power for electronic devices and AC power to meet the needs of traditional AC equipment in the physical infrastructure are desirable. Summary of the Invention

[0003] A significant number of electronic devices or equipment still operate on AC power. Therefore, a universal power distribution system must not only deliver DC power to DC distribution circuits for solid-state electronic devices, but also provide AC power to AC distribution circuits to meet the needs of traditional AC devices in the home. Embodiments of this disclosure provide this universal power in a coexisting AC and DC system.

[0004] Electronic devices can operate under different power supply voltages. Therefore, according to embodiments of this disclosure, the DC power distribution system advantageously supplies different DC voltages to different DC power distribution circuits for different electronic devices requiring different DC voltages. To achieve this, according to embodiments of this disclosure, a permanent DC circuit breaker is incorporated into the power board, wherein the AC circuit breaker in the power board can be replaced by the permanent DC circuit breaker, which also converts the AC power distribution circuit into a DC power distribution circuit to provide the required DC voltage. Replacing the circuit breaker is cost-effective and highly flexible in distributing DC power. It also allows the AC power system to be converted into a coexisting AC and DC power supply system, or a DC-only supply system.

[0005] One requirement for DC power distribution circuits is that DC power must be constant and continuously available regardless of the availability of external DC power. In other words, DC power is ideally continuous power.

[0006] There are two technologies for ensuring a continuous DC power supply. The first technology is to use a centralized AC-to-DC converter (ADC) on the power board to generate DC power to output to the entire DC distribution circuit. The centralized ADC is activated when external or regenerated DC energy becomes unavailable.

[0007] The second technique is a distributed approach, where a persistent DC circuit breaker is used instead of an AC circuit breaker by incorporating an AC-to-DC power converter in parallel with the circuit breaker. Similarly, the ADC in the persistent DC circuit breaker is activated only when an external DC power supply is unavailable. The persistent DC circuit breaker persistently uses AC power to perform DC conversion to output DC power.

[0008] A centralized ADC limits the amount of DC power that can be supplied from the power board to drive all the DC distribution circuits connected to the power board. Therefore, additional DC-DC converters are needed to connect to the DC distribution circuits to increase or decrease the DC voltage.

[0009] The second technology is more flexible than the first. Converting an AC distribution circuit to a DC distribution circuit is also straightforward by replacing the AC circuit breaker with a permanent DC circuit breaker in the power board. The same electrical interconnects in the building can be used as either AC or DC distribution circuits, depending on whether an AC or DC circuit breaker is selected in the power board to drive the distribution interconnects.

[0010] Furthermore, up to two different DC voltages can be supplied on the same electrical interconnect supplying 120V AC power, or up to three different DC voltages on the same electrical interconnect supplying 240V AC power. The neutral wire, which carries the return current to the AC distribution circuit, can be used to carry an additional DC voltage different from the DC voltage on the lines used for the AC phase wires. The ground wire, which does not carry AC current in the AC distribution circuit, can be used as a DC current return path and can carry the highest DC current in the DC distribution circuit. Attached Figure Description

[0011] Figure 1 An exemplary AC and permanent DC coexistence power board is shown, incorporating AC and permanent DC circuit breakers.

[0012] Figure 2 An exemplary functional block diagram of a persistent single DC circuit breaker with protection against power distribution circuit anomalies is shown.

[0013] Figure 3 An exemplary functional block diagram of a persistent dual DC circuit breaker with fault protection features is shown. Detailed Implementation

[0014] According to embodiments of this disclosure, DC power is directly supplied to electronic devices, such as mobile phones or laptops, on a distribution circuit. To achieve this, according to one embodiment, a power board provides DC power to the electronic devices while also providing AC power to meet the needs of conventional AC devices in the physical infrastructure. Therefore, embodiments of this disclosure eliminate the need for power adapters while supporting existing conventional AC devices in the building for efficient use of renewable energy.

[0015] Coexisting AC and permanent DC power boards provide both AC and DC power in a building. An AC power board can be converted to an AC / DC coexisting power board by replacing its AC circuit breaker with a permanent DC circuit breaker. Figure 1 An exemplary configuration of this power panel 100 is shown. A DC input from an external DC power source 115 is connected to the panel. The external DC power 115 (e.g., energy regenerated by a solar panel or stored in a battery pack) can be regulated by a voltage regulator 116 before being applied to the power panel 100. The DC power input to the power panel 100 can be manually turned off by a DC main switch 125.

[0016] There is also an AC main switch 120, used to control the AC power input to the AC circuit breakers and DC circuit breakers in the power board 100. AC power is the primary power used for the AC circuit breakers. However, AC power is auxiliary power used for the permanent DC circuit breakers. In the United States, AC power input typically includes two phase wires and a neutral wire, where the phase and neutral wires provide 120V AC power. Two phase wires provide 240V AC power to meet higher power requirements.

[0017] exist Figure 1 In the exemplary embodiment shown, AC circuit breaker 131 distributes AC power to AC power distribution circuit 141. A persistent single DC circuit breaker 132 distributes a single DC voltage to DC distribution circuit 142, and persistent dual DC circuit breakers 138 and 139 distribute two DC voltages to DC distribution circuits 148 and 149. The voltages on the two DC distribution circuits 148 and 149 may be different.

[0018] The interchangeability of AC circuit breakers and permanent DC circuit breakers allows for conversion between AC and DC power distribution circuits. AC power, single DC power, or dual DC power can be distributed to the power distribution circuit by correctly selecting or replacing the circuit breaker in the circuit breaker slot on the power board. Configuring power output in coexisting AC and permanent DC power systems is flexible and cost-effective. Permanent DC circuit breakers can also be programmed to output different DC voltages for use.

[0019] In AC circuit breakers, the ground wire is not connected, and in DC circuit breakers, the ground wire is also not connected. For safety reasons, the ground wire is connected to the AC outlet. However, the ground wire is also connected to the outlet on the DC distribution circuit to provide a ground voltage reference for DC devices plugged into the outlet and to provide a current return path to the DC distribution circuit.

[0020] Figure 2 An exemplary functional block diagram of a persistent single DC circuit breaker is shown. A persistent DC circuit breaker refers to a circuit breaker that provides uninterrupted availability of a substantially constant and consistent DC voltage, regardless of the availability of external regenerated DC power.

[0021] AC power switch 211 and DC power switch 212 include Figure 2 The permanent DC circuit breaker 200 shown in the diagram. Both the AC power switch 211 and the DC power switch 212 can be manually controlled to connect their respective AC and DC power inputs to the circuit breaker 200. Figure 2 Even if AC switch 211 is manually closed, the persistent DC circuit breaker 200 can still output DC power as long as external DC power is available. When DC switch 212 is manually closed or there is no connection to external DC power, the persistent DC circuit breaker 200 can still continuously provide DC power if AC power is supplied to its embedded ADC 235. The persistent DC circuit breaker will only stop outputting DC power when both AC switch 211 and DC switch 212 are manually closed. The persistent DC circuit breaker 200 includes a persistent DC power module 205, and the control circuitry enables the persistent DC circuit breaker 200 to provide persistent DC power.

[0022] exist Figure 2 In this circuit, an external DC input 215 is supplied to the persistent single DC power module 205 via a DC power switch 212. The external DC input 215 is regulated by a DC regulator 225 to the voltage required by the DC power distribution circuit connected to the circuit breaker 200.

[0023] An automatic AC switch 220 is present in the persistent DC power module 205, which can be automatically switched on or off under the control of a voltage monitoring device (i.e., an AC switching control comparator 230) to initiate AC input 210 to the DC power module as needed. The AC switching control comparator monitors the availability and strength of external DC power by comparing its attenuated input with a reference voltage (e.g., reference voltage Vrefa). A voltage divider can be applied to attenuate the DC input 215 to a voltage level compatible with the device supply voltage VCC. VCC can be derived from a rechargeable battery, or generated using a DC-DC regulator of DC power 215, or using an AC-DC regulator with AC power as input, or even using an external VCC input to a circuit breaker.

[0024] If the attenuated DC input is higher than Vrefa, comparator 230 will output a high level. The output of inverter 231 will remain low without affecting the normally open (NO) AC automatic switch 220, which will continue to remain in its default normally open (NO) state. The output of AC manual switch 211 can be added to the output of inverter 231 to control the switching of AC automatic switch 220. Furthermore, AC manual switch 211 can be connected in series with AC automatic switch 220 at the phase line.

[0025] When the external DC input 215 decreases and its attenuation drops below Vrefa, the AC switching control comparator will change its output to a low level. This change to a high level at the inverter 231 output will close the normally open AC automatic switch 220, allowing the AC input 210 to power the embedded ADC 235. The AC automatic switch 220 can be a solid-state relay (SSR) or an electromagnetic relay (EMR) that uses a double-pole or MOSFET to control its switching.

[0026] The output of ADC 235 is also regulated to voltage in the same manner as the regulated output of DC regulator 225 to ensure a constant DC voltage is available from the persistent DC circuit breaker 200. The reference voltage Vrefr is used as the control voltage to ensure the same regulated output voltage from the regulators in both DC regulator 225 and ADC 235.

[0027] Another voltage sensing device 232 (e.g., an output switch-controlled comparator) compares the attenuated DC voltage from DC input 215 with a reference voltage Vrefo. When the attenuated DC input is lower than Vrefo, the output switch-controlled comparator 232 changes from high to low. The output of inverter 233 thus changes from low to high, causing the regulated ADC output to be sent to DC output port 250 as normally open (NO) DC switch 241 closes; simultaneously, the output of comparator 232 causes normally open DC switch 240 to return to open, disconnecting the output of DC regulator 225 to DC output port 250.

[0028] DC switches 240 and 241 can be load switches that include MOSFET devices to control the DC switch. Solid-state DC switches can be implemented as normally open if an enhancement-mode MOSFET is used in its pass gate. Alternatively, a depletion-mode MOSFET can be implemented as normally closed if a depletion-mode MOSFET is used in its pass gate. Positive logic is used throughout the description for clarity. SSRs or EMRs can also be used as DC switches.

[0029] This pair of DC switches 240, 241 is used to select the regulated DC voltage from the external DC input 215, or to select the voltage converted by the ADC 235 for output to the persistent DC circuit breaker 200. This pair of switches can be replaced by a DC multiplexer (or a DC multiplexer (DC mux)), wherein when the output switch controls the comparator 232 to output a high level, the output of the DC regulator 225 is sent to the output of the DC multiplexer, and when the output switch controls the comparator 232 to output a low level, the regulated output of the ADC 235 is sent to the output of the DC multiplexer.

[0030] The voltage level of Vrefo is lower than the voltage level of Vrefa. This ensures that the AC automatic switch 220 opens in advance to power the ADC 235 when the external DC input 215 begins to decrease. However, Vrefo is higher than Vrefr. This ensures that the DC regulator 225 is pre-charged by the external DC input 215 before the pair of DC switches 240, 241 change states, so that the regulated output from the DC regulator 225 can be supplied at the output of the persistent DC circuit breaker 200. Therefore, persistent DC power is always supplied from the persistent DC circuit breaker 200 at the same constant DC voltage.

[0031] The reference voltages Vrefa, Vrefo, and Vrefr are programmable to meet reference voltage requirements. Alternatively, a single reference voltage, the highest reference voltage Vrefa, can be selected for the persistent DC power module 205, then stepped down to Vrefo, and further stepped down to Vrefr to maintain a fixed voltage difference between the set of reference voltages. Vrefa can also be a predetermined fixed value programmable in the DC circuit breaker 200 when the voltage output from the DC circuit breaker 200 is known.

[0032] If any power distribution circuit malfunctions (e.g., short circuit, arcing, overvoltage, or overheating), the circuit breaker will disconnect its power output. To achieve this, the DC fault protection logic 245 implemented in the persistent DC power module 205 includes a fault detection or fault protection circuit 246 that monitors the output of the DC circuit breaker 200 to detect any circuit malfunctions in the DC power distribution circuit it drives. In the event of any malfunction in the power distribution circuit, the inverted output of the inverter 247 connected to the fault protection circuit 246 will open two DC circuit switches 240 and 241.

[0033] In the event of any circuit malfunction in the DC power distribution circuit connected to circuit breaker 200, the output of the DC power multiplexer (if used to replace this pair of DC switches 240, 241) will also be disconnected from the output of DC circuit breaker 200.

[0034] The persistent single DC power module 205, which includes control circuitry that facilitates input DC power detection, power regulation, power conversion, and circuit fault protection, can be implemented or manufactured in a multi-chip package (MCP) or included as one or more integrated circuits in a DC circuit breaker that requires a compact physical size.

[0035] Figure 3 An exemplary functional block diagram of a persistent dual DC circuit breaker 300 according to one embodiment of the present disclosure is shown. A persistent dual DC power module 305 is included in this circuit breaker 300 as a main control circuit. Figure 2 As shown, a persistent dual DC power module can be implemented by combining two persistent single DC power modules together. Similarly, it can be implemented as an MCP or fabricated as one or more integrated circuits to provide dual DC power.

[0036] As described above, the AC distribution circuit can be used as a dual DC power delivery system. A double-pole single-throw (DPST) manual switch 311 can be selected to disconnect a pair of phase lines from the AC input 310 in the persistent dual DC circuit breaker 300. Alternatively, two separate SPST switches can be selected to disconnect both phase lines in the AC input 310 of the persistent dual DC circuit breaker 300, where each SPST switch controls a 120V AC power input to a corresponding ADC 335 or 336. Alternatively, both phase lines can be supplied to a single ADC to generate two regulated DC voltages.

[0037] By incorporating a centralized ADC into the power board, all circuit breakers connected to the power board primarily function as mechanical switches. This differs from the embodiments of this disclosure, which have an ADC embedded in each DC circuit breaker that operates as an active DC circuit breaker with corresponding automatic control functions.

[0038] ADCs increase the flexibility in configuring DC power boards, providing the required DC power to their respective DC distribution circuits. Distributed DC circuit breakers offer even greater flexibility in providing different DC output voltages for use.

[0039] Persistent DC circuit breakers can have more flexibility to have different output voltages if their regulator control reference voltage Vrefr is adjustable or programmable.

[0040] Using removable persistent DC circuit breakers, existing AC power boards can be configured as AC power boards, coexisting AC and DC power boards, or persistent DC power boards by replacing circuit breakers in the power board. External DC power needs to be input to the persistent DC power board, regardless of whether the approach is centralized or distributed. In a distributed approach, each persistent DC circuit breaker requires an additional DC connection on each circuit breaker. Suitable connectors are included in the persistent DC power board to accept external DC power, thereby receiving the DC power input from the circuit breaker.

Claims

1. A device suitable for providing continuous DC power, the device comprising: AC power input port, which is coupled to an AC power supply via an AC manual switch; A DC input port is coupled to an external DC power source via a DC manual switch; DC output port; as well as A persistent DC power module coupled to the DC output port, the persistent DC power module comprising: A DC voltage regulator wherein the external DC power received from the DC input port is regulated according to a first reference voltage to generate a regulated DC voltage; An AC-to-DC converter, i.e., an ADC, is adapted to convert the AC power supply received from the AC power input port into a converted DC voltage based on a first reference voltage; and The control circuit includes a first comparator adapted to compare the external DC power with a second reference voltage, wherein the second reference voltage is higher than the first reference voltage, and wherein the first comparator outputs a logic high level when the external DC voltage is higher than the second reference voltage. When the first comparator output is at the logic high level, the control circuit is adapted to allow the regulated DC voltage to be delivered to the DC output port, and When the output of the first comparator is not at the logic high level, the control circuit is adapted to enable the converted DC voltage to be delivered to the DC output port; and The AC power input port is also coupled to an AC automatic switch controlled by a second comparator, the second comparator being adapted to compare the external DC voltage with a third reference voltage, wherein the third reference voltage is higher than the second reference voltage, and wherein the second comparator is adapted to: When the output of the second comparator is at a logic low level, the AC power supply supplies power to the ADC, and When the output of the second comparator is at a logic high level, the AC power supply to the ADC is disabled.

2. The apparatus according to claim 1, wherein, The control circuit also includes First DC switch and second DC switch; wherein When the output of the first comparator is at the logic high level, the first DC switch connects the regulated DC voltage to the DC output port, and the second DC switch disconnects the converted DC voltage from the DC output port. When the output of the first comparator is not at the logic high level, the first DC switch disconnects the regulated DC voltage from the DC output port, and the second DC switch connects the converted DC voltage to the DC output port.

3. The apparatus according to claim 1, wherein, When the output of the first comparator is at a logic high level, the regulated DC voltage is delivered to the DC output port, and When the output of the first comparator is at a logic low level, the converted DC voltage is delivered to the DC output port.

4. The apparatus according to claim 1, wherein, The first reference voltage is programmable to regulate the output voltage of the persistent DC power module.

5. The apparatus according to claim 1, wherein, The third reference voltage is higher than the second reference voltage, and the second reference voltage is higher than the first reference voltage.

6. The apparatus according to claim 1, wherein, The first reference voltage and the second reference voltage are generated by the third reference voltage and are less than the third reference voltage.

7. The apparatus according to claim 1, wherein, The persistent DC power module is formed in one or more integrated circuits.

8. The apparatus according to claim 1, wherein, The persistent DC power module is formed in a multi-chip module (MCP).

9. The apparatus according to claim 1, wherein, The persistent DC power module is assembled with a set of discrete devices.

10. The apparatus according to claim 1, wherein, The AC manual switch and the AC automatic switch are connected in series to the phase line input of the AC power supply.

11. The apparatus according to claim 1, wherein, The AC automatic switch is selected by the output of the AC manual switch to disable the AC automatic switch.

12. The apparatus of claim 3, further comprising a fault protection circuit in the persistent DC power module for monitoring anomalies on the power distribution circuit connected to the DC output port, and disabling the supply of the regulated DC voltage and the converted DC voltage to the DC output port when a circuit anomaly occurs.

13. The apparatus of claim 2 further includes a fault protection circuit in the persistent DC power module to monitor for anomalies on the power distribution circuit connected to the DC output port, and to disconnect the output of the first and second DC switches to the DC output port when a circuit anomaly occurs.

14. The apparatus according to claim 13, wherein, The fault protection circuit detects circuit abnormalities such as short circuits, arcing, overvoltage, and overheating to protect devices connected to the DC output port from damage.

15. The apparatus of claim 13, wherein the apparatus forms a persistent single DC circuit breaker to distribute single DC power to a distribution circuit connected to the apparatus.

16. The apparatus according to claim 1, further comprising: A second persistent DC power module is coupled to a second DC output port, the second persistent DC power module comprising: The second DC voltage regulator, wherein the external DC power received from the DC input port is regulated according to a fourth reference voltage to generate a second regulated DC voltage; A second AC-to-DC converter, adapted to convert the AC power supply received from the AC power input port into a second converted DC voltage based on the fourth reference voltage; and A second control circuit, adapted to monitor the external DC power using a fifth reference voltage, wherein the second control circuit of the second persistent DC power module is adapted to: When the external DC power is detected to be higher than the fifth reference voltage, the second regulated DC voltage is enabled to be delivered to the second DC output port. When the external DC power is detected to be lower than the fifth reference voltage, the second converted DC voltage can be delivered to the second DC output port.

17. The apparatus of claim 16, further comprising a double-pole single-throw switch for manually controlling the on / off state of two phases in the AC power supply.

18. The apparatus according to claim 16, wherein, The persistent DC power module and the second persistent DC power module are installed in a power board where AC and persistent dual DC power coexist.

19. The apparatus according to claim 1, wherein, The AC automatic switch is selected from solid-state relays or electromagnetic relays formed by using bipolar transistors or MOSFET transistors as switch control.

20. The apparatus according to claim 1, further comprising: A second persistent DC power module coupled to a second DC output port, the second persistent DC power module comprising: A second DC voltage regulator, wherein a second external DC power received from the DC input port is regulated according to a fourth reference voltage to generate a second regulated DC voltage; A second AC-to-DC converter, adapted to convert the AC power supply received from the AC power input port into a second converted DC voltage based on the fourth reference voltage; and A second control circuit, adapted to monitor the second external DC power with a fifth reference voltage, wherein the second control circuit of the second persistent DC power module is adapted to: When the second external DC power is detected to be higher than the fifth reference voltage, the second regulated DC voltage is enabled to be delivered to the second DC output port, and When the second external DC power is detected to be lower than the fifth reference voltage, the second converted DC voltage can be delivered to the second DC output port.

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