Power conversion device and power supply system

Abstract

The utility model discloses a kind of power conversion device and power supply system, device includes power conversion unit, power conversion unit is configured with direct current input end, alternating current input end, first output unit, second output unit, switching control circuit;Direct current input end is connected with first output unit, alternating current input end is connected with second output unit, first output unit, second output unit is connected with switching control circuit respectively;First output unit is configured for converting direct current input by direct current input end, second output unit is configured for converting alternating current input by alternating current input end;The output of first output unit, second output unit is identical;Switching control circuit is used to according to control signal, connect first output unit, or connect second output unit.

Description

Technical Field

[0001] This utility model relates to the field of power supply technology, and in particular to a power conversion device and power supply system. Background Technology

[0002] In centralized energy storage systems, UPS (Uninterruptible Power Supply) is an important component for ensuring the continuity of power supply to critical system equipment (such as monitoring systems, control modules, power conversion auxiliary circuits, etc.).

[0003] UPS is typically independent of the main power conversion circuit of PCS, and is dedicated to powering low-power critical control and monitoring equipment. It does not directly participate in the power conversion process of large-scale energy storage charging and discharging.

[0004] In centralized PCS energy storage systems, UPS batteries are typically charged via mains power. The UPS itself requires components such as rectifiers, inverters, and battery packs, necessitating significant space for installation and placement. In the construction of centralized energy storage systems, especially in sites with limited space, UPS installation may be constrained by space limitations, impacting the overall system layout and construction planning.

[0005] In summary, using UPS as a backup power source in centralized energy storage systems has problems such as short backup time and excessively large installation size. Utility Model Content

[0006] This utility model provides a power conversion device and power system to solve at least one defect in the prior art.

[0007] In a first aspect, this utility model proposes a power conversion device, including a power conversion unit, wherein the power conversion unit is configured with a DC input terminal, an AC input terminal, a first output unit, a second output unit, and a switching control circuit;

[0008] The DC input terminal is connected to the first output unit, the AC input terminal is connected to the second output unit, and the first output unit and the second output unit are respectively connected to the switching control circuit;

[0009] The first output unit is configured to convert the DC power input at the DC input terminal, and the second output unit is configured to convert the AC power input at the AC input terminal.

[0010] The switching control circuit is used to connect the first output unit or the second output unit according to the control signal.

[0011] Optionally, the first output unit includes: a DC-DC step-down circuit and a first DC-AC inverter circuit;

[0012] The DC input terminal is connected to the first DCAC inverter circuit via the DC-DC step-down circuit, and the first DCAC inverter circuit is connected to the switching control circuit.

[0013] Optionally, the first output unit further includes: a pre-charging circuit;

[0014] The DC input terminal is connected to the DC-DC step-down circuit through the pre-charging circuit.

[0015] Optionally, the first output unit further includes: a control circuit;

[0016] The control circuit is connected to the pre-charging circuit, the DC-DC step-down circuit, and the first DC-AC inverter circuit, respectively.

[0017] The control circuit is configured to output the drive control signals required for the operation of the DC-DC buck circuit and the first DC-AC inverter circuit. The control circuit is also configured to control the pre-charging circuit to pre-charge the DC-DC buck circuit.

[0018] Optionally, the first output unit further includes: a protection circuit;

[0019] The protection circuit is connected to the control circuit, the pre-charge circuit, the DC-DC step-down circuit, and the first DC-AC inverter circuit.

[0020] The protection circuit is configured to disconnect the faulty circuit in the pre-charging circuit, DC-DC buck circuit, or first DCAC inverter circuit according to the control signal of the control circuit when the pre-charging circuit, DC-DC buck circuit, or first DCAC inverter circuit fails.

[0021] Optionally, the second output unit includes: an AC-DC rectifier circuit and a second DC-AC inverter circuit;

[0022] The AC input terminal is connected to the second DCAC inverter circuit via the AC-DC rectifier circuit, and the second DCAC inverter circuit is connected to the switching control circuit.

[0023] Optionally, the second output unit further includes a filtering circuit;

[0024] The AC input terminal is connected to the AC / DC rectifier circuit through the filter circuit.

[0025] Optionally, the second output unit further includes: a PFC correction circuit;

[0026] The AC-DC rectifier circuit is connected to the second DC-AC inverter circuit through the PFC correction circuit.

[0027] Optionally, the power conversion unit may further include a transformer circuit, a rectifier and filter circuit, and a voltage regulator circuit;

[0028] The switching control circuit outputs AC power through the transformer circuit, rectifier filter circuit, and voltage regulator circuit.

[0029] Secondly, this utility model proposes a power supply system, including any of the power conversion devices described in the embodiments of this utility model.

[0030] Optionally, it also includes an AC / DC unit, the output terminal of which is connected to the AC / DC unit, and the output terminal of which is used to connect to a DC load.

[0031] Optionally, a first circuit breaker may also be included;

[0032] Alternating current is connected to the AC input terminal through the first circuit breaker, which is used to trip when the AC power is disconnected.

[0033] Optionally, a second circuit breaker may also be included;

[0034] The battery pack is connected to the DC input terminal via the second circuit breaker, which is configured to trip when the voltage of the battery pack is lower than a threshold voltage.

[0035] Compared with existing technologies, the advantages of this invention are as follows: This invention proposes a power conversion device, which includes a power conversion unit. This device utilizes the power conversion unit to achieve integrated DC and AC power conversion. Using this device, the cost and installation space required for power systems requiring both DC and AC input can be reduced. The power conversion unit includes a first output unit, a second output unit, and a switching control circuit. It adopts a dual-path parallel inverter and switching control architecture to achieve switching between DC and AC input paths. This device can be applied to power outage emergency scenarios where AC is used as the conventional power source and DC as the backup power source. By selecting a suitable DC power source, it can provide backup power for conventional loads for over 2 hours, meeting the needs of long-term power outage emergencies. Attached Figure Description

[0036] Figure 1 This is a block diagram of the power conversion device in the embodiment;

[0037] Figure 2 This is a block diagram of another power conversion device structure in the embodiment;

[0038] Figure 3 This is a schematic diagram of the power system structure in the embodiment;

[0039] Figure 4This is another power system structure block diagram in the embodiment;

[0040] Figure 5 This is another power system structure block diagram in the embodiment. Detailed Implementation

[0041] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0042] Example 1

[0043] Figure 1 This is a block diagram of the power conversion device in the embodiment, for reference. Figure 1 The device includes a power conversion unit, which is equipped with a DC input terminal, an AC input terminal, a first output unit 201, a second output unit 202, and a switching control circuit 203.

[0044] The DC input terminal is connected to the first output unit 201, and the AC input terminal is connected to the second output unit 202. The first output unit 201 and the second output unit 202 are respectively connected to the switching control circuit 203.

[0045] The first output unit 201 is configured to convert the DC power input at the DC input terminal, and the second output unit 202 is configured to convert the AC power input at the AC input terminal.

[0046] The switching control circuit 203 is used to connect the first output unit 201 or the second output unit 202 according to the control signal.

[0047] In this scheme, the first output unit and the second output unit are configured to output AC power with the same value (or the same value range) (for example, the first output unit and the second output unit both output 220V AC power).

[0048] For example, in this solution, the first output unit 201 is configured for DC-AC conversion, and the second output unit 202 is configured for AC-AC conversion.

[0049] For example, in this solution, the first output unit 201 can use a three-phase full-bridge IGBT inverter circuit to convert the DC power of the battery pack 100 into three-phase AC power of a specified voltage level.

[0050] In this scheme, the three-phase full-bridge IGBT inverter circuit may include a three-phase bridge arm composed of 6 IGBT modules, a DC bus capacitor bank, an output filter inductor, and a filter capacitor forming an LCL filter.

[0051] For example, in this solution, the second output unit 202 may include a rectifier circuit and an inverter circuit. The rectifier circuit is used to rectify the input AC power into DC power of a certain voltage, and the inverter circuit converts the DC power into AC power of a certain voltage level.

[0052] For example, in this solution, the switching control circuit 203 can be designed to include a static switch and a mechanical switch. The static switch can be composed of anti-parallel IGBTs, and the mechanical switch can be a magnetic latching relay.

[0053] For example, in this solution, the mechanical switch in the switching control circuit 203 can be configured to close, and when the static switch is in the off state, the second output unit 202 is connected. When the static switch is on and the mechanical switch is off, the first output unit 201 is connected.

[0054] This embodiment proposes a power conversion device, which includes a power conversion unit. This unit enables integrated DC and AC power conversion, reducing the cost and installation space required for power systems requiring both DC and AC inputs. The power conversion unit includes a first output unit, a second output unit, and a switching control circuit. It employs a dual-path parallel inverter and switching control architecture to switch between DC and AC input paths. This device can be applied to power outage emergency scenarios where AC is used as the primary power source and DC as a backup power source. By selecting a suitable DC power source, it can provide backup power for conventional loads for over 2 hours, meeting the needs of long-term power outage emergencies.

[0055] Based on any of the aforementioned schemes, in one possible implementation scheme, the first output unit includes: a DC-DC step-down circuit and a first DC-AC inverter circuit.

[0056] The DC input terminal is connected to the first DCAC inverter circuit via a DC-DC step-down circuit, and the first DCAC inverter circuit is connected to the switching control circuit.

[0057] For example, in this solution, a two-stage conversion architecture is used to process the high-voltage DC power from the battery pack. A DC-DC step-down circuit is used to reduce the high-voltage voltage of the battery pack to an intermediate voltage suitable for inversion. A first DC-AC inverter circuit is used to convert the stepped-down DC power into AC power.

[0058] In this solution, the input voltage is stepped down once by a DC-DC step-down circuit before being converted into AC power. This optimizes inverter efficiency, avoids switching losses and EMI problems caused by direct high-voltage inverter, and improves system reliability.

[0059] Based on any of the aforementioned schemes, in one possible implementation, the first output unit further includes: a pre-charging circuit; the DC input terminal is connected to the DCDC step-down circuit through the pre-charging circuit.

[0060] In this scheme, the (high voltage) battery pack is connected to the DC-DC step-down circuit through a pre-charging circuit. The pre-charging circuit may include a main contactor K1, a pre-charging contactor K2, and a pre-charging resistor R. The DC input terminal is connected to the DC-DC step-down circuit through the main contactor K1. The pre-charging contactor K2 and the pre-charging resistor R are connected in series and then in parallel across the two ends of the main contactor K1.

[0061] In this scheme, a pre-charging circuit is set up to charge the bus capacitor in the DC-DC step-down circuit. During pre-charging, K1 is open and K2 is closed. The pre-charging resistor R is connected to the circuit. The battery pack voltage charges the bus capacitor through the pre-charging resistor R. When the voltage of the bus capacitor reaches the threshold, the pre-charging is completed. At this time, K1 is closed first, the pre-charging resistor R is shorted, and then K2 is opened, and the pre-charging circuit stops working.

[0062] In this design, the pre-charging circuit serves to prevent the surge current at the moment the battery pack is connected from damaging components such as capacitors and IGBTs in the subsequent circuit.

[0063] Based on any of the aforementioned schemes, in one possible implementation scheme, the second output unit includes: an AC-DC rectifier circuit and a second DC-DC inverter circuit; the AC input terminal is connected to the second DC-DC inverter circuit through the AC-DC rectifier circuit, and the second DC-DC inverter circuit is connected to the switching control circuit.

[0064] In this scheme, the second output unit adopts a two-stage AC-DC-AC conversion architecture to convert external AC power into stable standard AC power. The input AC power is rectified into DC power by an AC-DC rectifier circuit, and then the rectified DC power is inverted back into AC power by a DC-AC inverter circuit before being output to the switching control circuit.

[0065] In this scheme, through the two-stage structure of rectification and inversion, the second output unit can achieve input-output electrical isolation, while its output voltage can be flexibly adjusted and has harmonic suppression capability.

[0066] Based on any of the aforementioned schemes, in one possible implementation scheme, the second output unit further includes: a filter circuit; the AC input terminal is connected to the ACDC rectifier circuit through the filter circuit.

[0067] In this solution, a filter circuit is used to suppress harmonics on the mains side. This circuit can filter out high-frequency harmonics (such as the 5th, 7th, and 11th harmonics) in the input AC power, preventing them from entering the AC-DC rectifier circuit. The filter circuit can also reduce EMI interference, buffer mains voltage fluctuations and surges, and extend the lifespan of power devices such as IGBTs in subsequent circuits.

[0068] For example, in this solution, the filter circuit can be designed as a third-order LCL filter circuit, which may include a common-mode inductor Lc, a differential-mode inductor L1, a filter capacitor C, X capacitors (Cx1, Cx2), and Y capacitor Cy.

[0069] Among them, the common-mode inductor Lc is used to suppress common-mode interference, the differential-mode inductor L1 is used to suppress differential-mode harmonics, the X capacitors Cx1 and Cx2 are used to suppress differential-mode high-frequency noise, and the Y capacitor Cy is used to suppress common-mode high-frequency noise.

[0070] Based on any of the aforementioned schemes, in one possible implementation, the second output unit further includes: a PFC correction circuit; the AC-DC rectifier circuit is connected to the second DC-AC inverter circuit through the PFC correction circuit.

[0071] In this scheme, a PFC correction circuit is set between the AC-DC rectifier circuit and the second DC-AC inverter circuit. The AC-DC rectifier circuit first converts the input AC power into DC power; the PFC correction circuit intervenes to optimize the rectified DC voltage, improve the power factor, and reduce current harmonics; finally, the second DC-AC inverter circuit inverts the optimized DC power into standard AC power output.

[0072] By adding a PFC correction circuit, the problems of low power factor and high harmonics in traditional rectifier circuits are effectively solved, making the power supply system more efficient and stable.

[0073] For example, in this solution, the PFC correction circuit typically adopts a Boost converter topology, which may include power switching devices, a boost inductor, an output filter capacitor, a control chip, and a sampling circuit.

[0074] Power switching devices are used for high-frequency switching control. Boost inductors store and release energy to boost the voltage. Output filter capacitors smooth the output voltage. The control chip executes the PFC control algorithm, controlling the on / off state of the power switching devices. Sampling circuits monitor input voltage, current, and output voltage, providing feedback signals to the control chip.

[0075] For example, in this solution, PFC control includes voltage outer loop control, current inner loop control, and switching control.

[0076] Among them, the voltage outer loop control obtains an error signal by sampling the output DC voltage and comparing it with the reference voltage. The error signal is then used as the reference amplitude of the current inner loop after passing through the PID regulator.

[0077] The inner current loop control compares the sampled input current with the reference current amplitude output by the outer voltage loop, and generates a PWM signal through the current regulator.

[0078] The PWM signal serves as the control signal in switching control, driving the power switching device to make the input current waveform track the input voltage waveform, thereby improving the power factor to close to 1 and reducing the current harmonic content.

[0079] In this scheme, the PFC correction circuit can improve the power factor, reduce reactive power loss, increase grid transmission efficiency, and reduce line losses and equipment capacity requirements. It can also reduce input current harmonic content, avoiding harmonic interference to the grid and other equipment. Furthermore, the PFC correction circuit can provide a stable DC voltage to the second DCAC inverter circuit, thereby improving the power quality of the inverter output.

[0080] Based on any of the aforementioned schemes, in one possible implementation scheme, the voltage stabilizing unit includes: a transformer circuit, a rectifier filter circuit, and a voltage stabilizing circuit; the switching control circuit is connected to the first output terminal and the second output terminal through the transformer circuit, the rectifier filter circuit, and the voltage stabilizing circuit.

[0081] For example, in this solution, the transformer circuit is used to convert the input voltage to the required voltage according to the turns ratio. The isolation transformer in the transformer circuit can also be used for electrical isolation between the primary and secondary sides, improving safety.

[0082] For example, in this solution, the rectifier and filter circuit may include a bidirectional thyristor rectifier bridge and an LC filter network. The bidirectional thyristor rectifier bridge may consist of four bidirectional thyristors to achieve full-wave rectification control of the AC power. The conduction angle of the thyristors can be driven by an optocoupler-isolated driver chip.

[0083] An LC filter network can include a filter inductor, a filter capacitor, and a sampling circuit. The LC filter network is used to process the input AC power into AC power with low harmonics and stable amplitude.

[0084] In this scheme, the amplitude of the output voltage can be controlled by adjusting the conduction angle of the thyristor. By utilizing the LC series resonance characteristics, high-frequency harmonics such as the 5th and 7th can be filtered out, so that the output voltage is a low-harmonic AC voltage.

[0085] For example, in this solution, the voltage regulator circuit can adopt a closed-loop feedback architecture design. The voltage regulator circuit may include a voltage sampling module, a DSP main control chip, a reference voltage source, a solid-state relay, and a compensation transformer.

[0086] When the voltage regulator circuit is working, the voltage sampling module sends the sampled voltage to the ADC channel of the DSP main control chip. The DSP main control chip compares the sampled voltage with the reference voltage to obtain the voltage deviation. Based on the voltage deviation, PID control is used to generate a control signal, which controls the solid-state relay to switch the taps of the compensation transformer, thereby adjusting the voltage.

[0087] Figure 2 This is a block diagram of another power conversion device structure in the embodiment, see reference. Figure 2 Based on any of the aforementioned schemes, in one possible implementation, the device includes a first output unit, a second output unit, a switching control circuit 203, and a voltage regulator unit.

[0088] The first output unit includes a pre-charge circuit 2011, a DC-DC step-down circuit 2012, a first DC-AC inverter circuit 2013, a control circuit 2014, and a protection circuit 2015. The battery pack 100 is connected to the switching control circuit 203 through the pre-charge circuit 2011, the DC-DC step-down circuit 2012, and the first DC-AC inverter circuit 2013.

[0089] The control circuit 2014 is connected to the pre-charging circuit 2011, the DC-DC step-down circuit 2012, and the first DC-AC inverter circuit 2013, respectively, and the protection circuit 2015 is connected to the control circuit 2014.

[0090] The second output unit includes a filter circuit 2021, an AC / DC rectifier circuit 2022, a PFC correction circuit 2023, and a second DC / AC inverter circuit 2024. Alternating current is connected to the switching control circuit 203 through the filter circuit 2021, the AC / DC rectifier circuit 2022, the PFC correction circuit 2023, and the second DC / AC inverter circuit 2024.

[0091] The voltage regulator unit includes a transformer circuit 2041, a rectifier-filter circuit 2042, and a voltage regulator circuit 2043. The switching control circuit 203 is connected to the voltage regulator circuit 2043 via the transformer circuit 2041 and the rectifier-filter circuit 2042. The voltage regulator circuit 2043 has a first output terminal and a second output terminal.

[0092] In this scheme, the control circuit 2014 is connected to the pre-charging circuit, the DC-DC step-down circuit 2012, and the first DCAC inverter circuit 2013 respectively. The control circuit 2014 is configured to output the drive control signals required for the operation of the DC-DC step-down circuit 2012 and the first DCAC inverter circuit 2013. The control circuit 2014 is also configured to control the pre-charging circuit 2011 to pre-charge the DC-DC step-down circuit 2012.

[0093] In this scheme, the control circuit 2014 can be configured to control the pre-charging resistor R to pre-charge or stop the pre-charging of the bus capacitor in the DC-DC step-down circuit by controlling the on / off state of the main contactor K1 and the pre-charging contactor K2 (in the pre-charging circuit 2011).

[0094] For example, in this solution, the configuration control circuit 2014 is used to coordinate the working status of the pre-charging circuit 2011, the DC-DC step-down circuit 2012, and the first DC-AC inverter circuit 2013 to achieve precise control of the battery pack energy.

[0095] The control circuit 2014 can be specifically configured to adjust the duty cycle of the DC-DC step-down circuit 2012 and the output frequency / amplitude of the first DC-AC inverter circuit 2013 in real time to adapt to the system load requirements.

[0096] For example, in this solution, the control circuit 2014 may include a main control chip, a sampling circuit, and a drive circuit. The main control chip outputs drive control signals to the DC-DC buck circuit 2012 and the first DC-AC inverter circuit 2013 through the drive circuit. The sampling circuit may be configured to be connected in parallel with the pre-charge circuit 2011, and collects the voltage of the battery pack 100, the current of the DC-DC buck circuit 2012, etc., based on the pre-charge circuit 2011, so that the main control chip can generate the specified drive control signal.

[0097] In this scheme, the protection circuit 2015 is connected to the control circuit 2014, the pre-charge circuit 2011, the DC-DC step-down circuit 2012, and the first DC-AC inverter circuit 2013.

[0098] The protection circuit 2015 is configured to disconnect the faulty circuit in the pre-charge circuit 2011, DC-DC step-down circuit 2012, or first DCAC inverter circuit 2013 according to the control signal of the control circuit 2014 when the pre-charge circuit 2011, DC-DC step-down circuit 2012, or first DCAC inverter circuit 2013 fails.

[0099] For example, in this solution, the protection circuit 2015 can be configured to monitor the abnormal operating conditions (such as overvoltage, overcurrent, short circuit, overheating, etc.) of the battery pack 100, the DC-DC step-down circuit 2012, and the first DC-AC inverter circuit 2013 in real time. When an abnormal operating condition occurs, the corresponding protection action (such as current limiting, power reduction, driving the relay to open, etc.) is triggered.

[0100] For example, in this solution, the protection circuit 2015 may be configured with a voltage comparator (for voltage detection), a current sensor (for current detection), and a temperature sensor (for temperature detection). The protection circuit 2015 may also include a relay for disconnecting the faulty circuit in the pre-charging circuit 2011, the DC-DC step-down circuit 2012, and the first DC-AC inverter circuit 2013.

[0101] Example 2

[0102] This embodiment proposes a power supply system, including any of the power conversion devices described in Embodiment 1. The implementation methods and beneficial effects of the power conversion devices are the same as those described in Embodiment 1, and the specific details will not be repeated here.

[0103] Figure 3 This is a schematic diagram of the power system structure in the embodiment, for reference. Figure 3 Based on any of the aforementioned schemes, in one possible implementation, the power supply system further includes an AC / DC unit 300, the output terminal of the power conversion unit 200 in the power conversion device is connected to the AC / DC unit 300, and the output terminal of the AC / DC unit 300 is used to connect to a DC load.

[0104] For example, in this solution, the power conversion unit 200 is configured with a first output terminal and a second output terminal, and the first output terminal and the second output terminal output AC power (e.g., AC220V) with the same value.

[0105] For example, in this solution, one AC power can be output by switching the control circuit. It can be configured to split one AC power into two outputs by connecting two wires in parallel, and the two AC power are set to be output through the first output terminal and the second output terminal respectively.

[0106] This solution does not limit the method of splitting one AC power supply into two outputs. Other methods can also be used to split one AC power supply into two outputs, such as using a two-way distributor.

[0107] In this scheme, the first output terminal is specifically configured to be connected to the AC / DC unit 300, the second output terminal is configured to be connected to the first load, and the output terminal of the AC / DC unit 300 is configured to be connected to the second load.

[0108] For example, in this solution, the first load (AC load) may include a dehumidifier, water immersion unit, liquid chiller, and PCS (Power Conversion System, energy storage converter), and the second load (DC load) may include BMS, switch, EMS (Energy Management System, energy storage management system), and fire protection (equipment).

[0109] Figure 4 This is another power system structure block diagram in the embodiment, see reference. Figure 4 Based on any of the aforementioned schemes, in one possible implementation scheme, a first circuit breaker 501 is also included;

[0110] The AC power is connected to the AC input terminal through the first circuit breaker 501, which is used to trip when the AC power is disconnected.

[0111] In this scheme, AC power (such as mains power) is connected to the AC input terminal through the first circuit breaker 501. When the AC power is abnormal, the first circuit breaker 501 trips, cutting off the connection with the downstream circuit.

[0112] For example, in this solution, the first circuit breaker 501 can be an electromagnetic circuit breaker. When the trip coil of the first circuit breaker 501 is activated, the mechanical structure triggers the trip.

[0113] refer to Figure 4 Based on any of the aforementioned schemes, in one possible implementation scheme, a second circuit breaker 502 is also included;

[0114] The battery pack is connected to the DC input terminal via a second circuit breaker 502, which is configured to trip when the battery pack voltage is lower than a threshold voltage.

[0115] In this scheme, the second circuit breaker 502 is connected in series between the battery pack and the DC input terminal, serving as a key protection device for the battery pack discharge circuit.

[0116] When the battery pack voltage drops to a preset threshold voltage, the second circuit breaker 502 trips quickly, disconnecting the battery pack from the system. The second circuit breaker 502 prevents damage to downstream circuits caused by low battery voltage, ensuring the stability and reliability of the entire power system.

[0117] In this scheme, a trip signal can be manually generated when the battery pack voltage is lower than the threshold voltage. The trip signal drives the shunt trip coil of the circuit breaker. After the trip coil is energized, the circuit breaker contacts are separated through a mechanical mechanism, thus achieving the tripping action.

[0118] Figure 5 This is another power system structure block diagram in the embodiment, see reference. Figure 5 Based on any of the aforementioned schemes, in one possible implementation scheme, the first circuit breaker 501 is equipped with an undervoltage coil MN and an auxiliary contact OF2. The undervoltage coil MN has the function of coil energizing when the voltage at both ends is lost, and miniature circuit breaker tripping.

[0119] For example, in this solution, the auxiliary contact OF2 of the first circuit breaker 501 is configured to be connected to a designated control unit. The control unit can be used to determine the opening and closing status of the first circuit breaker 501 based on the on / off status of the auxiliary contact OF2.

[0120] refer to Figure 5 Based on any of the aforementioned schemes, in one possible implementation scheme, the second circuit breaker 502 is configured with a shunt coil MX1 and an auxiliary contact OF1.

[0121] In this scheme, the trip command is set to act on the shunt coil MX1 of the second circuit breaker 502, thereby controlling the second circuit breaker 502 to trip.

[0122] For example, in this solution, the auxiliary contact OF1 of the second circuit breaker 502 is configured to be connected to a designated control unit. The control unit can be used to determine the opening and closing status of the second circuit breaker 502 based on the on / off status of the auxiliary contact OF1.

[0123] refer to Figure 5 Based on any of the aforementioned schemes, in one possible implementation, the power system includes a power conversion unit 200, an AC / DC unit 300, a first circuit breaker 501, a second circuit breaker 502, and a battery pack.

[0124] The power conversion unit 200 is equipped with a DC input terminal (DC+, DC-), an AC input terminal (L, N), a first output terminal (L1, N1), and a second output terminal (L2, N2).

[0125] The battery pack is connected to the DC input terminal via the second circuit breaker 502, and the AC input terminal is connected to the mains power via the first circuit breaker 501.

[0126] The first output terminal is used to connect to the AC / DC unit 300, the second output terminal is used to connect to the first load, and the output terminal of the AC / DC unit 300 is used to connect to the second load.

[0127] For example, in this solution, the power system operates as follows:

[0128] When the mains power supply is normal, the AC input terminal is powered. When the mains power fails (or is undervoltage), the first circuit breaker 501 trips. The second circuit breaker 502 is connected to the BMS of the battery pack 100. When the BMS detects that the cell voltage of the battery pack is too low, the BMS controls the second circuit breaker 502 to trip to prevent the cells from being over-discharged. When the mains power is restored, the power supply switches back to the AC input terminal.

[0129] For example, in this solution, when the mains power is normal, the first circuit breaker 501 and the second circuit breaker 502 are set to be in the closed state. At this time, the mains power (AC120V~AC277V) is supplied, the second AC output unit of the AC-DC / AC unit 200 is turned on, the AC / DC unit 300 is turned on, the first output terminal and the second output terminal are turned on, outputting 220V AC power, and the AC / DC unit 300 outputs 24V DC power.

[0130] When the mains power supply is interrupted, the undervoltage coil MN of the first circuit breaker 501 is activated, the first circuit breaker 501 is tripped, the AC-DC / AC unit 200 switches to the first AC output unit and is powered by the battery pack 100.

[0131] When the BMS detects that the voltage of a single cell in the battery pack 100 is too low (exceeding the set threshold), the BMS sends a trip command to the shunt coil MX1 of the second circuit breaker 502. The second circuit breaker 502 trips, forcibly disconnecting the battery pack 100 from the first and second loads to prevent the cells from being over-discharged and damaged. At this time, the first and second output terminals are de-energized.

[0132] When the mains power is restored, the AC-DC / AC unit 200 switches to the second AC output unit and continues the above cycle.

[0133] For example, in this solution, the auxiliary contact OF2 of the first circuit breaker 501 and the auxiliary contact OF1 of the second circuit breaker 502 are configured to be connected to the BMS. The BMS is configured to determine the opening and closing states of the first circuit breaker 501 and the second circuit breaker 502 according to the on / off state of the auxiliary contacts.

[0134] For example, in this solution, when switching from battery power to AC power, the BMS can be configured to send a closing command to the undervoltage coil MN of the first circuit breaker 501 to control the undervoltage coil MN to close.

[0135] For example, in this solution, the BMS can also be configured to determine whether the opening and closing operation of the first circuit breaker 501 or the second circuit breaker 502 is successful based on the opening and closing status of the first circuit breaker 501 and the second circuit breaker 502. If it fails, a preset operation can be performed (such as alarm or resending control commands).

[0136] This solution uses battery power as a backup power source, replacing traditional UPS power, and can achieve a backup power duration of over 2 hours. Both 220V AC and 24V DC loads are included in the backup power scope, improving the overall system reliability compared to traditional solutions that only use 24V DC loads as backup. The AC input supports a wide voltage range of 120-227V, adaptable to single-phase voltages in most countries worldwide. Using an AC-DC / AC power conversion module instead of a UPS and backup battery saves installation space.

[0137] This solution employs a power conversion unit, an AC / DC unit, a first circuit breaker, a second circuit breaker, and a battery pack to form a complete auxiliary power control system. This enables extended backup power, improves system reliability, and allows for smaller module sizes, requiring less installation space and resulting in lower costs.

[0138] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A power conversion device, characterized in that, It includes a power conversion unit, which is configured with a DC input terminal, an AC input terminal, a first output unit, a second output unit, and a switching control circuit; The DC input terminal is connected to the first output unit, the AC input terminal is connected to the second output unit, and the first output unit and the second output unit are respectively connected to the switching control circuit; The first output unit is configured to convert the DC power input at the DC input terminal, and the second output unit is configured to convert the AC power input at the AC input terminal. The switching control circuit is used to connect the first output unit or the second output unit according to the control signal.

2. The power conversion device as described in claim 1, characterized in that, The first output unit includes: a DC-DC step-down circuit and a first DC-AC inverter circuit; The DC input terminal is connected to the first DCAC inverter circuit via the DC-DC step-down circuit, and the first DCAC inverter circuit is connected to the switching control circuit.

3. The power conversion device as described in claim 2, characterized in that, The first output unit further includes: a pre-charging circuit; The DC input terminal is connected to the DC-DC step-down circuit through the pre-charging circuit.

4. The power conversion device as described in claim 3, characterized in that, The first output unit further includes: a control circuit; The control circuit is connected to the pre-charging circuit, the DC-DC step-down circuit, and the first DC-AC inverter circuit, respectively. The control circuit is configured to output the drive control signals required for the operation of the DC-DC buck circuit and the first DC-AC inverter circuit. The control circuit is also configured to control the pre-charging circuit to pre-charge the DC-DC buck circuit.

5. The power conversion device as described in claim 4, characterized in that, The first output unit further includes: a protection circuit; The protection circuit is connected to the control circuit, the pre-charge circuit, the DC-DC step-down circuit, and the first DC-AC inverter circuit. The protection circuit is configured to disconnect the faulty circuit in the pre-charging circuit, DC-DC buck circuit, or first DCAC inverter circuit according to the control signal of the control circuit when the pre-charging circuit, DC-DC buck circuit, or first DCAC inverter circuit fails.

6. The power conversion device according to any one of claims 1 to 5, characterized in that, The second output unit includes: an AC-DC rectifier circuit and a second DC-AC inverter circuit; The AC input terminal is connected to the second DCAC inverter circuit via the AC-DC rectifier circuit, and the second DCAC inverter circuit is connected to the switching control circuit.

7. The power conversion device as described in claim 6, characterized in that, The second output unit further includes: a filter circuit; The AC input terminal is connected to the AC / DC rectifier circuit through the filter circuit.

8. The power conversion device as described in claim 6, characterized in that, The second output unit further includes: a PFC correction circuit; The AC-DC rectifier circuit is connected to the second DC-AC inverter circuit through the PFC correction circuit.

9. The power conversion device according to any one of claims 1 to 5, characterized in that, The power conversion unit also includes a transformer circuit, a rectifier and filter circuit, and a voltage regulator circuit; The switching control circuit outputs AC power through the transformer circuit, rectifier filter circuit, and voltage regulator circuit.

10. A power supply system, characterized in that, Includes the power conversion device according to any one of claims 1 to 9.

11. The power supply system as claimed in claim 10, characterized in that, It also includes an AC / DC unit, the output terminal of which is connected to the AC / DC unit, and the output terminal of which is used to connect to a DC load.

12. The power supply system as claimed in claim 10, characterized in that, It also includes the first circuit breaker; Alternating current is connected to the AC input terminal through the first circuit breaker, which is used to trip when the AC power is disconnected.

13. The power supply system as claimed in claim 10, characterized in that, It also includes a second circuit breaker; The battery pack is connected to the DC input terminal via the second circuit breaker, which is configured to trip when the voltage of the battery pack is lower than a threshold voltage.

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