Parallel charging circuit for multiple ups battery packs based on magnetic coupling current sharing

Abstract

The utility model relates to a multi-UPS battery pack parallel charging circuit based on magnetic coupling current sharing belongs to charging circuit technical field. Circuit contains main charging circuit, magnetic coupling current sharing circuit, current sampling circuit, first operational amplifier unit, second operational amplifier unit, third operational amplifier unit and control circuit, the input of main charging circuit connects commercial power, the positive pole of main charging circuit connects the positive pole of battery pack through the first winding port of magnetic coupling current sharing circuit, the negative pole of battery pack connects the negative pole of main charging circuit through current sampling circuit, the input of first operational amplifier unit connects current sampling circuit both ends, and the output connects control circuit, the input of second operational amplifier unit connects the positive pole and the negative pole of battery pack, and the output connects control circuit, the input of third operational amplifier unit connects the voltage detection node of the second winding port of magnetic coupling current sharing circuit, and the output connects control circuit. The utility model can restrain charging branch current deviation, realizes the dynamic balance of battery pack charging current.

Description

Technical Field

[0001] This utility model relates to the field of charging circuit technology, and more specifically to a parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing. Background Technology

[0002] In UPS (Uninterruptible Power Supply) systems, parallel charging of multiple battery banks can improve charging efficiency and system reliability. Currently, the structure of parallel charging circuits for multiple battery banks needs to consider power conversion, balancing control, status monitoring, and safety protection. It mainly includes: a main charging power supply circuit, a battery balancing circuit, a status monitoring circuit, a protection circuit, and a control circuit. During charging, the AC / DC converter in the main charging power supply circuit rectifies the mains power into high-voltage DC, which is then converted by a DC / DC converter to the charging voltage required by the battery banks, providing energy for charging. If the voltage of one battery bank is higher than that of the others, the balancing circuit balances the charging voltage.

[0003] However, multiple parallel battery packs will have current deviations during charging, resulting in uneven current distribution. Current battery balancing circuits use voltage as the balancing indicator and mainly solve the problem of voltage imbalance in series battery packs. However, their circuit structure and adjustment principle are not suitable for solving the problem of uneven charging current distribution, so further improvements are needed. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing, thereby solving the technical problem of uneven current distribution when multiple battery packs are charged in parallel in existing technologies.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This utility model provides a parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing, applicable to multiple UPS battery packs. It includes a main charging circuit, a magnetic coupling current sharing circuit, a current sampling circuit, a first operational amplifier unit, a second operational amplifier unit, a third operational amplifier unit, and a control circuit; wherein...

[0007] The multi-UPS battery pack is composed of multiple UPS battery packs connected in parallel, and the negative terminals of the multiple UPS battery packs are connected in parallel to form the common negative terminal of the multi-UPS battery pack.

[0008] The input terminal of the main charging circuit is connected to the mains power, and the positive output terminal of the main charging circuit is connected to the positive terminal of the multi-UPS battery pack via the first winding port of the magnetic coupling current sharing circuit. The common negative terminal of the multi-UPS battery pack is connected to the negative output terminal of the main charging circuit via the current sampling circuit.

[0009] The input terminal of the first operational amplifier unit is connected to both ends of the current sampling circuit, and the output terminal of the first operational amplifier unit is connected to the input terminal of the control circuit.

[0010] The input terminal of the second operational amplifier unit is connected to the positive and negative terminals of the multi-UPS battery pack, and the output terminal of the second operational amplifier unit is connected to the input terminal of the control circuit.

[0011] The input terminal of the third operational amplifier unit is connected to the voltage detection node of the second winding port of the magnetically coupled current sharing circuit, and the output terminal of the third operational amplifier unit is connected to the input terminal of the control circuit.

[0012] The output terminal of the current sampling circuit is connected to the input terminal of the control circuit, and the output terminal of the control circuit is connected to the driving terminal of the main charging circuit and the adjustment node of the second winding port.

[0013] Preferably, the magnetically coupled current-sharing circuit includes a magnetically coupled transformer group, a current-sharing inductor, a freewheeling diode, and a controllable impedance unit; wherein,

[0014] The magnetic coupling transformer group includes multiple magnetic coupling transformers, each of which consists of a primary winding and a secondary winding with a common magnetic core.

[0015] The first end of the primary winding is connected to the positive output terminal of the main charging circuit, and the second end of the primary winding is connected to the positive terminal of each UPS battery pack via a current sharing inductor.

[0016] The freewheeling diode is connected in reverse parallel to the first and second ends of the primary winding;

[0017] The output terminals of adjacent secondary windings are connected in reverse series to form a secondary reverse series circuit. A controllable impedance unit is connected in series in the secondary reverse series circuit. The driving terminal of the controllable impedance unit is connected to the output terminal of the control circuit.

[0018] The secondary reverse series circuit is equipped with a voltage detection node, which is connected to the input terminal of the third operational amplifier unit.

[0019] Preferably, the main charging circuit includes an AC-DC rectifier bridge, a filter capacitor, a DC-DC converter, and an isolation transformer;

[0020] The input terminal of the AC-DC rectifier bridge is used to connect to the mains power, and the output terminal of the AC-DC rectifier bridge is connected to the input terminal of the DC-DC converter via a filter capacitor.

[0021] The output terminal of the DC-DC converter is connected to the input terminal of the isolation transformer, and the drive terminal of the DC-DC converter is connected to the output terminal of the control circuit.

[0022] The output terminal of the isolation transformer is connected to the first terminal of the primary winding.

[0023] Preferably, the control circuit includes a microcontroller, an analog-to-digital converter, and a drive circuit; wherein,

[0024] The input terminals of the analog-to-digital converter are connected to the output terminals of the current sampling circuit, the first operational amplifier unit, the second operational amplifier unit, and the third operational amplifier unit, respectively. The output terminal of the analog-to-digital converter is connected to the input terminal of the microcontroller.

[0025] The output of the microcontroller is connected to the drive terminal of the DC-DC converter and the drive terminal of the controllable impedance unit via a drive circuit.

[0026] Preferably, the parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing further includes an overvoltage detection circuit, an overcurrent detection circuit, and a relay; wherein,

[0027] The input terminal of the overvoltage detection circuit is connected to the output terminal of the third operational amplifier unit, and the output terminal of the overvoltage detection circuit is connected to the input terminal of the microcontroller and the control terminal of the relay, respectively.

[0028] The input terminal of the overcurrent detection circuit is connected to the common negative terminal of the multiple UPS battery packs, and the output terminal of the overcurrent detection circuit is connected to the input terminal of the microcontroller and the control terminal of the relay respectively.

[0029] The output terminal of the microcontroller is connected to the control terminal of the relay, and the contact terminal of the relay is connected to the input terminal of the main charging circuit.

[0030] Preferably, the current sampling circuit includes multiple branch sampling resistors and a total current sampling resistor; wherein,

[0031] The first end of the branch sampling resistor is connected to the negative terminal of the UPS battery pack, and the second end of the branch sampling resistor is connected to the common negative terminal of multiple UPS battery packs.

[0032] The input terminals of the first operational amplifier unit are respectively connected to the first and second terminals of the branch sampling resistor;

[0033] The first end of the total current sampling resistor is connected to the common negative terminal of the multiple UPS battery packs, and the second end of the total current sampling resistor is connected to the negative output terminal of the main charging circuit.

[0034] Preferably, the first operational amplifier unit includes a first analog switch, a second analog switch, and a differential amplifier; wherein, the input channel of the first analog switch is connected to the first terminal of a plurality of branch sampling resistors, and the input channel of the second analog switch is connected to the second terminal of a plurality of branch sampling resistors.

[0035] The common output terminal of the first analog switch and the common output terminal of the second analog switch are respectively connected to the input terminal of the differential amplifier, and the output terminal of the differential amplifier is connected to the input terminal of the microcontroller.

[0036] The enable terminals of the first analog switch and the second analog switch are respectively connected to the output terminals of the microcontroller.

[0037] In summary, this utility model has the following beneficial effects:

[0038] This invention provides a parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing. In this circuit, the magnetic coupling current sharing circuit forms a series loop with the main charging circuit and the multiple UPS battery packs through the first winding port. The voltage detection node at the second winding port, along with the third operational amplifier unit and the control circuit, forms a feedback regulation link. When the charging current of multiple UPS batteries is uneven due to differences in internal resistance, aging, etc., the magnetic coupling current sharing circuit can utilize the electromagnetic coupling characteristics between the windings to convert the current difference between each branch into a voltage change at the second winding port. The control circuit collects this voltage signal in real time through the third operational amplifier unit, adjusts the adjustment node parameters at the second winding port, and then dynamically balances the current distribution of each primary winding in the magnetic coupling current sharing circuit through magnetic coupling, fundamentally suppressing the current deviation of the charging branches and achieving dynamic current balance. Attached Figure Description

[0039] Figure 1 This is a block diagram of the parallel charging circuit principle of multiple UPS battery packs based on magnetic coupling current sharing according to this utility model;

[0040] Figure 2 This is a schematic diagram of the magnetic coupling current sharing circuit of this utility model;

[0041] Figure 3 This is a schematic diagram of the connection of the secondary winding of the magnetic coupling transformer of this utility model;

[0042] Figure 4 This is the schematic diagram of the main charging circuit of this utility model;

[0043] Figure 5 This is the schematic diagram of the control circuit of this utility model;

[0044] Figure 6 This is a schematic diagram of the current sampling circuit of this utility model;

[0045] Figure 7 This is the schematic diagram of the first operational amplifier unit of this utility model. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to the accompanying drawings.

[0047] To make the objectives, solutions, and advantages of this utility model clearer, the following detailed description of this utility model is provided in conjunction with the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0048] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement the present invention. In other embodiments, well-known structures, circuits, materials, or methods are not specifically described in order to avoid obscuring the present invention.

[0049] The following is in conjunction with the appendix of this utility model. Figures 1-7 The embodiments of this utility model will be described in detail below.

[0050] Example 1:

[0051] In this embodiment, a parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing is applied to multiple UPS battery packs, including a main charging circuit, a magnetic coupling current sharing circuit, a current sampling circuit, a first operational amplifier unit, a second operational amplifier unit, a third operational amplifier unit, and a control circuit. Among these,

[0052] A multi-UPS battery pack is composed of multiple UPS battery packs connected in parallel, with the negative terminals of the multiple UPS battery packs connected in parallel to form the common negative terminal of the multi-UPS battery pack.

[0053] The input terminal of the main charging circuit is connected to the mains power. The positive output terminal of the main charging circuit is connected to the positive terminal of the multi-UPS battery pack via the first winding port of the magnetic coupling current sharing circuit. The common negative terminal of the multi-UPS battery pack is connected to the negative output terminal of the main charging circuit via the current sampling circuit.

[0054] The input terminal of the first operational amplifier unit is connected to both ends of the current sampling circuit, and the output terminal of the first operational amplifier unit is connected to the input terminal of the control circuit. The first operational amplifier unit is used to amplify the current sampling signal at both ends of the current sampling circuit.

[0055] The input terminal of the second operational amplifier unit is connected to the positive and negative terminals of the multi-UPS battery pack, and the output terminal of the second operational amplifier unit is connected to the input terminal of the control circuit. The second operational amplifier unit is used to collect and amplify the voltage across the multi-UPS battery pack.

[0056] The input terminal of the third operational amplifier unit is connected to the voltage detection node of the second winding port of the magnetic coupling current sharing circuit, and the output terminal of the third operational amplifier unit is connected to the input terminal of the control circuit. The third operational amplifier unit is used to acquire and amplify the magnetic coupling compensation voltage in the magnetic coupling current sharing circuit.

[0057] The output of the current sampling circuit is connected to the input of the control circuit, and the output of the control circuit is connected to the drive terminal of the main charging circuit and the adjustment node of the second winding port.

[0058] In this embodiment, the main charging circuit provides the basic charging current, the magnetic coupling current sharing circuit dynamically adjusts the current distribution of each group, the current sampling circuit and the three operational amplifier units sample the current and voltage data respectively, and feed the collected current and voltage data back to the control circuit to achieve closed-loop regulation.

[0059] In this embodiment, refer to Figure 2 As shown, the magnetically coupled current-sharing circuit includes a magnetically coupled transformer group, a current-sharing inductor, a freewheeling diode, and a controllable impedance unit. The number of current-sharing inductors is the same as the number of UPS battery packs, denoted by L1 to Ln, where n is the number of UPS battery packs. Each UPS battery pack is connected in series with a current-sharing inductor. The inductance value is designed according to the battery pack capacity, utilizing the energy storage characteristics of the inductor to suppress current surges and provide a basis for magnetic coupling regulation.

[0060] The freewheeling diodes are denoted as VD1 to VDn, where n is the number of UPS battery packs. The freewheeling diodes are used to provide a freewheeling path for the inductor when the primary winding current of the magnetically coupled transformer is interrupted, preventing excessive voltage from damaging components.

[0061] A magnetic coupling transformer bank contains multiple magnetic coupling transformers, denoted as T2~Tn. Each magnetic coupling transformer consists of a primary winding and a secondary winding with a common magnetic core. When the currents in each group are unbalanced, the transformer generates an induced electromotive force, forming a compensation current that forces the currents in each group to tend to be consistent.

[0062] The first end of the primary winding of each magnetically coupled transformer is connected to the positive output terminal of the main charging circuit, and the second end of the primary winding is connected to the positive terminal of each UPS battery pack via a current-sharing inductor. For example, the current path of the primary winding is as follows: T2 primary winding → L1 → positive terminal of battery pack 1, T3 primary winding → L2 → positive terminal of battery pack 2.

[0063] The freewheeling diode is connected in reverse parallel to the first and second terminals of the primary winding. Specifically, a 1N5822 Schottky diode can be used. The anode of the freewheeling diode is connected to the low-potential terminal of the primary winding, i.e., the terminal where the primary winding is connected to the current-sharing inductor. The cathode of the freewheeling diode is connected to the high-potential terminal of the primary winding, i.e., the terminal where the primary winding is connected to the positive output terminal of the main charging circuit. The freewheeling diode is used to absorb the reverse electromotive force generated when the inductor / transformer winding switches between states, preventing high voltage from damaging switching elements (such as MOSFETs), and at the same time providing a release path for the stored energy.

[0064] Reference Figure 3As shown, the output terminals of adjacent secondary windings are connected in reverse series to form a secondary reverse series loop. A controllable impedance unit is connected in series in this secondary reverse series loop, and the driving terminal of the controllable impedance unit is connected to the output terminal of the control circuit. Specifically, in some embodiments, the controllable impedance unit is a controllable MOSFET (field-effect transistor), denoted by Q1~Qn. The control circuit changes the loop current by adjusting the impedance of the controllable MOSFET, indirectly affecting the induced electromotive force of the primary winding, thereby achieving active current sharing compensation.

[0065] The secondary reverse series circuit has a voltage detection node, which is connected to the input terminal of the third operational amplifier unit.

[0066] The secondary windings of each magnetically coupled transformer are connected in series sequentially with opposite terminals of the same name. That is, the non-same-name terminal (let's call it the tail end) of the secondary winding of T2 is connected to the same-name terminal (let's call it the head end) of the secondary winding of T3; the tail end of the secondary winding of T3 is connected to the head end of the secondary winding of T4, and so on. The tail end of the secondary winding of the last transformer (Tn) is connected to the head end of the secondary winding of T2, forming a closed loop, i.e., a secondary reverse series loop. In the secondary reverse series loop, the drain (D) of the controllable MOSFET is connected to the tail end of a secondary winding, the source (S) is connected to the head end of the next secondary winding, and the gate (G) serves as the drive terminal, connected to the control circuit. The on-resistance (0~Ron) of the controllable MOSFET is adjusted according to the PWM duty cycle in the PWM signal output by the control circuit, thus changing the equivalent impedance of the secondary reverse series loop.

[0067] In this embodiment, refer to Figure 4 As shown, the main charging circuit includes an AC-DC rectifier bridge, a filter capacitor, a DC-DC converter, and an isolation transformer.

[0068] The AC-DC rectifier bridge converts the input AC mains power (220V / 380V) into pulsating DC power, providing the DC power supply foundation for subsequent circuits. The input terminal of the AC-DC rectifier bridge is used to connect to the mains power, and the output terminal of the AC-DC rectifier bridge is connected to the input terminal of the DC-DC converter via a filter capacitor.

[0069] Two filter capacitors can be used, namely C1 and C2. C1 is a high-frequency filter capacitor to filter out high-frequency ripple after rectification; C2 is a low-frequency filter capacitor to smooth the DC voltage and ensure the stability of the voltage input to the DC-DC converter.

[0070] The DC-DC converter employs a phase-shifted full-bridge topology, converting the rectified and filtered DC voltage into an adjustable DC voltage suitable for battery charging. The output voltage and current are regulated by a control circuit. The output of the DC-DC converter is connected to the input of the isolation transformer, and the driver of the DC-DC converter is connected to the output of the control circuit.

[0071] The output terminal of the isolation transformer is connected to the first terminal of the primary winding. The isolation transformer is used to achieve electrical isolation between the main charging circuit and the battery pack, improving system safety, and also matches the charging voltage requirements through its turns ratio design. Specifically, the first terminals of the primary windings of each magnetic coupling transformer can be connected in parallel to form a common input terminal, and the output terminal of the isolation transformer can be connected to this common input terminal to supply power to the magnetic coupling transformer group.

[0072] In this embodiment, the first, second, and third operational amplifier units are all implemented using operational amplifiers, and are used for current sampling signal amplification, battery pack voltage sampling amplification, and magnetic coupling compensation voltage sampling amplification, respectively. Each operational amplifier includes a non-inverting input, an inverting input, and an output.

[0073] The operational amplifier corresponding to the first operational amplifier unit has its non-inverting input connected to the high potential terminal of the current sampling circuit, i.e., the negative terminal of the UPS battery pack; its inverting input connected to the low potential terminal of the current sampling circuit, i.e., the common negative terminal; and its output connected to the control circuit to transmit the amplified current sampling signal.

[0074] The operational amplifier corresponding to the second operational amplifier unit has its non-inverting input connected to the positive terminal of the multiple UPS battery packs through a resistor voltage divider network, and its inverting input connected to the negative terminal and output terminal of the UPS battery packs respectively. It is grounded through a zero-adjustment resistor (calibrating the zero point) to form a differential amplifier circuit, and its output terminal is connected to the control circuit to transmit the amplified voltage across the battery packs.

[0075] The operational amplifier corresponding to the third operational amplifier unit has its non-inverting and inverting input terminals connected to the voltage detection node set in the secondary reverse series circuit of the magnetic coupling current sharing circuit. At the same time, its inverting input terminal is connected to the output terminal to realize differential amplification of the signal. The output terminal is connected to the control circuit to transmit the amplified magnetic coupling compensation voltage.

[0076] Based on the circuit structure in the above embodiments, during the normal charging phase: the AC-DC rectifier bridge converts alternating current into direct current, which is then processed by a filter capacitor and fed into the DC-DC converter. Under the control of the control circuit, the DC-DC converter outputs a stable voltage, which charges each battery pack through a magnetically coupled current-sharing circuit. At this time, the current-sharing inductor works in conjunction with the magnetically coupled transformer. If the current of a certain battery pack is too high, the induced voltage in the primary winding of the corresponding magnetically coupled transformer increases, and the secondary winding generates a reverse compensation current, suppressing the current increase in that pack. Simultaneously, it causes other battery packs with lower currents to increase their current, thus achieving current sharing during charging.

[0077] Specifically, the feedback regulation logic of the control circuit is as follows: the current sampling unit detects the current of each UPS battery group in real time; the first, second, and third operational amplifier units respectively collect relevant voltage signals and send the current and voltage signals to the control circuit. The control circuit outputs a corresponding PWM signal based on the actual sampled current, and changes the output current and voltage of the DC-DC converter by adjusting the duty cycle of the PWM signal. At the same time, it controls the controllable MOSFET to adjust the compensation strength of the magnetic coupling module, forming a closed-loop regulation to ensure that the current difference between each group is controlled within 5%.

[0078] Example 2: Based on Example 1 above, referring to... Figure 5 As shown, the control circuit in this embodiment includes a microcontroller (MCU), an analog-to-digital converter, and a driver circuit. Among them,

[0079] The input terminals of the analog-to-digital converter (ADC) are connected to the output terminals of the current sampling circuit, the first operational amplifier unit, the second operational amplifier unit, and the third operational amplifier unit, respectively. The output terminal of the ADC is connected to the input terminal of the microcontroller. The ADC is used to convert the sampled current and voltage signals into digital signals and provide them to the microcontroller.

[0080] The output of the microcontroller is connected to the drive terminal of the DC-DC converter and the drive terminal of the controllable impedance unit via a drive circuit.

[0081] The drive circuit mainly amplifies the PWM signal and regulation signal output by the microcontroller to drive the DC-DC converter, thereby achieving precise regulation of the converter's output voltage and current. It also drives the secondary winding of the magnetic coupling transformer, changing the equivalent impedance of the secondary reverse series circuit in the magnetic coupling transformer, which in turn indirectly affects the induced electromotive force of the primary winding, thus achieving active current sharing compensation.

[0082] In this embodiment, the parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing also includes an overvoltage detection circuit, an overcurrent detection circuit, and a relay; wherein...

[0083] The input terminal of the overvoltage detection circuit is connected to the output terminal of the third operational amplifier unit, and the output terminal of the overvoltage detection circuit is connected to the input terminal of the microcontroller and the control terminal of the relay respectively.

[0084] The input terminal of the overcurrent detection circuit is connected to the common negative terminal of multiple UPS battery packs, and the output terminal of the overcurrent detection circuit is connected to the input terminal of the microcontroller and the control terminal of the relay respectively.

[0085] The output of the microcontroller is connected to the control terminal of the relay, and the contacts of the relay are connected to the input of the main charging circuit.

[0086] When overvoltage, overcurrent, or short circuit abnormalities are detected by the overvoltage and overcurrent detection circuits, trigger signals are output to the microcontroller and relay. The relay disconnects the main charging circuit, and the microcontroller simultaneously issues a corresponding alarm signal. Furthermore, the relay is controlled by both the overvoltage detection circuit and the filtering detection circuit, as well as the microcontroller, ensuring reliable operation even if a single protection path fails, thus enhancing safety.

[0087] Specifically, the microcontroller can use STM32 series chips to receive current and voltage data transmitted from the analog-to-digital converter, calculate compensation amounts using built-in current sharing algorithms (such as the downslope method and master-slave current sharing method), and output PWM signals to control the DC-DC converter and magnetic coupling transformer group. Alternatively, the microcontroller can directly use existing chips with current sharing functionality, such as the MSP430 series microcontroller and the N32G031F8S7 microcontroller.

[0088] In this embodiment, refer to Figure 6 As shown, the current sampling circuit includes multiple branch sampling resistors and a total current sampling resistor; among them,

[0089] The first terminal of the branch sampling resistor is connected to the negative terminal of the UPS battery pack, and the second terminal is connected to the common negative terminal of multiple UPS battery packs. The branch sampling resistors are denoted by R1 to Rn, where n is the number of UPS battery packs. The total current sampling resistor is denoted by Rtotal. For example, the current flow through the branch sampling resistors is: UPS battery pack negative terminal → R → common negative terminal. In the charging circuit of each UPS battery pack, a branch sampling resistor is connected in series, allowing the current in the corresponding charging circuit to be sampled.

[0090] The input terminals of the first operational amplifier unit are connected to the first and second terminals of the branch sampling resistors, respectively. At this time, the first operational amplifier unit can obtain the current flowing through the branch sampling resistor by collecting the voltage across each branch sampling resistor and combining it with the resistance value of the branch sampling resistor, thus realizing current sampling.

[0091] The first terminal of the total current sampling resistor is connected to the common negative terminal of the multiple UPS battery packs, and the second terminal is connected to the negative output terminal of the main charging circuit. When the negative terminals of all UPS battery packs converge, the current flows through the total current sampling resistor to the output negative terminal of the main charging circuit, forming a complete charging loop. At this time, the overcurrent detection circuit is connected to the common negative terminal of the multiple UPS battery packs, i.e., the high-potential terminal of the total current sampling resistor, and can detect the total charging current of the current multiple UPS battery packs.

[0092] In this embodiment, based on the above circuit structure, referring to... Figure 7As shown, the first operational amplifier unit in this embodiment includes a first analog switch, a second analog switch, and a differential amplifier; wherein, the input channel of the first analog switch is connected to the first terminal of a plurality of branch sampling resistors, and the input channel of the second analog switch is connected to the second terminal of a plurality of branch sampling resistors.

[0093] The common output terminal of the first analog switch and the common output terminal of the second analog switch are respectively connected to the input terminal of the differential amplifier, and the output terminal of the differential amplifier is connected to the input terminal of the microcontroller.

[0094] The enable terminals of the first analog switch and the second analog switch are respectively connected to the output terminals of the microcontroller.

[0095] Specifically, the number of input channels of the first analog switch and the second analog switch are the same as the number of UPS battery packs, meaning one input channel corresponds to one charging circuit. The microcontroller can switch different branch sampling resistors connected to the differential amplifier through the enable terminals of the first and second analog switches to perform current polling sampling of multiple UPS battery packs.

[0096] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing, applied to multiple UPS battery packs, characterized in that, include: The circuit includes a main charging circuit, a magnetically coupled current sharing circuit, a current sampling circuit, a first operational amplifier unit, a second operational amplifier unit, a third operational amplifier unit, and a control circuit; among which, The multi-UPS battery pack is composed of multiple UPS battery packs connected in parallel, and the negative terminals of the multiple UPS battery packs are connected in parallel to form the common negative terminal of the multi-UPS battery pack. The input terminal of the main charging circuit is connected to the mains power, and the positive output terminal of the main charging circuit is connected to the positive terminal of the multi-UPS battery pack via the first winding port of the magnetic coupling current sharing circuit. The common negative terminal of the multi-UPS battery pack is connected to the negative output terminal of the main charging circuit via the current sampling circuit. The input terminal of the first operational amplifier unit is connected to both ends of the current sampling circuit, and the output terminal of the first operational amplifier unit is connected to the input terminal of the control circuit. The input terminal of the second operational amplifier unit is connected to the positive and negative terminals of the multi-UPS battery pack, and the output terminal of the second operational amplifier unit is connected to the input terminal of the control circuit. The input terminal of the third operational amplifier unit is connected to the voltage detection node of the second winding port of the magnetically coupled current sharing circuit, and the output terminal of the third operational amplifier unit is connected to the input terminal of the control circuit. The output terminal of the current sampling circuit is connected to the input terminal of the control circuit, and the output terminal of the control circuit is connected to the driving terminal of the main charging circuit and the adjustment node of the second winding port.

2. The parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing according to claim 1, characterized in that, The magnetically coupled current-sharing circuit includes a magnetically coupled transformer group, a current-sharing inductor, a freewheeling diode, and a controllable impedance unit; wherein... The magnetic coupling transformer group includes multiple magnetic coupling transformers, each of which consists of a primary winding and a secondary winding with a common magnetic core. The first end of the primary winding is connected to the positive output terminal of the main charging circuit, and the second end of the primary winding is connected to the positive terminal of each UPS battery pack via a current sharing inductor. The freewheeling diode is connected in reverse parallel to the first and second ends of the primary winding; The output terminals of adjacent secondary windings are connected in reverse series to form a secondary reverse series circuit. A controllable impedance unit is connected in series in the secondary reverse series circuit. The driving terminal of the controllable impedance unit is connected to the output terminal of the control circuit. The secondary reverse series circuit is equipped with a voltage detection node, which is connected to the input terminal of the third operational amplifier unit.

3. The parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing according to claim 1, characterized in that, The main charging circuit includes an AC-DC rectifier bridge, a filter capacitor, a DC-DC converter, and an isolation transformer; The input terminal of the AC-DC rectifier bridge is used to connect to the mains power, and the output terminal of the AC-DC rectifier bridge is connected to the input terminal of the DC-DC converter via a filter capacitor. The output terminal of the DC-DC converter is connected to the input terminal of the isolation transformer, and the drive terminal of the DC-DC converter is connected to the output terminal of the control circuit. The output terminal of the isolation transformer is connected to the first terminal of the primary winding.

4. The parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing according to claim 1, characterized in that, The control circuit includes a microcontroller, an analog-to-digital converter, and a drive circuit; wherein... The input terminals of the analog-to-digital converter are connected to the output terminals of the current sampling circuit, the first operational amplifier unit, the second operational amplifier unit, and the third operational amplifier unit, respectively. The output terminal of the analog-to-digital converter is connected to the input terminal of the microcontroller. The output of the microcontroller is connected to the drive terminal of the DC-DC converter and the drive terminal of the controllable impedance unit via a drive circuit.

5. The parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing according to claim 4, characterized in that, It also includes overvoltage detection circuitry, overcurrent detection circuitry, and relays; among which, The input terminal of the overvoltage detection circuit is connected to the output terminal of the third operational amplifier unit, and the output terminal of the overvoltage detection circuit is connected to the input terminal of the microcontroller and the control terminal of the relay, respectively. The input terminal of the overcurrent detection circuit is connected to the common negative terminal of the multiple UPS battery packs, and the output terminal of the overcurrent detection circuit is connected to the input terminal of the microcontroller and the control terminal of the relay respectively. The output terminal of the microcontroller is connected to the control terminal of the relay, and the contact terminal of the relay is connected to the input terminal of the main charging circuit.

6. The parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing according to claim 1, characterized in that, The current sampling circuit includes multiple branch sampling resistors and a total current sampling resistor; wherein... The first end of the branch sampling resistor is connected to the negative terminal of the UPS battery pack, and the second end of the branch sampling resistor is connected to the common negative terminal of multiple UPS battery packs. The input terminals of the first operational amplifier unit are respectively connected to the first and second terminals of the branch sampling resistor; The first end of the total current sampling resistor is connected to the common negative terminal of the multiple UPS battery packs, and the second end of the total current sampling resistor is connected to the negative output terminal of the main charging circuit.

7. The parallel charging circuit for multiple UPS battery packs based on magnetic coupling current sharing according to claim 6, characterized in that, The first operational amplifier unit includes a first analog switch, a second analog switch, and a differential amplifier; wherein, the input channels of the first analog switch are respectively connected to the first terminals of multiple branch sampling resistors, and the input channels of the second analog switch are respectively connected to the second terminals of multiple branch sampling resistors; The common output terminal of the first analog switch and the common output terminal of the second analog switch are respectively connected to the input terminal of the differential amplifier, and the output terminal of the differential amplifier is connected to the input terminal of the microcontroller. The enable terminals of the first analog switch and the second analog switch are respectively connected to the output terminals of the microcontroller.

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