Controller for ensuring uninterruptible power supply of important load

Abstract

The utility model discloses a controller capable of ensuring uninterruptible power supply of an important load. The controller is used for providing an independent battery standby power service for important equipment in a communication base station. After the commercial power is cut off, a common battery supplies power to all loads including important loads in a machine room, when the common battery is about to be used up, the controller is switched to an important battery end, an important battery supplies power to the important loads, but the important battery does not supply power to other non-important loads, so that the backup power supply duration of the important loads is prolonged, and the standby power supply efficiency is improved. And special services are provided for operators. The controller can effectively solve the problem of abnormal power failure of the important load caused by various reasons, ensures continuous and reliable work of the important load, and is low in cost investment and low in operation and maintenance difficulty.

Description

Technical Field

[0001] The utility model relates to the field of power supply controllers, in particular to a controller which ensures that important loads are powered on continuously. Background Art

[0002] The OLT (broadband) services and seismic intensity meters of communication operators are classified as important loads and require a high level of backup power supply. At present, many base stations are connected to other non-important loads, which will cause the lithium battery power to be quickly consumed by other non-important loads; and if the DC bus is abnormal due to various reasons, the important load will lose power or shut down. In order to extend the backup power supply time of important loads and improve the reliability of power supply, the traditional approach is to configure more lithium batteries or configure a switching power supply system for important loads separately.

[0003] (1) Configure more lithium batteries to provide more power to extend the power supply time of important loads during power outages. Figure 1 , adding multiple conventional batteries is the most common solution currently used.

[0004] This solution requires an increase in the number of lithium batteries, which will bring more cost investment and operation and maintenance difficulties, especially in the current scenarios where lithium batteries are used in large quantities. The battery discharge curve is relatively flat, and it is difficult to accurately control the battery remaining power by controlling the primary power-off voltage. Most of the power will be consumed by non-important loads first, resulting in the failure to guarantee the backup power for important loads.

[0005] Battery performance also varies, making it difficult to evaluate the performance of each battery and to accurately set the power-down value of the switching power supply as needed.

[0006] If a fault occurs in the switching power supply system, such as an output short circuit in the power module that causes a bus short circuit, the remaining power modules and the lithium battery BMS will also trigger overcurrent protection shutdown. The bus power failure will cause important loads to lose power, and the important loads will not resume power until the operation and maintenance personnel complete on-site repairs. The power-off time of important loads will be very long.

[0007] (2) Configure a separate switch power supply system for important loads to separate important loads from other non-important loads so that the power of the lithium battery will not be consumed by other non-important loads, thus achieving separate backup power management for important loads. Figure 2 , this power system only has important loads.

[0008] This solution will add a switching power supply system, which will bring more cost investment and difficulty in operation and maintenance. It cannot eliminate the problem of bus power failure caused by power module failure. Important loads will lose power or shut down when the bus status is abnormal. Utility Model Content

[0009] In view of the problems existing in the above-mentioned background technology, a controller is proposed to ensure that important loads are not disconnected from power supply, which is used to provide a separate battery backup service for important equipment in a communication base station. After the city power outage, ordinary batteries power all loads in the machine room including important loads. When the ordinary batteries are about to run out of power, the controller switches to the important battery terminal, and the important batteries power the important loads. However, the important batteries will not power other non-important loads, so as to extend the backup power supply time of important loads and provide special services for operators. This controller can effectively solve the problem of abnormal power failure of important loads due to various reasons, ensure the continuous and reliable operation of important loads, reduce cost investment, and reduce operation and maintenance difficulty.

[0010] A controller for ensuring that important loads are not disconnected from power supply, comprising a first branch and a second branch connected in parallel, the first ends of the two branches are connected to a power supply system, the tail end of the first branch is connected to the important load, and the tail end of the second branch is connected to an important battery;

[0011] The first branch has a battery fuse and a diode No. ① connected in series; the tail ends of the first branch and the second branch are connected and a diode No. ③ is provided; the head end of the second branch is connected to the secondary power-off contactor of the original switch power supply system and a diode No. ② is connected in series;

[0012] In the first branch, a lead wire is drawn between the battery fuse and the diode to connect to a conventional battery;

[0013] Each device in the controller is equipped with a heat sink.

[0014] Furthermore, in the controller, diode No. 1 is connected in series between the battery fuse and the important battery, with the cathode connected to the battery fuse side and the anode connected to the important battery side; diode No. 2 is connected in series between the secondary power-off and the important load, with the cathode connected to the secondary power-off side and the anode connected to the important load side; the cathode of diode No. 3 is connected to the anode of diode No. 1, and the anode is connected to the anode of diode No. 2.

[0015] Furthermore, diode ① uses multiple high-power Schottky diodes connected in parallel, which are used for charging important batteries through the main bus and are cut off when the important batteries reversely discharge to the bus.

[0016] Furthermore, diode No. ② uses multiple high-power Schottky diodes connected in parallel and is used for the main bus to supply power to important loads.

[0017] Furthermore, MOS tubes are connected in parallel on both sides of diode ②.

[0018] Furthermore, the MOS tube selects NMOS with large current and low on-resistance, and is connected in parallel alone or in multiples. When the main bus supplies power to important loads, the MOS tube is closed; when the main bus is abnormal, the MOS tube is turned off.

[0019] Furthermore, diode No. ③ uses multiple diodes connected in series, and the number is selected according to actual needs, which is 1 to 8 diodes connected in series.

[0020] Furthermore, DC contactors are connected in parallel on both sides of diode ③.

[0021] Furthermore, diode ① is replaced by a plurality of MOS tubes or IGBTs connected in parallel.

[0022] Furthermore, the controller is equipped with an LCD screen, operation buttons, indicator lights and RS485 communication interface to complete the functions of system status monitoring, automatic switching of power supply, voltage and current collection and display; the collected information includes main bus voltage, important battery voltage, important load voltage, important battery current, important load current and equipment temperature; LED indicator lights include green power indicator light, yellow communication indicator light, and red alarm indicator light to alert users or maintenance personnel and prompt subsequent operations; users can remotely monitor the system operation status and data and set parameters through RS485 communication.

[0023] The beneficial effects achieved by the utility model are:

[0024] (1) The utility model can separate ordinary loads from important loads in the case of a set of switching power supply systems, thereby improving the power supply time and power supply reliability of important loads, with low cost investment and low operation and maintenance difficulty.

[0025] (2) The utility model solves a relatively common problem. When an output short-circuit fault occurs in a power module, the busbar is short-circuited. Other modules on the busbar and the lithium battery BMS trigger overcurrent protection and shut down, stopping power supply to important loads.

[0026] (3) The utility model can be adapted to the existing switching power supply system to realize independent backup power for important loads, does not rely on the system main controller, and has a wide range of application scenarios.

[0027] (4) The utility model is durable and stable in terms of both design and device selection, and has high reliability. Important loads are unlikely to lose power or shut down, thus improving the stability of power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the first solution in the background technology of the utility model.

[0029] Figure 2 It is a schematic diagram of the second solution in the background technology of the present utility model.

[0030] Figure 3 This is a schematic diagram of the first structure of the controller in the specific implementation mode of the utility model.

[0031] Figure 4 This is a second structural diagram of the controller in a specific implementation manner of the utility model. DETAILED DESCRIPTION

[0032] The technical solution of the utility model is further described in detail below in conjunction with the accompanying drawings of the specification.

[0033] This controller is used in DC power supply systems, where at least two lithium batteries are used as backup power supplies to power the equipment. Figure 3 The upper frame line is the utility model, and the lower frame line is the original 48V switching power supply system. You only need to change the wiring of the original power supply system and connect the utility model. One of the lithium batteries acts as a regular battery to supply power to all loads after the city power outage; the other lithium battery acts as an important battery to only supply power to important loads.

[0034] The controller is equipped with an LCD screen and operation buttons to complete system status monitoring, automatic power supply switching, voltage and current collection and display, etc. The specific information collected includes main bus voltage, important battery voltage, important load voltage, important battery current, important load current, etc. Figure 3 As shown, ⑥ to ⑪ are the collection points of voltage and current, the differential voltage between ⑦ and ⑥ is the main bus voltage, the differential voltage between ⑦ and ⑧ is the important battery voltage, the differential voltage between ⑦ and ⑨ is the important load voltage, ⑩ can choose to use a shunt or Hall element to collect the current of the important battery, and ⑪ can choose a shunt or Hall element to collect the current of the important load. The MCU of this controller uses N32G455CCL7, which does not require a very high single-chip microcomputer, and other 32 single-chip microcomputers can also be used. The MCU compares these collected information to determine the current state of the system. If the main bus voltage is too low and only 48V, it is considered that the main power has been cut off and the conventional battery of the main road is about to be discharged. At this time, it will switch to the important battery to supply power to the important load; after the main bus voltage rises to 55V, it is considered that the main power is coming and the important battery is also being charged. At this time, it will switch back to the main bus to supply power to the important load. The voltage and current information collected by the MCU and the judged system operation status will be displayed to the user through the LCD screen. The user can set parameters through the operation buttons. For example, the default setting is that when the main bus is detected to be lower than 48V, it is considered that the main power is out and the conventional battery is low, and it will immediately switch to the important battery to supply power to the important load. The setting of this parameter can be modified through the screen and buttons. For example, if it is changed to 50V, it means that when the main bus is detected to be lower than 50V, it is considered that the main power is out and the conventional battery is low, and it will immediately switch to the important battery to supply power to the important load. This controller can display the system operation status in real time through the LCD screen, and set the key judgment parameters for automatically switching to the important battery power supply or the main bus power supply. It has high real-time performance, is intelligent and convenient, and is easy to operate.

[0035] Since diodes and MOS tubes will pass large currents for a long time, the temperature rise of the devices must be considered. Devices ①, ②, ③, and ④ need to be equipped with a heat sink with good heat dissipation performance, and add a fan to assist in heat dissipation. Add an NTC resistor to the heat sink to collect the temperature of the heat sink and then control the speed of the fan. If the temperature is getting higher and higher, gradually increase the duty cycle of the fan and increase the fan speed to help dissipate heat.

[0036] System operating conditions and functional logic:

[0037] 1. The mains is normal, and the switching power supply (main bus) supplies power to common loads and important loads. At this time, MOS tube No. ④ is closed to reduce the voltage drop and loss caused by the diode.

[0038] 2. When the city power fails, the conventional battery (main bus) supplies power to the common loads and important loads. At this time, MOS tube No. ④ is closed to reduce the voltage drop and loss caused by the diode.

[0039] 3. When the utility power fails, when the conventional battery is discharged to 49V (48 to 50V can be set), the system switches from the main bus power supply to the important battery power supply. At this time, the ④ MOS tube is disconnected and the ⑤ contactor is closed. At this time, the important load is powered by the important battery. Due to the presence of the ② diode, the important battery will not discharge to the ordinary load.

[0040] 4. After the mains power comes in, it is detected that the main bus voltage is higher than 52.5V, and the main bus is switched to supply power to important loads and charge all batteries at the same time. At this time, MOS tube No. ④ is closed, contactor No. ⑤ is disconnected, and the main bus supplies power to important loads.

[0041] 5. In case of abnormal power failure of the main busbar, such as manual secondary power-off, the important load will not lose power or shut down due to the freewheeling of diode ③. At this time, MOS tube ④ will be quickly turned off, contactor ⑤ will be closed, and the important load will be switched to the important battery to supply power.

[0042] 6. In the event of an instantaneous or long-term short circuit on the main bus, such as accidental contact of an external cable or a power module failure, MOS tube No. 4 will be quickly turned off. Due to the reverse cutoff of diodes No. 1 and No. 2, the important battery will not discharge reversely to the bus, and the important battery will not trigger the overcurrent protection. Then contactor No. 5 will be closed and switched to the important battery to supply power to the important load.

[0043] Device function and selection description:

[0044] Diode ① is used to charge important batteries from the main bus. It is cut off when the important batteries reversely discharge the bus, ensuring that the important batteries only supply power to important loads. It is recommended to use multiple high-power Schottky diodes in parallel. Schottky diodes have low voltage drop and low loss, which is convenient for battery charge and discharge management.

[0045] Diode ② uses the same high-power Schottky diode as ①, and is used to supply power to important loads from the main bus. Although MOS tube ④ will be closed when the main bus is powered, this controller uses multiple high-power Schottky diodes in parallel. In the event of a single fault, if the controller fails to close MOS tube ④, diode ② can also be used to supply power to important loads from the main bus.

[0046] MOS tube No. ④ selects NMOS with large current and low on-resistance. When the main bus supplies power to important loads, this MOS tube is closed to reduce the voltage drop and loss caused by diode No. ②. When the main bus is abnormal, such as power failure or short circuit, due to the extremely fast switching characteristics of MOS, this MOS tube is quickly turned off to avoid the important battery from forming a short circuit with the main bus through this MOS tube, triggering the overcurrent protection of the important battery and shutting down, causing the important load to lose power.

[0047] Diode No. ③ can be an ordinary high-power diode. There are 5 diodes connected in series. For example, the voltage drop of each diode is 0.8V, and the total voltage drop is 4V. The function is that when the main power supply is supplied, due to the existence of 4V voltage difference, the important load will not obtain power from the important battery. In the process of No. ④ MOS tube being cut off and No. ⑤ contactor being closed, it provides reliable freewheeling for the important load.

[0048] Contactor No. ⑤ selects a DC contactor. When switching to important batteries to power important loads, close this contactor to prevent diode No. ③ from being damaged by heat due to excessive loss.

[0049] The circuit part of this controller ( Figure 3 In the upper middle frame), diodes ① and ② can be several diodes or rectifier bridges connected in parallel, and other switching devices such as MOS, IGBT, contactors, etc. can also be added in parallel; diode ③ does not necessarily mean 5 diodes in series, but can also be several diodes or rectifier bridges connected in series and parallel; bypass contactor ⑤ can also be MOS, IGBT, etc. other devices; MOS tube ④ can be deleted or replaced with other devices such as IGBT, contactors, etc.

[0050] This controller mainly uses the reverse cutoff characteristics of the diode to separate the common load from the important load. Figure 4 The part inside the upper frame is the core idea of ​​this controller, and the circuit derived from this idea is also the key circuit that needs to be protected. Figure 4 The circuit derived inside the upper frame is flexible and changeable, and can be composed of only three diodes: diode No. 1 is connected in series between the battery fuse and the lithium battery, with the cathode connected to the battery fuse side and the anode connected to the lithium battery side; diode No. 2 is connected in series between the secondary power down and the important load, with the cathode connected to the secondary power down side and the anode connected to the important load side; the cathode of diode No. 3 is connected to the anode of diode No. 1, and the anode of diode No. 3 is connected to the anode of diode No. 2. Figure 4 Any diode in the circuit can be connected in parallel with several diodes or rectifier bridges, or replaced with other switching devices such as MOS, IGBT, contactor, etc.; switching devices such as MOS, IGBT, contactor, etc. can also be added in parallel at any diode. For example, diode No. ① can be connected in parallel with several diodes, or replaced with several MOS tubes or IGBTs in parallel. Figure 4 The circuit derived from the idea is also a key part that needs to be protected.

[0051] This controller collects information such as main bus voltage, important battery voltage, important load voltage, important battery current, important load current, etc., to determine different system states such as main power incoming / main power outage / conventional battery about to be discharged, and then switches the main bus power supply or the important battery power supply.

[0052] This controller uses an LCD screen and buttons to realize independent backup power for important loads, which can be completed without relying on the main controller of the 48V power system. RS485, CAN or other communication methods can also be used to make this controller a functional component of the power system, and the functions of this controller can be realized through the main controller of the power system. Both implementation methods require protection.

[0053] For the heat dissipation of diodes, MOS tubes and other devices in the circuit, the heat sink used can be one or more; a heat sink can be equipped with only one device or multiple devices; it can be equipped with fans, air conditioners, etc. to assist in heat dissipation, or it may not be equipped with them.

[0054] The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiment. Any equivalent modifications or changes made by ordinary technicians in this field based on the contents disclosed in the present invention should be included in the protection scope recorded in the claims.

Claims

1. A controller that ensures that important loads are not powered off, characterized by: The controller comprises a first branch and a second branch connected in parallel, the head ends of the two branches are connected to the power supply system, the tail end of the first branch is connected to an important load, and the tail end of the second branch is connected to an important battery; The first branch has a battery fuse and a diode No. ① connected in series; the tail ends of the first branch and the second branch are connected and a diode No. ③ is provided; the head end of the second branch is connected to the secondary power-off contactor of the original switch power supply system and a diode No. ② is connected in series; In the first branch, a lead wire is drawn between the battery fuse and the diode to connect to a conventional battery; Each device in the controller is equipped with a heat sink.

2. A controller for ensuring that important loads are powered on continuously according to claim 1, characterized in that: In the controller, diode No. 1 is connected in series between the battery fuse and the important battery, with the cathode connected to the battery fuse side and the anode connected to the important battery side; diode No. 2 is connected in series between the secondary power-off and the important load, with the cathode connected to the secondary power-off side and the anode connected to the important load side; the cathode of diode No. 3 is connected to the anode of diode No. 1, and the anode is connected to the anode of diode No.

2.

3. A controller for ensuring that important loads are powered on continuously according to claim 1, characterized in that: Diode ① uses multiple high-power Schottky diodes connected in parallel, which are used to charge important batteries from the main bus and are cut off when the important batteries reversely discharge to the bus.

4. A controller for ensuring that important loads are powered on continuously according to claim 1, characterized in that: Diode No. ② uses multiple high-power Schottky diodes connected in parallel and is used for the main bus to supply power to important loads.

5. A controller for ensuring uninterrupted power supply to important loads according to claim 1, characterized in that: MOS tubes are connected in parallel on both sides of diode ②.

6. A controller for ensuring that important loads are powered on continuously according to claim 5, characterized in that: The MOS tube selects NMOS with large current and low on-resistance, and is connected in parallel either individually or in multiples. When the main bus supplies power to important loads, this MOS tube is closed; when the main bus is abnormal, this MOS tube is turned off.

7. A controller for ensuring uninterrupted power supply to important loads according to claim 1, characterized in that: Diode No. ③ uses multiple diodes connected in series, and the number is selected according to actual needs, which is 1 to 8 diodes connected in series.

8. The controller for ensuring that important loads are powered on continuously according to claim 1, characterized in that: A DC contactor is connected in parallel on both sides of diode ③.

9. The controller for ensuring uninterrupted power supply to important loads according to claim 1, characterized in that: Diode ① is replaced by several MOS tubes or IGBTs connected in parallel.

10. The controller for ensuring uninterrupted power supply to important loads according to claim 1, characterized in that: The controller is equipped with an LCD screen, operation buttons, indicator lights and RS485 communication interface to complete the functions of system status monitoring, automatic switching of power supply, voltage and current collection and display; the collected information includes main bus voltage, important battery voltage, important load voltage, important battery current, important load current and equipment temperature; LED indicator lights include green power indicator light, yellow communication indicator light and red alarm indicator light to remind users or maintenance personnel to pay attention and prompt subsequent operations; users can remotely monitor the system operation status and data and set parameters through RS485 communication.

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