CN215452547U

CN215452547U - Online storage battery uniform charging and monitoring device

Info

Publication number: CN215452547U
Application number: CN202121785749.3U
Authority: CN
Inventors: 张军
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-08-03
Filing date: 2021-08-03
Publication date: 2022-01-07
Anticipated expiration: 2031-08-03

Abstract

The utility model discloses an online storage battery uniform charging and monitoring device, which comprises a power supply management module, a discharge detection module, a reactive load module and a DSP microcontroller, wherein the power supply management module is connected with the discharge detection module; the power management module is connected in series with the direct current end of the UPS rectification and is used for boosting the direct current; the discharge detection module is connected in parallel with two ends of each battery in the storage battery pack and is used for balancing the voltage of each battery in the storage battery pack; the reactive load module is connected in series with the tail end of the storage battery pack and is used for buffering and storing extra voltage; the DSP microcontroller is connected to the power management module and the leakage detection module and is used for controlling the boost PWM driving signal of the power management module and the switching tube driving signal of the leakage detection module. The utility model can perform real-time on-line monitoring on the single batteries connected in the battery pack in series and realize constant-voltage uniform charging of the single batteries under the condition of not influencing the normal work of the UPS, thereby improving the efficiency and reliability of the system, prolonging the service life of the batteries and having higher economic benefit.

Description

Online storage battery uniform charging and monitoring device

Technical Field

The utility model relates to the technical field of storage battery fault monitoring, in particular to an online storage battery uniform charging and monitoring device.

Background

With the rapid development of information digitization, storage batteries are being widely used in devices in the fields of base stations, data centers, electric power, and the like. As the most important hardware component of these emergency devices, the reliability thereof directly affects the service life and safety of the devices. Research and practice have shown that the life of the entire battery pack is far less than the life of a single cell. The most important reason is that the single batteries connected in the battery pack in series are not balanced. In the cyclic charging process, due to the difference of chemical components of individual batteries and the difference of operation histories, the inconsistency of the storage batteries is continuously expanded, so that the terminal voltages of the storage batteries are different under the same charging and discharging condition. While battery monitoring systems are directed to battery parameter differences within a small range, they typically do not alarm until the battery deteriorates.

In practical application, the battery is divided into floating charge and uniform charge: before the capacity of the storage battery is reduced to a specified value, the storage battery is charged uniformly and also becomes activated; the normal maintenance application process in the case of its normal maintenance, i.e. already fully charged, is called float charging. Generally, the battery pack normally operates in a float state. Taking a 12V/100AH battery as an example, the ideal float charge voltage is generally 13.2-13.8V, and if the voltage is higher than 14.5V, the battery can be in a uniform charge activated state for a long time, and the service life of the battery is greatly shortened and even the battery is scrapped. If the float voltage is lower than 10.5V, the storage battery is deeply discharged, and the current flowing through the storage battery is too large, so that the normal operation of the whole battery pack is influenced. In fig. 1, 4 batteries connected in series in the circuit are in a floating state, and the terminal voltage of each battery is ideally 13.5V. If the B2 battery is abnormal, and the measured terminal voltage is 12V, V1= V3= V4=14V, which is 13.8V higher than the set standard float charge voltage. If the battery pack is not subjected to a rapid recovery process for up to 1 year, B1, B3, and B4 will also decay rapidly until the entire battery pack fails. In practical high power applications, as many as 30 to 100 batteries are typically connected in series, and if one of them is problematic, the other batteries will also weaken chronically, causing significant economic losses. Therefore, the uniformity of the unit cells is very important for the life of the entire battery pack.

The overall constant voltage charging method is a method in which a plurality of storage batteries are connected in series in a power supply to perform centralized uniform charging. For example, a 12V battery is used, and the average charging voltage is 14.5V, the power supply provides N times of 14.5V voltage to supply power to the series-connected battery pack. But the method has simple structure, short time consumption and cost saving. However, the method avoids that the terminal voltage of the battery can not reach an ideal set value due to the difference of individual batteries, and the uniform charging effect is not ideal.

The equalizing voltage charging method is based on the integral constant voltage equalizing charging method and utilizes the switching characteristic of semiconductor element to manage the independent power source of single battery. There are also disadvantages for small batteries: the bypass of each battery needs to be connected with a bleeder circuit and a monitoring circuit in parallel, and for the application occasions with more batteries, the battery occupies more components. Damage to any of the components may cause the circuit to fail. Therefore, for the devices in the design, strict screening should be performed to ensure the quality. In addition, in high-power application occasions, the cost occupied by the capacitance dummy load of the circuit is also large.

The application is limited to offline charging, and the UPS systems on the market do not integrate a battery equalizing module or have an equalizing function, but cannot ensure that each storage battery is equalized.

SUMMERY OF THE UTILITY MODEL

In view of the above problems, an object of the present invention is to provide an online battery equalizing and monitoring device, which can solve the difficult problem of maintaining the regular equalizing charge of a lead-acid battery, and can perform real-time online monitoring on the single batteries connected in a battery pack and realize the constant-voltage equalizing charge of the single batteries without affecting the normal operation of a UPS, so as to improve the system efficiency and reliability, prolong the service life of the battery, and achieve high economic benefits. The technical scheme is as follows:

an online storage battery uniform charging and monitoring device comprises a UPS circuit, a power supply management module, a discharge detection module, a reactive load module and a DSP microcontroller;

the UPS circuit comprises a UPS, an inverter and a storage battery pack connected in series to the direct current side of the inverter;

the input end of the power management module is connected in series with the direct current end of the UPS rectifier and is used for boosting the direct current, and the output end of the power management module is connected to the anode of the storage battery pack;

the discharge detection module is connected in parallel with two ends of each battery in the storage battery pack and is used for balancing the voltage of each battery in the storage battery pack;

the reactive load module is connected in series with the tail end of the storage battery pack and is used for buffering and storing extra voltage;

the DSP microcontroller is connected to the power management module and the leakage detection module and is used for controlling a boost PWM driving signal of the power management module and a switch tube driving signal of the leakage detection module.

Furthermore, the power management module is realized by adopting a BOOST circuit, and the topological structure of the BOOST circuit comprises an inductor L, a diode D and an IGBT; one end of the inductor L is connected with the anode of the input end Vin, the other end of the inductor L is simultaneously connected with the C pole of the IGBT and the anode of the diode D, and the E pole of the IGBT is grounded; the cathode of the diode D is connected to the output terminal Vout.

Furthermore, the leakage detection module comprises a driving IC, a battery bypass MOSFET, a divider resistor and a differential amplification circuit; after the voltage of the battery terminal is divided by a divider resistor, the voltage enters a differential amplification circuit and is output to an ADC unit of the DSP microcontroller; the DSP microcontroller controls the battery bypass MOSFET to perform switching action through the drive IC.

Compared with the prior art, the utility model has the beneficial effects that: the utility model realizes the on-line constant-voltage charging and monitoring of the lead-acid storage battery monomer, and mainly aims to solve the problem of difficulty in maintaining the lead-acid storage battery at regular intervals; under the condition that the normal work of the UPS is not influenced, the single batteries connected in series in the battery pack can be monitored in real time on line, and the constant voltage uniform charging of the single batteries is realized, so that the efficiency and the reliability of the system are improved, the service life of the batteries is prolonged, and the UPS battery pack has higher economic benefit.

Drawings

Fig. 1 is a schematic diagram of charging a series battery pack.

Fig. 2 is a schematic structural diagram of an online storage battery charging and monitoring device according to the present invention.

Fig. 3 is a topological structure diagram of the power management module of the utility model.

Fig. 4 is a topological structure diagram of the middle driving bleeder circuit of the utility model.

Fig. 5 is a diagram of the internal execution structure of the DSP microcontroller in the utility model.

Fig. 6 is a schematic diagram of the current flow when the MOSFET is turned on or off.

FIG. 7 is a diagram comparing the charging states of a conventional UPS structure and a UPS structure incorporating battery equalizing charge; (a) a common UPS configuration; (b) and adding a battery equalizing charge UPS structure.

FIG. 8 is a variation process of the UPS converting from floating charge to equalizing charge battery terminal voltage; (a) an ideal cell end voltage diagram; (b) and the voltage equalizing circuit is used for actually pressing the battery end.

Detailed Description

The utility model is described in further detail below with reference to the figures and specific embodiments.

The utility model adds a battery management constant voltage uniform charging module on the basis of the existing UPS. The structure of the on-line storage battery uniform charging and monitoring device is shown in figure 2 and comprises a UPS circuit, a power supply management module, a discharge detection module, a reactive load module and a DSP microcontroller.

The UPS circuit comprises a UPS, an inverter and a storage battery pack connected in series on the direct current side of the inverter.

The input end of the power management module is connected in series with the direct current end of the UPS rectification for boosting the direct current, and the output end of the power management module is connected to the anode of the storage battery pack. The BOOST circuit can be used for realizing. If the battery is in the floating charge state, the output and the input of the battery are the same; when the battery needs to be balanced and quickly charged, the battery outputs the voltage needed by the battery pack.

The topology structure diagram of the BOOST circuit is shown in fig. 3, and comprises an inductor L, a diode D and an IGBT; one end of the inductor L is connected with the anode of the input end Vin, the other end of the inductor L is simultaneously connected with the C pole of the IGBT and the anode of the diode D, the E pole of the IGBT is grounded, and the cathode of the diode D is connected to the output end Vout.

Vout is the output and Vout and Vin are equal when the battery is in a float state, i.e. the IGBT in fig. 3 is not conducting. When the battery needs to be charged uniformly and quickly, the DSP is required to control the drive signal of the IGBT, so that the output Vout reaches the set total value of the charging voltage of the storage battery. For example, if the storage battery has 30 batteries, each battery has 12V, the average charging voltage is 14.5V, and then the Vout needs 435V.

The discharge detection module is connected in parallel with two ends of each battery in the storage battery pack and is used for balancing the voltage of each battery in the storage battery pack.

As shown in fig. 4, the leakage detection module includes a driving IC, a battery bypass MOSFET tube, a voltage dividing resistor, and a differential amplification circuit; after the voltage of the battery terminal is divided by a divider resistor, the voltage enters a differential amplification circuit and is output to an ADC unit of the DSP microcontroller; the DSP microcontroller controls the battery bypass MOSFET to perform switching action through the drive IC.

When the storage battery is in a balanced and fast charging state, the DSP controller starts to drive a switching tube of a battery bypass to perform constant voltage operation. The switching device usually uses MOSFET to deal with low-voltage and high-power occasions. After the voltage of the battery is divided by the resistors, the voltage enters the differential amplification circuit and outputs proper voltage to the ADC unit of the DSP, and after the voltage acquisition is finished, software can automatically judge whether to perform switching action on a bypass MOSFET of the battery. When the battery voltage is higher than a set value, the MOSFET is turned off and turned on; otherwise, the switch is closed. To reduce the error in the regulated voltage, the PWM drive carrier should be as high as possible, typically with a carrier frequency of 12K to 20K.

The reactive load module and the discharge detection module play a role simultaneously and are connected in series to the tail end of the storage battery pack for buffering and storing extra voltage.

The DSP microcontroller is connected to the power management module and the leakage detection module and is used for controlling a boost PWM driving signal of the power management module and a switch tube driving signal of the leakage detection module. The temperature, voltage, current acquisition and software protection of the battery are also integrated in the controller. The internal execution structure of the DSP is shown in fig. 5. For multiple batteries, the CPU needs to perform the sequential execution within the interrupt and then drive the timer to issue the PWM signal. The same approach can be used for dummy load capacitors. The only thing to be noted is that the charging and discharging time constant of the capacitor and the inductor needs to be carefully determined, otherwise, the charging current of the inductor is too large, which causes an overcurrent phenomenon.

The dotted arrow in fig. 6 is the current flow direction for charging the inductor after the MOSFET is turned on; the solid arrows indicate that the capacitor supplies energy to the battery pack load after shutdown.

And (3) feasibility analysis of a charging circuit: in the floating charge state of the ordinary UPS, the direct current bus side provides a calibrated floating charge voltage value. Fig. 7 (a) shows a conventional UPS structure, in which the battery is 12V, the float voltage of a single battery is 13.5V, and the dc bus voltage is fixed to 40.5V. If one battery has larger internal resistance, the terminal voltage of the battery is increased, and the other two batteries are reduced. In fig. 7 (b), in the improved UPS system with the battery equalization charging added, the voltage drop of the battery with high terminal voltage is controlled to be within the normal range, and the other two batteries will not be affected. The released extra energy will be stored in the capacitor in a reactive state and then supplied to the load for use.

The DSP microcontroller is always in a monitoring working state when the UPS is used, and when the storage battery needs to be uniformly charged, the booster circuit in the power management module raises the direct-current bus to a required value. And then the voltage-sharing control module starts to work, so that the problem of end voltage unbalance caused by individual battery difference is solved. Fig. 8 shows the variation process of the battery terminal voltage when the UPS changes from float charging to even charging, wherein (a) is an ideal battery terminal voltage diagram, and (b) is an actual battery terminal voltage diagram of the voltage equalizing circuit. PWM control can cause variations in the battery terminal voltage ripple, primarily due to its carrier frequency ripple, which is ignored and is within an acceptable range if the carrier frequency is sufficiently high.

Claims

1. An online storage battery uniform charging and monitoring device is characterized by comprising a UPS circuit, a power supply management module, a discharge detection module, a reactive load module and a DSP microcontroller;

2. The on-line battery uniform charging and monitoring device according to claim 1, wherein the power management module is implemented by a BOOST voltage BOOST circuit, and the topology structure of the BOOST voltage BOOST circuit comprises an inductor L, a diode D and an IGBT; one end of the inductor L is connected with the anode of the input end Vin, the other end of the inductor L is simultaneously connected with the C pole of the IGBT and the anode of the diode D, and the E pole of the IGBT is grounded; the cathode of the diode D is connected to the output terminal Vout.

3. The online storage battery equalizing-charging and monitoring device according to claim 1, wherein the bleed-off detection module comprises a driving IC, a battery bypass MOSFET tube, a voltage dividing resistor and a differential amplification circuit; after the voltage of the battery terminal is divided by a divider resistor, the voltage enters a differential amplification circuit and is output to an ADC unit of the DSP microcontroller; the DSP microcontroller controls the battery bypass MOSFET to perform switching action through the drive IC.