Control system and control method for supercapacitor large-current discharge

Abstract

The present application relates to the technical field of load control, and particularly relates to a control system for super capacitor large-current discharge, which comprises: a battery module, a super capacitor module, an electric device and a standby switching feedback source, the battery module provides electric energy for the super capacitor module, the super capacitor module stores electric energy and provides large-current discharge for the electric device, an input current sensor is installed on a circuit connected between the battery module and the super capacitor module, a feedback current sensor is installed on a circuit connected between the battery module and the electric device, the standby switching feedback source comprises a CPU and a variable resistor, the input current sensor and the feedback current sensor are connected with input ends of the CPU respectively, and the variable resistor is connected with a control end of the CPU. The system and method provided by the present application can effectively control the difficult-to-control large-current discharge output and greatly improve the safety.

Description

Technical Field

[0001] This invention relates to the field of load control technology, and in particular to a control system and control method for high-current discharge of supercapacitors. Background Technology

[0002] Supercapacitors are a relatively new type of energy storage and discharge capacitor in the industrial field. Their advantages include:

[0003] 1. Fast charging speed: It can reach more than 95% of its rated capacity in just 10 seconds;

[0004] 2. Long cycle life: The number of deep charge and discharge cycles can reach 10,000 to 500,000 times, with no "memory effect" and no problem of over-discharge;

[0005] 3. It has strong high-current discharge capability, high energy conversion efficiency, low process loss, and high current energy cycle efficiency ≥90%. It has the advantages of long cycle life, fast charge and discharge rate, environmental protection, high power density, strong high-current discharge capability, and high safety.

[0006] Supercapacitors are often used in industry for high-current, short-time charging and discharging. Ordinary supercapacitors can reach 95% of their rated capacity within 10 seconds of charging current. At the same time, their low impedance results in high power output of 1000-2000W / KG. Their unique discharge output characteristics make them the only energy storage device among existing technological materials that can provide high-current discharge. However, their low energy density, high self-discharge rate, and uncontrollable discharge process limit their widespread industrial applications.

[0007] Lead-acid batteries and lithium batteries are relatively traditional energy storage batteries with high energy density. Traditional lithium batteries can achieve an energy density of 20-100 Wh / kg, and a suitable volume and weight can bring a large energy output. However, due to the limitations of current technology and materials, their power density is low and their short-term high-power output is poor, resulting in less than ideal high-current charging and discharging performance.

[0008] Current technologies often use batteries and supercapacitors connected in parallel as the power source, and their charging and discharging strategies are as follows: Figure 3 As shown.

[0009] The super capacitor module and the battery are connected in parallel from the internal structure to provide power output for the power equipment, so as to solve the problem that the voltage of the super capacitor gradually decreases during discharging. The super capacitor module and the battery module are connected in parallel as a backup power supply, the ESR is small, the power characteristics are good, the power density is much larger than that of the battery, the power compensation of the main power supply ensures the short-time and large-current power output, so that the overcharge or overdischarge of the whole module will not affect the electrical performance. The combination of the super capacitor and the battery as the discharging super capacitor can have the advantages of both, the different electrodes of the super capacitor and the battery are combined from the internal structure, the performance of the two energy storage modes is complementary, and the combination has the advantages of low cost, high energy density, long cycle service life, strong environmental adaptability and the like. However, the discharging speed of the super capacitor in the prior art is determined according to the load of the external equipment, and the load power and working current are large, so the discharging is fast,

[0010] The control process mainly follows the following formula:

[0011]

[0012] T=[C×(U work -U min )]

[0013] I 充 ×T 充 =C×dU work

[0014] C×dU work -I×C×(R 线 +R ESR )=I×T

[0015] Wherein, I is the load current, U work is the normal working voltage of the super capacitor, U min is the cutoff working voltage, R 线 is the total internal resistance of the external circuit, which is determined according to the properties, thickness and the like of the circuit material, R ESR is the equivalent series resistance; T is the continuous discharging time, C is the rated capacity of the capacitor, I 充 is the charging current, and T 充 is the charging time.

[0016] The prior art uses the super capacitor to discharge externally, and the discharging process is difficult to control. Due to external short circuit, the current discharging is too large, and the internal circuit is impacted, even fire and explosion accidents occur. SUMMARY

[0017] The technical problem to be solved by the present application is to provide a super capacitor large current discharge control system and method which can effectively control the difficult-to-control large current discharge output and greatly improve safety.

[0018] The present application is implemented by the following technical solutions:

[0019] The super capacitor large current discharge control system comprises a battery module, a super capacitor module, a power consuming device and a backup switching feedback source, the battery module provides electric energy for the super capacitor module, the super capacitor module stores electric energy and provides large current discharge for the power consuming device, an input current sensor is installed on the circuit connecting the battery module and the super capacitor module, a feedback current sensor is installed on the circuit connecting the battery module and the power consuming device, the backup switching feedback source comprises a CPU and a variable resistor, the input current sensor and the feedback current sensor are connected to the input end of the CPU respectively, the variable resistor is connected to the control end of the CPU, the CPU receives the input current signal and the feedback current signal sent by the input current sensor and the feedback current sensor and compares them, when the ratio between the feedback current and the input current exceeds the set range, the CPU controls the variable resistor to change the internal resistance value, so that the super capacitor discharge process forms a closed loop system, and the super capacitor large current discharge is continuously fed back and corrected.

[0020] The super capacitor large current discharge control method comprises the following steps:

[0021] The input current sensor transmits the input current of the super capacitor to the CPU of the backup switching feedback source, and the feedback current sensor transmits the feedback current of the super capacitor to the CPU of the backup switching feedback source.

[0022] The CPU of the backup switching feedback source receives the input current and the feedback current and compares them, when the ratio between the feedback current and the input current exceeds the set range, the CPU controls the variable resistor to change the internal resistance value, so that the super capacitor large current discharge is continuously fed back and corrected.

[0023] Further, the method for the CPU to control the variable resistor to change the internal resistance value and continuously feed back and correct the super capacitor large current discharge is as follows:

[0024] The battery provides output electric energy to the power consuming device through the front channel before the super capacitor supplies output electric energy to the power consuming device, and the output electric energy is fed back to the backup switching source control to form a feedback channel, and it can be concluded that:

[0025] E (s) = R (s) -B (s)

[0026] E (s) : deviation control signal

[0027] R (s) : battery discharge output

[0028] B (s) : sampling feedback signal

[0029] That is, the supplement of the battery pack to the super capacitor by the control loop is inputted and controlled by the standby switching source and the battery input, during the discharge process of the battery pack, the open loop transfer function of the switching control system can be obtained by Laplace transformation of the sampling feedback signal and the deviation control signal

[0030] The output signal and the deviation signal are Laplace transformed and compared to obtain the forward channel transfer function of the switching control system Therefore, for the negative feedback connection of the system, the negative feedback control is controlled according to C (s) = [R (s) -H (s) C (s) ]G (s) .

[0031] Advantages of the present application

[0032] By introducing the switching feedback control, the super capacitor discharge process constitutes a system closed loop, and the super capacitor large current discharge is continuously fed back and corrected.

[0033] After introducing the switching feedback, the system forms a negative feedback closed loop control, and the negative feedback can suppress the internal parameter change (including the nonlinear factors in the super capacitor discharge process) of the surrounded part and the disturbance acting on the input end, and effectively avoid the influence of high frequency noise.

[0034] By the switching control strategy, the difficulty of super capacitor output control, large current discharge output control, is solved, and the problem of unreliable instantaneous control of emergency power starting equipment and easy to produce large impact on equipment is solved.

[0035] The output control strategy of the emergency starting power supply is applied to the power supply, so that the difficult to control large current discharge output can be effectively controlled, and the safety is greatly improved. The output of the emergency power supply is controllable, which ensures the power quality of the emergency power supply output, improves the safety performance of the product, and provides continuous, effective and reliable power supply for the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The control system block diagram of the present application;

[0037] Figure 2 The control flowchart of the present application;

[0038] Figure 3 The charging and discharging strategy schematic diagram of the prior art; DETAILED DESCRIPTION

[0039] The control system of super capacitor large current discharge comprises: a battery module, a super capacitor module, a power consuming device and a standby switching feedback source. The battery module provides electric energy for the super capacitor module. The super capacitor module stores electric energy and provides large current discharge for the power consuming device. An input current sensor is installed on the circuit connecting the battery module and the super capacitor module. A feedback current sensor is installed on the circuit connecting the battery module and the power consuming device. The standby switching feedback source comprises a CPU and a variable resistor. The input current sensor and the feedback current sensor are connected with the input end of the CPU respectively. The variable resistor is connected with the control end of the CPU. The CPU receives the input current signal and the feedback current signal sent by the input current sensor and the feedback current sensor and compares them. When the ratio between the feedback current and the input current exceeds the set range, the CPU controls the variable resistor to change the internal resistance value, so that the super capacitor discharge process constitutes a closed loop. The super capacitor large current discharge is continuously fed back and corrected.

[0040] The control method of super capacitor large current discharge comprises the following processes:

[0041] The input current sensor transmits the input current of the super capacitor to the CPU of the standby switching feedback source. The feedback current sensor transmits the feedback current of the super capacitor to the CPU of the standby switching feedback source.

[0042] The CPU of the standby switching feedback source receives the input current and the feedback current and compares them. When the ratio between the feedback current and the input current exceeds the set range, the CPU controls the variable resistor to change the internal resistance value, so that the super capacitor large current discharge is continuously fed back and corrected.

[0043] Further, the method that the CPU controls the variable resistor to change the internal resistance value and continuously feeds back and corrects the super capacitor large current discharge is as follows:

[0044] The battery provides output electric energy to the power consuming device through the front channel. The output electric energy is fed back to the standby switching source control to form a feedback channel. It can be concluded that:

[0045] E (s) = R (s) -B (s)

[0046] E (s) : deviation control signal

[0047] R (s) : battery discharge output

[0048] B (s) : sampling feedback signal

[0049] That is, the supplement of the battery pack to the super capacitor by the control loop is inputted by the standby switching source and the battery, and during the discharging process of the battery pack, the open loop transfer function of the switching control system can be obtained by Laplace transformation of the sampling feedback signal and the deviation control signal

[0050] The pre-phase channel transfer function of the switching control system can be obtained by Laplace transformation of the output signal and the deviation signal Therefore, for the negative feedback connection of the system, the negative feedback control is according to C (s) =[R (s) -H (s) C (s) ]G (s) .

[0051] The output power (including voltage and current) of the line is tracked and monitored by the sampling resistor, the data is linearly processed, and the control is performed according to C (s) =[R (s) -H (s) C (s) ]G (s) , and the output current is controlled by the change of the line impedance value through the silicon controlled rectifier, and the large current output is outputted by the solid state relay, so that the super capacitor group can complete the instantaneous large power discharge, the high power instantaneous output, and the peak current during the output can reach thousands of amperes to start the engine and other equipment. The instantaneous large power discharge technology has strong large current discharge capacity, high energy conversion efficiency, small process loss, large current energy circulation efficiency ≥ 90%, simple discharge line, high safety factor, long-term use without maintenance, and good ultralow temperature characteristics.

[0052] Meanwhile, the resistance is added to hinder the rapid discharge, the self-switching module is designed to limit the current, the super capacitor is switched, the purpose of increasing the internal resistance and the capacity of the super capacitor group is achieved, and the specific control process is as shown in Figure 2 .

[0053] In summary, the super capacitor large current discharge control system protected by the application can effectively control the difficult-to-control large current discharge output and greatly improve the safety.

[0054] The above only describes the preferred embodiments of the application and is not used to limit the application. For those skilled in the art, the application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application shall be included in the protection scope of the application.

Claims

1. A control system for supercapacitor high current discharge, characterized by, The application relates to a battery module, a super capacitor module, an electric device and a standby switching feedback source, wherein the battery module provides electric energy for the super capacitor module, the super capacitor module stores electric energy and provides large-current discharge for the electric device, an input current sensor is installed on a circuit connected between the battery module and the super capacitor module, a feedback current sensor is installed on a circuit connected between the battery module and the electric device, the standby switching feedback source comprises a CPU and a variable resistor, the input current sensor and the feedback current sensor are connected with input ends of the CPU respectively, the variable resistor is connected with a control end of the CPU, the CPU receives input current signals and feedback current signals sent by the input current sensor and the feedback current sensor, and compares the input current signals and the feedback current signals, when a ratio between the feedback current and the input current exceeds a set range, the CPU controls the variable resistor to change an internal resistance value, so that a super capacitor module discharge process constitutes a system closed loop, and the super capacitor module large-current discharge is continuously fed back and corrected; The CPU controls the variable resistor to change the internal resistance value, and the super capacitor module large-current discharge is continuously fed back and corrected in the following mode: The battery module supplies output electric energy to the super capacitor module to form a front-phase channel for the electric device, the output electric energy is fed back to the standby switching feedback source control to form a feedback channel, and the following formula is obtained: E(s)=R(s)-B(s); E(s): deviation control signal; R(s): battery module discharge output; B(s): sampling feedback signal; The application further relates to a flow process, which comprises the following steps: The supplementary charging of the super capacitor module by the battery module is controlled by the standby switching feedback source input and the battery module input control. During the discharging process of the battery module, the open loop transfer function of the switching control system is obtained by Laplace transformation of the sampling feedback signal and the deviation control signal ratio, which is , The Laplace transform of the battery module output signal and the deviation control signal is compared to obtain the front channel transfer function of the switching control system as For the negative feedback connection of the system, the negative feedback control is controlled according to ; wherein: H(s) represents the transfer function of the feedback channel.

2. A method of controlling the discharge of a supercapacitor at high current, characterized in that, The input current sensor transmits input current of the super capacitor module to the CPU of the standby switching feedback source, and the feedback current sensor transmits feedback current of the super capacitor module to the CPU of the standby switching feedback source; The CPU of the standby switching feedback source receives the input current and the feedback current, and compares the input current and the feedback current, when a ratio between the feedback current and the input current exceeds a set range, the CPU controls the variable resistor to change the internal resistance value, so that the super capacitor large-current discharge is continuously fed back and corrected; The CPU controls the variable resistor to change the internal resistance value, and the super capacitor large-current discharge is continuously fed back and corrected in the following mode: The battery module supplies output electric energy to the super capacitor module to form a front-phase channel for the electric device, the output electric energy is fed back to the standby switching feedback source control to form a feedback channel, and the following formula is obtained: E(s)=R(s)-B(s) E(s): deviation control signal R(s): battery module discharge output B(s): sampling feedback signal ​ The supplementary charging of the super capacitor module by the battery module is controlled by the standby switching feedback source input and the battery module input control. During the discharging process of the battery module, the open loop transfer function of the switching control system is obtained by Laplace transformation of the ratio of the sampling feedback signal and the deviation control signal . The pre-phase channel transfer function of the switching control system is obtained by Laplace transformation of the ratio of the battery module output signal and the deviation control signal . The negative feedback control is controlled according to for the negative feedback connection of the system.

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