Fast and efficient charging circuit for super capacitor and implementation method

Abstract

The invention discloses a fast and efficient charging circuit for a super capacitor and an implementation method, and belongs to the technical field of rail transit communication. The charging power supply is respectively connected with the control unit and the super capacitor, and the super capacitor is connected with the control unit; the charging power supply is used for charging the super capacitor; the control unit is used for controlling output voltage of the charging power supply; the super capacitor is an energy storage device and is charged after the connected equipment is powered on to store electric energy for continuously supplying power to the equipment after the equipment is powered off. The control circuit composed of a single-chip microcomputer is adopted to control the dynamic output of the charging power supply, so that the charging current is about 1A, the efficiency of the charging power supply under the load current is more than 90%, for a 10-farad capacitor in the charging circuit, the time for charging the 10-farad capacitor to the rated voltage of 12V is less than 2 minutes, rapid and efficient charging of the super capacitor is realized, and the charging efficiency of the super capacitor is improved. And the charging circuit does not have a device which generates heat seriously.

Description

Technical Field

[0001] The present invention relates to the field of rail transit communication technology, and in particular to a supercapacitor fast and efficient charging circuit and an implementation method for use in a rail vehicle-to-ground communication system. Background Art

[0002] Traditional subway communication devices and network equipment generally have operating systems, which require power to be provided to the equipment within a short period of time (usually a few seconds to more than ten seconds) when shutting down or accidentally losing power, in order to ensure that the equipment saves data and safely shuts down the system. This is where supercapacitors are used. The so-called supercapacitors refer to capacitors with large capacitance, usually above the farad level. After the equipment is powered on, the supercapacitor must be fully charged in preparation for use after the equipment is powered off. Most of them now use constant voltage and current limiting circuits to charge supercapacitors. The charging circuit has two obvious defects: 1. The current limiting device generates severe heat, resulting in low charging efficiency. 2. The charging time is long. Since the charging power supply outputs a constant voltage and is current limited, the charging speed in the second half is slow, and supercapacitors cannot be used normally in an environment with frequent power outages. Summary of the invention

[0003] In view of the shortcomings of the prior art, such as slow charging speed, low efficiency and serious heating devices in the charging circuit, the present invention provides a supercapacitor fast and efficient charging circuit and an implementation method, starting from improving the efficiency of the charging circuit and shortening the charging time, the output voltage of the charging power supply is dynamically adjusted to follow the voltage on the supercapacitor and output a suitable charging current. If the charging current is too large, the burden on the power supply of the main device will be increased, bringing risks to the startup of the main device system. If the charging current is too small, the charging time will be increased.

[0004] The present invention adopts a method for controlling the output voltage of the charging power supply. The voltage follows the voltage on the supercapacitor and is higher than the voltage of the supercapacitor by a certain value, which is 0.1V. This makes the charging current within a suitable range, ensuring both the charging speed and high charging efficiency without consuming too much power, which would bring a heavy burden to the power supply of the equipment.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is as follows: a supercapacitor fast and efficient charging circuit, comprising a charging power supply, a control unit, and a supercapacitor; the charging power supply is respectively connected to the control unit and the supercapacitor, and the supercapacitor is connected to the control unit; the charging power supply is used to charge the supercapacitor; the control unit is used to control the output voltage of the charging power supply; the supercapacitor is an energy storage device, which charges and stores electric energy after the connected device is powered on, and is reserved for continuing to power the device after the device is powered off.

[0006] A method for realizing a supercapacitor fast and efficient charging circuit, wherein the charging circuit is applied to a communication device using a supercapacitor; when the device is powered on, the single-chip microcomputer N1 of the control unit is initialized, the 6th pin of the single-chip microcomputer N1 outputs a low level, which is added to the 7th pin of the charging power synchronous buck chip N2, the synchronous buck chip N2 is turned off, the voltage of the supercapacitor is divided by resistors R4 and R5, and sent to the 13th pin of the single-chip microcomputer N1, and after A / D conversion, it is U, where U is a real number in volts, and the voltage of the supercapacitor detected by the single-chip microcomputer N1 is U C =U*(1+R4 / R5), the internal program of the microcontroller N1 determines whether this voltage is less than the available value of the supercapacitor. If it is less than the available value, the level U of the control charging power supply is reduced. P , charging power supply output voltage U O with U P Determined by the following formula: U O =-8 U P +25.025 (1) U O : Charging power supply output voltage, unit: V, U P :The microcontroller controls the level of the charging power supply, unit: V, Transformed into the following formula U P =-0.125 U O +3.128 (2) Pin 6 of the single-chip microcomputer N1 outputs a high level, turning on the synchronous buck chip N2. To make the output voltage of the charging power supply U C +0.1V, the microcontroller calculates the output voltage of pin 25 according to formula (2): U P =-0.125 (U C +0.1)+3.128 Will U C =U*(1+R4 / R5) into the equation, we get U P =-0.125 (U*(1+R4 / R5)+0.1)+3.128 Charge the supercapacitor; after a delay of 0.1 seconds, detect the voltage of the supercapacitor again to determine whether the voltage on the supercapacitor is lower than the rated value. If it is lower than the rated value, return to the set output voltage of the charging power supply and turn on the charging power supply. If it is not lower than the rated value, return to turn off the charging power supply, thereby achieving the purpose of quickly charging the supercapacitor.

[0007] The beneficial effects of the present invention are as follows: First, a charging power supply with an adjustable output voltage is used, and the core of the charging power supply is a synchronous buck chip. This buck chip has a high efficiency under a suitable load current, so that the output voltage of the charging power supply tracks the voltage of the supercapacitor, which can ensure that the charging power supply has a suitable output current to charge the supercapacitor and achieve the highest charging efficiency. At the same time, the current limiting resistor in the charging circuit is saved, the heating device and useless power consumption are reduced, and the charging power supply continuously and efficiently charges the supercapacitor, which naturally shortens the charging time and achieves the purpose of efficient and fast charging. Second, a control unit with a single-chip microcomputer as the core is used to detect the voltage on the supercapacitor, and the output voltage of the charging power supply is controlled according to this voltage. Third, the charging power supply is turned off after the supercapacitor is charged to the specified voltage, and the charging program is started again until the voltage of the supercapacitor drops below the available voltage.

[0008] In summary, this application uses a control circuit composed of a single-chip microcomputer to control the dynamic output of the charging power supply so that the charging current is about 1A. The efficiency of the charging power supply under this load current is above 90%. For the 10 Farad capacitor in this charging circuit, it takes less than 2 minutes to charge to the rated voltage of 12V, thereby achieving fast and efficient charging of the supercapacitor, and there are no devices with severe heat generation in the charging circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural block diagram of the charging circuit of the present invention; Figure 2 is a circuit diagram of a charging circuit of the present invention; Figure 3 is a schematic diagram of a circuit for implementing the present invention; Figure 4 The present invention is a flowchart of the method for implementing the present invention. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solution and advantages of the implementation methods of this application clearer, the technical solution of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described implementation methods are part of the implementation methods of this application, not all of the implementation methods. Based on the implementation methods in this application, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0011] like Figure 1 As shown, a supercapacitor fast and efficient charging circuit includes a charging power supply, a control unit, and a supercapacitor; the charging power supply is a switching power supply with an adjustable output voltage, the control unit is a detection and control circuit with a single chip microcomputer as the core, and the supercapacitor can be a single supercapacitor or a supercapacitor group.

[0012] The control unit makes the charging power supply track the voltage of the supercapacitor at all times, so that the output voltage of the charging power supply is slightly higher than the voltage of the supercapacitor. There is no need to set a current limiting resistor in the charging circuit, which reduces power loss. The charging current is about 1A. Under this output current state, the efficiency of the charging power supply is above 90%. Since the charging power supply continues to charge the supercapacitor with a current of about 1A, the purpose of efficient and fast charging is achieved. The supercapacitor is an energy storage device. After the connected device is powered on, it charges and stores electrical energy to continue to power the device after the device is powered off, ensuring device data storage and system safe shutdown. The charging power supply uses the controlled FR9888 synchronous buck chip N2, with a maximum efficiency of 96%. The control unit uses the STM32F030K6T6 microcontroller N1, which has 2 ADC and PWM outputs, can detect the voltage of the supercapacitor, output control analog voltage signals, and control the output voltage of the charging power supply.

[0013] like Figure 2 As shown, the specific circuit of the charging circuit is that pin 1 of the synchronous buck chip N2 is connected to pin 3 of the synchronous buck chip N2 and one end of the inductor L1 through the capacitor C3, the other end of the inductor L1 is connected to capacitor C4, capacitor C5, resistor R1 and one end of the resistor R4 and the positive electrode of the super capacitor, the other end of the resistor R4 is connected to one end of the resistor R5 and pin 13 of the single-chip computer N1, the other ends of the capacitors C4, C5 and resistor R5 and the negative electrode of the super capacitor are grounded respectively, pin 2 of the synchronous buck chip N2 is connected to one end of the capacitor C6, capacitor C7 and the input voltage VCC respectively, pin 5 of the synchronous buck chip N2 is connected to resistor R2, capacitor C11, one end of the resistor R3 and the other end of the resistor R1 respectively, the other end of the resistor R3 is connected to the microcontroller N1 through the diode VD1 Pin 25 and one end of resistor R6 and capacitor C12, pin 7 of synchronous buck chip N2 is connected to pin 6 of single-chip microcomputer N1, pin 8 of synchronous buck chip N2 is connected to one end of capacitor C10, capacitor C6, capacitor C7, capacitor C10, capacitor C11, capacitor C12, resistor R2, resistor R6, and pin 4 of synchronous buck chip N2 are grounded respectively, pin 1, pin 17, and pin 5 of single-chip microcomputer N1 are connected to one end of capacitor C1 and capacitor C2 and a 3.3V power supply respectively, pin 2 of single-chip microcomputer N1 is connected to crystal oscillator G1 and one end of capacitor C9 respectively, pin 3 of single-chip microcomputer N1 is connected to the other end of crystal oscillator G1 and one end of capacitor C8 respectively, and the other ends of capacitor C1, capacitor C2, capacitor C8, capacitor C9 and pin 16 and pin 32 of single-chip microcomputer N1 are grounded respectively; The model of the microcontroller N1 is: STM32F030K6T6, the model of the synchronous buck chip N2 is: FR9888, The supercapacitor has a withstand voltage of 16V and a capacity of 10 Farads.

[0014] Figure 3This is the application diagram of the charging circuit in a subway communication radio. The host power supply converts the 110V powering the radio into 12V to power the mainboard and the charging power supply. The supercapacitor has a withstand voltage of 12V and a capacity of 10 farads. After the device is powered on, the control unit detects the voltage on the supercapacitor, outputs the control level, and adds it to the feedback input pin of the charging power supply, thereby controlling the output of the charging power supply so that the output voltage of the charging power supply matches the voltage of the supercapacitor, and quickly charges the supercapacitor. The supercapacitor can be charged to the rated voltage of 11.4V within 2 minutes. When the radio is turned off, the 110V power supply is disconnected, the switching circuit detects that the main power supply is off, and switches to the supercapacitor to power the mainboard. The mainboard of the radio starts a series of operations for safe shutdown: storing data, storing logs, and exiting the system. After completing these operations, the radio is safely shut down.

[0015] Before using this charging circuit, the radio circuit did not have a control unit connected to the charging power supply. The charging power supply had a constant voltage output and a current-limiting resistor was installed in the charging circuit. It took at least 10 minutes to charge to the rated voltage, and the charging power supply would generate a certain amount of heat during the charging process.

[0016] By adopting the circuit of the present invention, a control unit of a charging power supply is added, and the charging power supply is changed into a step-down switching power supply with controlled output voltage, so that its output voltage follows the voltage of the supercapacitor, and the supercapacitor is charged efficiently, which not only greatly shortens the charging time, but also avoids the heating phenomenon of the charging power supply, thereby meeting the requirements of fast and efficient charging of the supercapacitor.

[0017] Embodiment 1, as Figure 4 As shown, a method for implementing a supercapacitor fast and efficient charging circuit, the charging circuit is applied in a communication device using a supercapacitor; When the device is powered on for the first time, the microcontroller N1 is initialized, and the 6th pin of the microcontroller N1 outputs a low level, which is added to the 7th pin of the synchronous buck chip N2, making the synchronous buck chip N2 in a dormant state. The voltage of the supercapacitor is divided by resistors R4 and R5 and sent to the 13th pin of the microcontroller N1. The internal program of the microcontroller N1 performs AD conversion on this voltage and obtains the value U, which is a real number in volts. It is the voltage value of the supercapacitor after the voltage is divided by R4 and R5. Then the voltage U of the supercapacitor is C =U*(1+R4 / R5), the program inside the microcontroller N1 determines whether this voltage is less than the available value of the supercapacitor (the minimum value of the supercapacitor voltage that can ensure device data storage and normal shutdown after power failure). If it is less than the available value, the DC level value U output by the microcontroller 25 pin is reduced. P , through diode VD1 and resistor R3, added to pin 5 of synchronous buck chip N2, the charging power supply output voltage U O The DC level value U output from the MCU 25 pin PDetermined by the following formula: U O =-8 U P +25.025 (1) U O : Charging power supply output voltage, unit: V, U P : The DC voltage output from pin 25 of microcontroller N1, unit: V Transformed into the following formula U P =-0.125 U O +3.128 (2) Pin 6 of the single-chip microcomputer N1 outputs a high level, turning on the synchronous buck chip N2. To make the output voltage of the charging power supply U C +0.1V, the microcontroller calculates the output voltage of pin 25 according to formula (2): U P =-0.125 (U C +0.1)+3.128 Will U C =U*(1+R4 / R5) into the equation, we get U P =-0.125 (U*(1+R4 / R5)+0.1)+3.128 Charge the supercapacitor; after a delay of 0.1 seconds, detect the voltage of the supercapacitor again and repeat the above charging steps until the supercapacitor voltage reaches the rated value (the highest charging voltage specified in the supercapacitor specification), the 6th pin of the microcontroller N1 outputs a low level, and the synchronous buck chip N2 is turned off; the charging of the supercapacitor is completed.

[0018] From the above charging process, we can see that the output of the charging power supply closely tracks the voltage of the supercapacitor under the control of the microcontroller, so that the output of the charging power supply and the load - the supercapacitor are matched throughout the charging process, thereby achieving the purpose of efficient and fast charging of the supercapacitor and reducing useless power consumption.

Claims

1. A supercapacitor fast and efficient charging circuit, characterized in that: It includes a charging power supply, a control unit, and a supercapacitor; the charging power supply is connected to the control unit and the supercapacitor respectively, and the supercapacitor is connected to the control unit; the charging power supply is used to charge the supercapacitor; the control unit is used to control the output voltage of the charging power supply; the supercapacitor is an energy storage device, which charges and stores electric energy after the connected device is powered on, and is reserved for continuing to power the device after the device is powered off.

2. A supercapacitor fast and efficient charging circuit according to claim 1, characterized in that: The specific circuit of the charging circuit is as follows: Pin 1 of the synchronous buck chip N2 is connected to Pin 3 of the synchronous buck chip N2 and one end of the inductor L1 through the capacitor C3; the other end of the inductor L1 is connected to the capacitor C4, the capacitor C5, the resistor R1, one end of the resistor R4 and the positive electrode of the super capacitor; the other end of the resistor R4 is connected to one end of the resistor R5 and Pin 13 of the single-chip computer N1; the other ends of the capacitor C4, the capacitor C5, the resistor R5 and the negative electrode of the super capacitor are grounded respectively. Pin 2 of the synchronous buck chip N2 is connected to one end of capacitor C6, capacitor C7 and input voltage VCC respectively. Pin 5 of the synchronous buck chip N2 is connected to resistor R2, capacitor C11, one end of resistor R3 and the other end of resistor R1 respectively. The other end of resistor R3 is connected to pin 25 of microcontroller N1 and one end of resistor R6 and capacitor C12 through diode VD1. Pin 7 of the synchronous buck chip N2 is connected to pin 6 of microcontroller N1. Pin 8 of the synchronous buck chip N2 is connected to one end of capacitor C10. Capacitors C6, C7 and C 10. Capacitor C11, capacitor C12, resistor R2, resistor R6, and pin 4 of synchronous buck chip N2 are grounded respectively. Pin 1, pin 17, and pin 5 of single-chip microcomputer N1 are connected to one end of capacitor C1 and capacitor C2 and a 3.3V power supply respectively. Pin 2 of single-chip microcomputer N1 is connected to crystal oscillator G1 and one end of capacitor C9 respectively. Pin 3 of single-chip microcomputer N1 is connected to the other end of crystal oscillator G1 and one end of capacitor C8 respectively. The other ends of capacitor C1, capacitor C2, capacitor C8, capacitor C9 and pin 16 and pin 32 of single-chip microcomputer N1 are grounded respectively. The model of the microcontroller N1 is: STM32F030K6T6, the model of the synchronous buck chip N2 is: FR9888, The supercapacitor has a withstand voltage of 16V and a capacity of 10 Farads.

3. A supercapacitor fast and efficient charging circuit according to claim 2, characterized in that: The supercapacitor is a single supercapacitor or a supercapacitor group.

4. A method for implementing the supercapacitor fast and efficient charging circuit according to claim 3, characterized in that: The charging circuit is used in communication equipment using supercapacitors. When the equipment is powered on, the microcontroller N1 of the control unit is initialized, and the 6th pin of the microcontroller N1 outputs a low level, which is added to the 7th pin of the charging power synchronous buck chip N2. The synchronous buck chip N2 is turned off, and the voltage of the supercapacitor is divided by resistors R4 and R5 and sent to the 13th pin of the microcontroller N1. After A / D conversion, it is U, which is a real number in volts. The voltage of the supercapacitor detected by the microcontroller N1 is U C =U*(1+R4 / R5), the internal program of the microcontroller N1 determines whether this voltage is less than the available value of the supercapacitor. If it is less than the available value, the level U of the control charging power supply is reduced. P , charging power supply output voltage U O with U P Determined by the following formula: IN O =-8 U P +25.025 (1) U O : Charging power supply output voltage, unit: V, U P :The microcontroller controls the level of the charging power supply, unit: V, Transformed into the following formula IN P =-0.125 U O +3.128 (2) Pin 6 of the single-chip microcomputer N1 outputs a high level, turning on the synchronous buck chip N2. To make the output voltage of the charging power supply U C +0.1V, the microcontroller calculates the output voltage of pin 25 according to formula (2): IN P =-0.125 (U C +0.1)+3.128 Will U C =U*(1+R4 / R5) into the equation, we get HE P =−0.125 (U*(1+R4 / R5)+0.1)+3.128 Charge the supercapacitor; after a delay of 0.1 seconds, detect the voltage of the supercapacitor again to determine whether the voltage on the supercapacitor is lower than the rated value. If it is lower than the rated value, return to the set output voltage of the charging power supply and turn on the charging power supply. If it is not lower than the rated value, return to turn off the charging power supply, thereby achieving the purpose of quickly charging the supercapacitor.

Images