CN203589825U - Supercapacitor based inductive energy taking power supply device of high voltage measuring system - Google Patents

Abstract

The utility model relates to an inductive energy harvesting power supply device for a high voltage measurement system based on a supercapacitor, comprising a current transformer, a rectification filter circuit, a DC/DC module, a lithium battery and a power management unit. filter circuit, and then through the DC/DC module to output a stable voltage, it also includes a super capacitor, the power management unit includes a super capacitor charging control circuit and a lithium battery charging control circuit, and the DC/DC module supplies the super capacitor charging control circuit through the super capacitor charging control circuit. Capacitor charging, the supercapacitor supplies power to the load, and the DC/DC module charges the lithium battery through the lithium battery charging control circuit, and the lithium battery supplies power to the load. The supercapacitor is used as the energy storage device to solve the problems of the power supply device used in the existing ring network cabinet on-line monitoring system, such as less cycle times, large maintenance, large volume, and the need for power failure to transform the existing ring network cabinet.

Description

Inductive energy harvesting power supply device for high voltage measurement system based on supercapacitor

technical field

The utility model relates to a power supply technology, in particular to a power supply device based on high-voltage measurement system induction energy harvesting.

Background technique

The power supply problem of high-voltage measurement system is a difficult point in engineering application at present, and the research on stable, reliable and low-power power supply has important engineering use value.

At present, the commonly used power supply methods include solar energy, storage battery, laser function, bus induction energy acquisition, etc. Due to the large size of solar panels, it is not conducive to installation and is easily affected by the climate. It is not suitable for online equipment in the rainy and foggy climate conditions in the south; the voltage transformer has high insulation requirements and is susceptible to temperature, stray capacitance and Electromagnetic interference and other factors. Although the power output can be adjusted by changing the size of the capacitor C, the selection of a large capacitor may generate harmonics, resulting in unstable voltage division and affecting subsequent circuits; The efficiency and efficiency are very low; the most promising power supply method is to extract electric energy from the transmission line, set the energy-taking coil on the wire to induce the AC voltage, and then output a stable and reliable DC after rectification, filtering, and voltage stabilization to realize the isolated powered by.

At present, many online monitoring systems of high-voltage transmission lines in power systems adopt GSM/GPRS data transmission mode. The GSM/GPRS module has high power at the moment of data transmission and reception, and the current will be as high as several hundred milliamperes, while the working current in standby mode is only 10-20 mA. Using inductive energy harvesting, the output power of the power supply is very small under the condition of low current, which is not enough to provide enough high-power electric energy for data transmission and reception. The energy harvesting coil cooperates with the floating charging method of lithium-ion batteries, which has disadvantages such as complex charging management of lithium-ion batteries and limited charging temperature. The supercapacitor is added to the design of the power supply circuit, which solves the difficulty of instantaneous high-power power supply, and the circuit is simple and easy to maintain.

Contents of the invention

The technical problem to be solved by the utility model is to provide a supercapacitor-based high-voltage measurement system induction energy harvesting power supply device for the above-mentioned deficiencies in the background technology, using a supercapacitor as an energy storage device, a special current transformer (TA) and a lithium battery Lithium batteries can ensure the characteristics of instruments and equipment, and do a good job in the maintenance of instruments and equipment. The experiment completes the two-way energy harvesting, which solves the problems of the power supply device used in the existing ring main unit online monitoring system, such as the low number of cycles, large maintenance, large volume, and the need for power outages to transform the existing ring main unit.

Technical solutions

In order to achieve the above object, the technical scheme proposed by the utility model is as follows:

The high-voltage measurement system based on supercapacitors senses energy harvesting power supply devices, including current transformers, rectification and filtering circuits, DC/DC modules, lithium batteries, and power management units. The alternating current is converted into direct current, and then a stable voltage is output through the DC/DC module, which also includes a supercapacitor. The power management unit includes a supercapacitor charging control circuit and a lithium battery charging control circuit. The supercapacitor is charged, and the supercapacitor supplies power to the load. At the same time, the DC/DC module charges the lithium battery through the lithium battery charging control circuit, and the lithium battery supplies power to the load.

As a further optimization solution of the present invention, the current transformer includes an iron core and a coil wound on the iron core, and the coil is a coil with air gaps at one or both ends.

As a further optimization scheme of the utility model, it also includes an impact protection circuit, the output end of the coil is connected to the impact protection circuit, and the impact protection circuit is connected to the input end of the rectification filter circuit.

As a further optimization scheme of the utility model, it also includes an overvoltage protection circuit, the input end of the overvoltage protection circuit is connected to the output end of the rectification filter circuit, and one output end of the overvoltage protection circuit is connected to the charging end of the lithium battery. One output end is connected to the input end of the DC/DC module.

As a further optimization solution of the present invention, the supercapacitor includes first and second supercapacitors, the DC/DC module charges the first supercapacitor, the first supercapacitor charges the second supercapacitor, and the second supercapacitor charges the second supercapacitor. Two supercapacitors supply power to the load.

Beneficial effect

(1) Compared with the storage battery, this method can take power online and charge the supercapacitor without replacing the battery;

(2) Compared with solar cells, this method has high energy density and high energy conversion rate, and can provide reliable power supply in various climates;

(3) Compared with the combination method of busbar energy harvesting and storage battery, the supercapacitor in this method can partially replace the function of the battery, and is superior to the battery in terms of charge and discharge times and service life. In addition, when the monitoring system has a data remote transmission device, the instantaneous high-power discharge characteristics of the supercapacitor can well meet the high-power demand at the moment of sending data without causing a large voltage drop.

Description of drawings

Fig. 1 is a functional block diagram of an energy harvesting power supply;

Figure 2(a) is a structural diagram of a conventional coil;

Figure 2(b) is a structural diagram of the improved coil;

Figure 3 Comparison of magnetization curves before and after iron core improvement;

Fig. 4 is a circuit schematic diagram of an overvoltage protection circuit;

Fig. 5 is a supercapacitor charging control circuit diagram;

Fig. 6 is a schematic diagram of the circuit of the power management unit.

Detailed ways

As shown in Figure 1, the utility model discloses an inductive energy harvesting power supply device for a high-voltage measurement system based on a supercapacitor, including a current transformer, an impact protection circuit, a rectification filter circuit, an overvoltage protection circuit, a DC/DC module, two Supercapacitors, lithium batteries, and power management units. The special TA is set on the high-voltage cable, and uses the principle of electromagnetic induction to sense energy from the high-voltage cable through the current transformer, and converts the alternating current into direct current through the rectification and filtering circuit, and supplies the excess energy to the lithium battery through the overvoltage protection circuit on the one hand, and on the other hand Through the high-efficiency DC/DC module, the stable voltage is output to supply energy for the high-voltage measurement system. The power management unit includes a supercapacitor charging control circuit and a lithium battery charging control circuit. When the voltage is too large, the overvoltage protection circuit is started, and a part of the energy is supplied to the load through the DC/DC module (the DC/DC module is charged through the supercapacitor The control circuit charges the supercapacitor, and the supercapacitor supplies power to the load), and at the same time, the excess energy is charged to the lithium battery through the lithium battery charging control circuit, and the lithium battery supplies power to the load. This circuit effectively solves the problems of power endurance and output voltage stability through the supercapacitor charging control unit and the lithium battery charging control unit.

(1) Current transformer

As shown in Fig. 2(a), it is a current transformer in the prior art. The current transformer 1 includes an iron core and a coil wound on the iron core in turns.

When the iron core is magnetically saturated, the voltage on the secondary side is very unstable, and the induced voltage waveform is distorted when it is deeply saturated, becoming a peak pulse wave. Since the withstand voltage of the back-end electronic components is not high, the peak value increases to several hundred volts, which may cause serious consequences such as chip burnout. Long-term work in a deep saturation state will keep the iron loss high, and the coil temperature rise will be too high, which may cause high-frequency vibration or even burn out the coil. Therefore, try to prevent the iron core from working in a saturated state, and avoid working in a deep saturated state for a long time.

As shown in Figure 2(b) is the current transformer of the present invention, the coil is a single-ended or double-ended air-gapped coil, by introducing the air gap δ1 and δ2, the reluctance of the magnetic circuit is increased, and the magnetic resistance is reduced. The small relative permeability μr delays the H value when the iron core reaches saturation.

As shown in Figure 3, the comparison chart of the magnetization curve after the improvement of the iron core. Therefore, the silicon steel sheet with low magnetic permeability and high saturation magnetic induction is selected as the magnetic core material, and the structure is a split type.

(2) Shock protection circuit

In order to prevent the power supply circuit from being burned by lightning surge current and high instantaneous fault current, a transient suppression diode (TVS) (i.e. shock protection circuit) is used in front of the rectifier bridge, and the TVS limits the shock voltage output by the induction coil. That is, the output end of the current transformer is connected to the input end of the impact protection circuit, and the output end of the impact protection circuit is connected to the input end of the rectification and filtering circuit.

(3) Rectification filter circuit

Bridge rectification is used for rectification, and common π-type LC filter is used for filtering.

(4) Overvoltage protection circuit

The input terminal of the overvoltage protection circuit is connected to the output terminal of the rectification filter circuit, one output terminal of the overvoltage protection circuit is connected to the charging terminal of the lithium battery, and the other output terminal is connected to the input terminal of the DC/DC module. As shown in Figure 4, the left side is connected to the output terminal of the rectification filter circuit, the right side is connected to the input side of the DC/DC module, and the other side is connected to the input side of the charging chip. When the voltage across R3 is less than the operating voltage of the relay, the relay selects the "1" terminal, and all the filtered voltage is applied to both ends of the DC/DC module, and all the power is supplied to the load; when the voltage of R3 is greater than the operating voltage of the relay, the relay When the "2" terminal is selected, R1 is cut off, and the voltages of R2 and R3 are connected to the input terminal of the DC/DC module to supply the load; the voltage of R1 is connected to the input terminal of the lithium battery charging chip to provide energy for battery charging.

(5) Regulator circuit

A high-efficiency, high conversion rate, step-down voltage regulator module is selected, which has a high conversion rate and a wide input range. The high conversion rate is conducive to further reducing the starting current, and the wide input range enables the power supply to work in a larger primary current range.

(6) Supercapacitor charging control circuit

As shown in Figure 5, since the high-voltage power supply is different from other forms of power supply, its output power is greatly affected by the size of the load. When the bus current is constant, the output power will be insufficient as long as the load exceeds a certain range, because the voltage regulator chip There is a certain lower limit of voltage input. When the voltage is lower than the lower limit, the chip cannot start normally, and there is no output or the output is unstable. In order to minimize the bus current dead zone, in the case of using dual capacitors, charge C1 as a buffer, then supply C2 intermittently, and then output to the equivalent load RL, then the load voltage can fluctuate within a reasonable range, Thereby reducing the current dead zone, and the electrical appliances can work normally when the output power is slightly insufficient. When the voltage across RL is higher than the lower limit of the action voltage of D1, D1 outputs high level, VT1 is disconnected, and the DC/DC module charges C1; when the voltage across RL is lower than the lower limit of D1 voltage, D1 outputs low level, VT1 When it is turned on, DC/DC charges C1 while C1 charges C2.

(7) Power management unit

   As shown in Figure 6, the output terminal of the DC/DC module charges the first supercapacitor, the output terminal of the second comparator D2 is connected to the control terminal of the fourth switch circuit, and the fourth switch circuit is connected in series with the DC/DC module output protection The resistance Rp, the fourth switch circuit in series and the two ends of the protection resistor Rp are connected in parallel to the two output terminals of the DC/DC module, the positive output terminal of the DC/DC module is connected to the input terminal of the first switch circuit, and the first switch circuit The control terminal of the first comparator is connected to the output terminal of the first comparator D1, the negative input terminal of the first comparator D1 is connected to the positive pole of the load, the output terminal of the first switch circuit is connected to the input terminal of the second switch circuit, and the output terminal of the second switch circuit The terminal is connected to the output terminal of the third switch circuit, the lithium battery discharge output terminal is connected to the input terminal of the third switch circuit, and the output terminal of the second switch circuit is connected to the positive pole of the load through a diode. The bases of the second switch circuit and the third switch circuit are connected to each other, the enabling terminal of the lithium battery charging control circuit is connected to the output terminal of the third comparator D3, and the negative input terminal of the third comparator D3 is connected to the positive pole of the load. The supercapacitor includes first and second supercapacitors, the DC/DC module charges the first supercapacitor, the first supercapacitor charges the second supercapacitor, and the second supercapacitor supplies power to the load.

In the power management unit, the left side is connected to the output of the overvoltage protection circuit. The first and second comparators are single-supply hysteresis comparators, in which the first comparator D1, the second comparator D2 and the third comparator D3 are used in reverse phase, and the third comparator D3 is a general comparator; the first switch The circuit VT1, the second switch circuit VT2, the third switch circuit VT3 and the fourth switch circuit VT4 are respectively MOSFET tubes used as selector switches; the diode VD1 is used to prevent the current in the second supercapacitor C2 from flowing back into the first supercapacitor C1 and lithium battery (the first one passes through C2→VD1→VT3→voltage regulator chip→charging control chip. The second one passes through VD1→VT2→VT1→C1), causing the circuit to fail to work normally; because the voltage of each lithium battery is at 4.2 V is about V, so this design uses 2 lithium batteries for power supply, and a voltage regulator is used at the back end to obtain + 5V output; the output protection resistor Rp of the DC/DC module is the output protection resistor of the DC/DC module. The charge and discharge control function of the lithium battery is realized by the third comparator D3. In this design, as shown in Figure 1, the DC/DC output module also charges the lithium battery while supplying power to the load. When the terminal voltage of the load RL is higher than 4.8V, the enable terminal S/S input high level of LT1512 starts to work normally, charging the lithium battery and the first supercapacitor C1; when the terminal voltage of the load RL is lower than 4.8V When V, the S/S terminal inputs a low level, and the charging of the battery stops. At this time, while the DC/DC output module is charging the first supercapacitor C1, the first supercapacitor C1 is also charging the second supercapacitor C2, and then the second The supercapacitor C2 supplies power to the load. The power supply selection and DC/DC module output protection functions are realized by the second switch circuit VT2, the third switch circuit VT3, the fourth switch circuit VT4 and the second comparator D2. The second switch circuit VT2 and the third switch circuit VT3 are connected back to back to realize the selection of the DC/DC module output or the lithium battery to supply power to the load. When ensuring the normal operation of the load RL, the lower limit of the action of the second comparator D2 is lower than 4.8V, and at the same time, the action of the third comparator D3 is earlier than that of the second comparator D2, so that when the power of the DC/DC module is insufficient Suspend the charging of the lithium battery. If the load voltage continues to drop to the lower limit of the action of the second comparator D2, it means that the output power of the DC/DC module is still insufficient when only the load RL is on, and it can be determined that the DC/DC module cannot maintain the normal operation of the load RL. The second comparator D2 operates to output low level, (the charge control chip will supply power to the load RL through the voltage regulator chip), the third switch circuit VT3 is turned on, the second switch circuit VT2 is turned off, and the load RL is powered by the lithium battery. When the output power of the DC/DC module is sufficient, the second comparator D2 outputs a high level, the second switch circuit VT2 is turned on, and the third switch circuit VT3 is turned off. At this time, the DC/DC module supplies power to the load RL. The action of the fourth switching circuit VT4 is controlled by the second comparator D2. Since the secondary side cannot be opened, otherwise a large voltage will appear and cause damage to the DC/DC module itself and the circuit, so a protection resistor Rp is added in the design. When the load RL is powered by a lithium battery, the second comparator D2 outputs a low level, the fourth switch circuit VT4 is turned on, and the protection resistor Rp is connected in parallel to both ends of the first supercapacitor C1 as an equivalent load of the load RL. The resistance value can be configured according to the actual normal load size.

Claims (5)

1. the Transmission System for High Voltage Measurements induction energy fetching supply unit based on super capacitor, comprise current transformer, current rectifying and wave filtering circuit, DC/DC module, lithium battery and Power Management Unit, by current transformer from high-tension cable induction energy fetching, through current rectifying and wave filtering circuit, alternating current is transformed to direct current, pass through again the voltage of DC/DC module stable output, it is characterized in that: also comprise super capacitor, described Power Management Unit comprises super capacitor charging control circuit and lithium cell charging control circuit, DC/DC module is charged to super capacitor by super capacitor charging control circuit, super capacitor is load supplying, DC/DC module is passed through lithium cell charging control circuit to lithium cell charging simultaneously, lithium battery is load supplying.

2. the Transmission System for High Voltage Measurements induction energy fetching supply unit based on super capacitor according to claim 1, is characterized in that: described current transformer comprises iron core and around the coil on iron core, and described coil is single-ended or both-end is opened the coil of air gap.

3. the Transmission System for High Voltage Measurements induction energy fetching supply unit based on super capacitor according to claim 2; it is characterized in that: also comprise impact protection circuit; described coil output is connected to impact protection circuit, and described impact protection circuit is connected to the input of current rectifying and wave filtering circuit.

4. the Transmission System for High Voltage Measurements induction energy fetching supply unit based on super capacitor according to claim 1 and 2; it is characterized in that: also comprise overvoltage crowbar; the input of overvoltage crowbar is connected to the output of current rectifying and wave filtering circuit; overvoltage crowbar Yi road output is connected to the charging end of lithium battery, and another road output is connected to DC/DC module input.

5. the Transmission System for High Voltage Measurements induction energy fetching supply unit based on super capacitor according to claim 1 and 2, it is characterized in that: described super capacitor comprises first, second ultracapacitor, described DC/DC module is described the first ultracapacitor charging, the first ultracapacitor is the second ultracapacitor charging, and the second ultracapacitor is load supplying.

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