CN116526698A - Self-tuning frequency stabilization system and method for wireless energy supply system of high-voltage iron tower monitoring equipment - Google Patents

Abstract

Self-tuning and frequency stabilization system and method for wireless energy supply system of high-voltage iron tower monitoring equipment. The energy harvesting device includes an energy harvesting coil, a transmission line passes through the energy harvesting coil, a magnetic coupling resonance wireless energy transmission device, and an energy transmitting device and an energy receiving device. Composed of two parts, the energy transmitting device is an energy conversion device including a high-frequency inverter circuit and a transmitting coil, which converts the direct current stored in the battery into a high-frequency alternating current through the high-frequency inverter circuit, and forms a mutual Coupled electromagnetic field; compared with the traditional new energy power supply system, the present invention can greatly reduce the consumption of fossil energy, improve the energy efficiency, and also reduce environmental pollution. The scope of work is also very wide. And it is not very sensitive to the change of the characteristic parameters of the controlled object, thus greatly improving the robustness of the control mode designed in the present invention.

Description

Self-tuning frequency stabilization system and method for wireless energy supply system of high-voltage iron tower monitoring equipment

technical field

The invention relates to the technical field of wireless power transmission for power generation, in particular to an autonomous tuning and frequency stabilization system and method for a wireless energy supply system for monitoring equipment of a high-voltage iron tower.

Background technique

In recent years, the intelligent visual online monitoring technology of transmission lines has become a hot topic of research at home and abroad. With the rapid development and application of intelligent visual online monitoring technology, how to provide power supply for monitoring equipment safely, stably and sustainably It has gradually become a "bottleneck" that restricts the in-depth development of intelligent vision online monitoring technology. In view of the fact that the current new energy power supply method cannot meet the requirements of continuity, high stability and high reliability of online monitoring equipment due to the influence of geographical environment and other factors, a new type of power supply is developed and applied to the online monitoring device of transmission lines. has great practical significance.

Based on the needs of the above-mentioned online monitoring equipment power supply technology, the online monitoring equipment wireless energy supply system was born for operation. This wireless power supply method can be applied to the field of power supply for online monitoring equipment of 110kV and below transmission lines, and is a new and reliable power supply device. The emergence of wireless power supply technology for high-voltage tower monitoring equipment has opened up a new idea for completely solving the power supply problem of online monitoring equipment. It also improves the power supply reliability of the current online monitoring device for high-voltage transmission lines, reducing the workload of maintenance work required by staff due to ash attached to photovoltaic panels and battery damage.

However, an important reason why the wireless power supply technology of high-voltage iron tower monitoring equipment has not been widely used is that the stability of the wireless energy transmission link of the wireless power supply technology cannot be guaranteed. Due to factors such as changes in the working environment temperature and transmission distance in the wireless energy transfer link, the resonant converter in the wireless energy transfer link may not be able to operate stably near the resonance state for a long time. This greatly reduces the practicality of the wireless power supply method.

In the current resonant frequency adjustment technology, manual adjustment and frequency modulation using phase-locked loop PLL are commonly used. Since manual frequency adjustment requires manual intervention, it is impossible to track the frequency in real time, resulting in low accuracy of this adjustment method. The second frequency modulation method is to use the phase-locked loop PLL to realize frequency adjustment. Compared with the manual frequency modulation method, the frequency modulation effect of this frequency modulation method is greatly improved, and the frequency modulation circuit structure based on the phase-locked loop PLL design is relatively simple. But because the intensity of its feedback signal is difficult to control, and often changes due to the change of the parameters of the resonant converter, this greatly limits the practical application of this control method.

Therefore, it is necessary to find a strategy that enables the wireless energy transfer system to independently tune and stabilize frequency, which has important practical significance for the efficient and stable operation of the wireless energy supply system for high-voltage tower monitoring equipment. It is also a technical problem to be solved urgently by those skilled in the art.

Contents of the invention

The technical problem to be solved by the present invention is to provide a self-tuning frequency stabilization system and method for the wireless energy supply system of the high-voltage iron tower monitoring equipment, so as to ensure the precise adjustment of the resonant frequency of the wireless energy transmission link in the wireless energy supply mode, and then solve the problem of the existing technology Technical problems of poor reliability and low efficiency.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

The self-tuning frequency stabilization system of the wireless energy supply system of the high-voltage iron tower monitoring equipment. The wireless energy supply system of the high-voltage iron tower monitoring equipment includes an energy harvesting device and a magnetically coupled resonant wireless energy transmission device. The energy harvesting device includes an energy harvesting coil. Energy coil, which converts the changing magnetic field energy near the transmission wire into corresponding low-frequency alternating current, and then converts it into direct current through a full-bridge rectifier circuit, and stores it in the battery for the subsequent stage circuit;

The magnetically coupled resonant wireless energy transmission device consists of two parts: an energy transmitting device and an energy receiving device. The energy transmitting device is an energy conversion device including a high-frequency inverter circuit and a transmitting coil, and converts the direct current stored in the battery through high-frequency inverter The circuit converts high-frequency alternating current and forms a mutually coupled electromagnetic field in the air through the receiving coil;

The energy receiving device uses magnetic resonance to generate high-frequency alternating current with the same frequency as that flowing through the transmitting coil inside the receiving coil, and then converts the high-frequency power into the direct current required by the online monitoring equipment through the rectification and voltage stabilization link, thereby supplying direct current load usage.

The circuit of the wireless energy supply system of the above-mentioned high-voltage iron tower monitoring equipment includes the main circuit of the wireless power supply system and the frequency control circuit;

_The main circuit of _the wireless power supply _system is composed of two parts: the induction energy harvesting circuit and the _wireless energy transmission circuit. Energy harvesting is carried out on L ₁ , _ip is the current flowing through the transmission wire, V _S is the output voltage of the power harvesting coil, and the output terminals of the full-bridge rectifier D ₁ ~ D ₄ are connected to the filter capacitor C _1n of the transmitter.

The above-mentioned wireless energy transmission circuit adopts a double-coil series topology main circuit structure, which is composed of a full-bridge inverter, a series resonant circuit at the transmitting end, a series resonant circuit at the receiving end, and a full-bridge rectifier circuit. The induction energy-taking circuit outputs a direct current i _dc Output to the full-bridge inverters S ₁ ~ S ₄ , the output terminals of the full-bridge inverters S ₁ ~ S ₄ are connected to the series resonant circuit of the transmitting end, the series resonant circuit of the transmitting end includes the inductance L _T of the transmitting coil in series, the parasitic The resistance r _T and the resonant compensation capacitor C _T at the transmitting end, the series resonant circuit at the receiving end includes a series receiving coil inductance _LD , the parasitic resistance r _D of the receiving circuit and the resonant compensation capacitor C _D at the receiving end, the receiving coil inductance _LD and the transmitting coil inductance Corresponding to L _T , _{i r} and i _D are the high-frequency resonant currents of _the transmitting _end and the receiving end respectively _. The end is connected to the receiving end filter capacitor C _2n .

The above-mentioned frequency control circuit includes a resonance voltage and current sampling circuit, a dynamic compensation tuning module circuit and a frequency tracking control module circuit;

The resonant voltage and current sampling circuit completes the detection of the voltage u(θ) _r and the resonant current i(θ) _r of the series resonant circuit at the transmitting end, and then passes u(θ) _r and i(θ) _r through the proportional amplifier and the difference At the same time, use the corresponding band-pass filter to filter out the redundant harmonic components, and then use the phase detection circuit and the current RMS detection circuit to obtain the pure resonance voltage and current fundamental wave components at this time. The effective value i _r of the current and the phase difference Δθ.

After the above-mentioned resonant voltage and current sampling circuit obtains the effective value i _r of the resonant current and the phase difference Δθ, the frequency control circuit of the wireless power supply system enters the main program operation stage: first, judge the detuning range of the resonant frequency according to the size of the phase difference Δθ; When -δ≤Δθ≤δ, only frequency tracking control is required to complete the frequency adjustment; when Δθ≤-δ or Δθ≥δ, the dynamic compensation tuning module circuit completes the control of the resonant capacitor at this time.

The above-mentioned dynamic compensation tuning module circuit is composed of a fuzzy controller, a gate drive circuit and a capacitor array, and the capacitor array is connected in parallel to the resonant compensation capacitor _CD at the receiving end.

The above-mentioned frequency tracking control module is composed of A/D conversion circuit, single-chip microcomputer, phase-locked loop and DDS waveform generator.

Using the self-tuning and frequency-stabilizing method of the self-tuning and frequency-stabilizing system of the above-mentioned high-voltage iron tower monitoring equipment wireless energy supply system, the steps of self-tuning and stabilizing the frequency are as follows:

Step1: Use the resonant voltage and current sampling circuit to collect the transmitter series resonant circuit voltage u(θ) _r and resonant current i(θ) _r respectively;

Step2: Amplify and filter the voltage and current signals respectively, and then input them into the phase detection circuit to obtain the working voltage u(θ) _r and the working current i(θ) _r of the wireless energy transfer resonant converter at this time Phase difference Δθ=u(θ) _r -i(θ) _r and the effective value i _r of the resonance current at this time;

Step3: Judge the working state of the wireless energy transfer device; when the phase difference Δθ=0, it means that the wireless energy transfer link is in a resonant state, and there is no need to tune and stabilize the frequency; when Δθ≠0, it means that the wireless energy transfer link is in failure In the harmonic state, the resonance frequency needs to be adjusted;

Step4: Judging the detuning range of the resonant frequency; when the phase difference of the wireless energy transfer system Δθ≤--δ or Δθ≥δ, the system enters a tuning process, that is, dynamically compensates the capacitance, and needs to adjust the working frequency of the wireless energy transfer device Perform large-scale coarse adjustment;

Step5: When -δ≤Δθ≤δ, it means that the working frequency fluctuation range of the wireless energy transmission device is small at this time, and it only needs to be tuned within a small range;

Step6: After completing Step5, the controller unit will control the DDS waveform generator to generate the corresponding PFM pulse signal according to the calculated value of the phase-locked loop, thereby controlling the conduction of the MOSFET tube of the inverter, thereby changing the operation of the switching tube of the resonant converter Frequency, to complete the frequency tuning of the wireless energy transfer system.

The specific implementation process of the above-mentioned Step4 is as follows:

Step4.1: When Δθ≤-δ or Δθ≥δ, first input the detected current effective value I _i and phase difference Δθ into the fuzzy controller, and use the current effective value and phase difference Δθ as the input variables of the fuzzy controller ;

Step4.2: According to fuzzy inference rules, fuzzy quantization of current effective value i _r and phase difference Δθ is converted into a fuzzy vector;

Step4.3: Carry out logical reasoning and decision-making according to fuzzy reasoning and fuzzy rules, and send the result of reasoning to the defuzzification interface for defuzzification processing;

Step4.4: Combine the fuzzy processing results with the fuzzy calculation rules and the following formula to obtain the capacitance compensation amount:

Step4.5: According to the compensation amount ΔC _eq , the control circuit controls the opening and closing of the switch in the dynamic compensation circuit, so as to realize the preliminary frequency modulation of the working frequency of the entire wireless power supply system.

The specific implementation process of the above-mentioned Step4 is as follows:

Step5.1: When -δ≤Δθ≤δ, then the detected working AC voltage u(θ) _r and current i(θ) _r are respectively processed by the processing circuit to perform an A/D conversion;

Step5.2: Input the signal obtained by the converter into the single-chip microcomputer, and the single-chip microcomputer realizes the closed-loop frequency tracking through the phase-locked loop;

Step5.3: Control the DDS waveform generator to generate high-frequency PWM signals;

Step5.4: Then the PWM driver controls the on-off of the MOS tube, so that the switching frequency of the MOS tube follows the change of the resonant frequency of the compensation circuit of the resonant converter, thereby realizing a more precise tuning operation.

The invention provides an autonomous tuning and frequency stabilization system and method for a wireless energy supply system for high-voltage iron tower monitoring equipment. The wireless energy supply device can be divided into two parts: "energy acquisition" and "energy transmission" according to its functions; the "energy acquisition" part , that is, the high-voltage transmission line induction energy harvesting device; its function is: first, according to Faraday’s electromagnetic induction, through the energy harvesting coil, the magnetic field energy changing near the transmission wire can be converted into a corresponding low-frequency alternating current, and then passed through the full bridge rectifier circuit. It is converted into DC current and stored in the battery for the needs of the subsequent circuit; the other part is the "energy transmission" part, which is the magnetic coupling resonance wireless energy transmission device; in order to maintain the high insulation of the transmission line, it is impossible The electric energy stored in the battery is transmitted to the load equipment erected on the high-voltage iron tower through wires; therefore, the collected electric energy is transmitted to the online monitoring equipment on the iron tower in a wireless way. The wireless energy transmission device is also composed of two parts: an energy transmitting device and an energy receiving device. The energy transmitting device is an energy conversion device with a high-frequency inverter circuit and a transmitting coil as the core. Its function is to convert the direct current stored in the battery into tens or even hundreds of hertz of high-frequency through the high-frequency inverter circuit. alternating current. And form a mutually coupled powerful electromagnetic field in the air through the sending and receiving coils. The energy receiving device uses magnetic resonance to generate high-frequency alternating current in the receiving coil with the same frequency as that flowing through the transmitting coil. Then, through a specific rectification and voltage stabilization link, the high-frequency power is converted into the 12V/24V/36V DC power required by the online monitoring equipment, so as to supply the load.

The present invention has following beneficial effect:

1. The control object of the present invention is a wireless energy supply system for high-voltage iron tower monitoring equipment. Compared with the traditional new energy power supply system, the wireless energy supply system can greatly reduce the consumption of fossil energy, improve energy efficiency, and at the same time Can reduce environmental pollution.

2. The self-tuning and frequency stabilization strategy of the wireless energy supply system for high-voltage iron tower monitoring equipment designed by the present invention has a relatively large working range and a wide range of applications. And it is not very sensitive to the change of the characteristic parameters of the controlled object, thus greatly improving the robustness of the control mode designed in the present invention.

3. The self-tuning and frequency stabilization strategy for the wireless energy supply system of the high-voltage iron tower monitoring equipment provided by the present invention does not need to contain too complicated control theory knowledge, so that the designed algorithm is relatively simple, and the obtained main program is easy to implement. It is also very convenient and fast, which is convenient for the popularization and popularization of the control strategy designed in the present invention.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention will be further described:

Fig. 1 is the distribution diagram of the wireless energy supply device of the high-voltage iron tower monitoring equipment of the present invention;

Fig. 2 is a detailed architecture diagram of the wireless energy supply system of the high-voltage iron tower monitoring equipment of the present invention;

Fig. 3 is a schematic diagram of the self-tuning frequency stabilization control of the wireless energy supply system of the high-voltage iron tower monitoring equipment of the present invention;

Figure 4 is the main program flow chart;

Fig. 5 is a schematic diagram of the capacitor array structure;

Figure 6 is a simulation diagram of the wireless energy supply system;

Figure 7 is the simulation output waveform of the wireless energy supply system based on the self-tuning frequency stabilization strategy

Figure 8 shows the output characteristics of the wireless energy supply system under different control strategies.

Detailed ways

The technical solution of the present invention will be described in detail below in conjunction with the drawings and embodiments.

As shown in Figure 1-3, the self-tuning frequency stabilization system of the wireless energy supply system of the high-voltage iron tower monitoring equipment. The wireless energy supply system of the high-voltage iron tower monitoring equipment includes an energy harvesting device and a magnetic coupling resonance wireless energy transmission device. The energy harvesting device includes The energy-taking coil, the transmission line passes through the energy-taking coil, and converts the changing magnetic field energy near the transmission wire into corresponding low-frequency alternating current, and then passes through the full-bridge rectifier circuit to convert it into direct current and store it in the battery for subsequent stage circuit required;

The magnetically coupled resonant wireless energy transmission device consists of two parts: an energy transmitting device and an energy receiving device. The energy transmitting device is an energy conversion device including a high-frequency inverter circuit and a transmitting coil, and converts the direct current stored in the battery through high-frequency inverter The circuit converts high-frequency alternating current and forms a mutually coupled electromagnetic field in the air through the receiving coil;

The energy receiving device uses magnetic resonance to generate high-frequency alternating current with the same frequency as that flowing through the transmitting coil inside the receiving coil, and then converts the high-frequency power into the direct current required by the online monitoring equipment through the rectification and voltage stabilization link, thereby supplying direct current load usage.

The circuit of the wireless energy supply system of the above-mentioned high-voltage iron tower monitoring equipment includes the main circuit of the wireless power supply system and the frequency control circuit;

_The main circuit of _the wireless power supply _system is composed of two parts: the induction energy harvesting circuit and the _wireless energy transmission circuit. Energy harvesting is carried out on L ₁ , _ip is the current flowing through the transmission wire, V _S is the output voltage of the power harvesting coil, and the output terminals of the full-bridge rectifier D ₁ ~ D ₄ are connected to the filter capacitor C _1n of the transmitter.

The above-mentioned wireless energy transmission circuit adopts a double-coil series topology main circuit structure, which is composed of a full-bridge inverter, a series resonant circuit at the transmitting end, a series resonant circuit at the receiving end, and a full-bridge rectifier circuit. The induction energy-taking circuit outputs a direct current i _dc Output to the full-bridge inverters S ₁ ~ S ₄ , the output terminals of the full-bridge inverters S ₁ ~ S ₄ are connected to the series resonant circuit of the transmitting end, the series resonant circuit of the transmitting end includes the inductance L _T of the transmitting coil in series, the parasitic The resistance r _T and the resonant compensation capacitor C _T at the transmitting end, the series resonant circuit at the receiving end includes a series receiving coil inductance _LD , the parasitic resistance r _D of the receiving circuit and the resonant compensation capacitor C _D at the receiving end, the receiving coil inductance _LD and the transmitting coil inductance Corresponding to L _T , _{i r} and i _D are the high-frequency resonant currents _{of the} transmitting _end and the receiving end respectively. The end is connected to the receiving end filter capacitor C _2n .

The above-mentioned frequency control circuit includes a resonance voltage and current sampling circuit, a dynamic compensation tuning module circuit and a frequency tracking control module circuit;

The resonant voltage and current sampling circuit completes the detection of the voltage u(θ) _r and the resonant current i(θ) _r of the series resonant circuit at the transmitting end, and then passes u(θ) _r and i(θ) _r through the proportional amplifier and the difference At the same time, use the corresponding band-pass filter to filter out the redundant harmonic components, and then use the phase detection circuit and the current effective value detection circuit to obtain the resonance current at this time from the obtained pure resonance voltage and current components. Effective value i _r and phase difference Δθ.

After the above-mentioned resonant voltage and current sampling circuit obtains the effective value of the resonant current and the phase difference Δθ, the frequency control circuit of the wireless power supply system enters the main program operation stage: first, judge the detuning range of the resonant frequency according to the size of the phase difference Δθ; when- When δ≤Δθ≤δ, only frequency tracking control is required to complete the frequency adjustment; when Δθ≤-δ or Δθ≥δ, the dynamic compensation tuning module circuit completes the control of the resonant capacitor at this time.

The above-mentioned dynamic compensation tuning module circuit is composed of a fuzzy controller, a gate drive circuit and a capacitor array, and the capacitor array is connected in parallel to the resonant compensation capacitor _CD at the receiving end.

The above-mentioned frequency tracking control module is composed of A/D conversion circuit, single-chip microcomputer, phase-locked loop and DDS waveform generator.

Using the self-tuning and frequency-stabilizing method of the self-tuning and frequency-stabilizing system of the above-mentioned high-voltage iron tower monitoring equipment wireless energy supply system, the steps of self-tuning and stabilizing the frequency are as follows:

Step1: Use the resonant voltage and current sampling circuit to collect the transmitter series resonant circuit voltage u(θ) _r and resonant current i(θ) _r respectively;

Step2: Amplify and filter the voltage and current signals respectively, and then input them into the phase detection circuit to obtain the working voltage u(θ) _r and the working current i(θ) _r of the wireless energy transfer resonant converter at this time Phase difference Δθ=u(θ) _r -i(θ) _r and the effective value i _r of the resonance current at this time;

Step3: Judge the working state of the wireless energy transfer device; when the phase difference Δθ=0, it means that the wireless energy transfer link is in a resonant state, and there is no need to tune and stabilize the frequency; when Δθ≠0, it means that the wireless energy transfer link is in failure In the harmonic state, the resonance frequency needs to be adjusted;

Step4: Judging the detuning range of the resonant frequency; when the phase difference of the wireless energy transfer system Δθ≤--δ or Δθ≥δ, the system enters a tuning process, that is, dynamically compensates the capacitance, and needs to adjust the working frequency of the wireless energy transfer device Perform large-scale coarse adjustment;

Step5: When -δ≤Δθ≤δ, it means that the working frequency fluctuation range of the wireless energy transmission device is small at this time, and it only needs to be tuned within a small range;

Step6: After completing Step5, the controller unit will control the DDS waveform generator to generate the corresponding PFM pulse signal according to the calculated value of the phase-locked loop, thereby controlling the conduction of the MOSFET tube of the inverter, thereby changing the operation of the switching tube of the resonant converter Frequency, to complete the frequency tuning of the wireless energy transfer system.

The specific implementation process of the above-mentioned Step4 is as follows:

Step4.1: When Δθ≤--δ or Δθ≥δ, first input the detected current effective value I _i and phase difference Δθ into the fuzzy controller, and use the current effective value and phase difference Δθ as the input of the fuzzy controller variable;

Step4.2: According to fuzzy inference rules, fuzzy quantization of current effective value i _r and phase difference Δθ is converted into a fuzzy vector;

Step4.3: Carry out logical reasoning and decision-making according to fuzzy reasoning and fuzzy rules, and send the result of reasoning to the defuzzification interface for defuzzification processing;

Step4.4: Combine the fuzzy processing results with the fuzzy calculation rules and the following formula to obtain the capacitance compensation amount:

Step4.5: According to the compensation amount ΔC _eq , the control circuit controls the opening and closing of the switch in the dynamic compensation circuit, so as to realize the preliminary frequency modulation of the working frequency of the entire wireless power supply system.

The specific implementation process of the above-mentioned Step4 is as follows:

Step5.1: When -δ≤Δθ≤δ, then the detected working AC voltage u(θ) _r and current i(θ) _r are respectively processed by the processing circuit to perform an A/D conversion;

Step5.2: Input the signal obtained by the converter into the single-chip microcomputer, and the single-chip microcomputer realizes the closed-loop frequency tracking through the phase-locked loop;

Step5.3: Control the DDS waveform generator to generate high-frequency PWM signals;

Step5.4: Then the PWM driver controls the on-off of the MOS tube, so that the switching frequency of the MOS tube follows the change of the resonant frequency of the compensation circuit of the resonant converter, thereby realizing a more precise tuning operation.

Example:

The control object designed and controlled by the present invention is the wireless energy supply system of the high-voltage iron tower online monitoring equipment, and the specific structure of the wireless energy supply device is shown in Figure 1 and Figure 2 .

The wireless energy supply device can be divided into two parts according to its functions: "energy acquisition" and "energy transmission". The "energy harvesting" part is the induction energy harvesting device of the high-voltage transmission line; its function is: first, according to Faraday's electromagnetic induction, through the energy harvesting coil, the magnetic field energy changing near the transmission wire can be converted into a corresponding low-frequency alternating current, and then through the whole The bridge rectifier circuit converts it into DC current and stores it in the battery for the subsequent circuit; the other part is the "energy transmission" part, which is the magnetic coupling resonance wireless energy transmission device. In order to maintain the high insulation of the transmission line, it is impossible to transmit the electric energy stored in the battery to the load equipment erected on the high-voltage iron tower through wires; therefore, the collected electric energy is transmitted to the online on-line Monitoring equipment; the wireless energy transmission device is also composed of an energy transmitting device and an energy receiving device; the energy transmitting device is an energy conversion device with a high-frequency inverter circuit and a transmitting coil as the core, and its function is to store The direct current is converted into tens or even hundreds of hertz of high-frequency alternating current by a high-frequency inverter circuit; and a strong electromagnetic field coupled with each other is formed in the air through the sending and receiving coils; and the energy receiving device uses magnetic resonance In this way, a high-frequency alternating current with the same frequency as that flowing through the transmitting coil is generated inside the receiving coil. Then, through a specific rectification and voltage stabilization link, the high-frequency power is converted into the 12V/24V/36V DC power required by the online monitoring equipment, so as to supply the load.

Further, in order to facilitate the analysis of frequency detuning characteristics: analyze the main circuit of the wireless energy supply system of the high-voltage iron tower monitoring equipment in Figure 3:

when , the resonant network is in a resonant state, and the coil loop is purely resistive; when ω>ω ₀ , the resonant network is in an over-resonant state, and the loop is inductive; when ω<ω ₀ , the resonant network is in an under-resonant state, and the coil loop is Capacitance.

When the wireless energy transmission link is in the resonant working state, the equivalent impedance of the coil loop is the smallest, and the wireless power supply system can work at the maximum efficiency state; in the non-resonant state, the greater the frequency offset range, the greater the working efficiency of the wireless power supply system Therefore, real-time frequency adjustment is required for the wireless energy transmission link.

Referring to Fig. 3, the circuit of the wireless energy supply system for the monitoring equipment of the high-voltage iron tower includes two parts: the main circuit of the wireless power supply system and the auxiliary circuit for frequency control.

Specifically: combined with Figure 3, the main circuit of the wireless energy supply system is mainly composed of an induction energy acquisition circuit and a wireless energy transmission circuit.

The induction energy harvesting circuit mainly consists of an energy harvesting coil and a full-bridge rectifier circuit; among them, _ip is the current flowing through the transmission wire, V _S is the output voltage of the energy harvesting coil, D ₁ ~ D ₄ constitute a full-bridge rectifier circuit, and C _n It is a filter capacitor, mainly to filter out the AC component of the rectifier circuit, and at the same time play a role in stabilizing the voltage.

The wireless energy transmission circuit adopts a typical double-coil series topology main circuit structure, which is mainly composed of a full-bridge inverter, a series resonant circuit at the transmitting end, a series resonant circuit at the receiving end, and a full-bridge rectifier circuit; among them, i _dc is the energy harvesting device Output direct current, C _1n is the power supply filter capacitor, S ₁ ~ S ₄ constitutes a full-bridge inverter, L _T is the inductance of the transmitting coil, L _D is the inductance of the receiving coil, C _T and _CD are the corresponding resonances of the transmitting end and the receiving end Compensation capacitance, i _r , i _D are the high-frequency resonance currents of the transmitting end and receiving end respectively, r _T , rD are the parasitic resistances of the transmitting circuit and receiving circuit respectively, S ₅ ~ S ₈ form a full-bridge rectifier, and C _2n is a rectifier bridge The filter capacitor uses its charge and discharge function to make the output voltage U _OUT tend to be smooth.

Referring to Fig. 3, the auxiliary control circuit of the wireless energy supply system includes a resonant voltage and current sampling circuit, a dynamic compensation tuning module circuit and a frequency tracking control module circuit.

Among them, the resonant voltage and current sampling circuit completes the detection of the resonant voltage u(θ _{) r} and the resonant current i(θ _{) r} at the transmitting end of the main circuit of the wireless energy transfer system; The numerical amplification is carried out through the proportional amplifier and the differential amplifier, and the redundant harmonic components are filtered out by the corresponding band-pass filter. Then use the phase detection circuit and current effective value detection circuit to obtain the effective value and phase difference Δθ of the resonance current at this time by using the obtained pure resonance voltage and current components.

When the resonant voltage and current sampling circuit obtains the effective value of the resonant current and the phase difference Δθ, the auxiliary control circuit of the wireless energy supply system will enter the main program running stage, and the main program flow is shown in Figure 4.

With reference to Fig. 4, the main program flow of the control circuit is as follows: firstly, the detuning range of the resonant frequency is judged according to the magnitude of the phase difference Δθ. When -δ≤Δθ≤δ, it means that the working frequency fluctuation range of the wireless energy transfer device is small at this time, and it only needs to perform frequency modulation within a small range, that is, only frequency tracking control is required to complete the frequency adjustment; when Δθ When ≤-δ or Δθ≥δ, it means that the operating frequency fluctuation range of the wireless energy transmission device is relatively large at this time, and a large-scale frequency rough adjustment is required first. At this time, the dynamic compensation tuning module circuit completes the control of the resonant capacitor.

The dynamic compensation tuning module circuit in Fig. 3 is composed of fuzzy controller, gate drive circuit and corresponding capacitor array.

Firstly, input the detected voltage and current into the fuzzy controller, and use it as the input variable of the fuzzy controller; the fuzzy controller converts the error and its error rate of change into a fuzzy vector, and performs logical reasoning according to fuzzy reasoning and fuzzy rules And decision-making, send the result of reasoning (at this time, it is still a fuzzy vector, which cannot be directly used as a control quantity) to the defuzzification interface for defuzzification processing, calculate the approximate required compensation amount, and control the dynamics by the control circuit according to the compensation amount The opening and closing of the switch in the compensation circuit adjusts the frequency of the whole system when it is working.

Figure 5 is a schematic diagram of the capacitor array structure: wherein, the capacitor array is composed of two units with the same structure, and each unit is composed of five equal-sized capacitors and four bidirectional switch tubes, and the capacitance values in unit 1 and unit 2 are Set to C ₁ and C ₂ respectively; since the wireless energy transmission system has a relatively high operating frequency, and the switching loss of the switch tube is proportional to the frequency, in order to reduce the conduction power loss when the switch tube is turned on, the conduction of the capacitor array is set The principle is that each unit only allows one or two switches to conduct at a time. According to different combinations of switch tubes, and considering the principle that switches S ₁ and S ₂ , S ₅ and S ₆ cannot be turned on at the same time (otherwise there will be repetition of capacitor combinations), the resonant capacitor array can equivalently output 29 groups of different sizes Capacitance value, set the equivalent capacitance value of this capacitor array as C _eq .

The different equivalent capacitance values and corresponding switching sequences are as follows:

The frequency tracking control module circuit in Fig. 3 is composed of A/D conversion circuit, single-chip microcomputer, phase-locked loop and DDS waveform generator.

Mainly, the detected resonant AC voltage and current are respectively processed by the processing circuit to perform an A/D conversion. Afterwards, the signal from the converter is input to the single-chip microcomputer, and the single-chip microcomputer realizes closed-loop frequency tracking through a phase-locked loop, and controls the DDS waveform generator to generate high-frequency PWM signals, and then the PWM driver controls the on-off of the MOS tube, so that The switching frequency of the MOS tube follows the change of the resonant frequency of the compensation circuit of the resonant converter, thereby realizing more precise tuning operation.

Using the self-tuning and frequency-stabilizing method of the self-tuning and frequency-stabilizing system of the above-mentioned high-voltage iron tower monitoring equipment wireless energy supply system, the steps of self-tuning and stabilizing the frequency are as follows:

Step1: Use the current and voltage acquisition circuit to collect the resonant voltage u(θ) _r and the resonant current i(θ) _r of the resonant compensation circuit of the transmitting coil respectively;

Step2: Since the voltage and current signals are relatively small and contain a large number of high-order harmonics at this time, they need to be amplified and filtered separately. Then input them into the phase detection circuit respectively to obtain the phase difference between the working voltage u(θ) _r and the working current i(θ) _r of the wireless power transmission resonant converter at this time Δθ=u(θ) _r -i(θ ) _r and the effective value ir of the resonant current at this time;

Step3: Judge the working status of the wireless energy transfer device. When the phase difference Δθ=0, it means that the wireless energy transmission link is in a resonant state, and tuning and frequency stabilization is not required; when Δθ≠0, it means that the wireless energy transmission link is in a detuned state, and the resonance frequency needs to be adjusted;

Step4: Judging the detuning range of the resonant frequency; when the phase difference of the wireless energy transfer system is Δθ≤-δ or Δθ≥δ, the system enters a tuning process, that is, the capacitance is dynamically compensated, and the working frequency of the wireless energy transfer device needs to be adjusted. Coarse adjustment in a large range;

Step5: When -δ≤Δθ≤δ, it means that the working frequency fluctuation range of the wireless energy transmission device is small at this time, and it only needs to be tuned within a small range;

Step6: After completing Step5, the controller unit will control the DDS waveform generator to generate the corresponding PFM pulse signal according to the calculated value of the phase-locked loop, thereby controlling the conduction of the MOSFET tube of the inverter, thereby changing the operation of the switching tube of the resonant converter Frequency, to complete the frequency tuning of the wireless energy transmission system;

Further, the specific implementation process of the Step4 is as follows:

Step4.1: When Δθ≤-δ or Δθ≥δ, first input the detected current effective value i _r and phase difference Δθ into the fuzzy controller, and use the current effective value and phase difference Δθ as the input variables of the fuzzy controller ;

Step4.2: According to fuzzy inference rules, fuzzy quantization of current effective value Ii and phase difference Δθ is converted into a fuzzy vector;

Step4.3: Carry out logical reasoning and decision-making according to fuzzy reasoning and fuzzy rules, and send the result of reasoning (still a fuzzy vector at this time, which cannot be directly used as a control quantity) to the defuzzification interface for defuzzification processing; Step4.4: According to the fuzzy calculation rules, the fuzzy processing result is combined with the following formula to obtain the capacitance compensation amount:

Step4.5: According to the compensation amount ΔC _eq , the control circuit controls the opening and closing of the switch in the dynamic compensation circuit, so as to realize the preliminary frequency modulation of the working frequency of the entire wireless power supply system.

Further, the concrete realization process of described Step6 is as follows:

Step5.1: When -δ≤Δθ≤δ, then the detected working AC voltage U _i and current I _i are respectively processed by the processing circuit to perform an A/D conversion;

Step5.2: Afterwards, the signal obtained by the converter is input to the single-chip microcomputer, and the single-chip microcomputer realizes closed-loop frequency tracking through a phase-locked loop.

Step5.3: And control the DDS waveform generator to generate high frequency PWM signal;

Step5.4: Then the PWM driver controls the on-off of the MOS tube, so that the switching frequency of the MOS tube follows the change of the resonant frequency of the compensation circuit of the resonant converter, thereby realizing a more precise tuning operation.

In order to verify the effectiveness of the method of the present invention, a simulation experiment has also been carried out; the simulation circuit diagram of the wireless energy supply system is as shown in Figure 6; the resonant current obtained, the output voltage and current output waveform are as shown in Figure 7; the simulation results show that the present invention The self-tuning and frequency stabilization strategy of the designed wireless energy supply system, according to the phase difference of the resonant voltage and current, reasonably selects different control methods for tuning, thus maintaining the resonant working state of the wireless energy supply simulation system; Figure 8 shows different control strategies Compared with the traditional fixed-frequency control strategy, the self-tuning frequency stabilization strategy of the wireless energy supply system proposed by the present invention can greatly improve the stability of the wireless power supply mode.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions recorded in the above-mentioned embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (10)

1. The autonomous tuning frequency stabilization system of the wireless energy supply system of the high-voltage iron tower monitoring equipment is characterized in that the wireless energy supply system of the high-voltage iron tower monitoring equipment comprises an energy taking device and a magnetic coupling resonance type wireless energy transfer device, the energy taking device comprises an energy taking coil, a transmission line penetrates through the energy taking coil, magnetic field energy changing nearby the transmission line is converted into corresponding low-frequency alternating current, and then the corresponding low-frequency alternating current is converted into direct current through a full-bridge rectifying circuit and stored in a storage battery for being needed by a later-stage circuit;

the magnetic coupling resonance type wireless energy transmission device consists of an energy emission device and an energy receiving device, wherein the energy emission device is an energy conversion device comprising a high-frequency inverter circuit and an emission coil, and is used for converting direct current stored in a storage battery into high-frequency alternating current through the high-frequency inverter circuit and forming an electromagnetic field which is mutually coupled in the air through the receiving coil;

the energy receiving device generates high-frequency alternating current with the same frequency as that of the transmitting coil in the receiving coil by utilizing magnetic resonance, and then converts the high-frequency electric energy into direct current required by the on-line monitoring equipment through a rectifying and voltage stabilizing link, so that the direct current is supplied to a direct current load.

2. The autonomous tuning frequency stabilization system of the wireless power supply system of the high-voltage iron tower monitoring equipment according to claim 1, wherein the circuit of the wireless power supply system of the high-voltage iron tower monitoring equipment comprises a wireless power supply system main circuit and a frequency control circuit;

the main circuit of the wireless power supply system consists of an induction energy-taking circuit and a wireless energy-transferring circuit, wherein the induction energy-taking circuit comprises an energy-taking coil L ₂ And full bridge rectification D ₁ ～D ₄ Circuit assembly, energy-taking coil L ₂ By transmission of electricity to conduct L ₁ Energy taking on the upper part, i _p To obtain current for the transmission wire, V _S Full bridge rectifier D for taking energy coil output voltage ₁ ～D ₄ The output end is connected with the filter capacitor C of the transmitting end _1n 。

3. The autonomous tuning frequency stabilization system of the wireless energy supply system of the high-voltage iron tower monitoring equipment according to claim 2, wherein the wireless energy transfer circuit adopts a double-coil serial topology main circuit structure and consists of a full-bridge inverter, a transmitting end serial resonance circuit, a receiving end serial resonance circuit and a full-bridge rectification circuit, and the induction energy taking circuit outputs direct current i _dc Output to full bridge inverter S ₁ ～S ₄ Full bridge inverter S ₁ ～S ₄ The output end is connected with a transmitting end series resonant circuit which comprises a transmitting coil inductance L connected in series _T Parasitic resistance r of transmitting circuit _T Transmitting end resonance compensation capacitor C _T The receiving end series resonant circuit comprises a receiving coil inductance L connected in series _D Parasitic resistor r of receiving circuit _D And a receiving end resonance compensation capacitor C _D Is connected withWinding inductance L _D Inductance L with transmitting coil _T Corresponding, i _r 、i _D The high-frequency resonant current is respectively a transmitting end and a receiving end, and two ends of the receiving end series resonant circuit are connected with a full-bridge rectifying circuit S ₅ ～S ₈ Full bridge rectifier circuit S ₅ ～S ₈ The output end is connected with the filter capacitor C of the receiving end _2n 。

4. The autonomous tuning frequency stabilization system of the wireless energy supply system of the high-voltage tower monitoring equipment according to claim 3, wherein the frequency control circuit comprises a resonance voltage and current sampling circuit, a dynamic compensation tuning module circuit and a frequency tracking control module circuit;

the resonant voltage and current sampling circuit is used for completing the series resonant circuit voltage u (theta) of the transmitting end _r And resonance current i (θ) _r Will then be u (θ) respectively _r And i (θ) _r The harmonic component is filtered by a corresponding band-pass filter, and then the obtained harmonic voltage current fundamental component is used for obtaining the effective value i of the harmonic current at the moment by a phase detection circuit and a current effective value detection circuit _r And a phase difference delta theta.

5. The autonomous tuning frequency stabilization system of the wireless power supply system of the high-voltage tower monitoring device according to claim 4, wherein after the effective value of the resonance current and the phase difference delta theta are obtained by the resonance voltage current sampling circuit, the frequency control circuit of the wireless power supply system enters a main program operation stage: firstly, judging a resonance frequency detuning range according to the magnitude of a phase difference delta theta; when delta is less than or equal to delta and less than or equal to delta, frequency adjustment can be completed only by frequency tracking control; when delta theta is less than or equal to minus delta or delta theta is more than or equal to delta, the dynamic compensation tuning module circuit finishes the control of the resonance capacitance.

6. The autonomous tuning frequency stabilization system of a wireless power supply system for a high-voltage tower monitoring device of claim 5, wherein theThe dynamic compensation tuning module circuit of the (C) is composed of a fuzzy controller, a gate electrode driving circuit and a capacitor array, wherein the capacitor array is connected in parallel with a receiving end resonance compensation capacitor C _D And (3) upper part.

7. The system of claim 6, wherein the frequency tracking control module comprises an a/D conversion circuit, a single-chip microcomputer, a phase-locked loop, and a DDS waveform generator.

8. An autonomous tuning and stabilizing method of an autonomous tuning and stabilizing system of a wireless energy supply system of a high-voltage iron tower monitoring device according to the above claim 7, characterized in that the autonomous tuning and stabilizing method comprises the following steps:

step1: the voltage u (theta) of the transmitting end series resonance circuit is respectively acquired by utilizing a resonance voltage and current sampling circuit _r And resonance current i (θ) _r ；

Step2: the voltage and current signals are respectively amplified and filtered, and then are respectively input into a phase detection circuit to obtain the working voltage u (theta) of the wireless energy-transfer resonant converter at the moment _r And operating current i (θ) _r Phase difference Δθ=u (θ) _r -i(θ) _r Effective value i of resonant current at this time _r ；

Step3: judging the working state of the wireless energy transmission device; when the phase difference delta theta=0, the wireless energy transmission link is in a resonance state, and tuning and frequency stabilization are not needed; when delta theta is not equal to 0, the wireless energy transmission link is in a detuned state, and the resonant frequency needs to be adjusted;

step4: judging the detuning range of the resonant frequency; when the phase difference delta theta is less than or equal to minus delta or delta theta is more than or equal to delta, the system enters a one-time tuning process, namely, the capacitance is dynamically compensated, and the working frequency of the wireless energy transmission device needs to be coarsely adjusted in a large range;

step5: when delta is less than or equal to delta and less than or equal to delta, the fluctuation range of the working frequency of the wireless energy transmission device is smaller, and only frequency modulation in a small range is needed;

step6: after Step5 is completed, the controller unit controls the DDS waveform generator to generate a corresponding PFM pulse signal according to the calculated value of the phase-locked loop, so as to control the MOSFET of the inverter to be conducted, thereby changing the working frequency of the switching tube of the resonant converter and completing the frequency tuning of the wireless energy transmission system.

9. The method for self-tuning and frequency stabilization of the wireless energy supply system of the high-voltage iron tower monitoring equipment according to claim 8, wherein the specific implementation process of Step4 is as follows:

step4.1: when delta theta is less than or equal to minus delta or delta theta is more than or equal to delta, firstly, the detected current effective value I _i And the phase difference delta theta are input into a fuzzy controller, and the current effective value i is input _r And the phase difference delta theta as input variables of the fuzzy controller;

step4.2: according to fuzzy reasoning rule, current effective value i _r And the phase difference delta theta is subjected to fuzzy quantization and converted into a fuzzy vector;

step4.3: carrying out logic reasoning and decision according to the fuzzy reasoning and the fuzzy rule, and sending the reasoning result to a defuzzification interface for defuzzification processing;

step4.4: and obtaining capacitance compensation quantity according to a fuzzy calculation rule by combining the following formula with a fuzzy processing result:

step4.5: according to the compensation quantity delta C _eq The opening and closing of the switch in the dynamic compensation circuit are controlled by the control circuit, so that the primary frequency modulation of the working frequency of the whole wireless power supply system is realized.

10. The method for self-tuning and frequency stabilization of the wireless energy supply system of the high-voltage iron tower monitoring equipment according to claim 9, wherein the specific implementation process of Step4 is as follows:

step5.1: when delta is less than or equal to delta and less than or equal to delta, then the detected working alternating current resonance is further detectedVoltage u (theta) _r Current i (θ) _r Respectively processing the signals by a processing circuit and then performing primary A/D conversion;

step5.2: inputting the signals obtained by the converter into a singlechip, and realizing closed-loop frequency tracking by the singlechip through a phase-locked loop;

step5.3: controlling the DDS waveform generator to generate a high-frequency PWM signal;

step5.4: and then the PWM driver controls the on-off of the MOS tube, so that the switching frequency of the MOS tube follows the change of the resonant frequency of the compensation circuit of the resonant converter, and more accurate tuning operation is realized.