Summary:
In order to solve the problem that in some non-contact power transmission processes, signals can only be transmitted in one direction or half-duplex, and real-time interaction of signal control and feedback cannot be realized, the full-duplex transmission of signals in inductively coupled power transmission (ICPT) systems is aimed at The problem is to propose a method to change the amplitude of the input voltage through the gate switch for signal forward transmission, and adjust the secondary side compensation capacitor for signal reverse transmission. Analyzed the influence of the input voltage amplitude change on the secondary side current and the secondary side compensation capacitor change on the primary side current, and used Simulink, Simplorer and Maxwell joint simulation to obtain the primary and secondary side current envelope when the input voltage and the secondary side compensation capacitor change at the same time Information and simulation results verify the feasibility of signal full-duplex transmission.
0 Preface
Inductively Coupled Power Transmission (ICPT), as a new type of wireless power transmission technology, overcomes the hidden safety hazards and functional limitations of traditional power transmission through wires [1]. However, in many practical applications, it is not only necessary to meet the transmission requirements of electric energy, but also to realize the real-time transmission of signals. For example, in special application environments such as oil drilling and built-in medical electronic devices, while completing energy transfer, it is not only necessary to continuously send control instructions from the primary side to the secondary side, but also to feed back the information monitored by the secondary side in real time. Original side.
In many previous researches on ICPT system signal transmission, an additional pair of signal coupling coils is often used to separate the signal and energy. This not only increases the complexity of the system design, but there is also interference between the energy coil and the signal coil. problem. Or only the one-way transmission mode in which the signal is transmitted from the primary side of the system to the secondary side or the secondary side is transmitted to the primary side is studied [2-8]. The existing method of signal transmission from the primary side to the secondary side mostly adopts the addition of switching devices in the main circuit of the system. When the switch is turned off, the energy stored in the inductance and capacitance in the circuit can only be relied on to supply power to the subsequent stage. The transmission speed is slow, and it can only work at low power.
Aiming at the problem of signal full-duplex transmission in the ICPT system, this paper proposes a method to select different amplitude input voltages for signal forward transmission through a gate switch, and adjust the secondary side compensation capacitor for signal reverse transmission, which not only greatly improves the transmission Speed, and realize the full-duplex transmission of the signal.
1 System structure and transmission principle
1.1 Principle of signal modulation
Figure 1 shows the schematic diagram of the ICPT system. The system can be divided into primary loop and secondary loop. The primary circuit inverts the DC voltage into a high frequency AC voltage through a converter, generates an alternating magnetic field on the primary side and couples it to the secondary side. The secondary side induces an electromotive force, which is compensated and rectified and filtered to provide electrical energy to the load.
A typical full-bridge inverter SP (the capacitor is connected in series with the primary in the circuit and the secondary is connected in parallel) type compensation circuit and its equivalent circuit are shown in Figure 2 and Figure 3.
The SP structure secondary impedance ZS can be written as:
In the case that the primary and secondary circuit parameters are constant, it can be seen from equation (5) that only changing the input voltage Vin will change the magnitude of the secondary current IS. From formula (1), formula (3), and formula (6), we can see that changing the capacitance of C2 will change the reflection impedance Zr of the secondary coil to the primary side, and then change the magnitude of the primary current amplitude IP.
Therefore, you can select the appropriate input voltage Vin and the adjustment capacitor C9, adjust the gate switch and the secondary side compensation capacitor according to different digital signals "0" or "1", and set the transmission speed from the secondary to the primary to be the primary to the secondary transmission. Twice the speed. It can be seen from equations (4) and (5) that if the parameters of the primary and secondary circuits do not change, the primary and secondary currents IP and IS will both change if the input voltage Vin is changed. When the capacitance value of C2 changes, the primary current amplitude IP changes relatively large, and the secondary current amplitude IS changes very small. Therefore, in addition to the amplitude change caused by its own change, the current on the primary and secondary side has another side change that affects it. Therefore, four currents with different amplitudes will be generated on the primary and secondary side. The signal is demodulated by detecting the envelope characteristics of the current amplitude of the primary and secondary side, so as to realize the signal full-duplex transmission.
1.2 Primary and secondary side modulation circuit
Based on the above derivation, the signal modulation mechanism is added to the primary and secondary sides of the ICPT system. As shown in Figure 4, the primary side modulation part is mainly composed of a boost circuit and strobe switches S1 and S2. When the digital signal "0" is transmitted, the strobe switch S2 is turned on, and the power supply voltage is directly obtained. When the digital signal "1" is transmitted, the strobe switch S1 is turned on to obtain the boosted voltage. By selecting different power supply voltage amplitudes, secondary current amplitudes with different amplitudes can be obtained. As shown in Figure 5, the secondary side modulation part is mainly composed of a common E-pole anti-series switch S3 and a modulation capacitor C9. When the digital signal "0" is transmitted, the switch S3 is turned off, the secondary compensation capacitor is C2, and the system is in a normal resonance state. When the digital signal "1" is transmitted, the switch S3 is turned on, the secondary compensation capacitor becomes C2+C9, and the impedance reflected to the primary side will change, thereby changing the current amplitude of the primary side. The amplitude envelope of the primary secondary current is demodulated to obtain the transmitted digital signal.
2 Loosely coupled transformer
Loosely coupled transformer is the core component of inductively coupled power transmission system. Due to the large air gap between the primary and secondary coils of the loosely coupled transformer, the magnetic leakage is obvious, resulting in low energy transmission capacity and efficiency. In order to reduce magnetic leakage, improve system transmission performance, and increase transmission efficiency, a barrel transformer is used in this article. The 2D and 3D models of the barrel transformer established in Maxwell are shown in Figure 6 and Figure 7.
The magnetic core is PC40, the inner magnetic barrel is the primary side of the transformer, and the 20-turn coil is wound close to the outer wall of the inner magnetic barrel; the outer magnetic barrel is the secondary side of the transformer, and the 21-turn coil is wound close to the inner wall of the outer magnetic barrel. The core size is shown in Table 1.
3 Simulink, Simplorer, Maxwell co-simulation
Simulink is used to generate two complementary PWM waves to control the mutual conduction of the full-bridge inverter. In the simulation, two power supply voltages with different amplitudes are directly selected, and digital signals "0" and "1" are randomly generated to control the primary side gate switch S1. S2 and the common E-pole anti-series switch S3, import the Maxwell transformer model into Simplorer, and perform overall simulation analysis on the full-bridge inverter SP compensation circuit. The simulation circuit is shown as in Fig. 8. The specific parameters of the simulation circuit are shown in Table 2.
According to the gating frequency of S1 and S2, it can be obtained that the primary transmits a digital signal every 400μs to the secondary. Figure 9 shows the voltage and current waveforms after the primary full-bridge inverter. It can be seen from the voltage envelope that the signal to be transmitted at the primary stage is "1011111". Figure 10 shows the secondary current. According to its envelope characteristics, the digital signal picked up by the secondary coil and transferred from the primary side to the secondary side is "1011111".
According to the gate frequency of S3, the primary transmits a digital signal every 200μs to the secondary. Figure 11 shows the voltage waveform of the adjustment capacitor C9. From the voltage envelope, it can be seen that the signal to be transmitted by the secondary is "10111111011101". Figure 12 shows the primary current. According to its envelope characteristics, the digital signal transmitted from the secondary side to the primary side can be obtained as "10111111011101".
The above simulation results show that the signal can be demodulated accurately by the current amplitude, and this method can realize the full-duplex transmission of the signal in the inductively coupled power transmission system.
4 Conclusion
This article analyzes the influence of the inductively coupled power transmission system input voltage amplitude and the secondary side compensation change on the system current amplitude. Aiming at the problem of signal full-duplex transmission in the ICPT system, a method of selecting input voltages of different amplitudes through the gate switch for signal forward transmission and adjusting the secondary side compensation capacitor for signal reverse transmission is proposed. System simulation was carried out to verify the feasibility of the method. This method provides a new method for signal full-duplex transmission in the ICPT system, solves the problem of real-time interaction between control signals and feedback signals in the process of non-contact power transmission, and has good practical value and application prospects.
Today let`s talk about touch screen laptop. Sometimes people take Yoga Laptop or 2 In 1 Laptop or 360 Laptop as foldable touch screen laptop. Cause the later ones usually with touch screen function. The difference is that touch screen laptop specials can`t be flipped up to 360 degree, usually 180 degree. Do you think which kind of person love 2 in 1 touch screen laptop more? Business people is the right answer, cause they care more performance, touch screen function, 180 rotating, which are the very important points for businessman, especially teaching in person, do presentation, etc.
Do you think what other business laptop businessman love also except touch screen laptop under 20000? 14 inch 11th Laptop and 15.6inch 11th or 10th Laptop should be the top levels.
As a professional manufacturer, also customizing Android Tablet, Mini PC , and all in one except laptop. So believe you can always get the most competitive one at this store, balancing the quality and cost at top.
Any other special demand, you can just contact us freely. Will try our best to back you up.
Touch Screen Laptop,Touch Screen Laptop Specials,Touch Screen Laptop Under 20000,Foldable Touch Screen Laptop,2 In 1 Touch Screen Laptop
Henan Shuyi Electronics Co., Ltd. , https://www.shuyiminipc.com