CN110233524B - Analog-controlled self-resonant, ultra-quiet wireless power supply system - Google Patents

Abstract

The invention relates to the field of electric energy transmission, and aims to realize automatic tracking of resonant frequency, improve power supply power and efficiency and reduce external electromagnetic interference. The self-resonance and ultra-silent wireless power supply system comprises a power supply, a choke coil, a capacitor, a transmitting coil, a magnetic core, a receiving coil, a full-wave rectifier bridge, a voltage stabilizing capacitor, a resonant capacitor, a coupler, a zero detection control chip and a switch, wherein the power supply is connected with a first pin of the choke coil, a second pin of the choke coil is connected with a first pin of the capacitor, and a second pin of the capacitor is grounded; the second pin of the choke coil is connected with the center tap of the transmitting coil, the transmitting coil is coupled with the receiving coil through the magnetic core, the receiving coil is connected with a full-wave rectifier bridge composed of diodes with the same model, and the output of the rectifier bridge is connected with a voltage stabilizing capacitor to supply power for a load. The invention is mainly applied to the design and manufacturing occasions of the ultra-silent wireless power supply system.

Description

Analog-controlled self-resonant, ultra-quiet wireless power supply system

Technical field

The present invention relates to the field of electric energy transmission, and in particular to the field of non-contact power supply.

Background technique

Rotary measurement equipment such as lidar systems and rotating machinery telemetry systems can achieve horizontal 360° scanning under working conditions. The traditional wire power supply method will have wire winding problems and cannot meet the power supply requirements. At the same time, the equipment generally rotates at a high speed under working conditions. If contact power supply such as slip rings, brushes, etc. is used for power supply, the service life of the system will be limited. According to literature reports, the service life of lidars powered by slip rings is Approximately one thousand hours and requires regular maintenance. In order to improve its service life, the power supply method should be non-contact power supply.

Common non-contact power supply methods include electromagnetic coupling resonance wireless power supply and inductive coupling wireless power supply. The advantage of magnetic coupling resonance wireless power supply is that it can transmit power to long distances, but the magnetic coupling resonance wireless power supply method has low efficiency and high electromagnetic interference. , and when the transmission power is large, the size of the coil is also large, which is not conducive to integration. At the same time, in the above application, the power supply distance is not large, about 1mm, so this system can further reduce the distance between the transmitting coil and the receiving coil and use inductive coupling instead.

When using inductive coupling for power supply, in order to increase the coupling coefficient, improve power supply efficiency, and reduce external electromagnetic interference, the magnetic lines generated by the magnetic core convergence coil should be introduced, and a current-type parallel resonant switching power supply should be used to make the circuit work in the circuit at the natural frequency. The circuit designed based on the above principles is called an ultra-quiet converter due to its low interference characteristics. However, in the application of power supply for rotating equipment, the coil distance will produce slight changes. Due to the introduction of the magnetic core, the transmitting coil and the receiving coil are between tight coupling and loose coupling. These small distance changes will affect the resonant frequency of the system, causing The system cannot work in the resonance state for a long time. Traditional silent converters generally work under static conditions and cannot achieve frequency tracking. In order to make up for this shortcoming, a frequency tracking system should be added to improve the traditional silent converter into a self-resonant, ultra-quiet wireless power supply system. Currently, the commonly used frequency tracking methods generally require comparing the phase difference between the primary coil voltage and current or the phase difference between the primary coil voltage and the secondary coil voltage. Although automatic tuning can be achieved, they are both relatively complex. In order to ensure that the power supply system always works in a resonant state and reduce circuit complexity, an analog-controlled self-resonant, ultra-quiet wireless power supply system is designed.

Contents of the invention

In order to overcome the shortcomings of the existing technology, the present invention aims to propose an analog-controlled self-resonant, ultra-quiet wireless power supply system. This system detects the voltage zero point of the transmitting coil and adjusts the switching frequency of the switching power supply to achieve automatic tracking of the resonant frequency, improve power supply power and efficiency, and reduce external electromagnetic interference. To this end, the technical solution adopted by the present invention is an analog-controlled self-resonant, ultra-quiet wireless power supply system, which consists of a power supply, a choke coil, a capacitor, a transmitting coil, a magnetic core, a receiving coil, a full-wave rectifier bridge, a voltage stabilizing capacitor, It consists of a resonant capacitor, a coupler, a zero-point detection control chip and a switch. The power supply is connected to the first pin of the choke coil, the second pin of the choke coil is connected to the first pin of the capacitor, and the second pin of the capacitor is connected. The second pin of the choke coil is connected to the center tap of the transmitting coil. The transmitting coil is coupled to the receiving coil through the magnetic core. The receiving coil is connected to a full-wave rectifier bridge composed of diodes of the same type. The rectifier bridge The output is connected to the voltage stabilizing capacitor to provide power to the load. The transmitting coil is connected in parallel with the resonant capacitor to form a resonant cavity. The center tap of the transmitting coil is connected to the zero-point detection control chip through a coupler. The zero-point detection control chip is connected to the gates of the two switches. Connected, the sources of the two switches are connected to ground respectively, and the drains of the two switches are connected to both ends of the transmitting coil.

The function of the power supply is to provide electric energy to the system; the choke and capacitor are used to ensure that the current through the circuit is continuous in all states; the magnetic core is used to improve the coupling coefficient between the transmitting coil and the receiving coil, and is also used to shield the transmitting coil and the The magnetic field lines of the receiving coil reduce the external electromagnetic interference between the transmitting coil and the receiving coil; the function of the voltage stabilizing capacitor is to make the voltage on the load a constant value; the function of the zero-point detection control chip is to detect the zero point of the voltage at the center tap of the transmitting coil, generating two The pulse width modulation PWM signal with opposite phase controls the two switches to be turned on alternately; the function of the two switches is to control the two ends of the transmitting coil to be alternately grounded.

The choke coil is used to ensure that the current through the circuit is continuous in all states; the coupling coefficient of the transmitting coil and the receiving coil is improved by using a magnetic core, and the magnetic lines of the transmitting coil and the receiving coil are shielded to reduce the external electromagnetic interference of the transmitting coil and the receiving coil. Interference; the zero-point detection control chip can send out a fixed-frequency PWM signal when the zero-point signal is not detected, and when the zero-point signal is detected, it can send out a PWM signal with a frequency half of the zero-point signal frequency.

When the system starts to work, the zero-point detection control chip first sends out two PWM control signals with opposite phases and a frequency slightly lower than the system resonant frequency, so that the two switches work in different states. At this time, the voltage at the center tap of the transmitting coil will appear as a sine wave. A waveform in the form of absolute value, and the frequency is twice the resonant frequency of the system. At the same time, the zero point detection control chip detects the center tap voltage of the transmitting coil. When the zero point detection control chip detects the zero point of the center tap voltage of the transmitting coil, the frequency of the PWM signal sent by the zero point detection control chip is consistent with the resonant frequency of the system. When the resonant frequency of the system fluctuates, the zero-point detection control chip can track the system frequency based on the zero point of the center tap voltage of the transmitting coil.

The switch works in a zero-voltage switching state. The power supply can be a linear power supply or a switching power supply. The capacitor can be a ceramic capacitor, a mica capacitor or a polystyrene capacitor. The transmitting coil can be made of enameled wire or Litz wire. The wire diameter, size and The number of turns is made according to the maximum transmission power; the magnetic core can be made of iron powder core, iron-aluminum-silicon powder core or ferrite core. The receiving coil can be made of enameled wire or Litz wire. The wire diameter, size and turns of the transmitting coil The numbers are made according to the maximum transmission power and meet the following conditions: the wire diameter of the transmitting coil is r _t , the coil radius is R _t , and the number of coil turns is N _t ; the wire diameter of the transmitting coil 6 is r _r , the coil radius is R _r , The number of turns of the coil is N _r . Then r _t =r _r , R _t =R _r , N _t =2N _r should be satisfied.

The full-wave rectifier bridge is composed of four rectifier diodes of the same type. The voltage stabilizing capacitor can be ceramic capacitor, mica capacitor or polystyrene capacitor; the resonant capacitor can be ceramic capacitor, mica capacitor or polystyrene capacitor, and the coupler can be direct coupling. mode or capacitive-resistance coupling mode. When the zero-point detection control chip does not detect the zero-point signal, it sends a constant-frequency PWM signal to control the switch. When the zero-point detection control chip detects the zero-point signal, the frequency of the PWM signal sent is twice the frequency of the zero-point signal. times; the switch can use a triode or a power field effect transistor, and the switch 12 should have a sufficiently high withstand voltage value and conduction current.

The characteristics and beneficial effects of the present invention are:

1) The analog-controlled self-resonant and ultra-quiet wireless power supply system based on the zero-crossing comparison method uses magnetic lines of force generated by magnetic core convergence coils, which can effectively reduce the system's external electromagnetic interference.

2) The analog-controlled self-resonant and ultra-quiet wireless power supply system based on the zero-crossing comparison method can automatically track the resonant frequency of the power supply system so that the system always works in a resonant state.

3) The analog-controlled self-resonant and ultra-quiet wireless power supply system based on the zero-crossing comparison method always works at the resonant frequency, which can improve the power and efficiency of wireless power supply.

Picture description:

Figure 1 An analog-controlled self-resonant, ultra-quiet wireless power supply system.

In Figure 1, 1 is the power supply, 2 is the choke, 3 is the capacitor, 4 is the transmitting coil, 5 is the magnetic core, 6 is the receiving coil, 7 is the full-wave rectifier bridge, 8 is the voltage stabilizing capacitor, and 9 is the resonant capacitor. , 10 is the coupler, 11 is the zero point detection control chip, 12 is the switch

Detailed ways

In order to achieve the purpose of the present invention, an analog-controlled self-resonant, ultra-quiet wireless power supply system is proposed, including: power supply 1, choke coil 2, capacitor 3, transmitting coil 4, magnetic core 5, receiving coil 6, and full-wave rectifier bridge 7. Voltage stabilizing capacitor 8, resonant capacitor 9, coupler 10, zero point detection control chip 11, switch 12.

An analog-controlled self-resonant, ultra-quiet wireless power supply system, as shown in Figure 1. Power supply 1 is connected to the first pin of choke coil 2, and the second pin of choke coil 2 is connected to the first pin of capacitor 3. pins connected, the second pin of capacitor 3 is connected to ground.

Further, the second pin of the choke coil 2 is connected to the center tap of the transmitting coil 4. The transmitting coil 4 is coupled with the receiving coil 6 through the magnetic core 5. The receiving coil 6 is composed of four diodes of the same type for full-wave rectification. Bridge 7 connection.

Further, the output of the rectifier bridge 7 is connected to the voltage stabilizing capacitor 8 to provide power to the load.

Further, the transmitting coil 4 and the resonant capacitor 9 are connected in parallel to form a resonant cavity.

Further, the center tap of the transmitting coil 4 is connected to the zero-point detection control chip 11 through the coupler 10 , and the zero-point detection control chip 11 is connected to the gates of the two switches 12 .

Further, the sources of the two switches 12 are respectively connected to the ground, and the drains of the two switches 12 are connected to both ends of the transmitting coil 4 respectively.

Further, the function of power supply 1 is to provide electric energy to the system; the function of choke coil 2 and capacitor 3 is to ensure that the current through the circuit is continuous in all states; one function of magnetic core 5 is to improve the connection between transmitting coil 4 and receiving coil 6 The coupling coefficient, another function of the magnetic core 5 is to shield the magnetic lines of force between the transmitting coil 4 and the receiving coil 6, and reduce the external electromagnetic interference of the transmitting coil 4 and the receiving coil 6; the function of the voltage stabilizing capacitor 8 is to keep the voltage on the load constant value; the function of the zero-point detection control chip 11 is to detect the zero point of the voltage at the center tap of the transmitting coil 4, and generate two PWM signals with opposite phases to control the two switches 12 to conduct alternately; the function of the two switches 12 is to control the voltage of the transmitting coil 4 Alternately connect both ends to ground.

Further, in the present invention, the choke coil 2 is used to ensure that the current through the circuit is continuous in all states; the magnetic core 5 is used to improve the coupling coefficient of the transmitting coil 4 and the receiving coil 6, and at the same time shield the transmitting coil 4 and the receiving coil. The magnetic field lines of the coil 6 reduce the external electromagnetic interference of the transmitting coil 4 and the receiving coil 6; when the zero point signal is not detected, the zero point detection control chip 11 can send out a PWM signal of a fixed frequency, and when the zero point signal is detected, it can send out a PWM signal with a frequency of PWM signal with half the frequency of the zero signal.

Furthermore, when the system starts to work, the zero-point detection control chip 11 first sends out two PWM control signals with opposite phases and a frequency slightly lower than the system resonant frequency, so that the two switches 13 work in different states. At this time, the center tap of the transmitting coil 4 The voltage at the voltage will appear in the form of a sine wave absolute value, and the frequency is twice the resonant frequency of the system. At the same time, the zero point detection control chip 11 detects the center tap voltage of the transmitting coil 4 . When the zero point detection control chip 11 detects the zero point of the center tap voltage of the transmitting coil 4, the frequency of the PWM signal sent by the zero point detection control chip 11 is consistent with the resonant frequency of the system. When the resonant frequency of the system fluctuates, the zero point detection control chip 11 can track the system frequency based on the zero point of the center tap voltage of the transmitting coil 4 .

Furthermore, the switch 13 operates in a zero-voltage switching state, which can effectively reduce switching losses and improve system efficiency.

Further, the power supply 1 can adopt common power supplies such as linear power supply and switching power supply. For example, use the switching power supply model LRS-50-24 of MEAN WELL Electronics Co., Ltd.

Furthermore, the choke coil 2 can be a commonly used choke coil or an inductor with a large inductance. For example, a honeycomb inductor with an inductance of 220uH is used.

Further, the capacitor 3 can be a ceramic capacitor, a mica capacitor, a polystyrene capacitor, etc. For example, use a ceramic capacitor with a capacitance of 0.047uF.

Furthermore, the transmitting coil 4 can be made of enameled wire, Litz wire, etc. The wire diameter, size and number of turns of the transmitting coil 4 are made according to the maximum transmission power. For example, an enameled wire with a wire diameter of 0.8mm is used to make a coil with an inner diameter of 15mm, an outer diameter of 35mm, and a number of turns of 36.

Furthermore, the magnetic core 5 may be an iron powder magnetic core, an iron-aluminum-silicon powder magnetic core, a ferrite magnetic core, or the like. For example, use the ferrite core model GU36.

Furthermore, the receiving coil 6 can be made of enameled wire, Litz wire, etc. The wire diameter, size and number of turns of the transmitting coil 6 are made according to the maximum transmission power. At the same time, the following conditions are met: Assume that the wire diameter of the transmitting coil 4 is r _t , the coil radius is R _t , and the number of coil turns is N _t ; the wire diameter of the transmitting coil 6 is r _r , the coil radius is R _r , and the coil number of turns is N _r . Then r _t =r _r , R _t =R _r , N _t =2N _r should be satisfied. For example, an enameled wire with a wire diameter of 0.8mm is used to make a coil with an inner diameter of 15mm, an outer diameter of 35mm, and a number of turns of 18.

Further, the full-wave rectifier bridge 7 can be composed of four rectifier diodes of the same type. For example, use the rectifier diode model 1N5819.

Further, the voltage stabilizing capacitor 8 may be a ceramic capacitor, a mica capacitor, a polystyrene capacitor, etc. For example, use a ceramic capacitor with a capacitance of 1uF.

Furthermore, the resonant capacitor 9 can be a ceramic capacitor, a mica capacitor, a polystyrene capacitor, etc. For example, use a ceramic capacitor with a capacitance of 10uF.

Furthermore, the coupler 10 may adopt a direct coupling method, a capacitive-resistance coupling method, etc. For example, use a resistor with a resistance of 100kΩ.

Furthermore, the zero-point detection control chip 11 may be a common resonant lamp ballast control chip. When the zero-point detection control chip 11 does not detect the zero-point signal, it sends a PWM signal with a constant frequency to control the switch 12. When the zero-point detection control chip 11 detects the zero-point signal, the frequency of the PWM signal it sends is twice the frequency of the zero-point signal. For example, the resonant lamp ballast control chip model UC1872 is used.

Further, the switch 12 may be a triode, a power field effect transistor, or the like. The switch 12 should have a sufficiently high withstand voltage value and conduction current. For example, use the power field effect transistor model INR540N.

Claims (4)

1. The analog control self-resonance and ultra-silence wireless power supply system is characterized by comprising a power supply, a choke coil, a capacitor, a transmitting coil, a magnetic core, a receiving coil, a full-wave rectifier bridge, a voltage stabilizing capacitor, a resonant capacitor, a coupler, a zero detection control chip and a switch, wherein the power supply is connected with a first pin of the choke coil, a second pin of the choke coil is connected with a first pin of the capacitor, and a second pin of the capacitor is grounded; the second pin of the choke coil is connected with the center tap of the transmitting coil, the transmitting coil is coupled with the receiving coil through a magnetic core, the receiving coil is connected with a full-wave rectifier bridge formed by 4 diodes with the same model, the output of the rectifier bridge is connected with a voltage stabilizing capacitor to provide power for a load, the transmitting coil is connected with a resonant capacitor in parallel to form a resonant cavity, the center tap of the transmitting coil is connected with a zero detection control chip through a coupler, the zero detection control chip is connected with grid electrodes of two switches, source electrodes of the two switches are respectively grounded, and drain electrodes of the two switches are respectively connected with two ends of the transmitting coil;

when the system starts to work, the zero point detection control chip firstly sends out two paths of PWM control signals which are opposite in phase and slightly lower in frequency than the system resonant frequency, so that the two switches work in different states, at the moment, the voltage at the center tap of the transmitting coil can generate a waveform in the form of sine wave absolute value, and the frequency is 2 times of the system resonant frequency; meanwhile, the zero detection control chip detects the center tap voltage of the transmitting coil; when the zero detection control chip detects the zero of the center tap voltage of the transmitting coil, the frequency of the PWM signal sent by the zero detection control chip is consistent with the resonance frequency of the system; when the resonance frequency of the system fluctuates, the zero detection control chip can track the frequency of the system according to the zero point of the center tap voltage of the transmitting coil;

the power supply is used for providing electric energy for the system; the choke and the capacitor are used to ensure that the current through the circuit is continuous in all states; the magnetic core is used for improving the coupling coefficient of the transmitting coil and the receiving coil, shielding magnetic force lines of the transmitting coil and the receiving coil and reducing electromagnetic interference outside the transmitting coil and the receiving coil; the voltage stabilizing capacitor is used for enabling the voltage on the load to be a constant value; the zero detection control chip is used for detecting the zero of the voltage at the center tap of the transmitting coil and generating two paths of Pulse Width Modulation (PWM) signals with opposite phases to control the two switches to be alternately conducted; the two switches are used for controlling the two ends of the transmitting coil to be alternately grounded.

2. The analog controlled self-resonating, ultra-silent wireless power supply system of claim 1, wherein the current through the circuit is ensured to be continuous in all states by using chokes; the magnetic core is adopted to improve the coupling coefficient of the transmitting coil and the receiving coil, and simultaneously shield magnetic force lines of the transmitting coil and the receiving coil, so that electromagnetic interference outside the transmitting coil and the receiving coil is reduced; the zero point detection control chip can send out PWM signals with fixed frequency when no zero point signal is detected, and can send out PWM signals with frequency which is half of the frequency of the zero point signal when the zero point signal is detected.

3. The analog controlled self-resonant, ultra-silent wireless power supply system according to claim 1, wherein the switch operates in a zero-voltage switching state, the power supply can be a linear power supply or a switching power supply, the capacitor can be a ceramic capacitor, a mica capacitor or a polystyrene capacitor, the transmitting coil can be made of enameled wire or litz wire, and the wire diameter, the size and the turns of the transmitting coil are made according to the maximum transmission power; the magnetic core can be an iron powder magnetic core, an iron aluminum silicon powder magnetic core or a ferrite magnetic core, the receiving coil can be manufactured by enamelled wires or litz wires, the wire diameter, the size and the number of turns of the transmitting coil are manufactured according to the maximum transmission power, and the following conditions are met simultaneously: the wire diameter of the transmitting coil is r _t The radius of the coil is R _t The number of turns of the coil is N _t The method comprises the steps of carrying out a first treatment on the surface of the The wire diameter of the receiving coil is r _r The radius of the coil is R _r The number of turns of the coil is N _r Then r should be satisfied _t ＝r _r ,R _t ＝R _r ,N _t ＝2N _r 。

4. The analog controlled self-resonance and ultra-silent wireless power supply system according to claim 1, wherein the full-wave rectifier bridge is composed of 4 types of rectifier diodes, and the voltage stabilizing capacitor can be a ceramic capacitor, a mica capacitor or a polystyrene capacitor; the resonance capacitor can adopt a ceramic capacitor, a mica capacitor or a polystyrene capacitor, the coupler can adopt a direct coupling mode or a capacitance-resistance coupling mode, when the zero point detection control chip does not detect a zero point signal, a constant-frequency PWM signal control switch is sent out, and when the zero point detection control chip detects the zero point signal, the frequency of the sent PWM signal is twice the frequency of the zero point signal;

the switch may be a triode or a power field effect transistor, and the switch should have a sufficiently high withstand voltage and on-current.