CN115580961A - Multi-channel wireless power transmission LED drive circuit based on constant current source compensation network - Google Patents

Abstract

The invention relates toThe technical field of LED wireless driving, in particular to a multipath wireless power transmission LED driving circuit based on a constant current source compensation network. The receiving end comprises multiple paths of constant current output units, each path of constant current output unit is connected through a non-contact transformer, and the input end of the first constant current output unit is connected through a non-contact transformer T _m The constant current output unit comprises an AC/DC rectification unit and an LED load string, the output end of the power supply is connected with the input end of the DC/AC inversion unit, the output end of the DC/AC inversion unit is connected with the input end of the passive resonance constant current unit, and the output end of the passive resonance constant current unit is connected with the contactless transformer T _m Primary side connected, contactless transformer T _m The secondary side of the first constant current output unit is connected with an AC/DC rectifying unit of the first constant current output unit, and the output end of the AC/DC rectifying unit is connected with the LED load string. The circuit has the advantages of simple structure, high efficiency and low cost.

Description

Multi-channel wireless power transmission LED drive circuit based on constant current source compensation network

technical field

The invention relates to the technical field of LED wireless driving, in particular to a multi-channel wireless power transmission LED driving circuit based on a constant current source compensation network.

Background technique

Compared with traditional lighting methods, LED (light emitting diode) lighting has outstanding advantages such as high efficiency, energy saving, no pollution, and long life. It is regarded as the "fourth generation lighting source". Street lighting, tunnel lighting, landscape lighting and other lighting fields have been widely used. According to the voltage and current variation characteristics of LED devices, there are usually two driving methods: one is to use constant voltage source + multiple constant current sources to drive. This method is to provide power for multiple constant current sources at the same time by one constant voltage source. Each constant current source drives a group of lamps. This method has flexible circuit combinations, and the failure of a single lamp group will not affect the normal operation of other lamps. However, the control is more complicated and the cost is higher. Second, it is driven by a direct constant current source, the control method is simple and the cost is low.

As an emerging power transmission technology, wireless power transmission technology has the advantages of safety, reliability, flexibility and convenience, so it is widely used in electronic equipment, electric vehicles and human medical implant equipment and other fields. The use of wireless power transmission technology is widely used in the occasions of constant current or constant voltage power supply of electrical equipment, and adding a reasonable compensation network to the wireless power transmission system can not only eliminate reactive power circulation to improve power factor, but also realize load-independent Constant current or constant voltage output. Therefore, designing a reasonable compensation network to achieve constant current or constant voltage output is one of the hotspots in the research of wireless power transfer technology. The focus of the research of the present invention is to use the constant current source type compensation network to realize multi-channel wireless drive output under a simpler control method through the wireless energy transmission technology.

In order to realize multi-channel constant current output, relevant literatures have been researched on constant current output resonant compensation network and topological structure. Some scholars have proposed a topology in which a single inverter is connected in parallel with multiple IPT systems. In the paper "Research on Compensation Topology for Constant Output of Inductive Wireless Power Transfer System", a transformer is connected to a series of loads, and multiple transformers are used to realize multi-channel constant output. Current output, in which each secondary side of the transformer requires a resonant compensation network, so the circuit structure is complex and the cost is high. In order to simplify the structure and save cost, in the "Research on LED Drive Circuit without Electrolytic Capacitor Based on LCL Constant Current Resonant Network" published by the Journal of Power Supply, a boost-PFC converter in the front stage and a half-bridge LCL resonant converter in the rear stage are proposed. The LED driving power supply is composed, and a constant alternating current is generated by using an LCL resonant circuit on the primary side of the transformer. This topology can greatly simplify the circuit, but it cannot realize multiple constant current outputs of LEDs.

Contents of the invention

The purpose of the present invention is to provide a multi-channel wireless power transmission LED drive circuit based on a constant current source compensation network, which has a simple circuit structure, high efficiency and low cost.

A multi-channel wireless power transmission LED drive circuit based on a constant current source compensation network provided by the present invention includes a transmitting end and a receiving end, and the receiving end includes multiple constant current output units, each of the constant current output units The input terminal of the first constant current output unit is also connected to the transmitting terminal through a contactless transformer T _m , and the transmitting terminal includes a DC/AC inverter unit and a passive resonant constant current unit, the constant current output unit includes an AC/DC rectifier unit and an LED load string, the output end of the power supply is connected to the input end of the DC/AC inverter unit, and the output end of the DC/AC inverter unit is connected to the The input end of the passive resonant constant current unit is connected, the output end of the passive resonant constant current unit is connected to the primary side of the non-contact transformer T _m , and the secondary side of the non-contact transformer T _m is connected to the first said constant current unit. The AC/DC rectifier unit of the current output unit is connected, and the output terminal of the AC/DC rectifier unit is connected in series with the LED load, wherein each of the constant current output units includes a plurality of AC/DC rectifiers connected in series unit and a plurality of LED load strings corresponding to each AC/DC rectification unit.

More preferably, the DC/AC inverter unit is a full-bridge inverter network, and the full-bridge inverter network includes switch tubes S ₁ -S ₄ , and the sources of switch tubes S ₁ and S ₃ are respectively connected to switch tube S _{2. The} drain of S4.

More preferably, the passive resonant constant current unit is an LCL-T network, the passive resonant constant current unit includes an inductor L _am , an inductor L _bm and a capacitor C _m , and one end of the inductor L _bm is connected to a non-contact The terminal with the same name on the primary side of the transformer T _m , the other end is connected to one end of the capacitor C _m and the inductor L _am at the same time, the other end of the capacitor C _m is connected to the non-identical end of the primary side of the transformer, and the other end of the inductor L _am is connected to the DC/AC inverter output of the unit.

More preferably, the AC/DC rectification unit includes diodes D _ij ~ D _{(i+3) j} and capacitor C _oji , the anode of the diode D _ij , the cathode of the diode D _{(i+1) j} and the non-contact transformer The secondary side of T _j is connected, the diode D _ij is connected to the cathode of D _{(i+2) j} , and is connected to one end of the capacitor C _oji , one end of the capacitor C _oji is connected to the positive end of the LED load string, and the diode D _(i The anodes of _+1)j and D _(i+3)j are connected to the other end of the capacitor C _oji , and the other end of the capacitor C _oji is connected to the negative end of the LED load string;

Among them, the constant current output unit at the receiving end is s-m+1, and the number of AC/DC rectifier units set in each constant current output unit is n, i takes any natural number from 1 to n, and j takes m~s any natural number in .

More preferably, it also includes an open-loop control circuit, the open-loop control circuit includes a first pulse width modulator, a phase shift modulation unit and a first driver, the PWM control signal output terminal of the first pulse width modulator is connected to the shift The input end of the phase modulation unit is connected, the output end of the phase shift modulation unit is connected to the input end of the first driver, and the output end of the first driver is connected to the control signal input end of the DC/AC inverter unit.

More preferably, it also includes a closed-loop control circuit, the closed-loop control circuit includes an adder, a compensator, a second pulse width modulator and a second driver, and the sampling current output terminal and the reference current input terminal of the LED load string are connected to The input end of the adder is connected, the output end of the adder is connected with the input end of the compensator, the output end of the compensator is connected with the input end of the second pulse width modulator, and the output end of the second pulse width modulator The PWM control signal output terminal is connected to the input terminal of the second driver, and the output terminal of the second driver is connected to the control signal input terminal of the DC/AC inverter unit.

More preferably, the inductance value of the inductance L _am in the passive resonant constant current unit is greater than the inductance value of the inductance L _bm .

More preferably, when the first pulse width modulator outputs a specified duty cycle K, the phase shift angle is adjusted within the range of 0 to 180° by the phase shift modulation unit, so that the output current of the LED load string is maintained at a specified accuracy Inside.

More preferably, the control method of the closed-loop control circuit includes:

The adder calculates the current error I err between the LED load string sampling current I LED and the reference current I ref, I LED- I ref= I err;

When Ierr >0, the compensator output value X increases, and the second pulse width modulator adjusts the PWM control signal duty cycle to increase;

When I err<0, the output value X of the compensator decreases, and the second pulse width modulator adjusts the duty cycle of the PWM control signal to decrease.

The beneficial effects of the present invention are:

1. The multi-channel isolated output of this circuit only uses the resonant network on the primary side of the transformer, which reduces the use of the secondary side resonant network, and only needs to add a rectifier unit for each additional output, which is easy to realize modular multi-channel constant current output, and its efficiency Higher and less expensive. At the same time, this circuit uses multi-stage series connection of transmission line transformers to realize multi-channel LED constant current output. By connecting multiple rectifier units in series, open-loop control can be used in most applications, and the overall control scheme is simple and easy to implement.

2. This program sets an open-loop control circuit, and the open-loop control circuit includes a first pulse width modulator, a phase-shift modulation unit and a first driver, and the duty ratio of the PWM control signal output by the first pulse width modulator is directly given , combined with the phase-shift modulation unit to adjust the phase-shift angle within the range of 0~180°, the output current of the LED load string can be kept within any specified accuracy, thereby realizing constant current output.

3. In this solution, a closed-loop control circuit is provided, and the closed-loop control circuit includes an adder, a compensator, a second pulse width modulator, and a second driver. The adder calculates the current error I err between the sampling current I LED of the LED load string and the reference current I ref. When I err>0, the output value X of the compensator increases, and the second pulse width modulator adjusts the duty ratio of the PWM control signal to increase Large; when I err<0, the compensator output value X decreases, and the second pulse width modulator adjusts the PWM control signal duty cycle to decrease. So that I LED = I ref, to achieve constant current output in harsh environments.

4. In this scheme, the inductance L _am in the passive resonant constant current unit is designed to be greater than the inductance L _bm , so that the switching tubes in the DC/AC inverter unit can realize soft switching, thereby reducing switching loss and improving efficiency .

Description of drawings

1 is a schematic diagram of the architecture of a multi-channel wireless power transmission LED drive circuit based on a constant current source compensation network in the present invention;

2 is a schematic diagram of a wireless LED drive system in a multi-channel wireless power transmission LED drive circuit based on a constant current source compensation network according to the present invention;

FIG. 3 is a schematic structural diagram of a full-bridge inverter network constituting a DC/AC inverter unit;

4 is a schematic diagram of the LCL-T resonant network constituting the passive resonant constant current network in the AC/DC passive resonant constant current unit;

5 is a schematic diagram of a bridge rectifier circuit constituting a rectifier module in an AC/DC passive resonant constant current unit;

6 is a circuit diagram of a preferred embodiment of a multi-channel wireless power transmission LED drive circuit based on a constant current source compensation network according to the present invention;

Fig. 7 is a kind of switching tube driving and main working waveform schematic diagram of the circuit shown in Fig. 6;

Fig. 8 is when the circuit shown in Fig. 6 works under the open loop, the emulation waveform diagram of the voltage and current at the rated operating point at the _two ends _of the switching tubes S1 and S2;

Figures 9 to 12 are simulation waveform diagrams of the output currents of the main circuit and the secondary circuit under different output loads when the circuit shown in Figure 6 works in an open loop;

Figures 13 to 15 are simulation waveform diagrams of the output current changing with the output load for different input voltages when the circuit shown in Figure 6 works in an open loop;

Figures 16 to 17 are simulation waveform diagrams of the output voltage and current when the circuit shown in Figure 6 works in an open loop and the load changes suddenly;

Figures 18 to 20 are simulation waveform diagrams of the output voltage and current under different phase shift angles when the circuit shown in Figure 6 works in an open loop;

Figures 21 to 23 are the simulated waveform diagrams of the output voltage and current after the output voltage and current are stable when the circuit shown in Figure 6 is working in a closed loop with different input voltages, that is, when the input voltage changes greatly;

Figures 24 to 25 are simulation waveform diagrams of the output voltage and current when the circuit shown in Figure 6 works in a closed loop and the input voltage changes suddenly;

Fig. 26 is a schematic diagram of the waveform among the resonance current, the switching tube current and the switching tube voltage;

Figures 27 and 28 are vector diagrams made according to the relationship between the parameters of the resonant network.

detailed description

In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.

It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and/or components, but does not exclude one or more other Presence or addition of features, wholes, steps, operations, elements, components and/or collections thereof.

It should also be understood that the term "and/or" used in the description of the present application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

As used in this specification and the appended claims, the term "if" may be construed, depending on the context, as "when" or "once" or "in response to determining" or "in response to detecting ". Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be construed, depending on the context, to mean "once determined" or "in response to the determination" or "once detected [the described condition or event] ]” or “in response to detection of [described condition or event]”.

In addition, in the description of the specification and appended claims of the present application, the terms "first", "second", "third" and so on are only used to distinguish descriptions, and should not be understood as indicating or implying relative importance.

Reference to "one embodiment" or "some embodiments" or the like in the specification of the present application means that a particular feature, structure, or characteristic described in connection with the embodiment is included in one or more embodiments of the present application. Thus, appearances of the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in other embodiments," etc. in various places in this specification are not necessarily All refer to the same embodiment, but mean "one or more but not all embodiments" unless specifically stated otherwise. The terms "including", "comprising", "having" and variations thereof mean "including but not limited to", unless specifically stated otherwise. "Multiple" means "two or more".

Embodiment one

Figure 1 shows a schematic diagram of the structure of a multi-channel wireless power transmission LED drive circuit based on a constant current source compensation network provided by a preferred embodiment of the application (Figure 1 shows the first embodiment of the application), for the convenience of description , only shows the part relevant to this embodiment, detailed description is as follows:

A multi-channel wireless power transmission LED drive circuit based on a constant current source compensation network provided by the present invention includes a transmitting end and a receiving end, and the receiving end includes multiple constant current output units, each of the constant current output units The input terminal of the first constant current output unit is also connected to the transmitting terminal through a contactless transformer T _m , and the transmitting terminal includes a DC/AC inverter unit and a passive resonant constant current unit, the constant current output unit includes an AC/DC rectifier unit and an LED load string, the output end of the power supply is connected to the input end of the DC/AC inverter unit, and the output end of the DC/AC inverter unit is connected to the The input end of the passive resonant constant current unit is connected, the output end of the passive resonant constant current unit is connected to the primary side of the non-contact transformer T _m , and the secondary side of the non-contact transformer T _m is connected to the first said constant current unit. The AC/DC rectifier unit of the current output unit is connected, and the output terminal of the AC/DC rectifier unit is connected in series with the LED load, wherein each of the constant current output units includes a plurality of AC/DC rectifiers connected in series unit and a plurality of LED load strings corresponding to each AC/DC rectification unit. Based on the idea and method of the present invention, different multi-channel constant current LED driving power sources can be obtained through reasonable combination of topological structures in each conversion unit.

As shown in Figure 2, the DC power supply in the present invention generates a high-frequency drive source through the DC/AC inverter unit and the passive resonant network, and the electric energy is transmitted to the receiving network through the transmitting end of the transmission network, and supplied to the LED load, thereby realizing multi-channel LED constant current output.

The DC/AC inverter unit can adopt full-bridge and half-bridge inverter network structures. As shown in Figure 3, it is a full-bridge inverter network. The input of the full-bridge inverter network is connected to the DC voltage U _dc , and the full-bridge inverter network Including switching tubes S ₁ -S ₄ , the sources of switching tubes S ₁ and S ₃ are respectively connected to the drains of switching tubes S ₂ and S ₄ , and switching tubes S ₁ -S ₄ are N-channel MOSFETs.

The passive resonant constant current network that can constitute the AC/DC passive resonant constant current unit can be of four topological structures: LCL-T, CLC-π, CLC-T or LCL-π resonant network. As shown in Figure 4, the passive resonant constant current unit in the AC/DC passive resonant constant current unit adopts an LCL-T network, and the passive resonant constant current unit includes an inductor L _am , an inductor L _bm and a capacitor C _m , one end of the inductance L _bm is connected to the same-named end of the primary side of the non-contact transformer T _m , the other end is connected to one end of the capacitor C _m and the inductance L _am at the same time, and the other end of the capacitor C _m is connected to the non-identical end of the primary side of the transformer , the other end of the inductor L _am is connected to the output end of the DC/AC inverter unit.

The three topologies that can constitute the rectification module in the AC/DC rectification unit can be half-wave rectification, bridge rectification, and double voltage rectification circuits. Figure 5 shows a bridge rectifier circuit, which includes diodes D _ij ~ D _{(i+3) j} and capacitor C _oji , the anode of the diode D _ij , the cathode of the diode D _{(i+1) j} and The secondary side of the non-contact transformer T _j is connected, the diode D _ij is connected to the cathode of D _{(i+2) j} , and is connected to one end of the capacitor C _oji , one end of the capacitor C _oji is connected to the positive end of the LED load string, and the diode The anodes of D _(i+1)j and D _(i+3)j are connected to the other end of the capacitor C _oji , and the other end of the capacitor C _oji is connected to the negative end of the LED load string;

Among them, the constant current output unit at the receiving end is s-m+1, and the number of AC/DC rectifier units set in each constant current output unit is n, i takes any natural number from 1 to n, and j takes m~s any natural number in .

As shown in Fig. 6, it is a kind of preferred circuit topological diagram of the circuit of the present invention, and its each component adopts the full-bridge inverter network shown in Fig. 3~5 respectively, LCL-T type network and bridge rectification structure, And it also includes an open-loop control circuit and a closed-loop control circuit.

The open-loop control circuit includes a first pulse width modulator, a phase shift modulation unit and a first driver, the PWM control signal output end of the first pulse width modulator is connected to the input end of the phase shift modulation unit, and the phase shift modulation The output terminal of the unit is connected with the input terminal of the first driver, and the output terminal of the first driver is connected with the control signal input terminal of the DC/AC inverter unit.

The closed-loop control circuit includes an adder, a compensator, a second pulse width modulator, and a second driver, and the sampling current output terminal and the reference current input end of the LED load string are connected to the input end of the adder, and the adder's The output terminal is connected to the input terminal of the compensator, the output terminal of the compensator is connected to the input terminal of the second pulse width modulator, and the PWM control signal output terminal of the second pulse width modulator is connected to the input terminal of the second driver connected, the output end of the second driver is connected to the control signal input end of the DC/AC inverter unit.

The contactless transformer T is used between the LCL-T resonant network and the bridge rectifier network to realize input and output isolation, and to complete the wireless transmission of electric energy. Voltage, so that in the change of switch state, the voltage drops to zero before turning on, and the current drops to zero before turning off, so as to realize soft switching. There are two wireless receivers in Figure 6. For the convenience of analysis, the parameters of the components of the two receivers can be set to be the same. The control adopts open-loop control or closed-loop control. In the open-loop control, the duty ratio K is directly given, and the switch tube is driven by the driver. The closed-loop control samples the output current of a certain channel, and obtains the error signal through the difference between the adder and the reference current. And the current error is sent to the compensator, and finally the switching tube is driven by the pulse width modulator and the driver.

As shown in FIG. 7 , Q ₁ -Q ₄ in the figure are driving waveforms of switching tubes S ₁ -S ₄ respectively, and the conduction time of S ₁ in one switching period T _SW is DT _SW . It is known from the driving waveform that S ₁ and S ₂ , and S ₃ and S ₄ are respectively conduction complementary. The driving phase of S ₃ relative to S ₁ is shifted by 180°, and within one switching cycle T _SW , the conduction times of S ₁ and S ₃ , S ₂ and S ₄ are equal, that is, phase shift control is adopted. However, it should be noted that this control method is not the only one, and any control method that can make the voltage u _ac at the output terminal of the inverter unit an AC square wave is acceptable.

In one embodiment, the inductance L _am in the passive resonant constant current unit is greater than the inductance L _bm . The specific analysis process is as follows:

Through the reasonable parameter design of the passive resonant constant current network, the switching tubes in the DC/AC inverter unit can realize soft switching, thereby reducing the switching loss and improving the efficiency.

Taking the LCL-π resonant network as an example, only the fundamental component is considered, and the high-order harmonics are not considered, the input current I _Lam and the output current I _Lbm of the resonant network can be derived from the following formula:

；

;

；

;

Where I _Lam is the input side current, I _Lbm is the output side current, L _am is the input side inductance, L _bm is the output side inductance, U _am is the input side voltage, U _bm is the output side voltage, ω _SW is the switching angular frequency.

In order to reduce the loss of the switching tube and improve the efficiency of the power supply, there are two soft switching methods of zero voltage switching (ZVS) and zero current switching (ZCS). Zero-voltage switching (ZVS) means that the voltage of the switch tube drops to zero before it is turned on, and remains at zero when it is turned off. Zero-current switching (ZCS) even if the current of the switch tube is kept at zero when it is turned on, the current drops to zero before it is turned off. As shown in Figure 26, to realize zero-voltage switching (ZVS), the voltage of the switch tube should lead the current, that is, before the switch tube is turned on, the current flows through the body diode (S to D) of the switch MOS tube, and the switch MOS tube The voltage between the tube D-S is clamped close to 0V (diode voltage drop). At this time, the switch MOS tube is turned on to achieve zero-voltage conduction; before it is turned off, because the capacitor voltage between D-S is 0V and cannot be mutated, Therefore, it is also close to zero voltage turn-off.

According to the relationship between the parameters of the resonant network, considering the situation that L _am is greater than L _bm and L _am is less than L _bm , the following vector diagrams are made, as shown in Figures 27 and 28. It can be seen from the figure that only when L _am is greater than L _bm , can the switch be satisfied. The condition that the tube voltage is ahead of the current, so as to realize zero-voltage switching, when selecting parameters, it should be ensured that L _am is greater than L _bm to meet the design requirements.

In one embodiment, when the first pulse width modulator outputs a specified duty ratio K, the phase shift angle is adjusted within the range of 0° to 180° by the phase shift modulation unit, so that the output current of the LED load string is maintained at the specified within the accuracy.

The DC voltage is controlled by phase-shift modulation through the output voltage of the inverter. As a band-pass filter, the high-order resonant circuit mainly passes the fundamental wave component of the inverter output voltage. Therefore, in order to simplify the analysis, only the fundamental wave component is considered here, and the inverter output voltage U _am :

；

;

Among them, U _dc is the input DC voltage, and α is the phase shift angle.

Taking the LCL-π resonant network as an example, when only the fundamental component is considered and the high-order harmonics are not considered, the current I _{Lbm at} the output side of the resonant network can be derived by the following formula:

；

;

Where U _am is the input side voltage, that is, the output voltage of the inverter, and L _am is the input side inductance.

Substitution can be obtained:

；

;

From the above formula, it can be concluded that the phase shift angle is in the range of 0~180°, and the output side current I _Lbm increases with the increase of α . Therefore, in the open loop, the phase shift angle can be reasonably selected according to this method. size, in order to get a suitable constant current output. This modulation method is for reference only, and other modulation methods can be reasonably selected to achieve the required constant current output.

In one embodiment, the control method of the closed-loop control circuit includes:

The adder calculates the current error I err between the LED load string sampling current I LED and the reference current I ref, I LED- I ref= I err;

When Ierr >0, the compensator output value X increases, and the second pulse width modulator adjusts the PWM control signal duty cycle to increase;

When I err<0, the output value X of the compensator decreases, and the second pulse width modulator adjusts the duty cycle of the PWM control signal to decrease.

Embodiment two

In this embodiment, the open-loop control process of this solution will be described in conjunction with various simulation diagrams of the circuit shown in FIG. 6 under open-loop control.

The input and output of this embodiment and the parameters of each component are set as follows:

Rated input voltage U _dc =80V, rated output current 0.56A, rated output voltage 45V, switching frequency 100kHZ, transformer turns ratio N = n ₁ : n ₂ =2.3, inductance L _am =270μH, inductance L _bm =75μH, capacitance C _m =9.38nF, capacitance C _om =150µF.

Figure 8 shows the voltage and current waveforms of the switch tube at the rated operating point when the circuit shown in Figure 6 works in an open loop.

When the output load changes, its output current can be kept at the rated value of 0.56A basically unchanged. As shown in Figure 9, the output voltage of the main road and the slave road is about 44.5V, and the output current I _os1 of the slave road is about 0.556A; as shown in Figure 10, the output voltage U _om1 of the main road is about 44.7V, and the output voltage of the slave road U _os1 is about 22.4V, and the slave output current I _os1 is about 0.556A; as shown in Figure 11, the main output voltage U _om1 is about 11.24V, the slave output voltage U _os1 is about 44.97V, and the slave output current I _os1 is about 0.562A; as shown in Figure 12, the master output voltage U _om1 is about 11.5V, the slave output voltage U _os1 is about 17.2V, and the slave output current I _os1 is about 0.573A. It can be seen from the above that although changes in the output voltage of the main circuit and the slave circuit will affect the output current of the slave circuit, the accuracy of the slave circuit current can be kept within 5% (0.556A-0.573A), and the output has high current accuracy.

U _o1 and U _o2 represent output voltages of any two LED strings respectively, and I _o1 and I _o2 represent output currents of corresponding branches respectively. As shown in Figure 13, the waveform diagram when the input voltage is 78V, in the figure, when the output voltage U _o1 is about 43.1V, the corresponding output current is about 0.54A, and when the output voltage U _o2 is about 32.4V, the corresponding output current is about 0.54A ; As shown in Figure 14, the waveform diagram when the input voltage is 80V, the corresponding output current is about 0.55A when the output voltage U _o1 is about 44.3V in the figure, and the corresponding output current is about 0.55A when the output voltage U _o2 is about 33.2V A; As shown in Figure 15, the waveform diagram when the input voltage is 82V, in the figure, when the output voltage U _o1 is about 45.36V, the corresponding output current is about 0.567A, and when the output voltage U _o2 is about 34V, the corresponding output current is about 0.567 a. It can be seen from the above that in the open-loop working mode, when the input and output voltages change within a certain range, the output current accuracy can be kept within 5% (0.54A-0.567A), and the output has high current accuracy.

U _o1 and I _o1 represent the output voltage and current of the LED branch where the load mutation occurs, and U _o2 and I _o2 represent the output voltage and current of any other LED branch. As shown in Figure 16, the waveform diagram of the output voltage and current when the load suddenly drops, at this time, the branch voltage U _o1 of the sudden load drop gradually decreases from 45V to 24V, and the current I _o1 gradually stabilizes back to the initial value of 0.55A after a sudden increase, and the voltage and current are stable The time is 0.02s; the output voltage U _o2 gradually decreases from 44.6V to 44.15V, the output current Io2 gradually decreases from _0.557A to 0.552A, and the stabilization time is 0.03s; as shown in Figure 17, the output voltage and current waveform when the load suddenly increases As shown in the figure, the branch voltage U _o1 of the load mutation at this time gradually rises from 22.4V to 44.5V, and the current I _o1 gradually stabilizes back to the initial value of 0.56A after a sudden drop, and the voltage and current stabilization time is 0.02s; the output voltage U _o2 increases from 44.1 V gradually rises to 44.5V, the output current I _o2 gradually decreases from 0.551A to 0.556A, and the stabilization time is 0.05s; it can be seen from the above that in the open-loop mode, the output current accuracy can be maintained when the load changes suddenly. Within 5% (0.55A-0.556A), the output has high current accuracy and has a faster recovery speed.

U _o1 and U _o2 represent output voltages of any two LED strings respectively, and I _o1 and I _o2 represent output currents of corresponding branches respectively. As shown in Figure 18, the waveform diagram of the output voltage and current when the given phase shift angle is 60°, in the figure, when the output voltage U _o1 is about 21.94V, the corresponding output current is about 0.274A, and when the output voltage U _o2 is about 21.94V, the corresponding The output current is about 0.274A; as shown in Figure 19, the output voltage and current waveform diagram when the given phase shift angle is 120°, in the figure, when the output voltage U _o1 is about 38.24V, the corresponding output current is about 0.478A, and the output voltage U _o2 When the output current is about 38.24V, the corresponding output current is about 0.478A; as shown in Figure 20, the output voltage and current waveform diagram when the given phase shift angle is 180°, in the figure, when the output voltage U _o1 is about 44.59V, the corresponding output current is about 0.557A, when the output voltage U _o2 is about 44.59V, the corresponding output current is about 0.557A; it can be seen from the above that, changing the phase shift angle, the output current will increase with the increase of the phase shift angle, and the output current The accuracy can be kept within 5%, and the output has high current accuracy.

Embodiment three

In this embodiment, the closed control process of this solution is described in conjunction with various simulation diagrams of the circuit shown in FIG. 6 under closed-loop control.

When there is a large change in the input voltage, when the given reference current is 0.55A, the simulation waveform diagram of the output voltage and current after stabilization. U _o1 and U _o2 represent output voltages of any two LED strings respectively, and I _o1 and I _o2 represent output currents of corresponding branches respectively. Figure 21 is the waveform diagram when the input voltage is 64V. In the figure, when the output voltage U _o1 is about 44V, the corresponding output current is about 0.55A, and when the output voltage U _o2 is about 44V, the corresponding output current is about 0.55A; Figure 22 is a waveform diagram when the input voltage is 80V. In the figure, when the output voltage U _o1 is about 44V, the corresponding output current is about 0.55A, and when the output voltage U _o2 is about 44V, the corresponding output current is about 0.55A; as shown in the figure 23 is a waveform diagram when the input voltage is 120V. In the figure, when the output voltage U _o1 is about 44V, the corresponding output current is about 0.55A, and when the output voltage U _o2 is about 44V, the corresponding output current is about 0.55A. It can be seen from the above that in the closed-loop working mode, the output current accuracy can be kept within 0.02% (0.54993A-0.55008A) when the input and output voltages vary within a large range, and the output has high current accuracy.

U _o1 and I _o1 , U _o2 and I _o2 represent the output voltage and current of any two LED branches. As shown in Figure 24, the output voltage and current waveform diagram when the input voltage suddenly increases from 80V to 120V, at this time, the branch voltage U _o1 gradually increases from 44V to 47V, then drops to 44V and remains stable, and the current I _o1 rises to 0.59A , and then gradually stabilize back to the initial value of 0.55A, and the voltage and current stabilization time is 0.02s; the output voltage U _o2 gradually increases from 44V to 47V, the output current I _o2 rises to 0.59A, and then gradually stabilizes back to the initial value of 0.55A, the stabilization time is 0.02s; as shown in Figure 25, the output voltage and current waveform diagram when the input voltage suddenly drops from 80V to 64V, at this time the branch voltage U _o1 gradually decreases from 44V to 42V, then rises to 44V and remains stable, and the current I _o1 decreases to 0.525A then gradually stabilized back to the initial value of 0.55A, and the voltage and current stabilization time was 0.03s; the output voltage U _o2 gradually decreased from 44V to 42V, then rose to 44V and remained stable, and the current I _o2 decreased to 0.525A and then gradually stabilized back to the initial value The value is 0.55A, and the voltage and current stabilization time is 0.03s; From the above, it can be seen that in the closed-loop working mode, the output voltage and current have a fast recovery speed and strong anti-interference.

The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still implement the foregoing Modifications to the technical solutions described in the examples, or equivalent replacement of some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the application, and should be included in the Within the protection scope of this application.

Claims (9)

1. The utility model provides a multichannel wireless power transmission LED drive circuit based on constant current source compensation network which characterized in that: the receiving end comprises a plurality of paths of constant current output units, each path of constant current output unit is connected through a non-contact transformer, and the input end of the first constant current output unit is also connected through a non-contact transformer T _m The transmitting end comprises a DC/AC inversion unit and a passive resonance constant current unit, the constant current output unit comprises an AC/DC rectification unit and an LED load string, the output end of a power supply is connected with the input end of the DC/AC inversion unit, the output end of the DC/AC inversion unit is connected with the input end of the passive resonance constant current unit, and the output end of the passive resonance constant current unit is in contact-free transformation with the output end of the passive resonance constant current unitPressure device T _m Is connected on the primary side, the contactless transformer T _m The secondary side of the constant current output unit is connected with an AC/DC rectifying unit of the first constant current output unit, the output end of the AC/DC rectifying unit is connected with the LED load string, and each path of constant current output unit comprises a plurality of AC/DC rectifying units which are connected in series and a plurality of LED load strings which are in one-to-one correspondence with each AC/DC rectifying unit.

2. The multi-path wireless power transmission LED driving circuit based on the constant current source compensation network of claim 1, wherein: the DC/AC inversion unit is a full-bridge inversion network comprising a switch tube S ₁ -S ₄ Switching tube S ₁ 、S ₃ Respectively connected with a switch tube S ₂ 、S ₄ Of the substrate.

3. The multi-path wireless power transmission LED driving circuit based on the constant current source compensation network as claimed in claim 1, wherein: the passive resonance constant current unit is an LCL-T type network and comprises an inductorL _am An inductorL _bm And a capacitorC _m Said inductorL _bm One end of the non-contact transformer T _m The same name end of the primary side and the other end are connected with a capacitor simultaneouslyC _m And an inductorL _am One terminal of (1), a capacitorC _m The other end of the transformer is connected with a non-homonymous end of the primary side of the transformer, namely an inductorL _am And the other end of the DC/AC inverter unit is connected with the output end of the DC/AC inverter unit.

4. The multi-path wireless power transmission LED driving circuit based on the constant current source compensation network as claimed in claim 1, wherein: the AC/DC rectifying unit includes a diode D _ij ~D _（i+3）j And a capacitorC _oji Said diode D _ij Anode of (2), diode D _（i+1）j Cathode and contactless transformer T _j Is connected to the secondary side of a diode D _ij And D _（i+2）j Is connected to the cathode of the capacitorC _oji Is connected to one end of a capacitorC _oji Is connected with the positive end of the LED load string, and a diode D _（i+1）j 、D _（i+3）j Anode and capacitor ofC _oji Is connected to the other end of the capacitorC _oji The other end of the LED load string is connected with the negative end of the LED load string;

the constant current output units of the receiving end are s-m +1 paths, the number of the AC/DC rectification units arranged in each constant current output unit is n, i is any natural number from 1 to n, and j is any natural number from m to s.

5. The multi-path wireless power transmission LED driving circuit based on the constant current source compensation network as claimed in claim 1, wherein: the PWM control signal output end of the first pulse width modulator is connected with the input end of the phase-shifting modulation unit, the output end of the phase-shifting modulation unit is connected with the input end of the first driver, and the output end of the first driver is connected with the control signal input end of the DC/AC inversion unit.

6. The multi-path wireless power transmission LED driving circuit based on the constant current source compensation network of claim 1, wherein: the LED load string control circuit comprises an adder, a compensator, a second pulse width modulator and a second driver, wherein a sampling current output end and a reference current input end of the LED load string are connected with the input end of the adder, the output end of the adder is connected with the input end of the compensator, the output end of the compensator is connected with the input end of the second pulse width modulator, a PWM control signal output end of the second pulse width modulator is connected with the input end of the second driver, and the output end of the second driver is connected with a control signal input end of a DC/AC inversion unit.

7. The multi-path wireless power transmission LED driving circuit based on the constant current source compensation network according to claim 3, wherein: said is free ofInternal inductor of source resonance constant current unitL _am Inductance value of greater than inductanceL _bm The sensitivity value of (1).

8. The multi-path wireless power transmission LED driving circuit based on the constant current source compensation network according to claim 5, wherein: when the first pulse width modulator outputs a specified duty ratio K, the phase shift angle is adjusted within the range of 0 to 180 degrees through the phase shift modulation unit, so that the output current of the LED load string is kept within a specified precision.

9. The multi-path wireless power transmission LED driving circuit based on the constant current source compensation network as claimed in claim 6, wherein the control method of the closed loop control circuit comprises:

the summator calculates the sampling current of the LED load stringILED and reference currentICurrent error of refIerr，ILED-Iref=Ierr；

When in useIerr>At 0, the output value of the compensatorXIncreasing, and adjusting the duty ratio of the PWM control signal to increase by the second pulse width modulator;

when the temperature is higher than the set temperatureIerr<When 0, the output value of the compensatorXAnd decreasing, the second pulse width modulator adjusts the duty cycle of the PWM control signal to decrease.

Images