A wireless charging power converter and power conversion method thereof

Abstract

The present invention provides a wireless charging power converter, comprising: a power input end, a full-bridge boost circuit connected to the power input end, a transformer connected to the full-bridge boost circuit, a bridge rectifier circuit connected to the transformer, and a power output end connected to the bridge rectifier circuit. The full-bridge boost circuit comprises: a second MOS tube, a third MOS tube, and a power input end that forms a loop with the primary coil of the transformer, a first MOS tube, a first inductor, a fourth MOS tube, and a first capacitor. The source of the second MOS tube is connected to the output end of the first inductor and the drain is grounded, the source of the third MOS tube is electrically connected to the output end of the first inductor and the drain is grounded, and the negative pole of the power input end is grounded. By orderly controlling the four MOS tubes and coordinating the energy storage characteristics of the first inductor and the first capacitor, the power input of the power input end can be raised and alternating current can be realized. In addition, the structure is simple, the cost is low, and there is no diode on the primary side of the transformer to lose power, which can reduce the loss.

Description

[Technical field]

[0001] The present invention relates to the technical field of charging, and in particular to a wireless charging power converter. [Background technology]

[0002] As we all know, wireless charging is mostly achieved by energizing the primary coil. Under the action of electromagnetic induction, the secondary coil generates current, and the electric energy is transferred from the primary coil to the secondary coil. At present, in order to achieve high-voltage energy transmission in wireless charging, a boost power converter needs to be added to one side of the primary coil. The input voltage is pulled up by the boost power converter and then wireless high-voltage energy transmission is achieved through a full-bridge circuit. However, at present, the existing boost power converter generally uses an inductor in combination with a MOS tube and a diode to achieve boosting in advance, and then converts the boosted DC into AC in conjunction with an inverter. The structure is complex, costly, and the use of a diode will cause a voltage drop when it is turned on, thereby reducing the efficiency of the overall system.

[0003] Therefore, the existing technology needs to be improved and developed. [Summary of the invention]

[0004] The object of the present invention is to provide a wireless charging power converter to solve the problems of the existing boost power converters, such as complex structure, high cost and low overall system conversion rate.

[0005] The technical solution of the present invention is as follows: A wireless charging power converter comprises: a power input terminal for inputting power, a full-bridge boost circuit electrically connected to the power input terminal, a transformer electrically connected to the full-bridge boost circuit, a bridge rectifier circuit electrically connected to the transformer, and a power output terminal electrically connected to the bridge rectifier circuit; the full-bridge boost circuit is used to boost the voltage input from the power input terminal and transmit it to the transformer;

[0006] The full-bridge boost circuit comprises: a second MOS tube, a third MOS tube, and a power input end forming a loop with a primary coil of a transformer, a first MOS tube, a first inductor, a fourth MOS tube, and a first capacitor; the power input end, the first MOS tube, the first inductor, the fourth MOS tube, the first capacitor and the primary coil of the transformer are connected end to end in sequence, the source of the second MOS tube is connected to the output end of the first inductor and the drain is grounded, the source of the third MOS tube is electrically connected to the output end of the first inductor and the drain is grounded, and the negative electrode of the power input end is grounded; by orderly controlling the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube and cooperating with the energy storage characteristics of the first inductor and the first capacitor, the voltage inputted from the power input end is boosted and then transmitted to the transformer.

[0007] Furthermore, the power converter also includes a second inductor and a third capacitor, wherein two ends of the second inductor are electrically connected to the bridge rectifier circuit and the power supply output end respectively, and one end of the third capacitor is electrically connected to the output end of the second inductor and the other end is electrically connected to the bridge rectifier circuit.

[0008] Furthermore, the electric energy converter also includes a second capacitor, and two ends of the second capacitor are electrically connected to the secondary coil of the transformer and the bridge rectifier circuit respectively.

[0009] Furthermore, the electric energy converter also includes a freewheeling diode, a first pin of the freewheeling diode is electrically connected to the bridge rectifier circuit, and the other end of the freewheeling diode is electrically connected to the input end of the second inductor.

[0010] Furthermore, the bridge rectifier circuit includes a first diode, a second diode, a third diode and a fourth diode, the input ends of the first diode and the fourth diode are both grounded, the output end of the first diode is respectively connected to the second capacitor and the input end of the second diode, the output end of the second diode is respectively connected to the output end of the third diode and the input end of the second inductor, and the output end of the fourth diode is connected to an end of the secondary coil on the transformer away from the second capacitor.

[0011] Furthermore, the orderly control includes:

[0012] Step 1: At time t 0 -t 1 The first MOS tube and the third MOS tube are turned on at the same time, and a loop is formed between the power input terminal, the first MOS tube, the first inductor, and the third MOS tube, wherein the first inductor stores energy;

[0013] Step 2: At time t 1 -t 2 The third MOS tube is disconnected and the fourth MOS tube is turned on at the same time, and a loop is formed between the power input terminal, the first MOS tube, the first inductor, the fourth MOS tube, the first capacitor and the primary coil of the transformer; wherein the electric energy on the first inductor is transmitted to the secondary coil of the transformer via the fourth MOS tube, the first capacitor and the primary coil of the transformer in sequence, and is output via the second capacitor, the second diode, the second inductor and the power output terminal in sequence; wherein the second inductor stores energy;

[0014] Step 3: At time t 2 -t 3The first MOS tube is disconnected and the second MOS tube is turned on at the same time, a loop is formed between the first inductor, the second MOS tube, the primary coil of the transformer, the first capacitor, and the fourth MOS tube, the electric energy on the first inductor is transmitted to the secondary coil of the transformer via the second MOS tube and the primary coil of the transformer in sequence, a loop is formed between the secondary coil of the transformer and the fourth diode, the third diode, the second inductor, the power output end, the first diode, and the second capacitor, and the electric energy generated by the secondary coil of the transformer is rectified by the fourth diode and the third diode and then output via the second inductor;

[0015] Step 4: Repeat step 1, disconnect the second MOS tube and the fourth MOS tube, and turn on the first MOS tube and the third MOS tube at the same time, and form a loop between the power input terminal, the first MOS tube, the first inductor, and the third MOS tube. The first inductor stores energy; the second inductor, the power output terminal, and the freewheeling diode form a loop, and the electric energy on the second inductor is output from the power output terminal.

[0016] Furthermore, the first MOS tube, the second MOS tube, the third MOS tube, and the fourth MOS tube are all connected in parallel with a fifth diode and a fourth capacitor.

[0017] The beneficial effect of the present invention is that compared with the prior art, the full-bridge boost circuit of the present invention realizes energy storage in the first inductor and then transmits electric energy to the primary coil of the transformer through the first inductor and the first MOS tube, the second MOS tube, the third MOS tube, and the fourth MOS tube that are orderly controlled, so as to realize the power input by the power input end and realize the fixed frequency AC power, and transmit it to the secondary coil of the transformer. The structure is simple, which can reduce the cost, and there is no diode on the primary side of the transformer to lose electric energy, which can reduce the loss of the conversion rate of the overall electric energy converter to improve the conversion rate.

Brief Description of the Drawings

[0018] Figure 1 A circuit diagram of the present invention;

[0019] Figure 2 For the present invention, 0 -t 1 Schematic diagram of time working status;

[0020] Figure 3 For the present invention, 1 -t 2 Schematic diagram of time working status;

[0021] Figure 4 For the present invention, 2 -t 3 Schematic diagram of time working status;

[0022] Figure 5 For the present invention, 3 -t 1 Schematic diagram of the time working status. [Specific implementation method]

[0023] The present invention will be further described below in conjunction with the accompanying drawings and implementation modes.

[0024] Please refer to the attached Figure 1-5 , a wireless charging power converter in an embodiment of the present invention.

[0025] The wireless charging power converter includes: a power input terminal 1 for inputting power, a full-bridge boost circuit 4 electrically connected to the power input terminal 1, a transformer 3 electrically connected to the full-bridge boost circuit 4, a bridge rectifier circuit 5 electrically connected to the transformer 3, and a power output terminal 2 electrically connected to the bridge rectifier circuit 5. The full-bridge boost circuit 4 is used to boost the voltage input from the power input terminal 1 and transmit it to the transformer 3. The full-bridge boost circuit 4 includes: a second MOS tube Q2, a third MOS tube Q3, and a primary coil L connected to the transformer 3. TX The power input terminal 1, the first MOS tube Q1, the first inductor Lm, the fourth MOS tube Q4, and the first capacitor Cr that form a loop TX , power input terminal 1, first MOS tube Q1, first inductor Lm, fourth MOS tube Q4, first capacitor Cr TX and the primary coil L of transformer 3 TX The first and the second MOS tubes Q1, Q2, Q3 and Q4 are connected in sequence. The source of the second MOS tube Q2 is connected to the output end of the first inductor Lm, and the drain is grounded. The source of the third MOS tube Q3 is electrically connected to the output end of the first inductor Lm, and the drain is grounded. The negative electrode of the power input terminal 1 is grounded. Through the orderly control of the first MOS tube Q1, the second MOS tube Q2, the third MOS tube Q3 and the fourth MOS tube Q4 and the coordination of the first inductor Lm and the first capacitor Cr TX The energy storage characteristic of the power supply input terminal 1 is used to step up the voltage input thereto and transmit it to the transformer 3.

[0026] The full-bridge boost circuit 4 of the present invention realizes storing energy in the first inductor Lm and then supplying energy to the primary coil L of the transformer 3 through the first MOS transistor Q1, the second MOS transistor Q2, the third MOS transistor Q3 and the fourth MOS transistor Q4 which are controlled in an orderly manner. TX Transmit electrical energy to achieve the power supply inputted by the power supply input terminal 1 and realize the fixed frequency alternating current, and transmit it to the secondary coil L of the transformer 3 RX The structure is simple and can reduce costs. There is no diode on the primary side of the transformer 3 to lose electric energy, which can reduce the loss of the conversion rate of the overall electric energy converter, thereby improving the conversion rate and solving the problems of the prior art.

[0027] In one embodiment, the power converter further includes a second inductor L 0 And the third capacitor C 0 , the second inductor L 0 The two ends of the third capacitor C are electrically connected to the bridge rectifier circuit 5 and the power output terminal 2 respectively. 0 One end of the second inductor L is connected to 0 The power converter also includes a freewheeling diode D f Tube, freewheeling diode D f The first pin of the tube is electrically connected to the bridge rectifier circuit 5, and the other end is electrically connected to the second inductor L 0 The second inductor L 0 , the primary coil L in transformer 3 TX The electrical energy is transmitted to the secondary coil L RX When the second inductor L 0 To store energy, the primary coil L TX No power is transferred to the secondary coil L RX When the freewheeling diode D f The second inductor L 0 , power output terminal 2, freewheeling diode D f The tubes form a loop, and the second inductor L 0 The electrical energy is output from the power output terminal 2.

[0028] In the above embodiment, the power converter further includes a second capacitor Cr RX , the second capacitor Cr RX The two ends of the transformer 3 are connected to the secondary coil L RX The bridge rectifier circuit 5 is electrically connected to the bridge rectifier circuit 5. The bridge rectifier circuit 5 includes a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4. The input end of the first diode D1 and the input end of the fourth diode D4 are both grounded. The output end of the first diode D1 is connected to the second capacitor Cr. RX The output end of the second diode D2 is connected to the output end of the third diode D3 and the second inductor L 0 The output end of the fourth diode D4 is connected to the secondary coil L of the transformer 3. RX Keep away from the second capacitor Cr RX At one end, the AC power generated by the transformer 3 is converted into DC power using a bridge rectifier circuit 5 composed of four diodes.

[0029] In order to protect the first MOS transistor Q1 , the second MOS transistor Q2 , the third MOS transistor Q3 , and the fourth MOS transistor Q4 , the first MOS transistor Q1 , the second MOS transistor Q2 , the third MOS transistor Q3 , and the fourth MOS transistor Q4 are all connected in parallel with a fifth diode and a fourth capacitor.

[0030] Specifically, in order to achieve voltage raising and reduce control difficulty, the orderly control includes:

[0031] Step 1: At time t 0 -t 1 The first MOS transistor Q1 and the third MOS transistor Q3 are turned on at the same time, and a loop is formed between the power input terminal 1, the first MOS transistor Q1, the first inductor Lm, and the third MOS transistor Q3. In this way, the direct current input from the power input terminal 1 can store energy in the first inductor Lm after passing through the first MOS transistor Q1.

[0032] Step 2: At time t 1 -t 2 The third MOS tube Q3 is disconnected, and the fourth MOS tube Q4 is turned on at the same time, the power input terminal 1, the first MOS tube Q1, the first inductor Lm, the fourth MOS tube Q4, the first capacitor CrTX and the primary coil Lm of the transformer 3 are connected. TX The power input from the power input terminal 1 and the electric energy stored in the first inductor Lm are sequentially transmitted through the fourth MOS tube Q4 and the first capacitor Cr. TX , the primary coil L of transformer 3 TX Transmitted to the secondary coil L of transformer 3 RX Then, through the second capacitor Cr RX , the second diode D2, the second inductor L 0 , the power supply output terminal 2 outputs, and the second inductor L 0 At this time, the voltage output by the first inductor Lm is the sum of the power input from the power input terminal 1 and the electric energy stored in the first inductor Lm.

[0033] Step 3: At time t 2 -t 3 The first MOS tube Q1 is disconnected, and the second MOS tube Q2 is turned on. The first inductor Lm, the second MOS tube Q2, and the primary coil L of the transformer 3 are TX 、The first capacitor Cr TX The electric energy on the first inductor Lm is sequentially transmitted through the second MOS transistor Q2, the primary coil L of the transformer 3, and the fourth MOS transistor Q4. TX Transmitted to the secondary coil L of transformer 3 RX , the secondary coil L of transformer 3 RX The fourth diode D4, the third diode D3, the second inductor L0 , power supply output terminal 2, first diode D1, second capacitor Cr RX A loop is formed between the secondary coil L of transformer 3. RX The generated electric energy is rectified by the fourth diode D4 and the third diode D3 and then passes through the second inductor L 0 Output.

[0034] Step 4: Repeat step 1, disconnect the second MOS tube Q2 and the fourth MOS tube Q4, and simultaneously turn on the first MOS tube Q1 and the third MOS tube Q3, and form a loop between the power input terminal 1, the first MOS tube Q1, the first inductor Lm, and the third MOS tube Q3. The first inductor Lm stores energy. And the second inductor L 0 , and the power supply output terminal 2, the freewheeling diode D f The tubes form a loop, and the second inductor L 0 The electric energy on the power supply is output from the power supply output terminal 2. Then, step 2 and step 3 are performed again and again, and the power supply output terminal 2 can output power continuously and stably.

[0035] Specifically, the power input to the power input terminal 1 is set to Vin, and the power output to the power output terminal 2 is set to V 0 , the current of the switch is I Lon The current cut off by the switch is represented by I Loff The duty cycle is represented by D, the period of the duty cycle is TS, and the inductor boost energy storage is represented by Lm, and the following formula can be obtained: I Lon =Vin*D*TS / Lm; I Loff =V 0 *(1-D)*TS / Lm.

[0036] And because the current on the inductor cannot change suddenly and according to the volt-second balance law of the inductor voltage, the volt-second balance law of the inductor voltage means that for a DC-DC power converter that has been working stably in a steady state, the forward volt-second applied to the inductor when the active switch is turned on must be equal to the reverse volt-second applied to the inductor when the active switch is turned off. It can be obtained that I Lon =I Loff , that is, Vin*D*TS / Lm=V 0 *(1-D)*TS / Lm, and by simplifying this, we can get V 0 =(Vin*D) / (1-D), which is different from the traditional wireless charging boost full-bridge power converter voltage gain of V 0 =(Vin*D) / (1-D), and can reduce components and parts, and cooperate with orderly control, which can reduce the control difficulty of the power converter of the present invention and effectively reduce the cost.

[0037] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope of the present invention.

Claims

1. A wireless charging power converter, characterized in that: include: A power input terminal for inputting power, a full-bridge boost circuit electrically connected to the power input terminal, a transformer electrically connected to the full-bridge boost circuit, a bridge rectifier circuit electrically connected to the transformer, and a power output terminal electrically connected to the bridge rectifier circuit; The full-bridge boost circuit is used to boost the voltage input from the power input terminal and transmit it to the transformer; The full-bridge boost circuit comprises: a second MOS tube, a third MOS tube, and a power input end forming a loop with a primary coil of a transformer, a first MOS tube, a first inductor, a fourth MOS tube, and a first capacitor; the power input end, the first MOS tube, the first inductor, the fourth MOS tube, the first capacitor and the primary coil of the transformer are connected end to end in sequence, the source of the second MOS tube is connected to the output end of the first inductor and the drain is grounded, the source of the third MOS tube is electrically connected to the output end of the first inductor and the drain is grounded, and the negative electrode of the power input end is grounded; by orderly controlling the first MOS tube, the second MOS tube, the third MOS tube and the fourth MOS tube and cooperating with the energy storage characteristics of the first inductor and the first capacitor, the voltage inputted from the power input end is boosted and then transmitted to the transformer; The orderly control includes: Step 1: between time t0 and time t1, the first MOS tube and the third MOS tube are turned on at the same time, and a loop is formed between the power input terminal, the first MOS tube, the first inductor, and the third MOS tube, wherein the first inductor stores energy; Step 2: between time t1 and t2, the third MOS tube is turned off, and the fourth MOS tube is turned on at the same time, so that a loop is formed between the power input terminal, the first MOS tube, the first inductor, the fourth MOS tube, the first capacitor and the primary coil of the transformer; wherein the electric energy on the first inductor is sequentially transmitted to the secondary coil of the transformer through the fourth MOS tube, the first capacitor and the primary coil of the transformer, and is sequentially output through the second capacitor, the second diode, the second inductor and the power output terminal; wherein the second inductor stores energy; Step 3: between time t2 and t3, the first MOS tube is turned off, and the second MOS tube is turned on at the same time, a loop is formed between the first inductor, the second MOS tube, the primary coil of the transformer, the first capacitor, and the fourth MOS tube, the electric energy on the first inductor is transmitted to the secondary coil of the transformer via the second MOS tube and the primary coil of the transformer in sequence, a loop is formed between the secondary coil of the transformer and the fourth diode, the third diode, the second inductor, the power output end, the first diode, and the second capacitor, and the electric energy generated by the secondary coil of the transformer is rectified by the fourth diode and the third diode and then output via the second inductor; Step 4: Repeat step 1, disconnect the second MOS tube and the fourth MOS tube, and turn on the first MOS tube and the third MOS tube at the same time, and form a loop between the power input end, the first MOS tube, the first inductor, and the third MOS tube, wherein the first inductor stores energy; and form a loop between the second inductor, the power output end, and the freewheeling diode, and the electric energy on the second inductor is output from the power output end.

2. The wireless charging power converter according to claim 1, characterized in that: The electric energy converter also includes a second inductor and a third capacitor, wherein two ends of the second inductor are electrically connected to the bridge rectifier circuit and the power supply output end respectively, and one end of the third capacitor is electrically connected to the output end of the second inductor and the other end is electrically connected to the bridge rectifier circuit.

3. The wireless charging power converter according to claim 2, characterized in that: The electric energy converter further includes a second capacitor, and two ends of the second capacitor are electrically connected to the secondary coil of the transformer and the bridge rectifier circuit respectively.

4. The wireless charging power converter according to claim 3, characterized in that: The electric energy converter also includes a freewheeling diode, a first pin of which is electrically connected to the bridge rectifier circuit, and the other end of which is electrically connected to the input end of the second inductor.

5. The wireless charging power converter according to claim 4, characterized in that: The bridge rectifier circuit includes a first diode, a second diode, a third diode and a fourth diode, the input ends of the first diode and the fourth diode are both grounded, the output end of the first diode is respectively connected to the second capacitor and the input end of the second diode, the output end of the second diode is respectively connected to the output end of the third diode and the input end of the second inductor, and the output end of the fourth diode is connected to an end of the secondary coil on the transformer away from the second capacitor.

6. The wireless charging power converter according to claim 5, characterized in that: The first MOS tube, the second MOS tube, the third MOS tube, and the fourth MOS tube are all connected in parallel with a fifth diode and a fourth capacitor.

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