High-gain conversion circuit and control method thereof

Abstract

The application discloses a high-gain conversion circuit and a control method thereof. The high-gain conversion circuit comprises a main circuit, a voltage detection circuit, a current detection circuit, a load prediction circuit, a main control circuit and a driving circuit, and the main circuit, the voltage detection circuit, the current detection circuit, the load prediction circuit, the main control circuit and the driving circuit are electrically connected in sequence. The high-gain conversion circuit can obtain a high boost gain without a high duty cycle, and solves the technical problem that a conversion device is difficult to obtain a high gain due to the influence of a control chip and parasitic parameters in a circuit.

Description

Technical Field

[0001] This invention relates to the field of DC power conversion technology, and in particular to a high-gain conversion circuit and its control method. Background Technology

[0002] Existing DC-DC converters are widely used in industrial production and daily life, for example:

[0003] 1. In distributed generation systems, converters are used to boost the output voltage of photovoltaic arrays to the DC bus voltage level of the power grid;

[0004] 2. In an uninterruptible power supply system, the output voltage of lead-acid batteries needs to be boosted to 380V to connect to the inverter bus.

[0005] Therefore, DC-DC converters have broad application prospects in power systems and other fields.

[0006] The Boost converter is a classic boost converter with a gain of [missing information]. Theoretically, the gain can be infinitely large if the duty cycle is infinitely small. However, it is limited by the maximum value of the control chip. Therefore, the duty cycle usually cannot exceed 0.85. Due to the influence of the control chip and parasitic parameters in the circuit, it is difficult for the boost converter to achieve high gain. In addition, existing step-up transformers such as Sepic converters and Zeta converters all have the same problem.

[0007] In addition, real-world operating conditions are complex and variable, making it difficult to effectively model the load of the DC-DC converter and thus unable to effectively provide the load value to the closed-loop control parameters of the DC-DC converter, resulting in the controller being unable to quickly track disturbance responses. Summary of the Invention

[0008] In order to solve the technical problems existing in the prior art, the present invention constructs a new high-gain converter that can obtain a high boost gain without requiring a high duty cycle, and can stably and effectively control it, and can effectively provide the load value to the closed-loop control parameters of the DC-DC converter.

[0009] To solve the above-mentioned technical problems, on the one hand, the present invention provides a high-gain conversion circuit, which includes a main circuit, a voltage detection circuit, a current detection circuit, a load prediction circuit, a main control circuit, and a drive circuit, wherein the main circuit, the voltage detection circuit, the current detection circuit, the load prediction circuit, the main control circuit, and the drive circuit are electrically connected in sequence.

[0010] The main circuit includes a first switch S1, a second switch S2, and a load R, which are electrically connected.

[0011] The voltage detection circuit is connected to the load R of the main circuit and the first input terminal of the load prediction circuit. The voltage detection circuit detects the load voltage Vo of the load R in the main circuit and sends it to the load detection circuit.

[0012] The second input terminal of the load prediction circuit is connected to the reference voltage V. ref Electrical connection, wherein the output terminal of the load prediction circuit is connected to the first input terminal of the main control circuit;

[0013] The second input terminal of the main control circuit is connected to the output terminal of the current detection circuit, the third input terminal of the main control circuit is electrically connected to the duty cycle reference value dref, the first output terminal of the main control circuit is connected to the first input terminal of the drive circuit, and the second output terminal of the main control circuit is connected to the second input terminal of the drive circuit.

[0014] The input terminal of the current detection circuit is electrically connected to the DC power supply Vin in the main circuit.

[0015] The first output terminal of the driving circuit is electrically connected to the gate of the first switching transistor S1 in the main circuit, and the second output terminal of the driving circuit is electrically connected to the gate of the second switching transistor S2 in the main circuit. The driving circuit outputs control signals PWM1 and PWM2 and sends the control signals to the first switching transistor S1 and the second switching transistor S2 in the main circuit, respectively. The main circuit controls the switching on and off of the first switching transistor S1 and the second switching transistor S2 through its output control signals PWM1 and PWM2 to stabilize the output voltage of the main circuit to the reference voltage V. ref .

[0016] In a further improvement to the above technical solution, the main circuit includes a DC power supply Vin, a first inductor L1, a second inductor L2, a third inductor L3, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, and a seventh diode D7.

[0017] The positive terminal of the DC power supply Vin is electrically connected to the first terminal of the first inductor L1, the positive terminal of the first diode D1, the first terminal of the third inductor L3, and the positive terminal of the seventh diode D7.

[0018] The second terminal of the second inductor L1 is electrically connected to the positive terminal of the second diode D2 and the positive terminal of the third diode D3;

[0019] The cathode of the first diode D1 is electrically connected to the anode of the second diode D2 and the first terminal of the second inductor L2;

[0020] The negative terminal of the third diode D3 is electrically connected to the second terminal of the second inductor L2, the first terminal of the second capacitor C2, the positive terminal of the fourth diode D4, and the drain of the first switching transistor S1.

[0021] The negative terminal of the fourth diode D4 is electrically connected to the first terminal of the first capacitor C1 and the positive terminal of the fifth diode D5.

[0022] The negative terminal of the fifth diode D5 is electrically connected to the second terminal of the second capacitor C2 and the positive terminal of the sixth diode D6.

[0023] The negative terminal of the sixth diode D6 is electrically connected to the first terminal of the third capacitor C3 and the first terminal of the load R.

[0024] To further improve the above technical solution, the main circuit also includes a fourth inductor L4, a fifth inductor L5, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, an eighth diode D8, a ninth diode D9, and a tenth diode D10. 10 11th diode D 11 12th diode D 12 ;

[0025] The second terminal of the third inductor L3 is connected to the positive terminal of the eighth diode D8 and the first terminal of the fourth capacitor C4.

[0026] The negative terminal of the seventh diode D7 is electrically connected to the second terminal of the fourth capacitor C4 and the first terminal of the fourth inductor L4.

[0027] The negative terminal of the eighth diode D8 is connected to the second terminal of the fourth inductor L4, the positive terminal of the first terminal of the ninth diode D9, and the tenth diode D... 10 The first terminal is electrically connected to the positive electrode;

[0028] The negative terminal of the ninth diode D9 is electrically connected to the first terminal of the fifth capacitor C5 and the first terminal of the fifth inductor L5.

[0029] The tenth diode D 10 The negative terminal of the transistor is connected to the second terminal of the fifth inductor L5, the drain of the second switch S2, and the eleventh diode D. 11 The positive terminal is electrically connected;

[0030] The second terminal of the sixth capacitor C6 is connected to the twelfth diode D. 12 The positive terminal and the second terminal of the load R are electrically connected;

[0031] The negative terminal of the DC power supply Vin is connected to the source of the first switching transistor S1, the second terminal of the first capacitor C1, the second terminal of the third capacitor C3, and the eleventh diode D. 11 The second terminal, the first terminal of the sixth capacitor C6, the second terminal of the fifth capacitor C5, the source of the second switch S2, and the twelfth diode D 12 The negative terminal is electrically connected.

[0032] To further improve the above technical solution, the control signals PWM1 and PWM2 output by the driving circuit have two modes, namely mode 1 and mode 2. Mode 1 occurs when control signals PWM1 and PWM2 are at high levels (Vgs1 and Vgs2), with both the first switch S1 and the second switch S2 turned on. The DC power supply Vin charges the first inductor L1, the second inductor L2, the third inductor L3, the fourth inductor L4, and the fourth capacitor C4; the first capacitor C1 charges the second capacitor C2; the fifth capacitor C5 charges the fifth inductor L5; and the third capacitor C3 and the sixth capacitor C6 charge the load R. Mode 2... When control signals PWM1 and PWM2 are at low levels (Vgs1 and Vgs2 respectively), and the first switch S1 and the second switch S2 are both off, the DC power supply Vin, the first inductor L1, and the second inductor L2 charge the first capacitor C1; the DC power supply Vin, the third inductor L3, the fourth inductor L4, and the fourth capacitor C4 charge the fifth capacitor C5; the DC power supply Vin, the third inductor L3, the fourth inductor L4, the fifth inductor L5, and the fourth capacitor C4 charge the sixth capacitor C6 and the load R; and the DC power supply Vin, the first inductor L1, the second inductor L2, and the second capacitor C2 charge the third capacitor C3 and the load R.

[0033] Further improvements to the above technical solution involve the driving circuit operating in Mode 1 and Mode 2, where L1 = L2, L3 = L4, d1 = d2, L1 is the inductance value of the first inductor L1, L2 is the inductance value of the second inductor L2, L3 is the inductance value of the third inductor L3, and L4 is the inductance value of the fourth inductor L4. d1 is the duty cycle of PWM1, and d2 is the duty cycle of PWM2. The inductor voltage values ​​calculated under these two modes are:

[0034]

[0035]

[0036] And there are:

[0037]

[0038] V C4=V in

[0039] V o =V C3 +V C6

[0040] Based on the volt-second balance theorem of inductance and the above formula, the voltage gain G can be derived as:

[0041] Voltage gain

[0042] On the other hand, the present invention also provides a control method for a high-gain converter circuit, which uses the high-gain converter circuit as described in claim 1 for control, and the control method includes the following steps:

[0043] Step 1) The voltage detection circuit detects the voltage V of the main circuit load. o The current is then fed into the load detection circuit, and the current detection circuit detects the input current I of the main circuit. in And send it to the main control circuit;

[0044] Step 2) The load detection circuit detects the load voltage V. o and reference voltage V ref Calculate the load forecast value I p And send it to the main control circuit;

[0045] Step 3) The main control circuit determines the load prediction value I based on the load prediction value. p Input current I in and duty cycle reference value D ref Perform the operation d1 = D ref -K1(I in -I p ) and d2=D ref -K2(I in -I p The data is fed into the drive circuit, where K1 and K2 are control coefficients.

[0046] Step 4) The driving circuit generates control signals PWM1 and PWM2 based on d1 and d2, and sends PWM1 to the gate of the first switching transistor S1 in the main circuit, and sends PWM2 to the gate of the second switching transistor S2 in the main circuit.

[0047] Step 5) Control the first switching transistors S1 and S2 to turn on and off according to control signals PWM1 and PWM2, so that the output voltage can be stabilized at the reference voltage V. ref .

[0048] Compared with existing technologies, the high-gain conversion circuit and its control method of the present invention have at least the following technical advantages:

[0049] (1) The high-gain conversion circuit of the present invention includes a main circuit, a voltage detection circuit, a current detection circuit, a load prediction circuit, a main control circuit, and a drive circuit. The main circuit, voltage detection circuit, current detection circuit, load prediction circuit, main control circuit, and drive circuit are electrically connected in sequence. The main circuit includes a first switch S1, a second switch S2, and a load R. The first switch S1, the second switch S2, and the load R are electrically connected. The first output terminal of the drive circuit is electrically connected to the gate of the first switch S1 in the main circuit, and the second output terminal of the drive circuit is electrically connected to the gate of the second switch S2 in the main circuit. The system outputs control signals PWM1 and PWM2 and sends these signals to the first switch S1 and the second switch S2 in the main circuit, respectively. The main circuit of this invention includes a DC power supply Vin, a first inductor L1, a second inductor L2, a third inductor L3, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, a fourth inductor L4, a fifth inductor L5, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, an eighth diode D8, a ninth diode D9, and a tenth diode D1. 10 11th diode D 11 12th diode D 12 The voltage gain G obtained by the high-gain conversion circuit of the present invention is Therefore, the high-gain converter circuit of the present invention can achieve a high boost gain without requiring a very high duty cycle, thus solving the technical problem that existing converters are unable to achieve high gain due to the influence of parasitic parameters in the control chip and circuit.

[0050] (2) The high-gain conversion circuit control method of this invention includes detecting the voltage V of the main circuit load through a voltage detection circuit. o The current is then fed into the load detection circuit, and the current detection circuit detects the input current I of the main circuit. in And it is sent to the main control circuit, and the load detection circuit detects the load voltage V. o and reference voltage V ref Calculate the load forecast value I p And it is sent to the main control circuit, which then uses the load prediction value I. p Input current I in and duty cycle reference value D refThe calculations are performed and sent to the drive circuit. The drive circuit generates control signals PWM1 and PWM2 based on d1 and d2. PWM1 is sent to the gate of the first switching transistor S1 in the main circuit, and PWM2 is sent to the gate of the second switching transistor S2 in the main circuit. The control signals PWM1 and PWM2 are used to control the conduction and disconnection of the first switching transistors S1 and S2, thereby stabilizing the output voltage to the reference voltage V. ref The control method of this invention can predict the load value when the load is unknown or changes, and then stably control the circuit, making the circuit more robust. It solves the technical problem that existing DC-DC converters cannot effectively provide the load value to the closed-loop control parameters of the DC-DC converter due to the complexity and variability of real-world operating conditions, resulting in the controller's inability to quickly track disturbances. Attached Figure Description

[0051] The high-gain conversion circuit and its control method of the present invention, as well as their technical effects, will be described in detail below with reference to the accompanying drawings and embodiments, wherein:

[0052] Figure 1 This is a circuit diagram of the high-gain conversion circuit of the present invention;

[0053] Figure 2 This is the equivalent circuit diagram of mode 1 in embodiment two of the high-gain conversion circuit of the present invention;

[0054] Figure 3 This is the equivalent circuit diagram of mode 2 in embodiment two of the high-gain conversion circuit of the present invention;

[0055] Figure 4 This is a flowchart illustrating the control method of the high-gain conversion circuit of the present invention;

[0056] Figure 5 This is a simulation waveform diagram of the high-gain conversion circuit of the present invention. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0058] like Figure 1As shown, Embodiment 1 of the present invention provides a high-gain conversion circuit, which includes a main circuit, a voltage detection circuit, a current detection circuit, a load prediction circuit, a main control circuit, and a drive circuit. The main circuit, voltage detection circuit, current detection circuit, load prediction circuit, main control circuit, and drive circuit are electrically connected in sequence.

[0059] The main circuit includes a first switch S1, a second switch S2, and a load R, which are electrically connected.

[0060] The voltage detection circuit is connected to the load R of the main circuit and the first input terminal of the load prediction circuit. The voltage detection circuit detects the load voltage Vo of the load R in the main circuit and sends it to the load detection circuit.

[0061] The second input terminal of the load prediction circuit is connected to the reference voltage V. ref Electrically connected, the output of the load prediction circuit is connected to the first input of the main control circuit. The load detection circuit determines the load voltage Vo and the reference voltage V. ref The load prediction value Ip is calculated and sent to the main control circuit;

[0062] The second input terminal of the main control circuit is connected to the output terminal of the current detection circuit, the third input terminal of the main control circuit is electrically connected to the duty cycle reference value dref, the first output terminal of the main control circuit is connected to the first input terminal of the drive circuit, and the second output terminal of the main control circuit is connected to the second input terminal of the drive circuit.

[0063] The input terminal of the current detection circuit is electrically connected to the DC power supply Vin in the main circuit.

[0064] The first output terminal of the drive circuit is electrically connected to the gate of the first switching transistor S1 in the main circuit, and the second output terminal of the drive circuit is electrically connected to the gate of the second switching transistor S2 in the main circuit. The drive circuit outputs control signals PWM1 and PWM2 and sends these control signals to the first switching transistor S1 and the second switching transistor S2 in the main circuit, respectively. The main circuit uses its output control signals PWM1 and PWM2 to control the switching on and off of the first switching transistor S1 and the second switching transistor S2, so that the output voltage of the main circuit is stabilized at the reference voltage V. ref .

[0065] In a preferred embodiment of the present invention, the main circuit includes a DC power supply Vin, a first inductor L1, a second inductor L2, a third inductor L3, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, and a seventh diode D7. The main circuit also includes a fourth inductor L4, a fifth inductor L5, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, an eighth diode D8, a ninth diode D9, and a tenth diode D1. 10 11th diode D 11 12th diode D 12 Connect the positive terminal of the DC power supply Vin to the first terminal of the first inductor L1, the positive terminal of the first diode D1, the first terminal of the third inductor L3, and the positive terminal of the seventh diode D7. Connect the second terminal of the second inductor L1 to the positive terminals of the second diode D2 and the third diode D3. Connect the negative terminal of the first diode D1 to the positive terminal of the second diode D2 and the first terminal of the second inductor L2. Connect the negative terminal of the third diode D3 to the second terminal of the second inductor L2, the first terminal of the second capacitor C2, the positive terminal of the fourth diode D4, and the drain of the first switching transistor S1. Connect the negative terminal of the fourth diode D4 to the first terminal of the first capacitor C1 and the positive terminal of the fifth diode D5. Connect the negative terminal of the fifth diode D5 to the second terminal of the second capacitor C2 and the positive terminal of the sixth diode D6. Connect the negative terminal of the sixth diode D6 to the first terminal of the third capacitor C3 and the first terminal of the load R. The second terminal of the third inductor L3 is connected to the positive terminal of the eighth diode D8 and the first terminal of the fourth capacitor C4; the negative terminal of the seventh diode D7 is electrically connected to the second terminal of the fourth capacitor C4 and the first terminal of the fourth inductor L4; the negative terminal of the eighth diode D8 is connected to the second terminal of the fourth inductor L4, the positive terminal of the first terminal of the ninth diode D9, and the tenth diode D... 10 The first terminal of diode D9 is electrically connected to the positive terminal; the negative terminal of diode D9 is electrically connected to the first terminal of capacitor C5 and inductor L5; the tenth diode D... 10 The negative terminal of the transistor is connected to the second terminal of the fifth inductor L5, the drain of the second switch S2, and the eleventh diode D. 11 The positive terminal is connected; the second terminal of the sixth capacitor C6 is connected to the twelfth diode D. 12 The positive terminal of the capacitor is electrically connected to the second terminal of the load R; the negative terminal of the DC power supply Vin is connected to the source of the first switching transistor S1, the second terminal of the first capacitor C1, the second terminal of the third capacitor C3, and the eleventh diode D. 11 The second terminal, the first terminal of the sixth capacitor C6, the second terminal of the fifth capacitor C5, the source of the second switch S2, and the twelfth diode D 12The negative terminal is electrically connected. In a specific implementation of the present invention, the first switch S1 and the second switch S2 are NMOS transistors. The Boost circuit composed of the inductor, switch, capacitor and diode in the main circuit not only charges the load R, but also protects the circuit, preventing the large induced voltage generated by the inductor coil from damaging the switch and affecting the circuit when the first switch S1 or the second switch S2 is turned off.

[0066] Example 2: When L1 = L2, L3 = L4, d1 = d2, and all inductors are sufficiently large, where L1 is the inductance value of the first inductor L1, L2 is the inductance value of the second inductor L2, L3 is the inductance value of the third inductor L3, L4 is the inductance value of the fourth inductor L4, d1 is the duty cycle of PWM1, and d2 is the duty cycle of PWM2, taking the circuit operating in CCM mode as an example, the circuit has two operating modes, as detailed below:

[0067] like Figure 2 As shown, when the circuit operates in mode 1, mode 1 is when the control signals PWM1 and PWM2 are at high levels Vgs1 and Vgs2. The inductor voltage values ​​calculated under these two modes are as follows: When the circuit operates in mode 1, both the first switch S1 and the second switch S2 are turned on. The DC power supply Vin charges the first inductor L1, the second inductor L2, the third inductor L3, the fourth inductor L4, and the fourth capacitor C4. The first capacitor C1 charges the second capacitor C2. The fifth capacitor C5 charges the fifth inductor L5. The third capacitor C3 and the sixth capacitor C6 charge the load R. The inductor currents iL1, iL2, iL3, iL4, iL5, and iL6 increase linearly.

[0068] like Figure 3 As shown, when the circuit operates in mode 2, which is when the control signals PWM1 and PWM2 are at low levels (Vgs1 and Vgs2 respectively), and both the first switch S1 and the second switch S2 are off, the DC power supply Vin, the first inductor L1, and the second inductor L2 charge the first capacitor C1; the DC power supply Vin, the third inductor L3, the fourth inductor L4, and the fourth capacitor C4 charge the fifth capacitor C5; the DC power supply Vin, the third inductor L3, the fourth inductor L4, the fifth inductor L5, and the fourth capacitor C4 charge the sixth capacitor C6 and the load R; and the DC power supply Vin, the first inductor L1, the second inductor L2, and the second capacitor C2 charge the third capacitor C3 and the load R. The inductor currents iL1, iL2, iL3, iL4, iL5, and iL6 decrease linearly.

[0069] The calculated inductor voltage values ​​are as follows, assuming the circuit operates in mode 1 and mode 2:

[0070]

[0071] And there are:

[0072]

[0073] V C4 =V in

[0074] V o =V C3 +V C6

[0075] Based on the volt-second balance theorem of inductance and the above formula, the voltage gain G can be derived as:

[0076] Voltage gain

[0077] Therefore, the high-gain converter circuit of the present invention can achieve a high boost gain without requiring a very high duty cycle.

[0078] Example 3:

[0079] like Figure 4 As shown, the present invention also provides a control method for a high-gain converter circuit, which uses the high-gain converter circuit as described in claim 1 for control. This control method includes the following steps:

[0080] Step 1) The voltage detection circuit detects the voltage V of the main circuit load. o The current is then fed into the load detection circuit, and the current detection circuit detects the input current I of the main circuit. in And send it to the main control circuit;

[0081] Step 2) The load detection circuit detects the load voltage V. o and reference voltage V ref Calculate the load forecast value I p And send it to the main control circuit;

[0082] Step 3) The main control circuit determines the load prediction value I based on the load prediction value. p Input current I in and duty cycle reference value D ref Perform the operation d1 = D ref -K1(I in -I p ) and d2=D ref -K2(I in -I p The data is fed into the drive circuit, where K1 and K2 are control coefficients.

[0083] Step 4) The driving circuit generates control signals PWM1 and PWM2 based on d1 and d2, and sends PWM1 to the gate of the first switching transistor S1 in the main circuit, and sends PWM2 to the gate of the second switching transistor S2 in the main circuit.

[0084] Step 5) Control the first switching transistors S1 and S2 to turn on and off according to control signals PWM1 and PWM2, so that the output voltage can be stabilized at the reference voltage V. ref .

[0085] Example 4: Figure 5 The figure shows the simulation results of the boost gain obtained by the converter using the converter circuit of this invention. The parameters involved in the simulation are as follows:

[0086] Vin=10V; L1=200uH; L2=200uH; L3=100uH; L4=100uH; L5=330uH; C1=100uF;

[0087] C2=100uF; C3=100uF; C4=47uF; C5=47uF; C6=330uF; d=0.5.

[0088] The simulation waveform obtained using the above parameters is shown below. Figure 5 As shown, Vgs1 is the drive signal for the first switch S1; Vgs2 is the drive signal for the second switch S2; iL1 is the current waveform of the first inductor L1; iL2 is the current waveform of the second inductor L2; iL3 is the current waveform of the third inductor L3; iL4 is the current waveform of the fourth inductor L4; iL5 is the current waveform of the fifth inductor L5; and Vo is the waveform of the converter's output voltage.

[0089] The simulation results from the waveform diagram show that the converter has extremely high gain, achieving a boost effect of 14 times at a duty cycle of 0.5.

[0090] Compared with the prior art, the technical solution disclosed in the above embodiments has the following beneficial effects:

[0091] In the above embodiments, the voltage gain G obtained by the high-gain conversion circuit of the present invention is: This invention enables high boost gain without requiring a high duty cycle, addressing the technical problem of existing boost converters struggling to achieve high gains due to the influence of parasitic parameters in the control chip and circuitry. The control method of this invention can predict the load value even when the load is unknown or changing, thereby enabling stable circuit control and enhancing circuit robustness. It also solves the technical problem of existing DC-DC converters failing to effectively provide load values ​​to the closed-loop control parameters due to the complexity and variability of real-world operating conditions, resulting in the controller's inability to quickly track disturbances.

[0092] The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A high gain conversion circuit including a conversion circuit that corrects a user's sitting posture, characterized by: The high-gain conversion circuit comprises a main circuit, a voltage detection circuit, a current detection circuit, a load prediction circuit, a main control circuit and a driving circuit, and the main circuit, the voltage detection circuit, the current detection circuit, the load prediction circuit, the main control circuit and the driving circuit are sequentially connected by electricity; The main circuit comprises a first switch tube S1, a second switch tube S2 and a load R, and the first switch tube S1, the second switch tube S2 and the load R are connected by electricity; The voltage detection circuit is connected with the load R of the main circuit and the first input end of the load prediction circuit, detects the load voltage Vo of the load R in the main circuit and sends it into the load detection circuit; A second input terminal of the load prediction circuit is connected with a reference voltage V ref An output terminal of the load prediction circuit is connected with a first input terminal of the main control circuit. The second input end of the main control circuit is connected with the output end of the current detection circuit, the third input end of the main control circuit is connected with the duty cycle reference value dref, the first output end of the main control circuit is connected with the first input end of the driving circuit, and the second output end of the main control circuit is connected with the second input end of the driving circuit; The input end of the current detection circuit is connected with the direct current power supply Vin in the main circuit by electricity; The first output end of the drive circuit is electrically connected with the gate of the first switch S1 in the main circuit, the second output end of the drive circuit is electrically connected with the gate of the second switch S2 in the main circuit, the drive circuit outputs control signals PWM1 and PWM2 and sends the control signals to the first switch S1 and the second switch S2 in the main circuit respectively, the main circuit controls the on-off of the first switch S1 and the second switch S2 through the output control signals PWM1 and PWM2 so that the output voltage of the main circuit is stabilized to the reference voltage V ref .

2. The high-gain transformation circuit of claim 1, wherein: The main circuit comprises a direct current power supply Vin, a first inductor L1, a second inductor L2, a third inductor L3, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6 and a seventh diode D7; The positive pole of the direct current power supply Vin is connected with the first end of the first inductor L1, the positive pole of the first diode D1, the first end of the third inductor L3 and the positive pole of the seventh diode D7 by electricity; The second end of the second inductor L1 is connected with the positive pole of the second diode D2 and the positive pole of the third diode D3 by electricity; The negative pole of the first diode D1 is connected with the positive pole of the second diode D2 and the first end of the second inductor L2 by electricity; The negative pole of the third diode D3 is connected with the second end of the second inductor L2, the first end of the second capacitor C2, the positive pole of the fourth diode D4 and the drain of the first switch tube S1 by electricity; The negative pole of the fourth diode D4 is connected with the first end of the first capacitor C1 and the positive pole of the fifth diode D5 by electricity; The negative pole of the fifth diode D5 is connected with the second end of the second capacitor C2 and the positive pole of the sixth diode D6 by electricity; The negative pole of the sixth diode D6 is connected with the first end of the third capacitor C3 and the first end of the load R.

3. The high-gain transformation circuit of claim 2, wherein: The main circuit further includes a fourth inductor L4, a fifth inductor L5, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, an eighth diode D8, a ninth diode D9, a twelfth diode D 10 , an eleventh diode D 11 , a tenth diode D 12 ; The second end of the third inductor L3 is connected with the positive pole of the eighth diode D8 and the first end of the fourth capacitor C4; The negative pole of the seventh diode D7 is connected with the second end of the fourth capacitor C4 and the first end of the fourth inductor L4 by electricity; The negative electrode of the eighth diode D8 is electrically connected with the second end of the fourth inductor L4, the first end positive electrode of the ninth diode D9 and the first end positive electrode of the twelfth diode D 10 ​ The negative pole of the ninth diode D9 is connected with the first end of the fifth capacitor C5 and the first end of the fifth inductor L5 by electricity; The twelfth diode D 10 The negative electrode of the twelfth diode D 11 is electrically connected with the second end of the fifth inductor L5, the drain of the second switch tube S2 and the positive electrode of the eleventh diode D The second end of the sixth capacitor C6 is electrically connected with the positive electrode of the tenth diode D 12 and the second end of the load R. The negative pole of the direct current power supply Vin is electrically connected with the source electrode of the first switch tube S1, the second end of the first capacitor C1, the second end of the third capacitor C3, the second end of the eleventh diode D 11 , the first end of the sixth capacitor C6, the second end of the fifth capacitor C5, the source electrode of the second switch tube S2 and the negative pole of the tenth diode D 12 .

4. The high-gain transformation circuit as claimed in claim 1, characterized in that: The control signals PWM1 and PWM2 output by the driving circuit have two modes, mode 1 and mode 2, wherein in the mode 1, the control signals PWM1 and PWM2 are in the high level state of Vgs1 and Vgs2, the first switch S1 and the second switch S2 are both turned on, the DC power Vin charges the first inductor L1, the second inductor L2, the third inductor L3, the fourth inductor L4 and the fourth capacitor C4, the first capacitor C1 charges the second capacitor C2, the fifth capacitor C5 charges the fifth inductor L5, and the third capacitor C3 and the sixth capacitor C6 charge the load R; in the mode 2, the control signals PWM1 and PWM2 are in the low level state of Vgs1 and Vgs2, the first switch S1 and the second switch S2 are both turned off, the DC power Vin, the first inductor L1 and the second inductor L2 charge the first capacitor C1, the DC power Vin, the third inductor L3, the fourth inductor L4 and the fourth capacitor C4 charge the fifth capacitor C5, the DC power Vin, the third inductor L3, the fourth inductor L4, the fifth inductor L5 and the fourth capacitor C4 charge the sixth capacitor C6 and the load R, and the DC power Vin, the first inductor L1, the second inductor L2 and the second capacitor C2 charge the third capacitor C3 and the load R.

5. The high-gain conversion circuit of claim 4, wherein: In the mode 1 and the mode 2, L1=L2, L3=L4, d1=d2, L1 is the inductance value of the first inductor L1, L2 is the inductance value of the second inductor L2, L3 is the inductance value of the third inductor L3, L4 is the inductance value of the fourth inductor L4, d1 is the duty ratio of PWM1, and d2 is the duty ratio of PWM2, the calculated inductance voltage value in the two modes is: And has: V C4 = V in V o = V C3 + V C6 According to the volt-second balance theorem of the inductor and the above formula, the voltage gain G is: Voltage gain 6. A control method of a high-gain conversion circuit, characterized by: The control method comprises the following steps: Step 1) The voltage detection circuit detects the voltage V of the main circuit load o and sends it into the load detection circuit, the current detection circuit detects the input current I of the main circuit in and sends it into the main control circuit; Step 2) The load detection circuit calculates the load prediction value I o based on the load voltage V ref and the reference voltage V p and sends it to the main control circuit. Step 3) The main control circuit performs operation dl = D p , input current I in and duty ratio reference value D ref , and sends them into the drive circuit, where K1 and K2 are control coefficients. ref -I in ) and d2 = D p -K2(I ref -I in ), and sends them into the drive circuit. p ​ Step 4) the driving circuit generates the control signals PWM1 and PWM2 according to d1 and d2, and sends PWM1 to the gate of the first switch S1 in the main circuit and sends PWM2 to the gate of the second switch S2 in the main circuit. Step 5) The first switch S1 and the second switch S2 are controlled according to the control signals PWM1 and PWM2 to make the output voltage stable to the reference voltage V ref .

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