Wide-range input and multi-path output power supply circuit

Abstract

The invention discloses a wide-range input and multi-path output power supply circuit, and in the power supply circuit, the input end of a rectifier bridge circuit is connected to the output end of an alternating current generator; the input end of the first-stage + 28V conversion circuit is connected to the output end of the rectifier bridge circuit; the input end of the second-stage + 15V / -15V conversion circuit is connected to the output end of the first-stage + 28V conversion circuit; wherein the input voltage and the + 28V output voltage of the second-stage + 15V / -15V conversion circuit are respectively connected to the output end of the first-stage + 28V conversion circuit through a diode common anode, so that one-way flow of current is ensured; the power supply circuit is used for rectifying the wide-range alternating-current voltage output by the alternating-current generator through the rectifier bridge circuit to form a wide-range direct-current voltage; a wide-range direct-current voltage output by the rectifier bridge circuit is converted into a + 28V voltage through the first-stage + 28V conversion circuit, the output + 28V voltage is directly used for supplying power to airborne electric equipment, and after the output + 28V voltage is processed by the second-stage + 15V / -15V conversion circuit, a + 15V output voltage Vo1 and a-15V output voltage Vo2 are formed. According to the technical scheme, the problem that a power supply circuit in an existing airborne power generation system cannot work normally under the condition of wide output voltage of a generator due to the fact that the power supply circuit is limited by the pulse width modulation range of a switching tube is solved.

Description

Technical Field

[0001] The present invention relates to the field of aviation power supply technology, but is not limited to it, and in particular to a power supply circuit with wide-range input and multi-channel output. Background Art

[0002] In current aviation variable frequency AC power generation systems, the generator is usually driven directly by the engine, and the generator output voltage is directly related to the engine output speed. Only when the engine output speed meets the requirements, that is, the generator output voltage reaches the rated voltage, can the onboard power generation system work normally and generate a voltage level suitable for the power demand of the onboard power equipment.

[0003] The airborne power generation system needs to be able to work normally when the engine speed is within a certain range. However, the wide engine speed range brings a wide output voltage range of the generator, which puts high demands on the power circuit design of the airborne power generation system. In addition, due to the different characteristics of different generator bodies, the output voltage range of the generator at the same speed also varies greatly. The design of the power circuit for the wide output voltage range of the above generator is particularly difficult, that is, it is particularly difficult to design a power circuit that can be applied to a wide output voltage range of multiple generators.

[0004] The power supply circuit solution in the existing airborne power generation system can ensure the normal operation of the generator within a certain speed range and output +28V, +15V, and -15V DC voltages to power the airborne electrical equipment. However, based on the existing circuit topology, when the ratio of the generator output maximum voltage to the minimum voltage reaches 3 times or even higher, the power supply circuit cannot work normally due to the limitation of the pulse width modulation range of the switching tube. Summary of the invention

[0005] Purpose of the present invention: In order to solve the above technical problems, an embodiment of the present invention provides a power supply circuit with wide input range and multiple outputs, so as to solve the problem that the power supply circuit in the existing airborne power generation system cannot work normally under the condition of wide output voltage of the generator due to being limited by the pulse width modulation range of the switching tube.

[0006] Technical solution of the present invention: The embodiment of the present invention provides a power supply circuit with wide-range input and multiple outputs, comprising: an AC generator 1, a rectifier bridge circuit 2, a first-stage +28V conversion circuit 3, and a second-stage +15V / -15V conversion circuit 4;

[0007] The input end of the rectifier bridge circuit 2 is connected to the output end of the AC generator 1; the input end of the first-stage +28V conversion circuit 3 is connected to the output end of the rectifier bridge circuit 2; the input end of the second-stage +15V / -15V conversion circuit 4 is connected to the output end of the first-stage +28V conversion circuit 3; the input and +28V output voltage of the second-stage +15V / -15V conversion circuit 4 are respectively connected to the output end of the first-stage +28V conversion circuit 3 through a diode common anode, thereby ensuring unidirectional flow of current;

[0008] The power supply circuit is used to rectify the wide-range AC voltage output by the AC generator 1 to form a wide-range DC voltage through the rectifier bridge circuit 2; the wide-range DC voltage output by the rectifier bridge circuit 2 is converted into a +28V voltage through the first-stage +28V conversion circuit 3, and the output +28V voltage is directly used to power the onboard electrical equipment. The output +28V voltage is processed by the second-stage +15V / -15V conversion circuit 4 to form a +15V output voltage V o1 With -15V output voltage V o2 .

[0009] Optionally, in the wide-range input multi-output power supply circuit as described above, the first-stage +28V conversion circuit 3 includes: a first power circuit, a sampling circuit 7, a driving circuit 10 and a control circuit 11;

[0010] The sampling circuit 7 includes a first sampling subcircuit 5 and a second sampling subcircuit 6, the input ends of the two sampling subcircuits are connected to the designated position points of the first power circuit, and are used to collect the input voltage and the flying capacitor voltage through the first sampling subcircuit 5, and collect the inductor current and the output voltage through the second sampling subcircuit 6; the output ends of the two sampling subcircuits are respectively connected to the input ends of the control circuit 11, the output end of the control circuit 11 is connected to the input end of the drive circuit 10, and the output end of the drive circuit 10 is respectively connected to the control end of the switch tube in the first power circuit;

[0011] The first-stage +28V conversion circuit 3 is used to collect the input voltage, flying capacitor voltage, inductor current and output voltage in the first power circuit through the sampling circuit 7 when the first power circuit is working normally, so that the control circuit 11 can implement voltage control on the first power circuit based on the collected quantities; wherein, the voltage control method of the first power circuit is: the control circuit 11 outputs the voltage control quantity to the drive circuit 10, so that the drive circuit 10 provides a switch signal quantity for controlling the working state of the switch tube of the first power circuit, thereby adjusting the flying capacitor voltage and the output voltage of the first power circuit to specified values.

[0012] Optionally, in the wide-range input multi-output power supply circuit as described above,

[0013] The first power circuit is configured as a three-level buck power circuit formed by a switch tube Q1, a switch tube Q2, a freewheeling diode D3, a freewheeling diode D4, a flying capacitor C1, a filter inductor L1, and a filter capacitor C2;

[0014] Among them, the drain of the switch tube Q1 and the output voltage V of the rectifier bridge circuit 2 in The positive electrode of the switch tube Q1 is connected; the source of the switch tube Q1 is connected to the drain of the switch tube Q2 and one end of the flying capacitor C1 respectively; the source of the switch tube Q2 is connected to the cathode of the diode D3 and one end of the filter inductor L1 respectively; the other end of the filter inductor L1 is connected to one end of the filter capacitor C2, and the other end of the filter inductor L1 is used as the +28V output V o The other end of the filter capacitor C2 and the anode of the diode D4 are connected to the negative electrode of the output voltage Vin of the rectifier bridge circuit 2, and are connected to the +28V output V o The other end of the flying capacitor C1 is connected to the anode of the diode D3 and the cathode of the diode D4 respectively.

[0015] Optionally, in the wide-range input multi-output power supply circuit as described above, the first power circuit has four operating modes in one switching cycle, which are:

[0016] Working mode 1: When the switch tube Q1 is turned on and the switch tube Q2 is not turned on, the output voltage V in Through the switch tube Q1, flying capacitor C1, freewheeling diode D3, filter inductor L1 to +28V output V o , the current flowing through the filter inductor L1 increases linearly;

[0017] Working mode 2: When both switch tubes Q1 and Q2 are turned off, the +28V output V o The freewheeling diode D4, freewheeling diode D3 and filter inductor L1 complete the freewheeling current;

[0018] Working mode three: When the switch tube Q1 is turned off and the switch tube Q2 is turned on, the flying capacitor C1 discharges, and the current flows through the freewheeling diode D4, the flying capacitor C1, the switch tube Q2, and the filter inductor L1 to the +28V output V o ;

[0019] Working mode 4: When both switch tube Q1 and switch tube Q2 are turned off, it is the same as working mode 2.

[0020] Optionally, in the wide-range input multi-output power supply circuit as described above,

[0021] The control circuit 11 includes: a voltage and current control loop and a flying capacitor voltage control loop connected in parallel, a logic operation circuit 8 and a PWM generation circuit 9; wherein the output ends of the two control loops are respectively connected to the input ends of the logic operation circuit 8, the output end of the logic operation circuit 8 is connected to the input end of the PWM generation circuit 9, and the output end of the PWM generation circuit 9 is connected to the input end of the drive circuit 10;

[0022] Among them, the input voltage signal line and the flying capacitor voltage signal line collected by the first sampling sub-circuit 5 are respectively connected to the input end of the flying capacitor voltage control loop, which is used to realize the closed-loop control of the flying capacitor voltage control loop, so as to realize that the flying capacitor voltage follows the half value of the input voltage; the inductor current signal line and the output voltage signal line collected by the second sampling sub-circuit 6 are respectively connected to the current input end and the voltage input end of the voltage-current control loop, which is used to realize that the output voltage follows the reference voltage value of the voltage-current control loop.

[0023] Optionally, in the wide-range input multi-output power supply circuit as described above,

[0024] Based on the input of the second sampling sub-circuit 6, the control circuit 11 collects the output voltage V o With reference value V ref The difference between the two is calculated by PI to obtain the reference value i for the current inner loop control. ref , the sampled inductor current i L with i ref The difference is calculated by PI operation to obtain the output of the voltage and current control loop, and the output is sent to the logic operation circuit 8;

[0025] Based on the input quantity of the first sampling sub-circuit 5, the control circuit 11 samples the input voltage V in / 2 and the voltage V across the flying capacitor C1 C1 The difference is calculated by PI operation to obtain the output of the flying capacitor voltage control loop, and the output is sent to the logic operation circuit 8 for processing;

[0026] The logic operation circuit 8 performs a logic superposition operation according to the output of the voltage and current control loop and the flying capacitor voltage control loop, and the output voltage signal is sent to the PWM generation circuit 9 to generate a PWM wave signal; the generated PWM wave signal is generated by the drive circuit 10 to generate a control signal for driving the switch tube Q1 and the switch tube Q2, thereby obtaining a stable +28V DC output voltage.

[0027] Optionally, in the wide-range input multi-output power supply circuit as described above, the second-stage +15V / -15V conversion circuit 4 includes: a second power circuit, a compensation circuit 12 and a flyback circuit control chip 13;

[0028] Among them, the input end of the second power circuit is connected to the output end of the first-stage +28V conversion circuit 3, and its +15V output end is connected to the input end of the compensation circuit 12, and the output end of the compensation circuit 12 is connected to the input end of the flyback circuit control chip 13, so that the flyback circuit control chip 13 generates a pulse width modulation signal for controlling the on and off of the switch tube Q3 according to the received input control amount.

[0029] Optionally, in the wide-range input multi-output power supply circuit as described above, the second power circuit is configured as: a single-tube flyback power circuit formed by a switch tube Q3, a diode D5, a diode D6, a diode D7, a filter capacitor C3, a filter capacitor C4, a filter capacitor C5, a transformer T1, and a sampling resistor R1;

[0030] Among them, the same-name terminal of the primary side of transformer T1 is connected to the first-stage +28V output voltage V o The positive electrode of the transformer T1 is connected, the opposite end of the primary side is connected to the drain of the switch tube Q3, the source of the switch tube Q3 is connected to one end of the sampling resistor R1, and the other end of the sampling resistor R1 is connected to the +28V output voltage V o The negative pole is connected;

[0031] The opposite end of the first secondary winding of transformer T1 is connected to the anode of diode D5, and the cathode of diode D5 is connected to the +15V output voltage V o1 The positive terminal of the first secondary winding of transformer T1 is connected to the +15V output voltage V o1 The ground is connected to the ground, and a filter capacitor C3 is connected between the same-name end of the first secondary winding of the transformer T1 and the cathode of the diode D5;

[0032] The opposite end of the second secondary winding of transformer T1 is connected to the anode of diode D6, and the cathode of diode D6 is connected to the +15V output voltage V o1 The second secondary winding of transformer T1 is connected to the -15V output voltage V o2 , and a filter capacitor C4 is connected between the same-name end of the second secondary winding of the transformer T1 and the cathode of the diode D6;

[0033] The third secondary winding of transformer T1 is connected to the anode of diode D7, and the cathode of diode D7 is connected to the +15V flyback circuit control chip supply voltage V o4 The positive pole of the transformer T1 third secondary winding is connected to the +15V flyback circuit control chip power supply V o4 A filter capacitor C5 is connected between the negative electrode of the third secondary winding of the transformer T1 and the cathode of the diode D7.

[0034] Optionally, in the wide-range input multi-output power supply circuit as described above,

[0035] The second power circuit outputs a +15V output voltage V o1 With reference value V ref2 The difference is input to the flyback circuit control chip 13 through the compensation circuit 12 as the input control quantity of the flyback circuit control chip 13; the +15V flyback circuit supply voltage V output by the second power circuit o4 As the power supply voltage of the flyback circuit control chip 13; by collecting the current i flowing through the sampling resistor R1 in the second power circuit L2 , and the collected current i L2 Transmitted to the flyback circuit control chip 13 to implement overcurrent protection for the second power circuit;

[0036] The flyback circuit control chip 13 generates a PWM wave signal for driving Q3 according to the input control amount transmitted by the compensation circuit 12, thereby realizing closed-loop control of the second power circuit and obtaining a stable +15V, -15V DC output voltage.

[0037] Beneficial effects of the present invention: A power supply circuit with wide-range input and multiple outputs provided by an embodiment of the present invention rectifies a wide-range AC voltage output by an AC generator 1 into a wide-range DC voltage through a rectifier bridge circuit 2; converts the wide-range DC voltage output by the rectifier bridge circuit 2 into a +28V voltage through a first-stage +28V conversion circuit 3, and the output +28V voltage is directly used to power airborne electrical equipment. The output +28V voltage is processed by a second-stage +15V / -15V conversion circuit 4 to form a +15V output voltage V o1 With -15V output voltage V o2 The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[0038] First, the power supply circuit provided by the embodiment of the present invention can be applied to different types of generators and supports a wide range of 40V-150V AC voltage input, thus solving the problem of narrow operating voltage of the power supply circuit of the traditional power generation system;

[0039] Second, the power supply circuit provided in the embodiment of the present invention can provide +28V, +15V, -15V DC output to meet the power requirements of airborne equipment at different voltage levels;

[0040] Third, based on the first-stage +28V conversion circuit 3 set in the power supply circuit of the present invention, it can ensure that the voltage stress of the switch tube Q1, the switch tube Q2 and the flying capacitor C1 is maintained at half of the input voltage. Compared with the traditional step-down circuit, it greatly reduces the difficulty of selecting circuit components and improves the reliability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0042] Figure 1 A schematic diagram of the circuit structure of a power supply circuit with wide input range and multiple outputs provided by an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of the circuit structure of the first-stage +28V conversion circuit in the wide-range input multi-output power supply circuit provided by an embodiment of the present invention;

[0044] Figure 3 for Figure 2 Schematic diagram of four operating modes of the first power circuit in the first-stage +28V conversion circuit provided by the illustrated embodiment; Figure 3 Figure a is working mode 1, Figure b is working mode 2, Figure c is working mode 3, and Figure d is working mode 4;

[0045] Figure 4 A schematic diagram of the circuit structure of a second-stage +15V / -15V conversion circuit in a wide-range input multi-output power supply circuit provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present invention more clear, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other arbitrarily without conflict.

[0047] As explained in the above background technology, it is particularly difficult to design a power supply circuit that can be applied to a wide output voltage range of multiple generators. In the existing power supply circuit of the airborne power generation system, when the ratio of the highest voltage to the lowest voltage of the generator output reaches 3 times or even higher, the power supply circuit cannot work normally due to the limitation of the pulse width modulation range of the switch tube. Therefore, it is very meaningful to design a power supply circuit that can work in a wide voltage range.

[0048] In order to solve the above problems, an embodiment of the present invention provides a power supply circuit with wide-range input and multi-output. The power supply circuit supports 40V-150V AC input (that is, the wide output voltage range of the generator), +28V, +15V, and -15V DC outputs, and can be applied to a variety of generators. It solves the power supply adaptability problem with a wide input voltage range and provides an efficient and reliable solution.

[0049] The present invention provides the following specific embodiments which can be combined with each other. The same or similar concepts or processes may not be described in detail in some embodiments.

[0050] Figure 1 The circuit structure diagram of a power supply circuit with wide input range and multiple outputs provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the main structure of the power supply circuit with wide-range input and multi-output provided by the embodiment of the present invention includes: an AC generator 1, a rectifier bridge circuit 2, a first-stage +28V conversion circuit 3, and a second-stage +15V / -15V conversion circuit 4.

[0051] like Figure 1 In the circuit structure shown, the input end of the rectifier bridge circuit 2 is connected to the output end of the AC generator 1; the input end of the first-stage +28V conversion circuit 3 is connected to the output end of the rectifier bridge circuit 2; the input end of the second-stage +15V / -15V conversion circuit 4 is connected to the output end of the first-stage +28V conversion circuit 3. It should be noted that the input and +28V output voltage of the second-stage +15V / -15V conversion circuit 4 are respectively connected to the output end of the first-stage +28V conversion circuit 3 through a diode common anode, thereby ensuring unidirectional flow of current.

[0052] In the power supply circuit provided by the embodiment of the present invention, the working principles of the above-mentioned parts are as follows:

[0053] The rectifier bridge circuit 2 is used to rectify the wide-range AC voltage output by the AC generator 1 into a wide-range DC voltage.

[0054] The first-stage +28V conversion circuit 3 is used to convert the wide-range DC voltage output by the rectifier bridge circuit 2 into a +28V voltage. The +28V voltage output by the first-stage +28V conversion circuit 3 is directly used to power the onboard electrical equipment;

[0055] The second stage +15V / -15V conversion circuit 4 is used to convert the +28V voltage output by the first stage +28V conversion circuit 3 to form a +15V output voltage V o1 With -15V output voltage V o2 .

[0056] In one implementation of the embodiment of the present invention, there is provided Figure 1 A circuit form of the first stage +28V conversion circuit 3, such as Figure 2 FIG. 1 is a schematic diagram of the circuit structure of the first-stage +28V conversion circuit in the wide-range input multi-output power supply circuit provided by an embodiment of the present invention. The first-stage +28V conversion circuit 3 in this implementation includes: a first power circuit, a sampling circuit 7, a driving circuit 10 and a control circuit 11.

[0057] In this implementation, the sampling circuit 7 includes a first sampling subcircuit 5 and a second sampling subcircuit 6, the input ends of the two sampling subcircuits are connected to the specified position points of the first power circuit, and are used to collect the input voltage and the flying capacitor voltage through the first sampling subcircuit 5, and collect the inductor current and the output voltage through the second sampling subcircuit 6; the output ends of the two sampling subcircuits are respectively connected to the input ends of the control circuit 11, the output end of the control circuit 11 is connected to the input end of the drive circuit 10, and the output ends of the drive circuit 10 are respectively connected to the control ends of the switch tubes in the first power circuit.

[0058] The first-stage +28V conversion circuit 3 in this implementation is used to collect the input voltage, flying capacitor voltage, inductor current and output voltage in the first power circuit through the sampling circuit 7 when the first power circuit is working normally, so that the control circuit 11 can implement voltage control on the first power circuit based on the collected amount. It should be noted that in this implementation, the voltage control method of the first power circuit is: the control circuit 11 outputs the voltage control amount to the drive circuit 10, so that the drive circuit 10 provides a switch signal amount for controlling the working state of the switch tube of the first power circuit, thereby adjusting the flying capacitor voltage and the output voltage of the first power circuit to the specified value.

[0059] In this implementation, for the wide range DC voltage output by the rectifier bridge circuit 2, the first-stage +28V conversion circuit 3 obtains the changing sampling input value through the sampling circuit 7, obtains the changing voltage control amount through the control circuit 11, and the changing voltage control amount obtains the first power circuit switch tube control signal with a changing duty cycle through the driving circuit 10, thereby adjusting the flying capacitor voltage and the output voltage of the first power circuit to the specified value.

[0060] In one implementation of the embodiment of the present invention, Figure 2 As shown, the first power circuit is configured as a three-level buck power circuit formed by a switch tube Q1, a switch tube Q2, a freewheeling diode D3, a freewheeling diode D4, a flying capacitor C1, a filter inductor L1, and a filter capacitor C2.

[0061] In this implementation, the drain of the switch tube Q1 and the output voltage V of the rectifier bridge circuit 2 are connected. in The positive electrode of the switch tube Q1 is connected; the source of the switch tube Q1 is connected to the drain of the switch tube Q2 and one end of the flying capacitor C1 respectively; the source of the switch tube Q2 is connected to the cathode of the diode D3 and one end of the filter inductor L1 respectively; the other end of the filter inductor L1 is connected to one end of the filter capacitor C2, and the other end of the filter inductor L1 is used as the +28V output V o The other end of the filter capacitor C2 and the anode of the diode D4 are connected to the negative electrode of the output voltage Vin of the rectifier bridge circuit 2, and are connected to the +28V output V oThe other end of the flying capacitor C1 is connected to the anode of the diode D3 and the cathode of the diode D4 respectively.

[0062] The working principle of the first power circuit is described as follows:

[0063] The first power circuit has four operating modes in one switching cycle, such as Figure 3 As shown, Figure 2 The illustrated embodiment provides a schematic diagram of four operating modes of the first power circuit in the first-stage +28V conversion circuit. Figure 3 Figure a is working mode one, figure b is working mode two, figure c is working mode three, and figure d is working mode four.

[0064] like Figure 3 The working mode of the first power circuit shown in Figure a is as follows: when the switch tube Q1 is turned on and the switch tube Q2 is not turned on, the output voltage V in Through the switch tube Q1, flying capacitor C1, freewheeling diode D3, filter inductor L1 to +28V output V o , the current flowing through the filter inductor L1 increases linearly.

[0065] like Figure 3 The second working mode of the first power circuit is shown in Figure b. When both switch tubes Q1 and Q2 are turned off, the +28V output V o The freewheeling diode D4, the freewheeling diode D3 and the filter inductor L1 complete the freewheeling.

[0066] like Figure 3 Figure c shows the working mode 3 of the first power circuit. When the switch tube Q1 is turned off and the switch tube Q2 is turned on, the flying capacitor C1 discharges, and the current flows through the freewheeling diode D4, the flying capacitor C1, the switch tube Q2, and the filter inductor L1 to the +28V output V o .

[0067] like Figure 3 The working mode 4 of the first power circuit shown in Figure d in FIG. 1 is the same as the working mode 2 of the first power circuit shown in Figure b, and will not be repeated here.

[0068] In one implementation of the embodiment of the present invention, Figure 2 As shown, the control circuit 11 includes: a voltage and current control loop and a flying capacitor voltage control loop in parallel, a logic operation circuit 8 and a PWM generation circuit 9; wherein the output ends of the two control loops are respectively connected to the input ends of the logic operation circuit 8, the output end of the logic operation circuit 8 is connected to the input end of the PWM generation circuit 9, and the output end of the PWM generation circuit 9 is connected to the input end of the drive circuit 10.

[0069] In this implementation, the input voltage signal line and the flying capacitor voltage signal line collected by the first sampling subcircuit 5 are respectively connected to the input end of the flying capacitor voltage control loop, so as to realize the closed-loop control of the flying capacitor voltage control loop, so as to realize the flying capacitor voltage following the half value of the input voltage; the inductor current signal line and the output voltage signal line collected by the second sampling subcircuit 6 are respectively connected to the current input end and the voltage input end of the voltage-current control loop, so as to realize the output voltage following the reference voltage value of the voltage-current control loop.

[0070] Based on the circuit structure relationship between the two sampling sub-circuits and the first power circuit and the control circuit 11 in this implementation, the following control effects can be achieved:

[0071] On the one hand, based on the input of the second sampling sub-circuit 6, the control circuit 11 collects the output voltage V o With reference value V ref The difference between the two is calculated by PI to obtain the reference value i for the current inner loop control. ref , the sampled inductor current i L with i ref The difference is calculated by PI operation to obtain the output of the voltage and current control loop, and the output is sent to the logic operation circuit 8;

[0072] On the other hand, based on the input quantity of the first sampling sub-circuit 5, the control circuit 11 converts the sampled input voltage V in / 2 and the voltage V across the flying capacitor C1 C1 The difference is processed by PI operation to obtain the output of the flying capacitor voltage control loop, and the output is sent to the logic operation circuit 8 for processing.

[0073] On this basis, the logic operation circuit 8 in this implementation performs a logic superposition operation according to the output of the voltage and current control loop and the flying capacitor voltage control loop, and the output voltage signal is sent to the PWM generation circuit 9 to generate a PWM wave signal; the generated PWM wave signal is generated by the drive circuit 10 to generate a control signal for driving the switch tube Q1 and the switch tube Q2, thereby obtaining a stable +28V DC output voltage.

[0074] It should be noted that the principle by which the first-stage +28V conversion circuit 3 in this implementation can obtain a stable +28V DC output voltage is as follows:

[0075] When the load disturbance causes the +28V output V o When the output voltage V o With reference value V ref The difference increases, and the changing current inner loop control reference i is obtained through PI operation. ref , the changing current inner loop control reference i refThe inductor current i collected by the second sampling sub-circuit 6 L The difference increases at the same time, and the increased voltage and current control loop output is obtained through PI operation. The increased duty cycle control amount of the switch tube Q1 and the switch tube Q2 is obtained through the logic operation circuit 8 and the PWM generation circuit 9. The +28V output voltage V o Increased, achieving the stability of the +28V DC output voltage.

[0076] In one implementation of the embodiment of the present invention, an implementation structure of the second-stage +15V / -15V conversion circuit 4 is provided, such as Figure 4 As shown, it is a circuit structure diagram of the second-stage +15V / -15V conversion circuit in the wide-range input multi-output power supply circuit provided by an embodiment of the present invention. The second-stage +15V / -15V conversion circuit 4 in this implementation includes: a second power circuit, a compensation circuit 12 and a flyback circuit control chip 13.

[0077] In this implementation, the input end of the second power circuit is connected to the output end of the first-stage +28V conversion circuit 3, and its +15V output end is connected to the input end of the compensation circuit 12. The output end of the compensation circuit 12 is connected to the input end of the flyback circuit control chip 13, so that the flyback circuit control chip 13 generates a pulse width modulation signal for controlling the on and off of the switch tube Q3 according to the received input control amount.

[0078] In one implementation of this implementation, the second power circuit is configured as: a single-tube flyback power circuit formed by a switch tube Q3, a diode D5, a diode D6, a diode D7, a filter capacitor C3, a filter capacitor C4, a filter capacitor C5, a transformer T1, and a sampling resistor R1.

[0079] like Figure 4 As shown, the same-name terminal of the primary side of transformer T1 is connected to the first-stage +28V output voltage V o The positive electrode of the transformer T1 is connected, the opposite end of the primary side is connected to the drain of the switch tube Q3, the source of the switch tube Q3 is connected to one end of the sampling resistor R1, and the other end of the sampling resistor R1 is connected to the +28V output voltage V o The negative pole is connected;

[0080] The opposite end of the first secondary winding of transformer T1 is connected to the anode of diode D5, and the cathode of diode D5 is connected to the +15V output voltage V o1 The positive terminal of the first secondary winding of transformer T1 is connected to the +15V output voltage V o1 The ground is connected to the ground, and a filter capacitor C3 is connected between the same-name end of the first secondary winding of the transformer T1 and the cathode of the diode D5;

[0081] The opposite end of the second secondary winding of transformer T1 is connected to the anode of diode D6, and the cathode of diode D6 is connected to the +15V output voltage V o1 The second secondary winding of transformer T1 is connected to the -15V output voltage V o2 , and a filter capacitor C4 is connected between the same-name end of the second secondary winding of the transformer T1 and the cathode of the diode D6;

[0082] The third secondary winding of transformer T1 is connected to the anode of diode D7, and the cathode of diode D7 is connected to the +15V flyback circuit control chip supply voltage V o4 The positive pole of the transformer T1 third secondary winding is connected to the +15V flyback circuit control chip power supply V o4 A filter capacitor C5 is connected between the negative electrode of the third secondary winding of the transformer T1 and the cathode of the diode D7.

[0083] In this implementation, the working principle of the second power circuit is:

[0084] When the switch tube Q3 of the second power circuit is turned on, the first stage +28V output voltage V o The output is sent to transformer T1, which stores energy. At this time, the secondary winding of transformer T1 is not conducting. When the switch tube Q3 of the second power circuit is turned off, transformer T1 releases energy to the secondary winding of the transformer, and the +15V output voltage V is collected. o1 The compensation circuit 12 and the flyback circuit control chip 13 generate a pulse width modulation signal for controlling the duty cycle change of the switch tube Q3, thereby realizing the control of the +15V and -15V DC output voltages.

[0085] Furthermore, the +15V output voltage V output by the second power circuit o1 With reference value V ref2 The difference is input to the flyback circuit control chip 13 through the compensation circuit 12 as the input control quantity of the flyback circuit control chip 13; the +15V flyback circuit supply voltage V output by the second power circuit o4 As the power supply voltage of the flyback circuit control chip 13; by collecting the current i flowing through the sampling resistor R1 in the second power circuit L2 , and the collected current i L2 The signal is transmitted to the flyback circuit control chip 13 to implement overcurrent protection for the second power circuit.

[0086] The flyback circuit control chip 13 generates a PWM wave signal for driving Q3 according to the input control amount transmitted by the compensation circuit 12, thereby realizing closed-loop control of the second power circuit and obtaining a stable +15V, -15V DC output voltage.

[0087] It should be noted that the principle of the second-stage +15V / -15V conversion circuit 4 outputting stable +15V and -15V DC output voltages is as follows:

[0088] When the +15V output voltage V o1 When it increases, the change is related to V ref2 The reference value is subtracted and input to the flyback circuit control chip 13 through the compensation circuit 12; the flyback circuit control chip 13 generates a PWM wave signal with a reduced duty cycle switch tube Q3 to make the +15V output voltage V o1 Reduce to achieve +15V output voltage V o1 Closed-loop stability control.

[0089] The wide-range input multi-output power supply circuit provided in the embodiment of the present invention rectifies the wide-range AC voltage output by the AC generator 1 into a wide-range DC voltage through the rectifier bridge circuit 2; converts the wide-range DC voltage output by the rectifier bridge circuit 2 into a +28V voltage through the first-stage +28V conversion circuit 3, and the output +28V voltage is directly used to power the onboard electrical equipment. The output +28V voltage is processed by the second-stage +15V / -15V conversion circuit 4 to form a +15V output voltage V o1 With -15V output voltage V o2 The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[0090] First, the power supply circuit provided by the embodiment of the present invention can be applied to different types of generators and supports a wide range of 40V-150V AC voltage input, thus solving the problem of narrow operating voltage of the power supply circuit of the traditional power generation system;

[0091] Second, the power supply circuit provided in the embodiment of the present invention can provide +28V, +15V, -15V DC output to meet the power requirements of airborne equipment at different voltage levels;

[0092] Third, based on the first-stage +28V conversion circuit 3 set in the power supply circuit of the present invention, it can ensure that the voltage stress of the switch tube Q1, the switch tube Q2 and the flying capacitor C1 is maintained at half of the input voltage. Compared with the traditional step-down circuit, it greatly reduces the difficulty of selecting circuit components and improves the reliability of the circuit.

[0093] The implementation effect of the power supply circuit with wide input range and multiple outputs provided by the embodiment of the present invention is described as follows through an application example:

[0094] The present invention is applied to the following example schemes: Figure 1As shown, when the output voltage of the AC generator 1 is higher than 40V, the output voltage is rectified by the rectifier bridge circuit 2 and input to the first-stage +28V conversion circuit 3. The first-stage +28V conversion circuit 3 starts to work normally and generates a +28V output voltage to supply power to the onboard electrical equipment. At the same time, it also supplies power to the second-stage +15V / -15V conversion circuit 4, so that it can generate a +15V output voltage V o1 With -15V output voltage V o2 .

[0095] The first stage +28V conversion circuit 3 is as follows Figure 2 The main circuit topology of this circuit is a three-level buck circuit. Compared with the traditional buck circuit, the voltage stress at both ends of the switch tube of the three-level buck circuit under the same input voltage is only half of the input voltage, which greatly reduces the difficulty of selecting circuit components; the designed control circuit can realize the closed-loop control of the output voltage and the closed-loop control of the voltage at both ends of the flying capacitor C1; when the load changes or the input voltage changes, resulting in a +28V output V o When fluctuation occurs, the fluctuation amount is proportional to V ref The difference enters the PI loop for calculation and samples the current i flowing through the inductor. L Based on the dual-loop PI function, the output PWM wave size is adjusted through the logic operation circuit 8 and the PWM generation circuit 9 to maintain the +28V output voltage V o The voltage V across the flying capacitor C1 is stable. C1 The stability is also achieved through PI closed-loop control, which always ensures that the voltage across the flying capacitor C1 and the voltage across the switch tube Q1 and the switch tube Q2 are maintained at half of the input voltage.

[0096] The second stage +15V / -15V conversion circuit 4 is as follows Figure 4 As shown. The main topology of this circuit is a single-tube flyback circuit; when the +15V output voltage V o1 When fluctuation occurs, the fluctuation amount is proportional to V ref2 The reference value is compared and input to the flyback circuit control chip 13 via the compensation circuit 12. The flyback circuit control chip 13 is powered by +15V flyback circuit control chip V o4 Power supply. Sample the current i flowing through the sampling resistor R1 L2 The input is sent to the flyback circuit control chip 13 to realize overcurrent protection for the single-tube flyback main circuit. The flyback circuit control chip 13 generates a Q3 drive waveform 14 to realize closed-loop control of the second-stage +15V and -15V output voltages.

[0097] Although the embodiments disclosed in the present invention are as above, the contents are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A power supply circuit with wide input range and multiple outputs, characterized in that: include: An alternating current generator (1), a rectifier bridge circuit (2), a first-stage +28V conversion circuit (3), and a second-stage +15V / -15V conversion circuit (4); The input end of the rectifier bridge circuit (2) is connected to the output end of the AC generator (1); the input end of the first-stage +28V conversion circuit (3) is connected to the output end of the rectifier bridge circuit (2); the input end of the second-stage +15V / -15V conversion circuit (4) is connected to the output end of the first-stage +28V conversion circuit (3); the input and +28V output voltage of the second-stage +15V / -15V conversion circuit (4) are respectively connected to the output end of the first-stage +28V conversion circuit (3) through a diode common anode, thereby ensuring unidirectional flow of current; The power supply circuit is used to rectify the wide-range AC voltage output by the AC generator (1) to form a wide-range DC voltage through the rectifier bridge circuit (2); the wide-range DC voltage output by the rectifier bridge circuit (2) is converted into a +28V voltage through the first-stage +28V conversion circuit (3); the output +28V voltage is directly used to power the onboard electrical equipment; the output +28V voltage is processed by the second-stage +15V / -15V conversion circuit (4) to form a +15V output voltage V o1 With -15V output voltage V o2 .

2. The wide-range input multi-output power supply circuit according to claim 1, characterized in that: The first-stage +28V conversion circuit (3) comprises: a first power circuit, a sampling circuit (7), a driving circuit (10) and a control circuit (11); The sampling circuit (7) comprises a first sampling subcircuit (5) and a second sampling subcircuit (6); the input ends of the two sampling subcircuits are connected to a designated position point of the first power circuit, and are used to collect input voltage and flying capacitor voltage through the first sampling subcircuit (5), and collect inductor current and output voltage through the second sampling subcircuit (6); the output ends of the two sampling subcircuits are respectively connected to the input end of the control circuit (11), the output end of the control circuit (11) is connected to the input end of the drive circuit (10), and the output end of the drive circuit (10) is respectively connected to the control end of the switch tube in the first power circuit; The first-stage +28V conversion circuit (3) is used to collect input voltage, flying capacitor voltage, inductor current and output voltage in the first power circuit through a sampling circuit (7) when the first power circuit is operating normally, so that the control circuit (11) can implement voltage control on the first power circuit based on the collected values; wherein the voltage control on the first power circuit is performed in the following manner: the control circuit (11) outputs the voltage control value to the drive circuit (10), so that the drive circuit (10) provides a switch signal value for controlling the working state of the switch tube of the first power circuit, thereby adjusting the flying capacitor voltage and the output voltage of the first power circuit to specified values.

3. The wide-range input multi-output power supply circuit according to claim 2, characterized in that: The first power circuit is configured as a three-level buck power circuit formed by a switch tube Q1, a switch tube Q2, a freewheeling diode D3, a freewheeling diode D4, a flying capacitor C1, a filter inductor L1, and a filter capacitor C2; The drain of the switch tube Q1 and the output voltage V of the rectifier bridge circuit (2) are in The positive electrode of the switch tube Q1 is connected; the source of the switch tube Q1 is connected to the drain of the switch tube Q2 and one end of the flying capacitor C1 respectively; the source of the switch tube Q2 is connected to the cathode of the diode D3 and one end of the filter inductor L1 respectively; the other end of the filter inductor L1 is connected to one end of the filter capacitor C2, and the other end of the filter inductor L1 is used as the +28V output V o The other end of the filter capacitor C2 and the anode of the diode D4 are connected to the negative electrode of the output voltage Vin of the rectifier bridge circuit (2) and are connected to the +28V output V o The other end of the flying capacitor C1 is connected to the anode of the diode D3 and the cathode of the diode D4 respectively.

4. The wide-range input multi-output power supply circuit according to claim 3, characterized in that: The first power circuit has four operating modes in one switching cycle, namely: Working mode 1: When the switch tube Q1 is turned on and the switch tube Q2 is not turned on, the output voltage V in Through the switch tube Q1, flying capacitor C1, freewheeling diode D3, filter inductor L1 to +28V output V o , the current flowing through the filter inductor L1 increases linearly; Working mode 2: When both switch tubes Q1 and Q2 are turned off, the +28V output V o The freewheeling diode D4, freewheeling diode D3 and filter inductor L1 complete the freewheeling current; Working mode three: When the switch tube Q1 is turned off and the switch tube Q2 is turned on, the flying capacitor C1 discharges, and the current flows through the freewheeling diode D4, the flying capacitor C1, the switch tube Q2, and the filter inductor L1 to the +28V output V o ; Working mode 4: When both switch tube Q1 and switch tube Q2 are turned off, it is the same as working mode 2.

5. The power supply circuit with wide input range and multiple outputs according to claim 3, characterized in that: The control circuit (11) comprises: a voltage and current control loop and a flying capacitor voltage control loop connected in parallel, a logic operation circuit (8) and a PWM generation circuit (9); wherein the output ends of the two control loops are respectively connected to the input ends of the logic operation circuit (8), the output end of the logic operation circuit (8) is connected to the input end of the PWM generation circuit (9), and the output end of the PWM generation circuit (9) is connected to the input end of the drive circuit (10); The input voltage signal line and the flying capacitor voltage signal line collected by the first sampling subcircuit (5) are respectively connected to the input end of the flying capacitor voltage control loop, so as to realize the closed-loop control of the flying capacitor voltage control loop, so as to realize the flying capacitor voltage follows the half value of the input voltage; the inductor current signal line and the output voltage signal line collected by the second sampling subcircuit (6) are respectively connected to the current input end and the voltage input end of the voltage and current control loop, so as to realize the output voltage follows the reference voltage value of the voltage and current control loop.

6. The wide-range input multi-output power supply circuit according to claim 5, characterized in that: Based on the input quantity of the second sampling subcircuit (6), the control circuit (11) collects the output voltage V o With reference value V ref The difference is calculated by PI to obtain the reference value i for the current inner loop control. ref , the sampled inductor current i L with i ref The difference is calculated by PI operation to obtain the output of the voltage and current control loop, and the output is sent to the logic operation circuit (8); Based on the input quantity of the first sampling subcircuit (5), the control circuit (11) samples the input voltage V in / 2 and the voltage V across the flying capacitor C1 C1 The difference is processed by PI operation to obtain the output of the flying capacitor voltage control loop, and the output is sent to the logic operation circuit (8) for processing; The logic operation circuit (8) performs a logic superposition operation according to the outputs of the voltage and current control loop and the flying capacitor voltage control loop, and the output voltage signal is sent to the PWM generation circuit (9) to generate a PWM wave signal; the generated PWM wave signal is used to generate a control signal for driving the switch tube Q1 and the switch tube Q2 via the drive circuit (10), thereby obtaining a stable +28V DC output voltage.

7. The wide-range input multi-output power supply circuit according to any one of claims 1 to 6, characterized in that: The second-stage +15V / -15V conversion circuit (4) comprises: a second power circuit, a compensation circuit (12) and a flyback circuit control chip (13); The input end of the second power circuit is connected to the output end of the first-stage +28V conversion circuit (3), the +15V output end thereof is connected to the input end of the compensation circuit (12), and the output end of the compensation circuit (12) is connected to the input end of the flyback circuit control chip (13), so that the flyback circuit control chip (13) generates a pulse width modulation signal for controlling the on and off of the switch tube Q3 according to the received input control amount.

8. The wide-range input multi-output power supply circuit according to claim 7, characterized in that: The second power circuit is configured as a single-tube flyback power circuit formed by a switch tube Q3, a diode D5, a diode D6, a diode D7, a filter capacitor C3, a filter capacitor C4, a filter capacitor C5, a transformer T1, and a sampling resistor R1; Among them, the same-name terminal of the primary side of transformer T1 is connected to the first-stage +28V output voltage V o The positive electrode of the transformer T1 is connected, the opposite end of the primary side is connected to the drain of the switch tube Q3, the source of the switch tube Q3 is connected to one end of the sampling resistor R1, and the other end of the sampling resistor R1 is connected to the +28V output voltage V o The negative pole is connected; The opposite end of the first secondary winding of transformer T1 is connected to the anode of diode D5, and the cathode of diode D5 is connected to the +15V output voltage V o1 The positive terminal of the first secondary winding of transformer T1 is connected to the +15V output voltage V o1 The ground is connected to the ground, and a filter capacitor C3 is connected between the same-name end of the first secondary winding of the transformer T1 and the cathode of the diode D5; The opposite end of the second secondary winding of transformer T1 is connected to the anode of diode D6, and the cathode of diode D6 is connected to the +15V output voltage V o1 The second secondary winding of transformer T1 is connected to the -15V output voltage V o2 , and a filter capacitor C4 is connected between the same-name end of the second secondary winding of the transformer T1 and the cathode of the diode D6; The third secondary winding of transformer T1 is connected to the anode of diode D7, and the cathode of diode D7 is connected to the +15V flyback circuit control chip supply voltage V o4 The positive pole of the transformer T1 third secondary winding is connected to the +15V flyback circuit control chip power supply V o4 A filter capacitor C5 is connected between the negative electrode of the third secondary winding of the transformer T1 and the cathode of the diode D7.

9. The wide-range input multi-output power supply circuit according to claim 8, characterized in that: The second power circuit outputs a +15V output voltage V o1 With reference value V ref2 The difference is input to the flyback circuit control chip (13) through the compensation circuit (12) as the input control quantity of the flyback circuit control chip (13); the +15V flyback circuit supply voltage V output by the second power circuit o4 As the power supply voltage of the flyback circuit control chip (13); by collecting the current i flowing through the sampling resistor R1 in the second power circuit L2 , and the collected current i L2 Transmitted to the flyback circuit control chip (13) to implement overcurrent protection for the second power circuit; The flyback circuit control chip (13) generates a PWM wave signal for driving Q3 according to the input control quantity transmitted by the compensation circuit (12), thereby realizing closed-loop control of the second power circuit and obtaining stable +15V, -15V DC output voltages.

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