Direct-current switching power supply series circuit

Abstract

The invention discloses a direct-current switching power supply series circuit, which realizes direct-current conversion of input high voltage by connecting direct-current switching power supply modules in series, and realizes synchronous control of working states of a plurality of direct-current switching power supply modules through cooperation of a PWM (Pulse Width Modulation) controller, a synchronous driving controller and an output sampling loop. The circuit is suitable for the application scene of ultrahigh voltage input, and can be widely applied to the technical field of electronic circuits.

Description

Technical Field

[0001] This application relates to the technical field of electronic circuits, and particularly to a series circuit of DC switching power supplies. Background Art

[0002] A DC switching power supply is a power supply device that converts alternating current into stable direct current. It converts the input alternating current into the required DC voltage and current output through high-frequency switching control.

[0003] A DC switching power supply generally consists of a PWM controller and MOSFET or IGBT tubes. In the environment of new energy such as photovoltaic, the voltage input to the DC switching power supply may be as high as several hundred volts to several thousand volts of DC voltage. Once the input voltage is greater than the withstand voltage of the MOSFET or IGBT tubes, the DC switching power supply cannot achieve the DC conversion of the input high voltage. Summary of the Invention

[0004] The main purpose of the embodiments of this application is to propose a series circuit of DC switching power supplies, which can achieve the DC conversion of the input high voltage and improve the DC conversion efficiency.

[0005] The embodiments of this application propose a series circuit of DC switching power supplies, including: a PWM controller, a synchronous drive controller, an output sampling circuit, and multiple DC switching power supply modules; the DC switching power supply modules are connected in series with each other, and each DC switching power supply module includes an input end and an output end;

[0006] The input ends of the DC switching power supply modules are connected in parallel with a first resistor, a first capacitor, and a first diode;

[0007] Determine a first DC switching power supply module, multiple second DC switching power supply modules, and a third DC switching power supply module from the multiple DC switching power supply modules, where the first DC switching power supply module is the DC switching power supply module whose input end is connected to the positive pole of the DC input power supply, the third DC switching power supply module is the DC switching power supply module whose input end is connected to the negative pole of the DC input power supply, and the second DC switching power supply module is the remaining DC switching power supply modules connected in series between the first DC switching power supply module and the third DC switching power supply module;

[0008] The output ends of the DC switching power supply modules are connected in parallel to output the DC output power supply voltage;

[0009] The output end of the synchronous drive controller is connected to one end of the DC switching power supply module, and the input end of the synchronous drive controller is connected to the first output end of the PWM controller;

[0010] The input end of the output sampling circuit is connected to the second output end of the PWM controller, and the output end of the output sampling circuit is connected to the input end of the PWM controller.

[0011] In some embodiments, the input end includes a positive input and a negative input;

[0012] The positive input of the first DC switching power supply module is connected to the positive pole of the DC input power supply, and the negative input of the first DC switching power supply module is connected to the positive input of the first target DC switching power supply module, where the first target DC switching power supply module is the second DC switching power supply module connected in series with the first DC switching power supply module;

[0013] The positive input of the second DC switching power supply module is connected to the negative input of the previous DC switching power supply module, and the negative input of the second DC switching power supply module is connected to the positive input of the next DC switching power supply module, where the previous DC switching power supply module is the first DC switching power supply module or any other second DC switching power supply module connected in series with the second DC switching power supply module, and the next DC switching power supply module is any other second DC switching power supply module or the third DC switching power supply module connected in series with the second DC switching power supply module;

[0014] The positive input of the third DC switching power supply module is connected to the negative input of the second target DC switching power supply module, and the negative input of the third DC switching power supply module is connected to the negative pole of the DC input power supply, where the second target DC switching power supply module is the second DC switching power supply module connected in series with the third DC switching power supply module.

[0015] In some embodiments, the output end includes a negative output and a positive output;

[0016] The positive outputs of the DC switching power supply modules are connected in parallel to the positive pole of the DC output power supply voltage, and the negative outputs of the DC switching power supply modules are connected in parallel to the negative pole of the DC output power supply voltage.

[0017] In some embodiments, the DC switching power supply module includes a high-frequency transformer, a power switch tube, an absorption circuit, a rectifying and filtering circuit, a second resistor, and a second capacitor;

[0018] The output end of the synchronous drive controller is connected to the gate of the power switch tube, the source of the power switch tube is connected in series with the second resistor, the first end of the second resistor is led out to the negative input through a first connection path, and the second end of the second resistor is grounded through a second connection path;

[0019] The drain of the power switch tube is connected in series with the primary winding of the high-frequency transformer. The input end of the absorption circuit is led out to the input positive electrode through a fourth connection path, and the output end of the absorption circuit is connected in parallel with the primary winding of the high-frequency transformer;

[0020] The secondary winding of the high-frequency transformer is connected in parallel with the rectifying and filtering circuit. The first end of the rectifying and filtering circuit is led out to the output positive electrode through a fifth connection path, and the second end of the rectifying and filtering circuit is led out to the output negative electrode through a sixth connection path;

[0021] The second capacitor is connected between the input positive electrode and the input negative electrode.

[0022] In some embodiments, the synchronous drive controller is connected to the gates of the power switch tubes in all the DC switch power modules for synchronously controlling the conduction or cut-off of the power switch tubes in all the DC switch power modules.

[0023] In some embodiments, the absorption circuit includes a third capacitor, a third resistor, and a second diode;

[0024] The third capacitor is connected in parallel with the third resistor to form a parallel structure, and the second diode is connected in series with the parallel structure.

[0025] In some embodiments, the rectifying and filtering circuit includes a fourth capacitor and a fourth diode;

[0026] The fourth diode and the fourth capacitor are connected in series in sequence to form a series structure, and the secondary winding of the high-frequency transformer is connected in parallel with the series structure;

[0027] The anode of the fourth diode is connected to the first end of the fourth capacitor to form a connection node. The connection node is led out to the output positive electrode through the fifth connection path, and the second end of the fourth capacitor is led out to the output negative electrode through the sixth connection path.

[0028] In some embodiments, the first capacitor is an electrolytic capacitor, and the fourth capacitor is an electrolytic capacitor.

[0029] The embodiments of the present application at least include the following beneficial effects: A DC switch power supply series circuit provided by the present application realizes the DC conversion of high input voltage by connecting DC switch power modules in series. Through the common cooperation of the PWM controller, the synchronous drive controller, and the output sampling circuit, the working states of multiple DC switch power modules are synchronously controlled, the DC conversion efficiency is improved, and it is applicable to application scenarios with ultra-high voltage input. Description of the Drawings

[0030] Figure 1 is a schematic structural diagram of a series circuit of a DC switching power supply provided by an embodiment of the present application;

[0031] Figure 2 is a schematic circuit diagram of a DC switching power supply module in an embodiment of the present application;

[0032] Figure 3 is another schematic structural diagram of a series circuit of a DC switching power supply provided by an embodiment of the present application. Detailed implementation manners

[0033] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application. When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the embodiments of the present application. They are only examples of devices and methods consistent with some aspects of the embodiments of the present application detailed in the appended claims.

[0034] It can be understood that the terms "first", "second", etc. used in the present application can be used herein to describe various concepts, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another. For example, without departing from the scope of the embodiments of the present application, the first information can also be called the second information, and similarly, the second information can also be called the first information. Depending on the context, the words "if", "when" as used herein can be interpreted as "when...", "while...", or "in response to determining".

[0035] The terms "at least one", "a plurality of", "each", "any one", etc. used in the present application, at least one includes one, two or more than two, a plurality of includes two or more than two, each refers to each of the corresponding plurality, and any one refers to any one of the plurality.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0037] Refer to Figure 1 , Figure 1It is an optional structural schematic diagram of a series circuit of DC switching power supplies provided by an embodiment of the present application. It includes a PWM controller, a synchronous drive controller, an output sampling circuit, and multiple DC switching power supply modules. The DC switching power supply modules are connected in series, and each DC switching power supply module includes an input end and an output end;

[0038] The input ends of each DC switching power supply module are connected in parallel with a first resistor R1, a first capacitor C1, and a first diode D1;

[0039] Determine a first DC switching power supply module DC / DC1, multiple second DC switching power supply modules DC / DC21 to DC / DC2N, and a third DC switching power supply module DC / DC3 from multiple DC switching power supply modules. Among them, the first DC switching power supply module DC / DC1 is a DC switching power supply module whose input end is connected to the positive pole V+ of the DC input power supply, and the third DC switching power supply module DC / DC3 is a DC switching power supply module whose input end is connected to the negative pole V- of the DC input power supply. The second DC switching power supply module DC / DC2 is the remaining DC switching power supply modules connected in series between the first DC switching power supply module DC / DC1 and the third DC switching power supply module DC / DC3;

[0040] The output ends of each DC switching power supply module are connected in parallel to output a DC output power supply voltage;

[0041] The output end of the synchronous drive controller is connected to one end of the DC switching power supply module, and the input end of the synchronous drive controller is connected to the first output end of the PWM controller;

[0042] The input end of the output sampling circuit is connected to the second output end of the PWM controller, and the output end of the output sampling circuit is connected to the input end of the PWM controller.

[0043] In some embodiments, as Figure 1 shown, the input end of the DC switching power supply module includes an input positive pole Vin+ and an input negative pole Vin-, and the output end of the DC switching power supply module includes an output negative pole Vo- and an output positive pole Vo+.

[0044] The input positive pole Vin+ of the first DC switching power supply module is connected to the positive pole V+ of the DC input power supply, and the input negative pole Vin- of the first DC switching power supply module is connected to the input positive pole Vin+ of the first target DC switching power supply module, where the first target DC switching power supply module is the second DC switching power supply module DC / DC21 connected in series with the first DC switching power supply module;

[0045] The positive input terminal Vin+ of the second DC switching power supply module is connected to the negative input terminal Vin- of the previous DC switching power supply module, and the negative input terminal Vin- of the second DC switching power supply module is connected to the positive input terminal Vin+ of the next DC switching power supply module. Herein, the previous DC switching power supply module is the first DC switching power supply module or any other second DC switching power supply module in series with the second DC switching power supply module, and the next DC switching power supply module is any other second DC switching power supply module or the third DC switching power supply module in series with the second DC switching power supply module. Optionally, when the second DC switching power supply module is the first target DC switching power supply module DC / DC21, the corresponding previous DC switching power supply module is the first DC switching power supply module DC / DC1, and the corresponding next DC switching power supply module is DC / DC22, and so on;

[0046] The positive input terminal Vin+ of the third DC switching power supply module DC / DC3 is connected to the negative input terminal Vin- of the second target DC switching power supply module, and the negative input terminal Vin- of the third DC switching power supply module DC / DC3 is connected to the negative terminal V- of the DC input power supply. Herein, the second target DC switching power supply module is the second DC switching power supply module DC / DC2N in series with the third DC switching power supply module DC / DC3;

[0047] The positive output terminals Vo+ of each DC switching power supply module are connected in parallel to the positive terminal +Vo of the DC output power supply voltage, and the negative output terminals Vo- of each DC switching power supply module are connected in parallel to the negative terminal -Vo of the DC output power supply voltage.

[0048] In some embodiments, referring to Figure 2 , Figure 2 is an optional circuit structure diagram of the DC switching power supply module in the embodiments of the present application. The DC switching power supply module includes a high-frequency transformer T1, a power switch tube Q1, an absorption circuit, a rectifying and filtering circuit, a second resistor R2, and a second capacitor C2;

[0049] The output terminal of the synchronous drive controller is connected to the gate G of the power switch tube. The source S of the power switch tube is connected in series with the second resistor R2. The first end of the second resistor R2 is led out to the negative input terminal through a first connection path, and the second end of the second resistor R2 is grounded through a second connection path;

[0050] The drain D of the power switch tube Q1 is connected in series with the primary winding Np of the high-frequency transformer T1. The input terminal of the absorption circuit is led out to the positive input terminal Vin+ through a fourth connection path, and the output terminal of the absorption circuit is connected in parallel with the primary winding Np of the high-frequency transformer T1;

[0051] The secondary winding Ns of the high-frequency transformer T1 is connected in parallel with the rectifying and filtering circuit. The first end of the rectifying and filtering circuit is led out to the output positive terminal Vo+ through a fifth connection path, and the second end of the rectifying and filtering circuit is led out to the output negative terminal Vo- through a sixth connection path.

[0052] A second capacitor C2 is connected between the input positive terminal Vin+ and the input negative terminal Vin-.

[0053] The absorption circuit includes a third capacitor C3, a third resistor R3, and a second diode D2.

[0054] The third capacitor C3 is connected in parallel with the third resistor R3 to form a parallel structure, and the second diode D2 is connected in series with the parallel structure.

[0055] The rectifying and filtering circuit includes a fourth capacitor C4 and a fourth diode D4.

[0056] The fourth diode D4 and the fourth capacitor C4 are connected in series in sequence to form a series structure, and the secondary winding Ns of the high-frequency transformer T1 is connected in parallel with the series structure.

[0057] The anode of the fourth diode D4 is connected to the first end of the fourth capacitor C4 to form a connection node. The connection node is led out to the output positive terminal Vo+ through a fifth connection path, and the second end of the fourth capacitor C4 is led out to the output negative terminal Vo- through a sixth connection path.

[0058] In some embodiments, both the first capacitor C1 and the fourth capacitor C4 are electrolytic capacitors with a relatively large capacitance. The power switch tube Q1 is a MOSFET tube or an IGBT tube. The first diode D1 is a fast-recovery diode. The synchronous drive controller is connected to the gates of the power switch tubes in all the DC switching power supply modules for synchronously controlling the conduction or cut-off of the power switch tubes in all the DC switching power supply modules.

[0059] In some embodiments, taking the series connection of two DC switching power supply modules with a rated power of 40W and a 400VDC input as an example, referring to Figure 3 , Figure 3 is another optional structural schematic diagram of a DC switching power supply series circuit provided by an embodiment of the present application. Among them, it includes DC switching power supply modules DC / DC1 and DC / DC2, and DC / DC1 and DC / DC2 are connected in series. Assuming that the positive terminal of the DC input power supply is connected to a 750VDC DC voltage and the negative terminal of the DC input power supply is connected to a 0VDC DC voltage, the working principle of this DC switching power supply series circuit is as follows:

[0060] 1) When there is no PWM drive output, the 750 VDC DC voltage is divided into half, 375 VDC, by capacitors C1A and C1B. VC3 = VC1A = 375 VDC. At this time, R1A is used to balance the voltages across C1A, and R1B is used to balance the voltages across C1B. The positive inputs of the DC / DC1 and DC / DC2 power supplies both receive 375 VDC DC voltage.

[0061] 2) When the drive output of the PWM controller is at a high level, high levels DRA and DRB are simultaneously output through the synchronous controller, and power switch transistors Q1A and Q1B are turned on simultaneously. At this time, the 750 VDC DC voltage sequentially passes through high-frequency transformer T1A - power switch transistor Q1A - resistor R2A - high-frequency transformer T1B - power switch transistor Q1B - resistor R2B - the negative input of DC / DC2. Calculate impedances RDC1 and RDC2. RDC1 = the impedance of high-frequency transformer T1A + the impedance of power switch transistor Q1A + the impedance of resistor R2A. Similarly, RDC2 = the impedance of high-frequency transformer T1B + the impedance of power switch transistor Q1B + the impedance of resistor R2B. Since the impedance of high-frequency transformer T1A is equal to the impedance of high-frequency transformer T1B, the impedance of power switch transistor Q1A is equal to the impedance of power switch transistor Q1B, and the impedance of resistor R2A is equal to the impedance of resistor R2B, so RDC1 = RDC2.

[0062] 3) Since RDC1 and RDC2 are connected in series across the 750 VDC DC voltage, VRDC1 = VRDC2. VRDC1 = VRDC2 = 750 * RDC1 / (RDC1 + RDC2) = 375 VDC. The positive inputs of the DC / DC1 and DC / DC2 power supplies both receive 375 VDC DC voltage. The 375 VDC DC voltage is within the input voltage range of the DC switching power supply module, and the rated power of each DC switching power supply module is 40 W. Then the total power output of this DC switching power supply series circuit is 80 W.

[0063] 4) When the PWM controller samples through the output sampling circuit and finds that the output voltage reaches the requirement, the drive output is at a low level, and low levels DRA and DRB are simultaneously output through the synchronous controller to turn off power switch transistors Q1A and Q1B. This is one working cycle, and it works in this way cyclically to achieve a stable output voltage.

[0064] 5) When the power switch transistors Q1A and Q1B are turned off, due to the leakage inductance of the high-frequency transformers T1A and T1B, large spikes will be generated on the drains D of the power switch transistors Q1A and Q1B. The absorption circuit composed of D2A, C3A, and R3A absorbs the spikes of the power switch transistor Q1A within a certain range. Similarly, the absorption circuit composed of D2B, C3B, and R3B absorbs the spikes on the power switch transistor Q1B within a certain range.

[0065] A DC switching power supply series circuit provided by an embodiment of the present application realizes the DC conversion of high input voltage by connecting DC switching power supply modules in series. Through the cooperation of a PWM controller, a synchronous drive controller, and an output sampling circuit, it realizes the synchronous control of the working states of multiple DC switching power supply modules, improves the DC conversion efficiency, and is applicable to application scenarios with ultra-high voltage input.

[0066] The embodiments described in the embodiments of the present application are to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided by the embodiments of the present application. Those skilled in the art know that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0067] The preferred embodiments of the embodiments of the present application have been described above with reference to the accompanying drawings, but this does not limit the scope of rights of the embodiments of the present application. Any modifications, equivalent replacements, and improvements made by those skilled in the art without departing from the scope and essence of the embodiments of the present application shall fall within the scope of rights of the embodiments of the present application.

Claims

1. A series circuit of a DC switching power supply, characterized in that, Including: A PWM controller, a synchronous drive controller, an output sampling circuit, and multiple DC switching power supply modules; the multiple DC switching power supply modules are connected in series, and each of the DC switching power supply modules includes an input terminal and an output terminal; The input terminals of each of the DC switching power supply modules are connected in parallel with a first resistor, a first capacitor, and a first diode; Determine a first DC switching power supply module, multiple second DC switching power supply modules, and a third DC switching power supply module from the multiple DC switching power supply modules, where the first DC switching power supply module is the DC switching power supply module whose input terminal is connected to the positive pole of the DC input power supply, the third DC switching power supply module is the DC switching power supply module whose input terminal is connected to the negative pole of the DC input power supply, and the second DC switching power supply module is the remaining DC switching power supply modules connected in series between the first DC switching power supply module and the third DC switching power supply module; The output terminals of each of the DC switching power supply modules are connected in parallel to output a DC output power supply voltage; The output terminal of the synchronous drive controller is connected to one end of the DC switching power supply module, and the input terminal of the synchronous drive controller is connected to the first output terminal of the PWM controller; The input terminal of the output sampling circuit is connected to the second output terminal of the PWM controller, and the output terminal of the output sampling circuit is connected to the input terminal of the PWM controller.

2. The series circuit of the DC switching power supply according to claim 1, characterized in that, The input terminal includes an input positive pole and an input negative pole; The input positive pole of the first DC switching power supply module is connected to the positive pole of the DC input power supply, and the input negative pole of the first DC switching power supply module is connected to the input positive pole of a first target DC switching power supply module, where the first target DC switching power supply module is the second DC switching power supply module connected in series with the first DC switching power supply module; The input positive pole of the second DC switching power supply module is connected to the input negative pole of the previous DC switching power supply module, and the input negative pole of the second DC switching power supply module is connected to the input positive pole of the next DC switching power supply module, where the previous DC switching power supply module is the first DC switching power supply module or any other second DC switching power supply module connected in series with the second DC switching power supply module, and the next DC switching power supply module is any other second DC switching power supply module or the third DC switching power supply module connected in series with the second DC switching power supply module; The input positive pole of the third DC switching power supply module is connected to the input negative pole of a second target DC switching power supply module, and the input negative pole of the third DC switching power supply module is connected to the negative pole of the DC input power supply, where the second target DC switching power supply module is the second DC switching power supply module connected in series with the third DC switching power supply module.

3. The series circuit of the DC switching power supply according to claim 1, wherein, The output terminal includes an output negative pole and an output positive pole; The output positive poles of the DC switching power supply modules are connected in parallel to the positive pole of the DC output power supply voltage, and the output negative poles of the DC switching power supply modules are connected in parallel to the negative pole of the DC output power supply voltage.

4. The series circuit of the DC switching power supply according to claim 1, characterized in that, The DC switching power supply module includes a high-frequency transformer, a power switch tube, an absorption circuit, a rectifying and filtering circuit, a second resistor, and a second capacitor; The output end of the synchronous drive controller is connected to the gate of the power switch tube. The source of the power switch tube is connected in series with the second resistor. The first end of the second resistor is led out to the input negative pole through a first connection path, and the second end of the second resistor is grounded through a second connection path; The drain of the power switch tube is connected in series with the primary winding of the high-frequency transformer. The input end of the absorption circuit is led out to the input positive pole through a fourth connection path, and the output end of the absorption circuit is connected in parallel with the primary winding of the high-frequency transformer; The secondary winding of the high-frequency transformer is connected in parallel with the rectifying and filtering circuit. The first end of the rectifying and filtering circuit is led out to the output positive pole through a fifth connection path, and the second end of the rectifying and filtering circuit is led out to the output negative pole through a sixth connection path; The second capacitor is connected between the input positive pole and the input negative pole.

5. The series circuit of DC switching power supplies according to claim 4, wherein The synchronous drive controller is connected to the gates of the power switch tubes in all the DC switching power supply modules for synchronously controlling the conduction or cut-off of the power switch tubes in all the DC switching power supply modules.

6. The series circuit of DC switching power supplies according to claim 4, wherein, The absorption circuit includes a third capacitor, a third resistor, and a second diode; The third capacitor is connected in parallel with the third resistor to form a parallel structure, and the second diode is connected in series with the parallel structure.

7. The series circuit of DC switching power supplies according to claim 4, characterized in that, The rectifying and filtering circuit includes a fourth capacitor and a fourth diode; The fourth diode and the fourth capacitor are connected in series in sequence to form a series structure, and the secondary winding of the high-frequency transformer is connected in parallel with the series structure; The anode of the fourth diode is connected to the first end of the fourth capacitor to form a connection node. The connection node is led out to the output positive pole through the fifth connection path, and the second end of the fourth capacitor is led out to the output negative pole through the sixth connection path.

8. The series circuit of DC switching power supplies according to claim 7, characterized in that, The first capacitor is an electrolytic capacitor, and the fourth capacitor is an electrolytic capacitor.

Images