A wide input DC voltage regulator control topology and method

Abstract

The application discloses a kind of wide input DC voltage stabilizing control topology circuit and control method, it is characterized in that: the circuit can obtain stable same polarity DC output voltage when input voltage is higher or lower than output voltage, it is especially suitable for power DC screen control bus voltage stabilization;The circuit includes DC input unit, self-stabilizing voltage reduction unit, hysteresis control bypass unit, Boost unit and DC output unit;The self-stabilizing voltage reduction unit is connected to DC input unit, the hysteresis bypass control unit is connected to the charging switch tube of self-stabilizing voltage reduction unit, the Boost unit is connected to self-stabilizing voltage reduction unit output, the DC output unit is connected to Boost unit output, and the Boost unit is connected to load.The application has the advantages compared with prior art: the application has simple structure, low cost, high efficiency, good reliability, wide applicability, and can realize same polarity voltage output.

Description

Technical Field

[0001] This invention relates to the field of power electronics, specifically to a wide-input DC voltage regulator control topology circuit and control method. Background Technology

[0002] Currently, DC control systems for power applications employ silicon chain control for bus voltage regulation, utilizing multiple sets of series-connected silicon diodes to achieve bus voltage regulation. The main problems with this method are: large size, slow response speed, and inability to adjust when the input voltage is lower than the control bus voltage. Furthermore, silicon chain control for voltage regulation consumes a lot of energy. For example, with a 5-stage silicon chain and an output current of 20A, the annual energy consumption of the silicon chain voltage regulator is:

[0003]

[0004] Using a chopper circuit, which allows the switching transistor to operate only in switching mode, can significantly reduce the power consumption of the voltage regulator. Commonly used chopper circuit topologies with wide input voltage ranges include Buck-Boost circuits and Cuk circuits. However, both of these topologies produce reverse polarity output voltages, which cannot meet the requirement of the DC power supply control bus for a voltage output of the same polarity. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the above-mentioned technical defects and provide a wide-input DC voltage regulation control topology circuit and control method that is simple in structure, low in cost, high in efficiency, reliable, widely applicable, and capable of achieving the same polarity voltage output.

[0006] To solve the above problems, the technical solution of the present invention is: a wide input DC voltage regulation control topology circuit and control method, characterized in that: the circuit can obtain a stable DC output voltage of the same polarity when the input voltage is higher or lower than the output voltage;

[0007] The circuit includes a DC input unit, a self-stabilizing buck unit, a hysteresis control bypass unit, a boost unit, and a DC output unit.

[0008] The self-stabilizing buck unit is connected to the DC input unit, the hysteresis bypass control unit is connected in parallel to the charging switch of the self-stabilizing buck unit, the boost unit is connected to the output of the self-stabilizing buck unit, the DC output unit is connected to the output of the boost unit, and the boost unit is connected to the load.

[0009] Furthermore, the input voltage is higher than the output voltage, and the self-stabilizing buck unit uses circuit negative feedback to reduce the input DC power supply voltage. The output voltage value is determined by the voltage division ratio of the first resistor and the second resistor.

[0010] Furthermore, when the base voltage of the buck charging switch is higher than the emitter voltage, the switch is turned on, the capacitor is charged, and the boost unit is powered.

[0011] Preferably, when the capacitor voltage is charged to the base voltage, the switch is turned off, and the energy stored in the capacitor provides power to the Boost unit.

[0012] Furthermore, when the input voltage is 10%-20% lower than the output voltage, the switch of the hysteresis bypass control unit is closed, and the input power supply directly provides power to the Boost unit.

[0013] Furthermore, the switching transistor of the hysteresis bypass control unit adopts hysteresis control, and the hysteresis loop width is generally 10V-30V.

[0014] Furthermore, the output of the hysteresis bypass control unit is connected to the voltage divider resistor of the self-stabilizing buck unit through a fast recovery diode, thereby clamping the control electrode of the switching transistor of the self-stabilizing buck unit.

[0015] Furthermore, the hysteresis bypass control is controlled by a microprocessor. By acquiring the DC input voltage, the control signal of the hysteresis bypass control unit is output according to the hysteresis control algorithm, and after isolation and amplification, it controls the conduction and cutoff of the switching transistor.

[0016] Furthermore, the output voltage of the self-stabilizing buck unit provides a stable DC output voltage of the same polarity to the load through the Boost boost circuit.

[0017] Furthermore, the Boost circuit employs a closed-loop PI control technology to maintain a stable output voltage even when the input voltage fluctuates.

[0018] Preferably, the control signal of the Boost circuit switching transistor is generated by a dedicated control chip or microprocessor, and after amplification, drives the Boost circuit switching transistor to turn on and off.

[0019] Furthermore, the circuit includes input and output protection circuits.

[0020] The advantages of this invention compared to existing technologies are:

[0021] (1) The output terminal of the charging switch of the self-stabilizing buck unit is connected to a voltage regulator capacitor. When the voltage of the voltage regulator capacitor is lower than the voltage division value of the voltage divider resistor, the base voltage of the charging switch is higher than the emitter voltage. The power supply charges the base of the switch through the first voltage divider resistor and the current limiting resistor, and the switch automatically turns on. The power supply energy charges the voltage regulator capacitor and provides power to the Boost unit through the switch. When the charging switch of the self-stabilizing buck unit is turned on, the voltage of the voltage regulator capacitor gradually increases with the charging time. When the voltage of the voltage regulator capacitor is close to the voltage division value of the voltage divider resistor, the charging switch is turned off. At this time, the voltage regulator capacitor provides power to the Boost unit.

[0022] (2) The hysteresis bypass control switch is connected in parallel with the self-stabilizing buck switch. When the power supply voltage is low, when the hysteresis bypass control switch is closed, the power supply is supplied to the Boost boost unit through the hysteresis bypass switch. The self-stabilizing buck unit switch is forced to turn off by applying a reverse voltage between the ce and the switch. The hysteresis bypass control switch adopts hysteresis control. Generally, the hysteresis loop width is set to 20V. The hysteresis control signal is generated by the microprocessor and driven to turn on and off the hysteresis bypass control switch after isolation and amplification.

[0023] (3) If the input voltage of the Boost converter is V i The on-time of the switching transistor is T. on If the duty cycle of the switching transistor is T, then the output voltage is V. o :

[0024]

[0025] (4) The DC output unit includes an overvoltage protection circuit, a voltage sampling circuit, and a current sampling circuit. The overvoltage protection circuit samples the varistor, the voltage sampling circuit uses voltage divider resistors to sample the output voltage, and the current sampling circuit uses series sampling resistors to sample the output current. The wide-input DC voltage regulator control circuit uses a 32-bit ARM microprocessor as the main controller. The functional modules include: auxiliary power supply module, input voltage sampling module, input soft start control module, output voltage sampling module, output current sampling module, hysteresis bypass control module, status indication module, dry contact output module, and communication module. Attached Figure Description

[0026] Figure 1 This invention relates to a wide-input range DC voltage regulation control topology circuit and control method, which is the basic component of the wide-input range DC voltage regulation control topology circuit.

[0027] Figure 2 This is a schematic diagram of the method for obtaining the DC control bus in the wide-input DC voltage regulation control topology circuit and control method of the present invention.

[0028] Figure 3 This is a block diagram of the voltage regulation control topology circuit of the wide input DC voltage regulation control topology circuit and control method of the present invention.

[0029] Figure 4 This is the basic component of the Buck topology circuit of the wide-input DC voltage regulation control topology circuit and control method of the present invention.

[0030] Figure 5 This is a schematic diagram illustrating the hysteresis control principle of a wide-input DC voltage regulator control topology circuit and control method according to the present invention.

[0031] Figure 6 This is a microprocessor control function block diagram of a wide-input DC voltage regulation control topology circuit and control method according to the present invention. Detailed Implementation

[0032] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals.

[0033] It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions shown in the attached diagram, while the terms “inside” and “outside” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0034] To make the content of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0035] Example 1

[0036] This embodiment provides a voltage stabilization control circuit for a DC power supply busbar. For the method of obtaining the DC power supply busbar control circuit, please refer to [link to relevant documentation]. Figure 2 As shown.

[0037] The DC power supply bus voltage is generated by batteries and power modules. Due to battery charging and discharging, the voltage fluctuates around 240VDC, and in extreme cases, it can drop to around 100VDC. The control bus provides power to critical loads, requiring the control voltage to be stable at 220VDC ±5%.

[0038] Based on the requirements of the voltage regulator unit and the characteristics of DC power supply panels, this embodiment proposes a DC voltage regulator control topology circuit with a wide input range. See the circuit structure diagram below. Figure 1 The core component consists of three units: a self-stabilizing buck converter, a hysteresis bypass control unit, and a boost converter, such as... Figure 3 As shown.

[0039] The output DC voltage regulator circuit uses a Boost circuit as the basic voltage regulator topology. The relationship between the input and output voltages of the Boost voltage regulator circuit is as follows:

[0040]

[0041] Where: V o The input voltage, which is the control bus voltage.

[0042] V i Input voltage;

[0043] T on This refers to the on-time of the switching transistor Q3;

[0044] T represents the duty cycle of the switching transistor.

[0045] As can be seen from the output formula of the Boost voltage regulator circuit, this circuit can only work in boost mode and cannot work in buck mode. In order to achieve a stable output voltage when the input voltage is higher or lower than the output voltage, the closing bus needs to be stepped down. When the voltage of the closing bus is higher than the input voltage, the voltage is reduced to below the input voltage by the step-down unit and then regulated by the Boost voltage regulator circuit.

[0046] A general-purpose non-isolated buck converter can use a Buck circuit, as shown in the circuit diagram below. Figure 4 As shown, by controlling the on and off states of the high-frequency switching transistor Q1, an output DC voltage lower than the input voltage is obtained.

[0047] The self-stabilizing step-down unit proposed in this system is as follows: Figure 1 As shown. Resistors R1 and R2 are voltage divider resistors. By changing the ratio of resistors R1 and R2, the output voltage of the self-stabilizing buck converter can be changed. Ignoring the voltage drop across the switching transistor Q1, the formula for calculating the output voltage can be expressed as:

[0048]

[0049] Resistor R3 is the current-limiting resistor for switch Q1. When the voltage on the output stabilizing capacitor CD1 of switch Q1 is lower than the voltage division value of R1 and R2, switch Q1 is turned on, and the DC output power supply charges the stabilizing capacitor CD1 through Q1, while providing power to the subsequent Boost circuit.

[0050] When the voltage across the output voltage regulator capacitor CD1 of the switching transistor Q1 is equal to the voltage division value of R1 and R2, the switching transistor Q1 is turned off, and the voltage regulator capacitor CD1 provides power to the subsequent Boost circuit.

[0051] The self-stabilizing step-down unit is essentially a self-stabilizing closed-loop negative feedback circuit. The voltage is given by the voltage division value of R1 and R2, and the feedback value is the voltage on the stabilizing capacitor CD1. This circuit has a simple structure, good voltage regulation performance, fast response speed, and does not require any other external control signals.

[0052] When the input voltage is lower than the output voltage, the hysteresis bypass control unit starts operating, and switch Q2 closes. This circuit has a self-locking function for the self-stabilizing buck converter. When the hysteresis bypass control unit switch is closed, the output emitter voltage of switch Q1 in the self-stabilizing buck converter is equal to the input power supply voltage. Q1 is reverse biased, Q1 automatically latches, and the output is cut off. At this time, the input power supply directly provides power to the Boost converter.

[0053] To prevent the reverse voltage of the switch Q1 in the self-stabilizing buck unit from being too high and breaking down the switch, a fast recovery diode D1 is connected in parallel with the control electrode of the switch Q1 in the self-stabilizing buck unit to clamp the control electrode voltage of Q1. Ignore the forward conduction voltage drop of diode D1, and the voltage across the voltage divider resistor R2 is the power supply voltage.

[0054] To prevent the switching transistor Q2 of the hysteresis bypass control unit from jittering near the switching voltage, hysteresis control is used for Q2. The hysteresis control characteristics are as follows: Figure 5 As shown, when the power supply voltage rises above 200V, the hysteresis control outputs a low voltage, and the switching transistor Q2 is turned off. At this time, the self-stabilizing buck unit is activated, and the power supply voltage passes through the self-stabilizing buck unit to provide power to the Boost unit. When the power supply voltage drops below 180V, the hysteresis control outputs a high voltage, and the switching transistor Q2 is turned on. At this time, the self-stabilizing buck unit is locked out, and the power supply voltage passes through Q2 to provide power to the Boost unit.

[0055] The hysteresis control characteristics are implemented by a microprocessor, and the microprocessor functional block diagram is as follows: Figure 6 As shown, the microprocessor uses a 32-bit ARM processor as its core and provides a 3.3V operating voltage to the microprocessor through an auxiliary power supply circuit. In addition to hysteresis control, the microprocessor also performs input voltage sampling, input soft start control, output voltage sampling, output current sampling, status I / O, and serial communication functions.

[0056] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A wide-input DC voltage regulator control topology circuit and control method, characterized in that: The circuit can obtain a stable DC output voltage of the same polarity whether the input voltage is higher or lower than the output voltage. The circuit includes a DC input unit, a self-stabilizing buck unit, a hysteresis bypass control unit, a boost unit, and a DC output unit. The self-stabilizing buck unit is connected to the DC input unit, the hysteresis bypass control unit is connected in parallel to the charging switch of the self-stabilizing buck unit, the boost unit is connected to the output of the self-stabilizing buck unit, the DC output unit is connected to the output of the boost unit, and the boost unit is connected to the load. The self-stabilizing step-down unit includes a first resistor R1, a second resistor R2, a third resistor R3, and a first transistor Q1; the hysteresis bypass control unit includes a first diode D1 and a first switch Q2; the first terminal of the first resistor R1, the collector of the first transistor Q1, and the first terminal of the first switch Q2 are all connected to the closing bus; the second terminal of the first resistor R1 is connected to the first terminal of the second resistor R2, the first terminal of the third resistor R3, and the cathode of D1, respectively; the second terminal of the second resistor R2 is grounded; the second terminal of the third resistor R3 is connected to the collector of the first transistor Q1; the emitter of the first transistor Q1 is connected to the anode of the first diode D1 and the second terminal of the first switch Q2.

2. The wide-input DC voltage regulator control topology and control method according to claim 1, characterized in that: The input voltage is higher than the output voltage. The self-stabilizing step-down unit uses circuit negative feedback to step down the input DC power supply. The output voltage value is determined by the voltage division ratio of the first resistor and the second resistor.

3. The wide-input DC voltage regulator control topology and control method according to claim 1, characterized in that: (1) When the base voltage of the buck charging switch is higher than the emitter voltage, the switch is turned on, the capacitor is charged and the boost unit is powered. (2) When the capacitor voltage is charged to the base voltage threshold, the switch is turned off, and the capacitor energy storage provides power to the Boost boost unit.

4. The wide-input DC voltage regulator control topology and control method according to claim 1, characterized in that: When the input voltage is 10% to 20% lower than the output voltage, the switch of the hysteresis bypass control unit is closed, and the input power supply directly provides power to the Boost unit.

5. The wide-input DC voltage regulator control topology and control method according to claim 4, characterized in that: The hysteresis loop width of the hysteresis bypass control unit is generally taken as 10V~30V.

6. The wide-input DC voltage regulator control topology and control method according to claim 4, characterized in that: The output of the hysteresis bypass control unit is connected to the voltage divider resistor of the self-stabilizing buck unit through a fast recovery diode, thereby clamping the control electrode of the switching transistor of the self-stabilizing buck unit.

7. The wide-input DC voltage regulator control topology and control method according to claim 4, characterized in that: The hysteresis bypass control is controlled by a microprocessor. It collects the DC input voltage, outputs a hysteresis control signal according to the hysteresis control algorithm, and controls the conduction and cutoff of the switching transistor after isolation and amplification.

8. The wide-input DC voltage regulator control topology and control method according to claim 1, characterized in that: The output voltage of the self-stabilizing buck unit provides a stable DC output voltage of the same polarity to the load through the Boost boost circuit.

9. The wide-input DC voltage regulator control topology and control method according to claim 8, characterized in that: The Boost converter circuit uses closed-loop PI control technology, which can maintain a stable output voltage even when the input voltage fluctuates. The control signal of the Boost converter circuit switching transistor is generated by a dedicated control chip or microprocessor, and after amplification, it drives the Boost converter circuit switching transistor to turn on and off.

10. The wide-input DC voltage regulator control topology and control method according to claim 1, characterized in that: The circuit is equipped with input and output protection circuits.

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