High-voltage power supply based on linear proportion voltage stabilizing source

Abstract

The invention relates to a high-voltage power supply based on a linear proportional voltage stabilizing source, and the main loop of the power supply comprises a power input port, an inverter, an LLC resonator, a voltage doubling rectifying circuit, a proportional linear voltage stabilizing circuit, a voltage and current detection circuit, and a power output port. The power supply input port, the inverter, the LLC resonator, the voltage doubling rectifying circuit, the proportional linear voltage stabilizing circuit and the power supply output port are connected in sequence; the voltage and current detection circuit acquires voltage data and current data of a power supply main loop; the proportional linear voltage stabilizing circuit at least comprises a triode Q5, a triode Q6, a resistor R1, a resistor R2 and a capacitor C1, the triode Q5 and the triode Q6 form a Darlington structure with the base of the triode Q5 as a control end, and the Darlington structure is connected to the positive output end of the voltage doubling rectifying circuit. The positive output end of the voltage-multiplying rectifying circuit is connected back to the negative output end of the voltage-multiplying rectifying circuit through the resistor R1 and the resistor R2 in sequence to form series-connection partial voltage, the partial voltage is connected to the control end of the Darlington structure, and the capacitor C1 is connected with the resistor R2 in parallel.

Description

Technical Field

[0001] The invention belongs to the field of power electronics, in particular to the field of power supplies, and specifically relates to a simulated load which can independently test multiple power supplies of the same voltage level and has an adjustable load. Background Art

[0002] In high-voltage output situations, such as hash neutron source power supplies, laser power supplies, high-voltage ozone power supplies, and demisting power supplies, the output voltage is usually several thousand volts, or even tens of kilovolts or higher. This type of power supply has the following parameter requirements: 1) The output voltage is infinitely adjustable and can be set to an output of 0V to the highest voltage; 2) The output voltage ripple is small, and some are even ≤0.0001%; ​​3) The output voltage accuracy is ≤0.0005%; 4) The output filter circuit must have a discharge function, and the discharge from the highest voltage to 0V is no more than 100ms. In order to achieve infinitely adjustable voltage, the power supply adopts a closed-loop output voltage method. The main circuit diagram is as follows Figure 1 As shown, the power supply consists of power input, inverter, LLC resonance, voltage doubler rectification, filtering, voltage and current detection, power output, control center, etc. After the DC power supply is input, it is first converted into high-frequency AC power through the inverter unit, then isolated and output through the transformer, and then outputs a high voltage through the voltage doubler rectification circuit, and then filtered through the filter circuit, and finally the voltage and current are sampled and output.

[0003] from Figure 1 It can be seen that the filter part uses capacitors. In order to achieve low ripple output, the filter capacitor will be designed to be large to meet the small ripple requirements of the power supply output. Because the filter capacitor is designed to be too large, after the inverter end is turned off, it will take a long time for the output voltage to drop to 0V. Obviously, it is difficult to meet the fourth point.

[0004] Disadvantages of conventional high voltage power supply design:

[0005] 1. Due to the existence of filter capacitors, the power supply startup time is very long, and the output voltage drop time after shutdown is also very long, which cannot meet the application occasions that require fast startup and discharge time;

[0006] 2. The capacitor is directly added to the output high voltage end. The voltage level is high and the capacity needs to be large, resulting in a large capacitor volume and high cost;

[0007] 3. Poor dynamic response, closed-loop regulation easily causes low-frequency oscillation;

[0008] 4. The output filter capacitor is too large, which significantly increases the economic cost. Summary of the invention

[0009] In order to solve the above design shortcomings of the power supply, a linear voltage regulator module is set at the output end of the power supply, which can not only reduce the ripple voltage, but also reduce the filter capacitor. However, the linear voltage regulator modules on the market are all fixed voltage ones, and the voltage is very small. Common voltage regulator modules are: 7805, 7815, 7824, etc. In other words, after the output voltage of the hardware circuit is configured, no matter how high the input voltage is, the voltage regulator module will output a fixed and very low voltage. In this way, the power supply cannot achieve infinitely adjustable output voltage. In addition, this method has a fatal disadvantage: when the voltage at the input end of the voltage regulator module is very high, the loss of the voltage regulator module is very large, P 损 =U 压降 *I,P 损 is the power loss of the voltage regulator module, U 压降 is the voltage drop of the voltage stabilizing module, and I is the current passing through the voltage stabilizing module. In order to solve the problems in the prior art, the present invention proposes a high voltage power supply based on a linear proportional voltage stabilizing source, the purpose of which is to solve the problems in the prior art while achieving high voltage stepless adjustment and low ripple high voltage output.

[0010] To this end, a high-voltage power supply based on a linear proportional voltage stabilization source is provided. The main circuit of the power supply comprises a power input port, an inverter, an LLC resonator, a voltage doubling rectifier circuit, a proportional linear voltage stabilization circuit, a voltage and current detection circuit and a power output port. The power input port, the inverter, the LLC resonator, the voltage doubling rectifier circuit, the proportional linear voltage stabilization circuit and the power output port are connected in sequence, and the voltage and current detection circuit collects voltage data and current data of the main circuit of the power supply; the proportional linear voltage stabilization circuit at least comprises a transistor Q5, a transistor Q6, a resistor R1, a resistor R2 and a capacitor C1. The transistors Q5 and the transistor Q6 form a Darlington structure with the base of the transistor Q5 as the control end. The Darlington structure is connected to the positive output end of the voltage doubling rectifier circuit. The positive output end of the voltage doubling rectifier circuit is connected back to the negative output end of the voltage doubling rectifier circuit via resistors R1 and R2 in sequence to form a series voltage divider. The voltage divider voltage is connected to the control end of the Darlington structure. The capacitor C1 is connected in parallel with the resistor R2.

[0011] As an improved solution, a proportional linear voltage regulator circuit is placed between the voltage doubler rectifier circuit and the voltage and current detection circuit; the output voltage detected by the voltage and current detection circuit is used as the outer loop PID, and the output current detected by the voltage and current detection circuit is used as the inner loop PID to control the inverter.

[0012] As another improvement, the inverter H-bridge switch tube in the inverter adopts CMOS tube.

[0013] The resonant inductor in the LLC resonator is made of ferrite material, the winding is a multi-strand copper wire, and the resonant capacitor is a CBB capacitor. Furthermore, the transformer is made of high-frequency ferrite material, the primary-secondary turns ratio is 1:9, and the primary-secondary winding is wound in layers with a multi-strand copper wire.

[0014] As another improvement scheme, it includes a voltage regulator tube Z1, the anode of the voltage regulator tube Z1 is connected to the emitter of the transistor Q6, and the cathode is connected to the collector of the transistor Q5; the voltage regulation value of the voltage regulator tube Z1 is less than the forward withstand voltage value of the transistors Q6 and Q5.

[0015] As another improvement, the voltage detection in the voltage and current detection circuit uses a resistor series voltage division method for detection, and the resistor is a low temperature drift resistor. The current detection in the voltage and current detection circuit uses a sampling circuit composed of a high-precision small resistance resistor through an operational amplifier differential.

[0016] Advantages of the present invention:

[0017] 1. Based on proportional linear voltage regulation, the filtering effect of any output voltage is ensured, which must be proportionally higher than the output voltage before voltage regulation.

[0018] 2. Add filter capacitors to the proportional linear voltage regulator to ensure the filtering effect of any output voltage while achieving low ripple output of any output voltage.

[0019] 3. Placing the filter capacitor at the base end of the transistor greatly reduces the capacity of the capacitor and indirectly reduces the volume of the capacitor.

[0020] 4. There is no filtering circuit at the output end of the power supply, which enables 0 time to reduce the voltage output from high voltage to 0 voltage output.

[0021] 5. The voltage following function and closed-loop control based on proportional linear voltage regulation ensure low ripple output of the full range output voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The topological structure diagram of the conventional high voltage power supply is shown;

[0023] Figure 2 A high voltage power supply topology diagram based on a proportional linear voltage regulator is shown;

[0024] Figure 3 The voltage ripple simulation comparison diagram before and after the proportional linear voltage regulator is shown;

[0025] Figure 4 A control block diagram is shown;

[0026] Figure 5 The power supply system block diagram is shown;

[0027] Figure 6 A proportional linear voltage regulator with filtering and protection is shown;

[0028] Figure 7 The voltage detection circuit topology diagram is shown. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] Figure 2 The topology diagram of the high-voltage power supply based on the proportional linear voltage regulator circuit is given. The main circuit of the power supply consists of the power input port, inverter, LLC resonator, voltage doubler rectifier circuit, proportional linear voltage regulator circuit, voltage and current detection circuit and power output port. The power input port, inverter, LLC resonator, voltage doubler rectifier circuit, proportional linear voltage regulator circuit and power output port are connected in sequence, and the voltage and current detection circuit collects the voltage data and current data of the main circuit of the power supply. After the voltage doubler rectifier, there is no direct filtering unit, but only a proportional linear voltage regulator circuit with built-in filtering function. The high-voltage direct current from the voltage doubler rectifier contains high ripple voltage. After passing through the proportional linear voltage regulator circuit with filtering function, the ripple voltage decays sharply, and finally a low-ripple high-voltage power supply output is obtained.

[0031] The proportional linear voltage regulator circuit with filtering function is composed of transistors, resistors, capacitors, etc. Transistors Q5 and Q6 form a Darlington structure connected to the positive output end of the voltage doubler rectifier circuit to maximize its amplification factor. The base of transistor Q5 is the control end. The positive output end of the voltage doubler rectifier circuit is connected back to the negative output end of the voltage doubler rectifier circuit through resistors R1 and R2 in sequence. Resistors R1 and R2 form a series voltage divider, which is directly connected to the control end of the Darlington structure, that is, the base of transistor Q5 in the figure, to form a follower circuit, that is, the output voltage of Q6 is equal to the voltage of the base of Q5. Therefore, the smaller the ripple of the base voltage of Q5, the smaller the ripple of the power supply output. Based on this, as long as capacitor C1 is connected in parallel with resistor R2, a good filtering effect of the entire power supply can be achieved. Figure 3 As shown in the figure, at the front end of the linear proportional voltage regulator (that is, the output end of the voltage doubler), if the input power is DC4200V, the ripple voltage amplitude is 5V, and the frequency is 20kHz, after passing through the proportional linear regulator with filtering function, the ripple voltage of the output DC voltage is less than 5mV, which shows that the filtering effect is very significant. The resistor R1 of the proportional regulator with filtering function is 10MΩ, R2 is 300MΩ, and the capacitor C1 is 0.05uF.

[0032] But this also creates a problem. After the voltage passes through the proportional linear voltage regulator circuit, there will be a certain voltage drop. If this circuit is hastily added to the back end of any high-voltage power supply to reduce ripple, the output voltage of the original power supply will be low. If the original power supply outputs DC4000V, after adding the linear proportional voltage regulator of this invention, the actual output voltage may only be DC3900V. Therefore, when using the high-voltage proportional linear voltage regulator circuit of the present invention, corresponding control must also be provided. First, in terms of topological structure layout, the proportional linear voltage regulator circuit is placed between the voltage doubling rectifier circuit and the voltage and current detection circuit. The output voltage detected by the voltage and current detection circuit is used as the outer loop PID, and the output current detected by the voltage and current detection circuit is used as the inner loop PID to control the inverter. The control block diagram is shown as follows. Figure 4 shown.

[0033] The premise of using the present invention is that the highest voltage output by the voltage doubler rectifier circuit is ≧ the power supply output voltage + the voltage drop of the proportional linear voltage regulator circuit.

[0034] like Figure 5 As shown in the figure, the power supply system consists of voltage and current detection ⑤, control and drive ④, MCU ③ and operation panel ⑥. Voltage and current detection ⑤ mainly detects the voltage and current at the output end of the main circuit ①, and provides the detection to MCU ③. MCU ③ processes the voltage, current, communication and other data, controls ④ drive and controls the corresponding switch tube and some timing logic.

[0035] In order to achieve low input voltage and high output voltage, the inverter H-bridge switch tube in the inverter uses CMOS tube. When the input voltage is DC48V, the voltage level is increased to 100V. Furthermore, the resonant inductor Lr1 in the LLC resonator is made of ferrite material, the winding is multi-strand copper wire, and the resonant capacitor is a CBB capacitor. When the input voltage is DC48V, the voltage level is 200V. On this basis, the transformer is made of high-frequency ferrite material. When the input voltage is DC48V and the maximum output voltage is DC4000V, the primary-secondary turns ratio is 1:9, and the primary-secondary winding is wound in layers with multi-strand copper wire.

[0036] When the input voltage is DC48V and the maximum output voltage is DC4000V, the voltage doubler rectifier circuit has 6 levels, that is, 6 times the voltage. For this reason, the diode withstand voltage value is configured to DC1500V and the capacitor withstand voltage value is configured to 1000V.

[0037] In the present invention, the proportional linear voltage stabilization circuit adopts multi-stage resistor voltage division, which is then connected to the base of the transistor and connected in parallel with a capacitor. In the power supply with an output voltage of DC4000V, the resistor R1=10MΩ, R2=300MΩ, and the capacitor C1=0.05uF is connected in parallel to R2. The transistor adopts a Darlington structure. In order to prevent the transistor from being damaged when powered on, in actual engineering applications, the following is made: Figure 6 As shown, a voltage regulator tube Z1 is connected, the anode of the voltage regulator tube Z1 is connected to the emitter of the transistor Q6, and the cathode is connected to the collector of the transistor Q5. The voltage regulation value of the voltage regulator tube Z1 is less than the forward withstand voltage value of the transistors Q6 and Q5.

[0038] Furthermore, the voltage detection is performed by means of resistor series voltage division, and the resistor is selected as a low temperature drift resistor, such as Figure 7 The current detection circuit is shown in Figure 2 A high-precision small-value resistor is set at the position shown in the current sensor, and then the signal enters the MCU after passing through the sampling circuit composed of the operational amplifier differential. The MCU uses LSC335 and runs at a frequency of 150MHz. The PID algorithm is implemented in the MCU, and the calculated value is output to the corresponding IO port, and then the CMOS and other devices are controlled through the drive circuit.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A high voltage power supply based on a linear proportional voltage regulator, characterized in that: The main power supply circuit includes a power supply input port, an inverter, an LLC resonator, a voltage doubler rectifier circuit, a proportional linear voltage regulator circuit, a voltage and current detection circuit, and a power supply output port. The power supply input port, the inverter, the LLC resonator, the voltage doubler rectifier circuit, the proportional linear voltage regulator circuit, and the power supply output port are connected in sequence, and the voltage and current detection circuit collects voltage data and current data of the main power supply circuit; The proportional linear voltage stabilization circuit at least includes transistor Q5, transistor Q6, resistor R1, resistor R2, and capacitor C1. The transistor Q5 and transistor Q6 form a Darlington structure with the base of the transistor Q5 as the control end. The Darlington structure is connected to the positive output end of the voltage doubler rectifier circuit. The positive output end of the voltage doubler rectifier circuit is connected back to the negative output end of the voltage doubler rectifier circuit in sequence through resistors R1 and R2 to form a series voltage divider. The divided voltage is connected to the control end of the Darlington structure. The capacitor C1 is connected in parallel with the resistor R2.

2. The high voltage power supply according to claim 1, characterized in that: The proportional linear voltage stabilizing circuit is placed between the voltage doubling rectifier circuit and the voltage and current detection circuit; The output voltage detected by the voltage and current detection circuit is used as the outer loop PID, and the output current detected by the voltage and current detection circuit is used as the inner loop PID to control the inverter.

3. The high voltage power supply according to claim 1, characterized in that: The inverter H-bridge switch tubes in the inverter use CMOS tubes.

4. The high voltage power supply according to claim 3, characterized in that: The resonant inductor in the LLC resonator is made of ferrite, the winding wire is multi-strand copper wire, and the resonant capacitor is a CBB capacitor.

5. The high voltage power supply according to claim 4, characterized in that: The transformer is made of high-frequency ferrite material, the primary-secondary turns ratio is 1:9, and the primary-secondary winding is wound in layers with multiple strands of copper wire.

6. The high voltage power supply according to claim 1, characterized in that: It includes a voltage regulator tube Z1, wherein the anode of the voltage regulator tube Z1 is connected to the emitter of the transistor Q6, and the cathode is connected to the collector of the transistor Q5; The voltage stabilization value of the voltage regulator tube Z1 is less than the forward withstand voltage value of the transistors Q6 and Q5.

7. The high voltage power supply according to claim 1, characterized in that: The voltage detection in the voltage and current detection circuit adopts the resistor series voltage division method for detection, and the resistor is a low temperature drift resistor.

8. The high voltage power supply according to claim 7, characterized in that: The current detection in the voltage and current detection circuit adopts a sampling circuit composed of high-precision small-resistance resistors and differential op amps.

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