High-voltage power supply device with wide voltage range output and control method

Abstract

The invention relates to the technical field of high-voltage power supplies, in particular to a high-voltage power supply device with wide voltage range output and a control method.The device comprises a high-voltage direct-current structure and a closed-loop control structure which are connected with each other, and the closed-loop control structure is used for conducting feedback adjustment on high-voltage direct-current voltage output by the high-voltage direct-current structure; the high-voltage direct-current structure comprises an alternating-current power grid input module, a voltage reduction module, a high-frequency inverter, a high-voltage transformer and a voltage doubling rectifying circuit, and the voltage reduction module is used for rectifying alternating current output by the alternating-current power grid input module and reducing direct-current voltage after the alternating current is rectified. The voltage reduction module is additionally arranged in front of the high-frequency inverter, so that the voltage of the direct-current bus is effectively reduced, stable output in a wide voltage range and a wide load range is realized, and the lowest no-load output voltage of the high-voltage power supply is greatly reduced from about 5% of rated voltage to 0.3% of rated voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of high voltage power supplies, and in particular to a high voltage power supply device with wide voltage range output and a control method thereof. Background Art

[0002] High voltage DC power supplies are widely used in many high-tech and industrial fields, especially in ion beam and electron beam related technologies. In these application scenarios, high voltage power supplies are mainly used to power accelerating electrodes and suppressing electrodes. Accelerating electrodes accelerate charged particles in ion or electron sources by applying high voltage electric fields to reach the required energy level. Suppressing electrodes are used to prevent secondary heterogeneous particles generated during beam generation from being accelerated and returning to the electron or ion source, thereby avoiding damage to the source.

[0003] In order to ensure the stability and accuracy of the ion beam or electron beam, the high-voltage power supply needs to maintain a highly stable output under wide voltage and load conditions. However, traditional high-voltage power supply designs, such as those using a full-bridge resonant converter topology, have some problems under no-load conditions. Due to the slight error in the switching delay time of the two arms of the full bridge and the presence of energy storage elements in the resonant converter, a small amount of energy is still transferred to the high-voltage side when no-load. This results in the low output voltage of the high-voltage power supply usually only reaching about 5% of the rated voltage, which cannot meet the requirements of some applications for lower voltages.

[0004] In order to reduce the output voltage of the high-voltage power supply under no-load conditions, the prior art generally adopts the method of increasing a dummy load or reducing the resistance of a sampling resistor. However, these methods may increase system losses and may cause a drastic change in the temperature inside the chassis, thereby affecting the stability and reliability of the high-voltage power supply. Summary of the invention

[0005] In view of this, the present invention provides a high-voltage power supply device and a control method with a wide voltage range output to solve the problem that the prior art will increase system losses and may cause drastic changes in the internal temperature of the chassis, thereby affecting the stability and reliability of the high-voltage power supply.

[0006] In a first aspect, the present invention provides a high-voltage power supply device with a wide voltage range output, the high-voltage power supply device comprising an interconnected high-voltage direct current structure and a closed-loop control structure; the high-voltage direct current structure comprises:

[0007] AC grid input module, used for outputting AC power;

[0008] A step-down module, wherein a first input end of the step-down module is connected to an output end of the AC power grid input module, and is used to rectify the AC power and reduce a DC voltage after rectification of the AC power;

[0009] A high-frequency inverter, wherein a first input terminal of the high-frequency inverter is connected to an output terminal of the step-down module, and is used to convert the stepped-down DC voltage into a high-frequency AC voltage;

[0010] A high-voltage transformer, the input end of which is connected to the output end of the high-frequency inverter, and is used to convert the high-frequency AC voltage into a high-voltage and high-frequency AC voltage;

[0011] A voltage doubling rectifier circuit, the input end of which is connected to the output end of the high-voltage transformer, and is used to rectify the high-voltage and high-frequency AC voltage into a high-voltage DC voltage;

[0012] The closed-loop control structure is used to perform feedback regulation on the high-voltage DC voltage output by the high-voltage DC structure.

[0013] In an optional implementation, the voltage reduction module includes at least one first relay;

[0014] The first relay is used to switch the three-phase AC power output by the AC power grid input module to a single-phase power grid input, so as to reduce the output voltage of the AC power grid input module.

[0015] In an optional implementation, the step-down module includes at least one autotransformer and at least one second relay;

[0016] The autotransformer is used to adjust the output voltage of the AC power grid input module through different winding turns ratios;

[0017] The second relay is used to switch the number of turns of the autotransformer to the number of turns of the target transformation ratio, so as to reduce the output voltage of the AC power grid input module.

[0018] In an optional implementation, the step-down module includes at least four thyristors and corresponding trigger circuits;

[0019] The trigger circuit is used to control the DC bus voltage by adjusting the conduction angle of the thyristor, so as to reduce the output voltage of the AC grid input module.

[0020] In an optional embodiment, the step-down module includes a power electronic step-down circuit;

[0021] The power electronic step-down circuit is used to reduce the DC side voltage by adjusting the duty cycle of the semiconductor switch, so as to perform step-down processing on the output voltage of the AC power grid input module.

[0022] In an optional implementation, the power electronic step-down circuit is a BUCK circuit.

[0023] In an optional implementation, the closed-loop control structure includes:

[0024] A high-voltage sampling module, the input end of which is connected to the output end of the voltage-doubling rectifier circuit, and is used to reduce the high-voltage DC voltage to a low-voltage DC voltage;

[0025] An operational amplifier conditioning module, the input end of which is connected to the output end of the high-voltage sampling module, and is used to step down and filter the low-voltage DC voltage;

[0026] A digital controller, wherein the input end of the digital controller is connected to the output end of the operational amplifier conditioning module, and the output end of the digital controller is connected to the second input end of the high-frequency inverter, and is used to control the frequency and duty cycle of the high-frequency inverter according to the output signal of the operational amplifier conditioning module, so as to feedback regulate the high-voltage DC voltage output by the high-voltage DC structure.

[0027] In an optional implementation, the closed-loop control structure further includes an ADC module; the input end of the ADC module is connected to the output end of the operational amplifier conditioning module, and the output end of the ADC module is connected to the input end of the digital controller;

[0028] The ADC module is used to convert the analog voltage signal output by the operational amplifier conditioning module into a digital signal and send it to the digital controller.

[0029] In a second aspect, the present invention provides a method for controlling a high-voltage power supply with a wide voltage range output, the method being applied to a high-voltage power supply device with a wide voltage range output as described above, the method comprising:

[0030] The output voltage and output current of the high voltage DC structure are obtained through a high voltage sampling module and an operational amplifier conditioning module;

[0031] Based on the output voltage and the output current, determining an equivalent load resistance of the high voltage direct current structure;

[0032] When the high voltage DC structure is unloaded and a target low voltage is to be output, the following steps are performed:

[0033] Start the step-down module to reduce the voltage of the DC bus;

[0034] Based on the PWM control signal, the switching frequency of the high-frequency inverter is adjusted to the highest frequency, the phase shift angle of the resonant converter in the high-frequency inverter is made 180° by phase shift control, and the output voltage of the high-voltage DC structure is adjusted by adjusting the dead time of the resonant converter.

[0035] In an optional implementation manner, when the high voltage direct current structure is not no-loaded, the following steps are performed:

[0036] Obtaining a feedback error between an output voltage of the high voltage direct current structure and a preset voltage value;

[0037] The frequency and duty cycle of the PWM control signal are adjusted based on the feedback error to adjust the output voltage of the high voltage DC structure.

[0038] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes a high-voltage power supply control method with a wide voltage range output according to the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0039] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute a high-voltage power supply control method with a wide voltage range output according to the first aspect or any corresponding embodiment thereof.

[0040] In a fifth aspect, the present invention provides a computer program product, comprising computer instructions for causing a computer to execute a method for controlling a high-voltage power supply with a wide voltage range output according to the first aspect or any corresponding embodiment thereof.

[0041] The technical solution provided by the present invention may include the following beneficial effects:

[0042] By adding a step-down module before the high-frequency inverter, the DC bus voltage is effectively reduced, creating conditions for achieving a wide voltage range output, so that the power supply can better adapt to the diverse needs for output voltage under different working conditions, especially when low voltage output is required. The present invention avoids simultaneous conduction of the tubes by accurately controlling the phase shift angle to 180°, reduces unnecessary energy transfer to the secondary side, and at the same time, adopts a dead zone fuzzy control method, which can flexibly adjust the dead zone time according to actual conditions, and further inhibits the conversion of full-bridge energy to the secondary side under no-load conditions. The combination of this control strategy effectively solves the problem that the traditional full-bridge resonant converter cannot output a lower voltage due to tiny energy transfer when no-load, so that the high-voltage power supply can maintain good performance under different load conditions, and realizes stable output with a wide voltage range and a wide load range, so that the minimum voltage of the high-voltage power supply no-load output is greatly reduced from about 5% of the rated voltage to 0.3% of the rated voltage, which greatly broadens the voltage output lower limit of the high-voltage power supply, so that it can meet more application scenarios with strict requirements for low voltage under no-load conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 is a structural schematic diagram of a high-voltage power supply device with a wide voltage range output according to an embodiment of the present invention;

[0045] Figure 2 is a schematic diagram of voltage reduction of a first relay of a voltage reduction module according to an embodiment of the present invention;

[0046] Figure 3 is a schematic diagram of voltage reduction of an autotransformer of a voltage reduction module according to an embodiment of the present invention;

[0047] Figure 4 is a schematic diagram of voltage reduction of a thyristor of a voltage reduction module according to an embodiment of the present invention;

[0048] Figure 5 is a voltage reduction schematic diagram of a power electronic voltage reduction circuit according to an embodiment of the present invention;

[0049] Figure 6 is a structural schematic diagram of a high frequency inverter according to an embodiment of the present invention;

[0050] Figure 7 is a flow chart of a high voltage power supply control method with wide voltage range output according to an embodiment of the present invention;

[0051] Figure 8 is a schematic diagram of a gain curve of an LCC resonant converter in a high frequency inverter according to an embodiment of the present invention;

[0052] Fig. 9 is a schematic diagram of gate drive waveforms of power devices and inverter output voltage in an LCC resonant converter according to an embodiment of the present invention;

[0053] Fig.10 is a flow chart of control steps taken when the power supply load is unloaded and a target low voltage is to be output according to an embodiment of the present invention;

[0054] Fig.11 is a flow chart of control steps taken when the power supply load is not no-load according to an embodiment of the present invention;

[0055] Fig.12 is a structural block diagram of a high voltage power supply control device with wide voltage range output according to an embodiment of the present invention;

[0056] Fig.13 It is a schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0058] In this embodiment, a high voltage power supply device with a wide voltage range output is provided. Figure 1 is a schematic structural diagram of a high voltage power supply device with a wide voltage range output according to an embodiment of the present invention. Figure 1 As shown, the high-voltage power supply device includes a high-voltage direct current structure and a closed-loop control structure connected to each other; the high-voltage direct current structure includes:

[0059] AC grid input module, used for outputting AC power;

[0060] A step-down module, wherein a first input terminal of the step-down module is connected to an output terminal of the AC power grid input module, and is used to rectify the AC power and reduce a DC voltage after rectification of the AC power;

[0061] A high-frequency inverter, a first input end of which is connected to the output end of the step-down module, and is used to convert the stepped-down DC voltage into a high-frequency AC voltage;

[0062] A high-voltage transformer, the input end of which is connected to the output end of the high-frequency inverter, and is used to convert the high-frequency AC voltage into a high-voltage and high-frequency AC voltage;

[0063] A voltage doubler rectifier circuit, the input end of which is connected to the output end of the high-voltage transformer, and is used to rectify the high-voltage and high-frequency AC voltage into a high-voltage DC voltage;

[0064] The closed-loop control structure is used to perform feedback regulation on the high-voltage DC voltage output by the high-voltage DC structure.

[0065] Furthermore, the AC grid input module is the starting point of the entire high-voltage power supply device, which is responsible for receiving electrical energy from the AC grid and outputting it in the form of AC power. The AC grid input module can be three-phase AC power or single-phase AC power. The step-down module is located after the AC grid input module. Its main function is to rectify the AC power, that is, to convert the AC power into DC power and reduce the DC voltage after rectification to a lower level. The step-down module of this embodiment uses certain technical means to reduce the DC voltage after rectification of the three-phase AC power or single-phase AC power, so that the power supply can output a smaller voltage value. The high-frequency inverter is connected after the step-down module, and its task is to convert the DC voltage after the step-down into a high-frequency AC voltage. This conversion is achieved by the electronic switch inside the inverter in the form of a high-frequency switch, and the purpose is to provide a suitable input voltage for the subsequent high-voltage transformer. The high-voltage transformer receives the high-frequency AC voltage output by the high-frequency inverter and converts it into a high-frequency AC voltage of a higher voltage level. The voltage doubler rectifier circuit is located after the high-voltage transformer. Its function is to rectify the high-voltage and high-frequency AC voltage into a high-voltage DC voltage. The voltage doubler rectifier circuit uses capacitors to store energy in each AC cycle and release it in the next cycle, thereby doubling the voltage and finally obtaining a stable high-voltage DC output. The closed-loop control structure is the control core of the high-voltage power supply device. It is responsible for real-time monitoring and adjustment of the high-voltage DC voltage output by the high-voltage DC structure to ensure the stability and accuracy of the output voltage. The closed-loop control structure works through a feedback mechanism, that is, measuring the actual output voltage and comparing it with the preset target voltage. The control signal is adjusted according to the difference to achieve precise control of the output voltage.

[0066] In an optional implementation, the step-down module includes at least one first relay;

[0067] The first relay is used to switch the three-phase AC power output by the AC power grid input module to a single-phase power grid input, so as to reduce the output voltage of the AC power grid input module.

[0068] Furthermore, the first relay is used to switch the three-phase AC power output by the AC grid input module to a single-phase grid input. By this switching, the output voltage of the AC grid input module can be reduced because the single-phase input usually has a lower voltage level than the three-phase input. Figure 2 The schematic diagram of the voltage reduction of the first relay of the voltage reduction module is shown. When the input is three-phase AC power, the input of the AC three-phase grid can be switched to a single-phase grid input through the relay. Figure 2As shown, when the first switch S1, the second switch S2, and the third switch S3 are closed, the DC voltage obtained by the uncontrolled rectification of the rectifier bridge is 2.34*U1, where U1 is the phase voltage value. When the first switch S1 is closed, the DC voltage obtained by the uncontrolled rectification of the rectifier bridge is 1.414*U1, thereby achieving voltage reduction.

[0069] In an optional embodiment, the step-down module includes at least one autotransformer and at least one second relay;

[0070] The autotransformer is used to adjust the output voltage of the AC grid input module through different winding turn ratios;

[0071] The second relay is used to switch the number of turns of the autotransformer to the number of turns of the target transformation ratio so as to reduce the output voltage of the AC power grid input module.

[0072] Furthermore, the autotransformer adjusts the output voltage of the AC grid input module through different winding turns ratios. Due to its structural characteristics, the autotransformer can achieve voltage up and down conversion more efficiently and at a relatively low cost. The second relay is used to switch the winding turns of the autotransformer to the winding turns of the target ratio to achieve the required voltage reduction effect. See Figure 3 The step-down schematic diagram of the autotransformer of the step-down module is shown, and the autotransformer has three windings, which are marked as N1, N2 and N3. The AC input voltage is Vin. When the fifth switch S5 is closed, the calculation formula of the output voltage Vout2 is Vout2 = Vin*(N2+N3). When the fourth switch S4 is closed, the calculation formula of the output voltage Vout2 is Vout2 = Vin*(N2), and the voltage is reduced. Therefore, when the fifth switch S5 is switched from closed to the fourth switch S4 is closed, the output voltage is reduced, and the step-down function is realized.

[0073] In an optional implementation, the buck module includes at least four thyristors and corresponding trigger circuits;

[0074] The trigger circuit is used to control the DC bus voltage by adjusting the conduction angle of the thyristor, so as to reduce the output voltage of the AC power grid input module.

[0075] Furthermore, the trigger circuit controls the DC bus voltage by adjusting the conduction angle of the thyristor, thereby reducing the output voltage of the AC grid input module. The thyristor is a semiconductor switching element, and the size of its conduction angle determines the current and voltage waveform passing through it, thereby affecting the size of the DC bus voltage. Figure 4The step-down schematic diagram of the thyristor of the step-down module is shown. In this embodiment, the thyristor rectifier current is used to control the voltage of the DC bus by adjusting the conduction angle α of the thyristor. The step-down module adopts a single-phase thyristor rectifier, and the connection method is as follows Figure 4 As shown, the thyristor (VT1-VT4) has unidirectional conductivity. When the thyristor receives enough trigger signals, it will change from the blocking state to the conducting state. In this embodiment, VT1-VT4 constitutes a single-phase bridge rectifier circuit. By adjusting the trigger angle α, the conduction time of the thyristor in each power frequency cycle can be changed, thereby controlling the rectified DC voltage. The thyristor is turned on by the trigger signal through the driver. The trigger angle α is defined as the ratio of the time interval t1 between the grid voltage and the zero crossing point when the thyristor starts to turn on to the power frequency cycle T, as shown in the following formula:

[0076]

[0077] At the trigger angle α, a trigger pulse is applied to the first thyristor VT1 and the fourth thyristor VT4. Even if the first thyristor VT1 and the fourth thyristor VT4 are turned on, the current flows through the first thyristor VT1 and the fourth thyristor VT4. When the grid voltage passes through zero, the current flowing through the first thyristor VT1 and the fourth thyristor VT4 will also drop to 0, and the first thyristor VT1 and the fourth thyristor VT4 are turned off.

[0078] In the negative half cycle of the grid voltage, the second thyristor VT2 and the third thyristor VT3 are still triggered at the trigger angle α, the second thyristor VT2 and the third thyristor VT3 are turned on, and the current flows from the negative pole of the grid through VT3 into the rectifier circuit, and then flows back to the positive pole of the grid through VT2.

[0079] When the trigger angle α is adjusted, the voltage of the DC bus can be adjusted. The relationship between the output DC bus voltage Udc and the trigger angle α is: Udc=0.9U1*(1+cosα) / 2; wherein U1 is the phase voltage value, that is, the effective value of the AC voltage.

[0080] In an optional embodiment, the step-down module includes a power electronic step-down circuit;

[0081] The power electronic step-down circuit is used to reduce the DC side voltage by adjusting the duty cycle of the semiconductor switch, so as to perform step-down processing on the output voltage of the AC power grid input module.

[0082] In an optional implementation, the power electronic step-down circuit is a BUCK circuit.

[0083] Furthermore, the power electronic buck circuit reduces the DC side voltage by adjusting the duty cycle of the semiconductor switch. The duty cycle refers to the ratio of the time the semiconductor switch is on in one cycle to the total cycle time. By adjusting the duty cycle, the output DC voltage can be controlled. The power electronic buck circuit is specifically a BUCK circuit. The BUCK circuit is a commonly used DC buck circuit that achieves precise control of the output voltage by adjusting the duty cycle of the switch element. See Figure 5 The schematic diagram of the voltage reduction of the power electronic buck circuit is shown in FIG. 1 . In this embodiment, the DC side voltage is reduced by the power electronic buck circuit, and the buck circuit can be used for voltage reduction. Figure 5 As shown, the output voltage Vdc can be adjusted by adjusting the semiconductor switch S, and the relationship between the output voltage Vdc and the DC voltage Vin is Vdc=Vin*D1. Where D1 is the duty cycle of the semiconductor switch S, L is the output inductor, C is the output DC capacitor, and D is the diode.

[0084] For further information, see Figure 6 The schematic diagram of the high frequency inverter is shown in FIG. Figure 6 Q1 to Q4 in the figure form a full-bridge inverter structure. The full-bridge inverter consists of four power devices (Q1 to Q4) that can convert the DC voltage input from the DC bus into AC voltage. Figure 1 As shown, the PWM signal generated by the digital controller controls the on and off of Q1 to Q4 through the driving circuit. When the first power device Q1 and the fourth power device Q4 are turned on at the same time, and the second power device Q2 and the third power device Q3 are turned off at the same time, the current flows from the positive electrode of the DC bus through the first power device Q1, the series resonant inductor Ls, the series resonant capacitor Cs, the resonant capacitor Cp, and the fourth power device Q4 back to the negative electrode of the DC bus, generating a forward voltage; when the second power device Q2 and the third power device Q3 are turned on at the same time, and the first power device Q1 and the fourth power device Q4 are turned off at the same time, the current flows in the reverse direction, generating a reverse voltage, thereby realizing an AC voltage output.

[0085] The high-frequency inverter includes an LCC resonant converter (including a series resonant inductor Ls, a series resonant capacitor Cs and a resonant capacitor Cp). The function of the LCC resonant converter is to make the AC voltage output by the high-frequency inverter reach a resonant state at a specific frequency, thereby improving the efficiency of power conversion. In the resonant state, the current and voltage waveforms in the circuit will reach an ideal sinusoidal state, reducing switching losses and electromagnetic interference. The high-voltage transformer boosts the high-frequency AC voltage processed by the LCC resonant converter and converts it into a high-voltage and high-frequency AC voltage. The voltage doubler rectifier circuit is used to rectify the high-voltage and high-frequency AC voltage output by the high-voltage transformer into a DC voltage. It realizes the rectification and boosting of the AC voltage through a combination of multiple diodes and capacitors to obtain the required DC output voltage.

[0086] In an optional implementation, the closed-loop control structure includes:

[0087] A high-voltage sampling module, the input end of which is connected to the output end of the voltage-doubling rectifier circuit, and is used to reduce the high-voltage DC voltage to a low-voltage DC voltage;

[0088] An operational amplifier conditioning module, the input end of which is connected to the output end of the high voltage sampling module, and is used to step down and filter the low voltage DC voltage;

[0089] A digital controller, the input end of the digital controller is connected to the output end of the operational amplifier conditioning module, and the output end of the digital controller is connected to the second input end of the high-frequency inverter, and is used to control the frequency and duty cycle of the high-frequency inverter according to the output signal of the operational amplifier conditioning module, so as to feedback regulate the high-voltage DC voltage output by the high-voltage DC structure.

[0090] Furthermore, the input end of the high-voltage sampling module is connected to the output end of the voltage doubler rectifier circuit, which is used to directly obtain the high-voltage DC voltage. Its main function is to reduce the high-voltage DC voltage to a low-voltage DC voltage so that the subsequent circuit can process it safely and effectively. The high-voltage sampling module may include a voltage divider circuit and a possible protection circuit to ensure that the circuit components are not damaged during the sampling process. The input end of the operational amplifier conditioning module is connected to the output end of the high-voltage sampling module to receive the low-voltage DC voltage that has been stepped down. The main task of the operational amplifier conditioning module is to further step down and filter this low-voltage DC voltage to eliminate noise and interference and improve the accuracy of the signal. The filtering process usually includes low-pass filtering to remove high-frequency noise.

[0091] The input of the digital controller is connected to the output of the op amp conditioning module to receive the conditioned voltage signal. The digital controller is the core of the closed-loop control structure. Based on the received voltage signal, it calculates the frequency and duty cycle that need to be adjusted through an internal algorithm. These adjustment instructions are then sent to the second input of the high-frequency inverter to achieve feedback regulation of the high-voltage DC voltage. The purpose of feedback regulation is to keep the high-voltage DC voltage within the set range and improve the stability and accuracy of the system.

[0092] In an optional implementation, the closed-loop control structure further includes an ADC module; the input end of the ADC module is connected to the output end of the operational amplifier conditioning module, and the output end of the ADC module is connected to the input end of the digital controller;

[0093] The ADC module is used to convert the analog voltage signal output by the operational amplifier conditioning module into a digital signal and send it to the digital controller.

[0094] Furthermore, the input end of the ADC module is connected to the output end of the op amp conditioning module to receive the analog voltage signal, and its function is to convert the analog voltage signal into a digital signal and then send it to the digital controller. The digital controller processes the digital signal, so the existence of the ADC module enables the system to read and process the voltage signal more accurately, thereby improving the control accuracy.

[0095] Furthermore, the high-voltage sampling module reduces the output high-voltage voltage to a low-voltage DC voltage that can be accepted by the op amp. The op amp conditioning module further reduces the voltage and filters the low-voltage DC voltage signal through the precision op amp and sends it to the ADC module. The ADC module converts the input analog voltage signal into a digital signal and sends it to the digital controller. The digital controller controls the frequency duty cycle of the high-frequency inverter through the output PWM control signal through the control algorithm, and the power electronic converter output forms a high-voltage output through the high-voltage transformer and voltage doubler rectification.

[0096] In summary, by adding a step-down module before the high-frequency inverter, the DC bus voltage is effectively reduced, creating conditions for achieving a wide voltage range output, so that the power supply can better adapt to the diverse needs for output voltage under different working conditions, especially when low voltage output is required. The present invention avoids simultaneous conduction of the tubes by accurately controlling the phase shift angle to 180°, reduces unnecessary energy transfer to the secondary side, and at the same time, adopts a dead zone fuzzy control method, which can flexibly adjust the dead zone time according to actual conditions, and further inhibits the conversion of full-bridge energy to the secondary side under no-load conditions. The combination of this control strategy effectively solves the problem that the traditional full-bridge resonant converter cannot output a lower voltage due to tiny energy transfer when no-load, so that the high-voltage power supply can maintain good performance under different load conditions, and realizes stable output with a wide voltage range and a wide load range, so that the minimum voltage of the high-voltage power supply no-load output is greatly reduced from about 5% of the rated voltage to 0.3% of the rated voltage, which greatly broadens the voltage output lower limit of the high-voltage power supply, so that it can meet more application scenarios with strict requirements for low voltage under no-load conditions.

[0097] According to an embodiment of the present invention, an embodiment of a high-voltage power supply control method with a wide voltage range output is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0098] In this embodiment, a high voltage power supply control method with a wide voltage range output is provided. Figure 1 In the high voltage power supply device with a wide voltage range output shown in FIG. Figure 7FIG. 1 is a flow chart of a high voltage power supply control method for outputting a wide voltage range according to an embodiment of the present invention. Figure 7 As shown, the process includes the following steps:

[0099] Step S701, obtaining the output voltage and output current of the high voltage DC structure through a high voltage sampling module and an operational amplifier conditioning module.

[0100] For further information, see Figure 8 The gain curve diagram of the LCC resonant converter in the high-frequency inverter is shown in FIG. 1 , where Vo / Vin is the system gain, and the normalized angular frequency is wn=2*π*fs, where fs is the switching frequency. The Q factor is a parameter that measures the balance between energy storage and loss in the resonant circuit, and the calculation formula is Among them, L s is the series resonant inductor, R o is the equivalent load resistance. The higher the Q factor, the greater the energy storage capacity of the circuit and the smaller the loss.

[0101] When the output impedance is only the sampling resistor, the equivalent load resistance R o The output impedance approaches infinity, which is equivalent to the Q factor approaching 0. At this time, the corresponding system gain will also be very large. When using conventional PFM control, the high-voltage power supply cannot output a lower voltage.

[0102] In order to reduce the output of the high-voltage power supply, the shift control can be used. When the fixed dead zone is used, in order to make the output 0, the shift angle needs to be controlled to 180°, and the two power devices of the tube will not be turned on at the same time. However, due to the slight error in the switching delay time of the two arms of the full bridge, the LCC resonant converter has energy storage elements, so under no-load conditions, a small amount of energy will still be transferred to the high-voltage side, causing the high-voltage power supply to be unable to output a lower voltage. Please refer to Fig. 9 The schematic diagram of the gate drive waveform of the power device and the inverter output voltage in the LCC resonant converter is shown, Vgs-Q1 is the drive waveform of the first power device Q1, Vgs-Q4 is the drive waveform of the fourth power device Q4, t1 is the rise time, t2 is the high level time, t3 is the fall time, Vint is the inverter output voltage, when the dead zone is small, the two drives have an overlapping time t4, resulting in the inverter still having a voltage output.

[0103] Furthermore, the high-voltage sampling module and the op amp conditioning module play a role in obtaining key data in the entire control process. The high-voltage sampling module first divides the high-voltage DC voltage finally output by the high-voltage DC structure to reduce it to a low-voltage DC voltage. This is because subsequent circuit components (such as op amps, etc.) are usually unable to directly process excessively high voltage signals. Then, the op amp conditioning module further steps down and filters this low-voltage DC voltage to remove possible stray signals such as noise and interference in the signal, thereby improving the quality and stability of the signal. At the same time, the output current information can also be indirectly obtained through relevant circuit principles. Through the collaborative work of these two modules, the output voltage and output current of the high-voltage DC structure can be accurately obtained, providing basic data support for subsequent judgment of the working status of the power supply and implementation of corresponding control strategies.

[0104] Step S702: determining an equivalent load resistance of the high voltage DC structure based on the output voltage and the output current.

[0105] Furthermore, after obtaining the output voltage and output current, the equivalent load resistance of the high-voltage DC structure can be calculated according to Ohm's law. The reason for judging the equivalent load resistance is that the working characteristics of the power supply under no-load and loaded conditions are very different, and different control strategies need to be adopted according to the load conditions to achieve a wide voltage range output and stable voltage regulation. By accurately judging the equivalent load resistance, it is clear whether the power supply is currently in a no-load state or a non-no-load state with an actual load connected, and then decide the specific control operation that should be performed next.

[0106] Step S703: when the high voltage DC structure is unloaded and is ready to output a target low voltage, the following steps are performed:

[0107] Start the step-down module to reduce the voltage of the DC bus;

[0108] Based on the PWM control signal, the switching frequency of the high-frequency inverter is adjusted to the highest frequency, the phase shift angle of the resonant converter in the high-frequency inverter is made 180° by phase shift control, and the output voltage of the high-voltage DC structure is adjusted by adjusting the dead time of the resonant converter.

[0109] Further, when it is determined that the high-voltage DC structure is unloaded and there is a need to output the target low voltage, the buck module is first started to reduce the voltage of the DC bus. There are many ways to implement the buck module, such as switching the three-phase AC power to single-phase power through a relay, using an autotransformer to switch to a winding with a small turns ratio, adjusting the conduction angle of the thyristor, or using a power electronic buck circuit (such as a BUCK circuit) to adjust the duty cycle. Reducing the DC bus voltage from the source can create favorable conditions for the subsequent low-voltage output and avoid the difficulty in achieving the target low voltage output requirement due to the initial voltage being too high. Adjusting the switching frequency of the high-frequency inverter to the highest frequency can reduce the inverter gain and reduce the amount of energy transferred to the secondary side, which helps to further reduce the output voltage under no-load conditions and make the output voltage approach the target low voltage. The phase shift control is adopted and the phase shift angle of the resonant converter in the high-frequency inverter is set to 180°, in order to avoid the simultaneous conduction of the tube (such as the upper and lower power devices in the full-bridge structure), which can maximize the prevention of unnecessary energy transmission to the high-voltage side, thereby better controlling the size of the output voltage and reducing it as much as possible. Although the phase shift angle is set to 180° in this embodiment, due to the slight error in the switching delay time of the two bridge arms of the full bridge in practice and the presence of energy storage elements in the resonant converter, a small amount of energy may still be transferred to the high voltage side when no-load, resulting in the inability to output a very low voltage. Therefore, it is necessary to accurately control the on- and off-time of the power device by adjusting the dead time of the resonant converter, suppress the tiny energy transfer caused by the error and the energy storage element, and further fine-tune the output voltage of the high-voltage DC structure so that it can meet the target low voltage requirements.

[0110] See also Fig.10The control steps flow chart shown in FIG. 1 shows the control steps taken when the power supply load is unloaded and the target low voltage is to be output. When the system is unloaded and a low voltage is to be output, the buck module is first started to reduce the DC bus voltage. In a high-frequency inverter, the switching frequency has an impact on the inverter gain. The inverter gain (k) is a parameter related to the inverter, which determines the proportional relationship between the inverter output voltage and the input voltage. In the full-bridge inverter structure, phase shift control is an important control method. When the phase shift angle is 180°, the tubes can theoretically not be turned on at the same time. This can minimize the unnecessary energy transferred to the high-voltage side. Because if the tubes are turned on at the same time, a large current will flow through the circuit, causing the output voltage to increase. By controlling the phase shift angle to 180°, this situation can be avoided to a large extent, which helps to control the reduction of the output voltage. Although the phase shift angle is set to 180°, in the actual circuit, due to the slight error in the switching delay time of the two arms of the full bridge and the presence of energy storage elements in the resonant converter, a small amount of energy may still be transferred to the high-voltage side when unloaded, resulting in the inability to output a very low voltage. Dead time refers to a time interval set in the control signal to avoid the upper and lower bridge arms from being turned on at the same time. By accurately adjusting the dead time, the on and off intervals of the power device can be further controlled, and the tiny energy transfer caused by the switch delay error and the energy storage element can be suppressed, thereby more finely adjusting the output voltage of the high-voltage DC structure to a lower level. Fig.10 As shown, in this embodiment, the voltage reference U2 is first set, and then adjusted by a digital controller (PID). The adjusted voltage is inverted and amplified by an inversion gain k, and then voltage conversion is performed according to the transformer ratio N, and then voltage multiplication rectification is performed by a voltage multiplication level m, and finally a high-voltage output U0 is obtained. At the same time, the high-voltage output U0 is fed back to the PID controller through the voltage division coefficient β to form a closed-loop control to ensure the stability and accuracy of the output voltage. The dead time is used to further accurately control the output voltage during the inversion process.

[0111] In some optional implementations, when the high voltage DC structure is not no-loaded, the following steps are performed:

[0112] Obtaining a feedback error between an output voltage of the high voltage direct current structure and a preset voltage value;

[0113] The frequency and duty cycle of the PWM control signal are adjusted based on the feedback error to adjust the output voltage of the high voltage DC structure.

[0114] Furthermore, when the high-voltage DC structure is not unloaded, the feedback error between the actual output voltage and the preset voltage value must first be obtained. This is achieved by transmitting the actual output voltage signal obtained by the high-voltage sampling module and the op amp conditioning module to the digital controller through the ADC module. The digital controller pre-sets the expected output voltage value (i.e., the preset voltage value), and then compares the received digital signal representing the actual output voltage with it to calculate the difference between the two. This difference is the feedback error. The digital controller uses the built-in control algorithm (such as the PID control algorithm, etc.) to adjust the frequency and duty cycle of the output PWM control signal based on the calculated feedback error. The PWM control signal acts on the high-frequency inverter, and by changing its frequency, it can affect the frequency characteristics of the high-frequency AC voltage output by the high-frequency inverter, while adjusting the duty cycle directly determines the length of the conduction time of the power device in each switching cycle, that is, it controls the amount of energy input to the high-frequency inverter. The high-frequency AC voltage output by the high-frequency inverter is boosted by the high-voltage transformer and rectified by the voltage doubler rectifier circuit, which ultimately affects the high-voltage DC output voltage. Therefore, by adjusting the frequency and duty cycle of the PWM control signal, the output voltage of the high-voltage DC structure can be accurately feedback-adjusted to make it approach the preset voltage value, ensuring that under different load conditions, the high-voltage power supply can output a stable and satisfactory voltage, achieving output characteristics with a wide voltage range and a wide load range.

[0115] See also Fig.11 The control steps flow chart shown in FIG. 1 shows the control steps taken when the power supply load is not no-load. First, the voltage reference U2 is set, and the digital controller (PID) is used for adjustment. The adjusted voltage is inverted and amplified through the inverter gain k, and then the voltage is converted according to the transformer ratio N, and then the voltage is doubled and rectified through the voltage multiplier level m, and finally the high-voltage output U0 is obtained. At the same time, the high-voltage output U0 is fed back to the digital controller (PID) through the voltage division coefficient β to form a closed-loop control to ensure the stability and accuracy of the output voltage.

[0116] In summary, by adding a step-down module before the high-frequency inverter, the DC bus voltage is effectively reduced, creating conditions for achieving a wide voltage range output, so that the power supply can better adapt to the diverse needs for output voltage under different working conditions, especially when low voltage output is required. The present invention avoids simultaneous conduction of the tubes by accurately controlling the phase shift angle to 180°, reduces unnecessary energy transfer to the secondary side, and at the same time, adopts a dead zone fuzzy control method, which can flexibly adjust the dead zone time according to actual conditions, and further inhibits the conversion of full-bridge energy to the secondary side under no-load conditions. The combination of this control strategy effectively solves the problem that the traditional full-bridge resonant converter cannot output a lower voltage due to tiny energy transfer when no-load, so that the high-voltage power supply can maintain good performance under different load conditions, and realizes stable output with a wide voltage range and a wide load range, so that the minimum voltage of the high-voltage power supply no-load output is greatly reduced from about 5% of the rated voltage to 0.3% of the rated voltage, which greatly broadens the voltage output lower limit of the high-voltage power supply, so that it can meet more application scenarios with strict requirements for low voltage under no-load conditions.

[0117] In this embodiment, a high voltage power supply control device with a wide voltage range output is also provided, which is used to implement the above-mentioned embodiments and preferred implementation modes, and the descriptions that have been made will not be repeated. As used below, the term "module" can implement a combination of software and / or hardware of a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0118] This embodiment provides a high voltage power supply control device with a wide voltage range output, such as Fig.12 As shown, including:

[0119] An output data acquisition module 1201 is used to acquire the output voltage and output current of the high voltage DC structure through a high voltage sampling module and an operational amplifier conditioning module;

[0120] A load resistance determination module 1202, configured to determine an equivalent load resistance of the high voltage DC structure based on the output voltage and the output current;

[0121] The output voltage regulating module 1203 is used to perform the following steps when the high-voltage DC structure is unloaded and the target low voltage is to be output: starting the step-down module to reduce the voltage of the DC bus; based on the PWM control signal, adjusting the switching frequency of the high-frequency inverter to the highest frequency, using phase shift control to make the phase shift angle of the resonant converter in the high-frequency inverter 180°, and adjusting the output voltage of the high-voltage DC structure by adjusting the dead time of the resonant converter.

[0122] In some optional embodiments, the output voltage regulation module 1203 is also used to perform the following steps when the high-voltage DC structure is not no-loaded: obtaining a feedback error between the output voltage of the high-voltage DC structure and a preset voltage value; and adjusting the frequency and duty cycle of the PWM control signal based on the feedback error to adjust the output voltage of the high-voltage DC structure.

[0123] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0124] See also Fig.13 , Fig.13 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Fig.13 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig.13 A processor 10 is taken as an example.

[0125] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0126] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0127] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0128] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0129] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0130] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor, or hardware, the method shown in the above embodiment is implemented.

[0131] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0132] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the defined scope.

Claims

1. A high voltage power supply device with a wide voltage range output, characterized in that: The high-voltage power supply device comprises a high-voltage direct current structure and a closed-loop control structure connected to each other; the high-voltage direct current structure comprises: AC grid input module, used for outputting AC power; A step-down module, wherein a first input end of the step-down module is connected to an output end of the AC power grid input module, and is used to rectify the AC power and reduce a DC voltage after rectification of the AC power; A high-frequency inverter, wherein a first input terminal of the high-frequency inverter is connected to an output terminal of the step-down module, and is used to convert the stepped-down DC voltage into a high-frequency AC voltage; A high-voltage transformer, the input end of which is connected to the output end of the high-frequency inverter, and is used to convert the high-frequency AC voltage into a high-voltage and high-frequency AC voltage; A voltage doubler rectifier circuit, the input end of which is connected to the output end of the high-voltage transformer, and is used to rectify the high-voltage and high-frequency AC voltage into a high-voltage DC voltage; The closed-loop control structure is used to perform feedback regulation on the high-voltage DC voltage output by the high-voltage DC structure.

2. The high voltage power supply device according to claim 1, characterized in that: The step-down module includes at least one first relay; The first relay is used to switch the three-phase AC power output by the AC power grid input module to a single-phase power grid input, so as to reduce the output voltage of the AC power grid input module.

3. The high voltage power supply device according to claim 1, characterized in that: The step-down module includes at least one autotransformer and at least one second relay; The autotransformer is used to adjust the output voltage of the AC power grid input module through different winding turns ratios; The second relay is used to switch the number of turns of the autotransformer to the number of turns of the target transformation ratio, so as to reduce the output voltage of the AC power grid input module.

4. The high voltage power supply device according to claim 1, characterized in that: The step-down module includes at least four thyristors and corresponding trigger circuits; The trigger circuit is used to control the DC bus voltage by adjusting the conduction angle of the thyristor, so as to reduce the output voltage of the AC grid input module.

5. The high voltage power supply device according to claim 1, characterized in that: The step-down module includes a power electronic step-down circuit; The power electronic step-down circuit is used to reduce the DC side voltage by adjusting the duty cycle of the semiconductor switch, so as to perform step-down processing on the output voltage of the AC power grid input module.

6. The high voltage power supply device according to claim 5, characterized in that: The power electronic step-down circuit is a BUCK circuit.

7. The high voltage power supply device according to claim 1, characterized in that: The closed-loop control structure comprises: A high-voltage sampling module, the input end of which is connected to the output end of the voltage-doubling rectifier circuit, and is used to reduce the high-voltage DC voltage to a low-voltage DC voltage; An operational amplifier conditioning module, the input end of which is connected to the output end of the high-voltage sampling module, and is used to step down and filter the low-voltage DC voltage; A digital controller, wherein the input end of the digital controller is connected to the output end of the operational amplifier conditioning module, and the output end of the digital controller is connected to the second input end of the high-frequency inverter, and is used to control the frequency and duty cycle of the high-frequency inverter according to the output signal of the operational amplifier conditioning module, so as to feedback regulate the high-voltage DC voltage output by the high-voltage DC structure.

8. The high voltage power supply device according to claim 7, characterized in that: The closed-loop control structure further includes an ADC module; the input end of the ADC module is connected to the output end of the operational amplifier conditioning module, and the output end of the ADC module is connected to the input end of the digital controller; The ADC module is used to convert the analog voltage signal output by the operational amplifier conditioning module into a digital signal and send it to the digital controller.

9. A method for controlling a high voltage power supply with a wide voltage range output, characterized in that: The method is applied to a high voltage power supply device with a wide voltage range output as claimed in any one of claims 1 to 8, and the method comprises: The output voltage and output current of the high voltage DC structure are obtained through a high voltage sampling module and an operational amplifier conditioning module; Based on the output voltage and the output current, determining an equivalent load resistance of the high voltage direct current structure; When the high voltage DC structure is unloaded and a target low voltage is to be output, the following steps are performed: Start the step-down module to reduce the voltage of the DC bus; Based on the PWM control signal, the switching frequency of the high-frequency inverter is adjusted to the highest frequency, the phase shift angle of the resonant converter in the high-frequency inverter is made 180° by phase shift control, and the output voltage of the high-voltage DC structure is adjusted by adjusting the dead time of the resonant converter.

10. The control method according to claim 9, characterized in that: When the high voltage direct current structure is not no-loaded, the following steps are performed: Obtaining a feedback error between an output voltage of the high voltage direct current structure and a preset voltage value; The frequency and duty cycle of the PWM control signal are adjusted based on the feedback error to adjust the output voltage of the high voltage DC structure.

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