Frequency conversion inversion control circuit and high voltage generator

Abstract

The utility model provides a frequency conversion inversion control circuit. An inversion assembly is connected with an input assembly, a frequency adjusting assembly and an output assembly. The frequency adjusting assembly is connected with the output assembly; the output voltage of the input assembly is transmitted to the inversion assembly; the inversion voltage of the inversion assembly is transmitted to the output assembly; a current feedback signal of the inversion assembly is transmitted to the frequency adjusting assembly; a voltage feedback signal of the output assembly is transmitted to the frequency adjusting assembly; an inversion driving signal of the frequency adjusting assembly is transmitted to the inversion assembly. The inverter control circuit solves the technical problems that an existing inverter control circuit cannot meet the requirement for wide-range power output, and the conversion efficiency is insufficient in the high-power state, and the technical effects of improving the conversion efficiency and stabilizing high-power output are achieved.

Description

Technical Field

[0001] This application relates to the field of power supply circuits, and in particular to a frequency converter control circuit and a high voltage generator. Background Technology

[0002] With the development of medical imaging technology, medical X-ray machines have become essential imaging diagnostic equipment in hospitals. As the core power supply component of the X-ray machine imaging system, the efficiency and stability of the inverter are extremely important.

[0003] The inverter control circuit of a high-frequency high-voltage generator typically uses fixed-frequency PWM control technology. However, existing inverter control circuits cannot adapt to the demand for a wide range of power outputs, and their conversion efficiency is insufficient at high power. Utility Model Content

[0004] In view of the above problems, this application is made to provide a frequency converter control circuit and a high-voltage generator that overcomes or at least partially solves the above problems, comprising:

[0005] A variable frequency inverter control circuit includes: an input component, an inverter component, a frequency regulation component, and an output component;

[0006] The inverter component is connected to the input component, the frequency adjustment component, and the output component respectively; the frequency adjustment component is connected to the output component.

[0007] The output voltage of the input component is transmitted to the inverter component; the inverter voltage of the inverter component is transmitted to the output component; the current feedback signal of the inverter component is transmitted to the frequency adjustment component; the voltage feedback signal of the output component is transmitted to the frequency adjustment component; and the inverter drive signal of the frequency adjustment component is transmitted to the inverter component.

[0008] Furthermore, it includes: a voltage control unit, a current control unit, a triangular wave oscillation unit, and a drive unit;

[0009] The voltage control unit is connected to the current control unit and the output component respectively; the inverter component is connected to the current control unit, the triangular wave oscillation unit and the drive unit respectively; the drive unit is connected to the current control unit and the triangular wave oscillation unit respectively.

[0010] A preset reference voltage and the voltage feedback signal are input to the voltage control unit; the current feedback signal and the voltage error signal of the voltage control unit are input to the current control unit; the current sampling signal of the inverter component is transmitted to the triangular wave oscillation unit; the output signal of the current control unit and the triangular wave signal of the triangular wave oscillation unit are transmitted to the drive unit; the inverter drive signal of the drive unit is transmitted to the inverter component.

[0011] Furthermore, the voltage control unit includes: operational amplifier U1A and operational amplifier U1B;

[0012] The inverting input terminal of the operational amplifier U1A is connected to one end of resistor R3 and one end of resistor R6; the other end of resistor R3 is connected to one end of resistor R1.

[0013] The non-inverting input terminal of the operational amplifier U1A is connected to one end of the resistor R5; the other end of the resistor R5 is grounded.

[0014] The output terminal of the operational amplifier U1A is connected to the other end of resistor R6 and one end of resistor R8; the other end of resistor R8 is connected to one end of resistor R12.

[0015] The inverting input terminal of the operational amplifier U1B is connected to the positive terminal of diode D7, one end of resistor R14, one end of resistor R9, and the other end of resistor R12; the other end of resistor R14 is connected to one end of capacitor C6; and the other end of resistor R9 is connected to the output component.

[0016] The non-inverting input terminal of the operational amplifier U1B is connected to one end of the resistor R13; the other end of the resistor R13 is grounded.

[0017] The output terminal of the operational amplifier U1B is connected to the negative terminal of diode D7, the other end of capacitor C6, and one end of resistor R15; the other end of resistor R15 is connected to the input terminal of the current control unit.

[0018] The preset reference voltage is input to the other end of the resistor R1; the voltage feedback signal is input to the other end of the resistor R9.

[0019] Furthermore, the current control unit includes: an operational amplifier U2A and a current transformer T1;

[0020] The input terminal of the current transformer T1 is connected to the inverter assembly;

[0021] The first output terminal of the current transformer T1 is connected to the positive terminal of diode D10 and the negative terminal of diode D12.

[0022] The second output terminal of the current transformer T1 is connected to one end of the capacitor C21; the other end of the capacitor C21 is connected to the positive terminal of diode D11 and the negative terminal of diode D13; the positive terminals of diode D12 and diode D13 are grounded.

[0023] The non-inverting input terminal of the operational amplifier U2A is connected to one end of the resistor R31; the other end of the resistor R31 is connected to the voltage control unit.

[0024] The inverting input terminal of the operational amplifier U2A is connected to the positive terminal of diode D9, one end of capacitor C11, one end of resistor R27, one end of resistor R29, and one end of resistor R30; the other end of resistor R29 is connected to one end of capacitor C12; the other end of capacitor C12 is connected to the other end of resistor R30, the negative terminal of diode D10, and the negative terminal of diode D11.

[0025] The output terminal of the operational amplifier U2A is connected to the negative terminal of diode D9, the other end of capacitor C11, the other end of resistor R27, and the driving unit.

[0026] Furthermore, the output terminal of the operational amplifier U2A is connected to the driving unit through the operational amplifier U2B;

[0027] The output terminal of the operational amplifier U2A is connected to the positive terminal of the diode D8;

[0028] The non-inverting input of the operational amplifier U2B is connected to one end of resistor R21 and one end of resistor R24; the other end of resistor R21 is grounded; and the other end of resistor R24 ​​is connected to the negative terminal of diode D8.

[0029] The inverting input terminal of the operational amplifier U2B is connected to one end of resistor R7 and one end of resistor R19; the other end of resistor R7 is grounded.

[0030] The output terminal of the operational amplifier U2B is connected to the other end of the resistor R19 and the driving unit.

[0031] Furthermore, the triangular wave oscillation unit includes: a current transformer T2, a comparator U4, a comparator U5, a NAND gate U6, and a MOSFET Q3;

[0032] The input terminal of the current transformer T2 is connected to the inverter assembly; the first output terminal of the current transformer T2 is connected to one end of the resistor R40 and one end of the inductor L1; the second output terminal of the current transformer T2 is grounded.

[0033] The non-inverting input terminal of the comparator U4 is connected to the other end of resistor R40 and one end of resistor R38;

[0034] The inverting input of comparator U4 is connected to one end of resistor R39; the other end of resistor R39 is grounded.

[0035] The first complementary output of the comparator U4 is connected to the other end of the resistor R38 and pin 2B of the NAND gate U6.

[0036] The second complementary output of the comparator U4 is connected to pin 1A of the NAND gate U6;

[0037] The non-inverting input terminal of the comparator U5 is connected to one end of resistor R43 and one end of resistor R44; the other end of resistor R44 is connected to one end of resistor R46 and the other end of inductor L1.

[0038] The inverting input of comparator U5 is connected to one end of resistor R45; the other end of resistor R45 is connected to the other end of resistor R46 and ground.

[0039] The first complementary output terminal of the comparator U5 is connected to the other end of the resistor R43 and pin 1B of the NAND gate U6.

[0040] The second complementary output terminal of the comparator U5 is connected to pin 2A of the NAND gate U6 and the driving unit;

[0041] The NAND gate U6 is connected to the driving unit via MOS transistor Q3.

[0042] Furthermore, the 1Y pin of the NAND gate U6 is connected to the 3A pin of the NAND gate U6 and the driving unit; the 2Y pin of the NAND gate U6 is connected to the 3B pin of the NAND gate U6 and the driving unit; and the 3Y pin of the NAND gate U6 is connected to one end of the resistor R37.

[0043] The gate of the MOS transistor Q3 is connected to one end of resistor R36 and the other end of resistor R37.

[0044] The source of the MOSFET Q3 is connected to one end of the capacitor C15, the positive terminal of the Zener diode DZ4, the other end of the resistor R36, and the ground wire.

[0045] The drain of the MOS transistor Q3 is connected to the other end of the capacitor C15, the cathode of the Zener diode DZ4, and the driving unit.

[0046] Furthermore, the driving unit includes: comparator U3, flip-flop U7, driver U8, MOSFET Q2, MOSFET Q4, MOSFET Q5 and MOSFET Q6;

[0047] The inverting input of the comparator U3 is connected to one end of the resistor R17; the other end of the resistor R17 is connected to the current control unit.

[0048] The non-inverting input of the comparator U3 is connected to one end of the resistor R18; the other end of the resistor R18 is connected to one end of the resistor R16 and the triangular wave oscillation unit.

[0049] The output of the comparator U3 is connected to the other end of the resistor R16 and the CLK pin of the flip-flop U7;

[0050] The triangular wave oscillation unit is connected to the CLR pin, PRE pin and D pin of the trigger U7 respectively;

[0051] The first input terminal of the driver U8 is connected to the first Q pin of the flip-flop U7; the second input terminal of the driver U8 is connected to the second Q pin of the flip-flop U7.

[0052] The first output terminal of the driver U8 is connected to the anode of diode D14, the cathode of diode D15, one end of resistor R33, and one end of resistor R34; the gate of the MOSFET Q2 is connected to the cathode of diode D14 and the other end of resistor R33; the source of the MOSFET Q2 is connected to one end of capacitor C14 and the +12V power supply; the gate of the MOSFET Q4 is connected to the anode of diode D15 and the other end of resistor R34; the source of the MOSFET Q4 is connected to the other end of capacitor C14 and ground.

[0053] The second output terminal of the driver U8 is connected to the anode of diode D16, the cathode of diode D17, one end of resistor R41, and one end of resistor R42; the gate of the MOSFET Q5 is connected to the cathode of diode D16 and the other end of resistor R41; the source of the MOSFET Q5 is connected to one end of capacitor C23 and the +12V power supply; the gate of the MOSFET Q4 is connected to the anode of diode D17 and the other end of resistor R42; the source of the MOSFET Q4 is connected to the other end of capacitor C23 and ground.

[0054] The first input terminal of transformer T3 is connected to the drain of MOSFET Q2 and the drain of MOSFET Q4; the second input terminal of transformer T3 is connected to one end of capacitor C22; the other end of capacitor C22 is connected to the drain of MOSFET Q5 and the drain of MOSFET Q6; the output terminal of transformer T3 is connected to the inverter assembly.

[0055] Furthermore, the input component includes a rectifier unit and a filter unit; the filter unit is connected to both the rectifier unit and the inverter component; the power supply current is input to the filter unit; the filtered current of the filter unit is transmitted to the rectifier unit; and the rectified current of the rectifier unit is input to the inverter component.

[0056] A high-voltage generator includes the aforementioned frequency converter control circuit.

[0057] This application has the following advantages:

[0058] In the embodiments of this application, addressing the limitations of existing inverter control circuits in adapting to a wide range of power output requirements and insufficient conversion efficiency at high power, this application provides a solution employing frequency conversion control technology and using dual closed-loop control with KV feedback and inverter current feedback to adjust the inverter frequency and stabilize high power output. Specifically, a frequency conversion inverter control circuit is provided, wherein the inverter component is connected to an input component, a frequency adjustment component, and an output component; the frequency adjustment component is connected to the output component; the output voltage of the input component is transmitted to the inverter component; the inverter voltage of the inverter component is transmitted to the output component; the current feedback signal of the inverter component is transmitted to the frequency adjustment component; the voltage feedback signal of the output component is transmitted to the frequency adjustment component; and the inverter drive signal of the frequency adjustment component is transmitted to the inverter component. By using dual closed-loop control with KV feedback and inverter current feedback to adjust the inverter frequency and stabilize high power output, this solution addresses the technical problems of existing inverter control circuits being unable to adapt to a wide range of power output requirements and insufficient conversion efficiency at high power, achieving the technical effects of improved conversion efficiency and stable high power output. Attached Figure Description

[0059] To more clearly illustrate the technical solution of this application, the drawings used in the description of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This is a first structural block diagram of a frequency converter control circuit provided in one embodiment of this application;

[0061] Figure 2 This is a second structural block diagram of a frequency converter control circuit provided in one embodiment of this application;

[0062] Figure 3 This is an overall circuit structure diagram of a frequency converter control circuit provided in one embodiment of this application;

[0063] Figure 4This is a partial circuit diagram illustrating the circuit structure of the voltage control unit in one embodiment of this application;

[0064] Figure 5 This is a partial circuit diagram illustrating the circuit structure of the current control unit in one embodiment of this application;

[0065] Figure 6 This is a partial circuit diagram illustrating the triangular wave oscillation unit circuit structure in one embodiment of this application;

[0066] Figure 7 This is a partial circuit diagram illustrating the driving unit circuit structure in one embodiment of this application;

[0067] Figure 8 This is a schematic diagram of the working principle of a high-voltage generator provided in one embodiment of this application. Detailed Implementation

[0068] To make the objectives, features, and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0069] The inventors, through analysis of existing technologies, discovered that: because the switching frequency of PWM control technology is fixed, fixed-frequency PWM pulse width modulation technology is difficult to improve the output power of high-frequency voltage regulator generators. The fixed switching frequency results in significant switching losses at high power levels, and MOSFETs are prone to overheating and damage under prolonged loads, thus failing to meet the demands of a wide range of power outputs and hindering the improvement of conversion efficiency at high power levels. Furthermore, some frequency converter control circuits typically employ single-loop control for feedback regulation, which usually only adjusts a single parameter (such as voltage). Even under complex system operating conditions, it remains difficult to ensure the stability of output control.

[0070] Based on the above analysis, one of the core technical concepts of this application is to adopt variable frequency soft-switching full-bridge inverter control technology and to adjust the inverter frequency through dual closed-loop control of KV feedback and inverter current feedback to stabilize high power output.

[0071] Reference Figure 1 This illustration shows a frequency converter control circuit according to an embodiment of the present application, including: an input component, an inverter component, a frequency adjustment component, and an output component;

[0072] The inverter component is connected to the input component, the frequency adjustment component, and the output component respectively; the frequency adjustment component is connected to the output component.

[0073] The output voltage of the input component is transmitted to the inverter component; the inverter voltage of the inverter component is transmitted to the output component; the current feedback signal of the inverter component is transmitted to the frequency adjustment component; the voltage feedback signal of the output component is transmitted to the frequency adjustment component; and the inverter drive signal of the frequency adjustment component is transmitted to the inverter component.

[0074] In the embodiments of this application, addressing the limitations of existing inverter control circuits in adapting to a wide range of power output requirements and insufficient conversion efficiency at high power, this application provides a solution employing frequency conversion control technology and using dual closed-loop control with KV feedback and inverter current feedback to adjust the inverter frequency and stabilize high power output. Specifically, a frequency conversion inverter control circuit is provided, wherein the inverter component is connected to an input component, a frequency adjustment component, and an output component; the frequency adjustment component is connected to the output component; the output voltage of the input component is transmitted to the inverter component; the inverter voltage of the inverter component is transmitted to the output component; the current feedback signal of the inverter component is transmitted to the frequency adjustment component; the voltage feedback signal of the output component is transmitted to the frequency adjustment component; and the inverter drive signal of the frequency adjustment component is transmitted to the inverter component. By using dual closed-loop control with KV feedback and inverter current feedback to adjust the inverter frequency and stabilize high power output, this solution addresses the technical problems of existing inverter control circuits being unable to adapt to a wide range of power output requirements and insufficient conversion efficiency at high power, achieving the technical effects of improved conversion efficiency and stable high power output.

[0075] The following will further describe a frequency converter control circuit in this exemplary embodiment.

[0076] It should be noted that the frequency adjustment component receives the current feedback signal from the inverter component and the voltage feedback signal from the output component, and adjusts and changes the inverter frequency through dual closed-loop feedback control, thereby stabilizing the high power output of the output component.

[0077] This application employs frequency conversion control technology. When power increases, the switching frequency decreases, reducing switching losses at high power levels and preventing damage to the MOSFETs due to excessive heat generation. Conversely, when power decreases, the switching frequency increases, resulting in lower output voltage ripple. Therefore, the switching frequency changes with power, reducing losses and heat generation in the power switching transistors during high-frequency switching, thereby improving the inverter's conversion efficiency. This satisfies both the requirements for higher frequency and lower ripple, as well as the demands for high-power output.

[0078] Reference Figure 2 In one embodiment of this application, it includes: a voltage control unit, a current control unit, a triangular wave oscillation unit, and a driving unit;

[0079] The voltage control unit is connected to the current control unit and the output component respectively; the inverter component is connected to the current control unit, the triangular wave oscillation unit and the drive unit respectively; the drive unit is connected to the current control unit and the triangular wave oscillation unit respectively.

[0080] A preset reference voltage and the voltage feedback signal are input to the voltage control unit; the current feedback signal and the voltage error signal of the voltage control unit are input to the current control unit; the current sampling signal of the inverter component is transmitted to the triangular wave oscillation unit; the output signal of the current control unit and the triangular wave signal of the triangular wave oscillation unit are transmitted to the drive unit; the inverter drive signal of the drive unit is transmitted to the inverter component.

[0081] It should be noted that the embodiments of this application include a voltage control loop and a current control loop, with voltage regulation feedback as the outer loop control and current regulation feedback as the inner loop control.

[0082] In the voltage control loop, the voltage control unit performs error integration on the preset reference voltage and the voltage feedback signal to obtain the voltage error signal; where kVSet is the preset reference voltage, and 1V can correspond to a kV value of 20KV; kVFB is the voltage feedback signal, which can also correspond to a kV value of 20KV; and kVout is the voltage error signal.

[0083] In the current control loop, the current control unit differentially amplifies and outputs the voltage error signal and the current sampling signal. The output signal of the current control unit serves as the regulating voltage of the entire frequency conversion control system, and performs frequency control for different output powers. Here, I_FB is the current feedback signal; INV_FB is the current sampling signal.

[0084] By sampling the inverter current, the feedback value of the inverter current is used in the error calculation of the current controller. On the other hand, the sampling waveform of the inverter current forms a triangular wave oscillator to collect the current frequency of the inverter current in real time. The output signal of the current controller is then compared with the triangular wave output by the triangular wave oscillator to obtain the clock signal of the inverter frequency at the next moment. This gives the inverter drive signal, which drives the inverter to switch according to the frequency of the drive signal, and adjusts the output high voltage to make it stably output according to the KV reference voltage.

[0085] Figure 2 The corresponding specific circuit structure diagram is as follows: Figure 3 As shown, understandably Figures 4-7 yes Figure 3 The corresponding local circuit diagram.

[0086] Reference Figure 4In one embodiment of this application, the voltage control unit includes: operational amplifier U1A and operational amplifier U1B;

[0087] The inverting input terminal of the operational amplifier U1A is connected to one end of resistor R3 and one end of resistor R6; the other end of resistor R3 is connected to one end of resistor R1.

[0088] The non-inverting input terminal of the operational amplifier U1A is connected to one end of the resistor R5; the other end of the resistor R5 is grounded.

[0089] The output terminal of the operational amplifier U1A is connected to the other end of resistor R6 and one end of resistor R8; the other end of resistor R8 is connected to one end of resistor R12.

[0090] The inverting input terminal of the operational amplifier U1B is connected to the positive terminal of diode D7, one end of resistor R14, one end of resistor R9, and the other end of resistor R12; the other end of resistor R14 is connected to one end of capacitor C6; and the other end of resistor R9 is connected to the output component.

[0091] The non-inverting input terminal of the operational amplifier U1B is connected to one end of the resistor R13; the other end of the resistor R13 is grounded.

[0092] The output terminal of the operational amplifier U1B is connected to the negative terminal of diode D7, the other end of capacitor C6, and one end of resistor R15; the other end of resistor R15 is connected to the input terminal of the current control unit.

[0093] The preset reference voltage is input to the other end of the resistor R1; the voltage feedback signal is input to the other end of the resistor R9.

[0094] It should be noted that the voltage control unit forms an outer-loop voltage regulation circuit through operational amplifier U1A and an inner-loop current regulation circuit through operational amplifier U1B, and outputs the integral signal kVout of the voltage error. Figure 4 The / KV_EN signal is the enable signal. When it is low, the kVset signal is valid and the circuit starts working.

[0095] Reference Figure 5 In one embodiment of this application, the current control unit includes: an operational amplifier U2A and a current transformer T1;

[0096] The input terminal of the current transformer T1 is connected to the inverter assembly;

[0097] The first output terminal of the current transformer T1 is connected to the positive terminal of diode D10 and the negative terminal of diode D12.

[0098] The second output terminal of the current transformer T1 is connected to one end of the capacitor C21; the other end of the capacitor C21 is connected to the positive terminal of diode D11 and the negative terminal of diode D13; the positive terminals of diode D12 and diode D13 are grounded.

[0099] The non-inverting input terminal of the operational amplifier U2A is connected to one end of the resistor R31; the other end of the resistor R31 is connected to the voltage control unit.

[0100] The inverting input terminal of the operational amplifier U2A is connected to the positive terminal of diode D9, one end of capacitor C11, one end of resistor R27, one end of resistor R29, and one end of resistor R30; the other end of resistor R29 is connected to one end of capacitor C12; the other end of capacitor C12 is connected to the other end of resistor R30, the negative terminal of diode D10, and the negative terminal of diode D11.

[0101] The output terminal of the operational amplifier U2A is connected to the negative terminal of diode D9, the other end of capacitor C11, the other end of resistor R27, and the driving unit.

[0102] It should be noted that the current sampling signal INV_FB of the inverter component is rectified by the current transformer T1 to obtain the current feedback signal I_FB; the voltage error signal kVout of the voltage control unit is input to the current control unit through resistor R31; and the output signal Iout is obtained through operational amplifier U2A. The output terminal of operational amplifier U2A can be connected to the drive unit through operational amplifier U2B.

[0103] The current control unit uses the kVout signal as the set value of the current control loop. When the high-frequency high-voltage generator is working normally, the value of the I_FB signal is positive.

[0104] Reference Figure 7 In one embodiment of this application, the output terminal of the operational amplifier U2A is connected to the driving unit through the operational amplifier U2B;

[0105] The output terminal of the operational amplifier U2A is connected to the positive terminal of the diode D8;

[0106] The non-inverting input of the operational amplifier U2B is connected to one end of resistor R21 and one end of resistor R24; the other end of resistor R21 is grounded; and the other end of resistor R24 ​​is connected to the negative terminal of diode D8.

[0107] The inverting input terminal of the operational amplifier U2B is connected to one end of resistor R7 and one end of resistor R19; the other end of resistor R7 is grounded.

[0108] The output terminal of the operational amplifier U2B is connected to the other end of the resistor R19 and the driving unit.

[0109] It should be noted that the output signal F_CON of the operational amplifier U2B can be input to the comparator U3 of the drive unit. After differential amplification, the I_FB signal and the kVout signal are used to obtain the frequency adjustment signal F_CON, which is used as the comparison level with the triangular wave signal.

[0110] Reference Figure 6 In one embodiment of this application, the triangular wave oscillation unit includes: a current transformer T2, a comparator U4, a comparator U5, a NAND gate U6, and a MOSFET Q3;

[0111] The input terminal of the current transformer T2 is connected to the inverter assembly; the first output terminal of the current transformer T2 is connected to one end of the resistor R40 and one end of the inductor L1; the second output terminal of the current transformer T2 is grounded.

[0112] The non-inverting input terminal of the comparator U4 is connected to the other end of resistor R40 and one end of resistor R38;

[0113] The inverting input of comparator U4 is connected to one end of resistor R39; the other end of resistor R39 is grounded.

[0114] The first complementary output of the comparator U4 is connected to the other end of the resistor R38 and pin 2B of the NAND gate U6.

[0115] The second complementary output of the comparator U4 is connected to pin 1A of the NAND gate U6;

[0116] The non-inverting input terminal of the comparator U5 is connected to one end of resistor R43 and one end of resistor R44; the other end of resistor R44 is connected to one end of resistor R46 and the other end of inductor L1.

[0117] The inverting input of comparator U5 is connected to one end of resistor R45; the other end of resistor R45 is connected to the other end of resistor R46 and ground.

[0118] The first complementary output terminal of the comparator U5 is connected to the other end of the resistor R43 and pin 1B of the NAND gate U6.

[0119] The second complementary output terminal of the comparator U5 is connected to pin 2A of the NAND gate U6 and the driving unit;

[0120] The NAND gate U6 is connected to the driving unit via MOS transistor Q3.

[0121] It should be noted that the triangular wave signal from the triangular wave oscillation unit can be input to comparator U3 of the drive unit. The current sampling signal INV_FB of the inverter component flows through inductor L1 and resistor R46 after passing through current transformer T2, generating two AC signals with a phase difference at the non-inverting input terminals of comparators U4 and U5. The frequency of this signal is consistent with the switching frequency of the inverter. Comparators U4 and U5 can be two high-speed zero-crossing comparators, which can convert the input AC signal into two pairs of complementary square wave signals respectively.

[0122] Reference Figure 6 In one embodiment of this application, the 1Y pin of the NAND gate U6 is connected to the 3A pin of the NAND gate U6 and the driving unit; the 2Y pin of the NAND gate U6 is connected to the 3B pin of the NAND gate U6 and the driving unit; and the 3Y pin of the NAND gate U6 is connected to one end of the resistor R37.

[0123] The gate of the MOS transistor Q3 is connected to one end of resistor R36 and the other end of resistor R37.

[0124] The source of the MOSFET Q3 is connected to one end of the capacitor C15, the positive terminal of the Zener diode DZ4, the other end of the resistor R36, and the ground wire.

[0125] The drain of the MOS transistor Q3 is connected to the other end of the capacitor C15, the cathode of the Zener diode DZ4, and the driving unit.

[0126] It should be noted that the two pairs of complementary square wave signals can be passed through three three-input NAND gates U6 to obtain a square wave drive signal with twice the inverter frequency. This square wave drive signal can be used to control the on and off of MOSFET Q3, thereby controlling the charging and discharging of capacitor C15 and generating a frequency-modulated triangular wave.

[0127] Reference Figure 7 In one embodiment of this application, the driving unit includes: comparator U3, flip-flop U7, driver U8, MOSFET Q2, MOSFET Q4, MOSFET Q5 and MOSFET Q6;

[0128] The inverting input of the comparator U3 is connected to one end of the resistor R17; the other end of the resistor R17 is connected to the current control unit.

[0129] The non-inverting input of the comparator U3 is connected to one end of the resistor R18; the other end of the resistor R18 is connected to one end of the resistor R16 and the triangular wave oscillation unit.

[0130] The output of the comparator U3 is connected to the other end of the resistor R16 and the CLK pin of the flip-flop U7;

[0131] The triangular wave oscillation unit is connected to the CLR pin, PRE pin and D pin of the trigger U7 respectively;

[0132] The first input terminal of the driver U8 is connected to the first Q pin of the flip-flop U7; the second input terminal of the driver U8 is connected to the second Q pin of the flip-flop U7.

[0133] The first output terminal of the driver U8 is connected to the anode of diode D14, the cathode of diode D15, one end of resistor R33, and one end of resistor R34; the gate of the MOSFET Q2 is connected to the cathode of diode D14 and the other end of resistor R33; the source of the MOSFET Q2 is connected to one end of capacitor C14 and the +12V power supply; the gate of the MOSFET Q4 is connected to the anode of diode D15 and the other end of resistor R34; the source of the MOSFET Q4 is connected to the other end of capacitor C14 and ground.

[0134] The second output terminal of the driver U8 is connected to the anode of diode D16, the cathode of diode D17, one end of resistor R41, and one end of resistor R42; the gate of the MOSFET Q5 is connected to the cathode of diode D16 and the other end of resistor R41; the source of the MOSFET Q5 is connected to one end of capacitor C23 and the +12V power supply; the gate of the MOSFET Q4 is connected to the anode of diode D17 and the other end of resistor R42; the source of the MOSFET Q4 is connected to the other end of capacitor C23 and ground.

[0135] The first input terminal of transformer T3 is connected to the drain of MOSFET Q2 and the drain of MOSFET Q4; the second input terminal of transformer T3 is connected to one end of capacitor C22; the other end of capacitor C22 is connected to the drain of MOSFET Q5 and the drain of MOSFET Q6; the output terminal of transformer T3 is connected to the inverter assembly.

[0136] It should be noted that the frequency adjustment signal F_CON of the control system is compared by comparator U3. The output signal of comparator U3 is output as a pair of complementary square wave signals after passing through flip-flop U7. After being amplified by driver U8, the signal drives the full-bridge diode drive circuit composed of MOSFETs Q2, Q4, Q5 and Q6 to output a square wave signal. The signal is then isolated and transformed by pulse transformer T3 to drive the inverter component.

[0137] As an example, after the transformer T3 is isolated and transformed, four isolated inverter drive signals DR1, DR2, DR3, and DR4 can be obtained. These four isolated drive signals directly drive the four bridge arms of the inverter to perform AC conversion on the DC bus voltage. Figure 7The DR_EN signal is the drive enable signal. When it is high, it enables the drive output. When it is low, it simultaneously locks the outputs of U6 and U8, thereby turning off the drive output and stopping the inverter from working. It mainly serves as a protection function when the system is abnormal.

[0138] In one embodiment of this application, the input component includes a rectifier unit and a filter unit; the filter unit is connected to both the rectifier unit and the inverter component; power supply current is input to the filter unit; the filtered current of the filter unit is transmitted to the rectifier unit; and the rectified current of the rectifier unit is input to the inverter component.

[0139] In one embodiment of this application, the frequency converter control circuit includes a control component, which is used to send a set voltage signal kVset and an enable signal / KV_EN to the voltage control unit.

[0140] One embodiment of this application provides a high-voltage generator, which includes a frequency converter control circuit as described in any embodiment of this application.

[0141] As an example, refer to Figure 8 The 380VAC three-phase power input is rectified and filtered to obtain a 540VDC DC voltage, which provides the DC bus voltage to the inverter input. Under the control of the drive signal, the inverter inverts this DC bus voltage and converts it into a high-frequency AC voltage. This high-frequency AC voltage is output to the high-voltage module, where it is first stepped up by a transformer and then rectified by a voltage multiplier to obtain the required DC high voltage. This DC high voltage is then sampled by voltage divider to obtain the KV feedback value of the DC high voltage. The KV feedback value is returned to the frequency regulation controller. At the same time, the inverter frequency is collected in real time through real-time inverter current sampling, and the feedback value of the inverter current is also introduced into the frequency regulation controller. The inverter frequency is changed to stabilize the output DC high voltage through the dual closed-loop control regulation of KV feedback and inverter current.

[0142] Although preferred embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.

[0143] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0144] The above provides a detailed description of the frequency converter control circuit and high voltage generator provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A variable frequency inverter control circuit, characterized in that, include: Input components, inverter components, frequency regulation components, and output components; The inverter component is connected to the input component, the frequency adjustment component, and the output component, respectively; The frequency adjustment component is connected to the output component; The output voltage of the input component is transmitted to the inverter component; the inverter voltage of the inverter component is transmitted to the output component; the current feedback signal of the inverter component is transmitted to the frequency adjustment component; the voltage feedback signal of the output component is transmitted to the frequency adjustment component; and the inverter drive signal of the frequency adjustment component is transmitted to the inverter component.

2. The frequency converter control circuit according to claim 1, characterized in that, include: Voltage control unit, current control unit, triangular wave oscillation unit, and drive unit; The voltage control unit is connected to the current control unit and the output component, respectively; The inverter component is connected to the current control unit, the triangular wave oscillation unit, and the drive unit respectively; the drive unit is connected to the current control unit and the triangular wave oscillation unit respectively. A preset reference voltage and the voltage feedback signal are input to the voltage control unit; the current feedback signal and the voltage error signal of the voltage control unit are input to the current control unit; the current sampling signal of the inverter component is transmitted to the triangular wave oscillation unit; the output signal of the current control unit and the triangular wave signal of the triangular wave oscillation unit are transmitted to the drive unit; the inverter drive signal of the drive unit is transmitted to the inverter component.

3. The frequency converter control circuit according to claim 2, characterized in that, The voltage control unit includes: operational amplifier U1A and operational amplifier U1B; The inverting input terminal of the operational amplifier U1A is connected to one end of resistor R3 and one end of resistor R6; the other end of resistor R3 is connected to one end of resistor R1. The non-inverting input terminal of the operational amplifier U1A is connected to one end of the resistor R5; the other end of the resistor R5 is grounded. The output terminal of the operational amplifier U1A is connected to the other end of resistor R6 and one end of resistor R8; the other end of resistor R8 is connected to one end of resistor R12. The inverting input terminal of the operational amplifier U1B is connected to the positive terminal of diode D7, one end of resistor R14, one end of resistor R9, and the other end of resistor R12; the other end of resistor R14 is connected to one end of capacitor C6; and the other end of resistor R9 is connected to the output component. The non-inverting input terminal of the operational amplifier U1B is connected to one end of the resistor R13; the other end of the resistor R13 is grounded. The output terminal of the operational amplifier U1B is connected to the negative terminal of diode D7, the other end of capacitor C6, and one end of resistor R15; the other end of resistor R15 is connected to the input terminal of the current control unit. The preset reference voltage is input to the other end of the resistor R1; the voltage feedback signal is input to the other end of the resistor R9.

4. The frequency converter control circuit according to claim 2, characterized in that, The current control unit includes: an operational amplifier U2A and a current transformer T1; The input terminal of the current transformer T1 is connected to the inverter assembly; The first output terminal of the current transformer T1 is connected to the positive terminal of diode D10 and the negative terminal of diode D12. The second output terminal of the current transformer T1 is connected to one end of the capacitor C21; the other end of the capacitor C21 is connected to the positive terminal of diode D11 and the negative terminal of diode D13; the positive terminals of diode D12 and diode D13 are grounded. The non-inverting input terminal of the operational amplifier U2A is connected to one end of the resistor R31; the other end of the resistor R31 is connected to the voltage control unit. The inverting input terminal of the operational amplifier U2A is connected to the positive terminal of diode D9, one end of capacitor C11, one end of resistor R27, one end of resistor R29, and one end of resistor R30; the other end of resistor R29 is connected to one end of capacitor C12; the other end of capacitor C12 is connected to the other end of resistor R30, the negative terminal of diode D10, and the negative terminal of diode D11. The output terminal of the operational amplifier U2A is connected to the negative terminal of diode D9, the other end of capacitor C11, the other end of resistor R27, and the driving unit.

5. The frequency converter control circuit according to claim 4, characterized in that, The output terminal of the operational amplifier U2A is connected to the driving unit through the operational amplifier U2B; The output terminal of the operational amplifier U2A is connected to the positive terminal of the diode D8; The non-inverting input of the operational amplifier U2B is connected to one end of resistor R21 and one end of resistor R24; the other end of resistor R21 is grounded; and the other end of resistor R24 ​​is connected to the negative terminal of diode D8. The inverting input terminal of the operational amplifier U2B is connected to one end of resistor R7 and one end of resistor R19; the other end of resistor R7 is grounded. The output terminal of the operational amplifier U2B is connected to the other end of the resistor R19 and the driving unit.

6. The frequency converter control circuit according to claim 2, characterized in that, The triangular wave oscillation unit includes: a current transformer T2, a comparator U4, a comparator U5, a NAND gate U6, and a MOSFET Q3; The input terminal of the current transformer T2 is connected to the inverter assembly; the first output terminal of the current transformer T2 is connected to one end of the resistor R40 and one end of the inductor L1; the second output terminal of the current transformer T2 is grounded. The non-inverting input terminal of the comparator U4 is connected to the other end of resistor R40 and one end of resistor R38. The inverting input of comparator U4 is connected to one end of resistor R39; the other end of resistor R39 is grounded. The first complementary output of the comparator U4 is connected to the other end of the resistor R38 and pin 2B of the NAND gate U6. The second complementary output of the comparator U4 is connected to pin 1A of the NAND gate U6; The non-inverting input terminal of the comparator U5 is connected to one end of resistor R43 and one end of resistor R44; the other end of resistor R44 is connected to one end of resistor R46 and the other end of inductor L1. The inverting input of comparator U5 is connected to one end of resistor R45; the other end of resistor R45 is connected to the other end of resistor R46 and ground. The first complementary output terminal of the comparator U5 is connected to the other end of the resistor R43 and pin 1B of the NAND gate U6. The second complementary output terminal of the comparator U5 is connected to pin 2A of the NAND gate U6 and the driving unit; The NAND gate U6 is connected to the driving unit via MOS transistor Q3.

7. The frequency converter control circuit according to claim 6, characterized in that, The 1Y pin of the NAND gate U6 is connected to the 3A pin of the NAND gate U6 and the driving unit; the 2Y pin of the NAND gate U6 is connected to the 3B pin of the NAND gate U6 and the driving unit; the 3Y pin of the NAND gate U6 is connected to one end of the resistor R37. The gate of the MOS transistor Q3 is connected to one end of resistor R36 and the other end of resistor R37. The source of the MOSFET Q3 is connected to one end of the capacitor C15, the positive terminal of the Zener diode DZ4, the other end of the resistor R36, and the ground wire. The drain of the MOS transistor Q3 is connected to the other end of the capacitor C15, the cathode of the Zener diode DZ4, and the driving unit.

8. The frequency converter control circuit according to claim 2, characterized in that, The driving unit includes: comparator U3, flip-flop U7, driver U8, MOSFET Q2, MOSFET Q4, MOSFET Q5 and MOSFET Q6; The inverting input of the comparator U3 is connected to one end of the resistor R17; the other end of the resistor R17 is connected to the current control unit. The non-inverting input of the comparator U3 is connected to one end of the resistor R18; the other end of the resistor R18 is connected to one end of the resistor R16 and the triangular wave oscillation unit. The output of the comparator U3 is connected to the other end of the resistor R16 and the CLK pin of the flip-flop U7; The triangular wave oscillation unit is connected to the CLR pin, PRE pin and D pin of the trigger U7 respectively; The first input terminal of the driver U8 is connected to the first Q pin of the flip-flop U7; the second input terminal of the driver U8 is connected to the second Q pin of the flip-flop U7. The first output terminal of the driver U8 is connected to the anode of diode D14, the cathode of diode D15, one end of resistor R33, and one end of resistor R34; the gate of the MOSFET Q2 is connected to the cathode of diode D14 and the other end of resistor R33; the source of the MOSFET Q2 is connected to one end of capacitor C14 and the +12V power supply; the gate of the MOSFET Q4 is connected to the anode of diode D15 and the other end of resistor R34; the source of the MOSFET Q4 is connected to the other end of capacitor C14 and ground. The second output terminal of the driver U8 is connected to the anode of diode D16, the cathode of diode D17, one end of resistor R41, and one end of resistor R42; the gate of the MOSFET Q5 is connected to the cathode of diode D16 and the other end of resistor R41; the source of the MOSFET Q5 is connected to one end of capacitor C23 and the +12V power supply; the gate of the MOSFET Q4 is connected to the anode of diode D17 and the other end of resistor R42; the source of the MOSFET Q4 is connected to the other end of capacitor C23 and ground. The first input terminal of transformer T3 is connected to the drain of MOSFET Q2 and the drain of MOSFET Q4; the second input terminal of transformer T3 is connected to one end of capacitor C22; the other end of capacitor C22 is connected to the drain of MOSFET Q5 and the drain of MOSFET Q6; the output terminal of transformer T3 is connected to the inverter assembly.

9. The frequency converter control circuit according to claim 1, characterized in that, The input component includes a rectifier unit and a filter unit; the filter unit is connected to both the rectifier unit and the inverter component; the power supply current is input to the filter unit; the filtered current of the filter unit is transmitted to the rectifier unit; and the rectified current of the rectifier unit is input to the inverter component.

10. A high-voltage generator, characterized in that, Includes the frequency converter control circuit as described in any one of claims 1-9.

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