Radio frequency ion electric propulsion screen grid power supply power circuit and control circuit

Abstract

The invention belongs to the technical field of radio frequency ion electric propulsion, and discloses a radio frequency ion electric propulsion screen grid power supply power circuit and a control circuit. The power circuit comprises an input filter capacitor Cin, a primary side current sampling circuit, a first-stage frequency doubling synchronous rectification BUCK converter, a second-stage current type push-pull isolation converter, a two-stage series bridge type voltage doubling rectification circuit, an output voltage sampling circuit and an output current sampling circuit. The two-stage series bridge type voltage doubling rectifying circuit, the output current sampling circuit and the output voltage sampling circuit are connected in sequence, and the output voltage sampling circuit is used for being connected with a thruster screen grid load; the first-stage frequency doubling synchronous rectification BUCK converter, the second-stage current type push-pull isolation converter and the two-stage series bridge type voltage doubling rectification circuit are connected through a power transformer T1. The invention is used for solving the technical problem that the screen grid power supply and the power supply bus thereof are impacted by the discharge surge current because effective peak current control cannot be carried out by the overcurrent protection measure of the existing screen grid power supply.

Description

Technical Field

[0001] The invention belongs to the technical field of radio frequency ion electric propulsion, and relates to a radio frequency ion electric propulsion screen grid power supply power circuit and a control circuit. Background Art

[0002] As a high-performance micro-electric propulsion technology, RF ion electric propulsion technology has the advantages of high specific impulse, plume collimation, simple structure, and easy miniaturization. It has broad application prospects in the field of commercial micro-satellites. The RF ion electric propulsion system consists of RF ion thrusters, neutralizers, power processing and control units, RF power processing units, and storage and supply units. Among them, the power processing and control unit consists of a DC power processing unit and a digital interface and control unit. The DC power processing unit supplies power to the screen grid and acceleration grid of the thruster, the contact holding electrode (ignition electrode) and the heater of the hollow cathode neutralizer, and the digital interface and control unit completes the measurement and control functions of various parts of the electric propulsion system. Among them, the screen grid power supply is a high-voltage and high-power power supply in the DC power processing unit, and its output power accounts for more than 80% of the total output power of the DC power processing unit.

[0003] The RF ion electric propulsion screen grid power supply has the characteristics of high voltage and low current output, and its output voltage range is wide, and the output voltage is generally in the kilovolt level; its maximum output current is related to the thrust of the thruster, and the maximum output current of the screen grid power supply supporting the mN-level RF ion electric thruster is generally tens to hundreds of mA. At the moment of thruster ignition, the thruster screen grid equivalent impedance of the RF ion electric propulsion system changes from high resistance (MΩ level) to low resistance (kΩ level). At this time, since the acceleration grid is not powered, the thruster is unstable, the screen grid equivalent impedance is small, the screen grid working current is large, and there is frequent sparking and discharge of the screen grid to the acceleration grid; after the acceleration grid is powered, there is also the situation of sparking and discharging of the screen grid to the acceleration grid during the steady-state operation of the thruster, and the sparking and discharging generates an instantaneous large current, the peak value of which is about dozens of times the steady-state output current of the screen grid power supply, and about hundreds of times the steady-state output current of the acceleration grid power supply.

[0004] The current screen-grid power supply mostly adopts single-loop feedback regulation of output voltage. When facing complex or harsh working conditions, its power output dynamic and steady-state performance is poor, the dynamic response speed is slow, and the power supply voltage and current cannot be adjusted in time, and even the harsh working conditions are further aggravated. In the period from the ignition of the thruster to the power supply of the acceleration grid, the screen-grid power supply with single-loop feedback regulation of output voltage cannot complete the switching of the output mode, resulting in overcurrent protection of the primary input of the converter, and the output voltage of the screen-grid power supply drops or even has no output. In the case of the screen-grid ignition discharge to the acceleration grid, due to the uncertainty of the ignition time, the overcurrent protection measures of the current screen-grid power supply cannot effectively suppress the peak current for the ignition condition of extremely narrow pulses (below μS level), causing the screen-grid power supply and its power supply bus to be impacted by the discharge surge current, and in severe cases, causing damage to the screen-grid power supply and its power supply system. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a radio frequency ion electric propulsion screen grid power supply power circuit and control circuit, which adaptively adjusts the power supply constant voltage and constant current dual output mode according to the equivalent impedance state of the thruster screen grid, collects the primary side current of the power supply for overload protection, improves stability, and solves the technical problem that the overcurrent protection measures of the existing screen grid power supply cannot effectively control the peak current, causing the screen grid power supply and its power supply bus to suffer from discharge surge current shocks.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The present invention provides a radio frequency ion electric propulsion screen grid power supply power circuit, comprising an input filter capacitor Cin, a primary current sampling circuit, a first-stage frequency doubling synchronous rectification BUCK converter, a second-stage current type push-pull isolation converter, a two-stage series bridge voltage doubling rectification circuit, an output voltage sampling circuit, and an output current sampling circuit. The two-stage series bridge voltage doubling rectification circuit, the output current sampling circuit, and the output voltage sampling circuit are connected in sequence, and the output voltage sampling circuit is used to be connected to a thruster screen grid load; the first-stage frequency doubling synchronous rectification BUCK converter, the second-stage current type push-pull isolation converter, and the two-stage series bridge voltage doubling rectification circuit are connected via a power transformer T1.

[0008] Furthermore, the primary current sampling circuit includes a current transformer T2, a magnetic reset resistor R1, a filter capacitor C5, a signal output diode V5, and a current-voltage signal conversion resistor R2; pin 1 of the current transformer T2 is connected to one end of the input filter capacitor Cin and to the power supply positive line Vin+, pin 2 of the current transformer T2 is connected to the first-stage frequency doubling synchronous rectification BUCK converter, pin 3 of the current transformer T2 is connected to the anode of the signal output diode V5, and pin 4 of the current transformer T2 is connected to the power supply ground CGnd of the PWM pulse width modulation circuit. The magnetic reset resistor R1 is connected in parallel with the filter capacitor C5, one end is connected to pin 3 of the current transformer T2, and the other end is connected to pin 4 of the current transformer T2. The anode of the signal output diode V5 is connected to pin 3 of the current transformer T2, and the cathode is connected to the primary current sampling signal IS. One end of the current-voltage signal conversion resistor R2 is connected to the primary current sampling signal IS, and the other end is connected to the power supply ground CGnd of the PWM pulse width modulation circuit.

[0009] Further, the first-stage frequency-doubling synchronous rectification BUCK converter includes an N MOS tube Q1, an N MOS tube Q2, an NMOS tube Q3 and a filter inductor L1; the drain of the N MOS tube Q1 is connected to the drain of the N MOS tube Q2, and is connected to pin 2 of the current transformer T2, the source of the N MOS tube Q1 is connected to the source of the N MOS tube Q2 and is connected to the drain of the N MOS tube Q3, the drain of the N MOS tube Q3 is also connected to one end of the filter inductor L1, the source of the N MOS tube Q3 is connected to the other end of the input filter capacitor Cin, and is connected to the power supply return line VinGnd, the other end of the filter inductor L1 is connected to the power transformer T1, and the gate of the N MOS tube Q1 is connected to the first drive signal V Q1gs The gate of N MOS tube Q2 is connected to the second driving signal V Q2gs The gate of N MOS tube Q3 is connected to the third driving signal V Q3gs .

[0010] Further, the pins 1, 3, 5 and 7 of the power transformer T1 are the same-named terminals, and the pins 2, 4, 6 and 8 are the same-named terminals. The pins 2 and 3 of the power transformer T1 are connected to the first-stage frequency-doubling synchronous rectification BUCK converter, and the pins 1 and 4 are connected to the second-stage current-type push-pull isolation converter; the second-stage current-type push-pull isolation converter includes an N MOS tube Q4 and an N MOS tube Q5, the drain of the N MOS tube Q4 is connected to the pin 1 of the power transformer T1, the source of the N MOS tube Q4 is connected to the power supply return line VinGnd, and the gate of the N MOS tube Q4 is connected to the fourth drive signal V Q4gsThe drain of the N MOS tube Q5 is connected to the 4th pin of the power transformer T1, the source of the N MOS tube Q5 is connected to the power supply return line VinGnd, and the gate of the N MOS tube Q5 is connected to the fifth drive signal V Q5gs .

[0011] Furthermore, the two-stage series bridge voltage doubler rectifier circuit includes a rectifier diode V1, a rectifier diode V2, a rectifier diode V3, a rectifier diode V4, a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4; the anode of the rectifier diode V1 is connected to pin 5 of the power transformer T1, the cathode is connected to one end of the capacitor C1 and the positive power supply terminal Vout+ of the power supply output, and the other end of the capacitor C1 is connected to pin 6 of the power transformer T1; the cathode of the rectifier diode V2 is connected to pin 5 of the power transformer T1, the anode is connected to one end of the capacitor C2 and the cathode of the rectifier diode V3, and the other end of the capacitor C2 is connected to pin 6 of the power transformer T1; the anode of the rectifier diode V3 is connected to pin 7 of the power transformer T1, the cathode is connected to one end of the capacitor C3, and the other end of the capacitor C3 is connected to pin 8 of the power transformer T1; the cathode of the rectifier diode V4 is connected to pin 7 of the power transformer T1, the anode is connected to one end of the capacitor C4 and one end of the output current sampling circuit, and the other end of the capacitor C4 is connected to pin 8 of the power transformer T1.

[0012] Furthermore, one end of the output voltage sampling circuit is connected to the power supply positive terminal Vout+, and the other end is connected to the power supply output ground line VoutGnd; the output voltage sampling circuit converts the power supply output voltage signal into an output voltage sampling signal Vcy.

[0013] Furthermore, one end of the output current sampling circuit is connected to the anode of the rectifier diode V4, and the other end is connected to the power supply output ground line VoutGnd.

[0014] A radio frequency ion electric propulsion screen grid power supply control circuit is based on the above radio frequency ion electric propulsion screen grid power supply power circuit, and its special features are that it includes an output voltage PID negative feedback control circuit, an output current PID negative feedback control circuit, a feedback signal comparison circuit, a PWM pulse width modulation circuit, and an isolation drive circuit; the output voltage PID negative feedback control circuit receives an output voltage sampling signal Vcy from an output voltage sampling circuit, compares it with an output voltage reference signal Vset at the same phase end of an operational amplifier, performs a negative feedback PID loop operation, and forms an output voltage feedback signal; the output current PID negative feedback control circuit receives an output current sampling signal Icy from an output current sampling circuit, compares it with an output current reference signal Iset at the same phase end of an operational amplifier, performs a negative feedback PID loop operation, and forms an output current feedback signal.

[0015] Furthermore, the feedback signal comparison circuit includes a diode V6 and a diode V7, the cathode of the diode V6 is connected to the output voltage PID negative feedback control circuit, the anode is connected to the anode of the diode V7 and is connected to the PWM pulse width modulation circuit, and the cathode of the diode V7 is connected to the output current PID negative feedback control circuit.

[0016] Furthermore, the isolation driving circuit outputs the pulse width modulation output signal output by the PWM pulse width modulation circuit through the driving transformer to output the first driving signal V Q1gs , the second driving signal V Q2gs , the third driving signal V Q3gs , the fourth driving signal V Q4gs , the fifth driving signal V Q5gs .

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] The present invention discloses a radio frequency ion electric propulsion screen grid power supply circuit. The primary side adopts a two-stage power topology, realizes output feedback closed-loop control through a first-stage frequency doubling synchronous rectification BUCK converter, uses a filter inductor L1 to effectively suppress peak current, and realizes power isolation transmission through a second-stage current type push-pull isolation converter working at a fixed frequency and full duty cycle, thereby improving the power supply working efficiency. The secondary side adopts a two-stage series bridge voltage doubling rectifier circuit, which has the advantages of small component stress and small output voltage ripple. The screen grid power supply samples the primary current signal, output voltage signal and output current signal, and transmits them to related functional circuits, thereby realizing the functions of primary side overcurrent protection, output voltage PID negative feedback control, output current PID negative feedback control, etc., and can perform adaptive adjustment of the power supply constant voltage and constant current dual output mode according to the equivalent impedance state of the thruster screen grid, thereby meeting the power supply demand of the screen grid during the thruster ignition and working process, and ensuring the stability and reliability of the radio frequency ion propulsion system.

[0019] A radio frequency ion electric propulsion screen grid power supply power circuit of the present invention has triple overcurrent protection. Through the triple overcurrent protection, the working reliability and power supply stability of the screen grid power supply under all working conditions are improved, and the robustness of the radio frequency ion electric propulsion system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A circuit diagram of a radio frequency ion electric propulsion screen grid power supply circuit of the present invention;

[0021] Figure 2 A circuit diagram of a radio frequency ion electric propulsion screen grid power supply control circuit of the present invention;

[0022] Figure 3Schematic diagram of waveforms of a first driving signal, a second driving signal, a third driving signal, a fourth driving signal and a fifth driving signal in an embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 only 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 ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0024] Example 1

[0025] The present invention provides a radio frequency ion electric propulsion screen grid power supply circuit, such as Figure 1 As shown, it includes an input filter capacitor Cin, a primary current sampling circuit, a first-stage frequency doubling synchronous rectification BUCK converter, a second-stage current-type push-pull isolation converter, a two-stage series bridge voltage doubling rectifier circuit, an output voltage sampling circuit, an output current sampling circuit, and a power transformer T1.

[0026] The primary current sampling circuit includes a current transformer T2, a magnetic reset resistor R1, a filter capacitor C5, a signal output diode V5, and a current-voltage signal conversion resistor R2; the first-stage frequency doubling synchronous rectification BUCK converter includes an N MOS tube Q1, an N MOS tube Q2, an N MOS tube Q3 and a filter inductor L1; the second-stage current-type push-pull isolation converter includes an N MOS tube Q4 and an N MOS tube Q5; the two-stage series bridge voltage doubling rectification circuit includes a rectifier diode V1, a rectifier diode V2, a rectifier diode V3, a rectifier diode V4, a capacitor C1, a capacitor C2, a capacitor C3, and a capacitor C4; the output voltage sampling circuit outputs a voltage sampling signal Vcy, and the output current sampling circuit outputs a current sampling signal Icy.

[0027] Specifically, one end of the input filter capacitor Cin is connected to the positive power supply line Vin+, and the other end is connected to the power supply return line VinGnd. The input filter capacitor Cin can store and release energy, reduce the peak value of the AC ripple of the power supply bus, make it efficient and smooth DC output, and filter out high-frequency noise in the power supply to ensure the stability and reliability of the circuit.

[0028] The current transformer T2 in the primary current sampling circuit includes four pins. Pin 1 of the current transformer T2 is connected to the positive power supply line Vin+ and to one end of the filter capacitor Cin. Pin 2 of the current transformer T2 is connected to the drain of the N MOS tube Q1. Pin 3 of the current transformer T3 is connected to the anode of the output diode V5. Pin 4 of the current transformer T2 is connected to the power supply ground CGnd of the PWM pulse width modulation circuit.

[0029] It should be noted that, in the present embodiment, D of the NMOS transistor Q1 , the NMOS transistor Q2 , the NMOS transistor Q3 , the NMOS transistor Q4 , and the NMOS transistor Q5 is a drain, S is a source, and G is a gate.

[0030] Pin 1 and pin 3 of the current transformer T2 are the same-name terminals, and pin 2 and pin 4 are the same-name terminals.

[0031] One end of the magnetic reset resistor R1 is connected to one end of the filter capacitor C5 and to pin 3 of the current transformer T2, and the other end of the magnetic reset resistor R1 is connected to the other end of the filter capacitor C5 and to pin 4 of the current transformer T2. In other words, the magnetic reset resistor R1 is connected in parallel with the filter capacitor C5, one end is connected to pin 3 of the current transformer T2, and the other end is connected to pin 4 of the current transformer T2.

[0032] The anode of the signal output diode V5 is connected to pin 3 of the current transformer T2, and the cathode is connected to the primary current sampling signal IS. It is also connected to one end of the current-voltage signal conversion resistor R2, and the other end of the current-voltage signal conversion resistor R2 is connected to the power supply ground CGnd of the PWM pulse width modulation circuit.

[0033] The primary current sampling circuit collects the primary current through the current transformer T2, and sends the primary current sampling signal to the PWM pulse width modulation circuit, thereby realizing primary overcurrent protection. The magnetic reset resistor R1 performs magnetic reset of the current transformer when the primary current returns to zero to avoid magnetic saturation of the current transformer. The current-voltage signal conversion resistor R2 converts the current signal output by the signal output diode V5 into a voltage signal.

[0034] In the first-stage frequency-doubling synchronous rectification BUCK converter, the drain of the N MOS tube Q1 is connected to the drain of the N MOS tube Q2, and is connected to the 2nd pin of the current transformer T2. The source of the N MOS tube Q1 is connected to the source of the N MOS tube Q2 and is connected to the drain of the N MOS tube Q3. The drain of the N MOS tube Q3 is also connected to one end of the filter inductor L1. The source of the N MOS tube Q3 is connected to the other end of the input filter capacitor Cin and is connected to the power supply return line VinGnd. The other end of the filter inductor L1 is connected to the power transformer T1. The gate of the N MOS tube Q1 is connected to the first drive signal V Q1gsThe gate of N MOS tube Q2 is connected to the second driving signal V Q2gs The gate of N MOS tube Q3 is connected to the third driving signal V Q3gs .

[0035] The first-stage frequency-doubled synchronous rectification BUCK converter adjusts the wide-range input voltage to the stable input voltage required by the second-stage current-type push-pull isolation converter by controlling the PWM duty cycle of the Buck converter through power supply output feedback and error amplification.

[0036] Among them, the operating frequency of the N MOS tube Q1 and the N MOS tube Q2 is the same, the phase difference between the two is 180°, and they are alternately turned on, so that the Buck converter can achieve frequency doubling; the operating frequency of the N MOS tube Q3 and the filter inductor L1 is twice the operating frequency of the N MOS tube Q1 and the N MOS tube Q2. On the one hand, the operating frequency of the converter is improved and the volume and weight of the input filter capacitor Cin and the filter inductor L1 are reduced. On the other hand, the operating frequency of the N MOS tube Q1 and the N MOS tube Q2 is consistent with the operating frequency of the second-stage current-type push-pull isolation converter switch tube, which is convenient for the overall drive control of the power supply.

[0037] N MOS tube Q3 is a freewheeling tube, which adopts synchronous rectification control to improve the working efficiency of the converter. The filter inductor L1 provides input current for the second-stage current-type push-pull isolation converter. Due to the self-inductance and back electromotive force characteristics of the inductor, the current flowing through the filter inductor L1 cannot change suddenly. Therefore, the circuit naturally has the characteristics of transient current suppression, which can effectively suppress the peak current of abnormal working conditions such as the screen grid ignition discharge of the acceleration grid, and prevent the screen grid power supply and its power supply bus from being impacted by discharge surge current.

[0038] The drain of the NMOS tube Q4 in the second-stage current-type push-pull isolation converter is connected to the 1st pin of the power transformer T1, the source of the NMOS tube Q4 is connected to the power supply return line VinGnd, and the gate of the NMOS tube Q4 is connected to the fourth drive signal V Q4gs .

[0039] The drain of the N MOS tube Q5 is connected to the 4th pin of the power transformer T1, the source of the N MOS tube Q5 is connected to the power supply return line VinGnd, and the gate of the N MOS tube Q5 is connected to the fifth drive signal V Q5gs .

[0040] Pins 1, 3, 5 and 7 of the power transformer T1 are the same-named terminals, and pins 2, 4, 6 and 8 are the same-named terminals. Pins 2 and 3 of the power transformer T1 are connected to the first-stage frequency-doubling synchronous rectification BUCK converter, pins 1 and 4 are connected to the second-stage current-type push-pull isolation converter, and pins 5, 6, 7 and 8 are connected to the two-stage series bridge voltage-doubling rectifier circuit.

[0041] The second-stage current-type push-pull isolation converter uses power transformer T1 for power transmission and magnetic isolation. The converter adopts fixed-frequency control. The operating frequency of N MOS tube Q4 and N MOS tube Q5 is the same, and the phase difference between the two is 180°. They are alternately turned on to convert the input DC signal into an AC pulse signal, which is transmitted to the secondary side through the transformer. The output signal of the secondary side is rectified by a two-stage series bridge voltage doubler rectifier circuit and then outputs a DC voltage.

[0042] The duty cycle of the N MOS tube Q4 and the N MOS tube Q5 is greater than 50%, and there is no dead time, so that the filter inductor L1 in the first-stage frequency-doubled synchronous rectification BUCK converter is freewheeling, so that the output current of the inductor is continuous, and the inductor components in the secondary rectification and filtering circuit of the power supply can be reduced. In addition, there is no need to increase the output filter capacitor of the first-stage frequency-doubled synchronous rectification BUCK converter, which reduces the overall volume and weight of the power supply. Since the current of the filter inductor L1 cannot change suddenly, there is no problem of current overshoot, over-loss and excessive voltage stress of the rectifier tube at the moment of the switch tube being turned on, and there is no problem of the bridge arm switch tube being turned on together.

[0043] In this converter, N MOS tube Q4 and N MOS tube Q5 are turned on alternately. Compared with other converters, it is equivalent to having two switch tubes transmitting the same power, and the conduction loss of the switch tube is small. The power transmission process of this converter exists in the entire switching cycle, the pulsation of its secondary voltage is small, and the transient characteristics of the current are good. The magnetic core of the power transformer T1 of this converter works in the first and third quadrants, and the magnetic core utilization rate is high.

[0044] In the two-stage series bridge voltage doubler rectifier circuit, the anode of the rectifier diode V1 is connected to the 5th pin of the power transformer T1, the cathode is connected to one end of the capacitor C1 and the positive end Vout+ of the power output, and the other end of the capacitor C1 is connected to the 6th pin of the power transformer T1; the cathode of the rectifier diode V2 is connected to the 5th pin of the power transformer T1, the anode is connected to one end of the capacitor C2 and the cathode of the rectifier diode V3, and the other end of the capacitor C2 is connected to the 6th pin of the power transformer T1; the anode of the rectifier diode V3 is connected to the 7th pin of the power transformer T1, the cathode is connected to one end of the capacitor C3, and the other end of the capacitor C3 is connected to the 8th pin of the power transformer T1; the cathode of the rectifier diode V4 is connected to the 7th pin of the power transformer T1, the anode is connected to one end of the capacitor C4 and one end of the output current sampling circuit, and the other end of the capacitor C4 is connected to the 8th pin of the power transformer T1.

[0045] The two-stage series bridge voltage doubler rectifier circuit is composed of two identical bridge voltage doubler rectifier circuits connected in series. The Ns1 winding and the Ns2 winding of the power transformer T1 have the same number of turns and the same output voltage. When the Ns1 winding and the Ns2 winding work in the positive half cycle, the rectifier diodes V1 and V3 are turned on, the rectifier diodes V2 and V4 are turned off, the voltage at the capacitor C1 terminal is the voltage at the winding Ns1 terminal, and the voltage at the capacitor C3 terminal is the voltage at the winding Ns2 terminal; when the Ns1 winding and the Ns2 winding work in the negative half cycle, the rectifier diodes V2 and V4 are turned on, the rectifier diodes V1 and V3 are turned off, the voltage at the capacitor C2 terminal is the voltage at the winding Ns1 terminal, and the voltage at the capacitor C4 terminal is the voltage at the winding Ns2 terminal, thereby achieving voltage doubling. The sum of the terminal voltages of capacitors C1, C2, C3, and C4 is the output voltage of the power supply. The circuit realizes voltage doubling rectification output through a series bridge structure, reduces the voltage stress of the power transformer winding and various components in the circuit, and reduces the output voltage ripple, which is suitable for high-voltage and low-current output power supplies.

[0046] One end of the output voltage sampling circuit is connected to the positive terminal Vout+ of the power supply output, and the other end is connected to the power supply output ground line VoutGnd. The output voltage sampling circuit converts the power supply output voltage signal into an output voltage sampling signal Vcy, and at the same time realizes high-resistance isolation between the power supply output ground line VoutGnd and the internal control ground CGnd of the power supply, so as to avoid the ground disturbance on the load side of the power supply affecting the steady-state operation of the power supply during the operation of the power supply.

[0047] One end of the output current sampling circuit is connected to the common end of the rectifier diode V4 and the capacitor C4, and the other end is connected to the power supply output ground line VoutGnd. The output current sampling circuit converts the power supply output current signal into an output current sampling signal Icy, and at the same time realizes high-impedance isolation between the power supply output ground line VoutGnd and the power supply internal control ground CGnd, so as to avoid the ground disturbance on the load side of the power supply affecting the steady-state operation of the power supply during the power supply operation.

[0048] In summary, the power circuit of the RF ion electric propulsion screen grid power supply adopts a two-stage power topology on the primary side, realizes output feedback closed-loop control through the first-stage frequency doubling synchronous rectification BUCK converter, uses the filter inductor L1 for effective peak current suppression, and realizes power isolation transmission through the second-stage current-type push-pull isolation converter working at a fixed frequency and full duty cycle, and improves the power supply working efficiency. The secondary side of the screen grid power supply power circuit adopts a two-stage series bridge voltage doubling rectifier circuit, which has the advantages of low component stress and small output voltage ripple. The screen grid power supply samples the primary current signal, output voltage signal and output current signal, and transmits the sampled signal to the relevant functional circuit, thereby realizing the primary side overcurrent protection, output voltage PID negative feedback control, output current PID negative feedback control and other functions.

[0049] Example 2

[0050] A radio frequency ion electric propulsion screen grid power supply control circuit, such as Figure 2 As shown, it includes an output voltage PID negative feedback control circuit, an output current PID negative feedback control circuit, a feedback signal comparison circuit, a PWM pulse width modulation circuit, and an isolation drive circuit; the output voltage PID negative feedback control circuit receives the output voltage sampling signal Vcy of the output voltage sampling circuit, compares it with the output voltage reference signal Vset of the op amp in-phase terminal, performs a negative feedback PID loop operation, and forms an output voltage feedback signal; the output current PID negative feedback control circuit receives the output current sampling signal Icy of the output current sampling circuit, compares it with the output current reference signal Iset of the op amp in-phase terminal, performs a negative feedback PID loop operation, and forms an output current feedback signal.

[0051] Specifically, the output voltage PID negative feedback control circuit includes an operational amplifier N1, a resistor R3, a resistor R4, a resistor R5, a capacitor C6, a capacitor C7, and a capacitor C8. The resistor R4 is connected in series with the capacitor C6 and then connected in parallel with the resistor R3, and one end of the resistor-capacitor network formed is connected to the output voltage sampling signal Vcy, and the other end is connected to the inverting end of the operational amplifier N1. The resistor R5 is connected in series with the capacitor C8 and then connected in parallel with the capacitor C7, and one end of the resistor-capacitor network formed is connected to the inverting end of the operational amplifier N1, and the other end is connected to the output end of the operational amplifier N1. The output end of the operational amplifier N1 is also connected to the cathode of the diode V6 in the feedback signal comparison circuit. The in-phase end of the operational amplifier N1 is connected to the output voltage reference signal Vset.

[0052] The output voltage PID negative feedback control circuit receives the output voltage sampling signal Vcy from the output voltage sampling circuit, compares it with the output voltage reference signal Vset at the in-phase terminal of the operational amplifier, performs negative feedback PID loop operation, and finally forms an output voltage feedback signal.

[0053] The output current PID negative feedback control circuit includes an operational amplifier N2, a resistor R6, a resistor R7, a resistor R8, a capacitor C9, a capacitor C10, and a capacitor C11. The resistor R7 is connected in series with the capacitor C9 and then connected in parallel with the resistor R6. One end of the resistor-capacitor network formed is connected to the output current sampling signal Icy, and the other end is connected to the inverting end of the operational amplifier N2. The resistor R8 is connected in series with the capacitor C11 and then connected in parallel with the capacitor C12. One end of the resistor-capacitor network formed is connected to the inverting end of the operational amplifier N2, and the other end is connected to the output end of the operational amplifier N2. The output end of the operational amplifier N2 is also connected to the cathode of the diode V7 in the feedback signal comparison circuit. The in-phase end of the operational amplifier N2 is connected to the output current reference signal Iset.

[0054] The output current PID negative feedback control circuit receives the output current sampling signal Icy from the output current sampling circuit, compares it with the output current reference signal Iset at the in-phase terminal of the operational amplifier, performs negative feedback PID loop operation, and finally forms an output current feedback signal.

[0055] The feedback signal comparison circuit includes a diode V6 and a diode V7. The cathode of the diode V6 is connected to the output voltage PID negative feedback control circuit, and the anode is connected to the anode of the diode V7 and connected to the PWM pulse width modulation circuit. The cathode of the diode V7 is connected to the output current PID negative feedback control circuit.

[0056] The feedback signal comparison circuit receives the output voltage signal from the output voltage PID negative feedback control circuit and the output voltage signal from the output current PID negative feedback control circuit, compares the two, takes the lower voltage value for output, and sends the final feedback loop control signal to the PWM pulse width modulation circuit.

[0057] The PWM pulse width modulation circuit receives the primary current sampling signal IS and the feedback loop control signal, and realizes functions such as power supply slow start-up, primary side overcurrent protection, current slope compensation, PWM pulse width adjustment, etc. through the PWM pulse width controller and its peripheral circuits, and sends the pulse width modulation output signal to the isolation drive circuit.

[0058] The isolation drive circuit receives the pulse width modulation output signal from the PWM pulse width modulation circuit, realizes magnetic isolation through the driving transformer, and outputs the first drive signal V Q1gs The second driving signal V Q2gs The third driving signal V Q3gs The fourth driving signal V Q4gs The fifth driving signal V Q5gs The waveform and timing relationship of each driving signal is as follows: Figure 3 shown.

[0059] In summary, a radio frequency ion electric propulsion screen grid power supply control circuit, when the power supply output is high voltage and low current, the voltage of the output current sampling signal Icy is low, the output voltage of the output current PID negative feedback control circuit is higher than the output voltage of the output voltage PID negative feedback control circuit, and the power supply works in the voltage loop to achieve constant voltage and stable output. When the output current of the power supply increases to the set output current reference signal Iset, the output voltage of the output current PID negative feedback control circuit is lower than the output voltage of the output voltage PID negative feedback control circuit, and the power supply works in the current loop to achieve constant current and stable output. In this way, the screen grid power supply can be adaptively adjusted in a constant voltage and constant current dual output mode according to the load impedance of the thruster screen grid, so as to meet the power supply requirements of the screen grid during the ignition and operation of the thruster, and ensure the stability and reliability of the operation of the radio frequency ion propulsion system.

[0060] Example 3

[0061] A radio frequency ion electric propulsion screen grid power supply control circuit can add a reverse follower circuit at the rear stage of the output voltage sampling circuit. The output signal of the circuit is a telemetry signal of the screen grid power supply output voltage, thereby realizing the screen grid power supply output voltage telemetry function.

[0062] A radio frequency ion electric propulsion screen grid power supply control circuit can add a reverse follower circuit at the rear stage of the output current sampling circuit. The output signal of the circuit is a telemetry signal of the screen grid power supply output current, thereby realizing the screen grid power supply output current telemetry function.

[0063] A radio frequency ion electric propulsion screen grid power supply control circuit can divide the Vref level output by a PWM pulse width controller in a PWM pulse width modulation circuit by resistors, thereby forming an output voltage reference signal Vset.

[0064] A radio frequency ion electric propulsion screen grid power supply control circuit can divide the Vref level output by a PWM pulse width controller in a PWM pulse width modulation circuit by resistors, thereby forming an output current reference signal Iset.

[0065] A radio frequency ion electric propulsion screen grid power supply control circuit can replace the output voltage reference signal Vset in the output voltage PID negative feedback control circuit by an external injection level, thereby realizing the screen grid power supply output voltage remote control function.

[0066] A radio frequency ion electric propulsion screen grid power supply control circuit can replace the output current reference signal Iset in the output current PID negative feedback control circuit by an external injection level, thereby realizing the screen grid power supply output current remote control function.

[0067] Example 4

[0068] like Figure 3As shown in FIG. 1 , the waveform and timing relationship of each driving signal are described, and the vertical axis is the first driving signal V Q1gs , the second driving signal V Q2gs , the third driving signal V Q3gs , the fourth driving signal V Q4gs , the fifth driving signal V Q5gs , the first driving signal V Q1gs is the driving signal of the N MOS tube Q1; the second driving signal V Q2gs is the driving signal of the N MOS tube Q2; the third driving signal V Q3gs is the driving signal of the N MOS tube Q3; the fourth driving signal V Q4gs is the driving signal of the N MOS tube Q4; the fifth driving signal V Q5gs is the driving signal of the N MOS tube Q5, and the horizontal axis is the time axis.

[0069] Phase 1 [before T0]: In the first-stage frequency-doubling synchronous rectification BUCK converter, N MOS tube Q3 is turned on, and N MOS tube Q1 and N MOS tube Q2 are turned off; in the second-stage current-type push-pull isolation converter, N MOS tube Q5 is turned on, and N MOS tube Q4 is turned off; in the two-stage series bridge voltage-doubling rectifier circuit, the Ns1 winding and Ns2 winding of the power transformer T1 work in the positive half cycle, the rectifier diodes V1 and V3 are turned on, and the rectifier diodes V2 and V4 are turned off. At this time, the first-stage frequency-doubling synchronous rectification BUCK converter transmits energy to the secondary side of the power supply through the N MOS tube Q5 branch in the second-stage current-type push-pull isolation converter, and the current flowing through the filter inductor L1 is freewheeled through the N MOS tube Q3, and the inductor current decreases linearly.

[0070] Phase 2 [T0-T1]: In the first-stage frequency-doubling synchronous rectifier BUCK converter, NMOS tube Q3 is turned on, and NMOS tube Q1 and NMOS tube Q2 are turned off; in the second-stage current-type push-pull isolation converter, NMOS tube Q4 and NMOS tube Q5 are both turned on, and the push-pull converter enters the state where the switch tubes are jointly turned on, and the two push-pull tube branches evenly divide the current of the filter inductor L1. At this time, the current flowing through the filter inductor L1 is continued through the NMOS tube Q3, the voltage at the upper end of the filter inductor L1 is approximately 0, and the inductor current remains basically unchanged. In the two-stage series bridge voltage doubler rectifier circuit, the voltage at the Ns1 winding and Ns2 winding terminals of the power transformer T1 is approximately 0, the rectifier diode V1, the rectifier diode V2, the rectifier diode V3 and the rectifier diode V4 are all turned off, and the power output current is provided by capacitors C1, C2, C3 and C4, and there is no energy transfer between the primary and secondary sides of the power transformer T1.

[0071] Phase 3 [T1-T2]: NMOS tubes Q1, Q2 and Q3 in the first-stage frequency-doubling synchronous rectifier BUCK converter are all turned off; NMOS tubes Q4 and Q5 in the second-stage current-type push-pull isolation converter remain turned on together, and the two push-pull tube branches evenly divide the current of the filter inductor L1. At this time, the current flowing through the filter inductor L1 is freewheeling through the body diode of the NMOS tube Q3, the voltage at the upper end of the filter inductor L1 is about 0, and the inductor current remains basically unchanged. In the two-stage series bridge voltage doubler rectifier circuit, the voltage at the Ns1 winding and Ns2 winding terminals of the power transformer T1 is about 0, the rectifier diodes V1, V2, V3 and V4 are all turned off, and the power output current is provided by capacitors C1, C2, C3 and C4, and there is no energy transfer between the primary and secondary sides of the power transformer T1.

[0072] Phase 4 [T2-T3]: In the first-stage frequency-doubling synchronous rectifier BUCK converter, NMOS tube Q1 is turned on, and NMOS tube Q2 and NMOS tube Q3 are turned off; in the second-stage current-type push-pull isolation converter, NMOS tube Q4 and NMOS tube Q5 remain turned on together, and the two push-pull tube branches evenly divide the current of the filter inductor L1. The voltages at the Np1 winding and Np2 winding terminals of the power transformer T1 are approximately 0. At this time, the voltage at the upper end of the filter inductor L1 is approximately the power supply input voltage Vin, and the inductor current rises rapidly and linearly. In the two-stage series bridge voltage-doubling rectifier circuit, the voltages at the Ns1 winding and Ns2 winding terminals of the power transformer T1 are approximately 0, and the rectifier diodes V1, V2, V3 and V4 are all turned off. The power output current is provided by capacitors C1, C2, C3 and C4, and there is no energy transfer between the primary and secondary sides of the power transformer T1.

[0073] Phase 5 [T3-T4]: In the first-stage frequency-doubled synchronous rectifier BUCK converter, NMOS tube Q1 is turned on, and NMOS tube Q2 and NMOS tube Q3 are turned off; in the second-stage current-type push-pull isolation converter, NMOS tube Q4 is turned on, and NMOS tube Q5 is turned off; in the two-stage series bridge voltage doubler rectifier circuit, the Ns1 winding and Ns2 winding of the power transformer T1 work in the negative half cycle, the rectifier diodes V2 and V4 are turned on, and the rectifier diodes V1 and V3 are turned off. At this time, the first-stage frequency-doubled synchronous rectifier BUCK converter transmits energy to the secondary side of the power supply through the NMOS tube Q4 branch in the second-stage current-type push-pull isolation converter, and the current flowing through the filter inductor L1 rises linearly.

[0074] Stage 6 [T4-T5]: NMOS tubes Q1, Q2 and Q3 in the first-stage frequency-doubled synchronous rectifier BUCK converter are all turned off; NMOS tube Q4 in the second-stage current-type push-pull isolation converter is turned on, and NMOS tube Q5 is turned off; Ns1 winding and Ns2 winding of power transformer T1 in the two-stage series bridge voltage doubler rectifier circuit work in the negative half cycle, rectifier diodes V2 and V4 are turned on, and rectifier diodes V1 and V3 are turned off. At this time, the current flowing through the filter inductor L1 is freewheeling through the body diode of the NMOS tube Q3, and the inductor current decreases linearly.

[0075] Stage 7 [T5-T6]: In the first-stage frequency-doubled synchronous rectifier BUCK converter, NMOS tube Q3 is turned on, and NMOS tube Q1 and NMOS tube Q2 are turned off; in the second-stage current-type push-pull isolation converter, NMOS tube Q4 is turned on, and NMOS tube Q5 is turned off; in the two-stage series bridge voltage doubler rectifier circuit, the Ns1 winding and Ns2 winding of the power transformer T1 work in the negative half cycle, the rectifier diodes V2 and V4 are turned on, and the rectifier diodes V1 and V3 are turned off. At this time, the current flowing through the filter inductor L1 is continued through the NMOS tube Q3, and the inductor current decreases linearly.

[0076] Stage 8 [T6-T7]: In the first-stage frequency-doubling synchronous rectifier BUCK converter, NMOS tube Q3 is turned on, and NMOS tube Q1 and NMOS tube Q2 are turned off; in the second-stage current-type push-pull isolation converter, NMOS tube Q4 and NMOS tube Q5 are both turned on, and the push-pull converter enters the state where the switch tubes are jointly turned on, and the two push-pull tube branches evenly divide the current of the filter inductor L1. At this time, the current flowing through the filter inductor L1 is continued through the NMOS tube Q3, the voltage at the upper end of the filter inductor L1 is about 0, and the inductor current remains basically unchanged. In the two-stage series bridge voltage doubler rectifier circuit, the voltage at the Ns1 winding and Ns2 winding terminals of the power transformer T1 is about 0, the rectifier diode V1, the rectifier diode V2, the rectifier diode V3 and the rectifier diode V4 are all turned off, and the power output current is provided by capacitors C1, C2, C3 and C4, and there is no energy transfer between the primary and secondary sides of the power transformer T1.

[0077] Stage nine [T7-T8]: NMOS tubes Q1, Q2 and Q3 in the first-stage frequency-doubling synchronous rectifier BUCK converter are all turned off; NMOS tubes Q4 and Q5 in the second-stage current-type push-pull isolation converter remain turned on together, and the two push-pull tube branches evenly divide the current of the filter inductor L1. At this time, the current flowing through the filter inductor L1 is freewheeling through the body diode of the NMOS tube Q3, the voltage at the upper end of the filter inductor L1 is about 0, and the inductor current remains basically unchanged. In the two-stage series bridge voltage doubler rectifier circuit, the voltage at the Ns1 winding and Ns2 winding of the power transformer T1 is about 0, the rectifier diodes V1, V2, V3 and V4 are all turned off, and the power output current is provided by capacitors C1, C2, C3 and C4, and there is no energy transfer between the primary and secondary sides of the power transformer T1.

[0078] Stage 10 [T8-T9]: In the first-stage frequency-doubling synchronous rectifier BUCK converter, NMOS tube Q2 is turned on, while NMOS tube Q1 and NMOS tube Q3 are turned off; in the second-stage current-type push-pull isolation converter, NMOS tube Q4 and NMOS tube Q5 remain turned on together, and the two push-pull tube branches evenly divide the current of the filter inductor L1. The voltages at the Np1 winding and Np2 winding terminals of the power transformer T1 are approximately 0. At this time, the voltage at the upper end of the filter inductor L1 is approximately the power supply input voltage Vin, and the inductor current rises rapidly and linearly. In the two-stage series bridge voltage-doubling rectifier circuit, the voltages at the Ns1 winding and Ns2 winding terminals of the power transformer T1 are approximately 0, and the rectifier diodes V1, V2, V3 and V4 are all turned off. The power output current is provided by capacitors C1, C2, C3 and C4, and there is no energy transfer between the primary and secondary sides of the power transformer T1.

[0079] Stage 11 [T9-T10]: In the first-stage frequency-doubling synchronous rectification BUCK converter, N MOS tube Q2 is turned on, and N MOS tube Q1 and N MOS tube Q3 are turned off; in the second-stage current-type push-pull isolation converter, N MOS tube Q5 is turned on, and N MOS tube Q4 is turned off; in the two-stage series bridge voltage-doubling rectifier circuit, the Ns1 winding and Ns2 winding of the power transformer T1 work in the positive half cycle, the rectifier diodes V1 and V3 are turned on, and the rectifier diodes V2 and V4 are turned off. At this time, the first-stage frequency-doubling synchronous rectification BUCK converter transmits energy to the secondary side of the power supply through the N MOS tube Q5 branch in the second-stage current-type push-pull isolation converter, and the current flowing through the filter inductor L1 rises linearly.

[0080] Stage 12 [T10-T11]: NMOS tubes Q1, Q2 and Q3 in the first-stage frequency-doubled synchronous rectifier BUCK converter are all turned off; NMOS tube Q5 in the second-stage current-type push-pull isolation converter is turned on, and NMOS tube Q4 is turned off; Ns1 winding and Ns2 winding of power transformer T1 in the two-stage series bridge voltage doubler rectifier circuit work in the positive half cycle, rectifier diodes V1 and V3 are turned on, and rectifier diodes V2 and V4 are turned off. At this time, the current flowing through the filter inductor L1 is freewheeling through the body diode of the NMOS tube Q3, and the inductor current decreases linearly.

[0081] Stage 13 [T11-T12]: In the first-stage frequency-doubling synchronous rectifier BUCK converter, N MOS tube Q3 is turned on, and N MOS tube Q1 and N MOS tube Q2 are turned off; in the second-stage current-type push-pull isolation converter, N MOS tube Q5 is turned on, and N MOS tube Q4 is turned off; in the two-stage series bridge voltage-doubling rectifier circuit, the Ns1 winding and Ns2 winding of the power transformer T1 work in the positive half cycle, the rectifier diodes V1 and V3 are turned on, and the rectifier diodes V2 and V4 are turned off. At this time, the current flowing through the filter inductor L1 is continued through the N MOS tube Q3, and the inductor current decreases linearly.

[0082] During the entire period T0-T12, the first-stage frequency-doubled synchronous rectification BUCK converter runs for two cycles, and the second-stage current-source push-pull isolation converter runs for one cycle. The operating frequency of the first-stage frequency-doubled synchronous rectification BUCK converter is twice that of the second-stage current-source push-pull isolation converter.

[0083] Example 5

[0084] A radio frequency ion electric propulsion screen grid power supply circuit has a triple overcurrent protection mechanism.

[0085] The working current of the thruster screen grid reaches or exceeds the maximum output current of the power supply due to the change of the load impedance of the thruster screen grid during the operation of the thruster. When the output current of the screen grid power supply is less than the set maximum output current, the power supply operates in the voltage loop mode to achieve constant voltage and stable output. When the load impedance of the thruster screen grid changes and causes its working current to reach or exceed the maximum output current of the power supply, the screen grid power supply quickly switches from the voltage loop working mode to the current loop working mode to achieve the maximum output current and constant current stable output. The switching response time of the two working modes is about milliseconds. The screen grid power supply performs adaptive adjustment of the constant voltage and constant current dual output mode according to the load impedance of the thruster screen grid, thereby meeting the power supply requirements of the screen grid during the ignition and operation of the thruster, and ensuring the stability and reliability of the operation of the radio frequency ion propulsion system.

[0086] The filter inductor L1 in the first-stage frequency-doubled synchronous rectification BUCK converter directly provides input current for the second-stage current-type push-pull isolation converter. Due to the self-inductance and back-electromotive force characteristics of the inductor, the current flowing through the filter inductor L1 cannot change suddenly. Therefore, the circuit naturally has the characteristics of transient current suppression, and can effectively suppress the peak current for all abnormal conditions that may cause sudden changes in the inductor current, including the thruster screen grid ignition discharge to the acceleration grid, the sudden change of the screen grid load, the current surge caused by a single particle in space, and other abnormal conditions, to prevent the screen grid power supply and its power supply bus from being hit by abnormal surge current.

[0087] For the working condition where a transient large current is generated at the entrance of the screen grid power supply busbar. The primary current is detected in real time through the primary current sampling circuit of the screen grid power supply, and the primary current sampling signal is sent to the PWM pulse width modulation circuit, thereby realizing primary overcurrent protection. When the primary current of the power supply exceeds the set protection threshold, the PWM pulse width modulation circuit first reduces the duty cycle of the pulse width modulation output signal of the PWM pulse width controller to reduce the output voltage of the screen grid power supply, thereby reducing the output power of the power supply. If the primary overcurrent phenomenon of the power supply still exists, the output of the PWM pulse width controller is turned off to turn off the output voltage of the screen grid power supply. After the primary overcurrent phenomenon of the power supply disappears, the screen grid power supply output is automatically restored. The response time of this protection function is about hundreds of microseconds.

[0088] Through the coordination of the above triple overcurrent protection mechanisms, the working reliability and power supply stability of the screen grid power supply under all working conditions are improved, the robustness of the RF ion electric propulsion system is further improved, and it can self-recover after the abnormal working conditions are eliminated.

[0089] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

Claims

1. A radio frequency ion electric propulsion screen grid power supply circuit, characterized in that: It includes an input filter capacitor Cin, a primary current sampling circuit, a first-stage frequency doubling synchronous rectification BUCK converter, a second-stage current type push-pull isolation converter, a two-stage series bridge voltage doubling rectifier circuit, an output voltage sampling circuit, and an output current sampling circuit. The two-stage series bridge voltage doubling rectifier circuit, the output current sampling circuit, and the output voltage sampling circuit are connected in sequence, and the output voltage sampling circuit is used to connect to the thruster screen grid load; The first-stage frequency-doubling synchronous rectification BUCK converter, the second-stage current-type push-pull isolation converter, and the two-stage series bridge voltage-doubling rectification circuit are connected via a power transformer T1.

2. The radio frequency ion electric propulsion screen grid power supply circuit according to claim 1, characterized in that: The primary current sampling circuit includes a current transformer T2, a magnetic reset resistor R1, a filter capacitor C5, a signal output diode V5, and a current-voltage signal conversion resistor R2; Pin 1 of the current transformer T2 is connected to one end of the input filter capacitor Cin and to the positive power supply line Vin+, pin 2 of the current transformer T2 is connected to the first-stage frequency-doubling synchronous rectification BUCK converter, pin 3 of the current transformer T2 is connected to the anode of the signal output diode V5, and pin 4 of the current transformer T2 is connected to the power supply ground CGnd of the PWM pulse width modulation circuit. The magnetic reset resistor R1 is connected in parallel with the filter capacitor C5, one end of which is connected to pin 3 of the current transformer T2, and the other end is connected to pin 4 of the current transformer T2. The anode of the signal output diode V5 is connected to pin 3 of the current transformer T2, and the cathode is connected to the primary current sampling signal IS. One end of the current-voltage signal conversion resistor R2 is connected to the primary current sampling signal IS, and the other end is connected to the power supply ground CGnd of the PWM pulse width modulation circuit.

3. The radio frequency ion electric propulsion screen grid power supply circuit according to claim 2, characterized in that: The first-stage frequency-doubled synchronous rectification BUCK converter includes an N MOS tube Q1, an N MOS tube Q2, an N MOS tube Q3 and a filter inductor L1; The drain of the N MOS tube Q1 is connected to the drain of the N MOS tube Q2 and connected to the 2nd pin of the current transformer T2. The source of the N MOS tube Q1 is connected to the source of the N MOS tube Q2 and connected to the drain of the N MOS tube Q3. The drain of the N MOS tube Q3 is also connected to one end of the filter inductor L1. The source of the N MOS tube Q3 is connected to the other end of the input filter capacitor Cin and connected to the power supply return line VinGnd. The other end of the filter inductor L1 is connected to the power transformer T1. The gate of the N MOS tube Q1 is connected to the first drive signal V Q1gs The gate of N MOS tube Q2 is connected to the second driving signal V Q2gs The gate of N MOS tube Q3 is connected to the third driving signal V Q3gs .

4. The radio frequency ion electric propulsion screen grid power supply circuit according to claim 1, characterized in that: Pins 1, 3, 5 and 7 of the power transformer T1 are the same-named terminals, and pins 2, 4, 6 and 8 are the same-named terminals. Pins 2 and 3 of the power transformer T1 are connected to the first-stage frequency-doubling synchronous rectification BUCK converter, and pins 1 and 4 are connected to the second-stage current-type push-pull isolation converter; The second-stage current-type push-pull isolation converter includes an N MOS transistor Q4 and an N MOS transistor Q5. The drain of the N MOS transistor Q4 is connected to the pin 1 of the power transformer T1, the source of the N MOS transistor Q4 is connected to the power supply return line VinGnd, and the gate of the N MOS transistor Q4 is connected to the fourth drive signal V Q4gs The drain of the N MOS tube Q5 is connected to the 4th pin of the power transformer T1, the source of the N MOS tube Q5 is connected to the power supply return line VinGnd, and the gate of the N MOS tube Q5 is connected to the fifth drive signal V Q5gs .

5. The radio frequency ion electric propulsion screen grid power supply circuit according to claim 4, characterized in that: The two-stage series bridge voltage doubler rectifier circuit includes a rectifier diode V1, a rectifier diode V2, a rectifier diode V3, a rectifier diode V4, a capacitor C1, a capacitor C2, a capacitor C3 and a capacitor C4; The anode of the rectifier diode V1 is connected to pin 5 of the power transformer T1, the cathode is connected to one end of the capacitor C1 and the positive power supply terminal Vout+ of the power supply output, and the other end of the capacitor C1 is connected to pin 6 of the power transformer T1; the cathode of the rectifier diode V2 is connected to pin 5 of the power transformer T1, the anode is connected to one end of the capacitor C2 and the cathode of the rectifier diode V3, and the other end of the capacitor C2 is connected to pin 6 of the power transformer T1; the anode of the rectifier diode V3 is connected to pin 7 of the power transformer T1, the cathode is connected to one end of the capacitor C3, and the other end of the capacitor C3 is connected to pin 8 of the power transformer T1; the cathode of the rectifier diode V4 is connected to pin 7 of the power transformer T1, the anode is connected to one end of the capacitor C4 and one end of the output current sampling circuit, and the other end of the capacitor C4 is connected to pin 8 of the power transformer T1.

6. The radio frequency ion electric propulsion screen grid power supply circuit according to claim 5, characterized in that: One end of the output voltage sampling circuit is connected to the positive terminal Vout+ of the power supply output, and the other end is connected to the power supply output ground line VoutGnd; the output voltage sampling circuit converts the power supply output voltage signal into an output voltage sampling signal Vcy.

7. The radio frequency ion electric propulsion screen grid power supply circuit according to claim 6, characterized in that: One end of the output current sampling circuit is connected to the anode of the rectifier diode V4, and the other end is connected to the power supply output ground line VoutGnd.

8. A radio frequency ion electric propulsion screen grid power supply control circuit, based on the radio frequency ion electric propulsion screen grid power supply power circuit according to any one of claims 1 to 7, characterized in that: It includes an output voltage PID negative feedback control circuit, an output current PID negative feedback control circuit, a feedback signal comparison circuit, a PWM pulse width modulation circuit, and an isolation drive circuit; The output voltage PID negative feedback control circuit receives the output voltage sampling signal Vcy from the output voltage sampling circuit, compares it with the output voltage reference signal Vset at the in-phase terminal of the operational amplifier, performs a negative feedback PID loop operation, and forms an output voltage feedback signal; The output current PID negative feedback control circuit receives the output current sampling signal Icy from the output current sampling circuit, compares it with the output current reference signal Iset at the same phase end of the operational amplifier, performs negative feedback PID loop operation, and forms an output current feedback signal.

9. The radio frequency ion electric propulsion screen grid power supply control circuit according to claim 8, characterized in that: The feedback signal comparison circuit includes a diode V6 and a diode V7. The cathode of the diode V6 is connected to the output voltage PID negative feedback control circuit, the anode is connected to the anode of the diode V7 and is connected to the PWM pulse width modulation circuit, and the cathode of the diode V7 is connected to the output current PID negative feedback control circuit.

10. The radio frequency ion electric propulsion screen grid power supply control circuit according to claim 9, characterized in that: The isolation driving circuit outputs the pulse width modulation output signal output by the PWM pulse width modulation circuit through the driving transformer to output the first driving signal V Q1gs , the second driving signal V Q2gs , the third driving signal V Q3gs , the fourth driving signal V Q4gs , the fifth driving signal V Q5gs .

Images