Surge eliminating circuit capable of being used for satellite-borne refrigerator power supply input port

Abstract

The invention provides a surge eliminating circuit capable of being used for a satellite-borne refrigerator power supply input port. A carrier wave generating circuit generates a fixed-frequency periodic carrier wave; the modulating wave generating circuit generates output voltage which rises according to an exponential rule through charging and discharging and serves as a modulating wave. The comparison driving circuit compares the periodic carrier waves with the modulation waves rising according to the exponential law to generate a pulse sequence with the duty ratio gradually increased, the pulse sequence is applied to a grid electrode of the surge suppression MOS tube, and then the surge suppression MOS tube is controlled to slowly charge an L-C array at the rear stage of a satellite-borne refrigerator power supply. According to the invention, the surge current at the start-up moment can be suppressed, and the surge current impact of the L-C array on the bus at the start-up moment is reduced to the greatest extent.

Description

Technical Field

[0001] The invention belongs to the technical field of power electronics, and in particular relates to a surge elimination circuit that can be used for a power input port of a satellite-borne refrigerator. Background Art

[0002] As a special power source, refrigerator power has a wide range of applications and broad prospects in various fields. With the development of science and technology, satellite refrigerator power has been developed towards high energy density and high efficiency. In response to this requirement, this application proposes a technical solution that uses the switching state of MOS tubes to suppress bus surge current. Summary of the invention

[0003] In view of this, the present invention provides a surge elimination circuit that can be used for the power input port of a satellite-borne refrigerator, which suppresses the surge current at the moment of startup and minimizes the surge current impact of the LC array on the bus at the moment of startup. It is mainly used in power distribution occasions where the power supply or port contains a large filter capacitor and the impact of the surge current on the bus needs to be reduced.

[0004] In order to solve the above technical problems, the present invention is implemented as follows.

[0005] A surge elimination circuit that can be used for a power input port of a satellite-borne refrigerator comprises: a carrier wave generation circuit, a modulation wave generation circuit, a comparison drive circuit and a surge suppression MOS tube;

[0006] The carrier generating circuit generates a periodic carrier with a fixed frequency;

[0007] The modulation wave generating circuit uses an RC circuit to generate a capacitor voltage that rises exponentially from 0 as a modulation wave when the onboard refrigerator power is turned on.

[0008] The comparison driving circuit compares the periodic carrier wave and the modulation wave that rises exponentially, and generates a series of pulse sequences with gradually increasing duty cycles. The pulse sequences are applied to the gate of the surge suppression MOS tube, thereby driving the conduction duty cycle of the surge suppression MOS tube to gradually increase from 0.

[0009] The surge suppression MOS tube is connected to the LC array of the back stage of the satellite refrigerator power supply. When the surge suppression MOS tube is turned on, the capacitor C1 in the LC array is charged. According to the gradual increase of the duty cycle of the surge suppression MOS tube (4), the LC array is gradually charged.

[0010] Preferably, a freewheeling diode V1 is connected between the surge suppression MOS tube and the LC array.

[0011] Preferably, the carrier generating circuit includes a first RC circuit consisting of a hysteresis comparator N1, a capacitor C3 and a resistor R4, and a voltage-dividing resistor; the resistor R4 is connected between the output terminal and the inverting input terminal of the hysteresis comparator N1, and the capacitor C4 is connected between the inverting input terminal of the hysteresis comparator N1 and the ground GND; the non-phase input terminal of the hysteresis comparator N1 is connected to the auxiliary power supply through the resistor R2; the voltage-dividing resistors R3 and R5 are connected between the non-phase input terminal of the hysteresis comparator N1 and the ground; by utilizing the repeated charging and discharging process of the first RC circuit, the output side of the hysteresis comparator N1 is flipped back and forth to generate a periodic carrier to generate a periodic carrier input comparison drive circuit.

[0012] Preferably, the modulation wave generating circuit is implemented by a second RC circuit composed of a capacitor C2 and a resistor R1; the resistor R1 and the capacitor C2 are connected in series between the auxiliary power supply and the ground GND; the connection point of the resistor R1 and the capacitor C2 serves as the output end; after the power is turned on, the capacitor C2 is charged through the resistor R1, and the voltage across the capacitor C2 rises exponentially, and the rising voltage is output through the output end and applied to the comparison drive circuit as a modulation wave.

[0013] Preferably, the comparison driving circuit is composed of a comparator N2 and a resistor R7; the periodic carrier is connected to the inverting input terminal of the comparator N2, and the modulation wave is connected to the non-inverting input terminal of the comparator N2; the comparator N2 compares the periodic carrier and the modulation wave; as the modulation wave gradually increases, the output port of the comparator N2 outputs a series of pulse sequences with gradually increasing duty cycles, which are output to the surge suppression MOS tube.

[0014] Beneficial effects:

[0015] (1) The onboard refrigerator power supply is designed with a larger LC array in the back stage. The surge elimination circuit can use the inductance characteristics of the back stage LC array to make the surge elimination MOS tube work in a switching state, gradually increase the MOS tube conduction duty cycle, thereby achieving a gradual charging state, suppressing the surge current at the moment of startup, and minimizing the surge current impact of the LC array on the bus at the moment of startup.

[0016] (2) MOS tube has low heat loss and reliable operation.

[0017] (3) At the same time, there is no need to increase the starting resistance or use the variable resistance area of ​​the MOS tube to achieve surge elimination. Compared with the traditional surge elimination circuit, the circuit has high efficiency and reliable operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The invention discloses a surge elimination circuit component module which can be used for a power input port of a satellite-borne refrigerator.

[0019] Figure 2 The present invention is a circuit diagram of a surge elimination circuit that can be used for a power input port of a satellite-borne refrigerator. DETAILED DESCRIPTION

[0020] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0021] In the power supply system for refrigerators, in order to suppress the second harmonic current generated by the refrigerator from entering the DC bus, a large-capacity LC array (such as Figure 1 At the moment of power on, the busbar will charge the LC array, resulting in a large surge current, which will impact the busbar. In order to suppress the surge current at the moment of power on, the present invention is designed as follows Figure 1 The surge suppression circuit shown.

[0022] The design idea of ​​the surge suppression circuit of the present invention is: at the moment of starting up the onboard refrigerator, the surge current at the moment of starting up is suppressed by controlling the on-duty cycle of the surge MOS tube to gradually increase from zero until it is normally open, thereby minimizing the surge current impact of the LC array on the bus at the moment of starting up.

[0023] The specific method is to use a periodic high-frequency carrier and modulation wave comparison method, and apply a driving signal with a duty cycle gradually increasing from zero to a constant high level to the gate of the surge suppression MOS tube during the startup process of the on-board refrigerator power supply, so as to control the surge suppression MOS tube to slowly charge the LC array of the subsequent stage of the on-board refrigerator power supply to achieve the purpose of surge elimination; at the same time, in order to ensure the continuity of the inductor L1 current during the shutdown period of the surge suppression MOS tube, the inductor L1 freewheeling diode is designed.

[0024] Figure 1 FIG. 2 shows a functional block diagram of a surge elimination circuit of the present invention that can be used at a power input port of a satellite-borne refrigerator. Figure 1 As shown, the surge elimination circuit includes a carrier generation circuit 1, a modulation wave generation circuit 2, a comparison drive circuit 3, and a surge suppression MOS tube 4.

[0025] The carrier generating circuit 1 generates a periodic carrier with a fixed frequency;

[0026] The modulation wave generating circuit 2 uses an RC circuit to generate a capacitor voltage that rises from 0 according to an exponential law when the onboard refrigerator power is turned on, and uses this as a modulation wave;

[0027] The comparison driving circuit 3 compares the periodic carrier wave and the modulation wave rising according to the exponential law, and generates a series of pulse sequences with gradually increasing duty cycles, which are applied to the gate of the surge suppression MOS tube 4, thereby driving the surge suppression MOS tube 4 to gradually increase its conduction duty cycle from 0;

[0028] The surge suppression MOS tube 4 is connected to the LC array of the subsequent stage of the satellite refrigerator power supply. When the surge suppression MOS tube 4 is turned on, the capacitor C1 in the LC array is charged; according to the gradual increase of the duty cycle of the surge suppression MOS tube 4, the LC array is gradually charged.

[0029] The working principle of the surge elimination circuit is as follows: during the power-on process, the carrier generation circuit generates a fixed-frequency periodic carrier; the modulation wave generation circuit generates a modulation wave whose voltage rises exponentially; during the power-on process, the modulation wave is compared with the carrier to generate a pulse sequence with a gradually increasing duty cycle, which is applied to the gate of the surge suppression MOS tube as a driving signal to control the on and off of the surge suppression MOS tube; the duty cycle of the driving signal gradually increases, the on time gradually increases, and the charging of the subsequent LC array gradually increases, so the charging of the subsequent LC array is slowly increased, ensuring that no large surge current is generated when the subsequent capacitor is charged, so as to achieve the purpose of suppressing the surge current. When the capacitor in the LC array is fully charged, the MOS tube will be normally on, and the charging process ends.

[0030] Figure 2 This is a specific circuit structure of a surge elimination circuit that can be used for the power input port of a satellite-borne refrigerator. Figure 2 As shown,

[0031] The carrier generating circuit 1 comprises a hysteresis comparator N1, a first RC circuit, a voltage-dividing resistor, and an input resistor R2; the first RC circuit is composed of a capacitor C3 and a resistor R4. The resistor R4 is connected between the output terminal (pin 7) and the inverting input terminal (pin 6) of the hysteresis comparator N1, and the capacitor C3 is connected between the inverting input terminal of the hysteresis comparator N1 and the ground GND; the positive input terminal (pin 5) of the hysteresis comparator N1 is connected to a 12V auxiliary power supply through an input resistor R2; the positive input terminal of the hysteresis comparator N1 is further connected to the ground GND with voltage-dividing resistors R3 and R5, R5 is connected between the output terminal and the positive input terminal of the hysteresis comparator N1, and R3 is connected to the ground GND.

[0032] By using the repeated charging and discharging process of the first RC circuit, the output side of the hysteresis comparator N1 is reversed back and forth, generating a periodic carrier and inputting the periodic carrier into the comparison driving circuit 3. Specifically, assuming that at a certain moment, the hysteresis comparator N1 outputs a high level, the capacitor C3 will be charged through the resistor R4. In this process, the voltage at the inverting input terminal of the hysteresis comparator N1 will gradually increase. Once the voltage value exceeds the voltage at the non-inverting input terminal of the hysteresis comparator N1, the comparator will be reversed, and the output of the hysteresis comparator N1 will change from a high level to a low level. From the voltage division relationship, it can be seen that when the output of the operational amplifier changes to a low level, the voltage at its non-inverting input terminal will decrease accordingly. At the same time, the capacitor C3 will be discharged through the resistor R4, and the voltage at the inverting input terminal will gradually decrease. When the voltage drops to a level lower than the voltage at the non-inverting input terminal of the operational amplifier, the output side of the comparator will be reversed again, and the comparator will be reversed back and forth in this way to generate a periodic carrier.

[0033] The modulation wave generating circuit 2 is implemented by a second RC circuit. The second RC circuit is composed of a capacitor C2 and a resistor R1. The resistor R1 and the capacitor C2 are connected in series between the 12V auxiliary power supply and the ground GND; the connection point of the resistor R1 and the capacitor C2 is used as the output terminal; after the onboard refrigerator power supply is turned on, the capacitor C2 is charged through the resistor R1, and the voltage across the capacitor C2 starts to rise from 0 according to the exponential law. The rising voltage is output through the output terminal and applied to the comparison drive circuit as a modulation wave.

[0034] The comparison driving circuit 3 is composed of a comparator N2 and a resistor R7; the periodic carrier is connected to the inverting input terminal (pin 6) of the comparator N2, and the modulation wave is connected to the non-inverting input terminal (pin 5) of the comparator N2; the comparator N2 compares the periodic carrier and the modulation wave. After the power is turned on, as the modulation wave gradually increases, the output port of the comparator N2 finally outputs a series of pulse sequences with gradually increasing duty cycles, thereby driving the on-duty cycle of the surge suppression MOS tube to gradually increase from 0, thereby gradually charging the subsequent LC array to ensure that the subsequent capacitor will not generate a large surge current when charging, so as to suppress the surge current.

[0035] In a preferred embodiment, in order to ensure the continuity of the inductor current during the MOS tube turn-off phase, a freewheeling diode V1 is connected between the surge suppression MOS tube 4 and the LC array.

[0036] The above specific embodiments only describe the design principle of the present invention. The shapes and names of the components in the description may be different and are not limited. Therefore, those skilled in the art in the field of the present invention may modify or replace the technical solutions recorded in the above embodiments; and these modifications and replacements do not deviate from the creative purpose and technical solutions of the present invention and should all fall within the protection scope of the present invention.

Claims

1. A surge elimination circuit that can be used for the power input port of a satellite-borne refrigerator, characterized in that: include: A carrier wave generating circuit (1), a modulation wave generating circuit (2), a comparison driving circuit (3) and a surge suppression MOS tube (4); The carrier generating circuit (1) generates a periodic carrier with a fixed frequency; The modulation wave generating circuit (2) uses an RC circuit to generate a capacitor voltage that rises exponentially from 0 as a modulation wave when the onboard refrigerator power is turned on; The comparison driving circuit (3) compares the periodic carrier wave and the modulation wave that rises exponentially, and generates a series of pulse sequences with gradually increasing duty cycles, and applies the pulse sequences to the gate of the surge suppression MOS tube (4), thereby driving the surge suppression MOS tube (4) to gradually increase its conduction duty cycle from 0; The surge suppression MOS tube (4) is connected to the LC array of the rear stage of the satellite refrigerator power supply. When the surge suppression MOS tube (4) is turned on, the capacitor C1 in the LC array is charged; according to the gradual increase of the duty cycle of the surge suppression MOS tube (4), the LC array is gradually charged.

2. The surge elimination circuit according to claim 1, characterized in that: A freewheeling diode V1 is connected between the surge suppression MOS tube (4) and the LC array.

3. The surge elimination circuit according to claim 1 or 2, characterized in that: The carrier generating circuit (1) comprises a hysteresis comparator N1, a first RC circuit composed of a capacitor C3 and a resistor R4, and a voltage dividing resistor; the resistor R4 is connected between the output end and the inverting input end of the hysteresis comparator N1, and the capacitor C4 is connected between the inverting input end of the hysteresis comparator N1 and the ground GND; the positive input end of the hysteresis comparator N1 is connected to an auxiliary power supply through a resistor R2; the voltage dividing resistors R3 and R5 are connected between the positive input end of the hysteresis comparator N1 and the ground; by using the repeated charging and discharging process of the first RC circuit, the output side of the hysteresis comparator N1 is flipped back and forth to generate a periodic carrier and generate a periodic carrier input comparison drive circuit (3).

4. The surge elimination circuit according to claim 1 or 2, characterized in that: The modulation wave generating circuit (2) is implemented by a second RC circuit composed of a capacitor C2 and a resistor R1; the resistor R1 and the capacitor C2 are connected in series between the auxiliary power supply and the ground GND; the connection point between the resistor R1 and the capacitor C2 serves as an output terminal; after the power supply is turned on, the capacitor C2 is charged through the resistor R1, and the voltage across the capacitor C2 rises according to an exponential law. The rising voltage is output through the output terminal and applied to the comparison drive circuit (3) as a modulation wave.

5. The surge elimination circuit according to claim 1 or 2, characterized in that: The comparison drive circuit (3) is composed of a comparator N2 and a resistor R7; a periodic carrier wave is connected to the inverting input terminal of the comparator N2, and a modulation wave is connected to the non-inverting input terminal of the comparator N2; the comparator N2 compares the periodic carrier wave and the modulation wave; as the modulation wave gradually increases, the output port of the comparator N2 outputs a series of pulse sequences with gradually increasing duty cycles, which are output to the surge suppression MOS tube (4).

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