Circuit and method for limiting short-circuit impact current through SSPC

Abstract

The invention discloses a circuit and method for limiting short-circuit impact current through SSPC, and relates to the technical field of aviation power distribution. The invention provides a hardware circuit for limiting short-circuit impact current through SSPC. The hardware circuit comprises a control loop and a power loop. The control loop converts a current signal of the power loop into a voltage signal through a sampling resistor, then the voltage signal is reasonably amplified to serve as a comparison point of the rear-end comparison circuit, the comparison circuit generates a threshold signal and transmits the threshold signal to the control circuit, and the control circuit outputs a driving signal to the driving circuit to control on-off of the MOS tube. The power loop comprises a main loop MOS tube switching circuit and an auxiliary loop MOS tube switching circuit, when the product works normally, the main loop is switched on, and the auxiliary loop is switched off; when short circuit occurs, the main loop is switched off, the auxiliary loop is switched on, and the purpose of limiting short-circuit impact current is achieved through the series current-limiting resistor.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation power distribution system, and in particular relates to a circuit and method for limiting short-circuit impact current of SSPC. Background Art

[0002] Since the 1980s, the rapid development of MOSFET technology using Si materials has attracted widespread attention to this new generation of power devices. At present, the 28V solid-state power controller circuit based on MOSFET has become mature. Due to the relatively low 28V voltage, the power margin of the selected MOSFET is large enough. Generally, no auxiliary circuit is designed in the circuit, but a single MOSFET is used to limit the short circuit. During the short circuit or capacitive load process, the self-current limiting of the MOSFET is completed in a relatively short time. Due to the limited current limiting capability of the MOSFET, the capacitive load current limiting process needs to be released after the current limiting, resulting in a current shock. This current shock is related to factors such as the response time of the solid-state power controller, the power supply capability, and the cable impedance. Therefore, the peak value of the current shock is somewhat uncontrollable during the entire process. Summary of the invention

[0003] The problem to be solved by the present invention is to optimize the existing 28V SSPC hardware circuit, adopt common circuit components, and provide a SSPC hardware circuit for limiting short-circuit impulse current, thereby achieving the purpose of limiting short-circuit impulse current.

[0004] In view of this, according to one aspect of an embodiment of the present invention, a SSPC circuit for limiting short-circuit impulse current is provided, comprising: a control circuit, a power circuit and a current acquisition circuit, wherein the input end of the control circuit is a voltage signal AMP and QGND converted from the current signal of the power circuit through a sampling resistor R2, and the output end is a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2;

[0005] The current acquisition circuit also includes a first comparison circuit, a second comparison circuit, a control circuit and a drive circuit, wherein the input end of the current acquisition circuit is the signals AMP and QGND at both ends of the sampling resistor R2, and the output end is the comparison voltage U; the input end of the first comparison circuit is the comparison voltage U and the threshold voltage U1, and the output end is the comparison signal ITRIP1; the input end of the second comparison circuit is the comparison voltage U and the threshold voltage U2, and the output end is the comparison signal ITRIP2; the input end of the control circuit is the comparison signal ITRIP1 and the comparison signal ITRIP2, and the output end is the drive signal DRVOUT; the input end of the drive circuit is the drive signal DRVOU T, the output end is the main loop drive signal DRV1 and the auxiliary loop drive signal DRV2; the drain D1 of the main loop MOS tube of the power circuit is electrically connected to 28V, the gate G1 is connected to the output end of the drive circuit, the source S1 is connected to one end of the sampling resistor R2, the other end of the sampling resistor R2 is connected to one end of the load M, the other end of the load M is connected to the 28V ground PGND, the 28V power input is connected to one end of the current limiting resistor R1, the other end of the current limiting resistor R1 is connected to the drain D2 of the auxiliary loop MOS, the gate G2 of the auxiliary loop MOS tube is connected to the output end of the drive circuit, and the source S2 is connected to the source level S1 of the main loop MOS tube.

[0006] Optionally, the resistance of the current limiting resistor R1 is 0.2-0.4Ω.

[0007] Optionally, the resistance of the sampling resistor R2 is 1-5 mΩ.

[0008] Optionally, the VDS voltage of the main loop MOS tube is 75V, the ID current is 300A, and the on-resistance RDS is 1.5mΩ.

[0009] Optionally, the VDS voltage of the auxiliary loop MOS tube is 100V, the ID current is 420A, and the on-resistance RDS is 2.6mΩ.

[0010] According to another aspect of an embodiment of the present invention, a method for limiting short-circuit impulse current using a SSPC is provided, based on any of the above circuits, comprising:

[0011] The control circuit receives the comparison signal ITRIP1 and the comparison signal ITRIP2, and sends a drive signal DRVOUT. The drive circuit receives the drive signal DRVOUT sent by the control circuit, and sends a main circuit drive signal DRV1 to the main circuit MOS tube to drive the main circuit and the auxiliary circuit MOS tube to turn on and off; sends an auxiliary circuit drive signal DRV2 to the auxiliary circuit MOS tube to drive the auxiliary circuit MOS tube to turn on and off;

[0012] When the load M is in a normal working state, the load current I is the rated current, and the comparison voltage U is converted into the rated voltage by the current acquisition circuit, and does not reach the threshold voltage U1 of the first comparison circuit and the threshold voltage U2 of the second comparison circuit, the control circuit sends a drive signal DRVOUT, the drive circuit receives the drive signal DRVOUT sent by the control circuit, sends a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2, the main circuit MOS tube is turned on, and the auxiliary circuit MOS tube is turned on;

[0013] When the load is in a short-circuit state, the load current I starts to increase from 0 and is converted into a comparison voltage U through the current acquisition circuit. When the threshold voltage U1 of the comparison circuit 1 is triggered first, a comparison signal ITRIP1 is output, and the control circuit sends a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2. The main circuit MOS is turned off and the auxiliary circuit MOS is turned on. At this time, the current limiting resistor R1 in series with the auxiliary circuit limits the load current I to a constant value, thereby achieving the purpose of limiting the short-circuit current.

[0014] Optionally, the load current I continues to increase and is converted into a comparison voltage U through the current acquisition circuit. When the threshold voltage U2 of the comparison circuit 2 is triggered, a comparison signal ITRIP2 is output, and the control circuit sends a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2. The main circuit MOS is turned off, and the auxiliary circuit MOS is turned off after a delay of 2 to 4 ms, and the product reports a short circuit signal.

[0015] Optionally, when the load current I is the rated current, the comparison voltage U converted by the current acquisition circuit is the rated voltage, the threshold voltage U1 of the comparison circuit 1 is 3-5 times the rated voltage; the threshold voltage U2 of the comparison circuit 2 is 10 times the rated voltage.

[0016] The present invention ensures that the impact current during the short-circuit process is controllable through the auxiliary circuit current limiting resistor, and avoids the impact of the short-circuit impact current being too high on the power grid. The present invention is applicable to a hardware circuit for SSPC to limit the short-circuit impact current. The circuit is simple and reliable. By switching to the auxiliary circuit when the impact current is low, the short-circuit current is controllable and the stability of the input power supply is guaranteed. When the short-circuit impact current is small, the auxiliary circuit is switched to limit the current to achieve the purpose of limiting the short-circuit impact current, and the impact on the power grid is small. The control circuit converts the current signal of the power circuit into a voltage signal through the sampling resistor, and then reasonably amplifies it as the comparison point of the back-end comparison circuit. The comparison circuit generates a threshold signal and transmits it to the control circuit. The control circuit outputs a drive signal to the drive circuit to control the on and off of the MOS tube. The power circuit includes a main circuit MOS tube switch circuit and an auxiliary circuit MOS tube switch circuit. When the product works normally, the main circuit is turned on and the auxiliary circuit is turned off; when a short circuit occurs, the main circuit is turned off and the auxiliary circuit is turned on. The purpose of limiting the short-circuit impact current is achieved by connecting a series current limiting resistor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a hardware circuit cross-linking block diagram of a 28V SSPC for limiting short-circuit impact current according to the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 are within the scope of protection of the present invention.

[0019] According to one aspect of an embodiment of the present invention, a SSPC circuit for limiting short-circuit impulse current is provided, comprising: a control circuit, a power circuit and a current acquisition circuit, wherein the input end of the control circuit is a voltage signal AMP and QGND converted from a current signal of the power circuit through a sampling resistor R2, and the output end is a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2;

[0020] The current acquisition circuit also includes a first comparison circuit, a second comparison circuit, a control circuit and a drive circuit, wherein the input end of the current acquisition circuit is the signals AMP and QGND at both ends of the sampling resistor R2, and the output end is the comparison voltage U; the input end of the first comparison circuit is the comparison voltage U and the threshold voltage U1, and the output end is the comparison signal ITRIP1; the input end of the second comparison circuit is the comparison voltage U and the threshold voltage U2, and the output end is the comparison signal ITRIP2; the input end of the control circuit is the comparison signal ITRIP1 and the comparison signal ITRIP2, and the output end is the drive signal DRVOUT; the input end of the drive circuit is the drive signal DRVOU T, the output end is the main loop drive signal DRV1 and the auxiliary loop drive signal DRV2; the drain D1 of the main loop MOS tube of the power circuit is electrically connected to 28V, the gate G1 is connected to the output end of the drive circuit, the source S1 is connected to one end of the sampling resistor R2, the other end of the sampling resistor R2 is connected to one end of the load M, the other end of the load M is connected to the 28V ground PGND, the 28V power input is connected to one end of the current limiting resistor R1, the other end of the current limiting resistor R1 is connected to the drain D2 of the auxiliary loop MOS, the gate G2 of the auxiliary loop MOS tube is connected to the output end of the drive circuit, and the source S2 is connected to the source level S1 of the main loop MOS tube.

[0021] Furthermore, the resistance of the current limiting resistor R1 is 0.2-0.4Ω.

[0022] Furthermore, the resistance of the sampling resistor R2 is 1-5 mΩ.

[0023] Furthermore, the VDS voltage of the main loop MOS tube is 75V, the ID current is 300A, and the on-resistance RDS is 1.5mΩ.

[0024] Furthermore, the VDS voltage of the auxiliary loop MOS tube is 100V, the ID current is 420A, and the on-resistance RDS is 2.6mΩ.

[0025] According to another aspect of an embodiment of the present invention, a method for limiting short-circuit impulse current using a SSPC is provided, based on any of the above circuits, comprising:

[0026] The control circuit receives the comparison signal ITRIP1 and the comparison signal ITRIP2, and sends a drive signal DRVOUT. The drive circuit receives the drive signal DRVOUT sent by the control circuit, and sends a main circuit drive signal DRV1 to the main circuit MOS tube to drive the main circuit and the auxiliary circuit MOS tube to turn on and off; sends an auxiliary circuit drive signal DRV2 to the auxiliary circuit MOS tube to drive the auxiliary circuit MOS tube to turn on and off;

[0027] When the load M is in a normal working state, the load current I is the rated current, and the comparison voltage U is converted into the rated voltage by the current acquisition circuit, and does not reach the threshold voltage U1 of the first comparison circuit and the threshold voltage U2 of the second comparison circuit, the control circuit sends a drive signal DRVOUT, the drive circuit receives the drive signal DRVOUT sent by the control circuit, sends a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2, the main circuit MOS tube is turned on, and the auxiliary circuit MOS tube is turned on;

[0028] When the load is in a short-circuit state, the load current I starts to increase from 0 and is converted into a comparison voltage U through the current acquisition circuit. When the threshold voltage U1 of the comparison circuit 1 is triggered first, a comparison signal ITRIP1 is output, and the control circuit sends a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2. The main circuit MOS is turned off and the auxiliary circuit MOS is turned on. At this time, the current limiting resistor R1 in series with the auxiliary circuit limits the load current I to a constant value, thereby achieving the purpose of limiting the short-circuit current.

[0029] Furthermore, the load current I continues to increase and is converted into a comparison voltage U through the current acquisition circuit. When the threshold voltage U2 of the comparison circuit 2 is triggered, the comparison signal ITRIP2 is output, and the control circuit sends the main circuit drive signal DRV1 and the auxiliary circuit drive signal DRV2. The main circuit MOS is turned off, and the auxiliary circuit MOS is turned off after a delay of 2 to 4 ms, and the product reports a short circuit signal.

[0030] Furthermore, when the load current I is the rated current, the comparison voltage U converted by the current acquisition circuit is the rated voltage, and the threshold voltage U1 of the comparison circuit 1 is 3-5 times the rated voltage; the threshold voltage U2 of the comparison circuit 2 is 10 times the rated voltage.

[0031] Example 1

[0032] The purpose of the present invention can be achieved by the following technical solutions:

[0033] The hardware circuit of 28VSSPC to limit short-circuit impact current includes: control circuit and power circuit.

[0034] The input end of the control loop is the voltage signal AMP and QGND converted from the current signal of the power loop through the sampling resistor R2, and the output end is the main loop drive signal DRV1 and the auxiliary loop drive signal DRV2.

[0035] Furthermore, the control circuit includes a current acquisition circuit, a comparison circuit 1, a comparison circuit 2, a control circuit and a drive circuit, wherein:

[0036] The input end of the current acquisition circuit is the signals AMP and QGND at both ends of the sampling resistor R2, and the output end is the comparison voltage U1; the input end of the comparison circuit 1 is the comparison voltage U and the threshold voltage U1, and the output end is the comparison signal ITRIP1; the input end of the comparison circuit 2 is the comparison voltage U and the threshold voltage U2, and the output end is the comparison signal ITRIP2; the input end of the control circuit is the comparison signal ITRIP1 and the comparison signal ITRIP2, and the output end is the drive signal DRVOUT; the input end of the drive circuit is the drive signal DRVOUT, and the output end is the main loop drive signal DRV1 and the auxiliary loop drive signal DRV2.

[0037] In the power circuit, the drain D1 of the main circuit MOS tube is electrically connected to 28V, the gate G1 is connected to the output end of the drive circuit, the source S1 is connected to one end of the sampling resistor R2, the other end of the sampling resistor R2 is connected to one end of the load, and the other end of the load is connected to the 28V ground PGND.

[0038] The 28V power is connected to one end of the current limiting resistor R1, the other end of the current limiting resistor is connected to the drain D2 of the auxiliary loop MOS, the gate G2 of the auxiliary loop MOS is connected to the output end of the driving circuit, and the source S2 is connected to the source level S1 of the main loop MOS tube.

[0039] The main loop MOS tube receives the main loop drive signal DRV1, and the main loop MOS tube is normally turned on; the auxiliary loop MOS tube receives the auxiliary loop drive signal DRV2, and the auxiliary loop MOS tube is normally turned on.

[0040] Furthermore, the load current I of the power circuit is converted into a comparison voltage U1 through the sampling resistor R2, which is used as the input end of the subsequent comparison circuit.

[0041] Furthermore, in order to limit the short-circuit impact current, it is necessary to reasonably select the current limiting resistor R1.

[0042] Furthermore, the VDS voltage of the main loop MOS tube is 75V, the ID current is 300A, and the on-resistance RDS is 1.5mΩ; the VDS voltage of the auxiliary loop MOS tube is 100V, the ID current is 420A, and the on-resistance RDS is 2.6mΩ; the resistance value of the current limiting resistor R1 is 0.4Ω; and the resistance value of the sampling resistor R2 is 5mΩ.

[0043] Furthermore, when the load current I is the rated current, the comparison voltage U converted by the current acquisition circuit is the rated voltage, and the threshold voltage U1 of the comparison circuit 1 is 3-5 times the rated voltage; the threshold voltage U2 of the comparison circuit 2 is 10 times the rated voltage.

[0044] Example 2

[0045] like Figure 1 As shown, it is a hardware circuit cross-linking block diagram of the 28VSSPC short-circuit impact current limiting of the present invention, including a control circuit and a power circuit.

[0046] The control circuit includes a current acquisition circuit, a comparison circuit 1, a comparison circuit 2, a control circuit and a drive circuit, wherein:

[0047] The current acquisition circuit converts the load current I of the power circuit into a voltage signal U1 (U1=R2×I) through the sampling resistor R2, which is used as the input end of the subsequent comparison circuit 1 and the comparison circuit 2; the threshold voltage U1 of the comparison circuit 1 is 3.5 times the comparison voltage U; the threshold voltage of the comparison circuit 2 is 10 times the comparison voltage U.

[0048] The power circuit includes a main circuit MOS circuit and an auxiliary circuit MOS circuit, wherein:

[0049] The drain D1 of the main loop MOS tube is electrically connected to 28V, the gate G1 is connected to the output end of the drive circuit, the source S1 is connected to one end of the sampling resistor R2, the other end of the sampling resistor R2 is connected to one end of the load, and the other end of the load is connected to the 28V ground PGND. The 28V is electrically connected to one end of the current limiting resistor R1, the other end of the current limiting resistor is connected to the drain D2 of the auxiliary loop MOS, the gate G2 of the auxiliary loop MOS is connected to the output end of the drive circuit, and the source S2 is connected to the source S1 of the main loop MOS tube. The main loop MOS tube receives the main loop drive signal DRV1, and the main loop MOS tube is normally turned on; the auxiliary loop MOS tube receives the auxiliary loop drive signal DRV2, and the auxiliary loop MOS tube is normally turned on.

[0050] When the load is in normal working state, the load current I is the rated current, and the comparison voltage U is converted into the rated voltage by the current acquisition circuit, and does not reach the threshold voltage U1 of the comparison circuit 1 and the threshold voltage U2 of the comparison circuit 2, the control circuit sends the main circuit drive signal DRV1 and the auxiliary circuit drive signal DRV2, the main circuit MOS is turned on, and the auxiliary circuit MOS is turned on;

[0051] When the load is in a short-circuit state, the load current I starts to increase from 0 and is converted into a comparison voltage U through the current acquisition circuit. When the threshold voltage U1 of the comparison circuit 1 is triggered first, a comparison signal ITRIP1 is output, and the control circuit sends a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2. The main circuit MOS is turned off and the auxiliary circuit MOS is turned on. At this time, the current limiting resistor R1 connected in series with the auxiliary circuit limits the load current I to a constant value, thereby achieving the purpose of limiting the short-circuit current. The current limiting resistor R1 is selected to be 0.4Ω, and the short-circuit current is limited to 70A.

[0052] The load current I continues to increase and is converted into a comparison voltage U through the current acquisition circuit. When the threshold voltage U2 of the comparison circuit 2 is triggered, the comparison signal ITRIP2 is output, and the control circuit sends the main circuit drive signal DRV1 and the auxiliary circuit drive signal DRV2. The main circuit MOS is turned off, and the auxiliary circuit MOS is turned off after a delay of 2ms, and the product reports a short circuit signal.

[0053] The above is only a specific embodiment of the present invention, and the present invention is described in detail. The unexplained part is a conventional technology. However, the protection scope of the present invention is not limited to this. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A SSPC circuit for limiting short-circuit impulse current, characterized in that: include: Control loop, power loop and current acquisition circuit, wherein the input end of the control loop is the voltage signal AMP and QGND converted by the current signal of the power loop through the sampling resistor R2, and the output end is the main loop drive signal DRV1 and the auxiliary loop drive signal DRV2; The current acquisition circuit also includes a first comparison circuit, a second comparison circuit, a control circuit and a drive circuit, wherein the input end of the current acquisition circuit is the signals AMP and QGND at both ends of the sampling resistor R2, and the output end is the comparison voltage U; The input terminal of the first comparison circuit is the comparison voltage U and the threshold voltage U1, and the output terminal is the comparison signal ITRIP1; The input terminal of the second comparison circuit is the comparison voltage U and the threshold voltage U2, and the output terminal is the comparison signal ITRIP2; The input end of the control circuit is the comparison signal ITRIP1 and the comparison signal ITRIP2, and the output end is the drive signal DRVOUT; The input end of the driving circuit is the driving signal DRVOUT, and the output end is the main circuit driving signal DRV1 and the auxiliary circuit driving signal DRV2; The drain D1 of the main loop MOS tube of the power circuit is electrically connected to 28V, the gate G1 is connected to the output end of the drive circuit, the source S1 is connected to one end of the sampling resistor R2, the other end of the sampling resistor R2 is connected to one end of the load M, and the other end of the load M is connected to the 28V ground PGND; The 28V power input is connected to one end of the current limiting resistor R1, the other end of the current limiting resistor R1 is connected to the drain D2 of the auxiliary loop MOS, the gate G2 of the auxiliary loop MOS tube is connected to the output end of the drive circuit, and the source S2 is connected to the source level S1 of the main loop MOS tube.

2. The circuit according to claim 1, characterized in that The resistance of the current limiting resistor R1 is 0.2~0.4Ω.

3. The circuit according to claim 1, characterized in that The resistance of the sampling resistor R2 is 1-5 mΩ.

4. The circuit according to claim 1, characterized in that The VDS voltage of the main circuit MOS tube is 75V, the ID current is 300A, and the on-resistance RDS is 1.5mΩ.

5. The circuit according to claim 1, characterized in that The VDS voltage of the auxiliary loop MOS tube is 100V, the ID current is 420A, and the on-resistance RDS is 2.6mΩ.

6. A method for limiting short-circuit impulse current of SSPC, characterized in that: Based on any circuit described in claims 1-5, comprising: The control circuit receives the comparison signal ITRIP1 and the comparison signal ITRIP2, and sends a drive signal DRVOUT. The drive circuit receives the drive signal DRVOUT sent by the control circuit, and sends a main circuit drive signal DRV1 to the main circuit MOS tube to drive the main circuit and the auxiliary circuit MOS tube to turn on and off; sends an auxiliary circuit drive signal DRV2 to the auxiliary circuit MOS tube to drive the auxiliary circuit MOS tube to turn on and off; When the load M is in a normal working state, the load current I is the rated current, and the comparison voltage U is converted to the rated voltage by the current acquisition circuit, and does not reach the threshold voltage U1 of the first comparison circuit and the threshold voltage U2 of the second comparison circuit. The control circuit sends a drive signal DRVOUT, and the drive circuit receives the drive signal DRVOUT sent by the control circuit, sends a main circuit drive signal DRV1 and an auxiliary circuit drive signal DRV2, and the main circuit MOS tube is turned on and the auxiliary circuit MOS tube is turned on; when the load is in a short-circuit state, the load current I increases from 0, and is converted to the comparison voltage U by the current acquisition circuit. When the threshold voltage U1 of the comparison circuit 1 is first triggered, the comparison signal ITRIP1 is output, and the control circuit sends the main circuit drive signal DRV1 and the auxiliary circuit drive signal DRV2, the main circuit MOS is turned off, and the auxiliary circuit MOS is turned on. At this time, the current limiting resistor R1 connected in series with the auxiliary circuit limits the load current I to a constant value, thereby achieving the purpose of limiting the short-circuit current.

7. The method according to claim 6, characterized in that The load current I continues to increase and is converted into a comparison voltage U through the current acquisition circuit. When the threshold voltage U2 of the comparison circuit 2 is triggered, the comparison signal ITRIP2 is output, and the control circuit sends the main circuit drive signal DRV1 and the auxiliary circuit drive signal DRV2. The main circuit MOS is turned off, and the auxiliary circuit MOS is turned off after a delay of 2 to 4 ms, and the product reports a short circuit signal.

8. The method according to claim 6, characterized in that When the load current I is the rated current, it is converted into a comparison voltage U as the rated voltage through the current acquisition circuit. The threshold voltage U1 of the comparison circuit 1 is 3-5 times the rated voltage; the threshold voltage U2 of the comparison circuit 2 is 10 times the rated voltage.

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