CN201571033U - Solid state power controller - Google Patents

Abstract

The utility model relates to a solid state power controller which is classified as a control circuit taking a microcontroller circuit as the core. The solid state power controller comprises the microcontroller circuit, a bias circuit, an isolating circuit, a tripping feedback circuit, an output feedback circuit, a constant-current circuit, a sampling circuit and an output part, and is characterized in that the output part comprises a power MOSFET (metal-oxide-semiconductor field-effect transistor), a self-locking circuit and a drive circuit consisting of a triode drive circuit and a rapid discharge circuit; the output of the self-locking circuit is connected with the drive circuit; and the output of the drive circuit is connected with the power MOSFET. The drive circuit has high power, so as to ensure that the power MOSFET is conducted and turned off quickly and reduce the switching power of the power MOSFET. The solid state power controller adopts brownout reset and self locking for overload and short circuit protection, and has the advantages of high intelligentized degree and reliable operation.

Description

Solid State Power Controller

Technical field

The utility model belongs to the field of industrial automation control and relates to a solid power controller.

Background technique

Solid State Power Controller (SSPC for short) is a combined component with intelligent functions, which includes the functions of solid state relay and overcurrent circuit breaker. The existing solid state relay has the advantages of small size, no contact, fast switching speed, strong shock and vibration resistance, and good resistance to harsh environments, but it is easy to cause damage to the solid state relay in the case of overload or short circuit; and overcurrent The circuit breaker has an internal mechanical linkage structure, metal contact contact, relatively weak shock and vibration resistance, and poor environmental adaptability.

Utility model content

The purpose of the utility model is to provide a solid power controller with a high degree of intelligence. The solid power controller works reliably and also has the protection function of overload and load short circuit.

The solid power controller provided by the utility model adopts the following technical scheme: it is composed of a microcontroller circuit, a bias circuit, an isolation circuit, a trip feedback circuit, an output feedback circuit, a constant current circuit, a sampling circuit and an output part, and the bias circuit , an isolation circuit, a tripping feedback circuit, an output feedback circuit, a constant current circuit, a sampling circuit and an output part connected with a microcontroller circuit, and it is characterized in that the output part is composed of a power field effect tube, a self-locking circuit and a triode drive circuit Composed of a driving circuit composed of a fast discharge circuit, the output of the self-locking circuit is connected to the driving circuit, and the output of the driving circuit is connected to a power field effect tube.

The triode drive circuit in the output part is composed of triode output photocoupler V1, NPN transistor V4, PNP transistor V2, voltage regulator tubes V6, V8, resistors R1-R4, resistors R6, R7, and capacitor C1. The discharge circuit is composed of NPN transistor V3, PNP transistor V5, and resistor R5. The control voltage signal U1 of the microcontroller circuit is input by the positive pole of the light-emitting tube of the photocoupler V1, and the negative pole of the light-emitting tube is grounded through the regulator tube V8. The resistor R1 Connected between the base and the grounded emitter of the light receiving tube of the photocoupler V1, its collector is connected to the base of the triode V2 through the parallel resistor R3 and capacitor C1, and the resistor R2 is connected between the base and the emitter of the triode V2, The collector of the transistor V2 is connected to the bases of the transistors V4 and V5, the collector of the transistor V3 is connected to the ground through the resistor R4; the emitters of the transistors V4 and V5 are common, the collector of the transistor V5 is connected to the ground through the resistor R5, and the resistors R6 and R7 are connected in series Between the emitters of the triodes V4 and V5 and the grid of the power field effect transistor V7, the regulator V6 is connected between the junction of the resistors R6 and R7 and the ground.

Described self-locking circuit is made up of bidirectional thyristor output type photocoupler V10, triode output type photocoupler V1, resistors R1, R8, voltage regulator tube V8, the bidirectional thyristor output type photocoupler V10 light-emitting tube The positive pole is connected to the trip protection pulse signal, the negative pole is grounded, one electrode of the triode triac is grounded, and the other electrode is connected to the positive pole of the triode output photocoupler V1 light-emitting tube through the resistor R8. Control signal, triode output photoelectric coupling The negative pole of the luminescent tube of device V1 is grounded through the voltage regulator tube V8, and the resistor R1 is connected between the base and the emitter of the light receiving tube of the triode output type photocoupler V1, and the collector of the light receiving tube outputs a driving signal to the driving circuit.

The sampling circuit is composed of a sampling resistor RS connected in series in the output circuit and an amplifying circuit. The sampling voltage signal of the sampling resistor RS is amplified by the amplifying circuit and then sent to the microcontroller circuit. The sampling resistor RS is attached to the ceramic DBC board.

The working principle of the solid power controller provided by the utility model is: the microcontroller circuit is the control core of the solid power controller, and the bias circuit and the DC/DC isolation circuit provide power to each unit circuit. When the input voltage signal is applied At this time, the signal is added to the microcontroller circuit through the constant current circuit, and the microcontroller circuit outputs a driving signal to drive the power field effect tube, so that the solid state power controller is turned on; when the input voltage signal is cut off, the solid state power controller is turned off. The microcontroller PIC always detects the output load status through the sampling resistor RS connected in series in the output circuit, and feeds back to the output status terminal to display the load working status. Overload and short circuit protection always detect the load current through the sampling resistor RS. When the current is overloaded, the overload information will be fed back to the microcontroller PIC circuit. The microcontroller circuit will delay according to the overload current. If the overload is not eliminated during the delay period, The microcontroller circuit will start the trip protection function of the system to turn off the output, and at the same time feed back the signal to the trip status terminal, and turn on the trip output (the same function as the auxiliary contact of the circuit breaker). The output power tube of the solid power controller in the output part uses a power field effect tube with low on-resistance; the drive circuit composed of a triode drive circuit and a fast discharge circuit is used, and the characteristic is that the power of the drive circuit is large, which ensures the power of the power MOSFET tube. The fast turn-on and fast turn-off of the power MOSFET reduce the switching power consumption of the power MOSFET and realize the reliable operation of the high-power MOSFET. A self-locking circuit connected to the drive circuit is set in the output part. The overload and short-circuit protection of the solid power controller adopts the self-locking mode of power-off reset, that is, after the overload or short-circuit protection action, the input voltage signal must be turned off. Reapply the input voltage signal again, and the solid state power controller can realize re-connecting the output again. Make solid power controller work more reliable. The sampling circuit is composed of a sampling resistor RS and an amplifying circuit connected in series in the output circuit. The sampling resistor RS is installed close to the ceramic DBC board, so that the heat generated by it can quickly pass through the ceramic DBC board, the copper base plate and the radiator path. Dispersed, the voltage consistency of the sampling signal is very good, which effectively avoids the influence of the heat increase of the sampling resistor on the resistance accuracy.

The solid power controller provided by the utility model adopts the microcontroller PIC as the core control circuit to complete the control, and has a high degree of intelligence, and the output power tube selects a power field effect tube with low conduction resistance; the load current adopts a resistance sampling method ; The overload and short circuit protection of the solid power controller adopts the self-locking method of power failure reset, the solid power controller works reliably, and at the same time, it also has the advantages of low power consumption and high control precision.

Description of drawings

Fig. 1 is the electrical principle block diagram of the solid power controller provided by the utility model;

Fig. 2 is the electrical schematic diagram of the embodiment of the driving circuit of the output part of the solid state power controller;

Fig. 3 is the electrical schematic diagram of the embodiment of the self-locking circuit of the output part of the solid state power controller;

Fig. 4 is the functional block diagram of the sampling circuit of the solid state power controller;

Fig. 5 is the electric schematic diagram of the amplification circuit embodiment in the sampling circuit of the solid state power controller;

Figure 6 is a structural diagram of the installation process of the sampling resistor of the solid power controller;

Figure 7 is a block diagram of the control principle of the solid-state power controller microcontroller.

Detailed ways

The implementation of the utility model and the various principles of each component of the solid state power controller will be described in detail below in conjunction with the accompanying drawings.

Figure 1 is an electrical block diagram of a solid state power controller. It can be seen from Figure 1 that the solid power controller provided by the utility model is a control circuit with a microcontroller circuit as the core, and consists of a microcontroller circuit, a bias circuit, an isolation circuit, a trip feedback circuit, an output feedback circuit, and a constant current circuit. , Sampling circuit and output part, bias circuit, isolation circuit, tripping feedback circuit, output feedback circuit, constant current circuit, sampling circuit and output part are connected with microcontroller circuit.

Microcontroller circuit is the core part of solid power controller design. Its main function is to realize the shutdown of the output circuit by processing the control input signal, reset input signal, and sampling signal; Detect and feed back to the trip status terminal and load status terminal at any time to display the load working status; and control the shutdown of a trip output (the same function as the auxiliary contact of the circuit breaker). When the solid-state power controller is in the protection state, the output can be re-connected by resetting the input voltage to a low level.

The block diagram of the control principle composed of microcontroller PIC is shown in Figure 7. When the solid-state power controller is overloaded or short-circuited, the signal obtained by the overload or short-circuit current through the sampling circuit, through the amplifying circuit, outputs a voltage signal proportional to the load current, and the A/D converter in the microcontroller PIC will sample to The analog voltage signal is converted into a digital signal, and the judgment of different tripping times under different overload or short-circuit currents is realized through the pre-programmed software program, and the driving circuit of the power output tube is controlled to achieve the purpose of shutting down the output; at the same time, a tripping state can be output signal or load switch status signal. Through the software programming of the microcontroller PIC, we can easily modify the trip current value and trip time, short-circuit current value and short-circuit time, and truly fully realize the intelligence of the solid-state power controller. The advantage is that the solid-state power control The intelligent level of the device is high, and the online modification program is realized. The program modification according to the trip current value and time required by different users can meet the requirements, which is convenient for production and debugging.

Fig. 2 is an electrical schematic diagram of an embodiment of the driving circuit of the output part of the solid state power controller. The triode driving circuit in the output part of the solid power controller is composed of triode output photocoupler V1, NPN transistor V4, PNP transistor V2, voltage regulator tubes V6, V8, resistors R1-R4, resistors R6, R7, and capacitor C1. The fast discharge circuit is composed of NPN transistor V3, PNP transistor V5, and resistor R5. The control voltage signal U1 of the microcontroller circuit is input by the positive pole of the light-emitting tube of the photocoupler V1, and the negative pole of the light-emitting tube is grounded through the voltage regulator tube V8. Resistor R1 is connected between the base and grounded emitter of photoelectric coupler V1, its collector is connected to the base of triode V2 through parallel resistor R3 and capacitor C1, and resistor R2 is connected to the base and emitter of triode V2 Between, the collector of the transistor V2 is connected to the bases of the transistors V4 and V5, the collector of the transistor V3 is grounded through the resistor R4; the emitters of the transistors V4 and V5 are common, the collector of the transistor V5 is grounded through the resistor R5, and the resistors R6 and R7 are connected in series It is connected between the emitters of transistors V4 and V5 and the gate of power field effect transistor V7, and the regulator tube V6 is connected between the junction of resistors R6 and R7 and the ground. The output stage of the drive circuit uses a triode drive circuit to directly drive the power MOSFET tube V7. When the input signal U1 is at a high level, the photocoupler transistor V1 is turned on, pin 5 is at a low level, the transistor V2 is turned on, the transistor V3 is turned off, the transistor V5 is turned off, the transistor V4 is turned on, and the driving voltage is output through the resistors R6 and R7. On the gate of the power MOSFET, the power MOSFET tube V7 is turned on; when the input signal U1 is at a low level, the photocoupler transistor V1 is turned off, pin 5 is at a high level, the transistor V2 is turned off, the transistor V3 is turned on, and the transistor V5 is turned on , the transistor V4 is cut off, and the charge on the gate of the power MOSFET is discharged through the fast discharge circuit composed of the NPN transistor V3, the PNP transistor V5, and the resistor R5, so that the power MOSFET V7 is quickly cut off and turned off. The advantage of this driving circuit is that the power of the driving circuit is large, which ensures fast turn-on and fast turn-off of the power MOSFET, reduces switching power consumption of the power MOSFET, and realizes reliable operation of the high-power MOSFET.

Fig. 3 is an electrical schematic diagram of an embodiment of the self-locking circuit of the output part of the solid state power controller. Referring to Figure 3, the self-locking circuit is composed of triac output photocoupler V10, triode output photocoupler V1, resistors R1, R8, voltage regulator V8, triac output photocoupler V10 light-emitting tube The positive electrode of the LED is connected to the tripping protection pulse signal U2, the negative electrode is grounded, one electrode of the bidirectional thyristor of the light-receiving tube is grounded, and the other electrode is connected to the positive electrode of the triode output photocoupler V1 light-emitting tube through the resistor R8. The control signal U1 is output by the triode. The negative pole of the photoelectric coupler V1 light-emitting tube is grounded through the voltage regulator tube V8, and the resistor R1 is connected between the base and the emitter of the photoelectric coupler V1 light-emitting tube of the triode output type, and the collector of the light-collecting tube outputs a driving signal to the driver circuit. The self-locking circuit and the driving circuit share the triode output photocoupler V1. In the self-locking protection circuit, a SCR output photocoupler is used. After the SCR is turned on, the current is maintained to maintain its conduction characteristics, and the bypass input control signal is used to turn off the control circuit. Realize tripping self-locking protection; only when the control signal is at low level and the maintenance current is withdrawn, the tripping self-locking protection can be canceled. Its characteristics are: the tripping protection action is fast, and it can be turned off at the microsecond level; the signal is optically isolated, the anti-interference ability is strong, and the reliability is high. In this circuit, the bidirectional thyristor output optocoupler model is MOC3083, and the triode output optocoupler model is 4N38.

Fig. 4 is a functional block diagram of the sampling circuit of the solid state power controller. The sampling circuit is composed of a sampling resistor RS connected in series in the output circuit and an amplifying circuit. In the figure, RL is a load. The sampling voltage signal of the sampling resistor RS is amplified by the amplifying circuit and then sent to the microcontroller circuit. Fig. 5 is an electrical schematic diagram of an embodiment of the amplifier circuit in the sampling circuit of the solid state power controller. The amplifying circuit in the sampling circuit is composed of an operational amplifier V11 and an amplifying circuit composed of resistors R10 and R11. The sampling signal URS of the sampling resistor is added to the input port 3 of the operational amplifier V11, and the input port 2 of the operational amplifier V11 is grounded through the resistor R10. The resistor R11 is connected between the input port 2 and the output port 6 of the operational amplifier V11, and the amplified sampling signal is sent from the output port 6 of the operational amplifier V11 to the input port 3 of the microcontroller V12. When the solid power controller is working normally, the load sampling signal URS millivolt voltage value is added to the input port 3 of the operational amplifier V11, and is amplified by the operational amplifier V11. The magnification factor is determined by the value of R11/R10, and the magnification factor R11/R10=10 times ; The amplified load sampling signal is added to the microcontroller V12 port 3 by the output port 6 of the operational amplifier V11, and the sampled analog voltage signal is converted into a digital signal by the A/D converter in the microcontroller V12. The compiled software program realizes the output of the load working status. In the circuit, the operational amplifier V1 model is OP193, and the microcontroller V2 model is PIC12F675.

When the solid power controller is overloaded or short-circuited, the overload or short-circuit current obtains the millivolt voltage value signal URS through the sampling circuit, which is amplified by the operational amplifier V11. The magnification factor is determined by the value of R11/R10, and the magnification factor R11/R10=10 times; The final overload or short-circuit sampling signal is output by the operational amplifier V11 output port 6, which outputs a voltage signal proportional to the overload or short-circuit current, which is added to the microcontroller V12 port 3, and the A/D converter in the microcontroller V12 will sample to The analog voltage signal is converted into a digital signal, and the judgment of different trip times under different overload or short-circuit currents is realized through a pre-programmed software program, and a trip protection pulse U2 is output to control the output of the solid power controller to achieve the purpose of shutting off the output. At the same time, a trip status signal U2out and a load switch status signal U3out are output.

Fig. 6 Structural diagram of the installation process of the sampling resistor of the solid power controller. The utility model adopts the current sampling method of series resistors in the output circuit. The signal obtained by the overload or short-circuit current through the sampling circuit is a millivolt value, which needs to be amplified by the signal amplification circuit to output a voltage signal proportional to the load current and sent to the micro. Controller PIC. It is characterized by high accuracy of current detection, within a certain temperature range, the resistance value changes very little, and the product consistency is good; when the current is small, the sampling of the load current is better with the resistance sampling method; but when the current is large, the power The power consumption is large, and the series sampling resistor produces a certain output voltage drop, which increases the voltage drop of the solid-state power controller, increases the power consumption of the solid-state power controller, and requires high heat dissipation. In the utility model, the sampling resistor RS is closely attached to the ceramic DBC board, (the ceramic sheet 2 and the copper clad 3 on it constitute the ceramic DBC board) so that the heat generated can quickly pass through the ceramic DBC board, the copper base plate 1 and the heat dissipation The path of the circuit breaker is scattered, and it is verified by experiments that the voltage consistency of the sampling signal is very good, which effectively avoids the influence of the heat increase of the sampling resistance.

Claims (5)

1. solid power controller, by microcontroller circuit, biasing circuit, buffer circuit, the tripping operation feedback circuit, the output feedback circuit, constant-current circuit, sample circuit and output are formed, biasing circuit, buffer circuit, the tripping operation feedback circuit, the output feedback circuit, constant-current circuit, sample circuit and output and microcontroller circuit join, it is characterized in that described output is by power field effect pipe, latching circuit reaches the drive circuit that is made of transistor drive circuit and quick discharging circuit and forms, the output of latching circuit connects drive circuit, and the output of drive circuit connects power field effect pipe.

2. solid power controller according to claim 1, it is characterized in that transistor drive circuit is by triode output type photoelectrical coupler (V1) in the described output, NPN triode (V4), positive-negative-positive triode (V2), voltage-stabiliser tube (V6, V8), resistance (R1-R4), resistance (R6, R7), electric capacity (C1) constitutes, described quick discharging circuit is by NPN triode (V3), positive-negative-positive triode (V5), resistance (R5) constitutes, the control voltage signal (U1) of microcontroller circuit is by the positive pole input of photoelectrical coupler (V1) luminous tube, the negative pole of luminous tube is by voltage-stabiliser tube (V8) ground connection, resistance (R1) is connected on the base stage that photoelectrical coupler (V1) is received light pipe, between the ground connection emitter-base bandgap grading, its collector electrode is by parallel resistor (R3), electric capacity (C1) connects the base stage of triode (V2), resistance (R2) is connected on the base stage of triode (V2), between emitter-base bandgap grading, the collector connecting transistor (V4 of triode (V2), V5) base stage, the collector electrode of triode (V3) also passes through resistance (R4) ground connection; Triode (V4, V5) common emitter, the collector electrode of triode (V5) is by resistance (R5) ground connection, resistance (R6, R7) series connection is between the grid of the emitter-base bandgap grading of triode (V4, V5) and power field effect pipe (V7), and voltage-stabiliser tube (V6) is connected between the contact and ground of resistance (R6, R7).

3. solid power controller according to claim 1 and 2; it is characterized in that described latching circuit is by bidirectional triode thyristor output type photoelectrical coupler (V10); triode output type photoelectrical coupler (V1); resistance (R1; R8); voltage-stabiliser tube (V8) is formed; the positive pole of bidirectional triode thyristor output type photoelectrical coupler (V10) luminous tube connects trip protection pulse signal (U2); minus earth; it receives an electrode grounding of light pipe bidirectional triode thyristor; the positive pole of another electrode and triode output type photoelectrical coupler (V1) luminous tube connects control signal (U1) by resistance (R8); the negative pole of triode output type photoelectrical coupler (V1) luminous tube is by voltage-stabiliser tube (V8) ground connection; resistance (R1) is connected on the base stage that triode output type photoelectrical coupler (V1) is received light pipe; between emitter-base bandgap grading, its collector electrode output drive signal of receiving light pipe is to drive circuit.

4. solid power controller according to claim 1 and 2, it is characterized in that described sample circuit is made up of sample resistance of connecting in the output loop (RS) and amplifying circuit, the sampling voltage signal of sample resistance (RS) is sent into microcontroller circuit after amplifying circuit amplifies.

5. solid power controller according to claim 4 is characterized in that described sample resistance (RS) is close on the ceramic DBC plate.

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