CN207283518U

CN207283518U - A kind of DC solid-state relay

Info

Publication number: CN207283518U
Application number: CN201721276479.7U
Authority: CN
Inventors: 尹向阳; 王保均; 陶小丽
Original assignee: Mornsun Guangzhou Science and Technology Ltd
Current assignee: Mornsun Guangzhou Science and Technology Ltd
Priority date: 2017-09-29
Filing date: 2017-09-29
Publication date: 2018-04-27
Anticipated expiration: 2027-09-29

Abstract

The utility model discloses a kind of solid-state relay, including direct current input positive terminal, direct current input negative terminal, direct current output plus end, direct current output negative terminal, control terminal plus end, control terminal negative terminal, isolation circuit, drive circuit, first switch, second switch, first diode and the second diode, as a result of biswitch and the mode of double fly-wheel diode interconnections, the energy stored using loading in end line cannot be mutated, new path is found for the flowing that continues of the electric current by fly-wheel diode, the path realizes the energy stored in load end line and is fed back into DC grid, it is achieved thereby that the recycle without damage of energy, and small product size is small, cost is low and can be suitably used for middle large-power occasions.

Description

A kind of DC solid-state relay

Technical field

It the utility model is related to solid-state relay, more particularly to DC solid-state relay.

Background technology

Existing solid-state relay schematic diagram is as shown in Figure 1, by control terminal plus end K+ and control terminal negative terminal K-, load Rectify terminal L+ and load end negative terminal L-, shell 1, internal isolation circuit 2, drive circuit 3 and switch S compositions.It is therein Isolation circuit 2 is used for realization isolating for low voltage control end and high-voltage load end, and drive circuit 3 is used for input low voltage control end The large current load at switch S driving loads end is supplied to after faint control signal amplification.

For existing solid-state relay when disconnecting, switch S both ends can produce very big peak voltage, for this reason, it may be necessary to S both ends parallel connections absorbing circuit 4 is switched, the solid-state relay schematic diagram of absorbing circuit 4, the suction have as been internally integrated shown in Fig. 2 Circuit 4 is received to be composed in series by resistance R and capacitance C.

The operation principle of absorbing circuit 4 shown in Fig. 2 is：During stable state, the electric current of load end is through switching S circulations；When failure occurs, Switch S to disconnect, the electric current of load end is shifted to RC branches, is charged to capacitance C by RC branches, due to the voltage at capacitance C both ends It can not be mutated, the voltage at switch S both ends slowly rises by 0, so as to inhibit the peak voltage at switch S both ends, reduces Impact of the short circuit current flow to switch S, protects other power electronic devices on circuit not to be damaged.

Foregoing circuit there are the problem of it is as follows：

(1) load the energy part stored in end line to be consumed by resistance R fevers, another part is stored by capacitance C Absorb, work as Failure elimination, switch S conductings, capacitance C will discharge, which is unfavorable for power train to damage absorption That unites is energy saving；

(2) when load the energy stored in end line it is larger when, it is desirable to the volume of RC is larger, and cost is higher, in Powerful solid-state relay does not apply to simultaneously.

As China's economy develops rapidly and the modernization progressively of industrial traffic department, direct current power load capacity are also held Continuous increase, with the increase of voltage class and rated current, cut-offfing for high-capacity direct current short circuit current flow becomes abnormal difficult, it is opened The requirement of disconnected time is also increasingly harsher, and DC solid-state relay becomes restricts high pressure, the bottle of high-capacity direct current electric power system Neck.

Such as new-energy automobile, using high voltage (400-1200V), middle high current (10-1000A) and powerful straight Solid-state relay is flowed, for electric automobile motor power on the market generally in 100Kw or so, max. speed is higher, electronic at present The power that machine needs is bigger；For another example solar photovoltaic power plant, DC bus-bar voltage are up to 800-1500V, lightning protection DC cabinet power Up to 30-500Kw；Straightening stream integrated power system in army's boat, ship, busbar voltage are up to more than 3000V, and power is very big, choosing Select whether motor is 450Kw using the conventional power separation of medium voltage electricity standard；Extra-high voltage long range DC transmission system, line Road voltage is up to ± 800kV, electric current is up to 10kA, and power is then up to 8000Mw.

Above-mentioned high pressure, high current occasion are required to apply powerful DC solid-state relay, and the prior art does not have body also The technical solution that product is small, cost is low and energy saving.

Utility model content

Have in view of that, the technical problem to be solved by the present invention is to provide a kind of DC solid-state relay, can realize body Product is small, cost is low, energy saving and be suitable for middle large-power occasions.

The technical solution that the utility model will solve above-mentioned technical problem is as follows：

A kind of DC solid-state relay, it is characterised in that：

Including at least six terminals, be respectively direct current input positive terminal, direct current input negative terminal, direct current output plus end, Direct current output negative terminal, control terminal plus end and control terminal negative terminal；

Further include：Isolation circuit, drive circuit, first switch, second switch, the first diode and the second diode；The One switch be connected to direct current input positive terminal son direct current output plus end between, second switch be connected to direct current input negative terminal son and Between direct current output negative terminal, the anode connection direct current output negative terminal of the first diode, the cathode connection of the first diode is directly Flow input positive terminal, anode connection direct current input negative terminal of the second diode, the cathode connection direct current output of the second diode Plus end, isolation circuit first input end connection control terminal plus end, the second input terminal of isolation circuit connection control terminal negative terminal, Isolation circuit output terminal connects drive circuit, and the first output terminal of drive circuit connects the control terminal of first switch, drive circuit the Two output terminals connect the control terminal of second switch；

Isolation circuit receives the control signal of control terminal plus end and the input of control terminal negative terminal, and isolates and be transmitted to driving Circuit；

Drive circuit receives the control signal that transmits of isolation circuit isolation, and first switch and the are supplied to after amplifying Two switches.

The first equivalent substitution as such scheme, it is characterised in that：By direct current input negative terminal therein altogether, from And reduce a terminal.

Second of equivalent substitution as such scheme, it is characterised in that：By control terminal plus end therein and control terminal Two terminals of negative terminal replace with accessory power supply power supply plus end, accessory power supply power supply three terminals of negative terminal and enabled terminal, So as to add a terminal；Isolation circuit has three input terminals at this time, and isolation circuit first input end connection accessory power supply supplies Electric plus end, the second input terminal of isolation circuit connection accessory power supply power supply negative terminal, the connection of the 3rd input terminal of isolation circuit are enabled Terminal.

The third equivalent substitution as such scheme, it is characterised in that：By direct current input negative terminal therein altogether, this Place reduces a terminal；Two terminals of control terminal plus end therein and control terminal negative terminal are replaced with into accessory power supply power supply Plus end, accessory power supply power supply negative terminal and enabled terminal, add a terminal, isolation circuit has three inputs at this time herein End, isolation circuit first input end connection accessory power supply power supply plus end, the second input terminal of isolation circuit connection accessory power supply supply Electric negative terminal, the enabled terminal of the 3rd input terminal of isolation circuit connection.

Equivalent substitution as the third above-mentioned equivalents, it is characterised in that：Accessory power supply is powered negative terminal Also altogether, so as to reduce a terminal.

The first improvement as such scheme, it is characterised in that：First diode and the second diode are multiple two poles Pipe is composed in series.

Second of improvement as such scheme, it is characterised in that：First switch both ends are parallel with by first resistor and The series circuit of one capacitance composition；Second switch both ends are parallel with the series circuit being made of second resistance and the second capacitance.

Equivalent substitution as above-mentioned second of improvement project, it is characterised in that：First switch both ends are parallel with the first electricity Hold, second switch both ends are parallel with the second capacitance.

Improved as above-mentioned second of improvement project and its further of equivalent substitution, it is characterised in that：First diode Anode and the first diode cathode between be parallel with the cathode of the 3rd capacitance, the anode of the second diode and the second diode Between be parallel with the 4th capacitance.

Improved again as above-mentioned second of improvement project and its further improved of equivalent substitution, it is characterised in that： Further include the thermistor of the first negative temperature coefficient and the thermistor of the second negative temperature coefficient, the temperature-sensitive of the first negative temperature coefficient The series circuit that resistance is made of in its both ends parallel connection first resistor and the first capacitance again after first connecting with first switch, second is negative What the thermistor of temperature coefficient was made of in its both ends parallel connection second resistance and the second capacitance again after first connecting with second switch Series circuit.

Equivalent substitution as the above-mentioned further improvement project of the third improvement project, it is characterised in that：Further include first The thermistor of the thermistor of negative temperature coefficient and the second negative temperature coefficient, the thermistor of the first negative temperature coefficient and first Switch first connect after again in its both ends first capacitance in parallel, after the thermistor of the second negative temperature coefficient is first connected with second switch Again in its both ends the second capacitance in parallel.

The 4th kind of improvement as such scheme, it is characterised in that：It is in parallel in the first diode and the second diode both ends Synchronous rectifier.

Preferably, isolation circuit uses photoelectric isolating circuit, coil, magnetoelectricity isolation circuit or piezoelectric ceramics isolation circuit.

Preferably, first switch and/or second switch can use the electronic switches such as metal-oxide-semiconductor, IGBT or silicon-controlled.

Preferably, the DC solid-state relay is packaged with shell.

As the embodiment of shell, it can be square or circular.

Preferably, six terminals are uniformly distributed in shell side face or bottom.

Preferably, it is also associated with control circuit between control terminal terminal and isolation circuit.

The more existing solid-state relay of the utility model damages absorption scheme and proposes a kind of brand-new technical concept：Using Biswitch and the mode of double fly-wheel diode interconnections, cannot be mutated using the energy that is stored in end line is loaded, by continuous Stream diode finds new path for the flowing that continues of the electric current, which realizes the energy stored in load end line and returned It is fed in DC grid, it is achieved thereby that the recycle without damage of energy.

The application has beneficial effect prominent as follows relative to the prior art：

(1) when first switch and second switch disconnect, the first diode and the second diode store to load in end line Energy flow provide free wheeling path so that the peak voltage very little produced in first switch and second switch so that first The voltage stress that switch and second switch needs are born is small；

(2) first diodes and the second diode are by DC input voitage clamper, it is necessary to which the voltage stress born is more existing Technology is small；

The free wheeling path that (3) first diodes and the second diode are formed realizes the energy quilt stored in load end line Feed back in DC grid, realize the energy stored in load end line when switching off by recycle without damage so that system It is more energy saving, especially DC solid-state relay frequent movement when energy-saving effect it is more obvious；

(4) circuit is extremely simple, implements to be very easy to, and small, of low cost, and big in voltage height, electric current The advantage of severe occasion the utility model will be apparent from；

(5) energy in transfer switch is further speeded up by capacitance so that the electric current in switch reduces, peak voltage subtracts It is small, further suppress du/dt and overvoltage so that the backward voltage of diode sum is unlikely to excessive and breakdown damage.

Brief description of the drawings

The existing solid-state relay schematic diagrams of Fig. 1；

The existing solid-state relays of Fig. 2 are internally integrated the schematic diagram of absorbing circuit；

Fig. 3 the utility model first embodiment schematic diagrams；

Fig. 4-1 is emulation voltage, the current waveform that switch ends during short trouble occur for Fig. 1 circuits；

Fig. 4-2 is emulation voltage, the current waveform that switch ends during short trouble occur for Fig. 2 circuits；

Fig. 4-3 is emulation voltage, the current waveform that switch ends during short trouble occur for Fig. 3 circuits；

Fig. 5 the utility model second embodiment schematic diagrams；

Fig. 6 the utility model 3rd embodiment schematic diagrams；

Fig. 7 the utility model fourth embodiment schematic diagrams.

Embodiment

It is with reference to the accompanying drawings and embodiments, further to the utility model in order to which the utility model is more clearly understood Describe in detail.It should be appreciated that specific embodiment described herein is not used to limit this only to explain the utility model Utility model.

First embodiment

Fig. 3 show the utility model first embodiment schematic diagram, which includes six terminals, is respectively that direct current is defeated Enter plus end Vin+, the sub- Vin- of direct current input negative terminal, direct current output plus end Vout+, direct current output negative terminal Vout-, control Rectify terminal K+ and control terminal negative terminal K-；Further include：Shell 1, isolation circuit 2, drive circuit 3, first switch S1, second open Close S2, the first diode D1 and the second diode D2；First switch S1 is connected to the sub- Vin+ of direct current input positive terminal and direct current output Between plus end Vout+, second switch S2 is connected between the sub- Vin- of direct current input negative terminal and direct current output negative terminal Vout-, The cathode connection direct current input positive terminal of anode connection direct current output the negative terminal Vout-, the first diode D1 of first diode D1 The cathode connection direct current of anode connection direct current the input negative terminal sub- Vin-, the second diode D2 of sub- Vin+, the second diode D2 are defeated Go out plus end Vout+, 2 first input end of isolation circuit connection control terminal plus end K+, the connection control of 2 second input terminal of isolation circuit Negative terminal K- in end processed, 2 output terminal of isolation circuit connection drive circuit 3,3 first output terminal of drive circuit connection first switch S1's Control terminal Ki1, the control terminal Ki2 of 3 second output terminal of drive circuit connection second switch S2.

Isolation circuit receives the control signal of control terminal plus end K+ and control terminal negative terminal K- inputs, and isolates and be transmitted to Drive circuit 3；Drive circuit 3 receives isolation circuit 2 and isolates the control signal transmitted, and is supplied to first switch after amplifying S1 and second switch S2；First switch S1 and second switch S2 is used to be switched on or switched off direct current output plus end Vout+ and direct current Export the electric current of negative terminal Vout- outputs.

Isolation circuit 2 can use photoelectric isolating circuit, coil, magnetoelectricity isolation circuit or piezoelectric ceramics isolation circuit etc.； Drive circuit 3 can use the circuit of relay composition or the bidirectional switch circuit of two field-effect tube reversal connection compositions；First opens The electronic switch such as metal-oxide-semiconductor, IGBT or silicon-controlled can be used by closing S1 and second switch S2, this for those skilled in the art and Speech is known technology, where not being the innovative point of the utility model, does not draw isolation circuit 2, drive circuit 3, the One switch S1 and the specific circuit diagrams of second switch S2.

When electric system works normally, switch S1 and switch S2 are closed, diode D1 and diode D2 because reverse-biased and End, the current direction in circuit is：The sub- Vin+ of direct current input positive terminal → switch S1 left ends → switch S1 right ends → direct current output Plus end Vout+ → load → direct current output negative terminal Vout- → switch S2 right ends → switch S2 left ends → direct current input negative terminal Sub- Vin-.

To illustrate the beneficial effect of the present embodiment, inventor has carried out simulation comparison analysis for Fig. 1, Fig. 2 and Fig. 3, imitates True parameter is：Inductive load, switch S1 and the S2 that the load that input voltage 1kV, load end are connect is 1H turn off moment electric current and are 100A, switch S1 and S2 shut-off resistance are 10M Ω, the switch S1 and S2 turn off process times are 3ms, resistance R resistance values are 1k Ω, electricity It is 1uF to hold C capacitances.

Fig. 4-1 to Fig. 4-3 is respectively emulation voltage, the current waveform that switch ends during short trouble occur for Fig. 1-3 circuits, Wherein V1 is that voltage waveform, the V2 at Fig. 1 switch S both ends are that voltage waveform, the V3 that Fig. 2 switchs S both ends are Fig. 3 switch S1 both ends Voltage waveform, I1 are that current waveform, the I2 in Fig. 1 switches S are that current waveform, the I3 that Fig. 2 switchs in S are in Fig. 3 switches S1 Current waveform.

It is analyzed as follows to what the voltage waveform V3 and current waveform I3 of the application Fig. 4-3 were carried out：

It was found from Fig. 4-3, for DC circuit occurs for 0ms the short trouble moment, is denoted as t0；0.9ms switchs S1 both end voltages Begin to ramp up, switching S1 for the present embodiment (i.e. Fig. 3) turns off the moment, is denoted as t1；It is defeated that 1.3ms switch S1 both end voltages rise to direct current Going out the voltage of plus end Vout+, the electric current switched in S1 is begun to decline, and is the present embodiment (i.e. Fig. 3) diode D2 start-up times, It is denoted as t2.

From the t1 moment, the voltage of direct current output plus end Vout+ starts to reduce, i.e., diode D2 cathode voltages start to drop Low, to the t2 moment, diode D2 cathode voltages are less than its anode voltage (i.e. the voltage of the sub- Vin- of direct current input negative terminal), diode D2 is turned on, diode D1 positively biaseds, and diode D1 conductings, form continuous current circuit：Diode D2 anodes → diode D2 cathodes → straight Flow the sub- Vout+ → load of output plus terminal → direct current output negative terminal Vout- → diode D1 anodes → diode D1 cathodes.Due to The sub- Vin+ of diode D1 cathodes connection direct current input positive terminal, the diode D2 anodes connection sub- Vin- of direct current input negative terminal, thus it is negative Carry the energy stored in end line and be fed back to DC grid, so as to fulfill the recycle without damage of energy so that electric system is more Supernumerary segment energy.

It should be noted that waveform V3 and I3 are directed to switch S1 and switch the situation that S2 is simultaneously switched off, for ability For the technical staff in domain, it is known technology that switch S1 is arranged to coordinated signals with switch S2.

Waveform and Fig. 3 contrasts when Fig. 1, Fig. 2 switch S are disconnected is as follows：

As can be known from the above table, peak voltage is up to 430KV when the switch S in Fig. 1 does not take absorption measure, is inputted for direct current 430 times of voltage, duration 2ms；After switch S in Fig. 2 takes RC to absorb spike, peak voltage also has 90KV, is straight Flow input voltage 90 times, duration is still 2ms；Fig. 3 using the present embodiment absorption scheme after, peak voltage be clamped for The time that DC input voitage Vin, switch S1 and S2 both ends electric current are reduced to needed for 0 is 1.7ms, which has also been reduced, because This, the present embodiment can realize goal of the invention.

It should be noted that existing diode highest pressure can reach several kilovolts, for higher voltage occasion, to divide The first diode D1 and the voltage stress at the second diode D2 both ends are carried on a shoulder pole, the first diode D1 and the second diode D2 can be designed To be made of multiple Diode series, it is noted that polarity is, it is necessary to which a positive negative connection, this is for those skilled in the art during series connection For known technology.

It was found from Fig. 4-3 waveforms, when short trouble occurs for DC circuit, after certain delay (t1-t0), switch S1 is just turned off, and at t1 to the t2 moment, since diode D2 is not turned on also at this time, the electric current in inductive load cannot be mutated, therefore Switch S1 in electric current remain unchanged, switch S1 in voltage sharply increase, cause switch S1 instantaneous powers it is very big, which is Similarly S2 instantaneous powers are also very big for symmetric circuit, are easily damaged switch S1 and switch S2, therefore, this utility model will produce Further improved technical solution, refers to second embodiment.

Second embodiment

Fig. 5 is the utility model second embodiment schematic diagram, is compared with Fig. 1 differences：Switch S1 both ends be parallel with by The series circuit of resistance R1 and capacitance C1 compositions, switch S2 both ends are parallel with the series circuit being made of resistance R2 and capacitance C2.

It should be noted that the position of resistance R1 and capacitance C1 can exchange, the position of resistance R2 and capacitance C2 can also Exchange, be equivalent after exchanging position for RC Tandem devices, this is common knowledge for a person skilled in the art.

In t1 to t2, switch the RC buffering branches that the electric current in S1 is formed by resistance R1 and capacitance C1 and shunted, Alleviate the burden of switch S1, it is suppressed that du/dt and overvoltage, after t2 moment diodes D2 is turned on, RC buffers the electricity of branch Stream is quickly transferred to the absorption circuit of diode D2 and D1 composition, so as to protect switch S1 not damaged by overvoltage, similarly opens S2 is closed also to be protected.

When DC input voitage is up to thousands of to up to ten thousand V, direct current input current is up to thousands of to up to ten thousand A, diode D1 Diode and D2 both ends will bear very high voltage stress and current stress, will be easily damaged diode D1 and diode D2, therefore the utility model will produce further improved technical solution, refer to 3rd embodiment.

It should be noted that removing the resistance R1 and R2 in two-way RC buffering branches, the present embodiment can be equally realized Goal of the invention, applicant remove resistance R1 and R2 by circuit simulation discovery, and the voltage that electric current declines process diminishes, peak voltage Reduce, implementation result is even even more ideal.

3rd embodiment

Fig. 6 is the utility model 3rd embodiment schematic diagram, is compared with Fig. 5 differences：The both ends of diode D1 are in parallel There is capacitance C3, the both ends of diode D2 are parallel with capacitance C4.

In t1 to t2, charging current can be formed in capacitance C3 and capacitance C4, accelerates to absorb the electric current in switch S1 and S2, So that the electric current in switch S1 and S2 reduces, peak voltage reduces, du/dt and overvoltage further suppress so that diode The backward voltage of D1 and D2 is unlikely to excessive and breakdown damage；When t2 moment diode D2 and D1 turn on to form absorption circuit Afterwards, capacitance C3 and capacitance C4 start to discharge.

The present embodiment during switch conduction there are it is certain the problem of：Switch S1 from disconnection become conducting when, capacitance C4 is directly just being charged by switching S1 with direct current input with the negative connection of direct current input, and capacitance C1 is discharged by switching S1, by It is smaller in switch S1 conducting resistances, therefore very big dash current can be produced, there is the risk of damage in switch S1, since circuit is Symmetrically, S2 is switched there is also same damage risk, therefore the utility model will produce further improved technical side Case, refers to fourth embodiment.

Fourth embodiment

Fig. 7 is the utility model fourth embodiment schematic diagram, is compared with Fig. 6 differences：Switch right end and two poles of S1 The thermistor NTC1 of negative temperature coefficient is in series between the cathode of pipe D2, is switched between the right end of S2 and the anode of diode D1 It is in series with the thermistor NTC2 of negative temperature coefficient.

It should be noted that the position of switch S1 and thermistor NTC1 can exchange, i.e. resistance R1 is inputted just with direct current The thermistor NTC1 of negative temperature coefficient is in series between the tie point of Vin+ and the left end for switching S1；Similarly, switch S2 and The position of thermistor NTC2 can also exchange, i.e. the tie point of the negative Vin- of resistance R2 and direct current input and the left end of switch S2 it Between be in series with the thermistor NTC2 of negative temperature coefficient, be equivalent after exchanging position for Tandem devices, this is for this area Technical staff for be common knowledge.

When switch S1 becomes conducting from disconnection, since thermistor NTC1 temperature is relatively low, resistance is larger, limits capacitance The charging current of C4 and the discharge current of capacitance C1, limit the size of dash current, protect switch S1, normal work Afterwards, since thermistor NTC1 generates heat, resistance declines, and does not influence the normal work of load, similarly switchs S2 and is also obtained protection.

It should be noted that for those skilled in the art, above-described embodiment is at least six ends Son, can also make following equivalent substitution：

(1) five terminals are included at least, by the sub- Vin- of direct current input negative terminal therein altogether so as to reduce a terminal；

(2) seven terminals are included at least, two terminals of control terminal plus end K+ therein and control terminal negative terminal K- are replaced It is changed to three accessory power supply power supply plus end, accessory power supply power supply negative terminal and enabled terminal (also referred to as control terminal) terminals； Isolation circuit has three input terminals at this time, isolation circuit first input end connection accessory power supply power supply plus end, isolation circuit the Two input terminals connection accessory power supply power supply negative terminal, the enabled terminal of the 3rd input terminal of isolation circuit connection；

(3) six terminals are included at least, reduce an end herein by the sub- Vin- of direct current input negative terminal therein altogether Son；Two terminals of control terminal plus end K+ therein and control terminal negative terminal K- are replaced with into accessory power supply power supply plus end, auxiliary Help three terminals of power supply power supply negative terminal and enabled terminal (also referred to as control terminal), add a terminal herein, this after There are three input terminals, isolation circuit first input end connection accessory power supply power supply plus end from circuit, isolation circuit second inputs End connection accessory power supply power supply negative terminal, the enabled terminal of the 3rd input terminal of isolation circuit connection；

(4) five terminals are included at least, by the accessory power supply power supply negative terminal in above-mentioned equivalent substitution (3) also altogether, from And reduce a terminal.

It the above is only the preferred embodiment of the utility model, it is noted that above-mentioned preferred embodiment should not regard For the limitation to the utility model, the scope of protection of the utility model should be subject to claim limited range.For For those skilled in the art, without departing from the spirit and scope of the utility model, it can also make some Shell 1, is such as designed as square or circular by improvements and modifications, terminal is uniformly distributed in shell side or bottom, in the one or two pole Pipe D1 and the second diode D2 both ends shunt-wound synchronous rectification tubes solve the problems, such as that diode drop is big and bear that electric current is small, is controlling Control circuit etc. is also associated between end terminal and isolation circuit, these improvements and modifications also should be regarded as the protection of the utility model Scope.

Claims

A kind of 1. DC solid-state relay, it is characterised in that：

It is respectively direct current input positive terminal, direct current input negative terminal, direct current output plus end, direct current including at least six terminals Export negative terminal, control terminal plus end and control terminal negative terminal；

Further include：Isolation circuit, drive circuit, first switch, second switch, the first diode and the second diode；First opens Connection is connected between direct current input positive terminal and direct current output plus end, and second switch is connected to direct current input negative terminal and direct current Between exporting negative terminal, the anode of the first diode connects direct current output negative terminal, and the cathode connection direct current of the first diode is defeated Enter plus end, anode connection direct current input negative terminal of the second diode, the cathode connection direct current output anode of the second diode Son, isolation circuit first input end connection control terminal plus end, the second input terminal of isolation circuit connection control terminal negative terminal, isolation Circuit output end connects drive circuit, and the first output terminal of drive circuit connects the control terminal of first switch, and drive circuit second is defeated Outlet connects the control terminal of second switch；

Isolation circuit receives the control signal of control terminal plus end and the input of control terminal negative terminal, and isolates and be transmitted to driving electricity Road；

Drive circuit receives the control signal that isolation circuit isolation transmits, and is supplied to first switch and second to open after amplifying Close.
2. DC solid-state relay according to claim 1, it is characterised in that：By direct current input negative terminal therein altogether Ground, so as to reduce a terminal.
3. DC solid-state relay according to claim 1, it is characterised in that：By control terminal plus end therein and control End two terminals of negative terminal replace with three accessory power supply power supply plus end, accessory power supply power supply negative terminal and enabled terminal ends Son, so as to add a terminal；Isolation circuit has three input terminals, isolation circuit first input end connection accessory power supply at this time Power supply plus end, the second input terminal of isolation circuit connection accessory power supply power supply negative terminal, the connection of the 3rd input terminal of isolation circuit make Can terminal.
4. DC solid-state relay according to claim 1, it is characterised in that：By direct current input negative terminal therein altogether Ground, reduces a terminal herein；Two terminals of control terminal plus end therein and control terminal negative terminal are replaced with into auxiliary electricity Source power supply plus end, accessory power supply power supply negative terminal and enabled terminal, add a terminal, isolation circuit has three at this time herein A input terminal, isolation circuit first input end connection accessory power supply power supply plus end, the second input terminal of isolation circuit connection auxiliary Power supply power supply negative terminal, the enabled terminal of the 3rd input terminal of isolation circuit connection.
5. DC solid-state relay according to claim 4, it is characterised in that：By accessory power supply power supply negative terminal also altogether Ground, so as to reduce a terminal.
6. DC solid-state relay according to claim 1, it is characterised in that：First diode and the second diode are more A Diode series composition.
7. DC solid-state relay according to claim 1, it is characterised in that：First switch both ends are parallel with by the first electricity Resistance and the series circuit of the first capacitance composition；Second switch both ends are parallel with the series electrical being made of second resistance and the second capacitance Road.
8. DC solid-state relay according to claim 1, it is characterised in that：First switch both ends are parallel with the first electricity Hold, second switch both ends are parallel with the second capacitance.
9. the DC solid-state relay according to claim 7 or 8, it is characterised in that：The anode of first diode and first The 3rd capacitance is parallel between the cathode of diode, is parallel between the anode of the second diode and the cathode of the second diode Four capacitances.
10. DC solid-state relay according to claim 9, it is characterised in that：Further include the heat of the first negative temperature coefficient The thermistor of quick resistance and the second negative temperature coefficient, the thermistor of the first negative temperature coefficient first connect with first switch after again In the series circuit that its both ends parallel connection is made of first resistor and the first capacitance, the thermistor of the second negative temperature coefficient and second The series circuit that switch is made of in its both ends parallel connection second resistance and the second capacitance again after first connecting.
11. DC solid-state relay according to claim 9, it is characterised in that：Further include the heat of the first negative temperature coefficient The thermistor of quick resistance and the second negative temperature coefficient, the thermistor of the first negative temperature coefficient first connect with first switch after again In its both ends first capacitance in parallel, the thermistor of the second negative temperature coefficient first connect with second switch after again in the parallel connection of its both ends Second capacitance.
12. DC solid-state relay according to claim 1, it is characterised in that：In the first diode and the second diode Both ends shunt-wound synchronous rectification tubes.
13. DC solid-state relay according to claim 1, it is characterised in that：Isolation circuit using photoelectric isolating circuit, Coil, magnetoelectricity isolation circuit or piezoelectric ceramics isolation circuit.
14. DC solid-state relay according to claim 1, it is characterised in that：Drive circuit is using relay composition The bidirectional switch circuit of circuit or two field-effect tube reversal connection compositions.
15. DC solid-state relay according to claim 1, it is characterised in that：First switch and/or second switch use The electronic switches such as metal-oxide-semiconductor, IGBT or silicon-controlled.
16. DC solid-state relay according to claim 1, it is characterised in that：DC solid-state relay is packaged with shell.
17. DC solid-state relay according to claim 16, it is characterised in that：Shell is square or circular.
18. DC solid-state relay according to claim 16, it is characterised in that：Six terminals are in shell side face or bottom It is uniformly distributed.
19. DC solid-state relay according to any one of claims 1 to 5, it is characterised in that：Control terminal terminal with every From being also associated with control circuit between circuit.