CN110062987A - Protection system - Google Patents

Abstract

Protection system (1) for electrolytic capacitor (109) comprising the current divider (2) that can be inserted between electrolytic capacitor (109) and reference potential；Current divider (2) includes the first branch and the second branch, and the first branch includes the controllable switch (3) with resistor R1, such as MOSFET, and to disconnect the first branch, the second branch includes the resistor R2 more much bigger than R1；Protection system includes comparator stage (4); it is used to control controllable switch (3) compared between threshold value T1 based on the signal S1 directly proportional with the voltage on current divider (2), and the amplifier stage (7) with gain for sending signal S1 to comparator stage (4)；Amplifier stage (7) includes the circuit (10) for controlling the gain of the amplifier stage (7) by comparator stage control, and to change gain between the first value A1 and second value A2, the first value A1 is greater than second value A2.

Description

Protection system

Technical field

It is especially a kind of for being designed as the mistake of protective condenser in automotive field the present invention relates to a kind of protection system Current protection system.

Background technique

Electronic control unit develops fabulous in the automotive industry, and the electricity that needs especially to filter is as input and anti- Come over to generate oscillation, the even oscillation of tens kHz magnitudes, this may interfere with its electric power network connected.

The reference implementation example of this specification is with electronically controlled electric fan comprising for driving corresponding radiator The dc motor of cooling fan, or even brushless motor, hereinafter quote it.

Brushless motor includes electronic card or controlling electronic devices inside it, monitors the operation of electric fan, and by The battery of vehicle is brushless motor power supply by direct current.

Electronic card include suitable control, for providing the power supply driver of machine winding, such as inverter, and be used for Filter the filter system of any oscillation of the supply voltage from route.

As described above, being also required in involved field with stringenter mode protection power source route from for example by driving The influence for the voltage ripple that dynamic device generates.

In order to meet the requirement of Electro Magnetic Compatibility, using the filter including electrolytic capacitor, be inserted into motor and Between route itself, to be sent to ground for any parasitic signal.

Therefore, these capacitors are not by the protection of the electronic equipment of motor, and are located at the input terminal of motor, by The influence of all transitions from motor power route.

From the perspective of controlling any overcurrent or violent transition, electrolytic capacitor is precise part, but due to filtering High capacity is needed, so it cannot be replaced with other component.

Therefore, there are above-mentioned incident, capacitor may be damaged or even explode, and electromagnetism Compliance is still unmet.

Summary of the invention

In this context, the main object of the present invention is to propose a kind of protection system, is designated specifically to protection electricity Container overcomes disadvantages mentioned above.

The first purpose of this invention is to provide a kind of protection system, in the incident that there is such as overcurrent In the case of keep filter condenser integrality.

Second object of the present invention be provide a kind of protection system, while even if capacitor potentially harmful event It is also able to maintain the reliability and efficiency of filter condenser later.

Third object of the present invention is to provide a kind of simple and relatively inexpensive protection system.

Fourth object of the present invention is the more reliable filter system of the solution that provides Yi Zhong than in the prior art System.

5th purpose of this specification is to provide a kind of reliable in terms of electromagnetic compatibility and satisfactory motor.

These purposes pass through the protection system for filtering system with feature described in claim 1,10,11 completely And/or filtering system and/or motor and/or the combination by one or more claims in the application appended claims To realize.

Above-mentioned first purpose according to the present invention, this specification are related to a kind of protection system for electrolytic capacitor.

The system includes between insertion electrolytic capacitor and reference potential (usually common potential or zero) to be protected Controllable switch, so that capacitor is no longer influenced by the influence of dangerous transient event after switch disconnects.

Advantageously, according to an aspect of the present invention, protection system is configured as closure switch at the end of transition, restores The operation of electrolytic capacitor.

In one embodiment, protection system includes current divider, is inserted between electrolytic capacitor and reference potential.

Current divider includes the first branch and second resistance branch wherein with controllable switch.

Controllable switch is, for example, MOSFET, the relative resistance device R1 with a few m Ω, and resistive branches include obtain bigger than R1 More, for example, about 100 Ω resistor R2.

Advantageously, as will be described in more detail, resistor R2 mean even if when MOSFET disconnect when, in current divider Terminal at voltage also can always measure.

Moreover, because resistor R2 is more much bigger than the equivalent series resistance R of electrolytic capacitor, so when MOSFET is disconnected When, bear most of voltage.

Protection system includes comparator stage, which disconnects for controlling controllable switch and closure switch, with protection Or restore electrolytic capacitor.

In one embodiment, comparator stage have for example by divider obtain for the first defeated of reference threshold T1 Enter, and the second input of the signal S1 for being compared with threshold value T1.

Comparator stage has output G, and for being cut between corresponding closed configuration and corresponding open configuration The controllable switch changed is connected to.

In the case where controllable switch is the preferable case of MOSFET, the output of comparator stage is connected to the grid of transistor.

For the signal S1 being compared with threshold value T1 from the amplifier stage with gain, which also constitutes protection system A part of system.

According to one embodiment, the output that there is amplifier stage the second input with comparator stage to be connected to is used for signal S1 is sent to the second input of comparator stage.

Amplifier stage has the first input being connected to output, that is to say, that upper reversed in the first input of amplifier stage Driving output.

Amplifier stage includes the second input, is parallel-connected to current divider, the voltage at terminal to receive controllable switch As input.

According to an aspect of the present invention, amplifier stage has as the voltage at the terminal of the current divider of input signal, That is, if the intrinsic resistance R1 of R2 ratio MOSFET is much bigger, voltage when MOSFET closure at its terminal, and work as MOSFET Voltage when disconnection, at the terminal of current R2.

Amplifier stage includes the circuit for controlling its gain.

Control circuit is controlled by comparator stage, for changing the increasing of amplifier stage between the first value A1 and second value A2 Benefit, the first value A1 are greater than second value A2.

In one embodiment, control circuit configures in this way: the gain of amplifier stage is when in current divider There is the first value A1 when MOSFET is closed, and there is second value A2 when MOSFET is disconnected.

In this way, comparator stage receives signal S1 as input, and signal S1 begins when MOSFET is disconnected The transition on electrolytic capacitor is indicated eventually.

In this way, the transition that system keeps monitoring that MOSFET is caused to disconnect.

In one embodiment, the first yield value A1 is substantially equal to four times of the second yield value A2 in terms of the order of magnitude.

In one embodiment, the second yield value A2 is substantially single times.

According to an aspect of the present invention, amplifier stage includes the operational amplifier installed in a manner of noninverting.

Amplifier includes the output of amplifier stage, the first input and the second input.

Noninverting component make operational amplifier have by the resistor R3 and resistor R4 of shown installation acquisition the One yield value A1.

First gain A 1 is defined as A1=1+R4/R3 by resistor R3 and R4.In a preferred embodiment, resistor R4 is electricity Three times for hindering device R3, that is, R4=3R3, so that the gain of amplifier is about 4.

In order to make the second gain A 2 be single times or substantially single times, amplifier stage includes being inserted in 3rd resistor device R3 The second controllable switch between reference potential, such as MOSFET.

MOSFET has and the output G of comparator stage respective gates be connected to and is controlled by it, as MOSFET be electrolysed Capacitor is substantially connected.

The 2nd MOSFET can be controlled between closed configuration and open configuration, wherein in the closed configuration, in reference electricity Closed electrical resistor R3 on position.

Closed configuration corresponds to the first yield value A1 of amplifier stage, and second that open configuration corresponds to amplifier stage increases Beneficial value A2.

In view of the high impedance of anti-phase input, yield value A2 is substantially single times, so that operational amplifier is actually Voltage-tracing device, that is to say, that the voltage-tracing device of the voltage especially at the terminal of R2.

When voltage is lower than above-mentioned threshold value T1, comparator stage is closed two MOSFET, and protection system returns to electrolytic capacitor The initial configuration that device operates in its filter function.

In one embodiment, protection system according to the present invention includes the second input in current divider and amplifier stage Between voltage stabilization grade.

According to the second aspect of the invention, the present invention relates to a kind of filter systems comprising first party according to the present invention The protection system and electrolytic capacitor in face.

According to the third aspect, the present invention relates to a kind of motors comprising rotor, stator, for accommodate the shell of stator with And the electronic control card of the operation for monitoring motor, wherein motor includes filter system according to the third aspect of the invention we System.

In one embodiment, electronic card includes filter system.

It in one embodiment, will be in the electronic card insertion shell with filter system.

Protection system prevents damage electrolytic filter capacitor in the transient event for carrying out automatic network, and will at the end of transition It restores.For these reasons, in the case that protection system may close electrolytic capacitor inside motor, outside is not needed yet Intervene and avoid the risk of capacitor explosion.

In one embodiment, motor according to the third aspect of the invention we includes outer to form sealing for closing shell The lid of shell, and filter system is inserted into sealing shell.

According to an aspect of the present invention, filtering system uses the filter inductance pair being typically found in motor control card The power supply of motor input is filtered.

Electrolytic capacitor is preferably connected to the power circuit between inductance and the power supply of motor.

In one embodiment, filter system is mounted in the box outside motor along opposed power route.

Detailed description of the invention

As shown in the picture, of the invention in preferred but nonexcludability embodiment the non restrictive description of protection system Other feature and advantage become apparent, in which:

- Fig. 1 shows the block diagram of the first embodiment using protection system according to the present invention；

Fig. 2 shows the block diagrams of the second embodiment of application protection system according to the present invention；

- Fig. 3 shows the partial circuit diagram of the box of the application specific details of aforementioned figures.

Specific embodiment

With reference to Fig. 1, number 100 indicates the motor of the one aspect according to this specification.

Motor 100 is substantially known type, and is only described and says in the required range of the understanding present invention It is bright.

In brief, motor 100 includes rotor, stator, the shell for accommodating stator and for monitoring motor 100 The electronic control card 101 of operation.

In present invention preferred embodiment of interest, motor 100 is the brushless motor with p-m rotor, hereinafter It will not be limited the scope of the invention with reference to the motor.

Motor 100 includes for preferably closing shell in a sealing manner to form the lid of closure 102.

As indicated, card 101 to be inserted into shell 102 and is closed.

Electronic card includes of a substantially known type and power supply not depicted driver 103, and for for its power supply Grade 104, be configured to it is to the input of driver 103, be filtered from the electricity of power circuit 105.

Substantially known grade 104 is particularly simple said including capacity cell 106 comprising the power supply with driver 103 At least one filter condenser of parallel connection insertion, and it is inserted in the inductance element 107 of positive power line road.

According to an aspect of the present invention, motor 100 includes another filter stage or system, is schematically illustrated as Block 108 is inserted between grade 104 and route 105, to filter out that the operation by motor 100 generates towards any of power circuit 105 It interferes (EMI electromagnetic interference), to meet the EMC Requirements usually required that.

Filter system 108 will be described below in detail, including electrolytic capacitor, schematically be shown by block 109 Out.

Filter system 108 further includes system for protective condenser 109, associated with it and with 1 label of number.

1 protective condenser 109 of system is from any transition from the route 105 powered for motor 100, to keep its complete Whole property and functionality.

In one embodiment, card 101 includes filter system 108.

With reference to Fig. 2, in the shown embodiment, EMI filtering stage 108 is located at motor between power circuit 105 and motor 100 Outside 100.

In this case, the power supply line under+5 volts for protecting system 1 is by motor 100, such as by relevant drive Dynamic device 103 picks up.

System 108 is for example inserted into its container 111, container 111 may be mounted near motor 100.

In automotive vehicles applications, for example, having if motor 100 is the motor of the fan for driving radiator cooling There is the container 111 of filtering system that can be located at vehicle in the compartment near motor 100.

Fig. 3 is illustrated in greater detail, more specifically, to the protection system 1 of the EMI electrolytic capacitor 109 being filtered One embodiment.

In fact, the current potential indicated in Fig. 1 and Fig. 2 with negative sign is expressed as reference potential or common potential or zero in Fig. 3.

In addition, schematically showing electrolytic capacitor by the equivalent network including capacitor C, resistance R and inductance L 109。

System 1 includes the current divider 2 being inserted between electrolytic capacitor 109 and reference potential.

Current divider 2 includes the first branch, and the first branch includes the controllable switch 3 with relative resistance device R1, such as MOSFET type electronic switch, clearly quotes it rather than is limited the scope of the present invention.

Current divider 2 includes the second branch, and the second branch includes resistor, and value R2 ratio R1 is much bigger.

If such as the magnitude of the resistor R1 of MOSFET 3 is m Ω, the value of resistor R2 is for example equal to 100 Ω.

It should be noted that in this way, the equivalent resistance R of resistor R1 also specific capacitance device 109 is much higher.

First branch can be disconnected by switch 3, and switch 3 can be controlled by its grid.

Protection system 1 includes comparator stage 4 or simple comparator, is used for control switch 3.

Comparator stage includes such as operational amplifier OP1, and has the first non-inverting input 5 for reference threshold T1, The second anti-phase input 6 of voltage signal S1 for being compared with threshold value T1, and in closed configuration and break with for control Open the output G of the grid connection of the switch 3 switched between configuration.

As described below, the threshold value T1 of comparator 4 corresponds to the max-thresholds electric current allowed on MOSFET3, that is, in capacitor Maximum acceptable electric current on device 109.

As shown, power under predetermined voltage for grade 4, such as+5 volts, under the preferable case of embodiment, Ke Yicong The card 101 of motor 100 is picked up.

Threshold value T1 is defined by divider using resistor RT1 and RT2, and the value of resistor RT1 and RT2 are for example respectively 1.55k Ω and 47k Ω.

Comparator stage 4 is configured as being changed to disconnect from closed configuration by switch 3 when the value of signal S1 is greater than threshold value T1 matching It sets, and when the value of signal S1 becomes smaller than threshold value T1, switch 3 is changed to closed configuration from open configuration.

Protection system 1 includes the amplifier stage 7 with gain, to provide signal S1 to comparator stage 4.

In one embodiment, grade 7 includes operational amplifier OP2 comprising output corresponding with the output of grade 7 and input OP2_out, the first anti-phase input 8 and the second non-inverting input 9.

As indicated, operational amplifier OP2 is installed in a manner of noninverting, and has and to be limited by resistor R3 and resistor R4 Yield value A1.

The yield value A1 of operation OP2 in noninverting component is provided by A1=1+R4/R3.

In one embodiment, three times, i.e. R4=3R3 of value of the value of resistor R4 equal to resistor R3, such as R3= 10k Ω, R4=30k Ω.

As indicated, input 8 is connected to output OP2_out, input 9 is in parallel with current divider 2, so that operation OP2 is received controllably Voltage at the terminal of switch 3 and at the terminal of resistor R2 is as input.

It should be noted that the feature of operational amplifier is in the present invention also in the connection description of the circuit of reference Fig. 3 It is considered known, especially includes very high input resistance, it is assumed that its value in the ideal case is infinitely great；It is very small Output resistance, it is also assumed that it is zero in the ideal case；And the approximation as caused by them.

Output OP2_out is connected to the second input 6 of comparator stage 4, for sending signal S1 to input 6.

Amplifier stage 7 includes the circuit 10 for controlling the gain controlled by comparator stage 4, in value A1 and second value Change the gain of grade 7 between A2, intermediate value A1 corresponds to the above-mentioned noninverting component with resistor R3 and R4, and the first value A1 is big In second value A2.

In one embodiment, the first yield value A1 is substantially equal to four times of the second yield value A2.

Second yield value A2 is substantially single times, because will be apparent with the continuation of the description, grade 7 can become For voltage-tracing device.

As shown in figure 3, amplifier stage 7 includes the second controllable switch 11 being inserted between resistor R3 and reference potential, example Such as MOSFET type electronic switch.

The output G of comparator stage is connected to switch 11, for being controlled it between closed configuration and open configuration, Wherein, closed configuration corresponds to the first yield value A1 of amplifier stage, and resistor R3 is connected to reference potential, and open configuration is corresponding In the second yield value A2 of amplifier stage.

In this configuration, as noted previously, as the impedance of the input of operation OP2 is substantially infinity, so gain Value A2 is equal to 1.

Comparator stage 4 is configured as being changed to switch 11 from closed configuration when the value of signal S1 becomes larger than threshold value T1 Open configuration, and when the value of signal S1 becomes smaller than threshold value T1, switch 11 is changed to closed configuration from open configuration.

In the embodiment shown in for example, protection system includes between current divider 2 and the input 9 of amplifier stage 7 Voltage stabilization grade 12.

With reference to the figure of Fig. 3, it should be noted that for the integrality of description, in an illustrated embodiment, protect system 1 Including the RC filter in the input of comparator stage.

In an illustrated embodiment, protection system 1 includes the output G and MOSFET 3 and MOSFET 11 positioned at comparator 4 Grid between resistor R5.

In use, under typical operating conditions, capacitor 109 with its operation between power supply and common potential and Filter out the electromagnetic interference generated by motor 100.

At typical condition, capacitor 109 actually sees MOSFET 3 at its own between common potential, MOSFET3 shows as short circuit in the very small situation of known resistance.

Since input signal S1 remains less than threshold value T1 and exports G as height, MOSFET 3 is kept by comparator 4 Closure.

Particularly, signal S1 is generated by grade 7, and grade 7 is in the case of the embodiment with yield value A1 amplifying MOSFET 3 Voltage at terminal.

Voltage at the terminal of MOSFET 3 is proportional to the electric current on MOSFET, that is to say, that its on capacitor 109 Electric current it is proportional, therefore signal S1 indicate capacitor 109 on electric current.

The yield value of grade 7 is A1, because MOSFET 11 is since it is always by the output G of the comparator stage 4 in high level It controls and is also closure.

Assuming that the value of the electric current usually recycled in MOSFET 3 under operating condition is very low, voltage will amplify in grade 7, It makes it possible to and is compared in grade 4 with predetermined threshold T1.

The threshold value T1 of comparator 4 is as described above according on the max-thresholds electric current allowed on MOSFET 3 i.e. capacitor 109 Maximum acceptable electric current.

Although the electric current on MOSFET 3, and the electric current on capacitor 109 is more than maximum permissible value in turn, from Comparison between S1 and T1 can explain that output G keeps high level, and MOSFET 3 and 11 is remained closed.

It can be incited somebody to action by the electric current on capacitor 109 and in turn in the violent transition usually from power circuit 105 In the case that electric current on MOSFET 3 is increased to value corresponding with maximum permissible voltage or more, output G becomes low level, MOSFET 3 and MOSFET 11 are switched to open configuration.

Substantially, once signal S1 that is proportional to the voltage at the terminal of MOSFET 3 and amplifying in grade 7 is more than Threshold value T1, output G will be reduced, and MOSFET 3 and MOSFET 11 just will disconnect.

In this configuration, in the case where MOSFET 3 and MOSFET 11 are disconnected, capacitor 109 is towards reference potential Series connection, resistor R2 have to be larger than the equivalent series resistance R of capacitor 109, bear the most of voltage for being applied to capacitor 109 Protected from transient influence.

In this configuration, amplifier stage 7 sees the relatively high voltage at the terminal of R2, and shows that triggering is disconnected Open the transition trend of MOSFET 3 and MOSFET 11.

Since MOSFET 11 is to disconnect, so grade 7 goes to gain A 2, when input of the resistor R4 relative to operation OP2 When impedance can be neglected, gain A 2 is substantially single times.

Therefore, signal S1 is proportional to the voltage at terminal R2, and the voltage is again proportional to the electric current on capacitor 109.

Therefore, in the step process, comparator 4 continue by the signal S1 proportional to the electric current on capacitor 109 with Threshold value T1 is compared, even if signal S1 is no longer amplified.

S1 follows the triggered transition trend for disconnecting MOSFET 3 and MOSFET 11, when it is lower than threshold value T1, compares The output G of device 4 is got higher again, is closed MOSFET 3 and MOSFET 11 again and is restored normal running conditions.

In other words, only when the output G of comparator 4 is got higher again and the grid of MOSFET 3 and MOSFET 11 are real Become+5V on border, when being closed corresponding switch, filtering system 108 just returns to normal operating condition.

Above-mentioned protection system may be implemented to protect any filtering electrolysis electricity for due to Electro Magnetic Compatibility and being inserted into motor upstream Influence of the container from the transition from power circuit.In transient process, protection of the capacitor by very big resistance should Resistance bears most of voltage for being applied, once but transition complete, since provided electronic switch is closed, system will Back to normal operating condition.

Claims (14)

1. one kind is used for the protection system of electrolytic capacitor (109), the system comprises:

Current divider (2) is inserted between electrolytic capacitor (109) and reference potential, and including the first branch and second point Branch, the first branch includes the controllable switch (3) with resistor R1, such as MOSFET, the second branch include more much bigger than R1 Resistor R2, the first branch can be disconnected by controllable switch (3), and the protection system includes

For controlling the comparator stage (4) of controllable switch (3), comparator stage (4) has the first input for reference threshold T1 (5), second of the signal S1 for being compared with threshold value T1 inputs (6) and between closed configuration and open configuration The output G being connected to controllable switch (3) of controllable switch (3) is controlled, the protection system includes

Amplifier stage (7) with gain, has

The output OP2_out being connected to the second input (6) of comparator stage (4) is sent out for the second input (6) to comparator stage The number of delivering letters S1,

The first input (8) being connected to opposite output OP2_out,

Second in parallel with current divider (2) inputs (9), and the voltage at the terminal for receiving current divider (2) is described as input Amplifier stage (7) include circuit (10) or control by gain that comparator stage controls to change between the first value A1 and second value A2 Variable-gain, the first value A1 are greater than second value A2.

2. protection system according to claim 1, wherein the first yield value A1 is substantially equal to the four of the second yield value A2 Times.

3. protection system according to any one of the preceding claims, wherein the second yield value A2 is substantially single times.

4. protection system according to any one of the preceding claims, wherein amplifier stage (7) includes operational amplifier OP2, the operational amplifier OP2 include the output OP2_out of amplifier stage (7), the first input (8) and the second input (9), fortune It calculates amplifier OP2 to install in a manner of noninverting, there is the first yield value A1, amplifier stage (7) includes 3rd resistor device R3 and the Four resistor R4, the first yield value A1 of formation are A1=1+R4/R3.

5. protection system according to claim 4, wherein R4 is three times of R3, that is, R4=3R3.

6. protection system according to claim 4 or 5, wherein amplifier stage (7) includes being inserted in 3rd resistor device R3 and ginseng The controllable switch (11) between current potential, such as MOSFET are examined, the output G of comparator stage (4) is connected to the second controllable switch (11), The output G of comparator stage (4) is used to control the second controllable switch (11) between closed configuration and open configuration, wherein amplifier First yield value A1 of grade (7) is corresponding with closed configuration, and the second yield value A2 of amplifier stage (7) is corresponding with open configuration, the Two yield value A2 are substantially single times.

7. protection system according to any one of the preceding claims comprising grade (12), the grade (12) are divided for stablizing Flow the voltage between device (2) and the second input (9) of amplifier stage (7).

8. protection system according to any one of the preceding claims, wherein comparator stage (4) is configured as signal S1 Value be greater than threshold value T1 when, by the first controllable switch (3) from closed configuration change to open configuration, and

When the value of signal S1 is less than threshold value T1, the first controllable switch (3) is changed from open configuration to closed configuration.

9. protection system according to claim 6, wherein comparator stage (4) is configured as being greater than threshold when the value of signal S1 When value T1, the second controllable switch (11) is changed from closed configuration to open configuration, and when the value of signal S1 is less than threshold value T1 When, the second controllable switch (11) is changed from open configuration to closed configuration.

10. a kind of filter system comprising protection system (1) according to any one of the preceding claims and electrolysis electricity Container (109), wherein current divider (2) is inserted between electrolytic capacitor (109) and reference potential.

11. a kind of motor comprising rotor, stator, the shell for accommodating stator and the electronics of the operation for monitoring motor Control card (101), the motor include filter system according to claim 10.

12. motor according to claim 11, wherein electronic card (101) includes filter system (1).

13. motor according to claim 11 or 12, wherein electronic control card (101) includes the power supply line along motor Inductance filter element (107), electrolytic capacitor (109) is connected to the electricity between inductance element (107) and the power supply of motor Source route.

14. motor described in any one of 1 to 13 according to claim 1 comprising for closing shell to form sealing shell (102) lid, filter system (1) are enclosed in sealing shell (102).