[summary of the invention]
The object of the present invention is to provide a kind of method and detection protective circuit that can detect power module secondary internal short-circuit in real time, overcome the defective of prior art.
The technical solution adopted for the present invention to solve the technical problems is: detect the guard method of power module outlet internal short-circuit, comprise the steps:
S11 detects a certain section voltage with circuit of fixed resistance on the power module output loop in real time, and whether the direction of judge module output current and size are short-circuited with the judge module outlet internal;
When S12 is short-circuited, close main power inverter, disconnect controlled disengaging unit, and report fault.
Among the step S11, flow back to module output low level end by module output high level end via the module-external circuit if judge electric current, then judge module is normal;
Flow back to module output high level end by module output low level end via the module-external circuit if judge electric current, and current value is less than a preset value, then judge module is normal;
Flow back to module output high level end by module output low level end via the module-external circuit if judge electric current, and current value is greater than preset value, then short trouble appears in the judge module outlet internal.
The inventive method also comprises the steps:
Whether secondary breaks away from the unit voltage of any before on real-time detection of the while power module output loop, export under-voltage with judgement.
If judge that output is under-voltage, report under-voltage fault.
The present invention also provides a kind of power module secondary internal short-circuit to detect protective circuit, comprises main control circuit, also comprises:
Output current detection circuit, be used for detecting in real time a certain section voltage on the power module output loop with circuit of fixed resistance, the direction of judge module output current and size, whether be short-circuited with the judge module outlet internal, when being short-circuited, close main power inverter, disconnect controlled disengaging unit, and corresponding output shutdown alarm signal reports fault to the main control circuit circuit.
Whether system of the present invention also comprises the output undervoltage detection circuit, is used for detecting in real time secondary on the power module output loop and breaks away from before the unit voltage of a bit, under-voltage to judge output, and corresponding output undervoltage alarm signal reports fault to the main control circuit circuit.
Described one section circuit with fixed resistance is positioned near module output port place.
One end of described circuit is a module output low level end, and the other end is the reference zero potential of module secondary.
One end of described circuit is a module output high level end, and the other end is on the module secondary output loop a bit, and described point is a path with fixing resistance value between module output high level end.
Described controlled disengaging unit is one or more the combination in relay, metal-oxide-semiconductor, circuit breaker, isolating switch, insurance, the fuse.
The present invention is worked by above-mentioned output current detection circuit and output undervoltage detection circuit one, can be under various service conditions, no matter whether export insurance is thrust, realization breaks away from the module that short trouble appears in outlet internal from system, and report fault: under the abundant condition of system's band storage battery or power-supply system module number in parallel in the undervoltage alarm mode, internal short circuit fault, export insurance are thrust when occurring, module when system breaks away from, realizes that module reports fault in the undervoltage alarm mode automatically; Under the fewer condition of module number in parallel, pass through output current detection circuit discrimination module outlet internal short-circuit with storage battery and power-supply system, realize shutting down, disconnect controlled disengaging unit and reporting module outlet internal short-circuit fault simultaneously.Improved the reliability of system's power supply.
[embodiment]
The embodiment of the invention is just set forth the operation principle of system of the present invention with the circuit of a kind of power module output loop shown in Figure 2.
Capacitor C 126 among Fig. 2, C125, C110 are output filter capacitors, and generally speaking the capacitance of capacitor C 126 is much larger than C110; F102 is an export insurance, at this as uncontrollable disengaging unit; K102 is an output relay, at this as controlled disengaging unit; Because the existence of C110, need be on output relay K102 and golden film resistance R124; L106 is the output common mode inductance; C128, C129 are Y electric capacity; L108, C127 are LC filtering, carry out filtering at characteristic frequency.When disconnecting controlled disengaging unit K102, diode D112 is used for the output relay coil short.
A kind of power module secondary internal short-circuit detects protective circuit, comprises main control circuit, output current detection circuit and output undervoltage detection circuit.
Output current detection circuit, be used for detecting in real time a certain section voltage on the power module output loop with circuit of fixed resistance, direction and size with the judge module output current, whether thereby judging the module outlet internal is short-circuited, and corresponding output shutdown alarm signal reports fault to main control circuit.Wherein, above-mentioned one section circuit with fixed resistance is preferably in to be positioned near module output port (module output high level end OUT+ or module output low level end OUT-) and locates, can comprise one of copper sheet, magnetic element lead, resistance, insurance etc. or its combination on the circuit, as long as this section circuit has fixed resistance.
Whether the output undervoltage detection circuit is used for detecting in real time secondary on the power module output loop and breaks away from before the unit voltage of a bit, under-voltage to judge output, and corresponding output undervoltage alarm signal is to main control circuit.Why undervoltage alarm point is taken at secondary breaks away from before the unit, be because a plurality of power modules when in parallel or during the band storage battery, insurance after a certain power module internal short-circuit, fuse etc. can be thrust, therefore the voltage after insurance, the fuse may be normal, but voltage before can't be set up.Break away from unit part afterwards in the power module output loop if short trouble occurs in, module itself can't break away from from system automatically.Wherein, break away from the unit and be divided into two kinds of controlled disengaging unit and uncontrollable disengaging unit.Controlled disengaging unit comprises relay, metal-oxide-semiconductor, circuit breaker, isolating switch etc., and uncontrollable disengaging unit comprises insurance, fuse etc.
Main control circuit is used for the various signals of importing it are handled, and closes main power inverter, the controlled disengaging of disconnection unit accordingly, alarms and report operations such as fault.
With specific embodiment the present invention is further elaborated with reference to the accompanying drawings below.
Embodiment one:
Described one section end with circuit of fixed resistance is a module output low level end (OUT-), and the other end is the reference zero position (GND1 among Fig. 2) of module secondary.The undervoltage alarm point is taken at the VO1 point among Fig. 2.
As shown in Figure 3, output current detection circuit mainly comprises power amplifier U1 and U2.The normal phase input end of power amplifier U1 links to each other with reference zero position GND1 point among Fig. 2 with the first predeterminated voltage VREF with resistance R 506 by resistance R 505 respectively, its inverting input links to each other with power module reversed-phase output OUT-among Fig. 2 with the first predeterminated voltage VREF with resistance R 508, R509 by resistance R 507 respectively, and its output links to each other with the normal phase input end of power amplifier U2 by resistance R 510.The inverting input of power amplifier U2 links to each other with the second predeterminated voltage VREF2, and its normal phase input end links to each other with the end of filter capacitor C502, the negative electrode of diode D501 simultaneously, and its output links to each other with the anode of diode D501.The other end ground connection of filter capacitor C502.Also comprise diode D502, its anode links to each other with the anode of diode D501, and its negative electrode links to each other with main control circuit as the output of output current detection circuit.Also comprise filter capacitor C501, the one end links to each other with the inverting input of power amplifier U1, other end ground connection.
The operation principle of foregoing circuit is: when power module normally moves, the level of its negative sense output OUT-will be higher than the level of the reference zero position GND1 of module secondary, represents electric current to flow back to module output low level end OUT-by module output high level end OUT+ via the module-external circuit.And the level of OUT-is lower than the level of GND1 when power module generation secondary internal short-circuit, and on behalf of electric current, current value flow back to module output high level end OUT+ by module output low level end OUT-via the module-external circuit greater than the pairing load current value of the first predeterminated voltage VREF.When the level of OUT-is lower than the level of GND1, but current value during less than the pairing load current value of the first predeterminated voltage VREF thinks that also module normally moves.This be because: in order to realize the hot plug function of power module, when power-supply system in when work, carry out the replacing of module this moment, system busbar can be to the output capacitance charging of the power module of new insertion, this sense of current is opposite with the normal current direction, and the size of this electric current and system busbar voltage, golden film resistance R124 are relevant.This electric current is generally less than 10% of amount of exports fixed load current values, and direction is opposite with normal current, often is taken at about 0.5A in the engineering.The mode that realizes hot plug has multiple scheme, and the scheme that has does not have reverse irrigated current, just first preset value can be made as zero this moment.When module just often, the output of power amplifier U2 is exported a low level, does not trigger the actuating circuit of main control circuit.When module secondary internal short-circuit, the output of power amplifier U2 output high level triggers the actuating circuit in the main control circuit, make main control circuit send signal, directly turn off main power circuit, and disconnect controlled disengaging unit (being relay K 102 among Fig. 2), simultaneously alarm.Because fault in case be short-circuited, export insurance, fuse may be thrust, the level of OUT-just equals the level of GND1 at this moment, cause the output of power amplifier U1 to become low level, but because the output of power amplifier U2 pours in down a chimney to its normal phase input end by diode D501, therefore its output can keep high level output, the influence that not changed by the OUT-signal.
Generally speaking, the pin of the existing high level shutdown of the main control chip in the main control circuit circuit, also there is low level to shield the pin that main power circuit drives, what select for use in the present embodiment is the pin of high level shutdown, therefore power amplifier U2 to main control chip, directly turns off main power circuit by diode D502.
In actual application, because misoperation, perhaps reasons such as equipment fault outside the power module, power module outlet is received on the equipment of voltage very high (being generally with respect to more than 1.5 times of himself output voltage), the breakdown short circuit of the output components and parts of power module meeting at this moment, export insurance is thrust, and this moment output current direction and size detection actuating circuit because the intrinsic time-delay of its device or add the time-delay that filtering measures introduces and cause this circuit may have little time action for avoiding interference, can't realize fault detect and alarm, therefore need the output undervoltage detection circuit to replenish.
As shown in Figure 4, the output undervoltage detection circuit mainly comprises power amplifier U3, its normal phase input end links to each other with the first predeterminated voltage VREF by resistance R 511, and its inverting input links to each other with undervoltage alarm point (the VO1 point among Fig. 2) by resistance R 272D, and its output links to each other with main control circuit.Also comprise resistance R 512, be connected across between the normal phase input end and output of power amplifier U3.Also comprise resistance R 281D, the one end links to each other with the inverting input of power amplifier U3, other end ground connection.Output voltage is very low when the module outlet internal short-circuit, the output undervoltage detection circuit can detect under-voltage: when module output voltage during less than the first predeterminated voltage VREF, power amplifier U3 will export a high level, trigger the warning circuit in the main control circuit, report under-voltage fault, but do not shut down, do not disconnect controlled disengaging unit yet.
Embodiment two:
Identical among the circuit structure of output undervoltage detection circuit and operation principle and the embodiment one in the present embodiment.Described one section end with circuit of fixed resistance is a module output high level end (OUT+), and the other end is on the module secondary output loop a bit, adopts the VO3 point in Fig. 2 circuit in the present embodiment.
As shown in Figure 5, output current detection circuit mainly comprises power amplifier U4, U5 and U6.The normal phase input end of power amplifier U4 respectively by resistance R 486, resistance R 485 and capacitor C 303 and module output high level end OUT+, link to each other with its inverting input, its inverting input links to each other with its output with VO3 point in Fig. 2 circuit by resistance R 493 and resistance R 494 respectively, its output links to each other with the normal phase input end of power amplifier U5 by resistance R 664, its positive power source terminal links to each other with an end of power supply VCC1 and capacitor C 442, and its negative power end links to each other with an end of power supply VCC3 and capacitor C 443.The other end ground connection of capacitor C 442 and capacitor C 443.The normal phase input end of power amplifier U5 is by capacitor C 379 ground connection, its inverting input is by resistance R 514 ground connection, its output links to each other with the normal phase input end of power amplifier U6 by resistance R 510, and its positive power source terminal links to each other with power supply VCC1, and its negative power end links to each other with power supply VCC3.The normal phase input end of power amplifier U6 passes through capacitor C 502 ground connection, and links to each other with the negative electrode of diode D501, and its inverting input links to each other with the second predeterminated voltage VREF2, and its output links to each other with the anode of diode D501.Also comprise diode D502, its anode links to each other with the anode of diode D501, and its negative electrode links to each other with main control circuit as the output of output current detection circuit.Wherein, power supply VCC3 is the negative supply with respect to the reference zero position GND1 of module secondary.
The operation principle of foregoing circuit is: when power module normally moved, the level of its positive output end OUT+ will be lower than the level that VO3 is ordered, and represented electric current to flow back to module output low level end OUT-by module output high level end OUT+ via the module-external circuit.And the level of OUT+ is higher than the level that VO3 is ordered when power module generation secondary internal short-circuit, represents electric current to flow back to module output high level end OUT+ by module output low level end OUT-via the module-external circuit.When module just often, the output of power amplifier U6 is exported a low level, does not trigger the actuating circuit of main control circuit.When module secondary internal short-circuit, power amplifier U6 pours in down a chimney to its normal phase input end by diode D501 owing to the output of power amplifier U6 simultaneously, so its output can keep high level output, the influence that not changed by the OUT+ signal.
Generally speaking, the pin of the existing high level shutdown of the main control chip in the main control circuit circuit, also there is low level to shield the pin that main power circuit drives, what select for use in the present embodiment is the pin of high level shutdown, therefore power amplifier U6 to main control chip, directly turns off main power circuit by diode D502.
In sum, invention thinking of the present invention is to work by above-mentioned output current detection circuit and output undervoltage detection circuit one, can be under various service conditions, no matter whether export insurance is thrust, realization breaks away from the module that short trouble appears in outlet internal from system, and report fault: under the abundant condition of system's band storage battery or power-supply system module number in parallel in the undervoltage alarm mode, internal short circuit fault, export insurance are thrust when occurring, module when system breaks away from, realizes that module reports fault in the undervoltage alarm mode automatically; Under the fewer condition of module number in parallel, pass through output current detection circuit discrimination module outlet internal short-circuit with storage battery and power-supply system, realize shutting down, disconnect controlled disengaging unit and reporting module outlet internal short-circuit fault simultaneously.
The above only is the preferred embodiments of the present invention, and for a person skilled in the art, circuit of the present invention can have various changes and variation.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within the claim scope of the present invention.