CN113037068A - Capacitor discharge circuit and power conversion circuit - Google Patents
Capacitor discharge circuit and power conversion circuit Download PDFInfo
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- CN113037068A CN113037068A CN202110496403.XA CN202110496403A CN113037068A CN 113037068 A CN113037068 A CN 113037068A CN 202110496403 A CN202110496403 A CN 202110496403A CN 113037068 A CN113037068 A CN 113037068A
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- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
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Abstract
The invention provides a capacitor discharge circuit and a power conversion circuit, which are applied to the technical field of power electronics. Compared with the prior art, the capacitor discharge circuit provided by the invention is provided with the residual voltage discharge circuit specially used for discharging the residual voltage of the bus capacitor, and the voltage of the bus capacitor is not released slowly by leakage current, so that the discharge time of the bus capacitor can be effectively shortened, and the discharge efficiency is improved.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a capacitor discharge circuit and a power conversion circuit.
Background
In order to reduce the voltage fluctuation of the direct current side in the working process of the power conversion circuit and simultaneously complete the functions of filtering, energy storage, voltage stabilization and the like, a large-capacity bus capacitor is usually configured between the positive direct current bus and the negative direct current bus of the power conversion circuit. According to the relevant standard requirements in the industry, the voltage of the bus capacitor needs to be reduced to a safe voltage which does not endanger the personal safety within 5 minutes after the power conversion circuit is powered off, so that the personal safety is not threatened when the system is shut down and maintained.
To meet the requirement, most power conversion circuits are provided with a discharge circuit, see fig. 1, fig. 1 is a commonly used capacitor discharge circuit in the prior art, when the power conversion circuit normally operates, a SIGNAL provides a normal working SIGNAL, and a main discharge path corresponding to a discharge resistor R4 is closed; when the power conversion circuit needs to discharge, an active discharge SIGNAL is given at the SIGNAL, the switch tube Q1 is turned off, the switch tube Q2 is turned on, and the bus capacitor continuously discharges through the discharge resistor R4 to reduce the voltage of the bus capacitor.
However, in the practical application of the discharge circuit shown in fig. 1, as the bus capacitor discharges, the bus voltage gradually decreases, which causes the switching tube Q2 to be turned off due to insufficient driving voltage, and the discharge later period can only depend on a very small leakage current to discharge, which results in greatly prolonged discharge time and low discharge efficiency.
Disclosure of Invention
The invention provides a capacitor discharge circuit and a power conversion circuit, which are provided with a residual voltage discharge circuit specially used for discharging residual voltage, wherein a main discharge circuit controls the residual voltage discharge circuit to be in a conducting state under the condition that a turn-off signal is not received and the capacitor voltage is smaller than a voltage threshold value, so that the residual voltage of a bus capacitor is discharged, the discharge time is shortened, and the discharge efficiency is improved.
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
in a first aspect, the present invention provides a capacitor discharge circuit, including: a main discharge circuit and a residual voltage discharge circuit, wherein,
the main discharge circuit and the residual voltage discharge circuit are respectively connected between the positive electrode of the bus capacitor and the negative electrode of the bus capacitor;
the main discharge circuit is connected with the residual voltage discharge circuit;
and the main discharge circuit controls the residual voltage discharge circuit to be in a conducting state under the condition that the main discharge circuit does not receive a turn-off signal and the capacitor voltage is smaller than the voltage threshold.
Optionally, the main discharging circuit is in a conducting state when the main discharging circuit does not receive the turn-off signal and the capacitor voltage is greater than or equal to the voltage threshold.
Optionally, the main discharging circuit is in an off state when receiving the off signal, and controls the residual voltage discharging circuit to be in the off state.
Optionally, the main discharge circuit includes: a master control circuit, a slave control circuit, and a master bleed circuit, wherein,
the master control circuit, the slave control circuit and the master bleeding circuit are connected in series;
the main control circuit switches working states according to the turn-off signal and the capacitor voltage, wherein the working states comprise a conducting state and a turn-off state;
the slave control circuit controls the working state of the residual voltage discharge circuit;
and the main discharge circuit discharges the electric energy stored by the bus capacitor under the condition that the capacitor voltage is greater than or equal to the voltage threshold.
Optionally, the main control circuit includes: a first controllable switch, a voltage divider circuit, a first driver circuit and a second controllable switch, wherein,
the first controllable switch is connected between the slave control circuit and the negative electrode of the bus capacitor in series;
the control end of the first controllable switch is connected with the voltage division output end of the voltage division circuit through the driving circuit;
the voltage division circuit is connected between the positive electrode of the bus capacitor and the negative electrode of the bus capacitor in series;
the second controllable switch is connected between the voltage division output end and the negative electrode of the bus capacitor, and the control end of the second controllable switch is used for receiving the turn-off signal.
Optionally, the first driving circuit includes: a zener diode and a first zener capacitor, wherein,
the voltage stabilizing diode is connected with the first voltage stabilizing capacitor in parallel to form a first parallel branch;
one end of the first parallel branch is connected with the voltage division output end, and the other end of the first parallel branch is connected with the negative electrode of the bus capacitor.
Optionally, the slave control circuit includes: a flyback converter circuit, wherein,
the input end of the flyback conversion circuit is connected in series between the main bleeder circuit and the main control circuit;
the output end of the flyback conversion circuit is connected with the residual voltage discharge circuit;
the flyback conversion circuit stores driving electric energy when the main control circuit is in a conducting state, and controls the residual voltage discharge circuit to be in the conducting state by using the driving electric energy after the main control circuit is switched from the conducting state to the turn-off state.
Optionally, the flyback converter circuit includes: a flyback transformer, a first anti-reverse diode, and a second drive circuit, wherein,
two ends of a primary winding of the flyback transformer are used as input ends of the flyback conversion circuit;
the secondary winding of the flyback transformer is connected with the second driving circuit through the first anti-reverse diode;
and the output end of the second driving circuit is used as the output end of the flyback conversion circuit.
Optionally, the second driving circuit includes: a voltage stabilizing resistor and a second voltage stabilizing capacitor, wherein,
the voltage stabilizing resistor is connected with the second voltage stabilizing capacitor in parallel to form a second parallel branch;
one end of the second parallel branch is connected with the negative electrode of the first anti-reverse diode, and the other end of the second parallel branch is connected with the tail end of the secondary winding;
and two ends of the second parallel branch are used as the output end of the second driving circuit.
Optionally, the main bleeding circuit comprises at least one bleeding resistor.
Optionally, the residual voltage discharge circuit includes: a third controllable switch and a slave bleed-off circuit, wherein,
the third controllable switch and the slave bleeder circuit are connected in series to form a series branch;
one end of the series branch is connected with the positive electrode of the bus capacitor, and the other end of the series branch is connected with the negative electrode of the bus capacitor;
and the control end of the third controllable switch is connected with the main discharge circuit.
Optionally, the slave bleed-off circuit comprises at least one bleed-off resistor.
Optionally, the capacitor discharge circuit provided in any one of the first aspect of the present invention further includes: a second anti-inversion diode and a third anti-inversion diode, wherein,
the positive electrode of the second anti-reverse diode is connected with the positive electrode of the bus capacitor;
the negative electrode of the third anti-reflection diode is connected with the negative electrode of the bus capacitor;
the main discharge circuit and the residual voltage discharge circuit are respectively connected between the cathode of the second anti-reverse diode and the anode of the third anti-reverse diode.
In a second aspect, the invention provides a power conversion circuit, comprising a main power conversion circuit and the capacitor discharge circuit of any one of the first aspect of the invention, wherein,
a direct current bus of the power conversion main circuit is connected with a bus capacitor;
and the capacitor discharge circuit is connected with the bus capacitor.
Optionally, the power conversion main circuit includes one of an inverter circuit, a rectifier circuit and a DC/DC conversion circuit.
The invention provides a capacitor discharge circuit, comprising: the main discharging circuit and the residual voltage discharging circuit are respectively connected between the positive electrode of the bus capacitor and the negative electrode of the bus capacitor, the main discharging circuit is connected with the residual voltage discharging circuit, and the main discharging circuit controls the residual voltage discharging circuit to be in a conducting state and discharges the voltage of the bus capacitor under the condition that a turn-off signal is not received and the capacitor voltage is smaller than a voltage threshold value. Compared with the prior art, the capacitor discharge circuit provided by the invention is provided with the residual voltage discharge circuit specially used for discharging the residual voltage of the bus capacitor, and the voltage of the bus capacitor is not released slowly by leakage current, so that the discharge time of the bus capacitor can be effectively shortened, and the discharge efficiency is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a circuit topology diagram of a prior art capacitor discharge circuit;
fig. 2 is a block diagram of a capacitor discharge circuit according to an embodiment of the present invention;
FIG. 3 is a block diagram of another capacitor discharge circuit according to an embodiment of the present invention;
FIG. 4 is a circuit topology diagram of a capacitor discharge circuit according to an embodiment of the present invention;
FIG. 5 is a circuit topology diagram of another capacitor discharge circuit provided by an embodiment of the invention;
fig. 6 is a circuit topology diagram of another capacitor discharge circuit according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
Referring to fig. 2, fig. 2 is a block diagram of a capacitor discharge circuit according to an embodiment of the present invention, where, as shown in fig. 2, BUS + represents an anode dc BUS, BUS-represents a cathode dc BUS, C0 represents a BUS capacitor, one end of the BUS capacitor C0 connected to the anode dc BUS is defined as a BUS capacitor anode, and correspondingly, one end of the BUS capacitor C0 connected to the cathode dc BUS is defined as a BUS capacitor cathode. Based on this, the capacitor discharge circuit provided by the present embodiment includes a main discharge circuit and a residual voltage discharge circuit, wherein,
the main discharge circuit and the residual voltage discharge circuit are respectively connected between the positive electrode of the bus capacitor and the negative electrode of the bus capacitor, and the main discharge circuit is also connected with the residual voltage discharge circuit.
It should be noted that, in this embodiment and the following embodiments, the main discharging circuit is used to discharge most of the electric energy in the bus capacitor C0, and the leakage current flowing during the operation is usually large, while the residual voltage discharging circuit is mainly used to discharge little electric energy remaining in the bus capacitor C0 when the capacitor voltage of the bus capacitor C0 is lower than the voltage threshold, and therefore, the leakage current flowing during the operation of the residual voltage discharging circuit is smaller than the current flowing during the operation of the main discharging circuit.
Based on the above, the main discharging circuit is in the on state when the turn-off signal is not received and the capacitor voltage is greater than or equal to the voltage threshold, the electric energy stored in the bus capacitor C0 is released by a relatively large discharging current, and when the turn-off signal is not received and the capacitor voltage is less than the voltage threshold, the residual voltage discharging circuit is controlled to be in the on state, and a small amount of electric energy remained in the bus capacitor C0 is released through the residual voltage discharging circuit.
It should be noted that, for the selection and setting of the voltage threshold, the voltage threshold is mainly related to the working voltage of the main discharge circuit, and generally, the lowest working voltage of the main discharge circuit may be used as the voltage threshold, but in order to ensure that the main discharge circuit can effectively control the conduction of the residual voltage discharge circuit, the voltage threshold may be slightly larger than the lowest working voltage of the main discharge circuit, and for the specific setting of the voltage threshold, the specific circuit parameters of the main discharge circuit and the residual voltage discharge circuit may be flexibly selected in combination, which is not limited in this invention.
Optionally, the main discharge circuit is in an off state when receiving the off signal, and the residual voltage discharge circuit is controlled to be in the off state at the same time, that is, when receiving the off signal, both the main discharge circuit and the residual voltage discharge circuit are in the off state, and the bus capacitor C0 is not discharged, so that the normal operation of the bus capacitor C0 and the power conversion circuit to which the bus capacitor C0 belongs is ensured.
For the shutdown signal, it can be known by combining the working principle of the bus capacitor discharge circuit in the prior art that, when the power conversion circuit to which the bus capacitor C0 belongs is in a normal operation state, the control circuit of the power conversion circuit may continuously send the shutdown signal to the main discharge circuit, and for specific implementation, the continuously sent shutdown signal may be a high level. Correspondingly, when the power conversion circuit needs to be powered off or is powered off due to a fault, the shutdown signal cannot be continuously sent any more, the prior example is used, the main discharging circuit does not receive the shutdown signal, namely, the corresponding input end does not input a high level any more, namely, the invention relates to two possible situations that the power conversion circuit cannot continuously send the shutdown signal due to the power failure.
In summary, in the capacitor discharge circuit provided in the embodiments of the present invention, the main discharge circuit controls the residual voltage discharge circuit to be in the on state and discharge the voltage of the bus capacitor when the main discharge circuit does not receive the turn-off signal and the capacitor voltage is smaller than the voltage threshold. Compared with the prior art, the capacitor discharge circuit provided by the invention is provided with the residual voltage discharge circuit specially used for discharging the residual voltage of the bus capacitor, and the voltage of the bus capacitor is not released slowly by leakage current, so that the discharge time of the bus capacitor can be effectively shortened, and the discharge efficiency is improved.
Optionally, referring to fig. 3, fig. 3 is a block diagram of another structure of a capacitor discharge circuit according to an embodiment of the present invention, and on the basis of the embodiment shown in fig. 2, this embodiment mainly provides an optional configuration of a main discharge circuit, and mainly includes: a master control circuit, a slave control circuit, and a master bleed circuit, wherein,
the main control circuit, the slave control circuit and the main bleeder circuit are connected in series, the obtained series branch is connected between the positive pole of the bus capacitor and the negative pole of the bus capacitor, and the specific connection sequence of the main control circuit, the slave control circuit and the main bleeder circuit can be flexibly selected by combining the actual conditions and is not expanded.
In practical applications, the master control circuit is configured to switch an operating state according to the shutdown signal and the capacitor voltage of the bus capacitor C0, specifically, the operating state of the master control circuit includes an on state and an off state, and the slave control circuit is configured to control the operating state of the residual voltage discharge circuit.
In combination with the above, the master control circuit is in an off state when receiving the off signal, and the slave control circuit controls the residual voltage discharge circuit to be also in the off state, and correspondingly, the master control circuit is in an on state when not receiving the off signal and the capacitor voltage is greater than or equal to the voltage threshold, so that most of the electric energy of the bus capacitor can flow through the master bleeding circuit and be bled. And when the capacitor voltage is lower than a voltage threshold value, the slave control circuit controls the residual voltage discharge circuit to be conducted, and the residual voltage discharge circuit releases the electric energy remained in the bus capacitor.
The following describes an alternative configuration of the capacitor discharge circuit provided by the present invention with reference to a specific circuit topology.
Referring to fig. 4, fig. 4 is a circuit topology diagram of a capacitor discharge circuit according to an embodiment of the present invention, and this embodiment specifically illustrates an optional configuration of a main discharge circuit. Specifically, the main control circuit in the main discharge circuit includes a first controllable switch Q1, a voltage dividing circuit, a first driving circuit, and a second controllable switch U1, wherein,
the voltage division circuit comprises a first voltage division circuit R1 and a second voltage division circuit R2 which are connected in series, one end of the voltage division branch circuit is connected with the positive pole of the bus capacitor, the other end of the voltage division branch circuit is connected with the negative pole of the bus capacitor, and the connection point of the first voltage division branch circuit R1 and the second voltage division branch circuit R2 is the voltage division output end of the voltage division circuit.
It is understood that, in this and subsequent embodiments, the first voltage-dividing branch R1 and the second voltage-dividing branch R2 may be composed of at least one resistor or other element capable of releasing current, and the structure shown in fig. 3 is only an exemplary illustration of the structure of the voltage-dividing circuit, and is not a limitation to the specific structure of the voltage-dividing circuit, and modifications made on the basis of this structure are also within the scope of the present invention without departing from the scope of the core idea of the present invention.
Optionally, the first driving circuit includes a zener diode Dw and a first zener capacitor C1. The voltage stabilizing diode Dw is connected with a first voltage stabilizing capacitor C1 in parallel to form a first parallel branch, one end of the first parallel branch is connected with the voltage dividing output end of the voltage dividing circuit, and the other end of the first parallel branch is connected with the cathode of the bus capacitor.
Further, based on the specific structure of the voltage dividing circuit and the driving circuit, the first controllable switch Q1 is connected in series between the slave control circuit (the specific structure is subsequently developed) and the negative electrode of the bus capacitor, and the control end is connected with the voltage dividing output end of the voltage dividing circuit through the driving circuit. Specifically, in the embodiment shown in fig. 4, the first controllable switch Q1 is implemented based on a MOS transistor, the drain of the first controllable switch Q1 is connected to the slave control circuit, the source is connected to the cathode of the bus capacitor, and the gate is connected as the control terminal of the first controllable switch Q1 to the connection point of the driving circuit, i.e., the zener diode Dw and the first zener capacitor C1.
The second controllable switch U1 is realized based on an optocoupler relay, the output end of the second controllable switch U1 is connected between the voltage division output end and the negative electrode of the bus capacitor, and the control end of the second controllable switch is used for receiving the turn-off signal.
Optionally, the slave control circuit is implemented based on a flyback converter circuit, an input end of the flyback converter circuit is connected in series between the main bleeder circuit and the main control circuit, and an output end of the flyback converter circuit is connected to the residual voltage discharge circuit to output a corresponding control signal to the residual voltage discharge circuit. The flyback conversion circuit stores driving electric energy when the main control circuit is in a conducting state, and controls the residual voltage discharge circuit to be in the conducting state by using the stored driving electric energy after the main control circuit is switched from the conducting state to the turn-off state. Therefore, the slave control circuit cannot continuously control the state of the residual voltage discharge circuit, and the residual voltage discharge circuit is not controlled to be in a conducting state when a certain condition is met along with the consumption of self stored energy. Because of this, in practical applications, the effective operating time of the slave control circuit should be selected and calculated in conjunction with the specific power conversion circuit.
Based on the above, fig. 4 also shows an alternative configuration of the slave control circuit, and the slave control circuit in this embodiment includes: a flyback transformer T1, a first anti-flyback diode D1, and a second drive circuit, wherein,
the second driving circuit includes a voltage stabilizing resistor Rf and a second voltage stabilizing capacitor C2. The voltage stabilizing resistor Rf and the second voltage stabilizing capacitor C2 are connected in parallel to form a second parallel branch, one end of the obtained second parallel branch is connected with the negative electrode of the first anti-reverse diode D1, the other end of the second parallel branch is connected with the tail end of the secondary winding of the flyback transformer T1, and meanwhile, the two ends of the second parallel branch are used as the output end of the second driving circuit.
Two ends of a primary winding of the flyback transformer T1 are used as input ends of a flyback conversion circuit and are respectively connected to the main control circuit and the main discharge circuit, specifically, a head end of the primary winding is connected to a drain electrode of a first switch tube Q1 in the main control circuit, and a tail end of the primary winding is connected to the main discharge circuit. The secondary winding of the flyback transformer is connected with a second driving circuit, namely a connection point of a voltage stabilizing resistor Rf and a second voltage stabilizing capacitor C2, through a first anti-reverse diode D1.
The output end of the second driving circuit is used as the output end of the flyback conversion circuit and is connected with the residual voltage discharge circuit to control the working state of the residual voltage discharge circuit.
Similar to the first voltage dividing branch R1 and the second voltage dividing branch R2 in the voltage dividing circuit, the main bleeding circuit R3 shown in fig. 4 includes at least one bleeding resistor, and when the main bleeding circuit R3 is composed of a plurality of bleeding resistors, the main bleeding circuit R3526 may be connected in series and/or in parallel according to the specific bleeding resistance requirement, which is not limited in the present invention.
Optionally, referring to fig. 5, fig. 5 is a circuit topology diagram of another capacitor discharge circuit provided in the embodiment of the present invention, and on the basis of the embodiment shown in fig. 4, the present embodiment provides an optional configuration of the residual voltage discharge circuit.
Specifically, as shown in fig. 5, the residual voltage discharge circuit includes a third controllable switch Q2 and a slave bleeder circuit R4 including at least one bleeder resistor. The third controllable switch Q2 and the slave bleeder circuit R4 are connected in series to form a series branch, one end of the series branch is connected to the positive pole of the bus capacitor, and the other end of the series branch is connected to the negative pole of the bus capacitor.
Optionally, the third controllable switch Q2 is implemented based on a MOS transistor, a drain of the third controllable switch Q2 is connected to the slave bleeder circuit R4, a source of the third controllable switch Q2 is connected to a cathode of the bus capacitor and an output terminal of the second driving circuit, and a control terminal of the third controllable switch Q2, that is, a gate of the third controllable switch Q2 is connected to the slave control circuit in the master discharge circuit, specifically, to the other terminal of the second driving circuit in the slave control circuit.
For the structure of the slave bleeding circuit, the master bleeding circuit can be referred to for implementation, and details are not described here.
The following describes the selection of some components in the capacitive discharge circuit and the operation process of the circuit in conjunction with the embodiments shown in fig. 4 and fig. 5.
The main bleeder circuit is realized by a bleeder resistor with the resistance value of kiloohm level; the voltage dividing resistor in the voltage dividing circuit is realized by a resistor with the resistance value of megaohm level; the slave bleeder circuit is realized by selecting a bleeder resistor with the resistance value of ten kilohm level.
When the power conversion circuit normally operates, the voltage of a bus capacitor is about 1500V, and the direct-current bus capacitor of the system does not need to discharge; at this moment, the second controllable switch, that is, the optocoupler relay U1 receives a turn-off signal of a high level, the optocoupler relay is turned on, and the pin 4 output of the optocoupler relay is pulled down to 0V, so that the driving end voltage of the first controllable switch Q1 is a low level, and the main discharge circuit is turned off and does not discharge to the bus capacitor. Meanwhile, no current flows through the flyback transformer T1, the voltage at the driving end of the third controllable switch Q2 is clamped at a low level, and the residual voltage discharge circuit is also turned off; under the condition, only a small leakage current flows through the voltage division circuit, and the normal work of the bus capacitor cannot be influenced.
When the power conversion circuit needs to be powered off and stops outputting a turn-off signal, namely the input pin 1 of the optocoupler relay U1 is connected with a low level, and the optocoupler relay is not switched on at the moment. The voltage division output end of the voltage division circuit outputs divided voltage, under the condition that the voltage of a bus capacitor is about 1500V, the initial value of the divided voltage is a certain value which is not larger than the maximum input voltage of the normal work of a voltage regulator tube D1, the driving voltage of a first controllable switch Q1 is clamped at about 15V through the voltage regulator tube D1, the first controllable switch Q1 is conducted, and the energy of the bus capacitor is discharged through a main discharge circuit, a primary winding of a flyback transformer T1 and a first controllable switch Q1. Meanwhile, according to the basic operation principle of the flyback transformer, the primary winding of the flyback transformer T1 stores a certain amount of energy. When the voltage value output to the driving end of the first controllable switch Q1 by the voltage dividing circuit is lower than the turn-off value of the first controllable switch Q1, the first controllable switch Q1 is turned off, the energy of the primary winding of the flyback transformer T1 is converted into the secondary winding, the third controllable switch Q2 is driven to be turned on, the residual voltage discharging circuit is turned on, and the bus capacitor completes the discharge of the residual voltage through the discharge circuit R4 and the third controllable switch Q2. Because the resistance of the voltage stabilizing resistor Rf is large enough and the third controllable switch Q2 is a voltage-type driving device, the energy of the secondary winding of the flyback transformer T1 can support the third controllable switch Q2 to be turned on for a longer time, and the energy of the capacitor is released.
When the power conversion system fails or the controller outputting the shutdown signal is suddenly powered off and the shutdown signal cannot be given, the capacitor bus needs to be discharged, and the working process is consistent with the above contents, which is not described herein again.
Optionally, in order to ensure the normal operation of the discharge circuit, an anti-reverse diode may be further provided in the discharge circuit. Specifically, referring to fig. 6, fig. 6 is a circuit topology diagram of another capacitor discharge circuit according to an embodiment of the present invention, and based on any of the above embodiments (taking the embodiment shown in fig. 5 as an example in the figure), the capacitor discharge circuit according to this embodiment further includes: a second anti-bounce diode D2 and a third anti-bounce diode D3, wherein,
the anode of the second anti-reverse diode D2 is connected with the anode of the bus capacitor; the negative electrode of the third anti-explosion diode D3 is connected with the negative electrode of the bus capacitor; the main discharge circuit and the residual voltage discharge circuit are respectively connected between the cathode of the second anti-reflection diode D2 and the anode of the third anti-reflection diode D3.
Based on the above, it can be seen that the capacitor discharge circuit provided in the embodiments of the present invention not only can maintain the electric energy discharge under the condition of higher bus capacitor voltage in the prior art, but also can open up a new residual voltage discharge path to complete the residual voltage discharge when the main discharge circuit cannot provide the driving voltage for the discharge power tube because of lower capacitor voltage.
Furthermore, in each embodiment of the invention, the residual voltage discharge circuit utilizes the basic principle of the flyback circuit, has the characteristics of high reliability and simple circuit, does not need to be additionally provided with a high-voltage input switching power supply, does not need to obtain alternating current from the outside, and has the realization cost far lower than that of the existing scheme.
Finally, the circuit control logic is simple, only one path of control signal (namely a turn-off signal) is needed, and the circuit stability is high.
Optionally, an embodiment of the present invention further provides a power conversion circuit, including a main power conversion circuit and the capacitor discharge circuit according to any one of the above embodiments of the present invention, wherein,
a direct current bus of the power conversion main circuit is connected with a bus capacitor;
and the capacitor discharge circuit is connected with the bus capacitor.
Optionally, the power conversion main circuit includes one of an inverter circuit, a rectifier circuit and a DC/DC conversion circuit.
The embodiments of the invention are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments can be referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.
Claims (15)
1. A capacitive discharge circuit, comprising: a main discharge circuit and a residual voltage discharge circuit, wherein,
the main discharge circuit and the residual voltage discharge circuit are respectively connected between the positive electrode of the bus capacitor and the negative electrode of the bus capacitor;
the main discharge circuit is connected with the residual voltage discharge circuit;
and the main discharge circuit controls the residual voltage discharge circuit to be in a conducting state under the condition that the main discharge circuit does not receive a turn-off signal and the capacitor voltage is smaller than the voltage threshold.
2. The capacitive discharge circuit of claim 1 wherein the main discharge circuit is in a conducting state if the turn-off signal is not received and the capacitive voltage is greater than or equal to the voltage threshold.
3. The capacitive discharge circuit of claim 2, wherein the main discharge circuit is in an off state upon receiving the off signal and controls the residual voltage discharge circuit to be in an off state.
4. The capacitive discharge circuit of claim 1 wherein said main discharge circuit comprises: a master control circuit, a slave control circuit, and a master bleed circuit, wherein,
the master control circuit, the slave control circuit and the master bleeding circuit are connected in series;
the main control circuit switches working states according to the turn-off signal and the capacitor voltage, wherein the working states comprise a conducting state and a turn-off state;
the slave control circuit controls the working state of the residual voltage discharge circuit;
and the main discharge circuit discharges the electric energy stored by the bus capacitor under the condition that the capacitor voltage is greater than or equal to the voltage threshold.
5. The capacitive discharge circuit of claim 4 wherein said main control circuit comprises: a first controllable switch, a voltage divider circuit, a first driver circuit and a second controllable switch, wherein,
the first controllable switch is connected between the slave control circuit and the negative electrode of the bus capacitor in series;
the control end of the first controllable switch is connected with the voltage division output end of the voltage division circuit through the driving circuit;
the voltage division circuit is connected between the positive electrode of the bus capacitor and the negative electrode of the bus capacitor in series;
the second controllable switch is connected between the voltage division output end and the negative electrode of the bus capacitor, and the control end of the second controllable switch is used for receiving the turn-off signal.
6. The capacitive discharge circuit of claim 5 wherein the first driver circuit comprises: a zener diode and a first zener capacitor, wherein,
the voltage stabilizing diode is connected with the first voltage stabilizing capacitor in parallel to form a first parallel branch;
one end of the first parallel branch is connected with the voltage division output end, and the other end of the first parallel branch is connected with the negative electrode of the bus capacitor.
7. The capacitive discharge circuit of claim 4 wherein the slave control circuit comprises: a flyback converter circuit, wherein,
the input end of the flyback conversion circuit is connected in series between the main bleeder circuit and the main control circuit;
the output end of the flyback conversion circuit is connected with the residual voltage discharge circuit;
the flyback conversion circuit stores driving electric energy when the main control circuit is in a conducting state, and controls the residual voltage discharge circuit to be in the conducting state by using the driving electric energy after the main control circuit is switched from the conducting state to the turn-off state.
8. The capacitive discharge circuit of claim 7, wherein the flyback converter circuit comprises: a flyback transformer, a first anti-reverse diode, and a second drive circuit, wherein,
two ends of a primary winding of the flyback transformer are used as input ends of the flyback conversion circuit;
the secondary winding of the flyback transformer is connected with the second driving circuit through the first anti-reverse diode;
and the output end of the second driving circuit is used as the output end of the flyback conversion circuit.
9. The capacitive discharge circuit of claim 8 wherein said second driver circuit comprises: a voltage stabilizing resistor and a second voltage stabilizing capacitor, wherein,
the voltage stabilizing resistor is connected with the second voltage stabilizing capacitor in parallel to form a second parallel branch;
one end of the second parallel branch is connected with the negative electrode of the first anti-reverse diode, and the other end of the second parallel branch is connected with the tail end of the secondary winding;
and two ends of the second parallel branch are used as the output end of the second driving circuit.
10. The capacitive discharge circuit of claim 4 wherein said main bleed circuit comprises at least one bleed resistor.
11. The capacitive discharge circuit of claim 1, wherein the residual voltage discharge circuit comprises: a third controllable switch and a slave bleed-off circuit, wherein,
the third controllable switch and the slave bleeder circuit are connected in series to form a series branch;
one end of the series branch is connected with the positive electrode of the bus capacitor, and the other end of the series branch is connected with the negative electrode of the bus capacitor;
and the control end of the third controllable switch is connected with the main discharge circuit.
12. The capacitive discharge circuit of claim 11 wherein said slave bleed circuit comprises at least one bleed resistor.
13. The capacitive discharge circuit of any of claims 1-12, further comprising: a second anti-inversion diode and a third anti-inversion diode, wherein,
the positive electrode of the second anti-reverse diode is connected with the positive electrode of the bus capacitor;
the negative electrode of the third anti-reflection diode is connected with the negative electrode of the bus capacitor;
the main discharge circuit and the residual voltage discharge circuit are respectively connected between the cathode of the second anti-reverse diode and the anode of the third anti-reverse diode.
14. A power conversion circuit comprising a main power conversion circuit and the capacitor discharge circuit according to any one of claims 1 to 13,
a direct current bus of the power conversion main circuit is connected with a bus capacitor;
and the capacitor discharge circuit is connected with the bus capacitor.
15. The power conversion circuit of claim 14, wherein the power conversion main circuit comprises one of an inverter circuit, a rectifier circuit and a DC/DC conversion circuit.
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| CN202110496403.XA CN113037068B (en) | 2021-05-07 | 2021-05-07 | Capacitor discharging circuit and power conversion circuit |
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| CN202110496403.XA CN113037068B (en) | 2021-05-07 | 2021-05-07 | Capacitor discharging circuit and power conversion circuit |
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| CN113037068B CN113037068B (en) | 2023-05-26 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100102638A1 (en) * | 2008-10-23 | 2010-04-29 | Gm Global Technology Operations, Inc. | Systems and methods for discharging bus voltage using semiconductor devices |
| CN204517648U (en) * | 2015-03-25 | 2015-07-29 | 阳光电源股份有限公司 | A kind of discharge circuit, charge-discharge circuit and inverter |
| CN106787657A (en) * | 2016-12-29 | 2017-05-31 | 上海新时达电气股份有限公司 | Vehicle-mounted drive control device capacitor discharging circuit |
| CN207691419U (en) * | 2017-12-01 | 2018-08-03 | 四川巨海渔业科技有限公司 | A kind of circuit released for bus-bar charge |
| CN210534294U (en) * | 2019-06-28 | 2020-05-15 | 北京天诚同创电气有限公司 | Fault monitoring system of backup power supply of super capacitor |
-
2021
- 2021-05-07 CN CN202110496403.XA patent/CN113037068B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100102638A1 (en) * | 2008-10-23 | 2010-04-29 | Gm Global Technology Operations, Inc. | Systems and methods for discharging bus voltage using semiconductor devices |
| CN204517648U (en) * | 2015-03-25 | 2015-07-29 | 阳光电源股份有限公司 | A kind of discharge circuit, charge-discharge circuit and inverter |
| CN106787657A (en) * | 2016-12-29 | 2017-05-31 | 上海新时达电气股份有限公司 | Vehicle-mounted drive control device capacitor discharging circuit |
| CN207691419U (en) * | 2017-12-01 | 2018-08-03 | 四川巨海渔业科技有限公司 | A kind of circuit released for bus-bar charge |
| CN210534294U (en) * | 2019-06-28 | 2020-05-15 | 北京天诚同创电气有限公司 | Fault monitoring system of backup power supply of super capacitor |
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| CN113037068B (en) | 2023-05-26 |
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