CN112803723B - Inverter control method, switching tube driving circuit, controller and inverter - Google Patents
Inverter control method, switching tube driving circuit, controller and inverter Download PDFInfo
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- CN112803723B CN112803723B CN202110001497.9A CN202110001497A CN112803723B CN 112803723 B CN112803723 B CN 112803723B CN 202110001497 A CN202110001497 A CN 202110001497A CN 112803723 B CN112803723 B CN 112803723B
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- H—ELECTRICITY
- 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
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
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- H—ELECTRICITY
- 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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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- H—ELECTRICITY
- 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
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
- H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
- H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Abstract
The scheme is that in the process of converting current of an inverter from a power diode to a switching tube, the switching tube is controlled to be conducted with different resistance values according to different running currents of the inverter, specifically, as the current value of the inverter is gradually reduced, the conduction resistance of the switching tube is gradually increased, so that the conduction speed of the switching tube is reduced, namely, the current conversion speed is reduced, the current change rate of the power diode during current conversion is reduced, and the reverse stress at two ends of the power diode is finally reduced. And when the current of the inverter is larger, the resistance value of the on-resistance of the switching tube is smaller, and the turn-on loss of the switching tube and the turn-off loss of the power diode are reduced, so that the high operation efficiency of the inverter is ensured.
Description
Technical Field
The invention belongs to the technical field of power electronics, and particularly relates to an inverter control method, a switching tube driving circuit, a controller and an inverter.
Background
The inverter works on the principle that a control transistor converts direct current into alternating current. In an inverter, a power diode and a switching tube are usually provided, and the power diode is mainly used in a boost circuit or an inverter circuit to provide a commutation loop for the switching tube. If the speed of the power diode converting to the switching tube is too high in the current converting process, the current change rate on the power diode is very high, and further the voltage stress of the power diode exceeds the standard, the voltage stress can be superposed on the switching tube converting to increase the voltage stress and loss of the switching tube, particularly under the condition of small current, the turn-off characteristic of the power diode is hard (namely, the turn-off speed is slow), and the problem of the exceeding of the voltage stress of the power diode is more serious under the condition.
The traditional solution is to use a soft recovery diode, which has a slow turn-off speed and a soft characteristic, so as to reduce the current change rate of the diode, but the soft recovery diode has high loss, which results in the reduction of the operation efficiency of the inverter.
Therefore, a solution that can effectively reduce the stress of the power diode without reducing the efficiency of the inverter is needed.
Disclosure of Invention
In view of the above, an object of the present invention is to provide an inverter control method, a switching tube driving circuit, a controller and an inverter, so as to reduce stress of a power diode in the inverter without reducing operation efficiency of the inverter, and the disclosed specific technical solution is as follows:
in a first aspect, the present application provides an inverter control method, including:
when the inverter is in a current conversion state from the power diode to the switching tube, obtaining inverter current;
comparing the inverter current with at least one current threshold value, and determining a target current interval in which the inverter current is located;
and determining a target resistance value of the switching-on resistor of the switching tube matched with the target current interval, and controlling the switching-on resistor of the switching tube to be the target resistance value, wherein the target resistance value is inversely related to the current value of the target current interval.
Optionally, a driving circuit of the switching tube is provided with a switching-on resistor branch with an adjustable resistance value;
the controlling the switching-on resistance of the switching tube to be the target resistance value comprises the following steps:
and adjusting the resistance value of the switching resistance branch circuit to be the target resistance value.
Optionally, the total number of the current intervals is N, the switching-on resistance branch comprises a second control switch and M resistors connected in series in sequence, and each resistor is connected in parallel with a first control switch,
represents rounding up;
the adjusting the resistance value of the switching-on resistance branch circuit to the target resistance value comprises:
and controlling the second control switch to be closed to open the opening resistance branch, and controlling the switch state of each first control switch so as to enable the sum of the resistance values of all the resistors connected to the opening resistance branch to be equal to the target resistance value.
Optionally, the switch tube is driven by the switch tubeM switching-on resistor branches with different resistance values are arranged in the circuit, the total number of the current intervals is N, wherein N is a positive integer greater than 1, and
represents rounding up;
the controlling the on resistance of the switch tube to be the target resistance value comprises the following steps:
controlling the resistance value to be the target resistance value and switching on the resistance branch circuit;
the target opening resistance branch is one opening resistance branch or a branch obtained by connecting at least two opening resistance branches in parallel.
Optionally, the current interval includes a first current interval and a second current interval, and a current value of the first current interval is smaller than a current value of the second current interval, the switching resistance branch includes a first switching resistance branch and a second switching resistance branch, and a resistance value of the first switching resistance branch is greater than a resistance value of the second switching resistance branch;
the controlling the on resistance of the switch tube to be the target resistance value comprises the following steps:
when the inverter current is in the first current interval, controlling the first switching-on resistance branch circuit to be conducted;
and when the inverter current is in the second current interval, controlling the second switching-on resistance branch circuit to be switched on.
Optionally, the current interval includes a first current interval and a second current interval, and a current value of the first current interval is smaller than a current value of the second current interval, and the open resistance branch of the switching tube includes a first open resistance branch and a second open resistance branch;
the controlling the on resistance of the switch tube to be the target resistance value comprises the following steps:
when the inverter current is in the first current interval, controlling the first switching-on resistance branch or the second switching-on resistance branch to be switched on;
and when the current of the inverter is in the second current interval, controlling the first switching-on resistance branch circuit and the second switching-on resistance branch circuit to be switched on.
In a second aspect, the present application further provides a switching tube driving circuit in an inverter, including: the control circuit is driven, and each switching tube needing current conversion is provided with at least one switching-on resistance branch and one switching-off resistance branch;
the opening driving end of the driving control circuit is connected with the at least one opening resistance branch circuit;
the turn-off driving end of the driving control circuit is connected with the turn-off resistance branch;
the control signal input end of the drive control circuit is connected with the controller of the inverter, and after the drive control circuit receives a switching-on resistance switching signal sent by the controller, the state of the at least one switching-on resistance branch circuit is controlled, so that the switching-on resistance of the switching tube is equal to a target resistance value;
the switching signal of the switching resistor is determined by the controller according to the current of the inverter and the current interval where the current of the inverter is located, and the current value of the current interval is inversely related to the target resistance value.
Optionally, the total number of the current intervals is N, where N is a positive integer greater than 1;
each switching tube needing current conversion is provided with a switching-on resistance branch, and the resistance value of the switching-on resistance branch is adjustable.
Optionally, the switching-on resistance branch comprises a second control switch and M resistors connected in series in sequence, each of the resistors is connected in parallel with a first control switch, wherein,
represents rounding up;
and obtaining N target resistance values matched with the N current intervals by combining at least one resistor in the M resistors.
Optionally, the total number of the current intervals is N, the number of the open resistance branches is M, N is a positive integer greater than 1, and
represents rounding up;
when the M is equal to N, the resistance value of each opening resistance branch is respectively matched with the N current intervals;
and when M is less than N, combining at least one of the M switching-on current branches to obtain N resistance values respectively matched with the N current intervals.
Optionally, the switching-on resistance branch of the switching tube includes: the circuit comprises a first switching resistor branch and a second switching resistor branch, wherein the resistance value of the first switching resistor branch is larger than that of the second switching resistor branch;
when the drive control circuit receives a first switching signal, the first switching resistance branch circuit is controlled to be conducted, and when the drive control circuit receives a second switching signal, the second switching resistance branch circuit is controlled to be conducted;
the first switching-on resistance switching signal is generated when the controller determines that the inverter current is in a first current interval smaller than a first preset current threshold, and the second switching-on resistance switching signal is generated when the controller determines that the inverter current is in a second current interval larger than or equal to the first preset current threshold.
Optionally, the switching-on resistance branch of the switching tube includes: a first open resistance branch and a second open resistance branch;
when the drive control circuit receives a first switching-on resistance switching signal, controlling the first switching-on resistance branch or the second switching-on resistance branch to be switched on; when the drive control circuit receives a second switching-on resistance switching signal, controlling the first switching-on resistance branch circuit and the second switching-on resistance branch circuit to be conducted;
the first switching-on resistance switching signal is generated when the controller determines that the inverter current is in a first current interval smaller than a first preset current threshold, and the second switching-on resistance switching signal is generated when the controller determines that the inverter current is in a second current interval larger than or equal to the first preset current threshold.
In a third aspect, the present application further provides a controller, comprising: a memory and a processor;
the memory has stored therein program instructions;
the processor calls program instructions in the memory to execute the inverter control method according to any one of the possible implementations of the first aspect.
In a fourth aspect, the present application further provides an inverter comprising: the control circuit comprises an inverter main circuit, a switching tube driving control circuit of any one possible implementation manner of the second aspect, and a controller of the third aspect.
According to the inverter control method, when the inverter is in a current conversion state that a power diode converts current to a switching tube, the operating current of the inverter is collected, and a current interval where the operating current is located, namely a target current interval, is determined; and determining a target resistance value matched with the target current interval, and controlling the switching-on resistance of the switching tube to be the target resistance value. Wherein, the target resistance value is in a negative correlation relation with the current value of the current interval. Therefore, in the current conversion state of the power diode to the switching tube, as the current value of the inverter is gradually reduced, the on-resistance of the switching tube is gradually increased, so that the on-speed of the switching tube is reduced, that is, the current conversion speed is reduced, the current change rate of the power diode during current conversion is reduced, and finally the reverse stress at two ends of the power diode is reduced. And when the current of the inverter is larger, the resistance value of the on-resistance of the switching tube is smaller, and the turn-on loss of the switching tube and the turn-off loss of the power diode are reduced, so that the high operation efficiency of the inverter is ensured.
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 introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 shows a topology of a two-level Boost inverter;
fig. 2 shows a circuit diagram of a switching tube driving circuit of an inverter according to an embodiment of the present application;
fig. 3 is a circuit diagram of a driving circuit of another switching tube according to an embodiment of the present application;
FIG. 4 is a schematic diagram illustrating an operation state of the driving circuit shown in FIG. 3;
FIG. 5 is a schematic diagram illustrating another operating state of the driving circuit shown in FIG. 3;
FIG. 6 is a schematic diagram illustrating a further operating state of the driving circuit shown in FIG. 3;
fig. 7 is a circuit diagram of a driving circuit of another switching tube according to an embodiment of the present application;
fig. 8 shows a flowchart of an inverter control method provided in an embodiment of the present application.
Detailed Description
Referring to fig. 1, a topology diagram of a two-level Boost inverter is shown, and as shown in fig. 1, a diode D is used for freewheeling, specifically, when a switching transistor T is turned off, the diode D freewheels. When the switch tube T is switched on, the diode D commutates to the switch tube T, and the diode D is switched off. In the process of researching the invention, the following findings are found: in the process of converting the current of the diode into the current of the switching tube, the problem of overlarge current change rate is easily caused in the turn-off process of the diode D due to the short turn-on time of the switching tube T, and meanwhile, the stress of the diode can be superposed on the switching tube T, so that the stress and the loss of the switching tube are increased. Also, when the operating current of the inverter is small, the more severe the stress of the diode exceeds the standard.
Therefore, in order to solve the technical problem that the stress of a diode exceeds the standard in the process that a power diode in an inverter commutates to a switching tube, the application provides an inverter control method, a switching tube driving circuit, an inverter and a controller. And when the power diode is converted to the switching tube, determining a target resistance value matched with the current according to the running current of the inverter, wherein the target resistance value is inversely related to the running current. With the current value of the inverter becoming smaller, the on-resistance of the switching tube gradually increases to reduce the on-speed of the switching tube, that is, the commutation speed, and further reduce the current change rate of the power diode during commutation, and finally reduce the reverse stress at the two ends of the power diode. When the current of the inverter is large, the driving circuit of the switching tube is switched to the switching-on resistance branch with small resistance value, so that the voltage stress of the power diode and the switching tube cannot exceed the standard, meanwhile, the switching-on loss of the switching tube and the switching-off loss of the power diode are reduced, and the operation efficiency of the inverter cannot be reduced.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. 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 invention.
Referring to fig. 2, a circuit diagram of a switching tube driving circuit of an inverter according to an embodiment of the present application is shown, where the present embodiment is described by taking a switching tube requiring commutation as an example, and as shown in fig. 2, the driving circuit includes: the driving control circuit and a resistance branch circuit connected with the control end of the switch tube T1.
The resistance branch comprises M switching-on resistance branches and one switching-off resistance branch, wherein M is a positive integer larger than 1.
The on-drive end of the drive control circuit is connected with the M on-resistance branches, the off-drive end is connected with the off-resistance branches, and the control signal input end is connected with the controller of the inverter.
In one embodiment of the present application, each of the on-resistance branches includes a control switch Ki and a resistor Roni connected in series, and similarly, the off-resistance branch also includes a control switch Koff and a resistor Roff connected in series.
The control switch can adopt devices with controllable switching function, such as a switch tube and a relay. In the embodiment of the application, the on-off state of each control switch is controlled by the controller.
When the switching tube needs to be controlled to be conducted, the corresponding resistance-switching branch is controlled to be conducted; when the switching tube needs to be controlled to be switched off, the switching-off resistance branch is controlled to be switched on. The embodiment of the present application will mainly describe a process of controlling the switching-on of the switching tube in a process of commutating the power diode to the switching tube. Therefore, the turn-off control of the switching tube is not described in detail.
In one embodiment of the present application, N-1 current thresholds are preset, and the N-1 current thresholds form N current intervals. The current value of the N current intervals is inversely related to the resistance value of the on-resistance of the switching tube, in other words, the on-resistance of the switching tube gradually increases as the current value of the inverter gradually decreases.
When the inverter is in a current conversion state from the power diode to the switching tube, collecting the operating current (namely, the inverter current) of the inverter, comparing the operating current with a preset current threshold value, and determining the current interval where the operating current is located, namely, a target current interval; and then, according to the preset relation of the negative correlation between the current value and the on-resistance, determining an on-resistance branch matched with the target current interval, which is called a target on-resistance branch. At this time, the controller generates a corresponding on-resistance switching signal to be sent to the driving control circuit. At the same time, the controller generates a switching control signal (e.g., a PWM signal) for controlling the open pipe to the driving control circuit.
The driving control circuit controls the corresponding switching-on resistance branch circuit to be conducted according to the received switching-on resistance switching signal, and meanwhile, the driving control circuit transmits the received switching control signal to the control end of the switching tube through the conducted switching-on resistance branch circuit so as to control the switching state of the switching tube.
The effect of the switching-on resistance branch circuit is to change the resistance value of the switching-on resistance of the switching tube, namely, when the current intervals of the running current of the inverter are different, the resistance values of the switching-on resistances connected into the driving circuit are different. The resistance value of the switching-on resistor is inversely related to the switching-on speed of the switching tube, namely the switching-on speed is slower when the switching-on resistor is larger, the switching-on speed of the switching tube is the same as the switching-off speed of the power diode, and the switching-off speed of the power diode is in direct proportion to the current change rate of the power diode.
Therefore, when the inverter is in the process that the power diode is converted to the switching tube and the running current of the inverter is small, the switching-on resistance of the switching tube is switched to the switching-on resistance branch with a large resistance value, the turn-off speed of the power diode is reduced, the current change rate of the power diode is further reduced, and the stress of the power diode and the stress of the switching tube are not over standard. Along with the increase of the current value of the inverter, the switching-on resistance of the switching tube is reduced so as to reduce the switching-on loss of the switching tube and the switching-off loss of the power diode, and finally the high operation efficiency of the inverter is ensured.
It should be noted that the resistance of the on-resistance matched with each current interval may be determined according to actual requirements and experimental data, and will not be described in detail here.
In an application scenario, the number M of the open resistance branches is greater than 1, and
indicating rounding up.
In an embodiment of the present application, the number M of the open resistance branches is equal to N, the resistance values of the open resistance branches are different from each other, and each current interval corresponds to one open resistance branch.
In another embodiment of the present application, the resistive branch is turned onNumber of (2)
The open resistance branches corresponding to each current interval comprise independent open resistance branches, or parallel branches obtained by connecting at least two independent open resistance branches in parallel.
For example, if N is 3, M is log2And 2, in this case, only 2 independent open resistance branches need to be arranged, and 3 branches with different resistance values are obtained by combining 2 open resistance branches.
Assuming that the resistance values of the 2 switching-on resistive branches are Ron1 and Ron2 respectively, and Ron1 is not equal to Ron2, the resistance value of the parallel branch obtained by connecting the two switching-on resistive branches in parallel is Ron1// Ron2, and it can be seen that the two switching-on resistive branches can obtain three different resistance values of Ron1, Ron2, (Ron1// Ron 2).
For another example, if N is 7, M is log2And (7+1) ═ 3, under the condition, only 3 independent open resistance branches need to be arranged, namely, 7 branches with different resistance values are obtained by combining the 3 open resistance branches.
Assuming that the resistance values of the 3 switching-on resistance branches are Ron1, Ron2 and Ron3 respectively, and Ron1 ≠ Ron2 ≠ Ron 3; the resistance values obtained by connecting any two branches of the three branches in parallel are respectively (Ron1// Ron2), (Ron1// Ron3) and (Ron2// Ron 3); the three branches are connected in parallel to obtain the resistance value (Ron1// Ron2// Ron 3). It can be seen that the three open resistive branches can obtain seven different resistances, Ron1, Ron2, Ron3, (Ron1// Ron2), (Ron1// Ron3), (Ron2// Ron3), and (Ron1// Ron2// Ron 3).
By analogy, the number of the resistor branches which are switched on when N is other values and the corresponding resistance values of different parallel branches can be obtained, and details are not described here. In the switching tube driving circuit of the inverter provided in this embodiment, M open resistance branches are provided in the driving circuit of the switch to be commutated,
wherein, N is the number of current intervals, and N is a positive integer greater than 1. When the inverter switches to the switching tube in the process of the power diode converting to the switching tube, the switching-on resistance branches with different resistance values are controlled to be switched on according to different running currents of the inverter, specifically, as the current value of the inverter gradually decreases, the switching-on resistance of the switching tube gradually increases, so that the switching-on speed of the switching tube is reduced, namely, the current conversion speed is reduced, the current change rate of the power diode during current conversion is further reduced, and finally the reverse stress at two ends of the power diode is reduced. And when the current of the inverter is larger, the resistance value of the on-resistance of the switching tube is smaller, and the switching-on loss of the switching tube and the switching-off loss of the power diode are reduced, so that the high operation efficiency of the inverter is ensured.
The following description will take 2 current intervals and 2 open resistive branches provided in the driving circuit of the switching tube as an example.
Referring to fig. 3, a circuit diagram of another driving circuit of a switching tube according to an embodiment of the present application is shown, the driving circuit is used for driving a switching state of a switching tube T1, and as shown in fig. 3, the driving circuit includes: the circuit comprises a drive control circuit, two on resistance branches and one off resistance branch.
As shown in fig. 3, the first open resistance branch comprises a control switch K1 and a resistor Ron1 connected in series; the second, firing, resistive branch comprises control switch K2 and resistor Ron2 in series. The off-resistance branch comprises K3 and a resistance Roff in series.
The first on resistance branch is connected with the first on driving end of the driving control circuit through a first isolation circuit, the second on resistance branch is connected with the second on driving end through a second isolation circuit, and the off resistance branch is connected with the off driving end through a third isolation circuit.
The first, second and third isolation circuits may adopt an optical coupling isolation circuit, a capacitance isolation circuit or a magnetic isolation circuit.
If the driving current output by the isolation circuit is not enough to drive the switching tube at the later stage, a booster circuit is additionally arranged between the isolation circuit and the opening resistance branch circuit to increase the driving capability, such as a push-pull circuit.
The process of the driving circuit controlling the switching tube to be turned on will be described in detail as follows:
in the process that a power diode in the inverter commutates to a switching tube, a controller in the inverter acquires the running current I of the inverter and sets a current threshold value Ith in advance.
In one application scenario, Ron1 > Ron 2. And when I is less than Ith (current threshold), controlling the first switching-on resistance branch to be conducted. In this operating state, Ron1 is turned on when the switch tube is turned on, and Roff is turned off, that is, the switch state of the switch tube is controlled by controlling K1 and K3 to be turned on alternately, wherein the corresponding paths are as shown in fig. 4.
When I is larger than or equal to Ith, the second on-resistance branch is controlled to be conducted, the on-resistance is Ron2, and the off-resistance is Roff, in this case, as shown in FIG. 5, K2 and K3 alternately conduct and control the switch state of the switch tube.
In another application scenario, no matter how large or small the Ron1 and Ron2 are, when I < Ith, the first switching-on resistive branch or the second switching-on resistive branch is controlled to be on, that is, when the switch tube is switched on, Ron1 or Ron2 is applied.
When I is larger than or equal to Ith, the first switching-on circuit branch and the second switching-on circuit branch are controlled to be conducted, under the condition, the resistance value of the input resistor when the switch tube is switched on is Ron1// Ron2, under the condition, K1 and K2 are conducted with K3 in turn, and corresponding paths are shown in figure 6.
Since (Ron1// Ron2) < Ron1 (or Ron2), the size relationship between Ron1 and Ron2 is not required for the application scenario.
It should be noted that the current thresholds Ith, Ron1, Ron2 may be determined according to the parameters of the circuit in practical application.
In the driving circuit of the switching tube provided in this embodiment, two switching-on resistance branches are provided in the driving circuit of the switch that needs commutation, and in the process of commutating the power diode to the switching tube, if the operating current of the inverter is smaller than the current threshold (Ith), the switching-on resistance branch of the large resistance, that is, the first switching-on resistance branch, is switched over; and if the operating current is greater than or equal to Ith, switching to a small-resistance switching-on resistance branch, namely a second switching-on resistance branch (or a parallel branch of the first switching-on resistance branch and the second switching-on resistance branch). When the operating current is small, the high on-resistance is adopted, the conduction speed of the switch tube is reduced, namely the commutation speed is reduced, the current change rate of the power diode during commutation is further reduced, and finally the reverse stress at two ends of the power diode is reduced. And when the current of the inverter is larger, the resistance value of the on-resistance of the switching tube is smaller, and the turn-on loss of the switching tube and the turn-off loss of the power diode are reduced, so that the high operation efficiency of the inverter is ensured.
In another embodiment of the present application, the driving circuit shown in fig. 3 (Ron1 > Ron2) can also be applied to an application scenario in which 2 current thresholds (Ith1 and Ith2, and Ith1 < Ith2) are preset, i.e. including three current intervals,
when the operating current I of the inverter is less than Ith1, that is, the operating current is in a first current interval Iarea1, the first switching-on resistance branch is controlled to be conducted, that is, the Ron1 is put into use when the switching tube is switched on.
When the Ith1 is more than or equal to I and less than Ith2, the running current is in a second current interval Iarea2, and under the condition, the second switching-on resistance branch is controlled to be conducted, namely, the Ron2 is switched on when the switch tube is switched on.
When Ith2 is less than or equal to I, the operating current is in a third current interval Iarea3, under such a condition, the first switching-on resistance branch and the second switching-on resistance branch are controlled to be conducted, that is, the switching-on resistance of the switching tube is the parallel resistance of Ron1 and Ron 2.
By using the driving circuit provided by the embodiment, a plurality of different on-resistances are realized by using the least on-resistance branches, and the number of hardware devices is reduced on the premise of reducing the stress of the power diode and the switch tube and ensuring the operation efficiency of the inverter, so that the hardware cost of the driving control circuit is reduced.
In another application scenario of the present application, the number M of the switching-on resistor branches in the switching tube driving circuit that needs commutation is 1, and the resistance of the switching-on resistor branches can be adjusted.
Referring to fig. 7, a circuit diagram of another switching tube driving circuit of an inverter according to an embodiment of the present disclosure is shown, in which each switching tube driving circuit requiring commutation is provided with a switching-on resistor branch.
As shown in fig. 7, the switching-on resistor branch includes M resistors Ron 1-RonM and a control switch K0 (i.e., a second control switch) connected in series, each resistor has a different resistance value, and each resistor is connected in parallel with one control switch K1-KM (i.e., a first control switch).
Wherein, the first and the second end of the pipe are connected with each other,
which represents rounding up, and N is the number of current intervals. N different resistance values are obtained through the series combination of part or all of the M resistors.
Adjusting the resistance accessed to the open resistance branch by controlling the switching state of K1-KM, wherein Ki is connected with resistance Roni in parallel, when Ki is closed, Roni is short-circuited, namely Ki is closed, and Roni is not accessed to the open resistance branch; when Ki is disconnected, Roni switches into the open resistive branch.
The control switch K0 is used for controlling whether the whole switch-on resistance branch circuit is conducted or not, when K0 is closed, the switch-on resistance branch circuit is conducted, K0 is disconnected, and the switch-on resistance branch circuit is disconnected.
For example, the number N of current segments is 2, and the number M of resistors included in the opened resistor branch is at least 2, i.e., R1 and R2.
If the operating current I of the inverter is less than Ith (current threshold), namely the operating current I is in a first current interval, K1 and K2 are controlled to be disconnected, and at the moment, R1 and R2 are both connected to open the resistance branch.
If the operating current I of the inverter is larger than or equal to Ith, namely the operating current I is in a second current interval, the control unit K1 or K2 is switched off, if K1 is switched off, R1 is connected into the open resistance branch, and if K2 is switched off, R2 is connected into the open resistance branch.
In another embodiment of the present application, the switching-on resistor branch may be provided with a resistance adjustable resistor, such as a potentiometer, which adjusts the resistance of the adjustable resistor to a target resistance according to a current interval in which the operating current of the inverter is located.
In the switching tube driving circuit of the inverter provided by this embodiment, a switching-on resistance branch is arranged in a driving circuit of a switch to be commutated, and when the inverter commutates a power diode to a switching tube, a resistance value of the switching-on resistance branch is adjusted according to different operating currents of the inverter, so that the switching tube is switched on with different switching-on resistances at different operating currents. Specifically, as the current value of the inverter is gradually decreased, the on-resistance of the switching tube is gradually increased, so that the on-speed of the switching tube is reduced, that is, the commutation speed is reduced, the current change rate of the power diode during commutation is reduced, and finally the reverse stress at two ends of the power diode is reduced. And when the current of the inverter is larger, the resistance value of the on-resistance of the switching tube is smaller, and the turn-on loss of the switching tube and the turn-off loss of the power diode are reduced, so that the high operation efficiency of the inverter is ensured.
Corresponding to the embodiment of the switching tube driving circuit, the application also provides an embodiment of a control method of the inverter.
Referring to fig. 8, a flowchart of a control method of an inverter according to an embodiment of the present application is shown, where the method is applied to the above-mentioned switching tube driving circuit to turn on the switching tubes of the inverter with the switching resistors having different resistance values at different operating currents.
As shown in fig. 8, the method may include the steps of:
and S110, when the inverter is in a commutation state that the power diode commutates to the switching tube, acquiring the current of the inverter.
And S120, comparing the inverter current with at least one current threshold value, and determining a target current interval where the inverter current is located.
And S130, determining a target resistance value matched with the target current interval, and controlling the on-resistance of the switching tube to be the target resistance value.
Wherein, the target resistance value is inversely related to the current value of the target current interval.
In an embodiment of the present application, 1 current threshold is set, that is, the current threshold is divided into 2 current intervals, and the number of the opened resistance branches is 2, in this case, the control process of opening the resistance branches is the same as the control process of the embodiment shown in fig. 3, and details are not repeated here.
In the inverter control method provided by this embodiment, at least two open resistance branches are arranged in a driving circuit of a switch to be commutated, and when the inverter commutates a power diode to a switching tube, the switching tube is controlled to be turned on by the open resistances with different resistances according to different operating currents of the inverter. And when the current of the inverter is larger, the resistance value of the on-resistance of the switching tube is smaller, and the turn-on loss of the switching tube and the turn-off loss of the power diode are reduced, so that the high operation efficiency of the inverter is ensured.
On the other hand, the embodiment of the application also provides a controller applied to the inverter, and the controller comprises a memory and a processor; wherein the memory has stored therein program instructions; the processor calls the program instructions in the memory to execute the control process of the switching tube driving circuit.
In another aspect, an embodiment of the present application further provides an inverter, including: the inverter main body circuit, the switching tube driving control circuit provided by the embodiment and the controller are provided.
While, for purposes of simplicity of explanation, the foregoing method embodiments have been described as a series of acts or combination of acts, it will be appreciated by those skilled in the art that the present invention is not limited by the illustrated ordering of acts, as some steps may occur in other orders or concurrently with other steps in accordance with the invention. Further, those skilled in the art should also appreciate that the embodiments described in the specification are preferred embodiments and that the acts and modules referred to are not necessarily required by the invention.
It should be noted that technical features described in the embodiments in the present specification may be replaced or combined with each other, each embodiment is mainly described as a difference from the other embodiments, and the same and similar parts between the embodiments may be referred to each other. For the device-like embodiment, since it is basically similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.
The steps in the method of the embodiments of the present application may be sequentially adjusted, combined, and deleted according to actual needs.
The device and the modules and sub-modules in the terminal in the embodiments of the present application can be combined, divided and deleted according to actual needs.
In the several embodiments provided in the present application, it should be understood that the disclosed terminal, apparatus and method may be implemented in other manners. For example, the above-described terminal embodiments are merely illustrative, and for example, the division of a module or a sub-module is only one logical function division, and other division manners may be available in actual implementation, for example, a plurality of sub-modules or modules may be combined or integrated into another module, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or modules, and may be in an electrical, mechanical or other form.
The modules or sub-modules described as separate parts may or may not be physically separate, and parts that are modules or sub-modules may or may not be physical modules or sub-modules, may be located in one place, or may be distributed over a plurality of network modules or sub-modules. Some or all of the modules or sub-modules can be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
In addition, functional modules or sub-modules in the embodiments of the present application may be integrated into one processing module, or each module or sub-module may exist alone physically, or two or more modules or sub-modules are integrated into one module. The integrated modules or sub-modules may be implemented in the form of hardware, or may be implemented in the form of software functional modules or sub-modules.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (14)
1. An inverter control method, characterized by comprising:
when the inverter is in a current conversion state from a power diode to a switching tube, acquiring the current of the inverter;
comparing the inverter current with at least one current threshold value, and determining a target current interval in which the inverter current is positioned;
and determining a target resistance value matched with the target current interval, and controlling the on-resistance of the switching tube to be the target resistance value, wherein the target resistance value is in negative correlation with the current value of the target current interval, and is used for reducing the current change rate of the power diode during commutation in the process that the current of the inverter is gradually reduced, so that the reverse stress at two ends of the power diode is reduced.
2. The method according to claim 1, wherein a switching-on resistor branch with adjustable resistance is arranged in a driving circuit of the switching tube;
the controlling the on resistance of the switch tube to be the target resistance value comprises the following steps:
and adjusting the resistance value of the switching-on resistance branch circuit to be the target resistance value.
3. The method of claim 2, wherein the total number of current intervals is N, the opening resistor branch comprises a second control switch and M resistors connected in series in sequence, and each resistor is connected in parallel with a first control switch,
represents rounding up;
the adjusting the resistance value of the switching-on resistance branch circuit to the target resistance value comprises:
and controlling the second control switch to be closed to open the opening resistance branch, and controlling the switch state of each first control switch so that the sum of the resistance values of all the resistors connected to the opening resistance branch is equal to the target resistance value.
4. Method according to claim 1, characterized in that the switching tube is driven electrically onM switching-on resistance branches with different resistance values are arranged in the current path, the total number of the current intervals is N, wherein N is a positive integer greater than 1, and
represents rounding up;
the controlling the on resistance of the switch tube to be the target resistance value comprises the following steps:
controlling the resistance value to be the target resistance value, and switching on the resistance branch circuit;
the target opening resistance branch is one opening resistance branch or a branch obtained by connecting at least two opening resistance branches in parallel.
5. The method of claim 4, wherein the current interval comprises a first current interval and a second current interval, and a current value of the first current interval is smaller than a current value of the second current interval, the open resistive branches comprise a first open resistive branch and a second open resistive branch, and a resistance value of the first open resistive branch is larger than a resistance value of the second open resistive branch;
the controlling the on resistance of the switch tube to be the target resistance value comprises the following steps:
when the inverter current is in the first current interval, controlling the first switching-on resistance branch circuit to be conducted;
and when the inverter current is in the second current interval, controlling the second switching-on resistance branch circuit to be switched on.
6. The method according to claim 4, wherein the current interval comprises a first current interval and a second current interval, and the current value of the first current interval is smaller than that of the second current interval, and the open resistance branches of the switch tube comprise a first open resistance branch and a second open resistance branch;
the controlling the switching-on resistance of the switching tube to be the target resistance value comprises the following steps:
when the inverter current is in the first current interval, controlling the first switching-on resistance branch or the second switching-on resistance branch to be switched on;
and when the current of the inverter is in the second current interval, controlling the first switching-on resistance branch circuit and the second switching-on resistance branch circuit to be switched on.
7. A switching tube driving circuit in an inverter, comprising: the control circuit is driven, and each switching tube needing current conversion is provided with at least one switching-on resistance branch and one switching-off resistance branch;
the opening driving end of the driving control circuit is connected with the at least one opening resistance branch circuit;
the turn-off driving end of the driving control circuit is connected with the turn-off resistance branch;
the control signal input end of the drive control circuit is connected with the controller of the inverter, and after the drive control circuit receives a switching-on resistance switching signal sent by the controller, the state of the at least one switching-on resistance branch circuit is controlled, so that the switching-on resistance of the switching tube is equal to a target resistance value;
the switching signal of the switching resistor is determined by the controller according to the inverter current when the inverter is in a current conversion state from the power diode to the switching tube and the current interval where the inverter current is located, and the current value of the current interval is inversely related to the target resistance value, so that the current change rate of the power diode during current conversion is reduced in the process that the inverter current gradually decreases, and the reverse stress at two ends of the power diode is further reduced.
8. The switching tube driving circuit according to claim 7, wherein the total number of the current intervals is N, where N is a positive integer greater than 1;
each switching tube needing current conversion is provided with a switching-on resistance branch, and the resistance value of the switching-on resistance branch is adjustable.
9. The switch tube driving circuit according to claim 8, wherein the switching-on resistor branch comprises a second control switch and M resistors connected in series in turn, each of the M resistors being connected in parallel with a first control switch,
represents rounding up;
and obtaining N target resistance values matched with the N current intervals by combining at least one resistor in the M resistors.
10. The switching tube driving circuit according to claim 7, wherein the total number of the current sections is N, the number of the open resistance branches is M, N is a positive integer greater than 1, and
represents rounding up;
when the M is equal to N, the resistance value of each switching-on resistance branch is respectively matched with the N current intervals;
and when M is less than N, combining at least one of the M switching-on current branches to obtain N resistance values respectively matched with the N current intervals.
11. The switching tube driving circuit according to claim 10, wherein the switching tube switching resistor branch comprises: the circuit comprises a first switching resistor branch and a second switching resistor branch, wherein the resistance value of the first switching resistor branch is larger than that of the second switching resistor branch;
when the drive control circuit receives a first switching signal, the first switching resistance branch circuit is controlled to be conducted, and when the drive control circuit receives a second switching signal, the second switching resistance branch circuit is controlled to be conducted;
the first switching-on resistance switching signal is generated when the controller determines that the inverter current is in a first current interval smaller than a first preset current threshold, and the second switching-on resistance switching signal is generated when the controller determines that the inverter current is in a second current interval larger than or equal to the first preset current threshold.
12. The switching tube driving circuit according to claim 10, wherein the switching tube switching resistor branch comprises: a first open resistance branch and a second open resistance branch;
when the drive control circuit receives a first switching-on resistance switching signal, controlling the first switching-on resistance branch or the second switching-on resistance branch to be switched on; when the drive control circuit receives a second switching-on resistance switching signal, controlling the first switching-on resistance branch circuit and the second switching-on resistance branch circuit to be conducted;
the first switching-on resistance switching signal is generated when the controller determines that the inverter current is in a first current interval smaller than a first preset current threshold, and the second switching-on resistance switching signal is generated when the controller determines that the inverter current is in a second current interval larger than or equal to the first preset current threshold.
13. A controller, comprising: a memory and a processor;
the memory has stored therein program instructions;
the processor invokes program instructions in the memory to perform the inverter control method of any of claims 1-6.
14. An inverter, comprising: an inverter main circuit, a switching tube driving circuit according to any one of claims 7 to 12, and a controller according to claim 13.
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| CN116470736A (en) * | 2022-01-12 | 2023-07-21 | 中兴通讯股份有限公司 | Adjustable driving unit, driving assembly, power conversion device and output control method |
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