The scheme is a divisional application taking an invention patent with a filing date of 2019, 04 month and 01, a filing number of 201910255894.1 and a name of a single-bidirectional switch circuit and a control method thereof as a main application.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: a unidirectional and bidirectional switch circuit and a control method thereof are provided.
In order to solve the technical problems, the first technical scheme adopted by the invention is as follows:
the single-direction and double-direction switching circuit comprises a driving circuit, a diode, a lithium battery, a generator and a switching tube circuit, wherein the switching tube circuit comprises more than two transistors, and more than two transistors are connected in parallel;
the positive pole of the lithium battery is electrically connected with the anode of the diode and the drain electrodes of the more than two transistors which are mutually connected in parallel, the negative pole of the lithium battery is electrically connected with the negative pole of the generator, the negative pole of the diode is electrically connected with the driving circuit, the positive pole of the generator and the source electrodes of the more than two transistors which are mutually connected in parallel, the grid electrodes of the more than two transistors which are mutually connected in parallel are electrically connected with the driving circuit, and the driving circuit is electrically connected with a peripheral control signal.
The second technical scheme adopted by the invention is as follows:
a control method of a unidirectional and bidirectional switching circuit, comprising the steps of:
s1, collecting a loop current value of a lithium battery and receiving a control signal;
s2, judging whether the loop current value of the lithium battery acquired in the step S1 is positive or not;
s3, if not, judging the type of the received control signal;
if the received control signal is a unidirectional signal, all transistors of the switching tube circuit are turned off;
if the received control signal is a bidirectional signal, all transistors of the switching transistor circuit are turned on.
The invention has the beneficial effects that:
by arranging the switching circuit, more than two transistors are connected in parallel, so that the reaction time for controlling the direction of the current of the lithium battery loop can be prolonged; the driving circuit is connected with a control signal of the peripheral equipment, so that the loop current direction of the lithium battery can be judged, and the switching circuit can work in a double control mode. When the external control signal is a bidirectional signal, the single bidirectional switch circuit designed by the scheme also has the overcurrent protection function of the loop reverse current of the lithium battery; the current can be reliably switched, the switching can be controlled at different current points, and the control mode is optimized, for example: and the DSP controls the charging current to switch under the low-temperature state of the lithium battery, and the charging current can be controlled to charge under different temperatures after the temperature of the lithium battery rises.
Detailed Description
In order to describe the technical contents, the achieved objects and effects of the present invention in detail, the following description will be made with reference to the embodiments in conjunction with the accompanying drawings.
The most critical concept of the invention is as follows: the lithium battery charging and discharging protection problem is solved through the cooperation among the driving circuit, the diode, the lithium battery, the generator and the switching tube circuit.
Referring to fig. 1 to 3, the present invention provides a technical solution:
the single-direction and double-direction switching circuit comprises a driving circuit, a diode, a lithium battery, a generator and a switching tube circuit, wherein the switching tube circuit comprises more than two transistors, and more than two transistors are connected in parallel;
the positive pole of the lithium battery is electrically connected with the anode of the diode and the drain electrodes of the more than two transistors which are mutually connected in parallel, the negative pole of the lithium battery is electrically connected with the negative pole of the generator, the negative pole of the diode is electrically connected with the driving circuit, the positive pole of the generator and the source electrodes of the more than two transistors which are mutually connected in parallel, the grid electrodes of the more than two transistors which are mutually connected in parallel are electrically connected with the driving circuit, and the driving circuit is electrically connected with a peripheral control signal.
From the above description, the beneficial effects of the invention are as follows:
by arranging the switching circuit, more than two transistors are connected in parallel, so that the reaction time for controlling the direction of the current of the lithium battery loop can be prolonged; the driving circuit is connected with a control signal of the peripheral equipment, so that the loop current direction of the lithium battery can be judged, and the switching circuit can work in a double control mode. When the external control signal is a bidirectional signal, the single bidirectional switch circuit designed by the scheme also has the overcurrent protection function of the loop reverse current of the lithium battery; the current can be reliably switched, the switching can be controlled at different current points, and the control mode is optimized, for example: and the DSP controls the charging current to switch under the low-temperature state of the lithium battery, and the charging current can be controlled to charge under different temperatures after the temperature of the lithium battery rises.
Further, the device also comprises a tube voltage drop sampling circuit which is respectively and electrically connected with the anode of the diode, the cathode of the diode and the driving circuit.
As can be seen from the above description, the tube voltage drop sampling protection circuit is simple, low in cost and high in response speed, and the loudness of the tube voltage drop sampling protection circuit can reach the level of 100 ns.
Further, the control signal is a unidirectional signal or a bidirectional signal.
As can be seen from the above description, when the control signal is a unidirectional signal, that is, the current can only flow in a positive direction and cannot flow in a reverse direction, the loop current of the lithium battery flows from 0 to positive direction or from negative direction to positive direction, and the delay time can be set to prevent the switching tube circuit from oscillating; when the control signal is a bidirectional signal, the switching tube circuit is always in an on state, and the loop current of the lithium battery can flow in the forward direction or the reverse direction.
Further, the number of the transistors is 2-6.
Further, the transistor is a MOS transistor or an IGBT transistor.
As can be seen from the above description, MOS transistors are currently used in low voltage range, for example: the internal resistance of 100V can be 1 milliohm, the current is 10W after 100A, and a plurality of MOS are connected in parallel to realize the low-power-consumption and high-efficiency electronic switch. IGBT is used for high voltage (300V-1000V) principle similar to MOS, and collector voltage V in the prior artCE And the electronic switch can also achieve about 1.5V, and is an efficient electronic switch (the working frequency is more than 5 KHz).
Referring to fig. 4, another technical solution provided by the present invention is as follows:
a control method of a unidirectional and bidirectional switching circuit, comprising the steps of:
s1, collecting a loop current value of a lithium battery and receiving a control signal;
s2, judging whether the loop current value of the lithium battery acquired in the step S1 is positive or not;
s3, if not, judging the type of the received control signal;
if the received control signal is a unidirectional signal, all transistors of the switching tube circuit are turned off;
if the received control signal is a bidirectional signal, all transistors of the switching transistor circuit are turned on.
Further, step S3 further includes:
if so, all transistors of the switching transistor circuit are turned on.
Further, the method further comprises the following steps:
presetting a first limiting value and a second limiting value, wherein the first limiting value is smaller than the second limiting value, and the first limiting value and the second limiting value are negative numbers;
when the received control signal is a bidirectional signal and the loop current value of the lithium battery is a negative number, comparing the loop current value of the lithium battery with the first current limiting value and the second current limiting value respectively;
if the loop current value is larger than the first current limit value and smaller than the second current limit value, all transistors of the switching tube circuit are turned off;
and if the loop current value is larger than the second current limiting value, all transistors of the switching tube circuit are turned on.
From the above description, when the switching circuit works in the bidirectional signal mode, the negative current of the loop of the lithium battery can be protected to prevent the overcurrent condition; the first current limiting value and the second current limiting value are mainly used for protecting the transistor from reliably working, cannot enter a high-frequency oscillation state, and are matched with the delay switch in time to reliably switch on and off the electronic switch.
Referring to fig. 1 and 3, a first embodiment of the present invention is as follows:
a single-and-double-direction switch circuit, comprising a drive circuit 1, a diode D1, a lithium battery 2, a generator 3 and a switch tube circuit 4, wherein the switch tube circuit 4 comprises more than two transistors, and more than two transistors are connected in parallel;
the positive electrode of the lithium battery 2 is electrically connected with the anode of the diode D1 and the drain electrodes of the more than two transistors which are mutually connected in parallel, the negative electrode of the lithium battery 2 is electrically connected with the negative electrode of the generator 3, the negative electrode of the diode is electrically connected with the driving circuit 1, the positive electrode of the generator 3 and the source electrodes of the more than two transistors which are mutually connected in parallel, the grid electrodes of the more than two transistors which are mutually connected in parallel are electrically connected with the driving circuit 1, and the driving circuit 1 is electrically connected with a peripheral control signal.
The driving circuit 1 comprises a first triode, a second triode and an integrated chip, wherein an emitting electrode of the first triode is electrically connected with an emitting electrode of the second triode, and the integrated chip is respectively electrically connected with a collecting electrode of the first triode and a collecting electrode of the first triode.
Referring to fig. 2 and 3, a second embodiment of the present invention is as follows:
the second embodiment differs from the first embodiment in that: the device also comprises a tube voltage drop sampling circuit 5, wherein the tube voltage drop sampling circuit 5 is respectively and electrically connected with the anode of the diode, the cathode of the diode and the driving circuit 1.
The control signal is a unidirectional signal or a bidirectional signal.
The number of transistors is 2-6, preferably 4.
The transistor is a MOS transistor or an IGBT transistor.
The tube voltage drop sampling circuit 5 comprises an amplifying comparator and an electronic switch, wherein the amplifying comparator is electrically connected with the electronic switch.
Referring to fig. 4, a third embodiment of the present invention is as follows:
a control method of a unidirectional and bidirectional switching circuit, comprising the steps of:
s1, collecting a loop current value of a lithium battery and receiving a control signal; specifically, a loop current value of the lithium battery 2 is collected, and a control signal, namely a unidirectional signal or a bidirectional signal, is received;
s2, judging whether the loop current value of the lithium battery 2 acquired in the step S1 is positive;
s3, if not, judging the type of the received control signal; specifically, if the acquired loop current value of the lithium battery 2 is not positive, judging the type of the received control signal;
if the received control signal is a unidirectional signal, all transistors of the switching tube circuit 4 are turned off;
if the received control signal is a bi-directional signal, all transistors of the switching transistor circuit 4 are turned on.
If so, all transistors of the switching transistor circuit 4 are on.
When the reception control signal is a unidirectional signal and the loop current value of the lithium battery 2 is a negative number, a delay time may be set, which may be adjusted in about 10-100 ms.
Presetting a first limiting value and a second limiting value, wherein the first limiting value is smaller than the second limiting value, and the first limiting value and the second limiting value are negative numbers;
when the received control signal is a bidirectional signal and the loop current value of the lithium battery 2 is a negative number, comparing the loop current value of the lithium battery 2 with the first current limit value and the second current limit value respectively;
if the loop current value is greater than the first current limit value and less than the second current limit value, all transistors of the switching tube circuit 4 are turned off;
if the loop current value is greater than the second current limit value, all transistors of the switching transistor circuit 4 are turned on.
The loop current value can be set as X, the first current limiting value is-3A, and the second current limiting value is-1A;
if-3<X < -1, all transistors of the switching tube circuit are closed;
if X > -1, all transistors of the switching transistor circuit are on.
In summary, according to the single-direction and double-direction switch circuit and the control method thereof provided by the invention, more than two transistors are connected in parallel by arranging the switch circuit, so that the reaction time for controlling the direction of the loop current of the lithium battery can be improved; the driving circuit is connected with a control signal of the peripheral equipment, so that the loop current direction of the lithium battery can be judged, and the switching circuit can work in a double control mode. When the external control signal is a bidirectional signal, the single bidirectional switch circuit designed by the scheme also has the overcurrent protection function of the loop reverse current of the lithium battery; the current can be reliably switched, the switching can be controlled at different current points, and the control mode is optimized, for example: and the DSP controls the charging current to switch under the low-temperature state of the lithium battery, and the charging current can be controlled to charge under different temperatures after the temperature of the lithium battery rises.
The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent changes made by the specification and drawings of the present invention, or direct or indirect application in the relevant art, are included in the scope of the present invention.