Automotive DC / DC converters

Abstract

An on-board DC / DC converter includes: a main transformer including a primary winding and a secondary winding; a first circuit, one end of which is connected to the primary winding and the other end of which is connected to the bus capacitor of the on-board charging system and the high-voltage battery; a second circuit, one end of which is connected to the secondary winding; a third circuit, one end of which is connected to the other end of the second circuit and the other end of which is connected to the low-voltage battery of the on-board charging system; and a fourth circuit, which controls a main charging circuit consisting of the main transformer, the first circuit, the second circuit, and the third circuit. The main charging circuit is capable of forward charging from the high-voltage battery to the low-voltage battery and reverse charging from the low-voltage battery to the bus capacitor. The fourth circuit controls the main charging circuit through an interlock selection circuit to switch between reverse and forward charging. This improves the safety of the on-board charging device.

Description

Technical Field

[0001] The present application relates to the field of vehicle-mounted charging technology, and in particular to a vehicle-mounted DC / DC converter. Background Art

[0002] During the charging process of an on-board charger, if the charging voltage is too high, the charging current will be very large, which may damage the busbar and capacitor. Therefore, in the prior art, in order to limit the charging current, a pre-charging process is usually added to the on-board charger to achieve the purpose of protecting the circuit.

[0003] Because the busbars of the on-board charger (OBC) contain large-capacity electrolytic capacitors for voltage stabilization, a traditional pre-charging circuit typically pre-charges the busbar capacitors before the OBC is started to suppress input pulse current. This circuit consists of a relay and a resistor. Alternatively, a pre-charging circuit is added to the busbar on the high-voltage battery side to prevent inrush current.

[0004] However, although the additional pre-charging circuit ensures circuit safety, it also causes problems such as a larger size and higher cost of the on-board charger.

[0005] In the prior art, for example, Chinese patent CN112421961A provides an on-board charging device with a reverse pre-charging circuit function that integrates forward charging and reverse charging modes. However, the on-board charging device provided by this patent still has the following problems: the selection of forward charging and reverse pre-charging is prone to errors, and there are problems with measuring and controlling circuits such as the low-voltage battery side and the high-voltage battery side, further affecting the safety of the charging device. Summary of the Invention

[0006] The technical problems to be solved by the present invention are: how to further avoid circuit selection errors, and how to collect the electrical properties of the electrical device to control the charging device and improve the safety of the charging device.

[0007] In order to solve the above technical problems, the present invention provides a vehicle-mounted DC / DC converter, the purpose of which is to improve the automatic measurement and control charging performance of the charging device and enhance safety.

[0008] In order to achieve the above object, the present invention provides a vehicle-mounted DC / DC converter, comprising:

[0009] Main transformer, including primary winding and secondary winding;

[0010] a first circuit, one end of the first circuit being connected to the primary winding, and the other end of the first circuit being connected to a bus capacitor and a high-voltage battery of an on-board charging system;

[0011] a second circuit, one end of the second circuit being connected to the secondary winding;

[0012] a third circuit, one end of the third circuit being connected to the other end of the second circuit, and the other end of the third circuit being connected to a low-voltage battery of an on-board charging system;

[0013] The fourth circuit controls the main charging circuit composed of the main transformer, the first circuit, the second circuit, and the third circuit. The main charging circuit can realize forward charging from the high-voltage battery to the low-voltage battery and reverse charging from the low-voltage battery to the bus capacitor. The fourth circuit controls the main charging circuit through the interlock selection circuit it contains to realize switching between reverse charging and forward charging.

[0014] Preferably, the first circuit includes:

[0015] a first primary switching tube, one end of which is connected to the first end of the primary winding of the main transformer, and the other end of which is connected to the positive electrode of the high-voltage battery; a second primary switching tube, one end of which is connected to the first end of the primary winding of the main transformer, and the other end of which is connected to the negative electrode of the high-voltage battery; a first primary capacitor, one end of which is connected to the positive electrode of the high-voltage battery, and the other end of which is connected to the second end of the primary winding of the main transformer; a second primary capacitor, one end of which is connected to the negative electrode of the high-voltage battery, and the other end of which is connected to the second end of the primary winding of the main transformer; or

[0016] a first primary switching tube, one end of the first primary switching tube is connected to the first end of the primary winding of the main transformer, and the other end of the first primary switching tube is connected to the positive electrode of the high-voltage battery; a second primary switching tube, one end of the second primary switching tube is connected to the first end of the primary winding of the main transformer, and the other end of the second primary switching tube is connected to the negative electrode of the high-voltage battery; a third primary switching tube, one end of the third primary switching tube is connected to the positive electrode of the high-voltage battery, and the other end of the third primary switching tube is connected to the second end of the primary winding of the main transformer; a fourth primary switching tube, one end of the fourth primary switching tube is connected to the negative electrode of the high-voltage battery, and the other end of the fourth primary switching tube is connected to the second end of the primary winding of the main transformer.

[0017] Preferably, the second circuit includes:

[0018] a first secondary inductor, one end of the first secondary inductor is connected to the positive electrode of one end of the third circuit, and the other end of the first secondary inductor is connected to the second end of the secondary winding of the main transformer; a second secondary inductor, one end of the second secondary inductor is connected to the positive electrode of one end of the third circuit, and the other end of the second secondary inductor is connected to the first end of the secondary winding of the main transformer; a first secondary switch tube, one end of the first secondary switch tube is connected to the second end of the secondary winding, and the other end of the first secondary switch tube is connected to the negative electrode of the low-voltage battery; a second secondary switch tube, one end of the second secondary switch tube is connected to the first end of the secondary winding of the main transformer, and the other end of the second secondary switch tube is connected to the negative electrode of the low-voltage battery; or

[0019] a fourth secondary inductor, one end of the fourth secondary inductor being connected to the positive electrode of one end of the third circuit; a third secondary switch tube, one end of the third secondary switch tube being connected to the other end of the fourth secondary inductor, and the other end of the third secondary switch tube being connected to the first end of the secondary winding of the main transformer; and a fourth secondary switch tube, one end of the fourth secondary switch tube being connected to the other end of the fourth secondary inductor, and the other end of the fourth secondary switch tube being connected to the second end of the secondary winding of the main transformer.

[0020] Preferably, the third circuit includes:

[0021] A filter capacitor, the filter capacitor is connected in parallel with the second circuit; a filter inductor, one end of the filter inductor is connected to the first end of the filter capacitor; a first anti-backflow switch tube and a second anti-reverse polarity switch tube, one end of the first anti-backflow switch tube is connected to the other end of the filter inductor, the other end of the first anti-backflow switch tube is connected to one end of the second anti-reverse polarity switch tube, the negative pole of the parasitic diode of the first anti-backflow switch tube is connected to the negative pole of the parasitic diode of the second anti-reverse polarity switch tube, the other end of the second anti-reverse polarity switch tube is connected to the positive pole of the low-voltage battery, and the fourth circuit output control connects the first anti-backflow switch tube and the second anti-reverse polarity switch tube; a freewheeling diode, the first end of the freewheeling diode is connected to the negative pole of the low-voltage battery, and the second end of the freewheeling diode is connected to the connection end of the first anti-backflow switch tube and the filter inductor.

[0022] Preferably, on the basis of the third circuit:

[0023] A circuit in which a freewheeling switch tube and a diode are connected in parallel is used to replace the freewheeling diode, the anode of the diode connected in parallel with the freewheeling switch tube is connected to the negative electrode of the low-voltage battery, and the cathode of the diode connected in parallel with the freewheeling switch tube is connected to the connection end of the first anti-backflow switch tube and the filter inductor; or, a freewheeling switch tube is used to replace the freewheeling diode, the cathode of the diode connected in parallel with the freewheeling switch tube is connected to the negative electrode of the low-voltage battery, and the anode of the diode connected in parallel with the freewheeling switch tube is connected to the connection end of the first anti-backflow switch tube and the filter inductor; or,

[0024] A circuit in which a freewheeling switch tube and a diode are connected in parallel and then in series with a freewheeling diode is used to replace the freewheeling diode, wherein the anode of the diode connected in parallel with the freewheeling switch tube is connected to the negative electrode of the low-voltage battery, the cathode of the diode connected in parallel with the freewheeling switch tube is connected to the anode of the freewheeling diode, and the cathode of the freewheeling diode is connected to the connection terminal of the first anti-backflow switch tube and the filter inductor; or

[0025] A circuit in which a freewheeling switch tube and a diode are connected in parallel and then in series with a freewheeling diode is used to replace the freewheeling diode. The cathode of the diode connected in parallel with the freewheeling switch tube is connected to the negative electrode of the low-voltage battery, the anode of the diode connected in parallel with the freewheeling switch tube is connected to the anode of the freewheeling diode, and the cathode of the freewheeling diode is connected to the connection terminal of the first anti-backflow switch tube and the filter inductor.

[0026] Preferably, on the basis of the third circuit:

[0027] A second switch is used to replace the second anti-reverse connection switch tube, one end of the first anti-backflow switch tube is connected to the other end of the filter inductor, the other end of the first anti-backflow switch tube is connected to one end of the second switch, the negative electrode of the parasitic diode of the first anti-backflow switch tube is connected to one end of the second switch, the other end of the second switch is connected to the positive electrode of the low-voltage battery, and the fourth circuit output control is connected to the first anti-backflow switch tube and the second switch.

[0028] Preferably, the third circuit includes: a first anti-backflow switch tube; a second anti-reverse connection switch tube or a second switch;

[0029] The fourth circuit includes:

[0030] a first microcontroller unit, the first microcontroller unit being connected to a reverse branch circuit for outputting a reverse charging signal to the main charging circuit; one end of the reverse branch circuit being connected to the first microcontroller unit, and the other end of the reverse branch circuit being connected to a first anti-backflow switch tube; and a drive circuit and a reverse control switch being connected in series to the reverse branch circuit;

[0031] a second microcontroller unit, the second microcontroller unit being connected to a forward branch circuit outputting a forward charging signal to the main charging circuit; one end of the forward branch circuit being connected to the second microcontroller unit, and the other end of the forward branch circuit being connected to the first anti-backflow switch tube; and an Oring circuit and a forward control switch being connected in series to the forward branch circuit;

[0032] a third microcontroller unit, wherein the third microcontroller unit sends a signal directly connected to the drive circuit to output a reverse control switch control signal, and sends a signal connected to the inverter and connected to the drive circuit to output a forward control switch control signal, so as to output a reverse control switch control signal and a forward control switch control signal in parallel, the reverse control switch control signal and the forward control switch control signal having opposite output signals; the reverse control switch control signal controls the opening and closing of the reverse control switch; and the forward control switch control signal controls the opening and closing of the forward control switch; or, the reverse control switch control signal and the forward control switch control signal are respectively outputted at two output pins of the data signal processor to control the opening and closing of the forward control switch and the reverse control switch;

[0033] The fourth micro control unit transmits the measurement and control signal to the second anti-reverse connection switch tube or the second switch through the driving circuit.

[0034] Preferably, the first micro control unit, the second micro control unit, the third micro control unit, and the fourth micro control unit are independent micro control units that communicate with each other; or,

[0035] Any two, any three, or four of the first microcontroller unit, the second microcontroller unit, the third microcontroller unit, and the fourth microcontroller unit are integrated into an integrated microcontroller unit, and the internal subunits of the integrated microcontroller unit are communicatively connected, or the integrated microcontroller units are communicatively connected with each other, or the integrated microcontroller unit and a non-integrated microcontroller unit are communicatively connected.

[0036] Preferably, based on the fourth circuit: a fifth microcontroller unit is used to replace the Oring circuit;

[0037] The first micro control unit, the second micro control unit, the third micro control unit, the fourth micro control unit, and the fifth micro control unit are independent micro control units that communicate with each other; or

[0038] Any two, any three, any four or five of the first microcontroller unit, the second microcontroller unit, the third microcontroller unit, the fourth microcontroller unit and the fifth microcontroller unit are integrated into an integrated microcontroller unit, and the internal subunits of the integrated microcontroller unit are communicatively connected, or the integrated microcontroller units are communicatively connected with each other, or the integrated microcontroller unit and a non-integrated microcontroller unit are communicatively connected.

[0039] Preferably, the third circuit further includes a first sensing resistor and a second sensing resistor; one end of the first sensing resistor is connected to one end of the second anti-reverse polarity switch tube or the second switch, the other end of the second anti-reverse polarity switch tube or the second switch is connected to one end of the first anti-backflow switch tube, and the other end of the first anti-backflow switch tube is connected to one end of the second sensing resistor;

[0040] The fourth circuit includes: a sixth microcontroller unit, the sixth microcontroller unit being connected to the other end of the first sensing resistor and the other end of the second sensing resistor to obtain corresponding voltage and current signals for controlling whether to turn on the second anti-reverse polarity switch tube or the second switch and to perform reverse charging and forward charging processes;

[0041] The first micro control unit, the second micro control unit, the third micro control unit, the fourth micro control unit, the fifth micro control unit, and the sixth micro control unit are independent micro control units that communicate with each other; or

[0042] Any two, any three, any four, any five or six of the first microcontroller unit, the second microcontroller unit, the third microcontroller unit, the fourth microcontroller unit, the fifth microcontroller unit and the sixth microcontroller unit are integrated into an integrated microcontroller unit, and the internal subunits of the integrated microcontroller unit are communicatively connected, or the integrated microcontroller units are communicatively connected with each other, or the integrated microcontroller unit and a non-integrated microcontroller unit are communicatively connected.

[0043] Compared to the prior art, the present invention provides an on-vehicle DC / DC converter, comprising: a main transformer including a primary winding and a secondary winding; a first circuit, one end of the first circuit connected to the primary winding, the other end of the first circuit connected to the bus capacitor of the on-vehicle charging system and the high-voltage battery; a second circuit, one end of the second circuit connected to the secondary winding; a third circuit, one end of the third circuit connected to the other end of the second circuit, the other end of the third circuit connected to the low-voltage battery of the on-vehicle charging system; a fourth circuit, the fourth circuit controlling a main charging circuit consisting of the main transformer, the first circuit, the second circuit, and the third circuit, the main charging circuit being capable of forward charging from the high-voltage battery to the low-voltage battery and reverse charging from the low-voltage battery to the bus capacitor; the fourth circuit controlling the main charging circuit via an interlock selection circuit to enable switching between reverse and forward charging. Therefore, compared to the prior art, the present invention can achieve the technical effect of improving the safety of the on-vehicle charging device. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0045] Figure 1 A circuit connection diagram of an embodiment of a vehicle-mounted DC / DC converter provided by the present invention is shown.

[0046] Figure 2 A circuit connection diagram of another embodiment of the vehicle-mounted DC / DC converter provided by the present invention is shown.

[0047] Figure 3 The following is a partial circuit connection diagram of another embodiment of the vehicle-mounted DC / DC converter provided by the present invention, mainly a first circuit connection diagram.

[0048] Figures 4A to 4I A connection diagram of part of the circuits of another embodiment of the vehicle-mounted DC / DC converter provided by the present invention is shown, mainly a connection diagram of the third circuit.

[0049] Figures 5A to 5C A connection diagram of part of the circuits of another embodiment of the vehicle-mounted DC / DC converter provided by the present invention is shown, mainly a connection diagram of the fourth circuit.

[0050] Figures 6A to 6H The circuit diagram of the vehicle-mounted DC / DC converter provided by the present invention is shown.

[0051] Description of reference numerals:

[0052] 110 Second Circuit

[0053] 120 First Circuit

[0054] 130 Main transformer

[0055] 140 low voltage battery

[0056] 150 high voltage battery

[0057] 160 Third Circuit

[0058] 170 Fourth Circuit

[0059] 171 Reverser

[0060] 172 drive circuit

[0061] 173 drive circuit

[0062] 174a ORing circuit

[0063] 174b Fifth micro control unit

[0064] 175 Reverse branch

[0065] 176 Forward branch

[0066] 177 drive circuit

[0067] 178 Microcontroller unit. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0069] It should be understood that the terms "first," "second," and the like in the claims, specification, and drawings of this application are used to distinguish different objects, rather than to describe a specific order. The terms "comprise" and "comprising" used in the specification and claims of this application indicate the presence of the described features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0070] First embodiment.

[0071] Figure 1 A circuit connection diagram of a first embodiment of a vehicle-mounted DC / DC converter provided by the present invention is shown.

[0072] like Figure 1As shown, an embodiment of an on-vehicle DC / DC converter includes: a main transformer 130, a first circuit 120, a second circuit 110, a third circuit 160, and a fourth circuit 170. The main transformer 130 includes a primary winding and a secondary winding. One end of the first circuit 120 is connected to the primary winding, and the other end of the first circuit 120 is connected to the bus capacitor C4 of the on-vehicle charging system and the high-voltage battery 150. One end of the second circuit 110 is connected to the secondary winding. One end of the third circuit 160 is connected to the other end of the second circuit 110, and the other end of the third circuit 160 is connected to the low-voltage battery 140 of the on-vehicle charging system. The fourth circuit 170 controls the main charging circuit consisting of the main transformer 130, the first circuit 120, the second circuit 110, and the third circuit 160. The main charging circuit can realize forward charging from the high-voltage battery 150 to the low-voltage battery 140 and reverse charging from the low-voltage battery 140 to the bus capacitor C4. The fourth circuit 170 controls the main charging circuit to switch between reverse charging and forward charging.

[0073] The first circuit 120 includes a first primary switching transistor P1, a second primary switching transistor P2, a first primary capacitor C1, and a second primary capacitor C2. One end of the first primary switching transistor P1 is connected to the first end of the primary winding of the main transformer 130, and the other end of the first primary switching transistor P1 is connected to the positive electrode of the high-voltage battery 150. One end of the second primary switching transistor P2 is connected to the first end of the primary winding of the main transformer 130, and the other end of the second primary switching transistor P2 is connected to the negative electrode of the high-voltage battery 150. One end of the first primary capacitor C1 is connected to the positive electrode of the high-voltage battery 150, and the other end of the first primary capacitor C1 is connected to the second end of the primary winding of the main transformer 130. One end of the second primary capacitor C2 is connected to the negative electrode of the high-voltage battery 150, and the other end of the second primary capacitor C2 is connected to the second end of the primary winding of the main transformer 130.

[0074] The second circuit 110 includes a first secondary inductor L1, a second secondary inductor L2, a first secondary switch SR1, and a second secondary switch SR2. One end of the first secondary inductor L1 is connected to the positive electrode of one end of the third circuit 160, and the other end of the first secondary inductor L1 is connected to the second end of the secondary winding of the main transformer 130. One end of the second secondary inductor L2 is connected to the positive electrode of one end of the third circuit 160, and the other end of the second secondary inductor L2 is connected to the first end of the secondary winding of the main transformer 130. One end of the first secondary switch SR1 is connected to the other end of the first secondary inductor L1, and the other end of the first secondary switch SR1 is connected to the negative electrode of the low-voltage battery 140. One end of the first secondary switch SR1 is connected to the second end of the secondary winding of the main transformer 130. One end of the second secondary switch SR2 is connected to the first end of the secondary winding of the main transformer 130, and the other end of the second secondary switch SR2 is connected to the negative electrode of the low-voltage battery 140.

[0075] The third circuit 160 includes: a filter capacitor C3, a filter inductor L3, a first anti-backflow switch S3, a second anti-reverse polarity switch S4, and a freewheeling diode D3. The filter capacitor C3 is connected in parallel with the second circuit 110. One end of the filter inductor L3 is connected to the first end of the filter capacitor C3. One end of the first anti-backflow switch S3 is connected to the other end of the filter inductor L3, and the other end of the first anti-backflow switch S3 is connected to one end of the second anti-reverse polarity switch S4. The cathode of the parasitic diode of the first anti-backflow switch S3 is connected to the cathode of the parasitic diode of the second anti-reverse polarity switch S4, and the other end of the second anti-reverse polarity switch S4 is connected to the positive electrode of the low-voltage battery 140. The output control of the fourth circuit 170 is connected to the first anti-backflow switch S3 and the second anti-reverse polarity switch S4. The anode of the freewheeling diode D3 is connected to the negative electrode of the low-voltage battery 140, and the cathode of the freewheeling diode D3 is connected to the connection between the first anti-backflow switch S3 and the filter inductor L3.

[0076] The fourth circuit 170 includes a micro control unit 178 .

[0077] The microcontroller unit (MCU) 178 is connected to a reverse branch 175 that outputs a reverse charging signal to the main charging circuit. One end of the reverse branch 175 is connected to the microcontroller unit 178, and the other end of the reverse branch 175 is connected to the first anti-backflow switch S3. The reverse branch 175 is connected in series with the drive circuit 173 and the reverse control switch S A The microcontroller unit (MCU) 178 herein may be understood as a first microcontroller unit.

[0078] The microcontroller unit (MCU) 178 is connected to a forward branch 176 that outputs a positive charging signal to the main charging circuit. One end of the forward branch 176 is connected to the microcontroller unit 178, and the other end of the forward branch 176 is connected to the first anti-backflow switch S3. The forward branch 176 is connected in series with an Oring circuit 174a and a forward control switch S C The microcontroller unit (MCU) 178 herein may be understood as a second microcontroller unit.

[0079] The microcontroller unit (MCU) 178 sends a signal directly connected to the drive circuit 172 to output the reverse control switch control signal S A Driver; Microcontroller unit (MCU) 178 sends a signal to connect the inverter 171, connect the drive circuit 172 to output the forward control switch control signal S C Driver, used to parallel output the opposite reverse control switch control signal S A Driver and forward control switch control signal S C Driver. Reverse control switch control signal S ADriver controls the opening and closing of the reverse control switch; the forward control switch controls the signal S C Driver controls the forward control switch S C The microcontroller unit (MCU) 178 herein may be understood as a third microcontroller unit.

[0080] In some embodiments, the reverse control switch control signal S can be outputted from two pins of the digital signal processor (DSP). A Driver and forward control switch control signal S C Driver.

[0081] Of course, the reverse control switch control signal S A Driver and forward control switch control signal S C Driver is also the opposite, that is, reverse control switch control signal S A When Driver is set high, the forward control switch control signal S C Driver is set low; reverse control switch control signal S A When Driver is set low, the forward control switch control signal S C Driver is set high. That is, it can be ensured from multiple control angles that one of the switches S A (or S C ) is closed, the other switch S C (or S A ) is disconnected and non-conductive, so at most only one of the reverse branch 175 and the forward branch 176 is conductive, thereby improving safety against reverse connection. Reverse branch 175 and forward branch 176 are used to output reverse and forward charging control signals, respectively, to the main charging circuit. These reverse and forward charging control signals can control the opening and closing of certain controlled switches in the first, second, and third circuits of the main charging circuit.

[0082] The micro control unit (MCU) 178 transmits the measurement and control signal to the second anti-reverse polarity switch tube S4 or the second switch S4 through the driving circuit 177. The micro control unit (MCU) 178 here can be understood as a fourth micro control unit.

[0083] In other words, the first micro control unit, the second micro control unit, the third micro control unit, and the fourth micro control unit are merely subunits or a control branch of the micro control unit (MCU) 178 .

[0084] The fourth circuit 170 and the third circuit 160 include: a first anti-backflow switch tube S3; a second anti-reverse connection switch tube S4 or a second switch S4, thereby realizing the control of the main charging circuit by the fourth circuit 170.

[0085] Second embodiment.

[0086] Figure 2 A circuit connection diagram of a second embodiment of the vehicle-mounted DC / DC converter provided by the present invention is shown.

[0087] The main difference from the first embodiment lies in the different components and connection methods of the second circuit 110.

[0088] The second circuit 110 includes a fourth secondary inductor L4, a third secondary switch SR3, and a fourth secondary switch SR4. One end of the fourth secondary inductor L4 is connected to the positive electrode of one end of the third circuit 160. The other end of the fourth secondary inductor L4 is connected to one end of the third secondary switch SR3 and one end of the fourth secondary switch SR4. The other end of the third secondary switch SR3 is connected to the first end of the secondary winding of the main transformer 130. The other end of the fourth secondary switch SR4 is connected to the second end of the secondary winding of the main transformer 130. The midpoint of the secondary winding of the main transformer 130 is connected to the negative electrode of the low-voltage battery 140. The other end of the fourth secondary inductor L4 is connected to one end of the third secondary switch SR3.

[0089] Third embodiment.

[0090] Figure 3 The third embodiment of the vehicle-mounted DC / DC converter provided by the present invention is shown in a partial circuit connection diagram. The main difference between the third embodiment and the first and second embodiments is that the components and connection methods of the first circuit 120 are different.

[0091] The first circuit 120 includes a first primary switching transistor P1, a second primary switching transistor P2, a third primary switching transistor P3, and a fourth primary switching transistor P4. One end of the first primary switching transistor P1 is connected to the first end of the primary winding of the main transformer 130, and the other end of the first primary switching transistor P1 is connected to the positive electrode of the high-voltage battery 150. One end of the second primary switching transistor P2 is connected to the first end of the primary winding of the main transformer 130, and the other end of the second primary switching transistor P2 is connected to the negative electrode of the high-voltage battery 150. One end of the third primary switching transistor P3 is connected to the positive electrode of the high-voltage battery 150, and the other end of the third primary switching transistor P3 is connected to the second end of the primary winding of the main transformer 130. One end of the fourth primary switching transistor P4 is connected to the negative electrode of the high-voltage battery 150, and the other end of the fourth primary switching transistor P4 is connected to the second end of the primary winding of the main transformer 130. That is, the main difference from the first embodiment and the second embodiment is that the third primary switch tube P3 replaces the first primary capacitor C1, and the fourth primary switch tube P4 replaces the second primary capacitor C2.

[0092] Fourth embodiment.

[0093] Figures 4A to 4I The diagram shows a partial circuit connection diagram of the fourth embodiment of the vehicle-mounted DC / DC converter provided by the present invention. The main difference between the fourth embodiment and the first, second, and third embodiments lies in the different components and connection methods of the third circuit 160.

[0094] The first case. Figure 4A As shown, on the basis of the third circuit 160 described above (the first embodiment, the second embodiment, and the third embodiment): a freewheeling switch tube S5 is used to replace the freewheeling diode D3, the anode of the diode (such as a parasitic diode) connected in parallel with the freewheeling switch tube S5 is connected to the negative electrode of the low-voltage battery 140, and the cathode of the diode connected in parallel with the freewheeling switch tube S5 is connected to the connection end of the first anti-backflow switch tube S3 and the filter inductor L3.

[0095] The second situation. Figure 4B As shown, on the basis of the third circuit 160 described above (the first embodiment, the second embodiment, and the third embodiment): a freewheeling switch tube S5 is used to replace the freewheeling diode D3, the cathode of the diode (such as a parasitic diode) connected in parallel with the freewheeling switch tube S5 is connected to the negative electrode of the low-voltage battery 140, and the anode of the diode connected in parallel with the freewheeling switch tube S5 is connected to the connection end of the first anti-backflow switch tube S3 and the filter inductor L3.

[0096] The third situation. Figure 4CAs shown, based on the third circuit 160 described above (in the first, second, and third embodiments), a series circuit of a freewheeling switch S5 and a freewheeling diode D3 is used instead of the freewheeling diode D3. The anode of the parasitic diode of the freewheeling switch S5 is connected to the negative electrode of the low-voltage battery 140. The cathode of a diode (e.g., a parasitic diode) connected in parallel with the freewheeling switch S5 is connected to the anode of the freewheeling diode D3. The cathode of the freewheeling diode D3 is connected to the connection between the first anti-backflow switch S3 and the filter inductor L3.

[0097] The fourth situation. Figure 4D As shown, based on the third circuit 160 described above (in the first, second, and third embodiments), a series circuit of a freewheeling switch S5 and a freewheeling diode D3 is used instead of the freewheeling diode D3. The cathode of the diode (e.g., a parasitic diode) connected in parallel with the freewheeling switch S5 is connected to the negative electrode of the low-voltage battery 140, the anode of the diode (e.g., a parasitic diode) connected in parallel with the freewheeling switch S5 is connected to the anode of the freewheeling diode D3, and the cathode of the freewheeling diode D3 is connected to the connection between the first anti-backflow switch S3 and the filter inductor L3.

[0098] The fifth situation. Figure 4E 、 Figure 4F 、 Figure 4G 、 Figure 4H 、 Figure 4I As shown, based on the third circuit 160 described above (the first, second, third, and fourth scenarios of the first, second, third, and fourth embodiments), a second switch S4 is used to replace the second reverse polarity prevention switch S4. One end of the first reverse polarity prevention switch S3 is connected to the other end of the filter inductor L3, the other end of the first reverse polarity prevention switch S3 is connected to one end of the second switch S4, the cathode of the parasitic diode of the first reverse polarity prevention switch S3 is connected to one end of the second switch S4, and the other end of the second switch S4 is connected to the positive electrode of the low-voltage battery 140. The output of the fourth circuit 170 controls the connection between the first reverse polarity prevention switch S3 and the second switch S4. The second switch S4 can use a relay coil to control the opening and closing of its contacts. Figure 4E On the basis of the third circuit 160 of the first embodiment, the second embodiment and the third embodiment, a second switch S4 is used to replace the second anti-reverse connection switch tube S4. Figure 4F In the first case of the fourth embodiment ( Figure 4A On the basis of the third circuit 160 shown in FIG, a second switch S4 is used to replace the second anti-reverse connection switch tube S4. Figure 4G In the second case of the fourth embodiment ( Figure 4B On the basis of the third circuit 160 shown in FIG, a second switch S4 is used to replace the second anti-reverse connection switch tube S4. Figure 4H In the third case of the fourth embodiment ( Figure 4C On the basis of the third circuit 160 shown in FIG, a second switch S4 is used to replace the second anti-reverse connection switch tube S4. Figure 4I In the fourth case of the fourth embodiment ( Figure 4D On the basis of the third circuit 160 shown in FIG, a second switch S4 is used to replace the second anti-reverse connection switch tube S4.

[0099] Fifth embodiment.

[0100] Figures 5A to 5C A partial circuit connection diagram of a fifth embodiment of the vehicle-mounted DC / DC converter provided by the present invention is shown. The main difference between the fifth embodiment and the first, second, third, and fourth embodiments lies in the different components and connection methods of the fourth circuit 170.

[0101] The first case. Figure 5A As shown, the microcontroller unit (MCU) 178 is composed of two microcontroller units, MCU1 and MCU2. It can be understood that the microcontroller unit MCU2 is the first microcontroller unit. The second, third, and fourth microcontroller units are implemented by the microcontroller unit MCU1.

[0102] The second situation. Figure 5B As shown, in Figure 5A On the basis of the fourth circuit 170 shown, a first sensing resistor R is further provided at the third circuit 160. sense1 and the second sensing resistor R sense2 The first sensing resistor R sense1 One end of the second anti-reverse switching tube S4 or one end of the second switch S4 is connected to one end of the first anti-backflow switching tube S3, and the other end of the first anti-backflow switching tube S3 is connected to the second sensing resistor R sense2 The fourth circuit includes: a sixth micro control unit, Figure 5B The sixth micro control unit is connected to the first sensing resistor R sense1 The other end of the second sensing resistor R sense2 The other end is used to obtain corresponding voltage and current signals, which are used to control whether to turn on the second anti-reverse polarity switch tube S4 or the second switch S4 and whether to input signals for reverse charging and forward charging processes on the first anti-backflow switch tube S3.

[0103] The third situation. Figure 5C As shown, in Figure 5BOn the basis of the fourth circuit 170 shown, a fifth micro control unit (MCU3) 174b is used to replace the ORing circuit 174a. The fifth micro control unit (MCU3) 174b can be a part of the micro control unit (MCU) 178.

[0104] It should be understood that the first microcontroller unit, the second microcontroller unit, the third microcontroller unit, the fourth microcontroller unit, the fifth microcontroller unit, and the sixth microcontroller unit are independent microcontroller units that communicate with each other. Alternatively, any two, any three, any four, any five, or any six of the first microcontroller unit, the second microcontroller unit, the third microcontroller unit, the fourth microcontroller unit, the fifth microcontroller unit, and the sixth microcontroller unit may be integrated into an integrated microcontroller unit, and the subunits within the integrated microcontroller unit may be communicatively connected, or the integrated microcontroller units may be communicatively connected with each other, or the integrated microcontroller unit may be communicatively connected with a non-integrated microcontroller unit.

[0105] The switch tube can be a metal oxide semiconductor field effect transistor, or other types of switch tubes. It can also be a switch in the form of a relay control contact. In addition to one end and another end, the switch tube also includes a third end for receiving a switch control signal to control whether the switch tube is turned on or off. For example, the third end can receive a reverse charging signal, a forward charging signal, etc.

[0106] The ORing circuit 174a can also be made into a MOS tube, or can be a gating circuit.

[0107] The above is a description of the structural composition and connection method of the vehicle-mounted DC / DC converter provided by the present invention.

[0108] Taking the first embodiment of the vehicle-mounted DC / DC converter provided by the present invention as an example, the circuit principle provided by the present invention is analyzed.

[0109] like Figure 6A As shown, the first step of the fourth circuit 170 is the circuit principle. First, the main charging circuit is tested, for example, using Figure 5B and Figure 5C The first sensing resistor R sense1 and the second sensing resistor R sense2 . With the first sensing resistor R sense1 and the second sensing resistor R sense2 In this case, the sampling point (the first sensing resistor R sense1 Connect the low voltage battery 140 end, the second sensing resistor R sense2The voltage of the filter inductor L3 is sampled for subsequent judgment. When the low-voltage battery 140 is connected, the self-test starts and the voltage of the low-voltage battery 140 side is sampled. If the voltage of the low-voltage battery 140 side is abnormal or reversely connected, the measurement and control signal S4 Driver is set low, and the reverse control switch control signal S A Driver and forward control switch control signal S C Driver is set to low, the first anti-backflow switch S3 and the second anti-reverse switch S4 are disconnected, and the low-voltage battery 140 is reported to be abnormal. If the low-voltage battery 140 is low, the measurement and control signal S4 Driver is set to high. In addition, the reverse control switch control signal S A Driver is set to high. The second anti-reverse switch S4, the reverse control switch S A Closed, ready for reverse charging (pre-charging).

[0110] like Figure 6B As shown, the working principle of the third circuit 160 is as follows: after the self-test is completed, the measurement and control signal S4 Driver is set high, and the reverse control switch control signal S A Driver is set high, reverse control switch S A The branch in question, namely the reverse branch 175, sends a reverse charging signal to the main charging circuit via the microcontroller unit (MCU) 178. This reverse charging signal is a PWM (pulse width modulation) wave. This initiates reverse pre-charging. The first anti-backflow switch S3 closes, and the voltage from the low-voltage battery 140 forms a loop through the second anti-reverse polarity switch S4, the first anti-backflow switch S3, the filter inductor L3, and the filter capacitor C3, storing energy in the filter inductor L3 and the filter capacitor C3.

[0111] like Figure 6C As shown, the operating principle of the third circuit 160 is as follows: when a reverse charging signal is received, a disconnect signal is sent to the first anti-backflow switch S3, causing the first anti-backflow switch S3 to disconnect. The filter inductor L3 forms a loop through the freewheeling diode D3 and the filter capacitor C3, and the filter capacitor C3 stores energy. During this process, the voltage of the filter capacitor C3 is controlled by the third circuit 160.

[0112] like Figure 6D As shown, the first secondary switch SR1 is closed, the current flowing through the first secondary inductor L1 is positive on the left and negative on the right, the filter capacitor C3 stores energy in the first secondary inductor L1, and the current in the first secondary inductor L1 increases linearly.

[0113] like Figure 6EAs shown, when the first secondary switch SR1 is turned off, the energy stored in the first secondary inductor L1 is released. The energy from the first secondary inductor L1 flows through the secondary winding of the main transformer (T1) 130 and the second secondary inductor L2 to form a closed loop. The voltage of the transformer 130 is negative at the top and positive at the bottom. The second primary switch P2, the first primary capacitor C1, and the bus capacitor C4 form a primary loop to charge the bus capacitor C4.

[0114] like Figure 6F As shown, the second secondary switch tube SR2 is closed, the current flowing through the second secondary inductor L2 is positive on the left and negative on the right, the filter capacitor C3 stores energy in the second secondary inductor L2, and the current in the second secondary inductor L2 increases linearly.

[0115] like Figure 6G As shown, the second secondary switch tube SR2 is disconnected, and the energy stored in the second secondary inductor L2 is released. The energy from the second secondary inductor flows through the secondary winding of the main transformer (T1) 130 and the first secondary inductor L1 to form a closed loop. The transformer voltage is positive at the top and negative at the bottom. The first primary switch tube P1, the second primary capacitor C2, and the bus capacitor C4 form a primary loop to charge the bus capacitor C4.

[0116] Figures 6D to 6G The working principle of reverse pre-charging is demonstrated: the first secondary inductor L1, the second secondary inductor L2, the first secondary switch tube SR1, the second secondary switch tube SR2, the main transformer (T1) 130, the first primary switch tube P1, the second primary switch tube P2, the first primary capacitor C1, and the second primary capacitor C2 constitute an isolated DC / DC circuit.

[0117] like Figure 6H As shown, it is detected that the primary voltage reaches the precharge threshold, the reverse precharge is completed, and the reverse control switch S A The microcontroller unit (MCU) 178 stops sending the PWM wave of the reverse charging signal. After detecting the high voltage connection, the reverse control switch control signal S A Driver is set low, the positive control switch control signal S C Driver is set high, that is, the forward branch where the Oring circuit is located is turned on, the second anti-reverse polarity switch tube S4 and the first anti-backflow switch tube S3 are closed, and DC / DC positive charging is performed. The positive branch outputs a positive charging signal to the main charging circuit.

[0118] In the fourth circuit 170, the reverse control switch control signal S can be ensured by the inverter 171. A Driver and forward control switch control signal S C The driver is set high or low, which is opposite. Then the selection circuit can make the signal received by the main charging circuit be either a reverse charging signal or a forward charging signal.

[0119] The second anti-reverse connection switch tube S4 and the first anti-backflow switch tube S3 arranged opposite to each other can prevent backflow in both directions and block the current when the switch tubes are closed.

[0120] The technical effect of the vehicle-mounted DC / DC converter provided by the present invention is to improve the safety of the vehicle-mounted charging device.

[0121] The above specific embodiments and accompanying drawings are merely illustrative of the technical solutions and effects of the present invention and are not intended to limit the present invention. Any person skilled in the art may modify or alter the above embodiments within the scope of the claims without violating the technical principles and spirit of the present invention, and all such modifications or alterations shall fall within the scope of protection of the present invention.

Claims

1. A vehicle-mounted DC / DC converter, characterized in that: include: Main transformer, including primary winding and secondary winding; a first circuit, one end of the first circuit being connected to the primary winding, and the other end of the first circuit being connected to a bus capacitor and a high-voltage battery of an on-board charging system; a second circuit, one end of the second circuit being connected to the secondary winding; a third circuit, one end of the third circuit being connected to the other end of the second circuit, and the other end of the third circuit being connected to a low-voltage battery of an on-board charging system, comprising a first anti-backflow switch tube and a second anti-reverse connection switch tube connected in series; The fourth circuit comprises: A micro control unit, the fourth terminal of which transmits the measurement and control signal to the control terminal of the second anti-reverse connection switch tube; a reverse branch, comprising a reverse control switch, one end of the reverse branch being connected to the first end of the microcontroller unit, and the other end being connected to the control end of the first anti-backflow switch tube, and the reverse branch being further configured to output a reverse charging control signal to the main charging circuit; a forward branch, comprising an Oring circuit and a forward control switch connected in series, one end of the forward branch being connected to the second end of the microcontroller unit, and the other end being connected to the control end of the first anti-backflow switch tube, and the forward branch being further configured to output a forward charging control signal to the main charging circuit; Inverter, the third end of the microcontroller directly outputs a reverse control switch control signal for controlling the reverse control switch, and the third end of the microcontroller also simultaneously outputs a forward control switch control signal for controlling the forward control switch through the inverter, wherein the main charging circuit can realize forward charging from the high-voltage battery to the low-voltage battery and reverse charging from the low-voltage battery to the bus capacitor.

2. The vehicle-mounted DC / DC converter according to claim 1, wherein: The first circuit includes: a first primary switching tube, one end of which is connected to the first end of the primary winding of the main transformer, and the other end of which is connected to the positive electrode of the high-voltage battery; a second primary switching tube, one end of which is connected to the first end of the primary winding of the main transformer, and the other end of which is connected to the negative electrode of the high-voltage battery; a first primary capacitor, one end of which is connected to the positive electrode of the high-voltage battery, and the other end of which is connected to the second end of the primary winding of the main transformer; a second primary capacitor, one end of which is connected to the negative electrode of the high-voltage battery, and the other end of which is connected to the second end of the primary winding of the main transformer; or a first primary switching tube, one end of the first primary switching tube is connected to the first end of the primary winding of the main transformer, and the other end of the first primary switching tube is connected to the positive electrode of the high-voltage battery; a second primary switching tube, one end of the second primary switching tube is connected to the first end of the primary winding of the main transformer, and the other end of the second primary switching tube is connected to the negative electrode of the high-voltage battery; a third primary switching tube, one end of the third primary switching tube is connected to the positive electrode of the high-voltage battery, and the other end of the third primary switching tube is connected to the second end of the primary winding of the main transformer; a fourth primary switching tube, one end of the fourth primary switching tube is connected to the negative electrode of the high-voltage battery, and the other end of the fourth primary switching tube is connected to the second end of the primary winding of the main transformer.

3. The vehicle-mounted DC / DC converter according to claim 1, wherein: The second circuit includes: a first secondary inductor, one end of the first secondary inductor is connected to the positive electrode of one end of the third circuit, and the other end of the first secondary inductor is connected to the second end of the secondary winding of the main transformer; a second secondary inductor, one end of the second secondary inductor is connected to the positive electrode of one end of the third circuit, and the other end of the second secondary inductor is connected to the first end of the secondary winding of the main transformer; a first secondary switch tube, one end of the first secondary switch tube is connected to the second end of the secondary winding, and the other end of the first secondary switch tube is connected to the negative electrode of the low-voltage battery; a second secondary switch tube, one end of the second secondary switch tube is connected to the first end of the secondary winding of the main transformer, and the other end of the second secondary switch tube is connected to the negative electrode of the low-voltage battery; or a fourth secondary inductor, one end of the fourth secondary inductor being connected to the positive electrode of one end of the third circuit; a third secondary switch tube, one end of the third secondary switch tube being connected to the other end of the fourth secondary inductor, and the other end of the third secondary switch tube being connected to the first end of the secondary winding of the main transformer; and a fourth secondary switch tube, one end of the fourth secondary switch tube being connected to the other end of the fourth secondary inductor, and the other end of the fourth secondary switch tube being connected to the second end of the secondary winding of the main transformer.

4. The vehicle-mounted DC / DC converter according to claim 1, wherein: The third circuit includes: A filter capacitor, the filter capacitor is connected in parallel with the second circuit; a filter inductor, one end of the filter inductor is connected to the first end of the filter capacitor; one end of the first anti-backflow switch tube is connected to the other end of the filter inductor, the other end of the first anti-backflow switch tube is connected to one end of the second anti-reverse polarity switch tube, the negative pole of the parasitic diode of the first anti-backflow switch tube is connected to the negative pole of the parasitic diode of the second anti-reverse polarity switch tube, the other end of the second anti-reverse polarity switch tube is connected to the positive pole of the low-voltage battery, and the fourth circuit output control connects the first anti-backflow switch tube and the second anti-reverse polarity switch tube; a freewheeling diode, the first end of the freewheeling diode is connected to the negative pole of the low-voltage battery, and the second end of the freewheeling diode is connected to the connection end of the first anti-backflow switch tube and the filter inductor.

5. The vehicle-mounted DC / DC converter according to claim 4, wherein: Based on the third circuit: A circuit in which a freewheeling switch tube and a diode are connected in parallel is used to replace the freewheeling diode, the anode of the diode connected in parallel with the freewheeling switch tube is connected to the negative electrode of the low-voltage battery, and the cathode of the diode connected in parallel with the freewheeling switch tube is connected to the connection end of the first anti-backflow switch tube and the filter inductor; or, a freewheeling switch tube is used to replace the freewheeling diode, the cathode of the diode connected in parallel with the freewheeling switch tube is connected to the negative electrode of the low-voltage battery, and the anode of the diode connected in parallel with the freewheeling switch tube is connected to the connection end of the first anti-backflow switch tube and the filter inductor; or, A circuit in which a freewheeling switch tube and a diode are connected in parallel and then in series with a freewheeling diode is used to replace the freewheeling diode, wherein the anode of the diode connected in parallel with the freewheeling switch tube is connected to the negative electrode of the low-voltage battery, the cathode of the diode connected in parallel with the freewheeling switch tube is connected to the anode of the freewheeling diode, and the cathode of the freewheeling diode is connected to the connection terminal of the first anti-backflow switch tube and the filter inductor; or A circuit in which a freewheeling switch tube and a diode are connected in parallel and then in series with a freewheeling diode is used to replace the freewheeling diode. The cathode of the diode connected in parallel with the freewheeling switch tube is connected to the negative electrode of the low-voltage battery, the anode of the diode connected in parallel with the freewheeling switch tube is connected to the anode of the freewheeling diode, and the cathode of the freewheeling diode is connected to the connection end of the first anti-backflow switch tube and the filter inductor.

6. The vehicle-mounted DC / DC converter according to claim 4 or 5, characterized in that: Based on the third circuit: A second switch is used to replace the second anti-reverse connection switch tube, one end of the first anti-backflow switch tube is connected to the other end of the filter inductor, the other end of the first anti-backflow switch tube is connected to one end of the second switch, the negative electrode of the parasitic diode of the first anti-backflow switch tube is connected to one end of the second switch, the other end of the second switch is connected to the positive electrode of the low-voltage battery, and the fourth circuit output control is connected to the first anti-backflow switch tube and the second switch.

7. The vehicle-mounted DC / DC converter according to claim 1, wherein: The micro control unit includes a first micro control unit, and one end of the reverse branch is connected to the first micro control unit; The micro control unit includes a second micro control unit, and one end of the forward branch is connected to the second micro control unit; The micro control unit includes a third micro control unit, and the inverter is connected to the third micro control unit; The micro control unit includes a fourth micro control unit, and the fourth micro control unit outputs the measurement and control signal; The first micro control unit, the second micro control unit, the third micro control unit, and the fourth micro control unit are independent micro control units that communicate with each other; or Any two, any three, or four of the first microcontroller unit, the second microcontroller unit, the third microcontroller unit, and the fourth microcontroller unit are integrated into an integrated microcontroller unit, and the internal subunits of the integrated microcontroller unit are communicatively connected, or the integrated microcontroller units are communicatively connected with each other, or the integrated microcontroller unit and a non-integrated microcontroller unit are communicatively connected.

8. The vehicle-mounted DC / DC converter according to claim 1, wherein: Based on the fourth circuit: a fifth microcontroller unit is used to replace the Oring circuit; The first micro control unit, the second micro control unit, the third micro control unit, the fourth micro control unit, and the fifth micro control unit are independent micro control units that communicate with each other; or Any two, any three, any four or five of the first microcontroller unit, the second microcontroller unit, the third microcontroller unit, the fourth microcontroller unit and the fifth microcontroller unit are integrated into an integrated microcontroller unit, and the internal subunits of the integrated microcontroller unit are communicatively connected, or the integrated microcontroller units are communicatively connected with each other, or the integrated microcontroller unit and a non-integrated microcontroller unit are communicatively connected.

9. The vehicle-mounted DC / DC converter according to claim 1, 7 or 8, wherein: The third circuit also includes a first sensing resistor and a second sensing resistor; one end of the first sensing resistor is connected to one end of the second anti-reverse switching tube or the second switch, the other end of the second anti-reverse switching tube or the second switch is connected to one end of the first anti-backflow switching tube, and the other end of the first anti-backflow switching tube is connected to one end of the second sensing resistor; The fourth circuit includes: a sixth microcontroller unit, the sixth microcontroller unit being connected to the other end of the first sensing resistor and the other end of the second sensing resistor to obtain corresponding voltage and current signals for controlling whether to turn on the second anti-reverse polarity switch tube or the second switch and to perform reverse charging and forward charging processes; The first micro control unit, the second micro control unit, the third micro control unit, the fourth micro control unit, the fifth micro control unit, and the sixth micro control unit are independent micro control units that communicate with each other; or Any two, any three, any four, any five or six of the first microcontroller unit, the second microcontroller unit, the third microcontroller unit, the fourth microcontroller unit, the fifth microcontroller unit and the sixth microcontroller unit are integrated into an integrated microcontroller unit, and the internal subunits of the integrated microcontroller unit are communicatively connected, or the integrated microcontroller units are communicatively connected with each other, or the integrated microcontroller unit and a non-integrated microcontroller unit are communicatively connected.

Images