CN104917222B - Electric-vehicle-mounted digital charger - Google Patents

Abstract

The present invention is applicable in electric automobiles, provides a kind of electric-vehicle-mounted digital charger, and the charger includes：Inverse-excitation type switch power-supply AC DC circuits, peak voltage absorption circuit, sampling feedback circuit, output constant current constant voltage circuit；Wherein, inverse-excitation type switch power-supply AC DC circuits are that electric energy transmits main circuit, the circuit is connect with peak voltage absorption circuit, sampling feedback circuit, output constant current constant voltage circuit respectively, and technical solution provided by the invention has the advantages that realize the unprecedented application of DC DC transformation with AC DC circuit topologies.

Description

Electric vehicle on-board digital charger

technical field

The invention belongs to the field of electric vehicles, in particular to an on-board digital charger for electric vehicles.

Background technique

Electric bicycles, that is, electric bicycles and electric motorcycles, refer to mechatronics that use batteries as auxiliary energy sources on the basis of ordinary bicycles, and are equipped with operating components such as motors, controllers, batteries, handlebars, brake handles, and display instrument systems. personal transportation. With the rapid development of electric vehicles, more and more users use electric vehicles, and electric vehicles have a huge mobile power supply capacity.

In the solutions of the prior art, it is found that the solutions of the prior art have the following technical problems:

The electric vehicles provided by the existing technology cannot provide on-board charging functions, which is very inconvenient for users, such as couriers, takeaway delivery people, and farmers riding to work in the fields. When electric vehicles travel for a long time, mobile phones, etc. The frequency of use of the device is very high, coupled with the increase in power consumption of smart phones, the battery drains faster, so now there is an urgent need for a digital charger that can charge electric vehicles at any time.

Contents of the invention

The purpose of the embodiments of the present invention is to provide an on-board digital charger for an electric vehicle, aiming to solve the problems that the electric vehicle in the prior art cannot perform on-board charging and the AC-DC circuit topology cannot realize low-voltage DC-DC conversion.

The embodiment of the present invention is achieved by providing an electric vehicle on-board digital charger, which includes: a flyback switching power supply AC-DC circuit, a peak voltage absorption circuit, a sampling feedback circuit, and an output constant current and constant voltage circuit ;in,

Optionally, the charger specifically includes: an input fuse, a resistor, a capacitor, a transformer, a diode, a bridge rectifier, a field effect transistor, a photocoupler, a current-mode PWM controller, and a built-in 2.5V reference operational amplifier; wherein,

F1 is the input fuse, and its function is to disconnect the charger circuit and the external electric vehicle battery power supply when the electrical failure of the subsequent stage circuit causes the current overload to flow through it; BD1 is a bridge rectifier, and its function is to connect the positive and negative The polarity of the DC voltage input is converted into a fixed positive and negative polarity DC voltage output, so as to realize the function of input regardless of positive and negative polarity; U1 is a current-type PWM controller, which is used to generate a PWM signal to drive the field effect transistor Q1 to work in the Control of switch status, over-current protection, over-voltage protection, overload protection, over-temperature protection, duty cycle modulation, etc.; reference operational amplifier U2 is a built-in 2.5V reference operational amplifier, which is used to collect output current and voltage signals, and The comparison result of the internal 2.5V reference voltage controls the conduction depth of the photocoupler U2, thereby indirectly controlling the duty cycle of U1, so that the output voltage and current are always kept at the set constant state.

It works as follows:

The IN1 and IN2 input terminals are connected to the charging/discharging port of the electric vehicle, and the electric vehicle battery provides power supply with a 30-120V DC voltage with variable positive and negative polarity, and the voltage is converted into a fixed positive and negative polarity 30-120V DC through the bridge rectifier BD1 The voltage output supplies power to the primary part of the circuit. After power-on, the starting resistor R6 works first. The fixed positive and negative polarity 30-120V output by the bridge rectifier BD1 generates current through R6 to charge the VCC filter capacitor C5. When the voltage on C5 is charged to When U1 starts to work at 16.5V (16.5V is the threshold start-up voltage of U1), after U1 starts to work, its 6-pin outputs a 50KHZ square wave pulse signal with a duty cycle of 0.35 through R7 and D3 to make Q1 operate at a frequency of 50KHZ with a duty cycle of 0.35. It is continuously turned on and off. When Q1 is turned on, the primary winding 2 and pin 1 of the high-frequency transformer T1 start to store energy. When Q1 is turned off, the primary winding of the transformer discharges the secondary winding and the AUX winding. After AUX is energized, it is rectified by D2. Low-frequency pulsating DC voltage, which is filtered by capacitor C5 and de-interferenced by C2 to supply power to pin 5 VDD of U1.

The secondary winding obtains 50KHZ high-frequency pulse voltage and rectifies it into a low-frequency pulsating DC voltage through D4. The pulsating DC voltage is filtered by capacitor C6 and becomes a smooth and pure DC voltage to supply power to U2A and U2 and provide power to the output port. At the same time, U2 will detect the output voltage and current in real time. If it is not within the set range, U2 will send a signal to change the conduction depth of U2A. After the conduction depth of U2A changes, its receiving end U2B will change the voltage of pin 2 of U1. When the voltage of pin 2 of U1 changes, it will internally adjust the conduction duty cycle of Q1 synchronously to keep the output stable.

In addition to the basic workflow mentioned above, after power-on, pins 2 and 4 of U1 are constantly detecting circuit parameters. When a certain item parameter exceeds the set range, U1 will automatically make corresponding adjustments to keep the output at 5V/ 1A to charge digital products.

In the embodiment of the present invention, the technical solution provided by the present invention has the advantage of using AC-DC circuit topology to realize unprecedented application of DC-DC conversion.

Description of drawings

Fig. 1 is the circuit block diagram of electric vehicle on-board digital charger provided by the present invention;

Fig. 2 is a schematic circuit diagram of the electric vehicle on-board digital charger provided by the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

The specific embodiment of the present invention provides a vehicle-mounted digital charger for an electric vehicle. As shown in Figure 1, the charger includes: a flyback switching power supply AC-DC circuit, a peak voltage absorption circuit, a sampling feedback circuit, and an output constant current and constant voltage circuit, wherein the flyback switching power supply AC-DC circuit is the main circuit for power transmission, which is respectively connected to the peak voltage absorption circuit, sampling feedback circuit, and output constant current and constant voltage circuit

The technical scheme provided by the invention provides an on-board charger on the electric vehicle, so it has the advantage of being able to charge the electric vehicle on-board.

Optionally, the above-mentioned charger specifically includes: an input fuse, a resistor, a capacitor, a transformer, a diode, a bridge rectifier, a field effect transistor, a photocoupler, a current-mode PWM controller, and a built-in 2.5V reference operational amplifier, wherein,

F1 is the input fuse, and its function is to disconnect the charger circuit and the external electric vehicle battery power supply when the electrical failure of the subsequent stage circuit causes the current overload to flow through it; BD1 is a bridge rectifier, and its function is to connect the positive and negative The polarity of the DC voltage input is converted into a fixed positive and negative polarity of the DC voltage output, so as to realize the function of input regardless of the positive and negative poles; U1 is a current-type PWM controller, which is used to generate a PWM signal to drive the field effect transistor Q1 to work in the Control of switch status, over-current protection, over-voltage protection, overload protection, over-temperature protection, duty cycle modulation, etc.; U2 is a built-in 2.5V reference operational amplifier, which is used to collect output current and voltage signals, through and internal 2.5V The comparison result of the reference voltage controls the conduction depth of the optocoupler U2, thereby indirectly controlling the duty cycle of U1, so that the output voltage and current are always kept at the set constant state.

The charger is shown in Figure 2, including: input fuse, resistor, capacitor, transformer, diode, bridge rectifier, field effect tube, photocoupler, current-mode PWM controller, and built-in 2.5V reference operational amplifier;

The connection characteristics of the primary side of the circuit: the two ends of the input fuse F1 are respectively connected to the input IN1 port and the AC terminal of the bridge rectifier BD1; One end of resistor R1 and absorbing capacitor C1 is connected; pin 1 of current-mode PWM controller U1 is connected to the primary ground wire; pin 2 of U1 is connected to the phototransistor collector of photocoupler U2B and one end of low-pass filter capacitor C3; Pin 1 is connected to one end of pulse frequency setting resistor R2; pin 4 of U1 is connected to one end of capacitor C4 and one end of resistor R4 in the peak current detection RC network; pin 5 of U1 is connected to the other end of starting resistor R6 and VCC filter network C5 and One end of R5 and pin 6 of U1 are connected to one end of the driving resistor R7 and the cathode of the fast turn-off diode D3, and the other end of R7 and the anode of D3 are connected to the gate of the field effect transistor Q1; the drain of the field effect transistor Q1 is connected to To the high-frequency transformer T1 primary winding pin 2 and the anode of the absorption diode D1; the cathode of the absorption diode D1 is connected to the other end of R1 and C1; the peak current detection resistors R3A and R3B are connected in parallel, and the lower end is connected to the primary ground wire, and the upper end is connected to the field effect tube The source of Q1 is connected to the other end of resistor R4; the pin 4 of the AUX winding of the high-frequency transformer T1 is connected to the primary ground wire, and the pin 3 of the high-frequency transformer T1 is connected to the anode of the VCC rectifier diode D2; the cathode of the rectifier diode D2 is connected to the other end of the resistor R5 One end connection;

The connection characteristics of the secondary side of the circuit: the 7-pin of the secondary winding of the high-frequency transformer T1 is connected to the secondary ground wire, the 5-pin of T1 is connected to the anode of the output rectifier diode D4; the other end of the output filter capacitor C6 and the output high-frequency suppression capacitor C7 are connected to the secondary One end of C6 and C7 is connected to the cathode of the output rectifier diode D4 and pin 1 of the output port USB1; after the output current detection resistors R8A and R8B are connected in parallel, the left end is connected to the secondary ground wire, and the right end is connected to the 4 pin of the output port USB1 and the feedback resistor One end of R13; pin 2 and pin 3 of the output port USB1 are short-circuited; pin 1 of the built-in 2.5V reference operational amplifier U2 is connected to the common point of the output voltage detection resistors R10, R11 and negative feedback resistor R12; pin 2 of U2 is connected to the output voltage The detection resistor R10 is connected to the right end of the parallel network with R8A and R8B, the 4 pins of the output port USB1, and the feedback resistor R13 are connected to the common point; the 3 pins of U2 are connected to the common point of the current limiting resistor R9 and C8, C9; the 4 pins of U2 are connected to the secondary Level ground wire, the 5th pin of U2 is connected to the other end of the feedback resistor R13 and the other end of the negative feedback resistor R14; the 6th pin of U2 is connected to the output voltage detection resistor R11, the positive pole of the photocoupler U2A light-emitting diode, the negative pole of the output rectifier diode D4, The output filter capacitor C6 and the output high-frequency suppression capacitor C7 are connected to the common point of the pin 1 of the output port USB1; the negative electrode of the light-emitting diode of the photocoupler is connected to one end of the current limiting resistor R9; the other end of the negative feedback resistor R12 is connected to the negative feedback capacitor C8 The other end is connected; one end of the negative feedback resistor R14 is connected to the other end of the negative feedback capacitor C9.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (1)

1. An on-board digital charger for an electric vehicle, the charger comprising: the flyback switching power supply comprises a flyback switching power supply AC-DC circuit, a peak voltage absorption circuit, a sampling feedback circuit and an output constant current and constant voltage circuit; the flyback switching power supply AC-DC circuit is a main electric energy transmission circuit, and the main circuit is respectively connected with a peak voltage absorption circuit, a sampling feedback circuit and an output constant current and constant voltage circuit; the charger specifically includes: the input protective tube, a resistor, a capacitor, a transformer, a diode, a bridge rectifier, a field effect tube, a photoelectric coupler, a current type PWM controller and a built-in 2.5V reference operational amplifier;

circuit primary side connection feature: two ends of the input fuse F1 are respectively connected with the input IN1 port and the AC end of the bridge rectifier BD 1; the DC end of the bridge rectifier BD1 is connected with one end of a pin 1 of a primary winding of a high-frequency transformer T1, a starting resistor R6, an absorption resistor R1 and an absorption capacitor C1; pin 1 of the current-mode PWM controller U1 is connected with a primary ground wire; a pin 2 of the U1 is connected with a collector of a phototriode of a photoelectric coupler U2-B and one end of a low-pass filter capacitor C3; the 3 pin of U1 is connected with one end of a pulse frequency setting resistor R2; the 4 pins of the U1 are connected with one end of a capacitor C4 and one end of a resistor R4 in the peak current detection RC network; a pin 5 of the U1 is connected with the other end of the starting resistor R6 and one ends of VCC filter networks C5 and R5, a pin 6 of the U1 is connected with one end of a driving resistor R7 and the cathode of a fast turn-off diode D3, and the other end of the R7 and the anode of the D3 are both connected with the gate of a field effect transistor Q1; the drain electrode of the field effect transistor Q1 is connected to the pin 2 of the primary winding of the high-frequency transformer T1 and the anode of the absorption diode D1; the cathode of the absorption diode D1 is connected with the other ends of R1 and C1; the lower end of the spike current detection resistors R3A and R3B are connected with a primary ground wire after being connected in parallel, and the upper end of the spike current detection resistors is connected with the source electrode of the field effect transistor Q1 and the other end of the resistor R4; the pin 4 of the auxiliary winding of the high-frequency transformer T1 is connected with a primary ground wire, and the pin 3 of the high-frequency transformer T1 is connected with the positive pole of a VCC rectifying diode D2; the cathode of the rectifier diode D2 is connected with the other end of the resistor R5;

circuit secondary side connection feature: a pin 7 of a secondary winding of the high-frequency transformer T1 is connected with a secondary ground wire, and a pin 5 of the T1 is connected with an anode of an output rectifier diode D4; the other ends of the output filter capacitor C6 and the output high-frequency suppression capacitor C7 are connected with a secondary ground wire, and one ends of C6 and C7 are connected with the cathode of the output rectifier diode D4 and a pin 1 of the output port USB 1; the output current detection resistors R8A and R8B are connected in parallel, the left end of the output current detection resistor is connected with a secondary ground wire, and the right end of the output current detection resistor is connected with the 4 pins of the output port USB1 and one end of the feedback resistor R13; pins 2 and 3 of the output port USB1 are short-circuited; a pin 1 of the built-in 2.5V reference operational amplifier U2 is connected with a common point of the output voltage detection resistors R10, R11 and the negative feedback resistor R12; the 2 pin of the reference operational amplifier U2 is connected with the common point of the parallel network right end of the output voltage detection resistors R10, R8A and R8B, the 4 pin of the output port USB1 and the feedback resistor R13; the pin 3 of the reference operational amplifier U2 is connected with the common point of the connection of the current limiting resistor R9, the C8 and the C9; a pin 4 of the reference operational amplifier U2 is connected with a secondary ground wire, and a pin 5 of the reference operational amplifier U2 is connected with the other end of the feedback resistor R13 and the other end of the negative feedback resistor R14; the 6 pins of the reference operational amplifier U2 are connected with a common point for connecting the output voltage detection resistor R11, the positive electrode of the light emitting diode of the photoelectric coupler U2-A, the negative electrode of the output rectifier diode D4, the output filter capacitor C6, the output high-frequency suppression capacitor C7 and the 1 pin of the output port USB 1; the negative electrode of the light emitting diode of the photoelectric coupler is connected with one end of a current limiting resistor R9; the other end of the negative feedback resistor R12 is connected with the other end of the negative feedback capacitor C8; one end of a negative feedback resistor R14 is connected with the other end of a negative feedback capacitor C9, one end of a negative feedback capacitor C9 is connected with one end of a negative feedback capacitor C8, and the other end of the negative feedback resistor R14 is connected with the other end of a feedback resistor R13;

the other end of the third capacitor C3, the other end of the second resistor R2, the other end of the fourth capacitor C4, the other end of the fifth capacitor C5 and the drain electrode of the photoelectric coupler U2-B are all connected with a primary ground wire;

the second capacitor C2 is connected between the No. 1 pin and the No. 5 pin of the U1, and the upper end of the spike current detection resistors R3A and R3B is connected with the other end of the fourth resistor R4 after being connected in parallel;

the other end of the ninth resistor R9 is connected with pin No. 3 of U2, one end of the twelfth resistor R12 is connected with pin No. 1 of U2, one end of the tenth resistor R10 is connected with pin No. 2 of U2, the other end of the tenth resistor R10 is connected with pin No. 1 of U2, one end of the eleventh resistor R11 is connected with pin No. 1 of U2, and the other end of the eleventh resistor R11 is connected with pin No. 6 of U2.