KR20200031437A - Ac-dc converter for charger of electrical vehicle battery - Google Patents

Abstract

The present invention relates to an electric vehicle battery charging technology, and more particularly, to an AC-DC converter for charging an electric vehicle battery, which improves efficiency to allow a power factor (PF) to be close to 1. According to an embodiment of the present invention, the AC-DC converter comprises: an input unit (1) for correcting a power factor of an input power AC power to 0.9 to 1, and then rectifying the same to a DC power to output the same; an output unit (2) for receiving an output DC power of the input unit (1), performing synchronous rectification and active clamp to achieve zero voltage switching, performing DC-DC conversion with voltage required for battery charging to output the same, and having an active clamp snubber circuit; and a bias supply unit (3) for supplying power for driving the input unit (1) and the output unit (2). The output unit (2) includes a full-bridge circuit for zero voltage switching, and each leg of a bridge circuit is driven with two complementary PWM signals having 50% of a fixed duty and includes an inverter unit (80) having a first current transformer (CT1) for output and short-circuit current detection of a full-bridge.

Description

AC-DC converter for electric vehicle battery charging {AC-DC CONVERTER FOR CHARGER OF ELECTRICAL VEHICLE BATTERY}

The present invention relates to an electric vehicle battery charging technology, and more particularly, to an AC-DC converter for electric vehicle battery charging with improved efficiency such that the power factor (PF) is close to 1.

Electric vehicle (EV) refers to a vehicle that does not use petroleum fuel and engine, but uses an electric battery and an electric motor.

Electric vehicles mainly include electric vehicles that use only electric batteries, and hybrid electric vehicles that use other power sources, such as gasoline and electric batteries, together. An electric vehicle that drives a vehicle by rotating a motor with electricity accumulated in a battery was built before the gasoline vehicle in 1873. However, due to problems such as the heavy weight of the battery and the time it takes to charge, it has not been put into practical use.

Recently, research on electric vehicles has been actively conducted due to a lack of energy resources such as fossil fuels and environmental pollution caused by gasoline vehicles.

In order to expand and promote the operation of electric vehicles, it is essential to build a charging infrastructure, and development of a charging stand and a charging system, which are electric power transmission devices, is essential.

In order to output a voltage suitable for charging the battery for an electric vehicle, the AC-DC converter rectifies the charging power from AC to DC, and then converts the rectified DC power to DC-DC with a voltage suitable for battery charging. It entails a process.

These AC-DC converters for battery charging for electric vehicles require high efficiency over the entire load operating range and main input voltage range.

Accordingly, Korean Patent Publication No. 2017-0131895 provides an electric vehicle charging and power conversion combined circuit that simplifies the circuit configuration and reduces losses by using an insulated power factor correction converter. 0017987 discloses a battery charging device for an electric vehicle that is configured to correct and output a power factor through a power factor correction circuit.

However, the above-mentioned prior arts have a problem that they do not meet the demand for high efficiency over the entire load operating range and the main input voltage range of the AC-DC converter for battery charging for electric vehicles.

Republic of Korea Patent Publication No. 2017-0131895 Republic of Korea Patent No. 2018-0017987

An embodiment of the present invention for solving the above-described problems of the prior art, the AC-DC converter for charging the battery for the electric vehicle is an electric vehicle battery having a high efficiency required over the entire load operation range and the main input voltage range It is an object to provide a charging AC-DC converter.

In order to achieve the above object, the present invention is to correct the power factor of the input power AC power to 0.9 to 1, and then rectified with a DC power to output; After receiving the output DC power of the input unit, after performing synchronous rectification and active clamping to achieve zero voltage switching, DC-DC is converted to a voltage required for charging the battery, and output, and an output unit having an active clamp snubber circuit ; And a bias supply unit supplying power for driving the input unit and the output unit.

The output unit is configured to include a full-bridge circuit for zero voltage switching, and each leg of the bridge circuit is configured to be driven by two complementary PWM signals having a fixed 50% duty, and output And an inverter unit having a first current transformer (CT1) for detecting a short-circuit current of a full bridge.

In addition, according to the AC-DC converter for charging the electric vehicle battery of the present invention, the input unit is configured to be connected to the input diode rectifier bridge diode of the PFC with two filters (F1, F2) having different frequency bands in two stages. EMC filter unit to alleviate interference; It is equipped with a first relay (RL1A) connected in parallel with a first thermistor (PT1) connected to the AC power input terminal, internally by the resistance value of the first thermistor (PT1) to limit the inrush current when input power to the input terminal An inrush current limiting unit for limiting the charging current of the capacitor, detecting the VBUS voltage, detecting that the voltage is normal, and then driving the first relay RL1A to limit inflow of the inrush current; An input rectifying unit comprising an eleventh capacitor (C11) composed of a full bridge diode and a pair of parallel connected capacitors connected in parallel with the full bridge diode to rectify and output AC power input from the EMC filter unit to DC power. ; An input voltage current detection unit which detects input AC voltage and current and outputs the input voltage to the input unit control unit for backflow compensation control; Includes two parallel boost converters (BC1, BC2) and two current transformers (CT1, CT2) connected to each switch to measure the average inductor current for each leg of the two parallel boost converters (BC1, BC2). , Power factor compensation two-phase boost converter unit that drives the switches of each leg with the same duty cycle, receives AC power filtered from the EMC filter unit through a RECT + port, and rectifies and outputs DC power; And high voltage DC bus voltage detection includes DC voltage voltage detection and filter unit that detects with voltage divider resistors (R24, R27, R29, R33, R34, R35) and outputs them to the VBUS + port of the MCU board constituting the input control unit. Can be configured.

In addition, according to the AC-DC converter for charging an electric vehicle battery of the present invention, the input unit includes a phase-locked loop (PLL) for PFC control for a power factor-compensated two-phase boost converter unit, and input voltage frequency, amplitude Low total harmonic distortion even when operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) by calculating and ensuring synchronization with the input current and introducing duty cycle feed-forward control technology It may be configured to further include; THD) and the input unit control unit for controlling the input power of the input unit so that the power factor (PF) is 0.9 to 1 in the entire operating range.

Further, according to the AC-DC converter for charging an electric vehicle battery of the present invention, the output section includes four first to fourth bridge circuits each including one of the first to fourth switches Q1, Q2, Q3, and Q4. An inverter unit having a full-bridge circuit having (BC1 to BC4) to perform ZVS switching to convert DC power output from the input unit 1 to AC power; A second gate driver unit supplying driving power to the inverter unit; An active clamp snubber part configured as a clamp network in a phase-locked rectifier circuit, which is an output rectifier, for clamping voltage spikes due to leakage inductance and diode junction capacitance of the first transformer T1; A third gate driver unit supplying driving power to the active clamp snubber unit; A phase-locked rectifying circuit unit converting the output AC power of the inverter unit into a DC by outputting a phase-locked current; A fourth gate driver unit supplying driving power to the phase-locked rectification circuit unit; An output current detection unit having a first low-resistance classifier (SH1) that detects the current of the output DC power of the phase-locked rectifier circuit and outputs it to DDC_CURR (MCU A / D) of the output unit control unit; An output filter and a voltage detection unit having a high-frequency circuit including a first inductor L1 and tenth to fifteenth capacitors C10 to C15 to filter high-frequency switching waveforms with DC power and supply them as output; And first to fourth inverter PWM signals (PWM_Q1, PWM_Q2.PWM_Q3, PWM_Q4) and the phase synchronous rectification for switching control of the first to fourth switches Q1, Q2, Q3, Q3 for the ZVS of the inverter unit. First to second phase-locked rectification PWM signals (PWM_SR1 (SRA1, SRB1)) for switching control of the eighth and tenth switches Q8 and Q10 and the ninth and eleventh switches Q9 and Q11 configured in the circuit unit, PWM_SR2 (SRA2, SRB2)), outputs first and second clamp PWM signals (PWM_CLAMP1, PWM_CLAMP2) for switching control of the fifth and sixth switches (Q5, Q6) of the active clamp snubber part, and outputs DC- It is configured to include; an output unit control unit for controlling switching and ZVS for DC conversion.

Further, according to the AC-DC converter for charging an electric vehicle battery of the present invention, the inverter unit includes four first to fourth bridges each including one of the first to fourth switches Q1, Q2, Q3, and Q4. A full-bridge circuit having circuits BC1 to BC4, a first current transformer CT1 for current detection of the full-bridge circuit, and a coupling node (a) of the second and fourth bridge circuits BC2 and BC4 of the full-bridge circuit The fourth inductor (L4) connected to the first transformer (T1) is connected to the coupling node (b) of the first and third bridge circuits (BC1, BC3) and the other end is connected to the fourth inductor Including, by means of two complementary PWM signals with each leg having a fixed 50% Duty, the third and fourth switches Q3 and Q4 are driven with a fixed 50% duty cycle, and the upper first and The pulse widths at the ends of the pulse widths of the second switches Q1 and Q2 may be driven to be modulated to be configured to perform ZVS.

According to an embodiment of the present invention described above, the AC-DC converter for charging an electric vehicle battery to provide a stabilized DC output voltage of 400 Vdc while adjusting the power factor of the input power to approximate 1 and reducing harmonic THD. It provides the effect of significantly improving the efficiency.

1 is a functional block diagram of an AC-DC converter according to an embodiment of the present invention.
2 is a circuit diagram showing a part of the configuration of the input unit of the configuration of FIG.
FIG. 3 is a detailed circuit diagram of an input unit controller in the configuration of FIG. 1.
4 is a circuit diagram of the output unit of the configuration of FIG.
5 is a view showing the output waveform of the inverter portion of the output.
6 is a detailed circuit diagram of the output current detection unit of the output unit
7 is a circuit diagram of a second gate driver unit for driving the switching element of the inverter unit of the configuration of the output unit.
8 is a circuit diagram of a third gate driver unit for driving the switching element of the activator clamp snubber unit in the configuration of the output unit.
9 is a circuit diagram of a fourth gate driver unit for driving a switching element of a phase-locked rectifier circuit among the components of the output unit.
10 is a circuit diagram of the output control unit in the configuration of the output unit.
11 is a circuit configuration diagram of a communication unit that performs communication between the input unit and the output unit.
12 is a circuit diagram of the bias supply of FIG. 1;

In the following description of the present invention, when it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

Embodiments according to the concept of the present invention may be applied to various changes and may have various forms, and thus, specific embodiments will be illustrated in the drawings and described in detail in the present specification or application. However, this is not intended to limit the embodiment according to the concept of the present invention to a specific disclosure form, and it should be understood that it includes all modifications, equivalents, or substitutes included in the spirit and scope of the present invention.

When an element is said to be "connected" or "connected" to another component, it is understood that other components may be directly connected to or connected to the other component, but may exist in the middle. It should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that no other component exists in the middle. Other expressions describing the relationship between the components, such as "between" and "immediately between" or "adjacent to" and "directly neighboring to," should be interpreted similarly.

The terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "include" or "have" are intended to indicate that a feature, number, step, action, component, part, or combination thereof described is present, and one or more other features or numbers. It should be understood that it does not preclude the presence or addition possibilities of, steps, actions, components, parts or combinations thereof.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings showing embodiments of the present invention.

First, an abbreviation used in the description of the embodiment of the present invention is defined.

PFC: Power Factor Corrector

THD: Total Harmonic Distortion

MCU: Micro controller unit

ZVS: Zero Voltage Switching

CCM: Continuous Conduction Mode

DCM: Discontinuous Conduction Mode

EMC: Electromagnetic Compatibility

PWM: Pulse Width Modulation

CT: Current Transformer

SMPS: Switched Mode Power Supplies

1 is a functional block diagram of an AC-DC converter according to an embodiment of the present invention.

As shown in FIG. 1, the AC-DC converter according to an embodiment of the present invention makes an input power factor of 1, reduces harmonic total harmonic distortion (THD), and stabilizes a 400 Vdc voltage for charging an electric vehicle battery. DC-DC conversion to a voltage required for battery charging after performing synchronous rectification to achieve zero voltage switching (ZVS) by receiving the DC power output from the input unit (1) that outputs DC power, And an output unit 2 for outputting and a bias supply unit 3 for supplying bias power for driving the input unit 1 and the output unit 2.

When the reduction of THD is described, the harmonic component of the input current increases due to distortion of the sinusoidal current in a capacitor load rectifier, which is basically a nonlinear load. In this development product, by applying digital control Active PFC, the reference of sinωt (see Fig. 3) is made and controlled so that the input current flows as a sinusoidal current synchronized with the input voltage waveform, thereby controlling with a single power factor and achieving low THDi.

In order to control with the unity power factor, the maximum input voltage is 373V (220Vac * 1.2 * 1.414 ≒ 373) due to the circuit characteristics, so it consists of a boost converter with an output voltage of 400 VDC.The circuit configuration is L3, It consists of L4 (boost inductor) and Q2, Q3, Q4, Q5 (switch) and D4, D5 (boost diode).

The input unit 1 is an EMC filter unit 10, an input voltage current detection unit 30, an inrush current limiting unit 15, a power factor compensation two-phase boost converter unit 40, a DC voltage voltage detection and filter unit 50 , It comprises a second gate driver unit 60 and the input unit control unit 70, to make the input power factor to 1, reduce the harmonic THD and stabilize the DC output voltage to 400Vdc to output.

The output unit 2 is composed of a DC-DC converter composed of a full bridge step-down converter driven by phase shift modulation (phase shift modulation), the inverter unit 80, the second Gate driver section 90, active clamp snubber section 100, third gate driver section 110, synchronous rectification circuit section 120, fourth gate driver section 130, output current detection section 140, output filter and It comprises a voltage detection unit 150, and an output unit control unit 160.

The output unit 2 of the above-described configuration lowers the PFC output voltage from 400V to a charging voltage for charging the battery, and provides electrical insulation using a high-frequency transformer. Phase shift modulation applied to the output unit 2 achieves Zero Voltage Switching (ZVS) and minimizes turn-on switching loss, unlike classic PWM modulation, which has significant power loss, such as hard switching. For this reason, full bridge phase shifted converters are suitable for high power and high frequency applications.

In addition, the output section 2 maximized efficiency by adopting a phase-locked rectification method and an active clamp snubber method, and a total efficiency of about 2% due to the adoption of a circuit for the implementation of the phase-locked rectification method and the active clamp snubber method. This was increased.

Next, each configuration of the AC-DC converter of the embodiment of the present invention will be described in more detail with reference to the accompanying drawings showing detailed circuits.

FIG. 2 shows the EMC filter unit 10, the inrush current limiting unit 15, the input rectifying unit 20, the input voltage current detecting unit 30, and the power factor compensation two-phase booster converter unit during the configuration of the input unit 1 in FIG. 1. (40), a circuit diagram including the DC voltage detection and filter section 50.

As shown in FIG. 2, the EMC filter unit 10 is configured to be connected to the input rectifier bridge diode of the PFC using two filters (F1, F2) having different frequency bands as two stages, and has a function of mitigating electromagnetic interference. Perform. The filter applied at this time is preferably designed to satisfy Class A (for industrial use) or Class B (for home use) depending on the application.

Specifically, EMC (Electro Magnetic Compatibility) should be designed to correspond to the EMC classification listed in Table 1 below. Accordingly, in the present invention, L, C is composed of L1, L2, C9, C7, C15, C5, C13, and C14 on the drawing in order to reduce the high frequency of the EMI component.

The inrush current limiter 15 has a first relay RL1A connected in parallel with a first thermistor PT1 connected to an AC power input terminal, so that the first thermistor PT1 for limiting inrush current when input power is supplied ) Limits the charging current of the internal capacitors (C19 and C20 on the input (1) side, C6 and C7 on the output (2) side) by the resistance value of), detects the VBUS voltage, and detects that the voltage is normal. By driving (RL1A), inrush current is prevented from flowing. Specifically, when the AC input is input in the initial state, the current flow is made of PT1-> BD1-> D3, and the charging current flows through the large-capacity capacitors (C19, C20 on the input side and C6, C7 on the output side). do. At this time, if there is no resistance of PT1, the initial short-circuit current of the large-capacity capacitor may occur, and the input fuse (F1) may be disconnected. Transient voltage and current of the input may occur, and after using PT1 to reduce the charging current at the initial start-up. After the charging voltage reaches a certain voltage, the first relay RL1 is operated to take charge of the operating current of the charger.

The input rectifier 20 includes an eleventh capacitor C11 composed of a full bridge diode and a pair of parallel connected capacitors connected in parallel with the full bridge diode, and a power factor correction 2-phase boost that is a PFC stage through the RECT + port. The pulse voltage is transmitted to the converter unit 40.

The input voltage current detection unit 30 detects input AC voltage and dry current for control of reverse current compensation and outputs them to the MCU board constituting the input unit control unit 70, the input voltage detection unit 31 and the input current detection unit 32 It is configured to include.

The input voltage detection unit 31 is an MCU that configures an input unit control unit 70 to detect a signal that is level-shifted to DC 1.25 V as an output of a first amplifier (OP-Amp, OP) by directly detecting an AC voltage. Send through the PFC_VAC port on the board,

The input current detector 32 amplifies the voltage of the shunt resistor SH1 and is transmitted to the PFC_i_AVG port of the MCU board constituting the input controller 70. Both signals are used as important control variables to make the power factor control of the input to 1, and are variables that require accuracy.

The power factor compensation two-phase boost converter unit 40 includes two parallel boost converters (BC1, BC2) that receive filtered power through the EMC filter unit 10 through the RECT + port and rectify AC power into DC power. It is configured to.

The power factor correction two-phase boost converter section 40 is connected to each switch to measure the average inductor current for each leg of two parallel boost converters BC1 and BC2 and two parallel boost converters BC1 and BC2. It consists of two current transformers (CT1, CT2), dividing the total current in an interleaved (180 ° phase shift) manner and reducing the high frequency ripple of the line and DC link capacitor currents. Therefore, this topology has the advantage of reducing the size of the input inductors (L3, L4) and the size of the output filter capacitors (C21, C22) and increases the converter power density.

In order to adjust the bus voltage, a voltage and current control loop (see FIG. 3) configured in the input unit control unit 70 is provided, and the voltage and current control loop 70 is an external voltage loop (71). The current control that is controlled using and forms a current according to a sinusoidal wave includes an internal current loop 72. The external voltage control loop 72 adjusts the current reference to maintain the specified bus voltage. By constructing the internal current control loop 72, there is a quick advantage in transient response and exhibits a ripple voltage reduction effect.

Two different current feedback measurements allow an independent current loop for each leg of the converter. Instead of the two CTs (CT1 and CT2), the firmware can be configured to use the total current flowing through the first shunt resistor (SH1) to perform a unique current loop, and the switches of both legs can be driven with the same duty cycle.

The high-voltage DC bus is regulated to 400 V by a power factor compensation two-phase boost converter 40 that is a PFC. While maintaining high power factor and low current, THDi maintains the total harmonic distortion of sinusoidal input current from AC input within 5%.

This circuit is designed to accept a wide range (90Vac to 264Vac) of input line voltage.

The DC voltage detection and filter unit 50 detects the high voltage DC bus voltage with the divided voltage resistors (R24, R27, R29, R33, R34, R35), and then VBUS + of the MCU board constituting the input unit control unit 70 Output to the port.

The DC voltage detection and filter unit 50 is provided with large-capacity electrolytic capacitors C19 and C20 for high-voltage filters for voltage detection, and these large-capacity electrolytic capacitors C19 and C20 constitute an output unit control unit 160 The output board is also arranged and operated. The large-capacity electrolytic capacitors C19 and C20 form a pulsating current by rectifying an AC voltage, and function to store energy as a filter for converting it into a DC component.

The first gate driver unit 60 is a second, third, fourth and fifth input unit of the reverse-flow compensation two-phase boost converter unit 40 implemented with a MOSFET of the 3.3 V PWM small signal of the input unit control unit 70 It is amplified and output by the driving signals of the switches Qi2, Qi3, Qi4 and Qi5, and is driven to 12 V for this.

3 is a detailed circuit diagram of the input unit control unit 70 in the configuration of FIG. 1.

The input unit control unit 70 includes an input unit MCU circuit, and the input unit MCU circuit comprises a phase-locked loop (PLL) for PFC control of the power factor compensation two-phase boost converter unit 40. The phase-locked loop (PLL) was implemented to calculate the input voltage frequency, amplitude, and ensure synchronization with the input current, and also introduced a duty cycle feed-forward control technology to achieve continuous conduction mode ( CCM), even when operating in discontinuous conduction mode (DCM), controls the input power of the input unit 1 so that the low total harmonic distortion (THD) and power factor (PF) are close to 1 over the entire operating range. The input unit MCU has a communication function with the secondary-side output board and operates by sharing the status information of the input board with the secondary-side output unit MCU.

FIG. 4 shows the inverter section 80, the active clamp snubber section 100, the phase-phase synchronous rectification circuit section 120, the output current detection section 140 and the output filter and voltage detection section of the output section 2 of the configuration of FIG. 150).

The inverter unit 80 has a full bridge circuit and outputs having four first to fourth bridge circuits BC1 to BC4 each including one of the first to fourth switches Q1, Q2, Q3, and Q4, and The fourth inductor L4 connected to the coupling node a of the first current transformer CT1 for detecting the short-circuit current of the full bridge and the second and fourth bridge circuits BC2 and BC4 of the full-bridge circuit, and one end of the above Each leg is fixed including a first transformer T1 connected to a fourth inductor 14 and the other end connected to a coupling node b of the first and third bridge circuits BC1 and BC3. It is configured to be driven by two complementary PWM signals with 50% duty.

The inverter unit 800 composed of the above-described full bridge implements zero voltage switching (ZVS), and for this purpose, operates similarly to the hard switching topology of the prior art, but has diagonal bridge switches BC1 and BC4, BC2 and BC3. ) Instead of driving simultaneously, the lower third and fourth switches Q3 and Q4 are driven with a fixed 50% duty cycle, and the pulse width is modulated at the pulse width ends of the upper first and second switches Q1 and Q2. By doing this, ZVS is performed to convert the output high-voltage DC power supply to the AC power supply.

Internal parallel diodes and parasitic capacitances are modeled on the first to fourth switches Q1, Q2, Q3, and Q4 of FIG. 4, which are composed of MOSFETs. In addition, the external resonant inductor LR includes a fourth inductor 14 and a T1 transformer leakage inductance LR.

FIG. 5 is a diagram showing the output waveform of the zero voltage switching (ZVS) full bridge of the inverter unit 80 of the output unit 2 having the above-described configuration.

As shown in FIG. 5, during the initial driving, the first and fourth switches Q1 and Q4 are turned on, and the second and third switches Q2 and Q3 are turned off. By this configuration, the first power transmission period is formed until the first switch Q1 is turned off, and the primary current flowing in this period is the first transformer T1 primary-L4-fourth switch Q4. Flows through. The first power transmission period ends when the first switch Q1 is turned off by the PWM signal. In this case, the current flowing through the primary side cannot be instantaneously cut off, so an alternative path is sought to flow through the parasitic switch capacitance of the third switch (Q3) and the first switch (Q1), discharge the node b to 0 V, and then switch to the third switch. The third diode D3, which is the body diode of (Q), is forward biased.

The primary resonant inductor LR maintains a current circulating through the path of the third diode D3, the primary transformer T1 primary-LR-fourth switch Q4. When the first switch Q1 is turned on, energy is transmitted to the output. Zero voltage switching (ZVS) switching occurs during a resonance delay period before the second switch Q2 is turned on after the third switch Q3 and the fourth switch Q4 are toggled. The required resonance delay is the LR × C of the circuit formed by the capacity of the first resonant inductor (L4) (?) And the parasitic capacitor (LR is L4 + T1 transformer leakage inductance, C is the parasitic capacitor inside Q2 and Q4). It is 1/4 of the cycle.

The active clamp snubber part 100 is configured as a clamp network in the phase rectifier rectifier circuit 120, which is an output rectifier, for clamping voltage spikes due to leakage inductance and diode junction capacitance of the first transformer T1. In the case of the prior art, a structure in which a large amount of heat loss is generated by using a passive snubber composed of RCD. In the case of the AC-DC converter of the present invention, one configuration of an active snubber network (D5, D6, Q5, Q6, C3, C4 L1, L2, D10, D11) was formed. C3) and the energy accumulated in the fourth capacitor C4 is the fifth and sixth switches Q5 and Q6-> first and second inductors L1 and L2-> ten and eleven diode pairs 10, D11).

The phase-locked rectifier circuit 120 is a fifth connected to each of the eighth to eleventh switches (Q8, Q9, Q10, Q11) and the eighth to eleventh switches (Q8, Q9, Q10, Q11), respectively. It comprises a to eighth bidirectional zener diodes (RV5, RV6, RV 7 RV8).

Specifically, the phase-locked rectification circuit unit 120 is provided with an eighth switch (Q9) and a tenth switch (Q11), each of which is switched by the same first phase-locked rectification PWM signal (PWM_SR1 (SRA1, SRB1)) The first and third rectifying switching circuits (SRC1 and SRC3), the second phase-locked rectifying PWM signal (PWM_SR2 (SRA2, SRB2)) is switched by a ninth switch (Q9) and an eleventh switch (Q11) each provided Second and fourth rectifying switching circuits (SRC2, SRC4), first and second rectifying switching circuits (SRC1 and SRC2) resonant with the first resonant circuit (RCR1) and third and fourth rectifying switching circuits (SRC3, SRC4) And a second resonant circuit RRC2 that resonates with.

The phase-locked rectification circuit unit 120 adopts a synchronous rectification circuit to increase energy conversion efficiency, and a general rectification circuit uses a diode. If the forward voltage drop of the diode is 0.65 to 1.2 V and the energy transfer period is considered to be a duty of 0.8, the loss of the output diode is a significant part of the overall efficiency. However, in the output section 2 of the AC-DC converter of the present invention, a synchronous rectification circuit is adopted in the output rectification section to improve efficiency by the low impedance RDS (on) path of the eighth to eleventh switches (MOSFETs Q8 to Q11). It is configured to greatly increase.

6 is a detailed circuit diagram of the output current detection unit 140 of the output unit 2.

5 and 6, the output current detection unit 140 is provided with a first amplifier (U1: Op-amp) for control after detecting and amplifying the output current for output current detection, and the first amplifier It comprises a first low-resistance classifier (SH1) that outputs the output of (U1: Op-amp) to DDC_CURR (MCU A / D) of the MCU board constituting the output unit controller 2 '.

Referring again to FIG. 4, the output filter and the voltage detector 150 are provided with a high-frequency circuit including a first inductor L1 and ten to fifteenth capacitors C10 to C15 to generate a high-frequency switching waveform. It is configured to filter with perfect DC power and supply it to the output.

The output voltage detection has two circuits and is composed of the front end (R17, R26, R28, C17) and the rear end (R18, R27, R29, C18) of the second relay (RL1B), which is the output relay, of the front end of the second relay (RL1B). The voltage is output to the DDC_VSEN port of the MCU constituting the output section control section 2, and the voltage of the second stage of the second relay RL1B is output to the VOUT_SEN port of the MCU of the output section control section 2. When connecting for charging of the electric vehicle battery, the input terminal side voltage, which is the voltage before the second relay RL1B, can operate the second relay RL1B when the voltage of the AC-DC converter side is equal to the voltage of the battery. The output capacitors C10 to C15 are thereby protected from overcurrent.

FIG. 7 is a circuit diagram of the second gate driver unit 90 for driving the switching element of the inverter unit 80 in the configuration of the output unit 2, and FIG. 8 is an actiator clamp snubber unit in the configuration of the output unit 2 It is a circuit diagram of the third gate driver unit 110 for driving the switching element of (100), Figure 9 is a fourth gate driver unit for driving the switching element of the phase-locking rectifier circuit 120 of the configuration of the output unit 2 It is a circuit diagram of 130.

The above-described second, third and fourth gate driver unit 90 supplies driving power for driving the output PWM small signal (3.3 V) of the MCU of the output unit control unit 2 to the output unit switches Q1 to Q11. It is configured to use a 12 V power supply. In addition, the second gate driver circuit 90 for driving the switches (, Q1 to Q4) configured in the inverter 80 of FIG. 7 is a second transformer (T2) and a third transformer for isolation from the inverter unit 80 A fourth gate driver unit 130 having (T3) and driving switches Q5 and Q6 configured in the active clamp snubber unit 100 is provided with a fourth and a fourth for insulation with the active clamp snubber unit 100. 5 Transformers (T4, T5) are provided.

10 is a circuit diagram of the output unit control unit 160 in the configuration of the output unit 2.

10, the output unit MCU circuit constituting the output unit control unit 160 generates a total of 8 100 khz PWM signals to generate ZVS (4: PWM_Q1, PWM_Q2.PWM_Q3, PWM_Q4) and synchronous rectification (2: PWM_SR1 , PWM_SR2), and active clamps (two: PWM_CLAMP1, PWM_CLAMP2) are configured to output to the inverter unit 80, the phase-locked rectification circuit unit 120, and the active clamp snubber unit 100.

Specifically, the output unit control unit 160 is the first to fourth PWM signals for switching control of the first to fourth switches (Q1, Q2, Q3, Q3) for the ZVS of the inverter unit 10 Four: PWM_Q1, PWM_Q2.PWM_Q3, PWM_Q4) and switching control of the eighth and ninth switches (Q8 and Q9) and the tenth and eleventh switches (Q10 and Q11) configured in the above-described pseudosynchronous rectifier circuits. Four 2-phase synchronous rectified PWM signals (PWM_SR1, PWM_SR2), first and second clamp PWM signals (PWM_CLAMP1, PWM_CLAMP2) for switching control of the fifth and sixth switches (Q5, Q6) of the active clamp snubber part (100) ) Is configured to control switching and ZVS for DC-DC conversion of the output unit 2 by outputting.

The full-bridge topology of the inverter unit 80 is controlled by phase shift modulation to achieve ZVS by the output unit controller 160 having the above-described configuration, and two switches of the same leg are fixed at 50%. It is made of two complementary signals with a duty cycle and proper dead time, and the two signals that are phase shifted are executed in the control loop 50 kHz.

The voltage control algorithm is controlled based on a simple voltage loop implemented with a traditional PI regulator.

Four LED lamps are prepared to indicate the status, indicating the charging status (three) and the failure status (5).

11 is a circuit configuration diagram of a communication unit that performs communication between the input unit 1 and the output unit 2.

The communication unit having the circuit configuration of FIG. 11 is equipped with a CAN port for external communication, and the CAN communication port is electrically isolated from an external system through PC1 and PC2, and communicates with an input unit MCU board configured in the input unit 10 Also provides electrically isolated communication through PC3 and PC4. CAN communication guarantees the speed of 1Mbps.

12 is a circuit diagram of the bias supply 3 in FIG. 1.

The bias supply unit 3 includes a bias circuit for supplying power, and the bias circuit generates all auxiliary power in the AC-DC converter of the embodiment of the present invention, and + 12V / 0.5A, 3.3V / to the input unit 1 1A, 12V / 0.5A, 3.3V / 1A, and 24V / 0.5A are stably supplied to the output unit 2, and 24V / 0.5A is configured to provide for driving a cooling fan.

The bias circuit is provided with a chip (U4) dedicated to SMPS, and outputs 400 Vdc of the input unit (1) as an input to drive the first transformer (T1), which is an insulation transformer, to produce and supply a desired secondary side voltage.

It should be noted that, although the technical spirit of the present invention described above has been specifically described in a preferred embodiment, the above embodiment is for the purpose of explanation and not of limitation. In addition, those skilled in the art of the present invention will understand that various embodiments are possible within the scope of the technical spirit of the present invention. Therefore, the true technical protection scope of the present invention should be defined by the technical spirit of the appended claims.

Q1 to Q11: first to eleventh switches
BC1 to BC4: 1st to 4th bridge circuits
PWM_Q1 ~ PWM_Q4: 1st to 4th inverter PWM signals
PWM_SR1 (SRA1, SRB1): 1st phase synchronous rectified PWM signal
PWM_SR2 (SRA2, SRB2): Second phase synchronous rectified PWM signal
PWM_CLAMP1: 1st clamp PWM signal
PWM_CLAMP2: second clamp PWM signal

Claims (5)

Input power input unit (1) for correcting the power factor of the AC power to 0.9 to 1 and then rectifying and outputting the DC power;
After receiving the output DC power of the input unit (1), after performing synchronous rectification and active clamping to achieve zero voltage switching, DC-DC is converted to a voltage required for charging the battery and output, and an active clamp snubber circuit is provided. An output section 2 to be said; And
And a bias supply unit 3 for supplying power for driving the input unit 1 and the output unit 2,
The output unit 2 is configured to include a full-bridge circuit for zero voltage switching, and each leg of the bridge circuit is driven by two complementary PWM signals having a fixed 50% duty. An AC-DC converter for charging an electric vehicle battery, comprising an inverter unit 80 having a first current transformer CT1 for detecting a short-circuit current of an output and a full bridge. According to claim 1,
The input unit 1,
An EMC filter unit 10 configured to connect two filters (F1, F2) having different frequency bands to two stages and to be connected to an input rectifier bridge diode of the PFC to mitigate electromagnetic interference;
It has a first relay (RL1A) connected in parallel with a first thermistor (PT1) connected to the AC power input terminal, the internal capacitor by the resistance value of the first thermistor (PT1) to limit the inrush current when the input power input C19 and C20, C6 and C7) to limit the charging current, detect the VBUS voltage, detect that the voltage is normal, and then drive the first relay (RL1A) to limit the inrush current limiting part (15) ;
It is provided with an eleventh capacitor (C11) composed of a full-bridge diode and a pair of parallel-connected capacitors connected in parallel with the full-bridge diode, and rectifies the AC power input from the EMC filter unit 10 to DC power and outputs it. An input rectifying unit 20;
An input voltage current detection unit 30 which detects input AC voltage and dry current and outputs the input voltage to the input unit control unit 70 for reverse flow compensation control;
Includes two parallel boost converters (BC1, BC2) and two current transformers (CT1, CT2) connected to each switch to measure the average inductor current for each leg of the two parallel boost converters (BC1, BC2). , Power factor compensation two-phase boost converter unit 40 that drives the switches of each leg with the same duty cycle, receives AC power filtered from the EMC filter unit 10 through the RECT + port, and rectifies and outputs the DC power; And
High voltage DC bus voltage detection detects with voltage divider resistors (R24, R27, R29, R33, R34, R35) and then DC voltage voltage detection and filter unit outputting to the VBUS + port of the MCU board constituting the input unit controller 70 ( 50) AC-DC converter for charging an electric vehicle battery comprising a. According to claim 2,
The input unit 1,
In order to control the PFC for the power factor compensation two-phase boost converter unit 40, including a phase-locked loop (PLL), calculate the input voltage frequency, amplitude, and ensure synchronization with the input current, duty cycle feed forward (duty cycle) With the introduction of feed-forward control technology, the low total harmonic distortion (THD) and power factor (PF), even when operating in continuous conduction mode (CCM) and discontinuous conduction mode (DCM), range from 0.9 to 1 over the entire operating range. AC-DC converter for charging an electric vehicle battery further comprising; an input unit control unit (70) for controlling the input power of the input unit (1). According to claim 1,
The output unit 2 is
A full-bridge circuit having four first to fourth bridge circuits (BC1 to BC4) each including one of the first to fourth switches Q1, Q2, Q3, and Q4 is provided to perform ZVS switching to perform the input. An inverter unit 80 for converting and outputting DC power output from (1) into AC power;
A second gate driver unit 90 for supplying driving power to the inverter unit 80;
An active clamp snubber part 100 consisting of a clamp network in the phase rectifier rectifier circuit 120, which is an output rectifier, for clamping voltage spikes due to leakage inductance and diode junction capacitance of the first transformer T1;
A third gate driver unit 110 supplying driving power to the active clamp snubber unit 100;
A phase-locked rectifying circuit unit 120 which converts the output AC power of the inverter unit 80 into phase-current and outputs it as a phase-locked current;
A fourth gate driver unit 130 supplying driving power to the phase-locked rectification circuit unit 120;
Output current detection unit having a first low-resistance classifier (SH1) for detecting the current of the output DC power of the phase-locking rectifier circuit 120 and outputting it to DDC_CURR (MCU A / D) of the output unit controller 2 140);
An output filter and a voltage detection unit 150 having a high-frequency circuit including a first inductor L1 and tenth to fifteenth capacitors C10 to C15, filtering the high-frequency switching waveform with DC power and supplying it as an output; And
The first to fourth inverter PWM signals (PWM_Q1, PWM_Q2.PWM_Q3, PWM_Q4) for switching control of the first to fourth switches (Q1, Q2, Q3, Q3) for ZVS of the inverter unit 10 and the First to second phase-locked rectification PWM signals (PWM_SR1 (SRA1, SRA1) for switching control of the eighth and tenth switches Q8 and Q10 and the ninth and eleventh switches Q9 and Q11 configured in the phase-locked rectification circuit unit SRB1), PWM_SR2 (SRA2, SRB2)), first and second clamp PWM signals (PWM_CLAMP1, PWM_CLAMP2) for switching control of the fifth and sixth switches Q5, Q6 of the active clamp snubber part 100 AC-DC converter for charging an electric vehicle battery, comprising: an output unit control unit 160 for controlling switching and ZVS for DC-DC conversion of the output unit 2 by outputting. The method of claim 4,
The inverter unit 80,
Full bridge circuit having four first to fourth bridge circuits (BC1 to BC4) each including one of the first to fourth switches (Q1, Q2, Q3, Q4) and for detecting current in the full bridge circuit The fourth inductor L4 connected to the coupling node a of the first current transformer CT1 and the second and fourth bridge circuits BC2 and BC4 of the full bridge circuit and one end connected to the fourth inductor 14 And the other end includes a first transformer T1 connected to the coupling node b of the first and third bridge circuits BC1 and BC3, and each leg has two fixed 50% Duties. By the complementary PWM signal, the third and fourth switches Q3 and Q4 are driven with a fixed 50% duty cycle, and the pulse width is modulated at the pulse width ends of the upper first and second switches Q1 and Q2. AC-DC converter for electric vehicle battery charging, characterized in that to be driven to perform ZVS.

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