KR101167178B1 - Single Stage Multi-phase Battery Charger - Google Patents

Abstract

A phase difference synchronization signal generator for outputting a plurality of synchronization signals having a predetermined phase difference; A multiphase power converter configured to receive a pulse current and perform power conversion for battery charging by reflecting a power factor correction with the constant phase difference for each path in a single path in multiple paths according to the plurality of synchronization signals; And a feedback signal generator for outputting a feedback signal for controlling the operation of the polyphase power converter.

Description

Single Stage Multi-phase Battery Charger

The present invention relates to a multi-stage battery charger of a single stage, and more particularly, according to a plurality of synchronization signals having a phase difference, power conversion is performed by applying a power factor correction with a predetermined phase difference for each path in a single stage multipath. A single stage multi-phase battery charger for charging batteries.

In general, a battery charger is an essential element in a vehicle powered by a battery, such as an electric vehicle, a fuel cell vehicle, a hybrid vehicle, an electric forklift, and the like.

Conventional chargers have a rectifier 10 for rectifying and converting commercial AC power into direct current, a power factor correction circuit (PFC) circuit 20 to correct the power factor, as shown in FIG. DC-DC converter 30 for converting the required voltage and current, and feedback signal generator 40 for controlling the operation of the DC-DC converter 30 is provided. In addition, an EMI filter may be provided at the front end of the rectifier 10. The feedback signal generator 40 includes circuits for current control and voltage control.

However, the conventional charger is 81% as a whole charger, assuming that the power conversion stage is composed of two stages of the PFC circuit 20 and the DC-DC converter 30 so that the power conversion efficiency of each stage is, for example, 90%. The power conversion efficiency of can be expected. In addition, the PFC 20 and the DC-DC converter 30 have magnetic parts (transformers, inductors), respectively, which have disadvantages of increasing size and weight.

The problem to be solved by the present invention, the PFC circuit and the DC-DC converter is a dual for the power conversion in the conventional charger, the disadvantage of the power loss and the increase of the components and the size of the magnetic components (Transformer, Inductor) such as transformer is large The difficulty in miniaturization is to provide a charger to solve this problem and improve efficiency.

According to an aspect of the present invention, a phase difference synchronization signal generator for outputting a plurality of synchronization signals having a predetermined phase difference; A multiphase power converter configured to perform power conversion for battery charging by applying a pulse rate and reflecting a power factor correction with a predetermined phase difference for each path in a single path in multiple paths according to a plurality of synchronization signals; And a feedback signal generator for outputting a feedback signal for controlling the operation of the polyphase power converter.

Preferably, the multi-phase power converter comprises a transformer for converting a voltage according to the turns ratio for each path; A power factor correction switching controller for outputting a switching control signal reflecting the power factor correction for the pulse current applied to the transformer according to the feedback signal and the synchronization signal; And a switching unit for switching the pulse flow input to the transformer according to the switching control signal.

Preferably, the power factor correction switching control unit, the synchronization input processing unit for receiving a synchronization signal having a phase corresponding to the path; A feedback signal processor receiving the feedback signal; An envelope detection processor for detecting an unmagnetized envelope point of the transformer; A current detection processor detecting current of the transformer and the switching unit; And a switching control signal processor configured to generate a switching control signal reflecting power factor correction based on the synchronization signal, the feedback signal, the non-magnetic envelope point of the transformer, and the current.

The power factor correction switching controller may be implemented as a general-purpose microcontroller having a PFC control IC or firmware.

The phase difference of the plurality of synchronization signals is 360 degrees divided by the number of phases. For example, it may be set to 180 degrees for two phases, 120 degrees for three phases, and 90 degrees for four phases. The number of phases can theoretically be extended.

The single stage multi-phase battery charger may further include a rectifier for outputting a pulse generated at the secondary side of the transformer to a direct current.

Preferably, the single stage multi-phase battery charger may further include a smoothing unit for smoothing the converted direct current. Preferably, the feedback signal generator may include at least one of a voltage feedback circuit or a current feedback circuit connected to an output terminal of the polyphase power converter to generate the feedback signal.

According to the present invention, the conventional PFC circuit and the DC-DC converter circuit are processed in one circuit to solve power conversion in a single stage. As a result, the power conversion transformer is integrated with a conventional PFC transformer (or inductor) and a DC-DC converter into one unit, which can significantly reduce the overall size and weight of the charger and improve the overall power conversion efficiency.

1 is a view for explaining a conventional charger.
2 is a block diagram illustrating a single-stage four-phase battery charger according to an embodiment of the present invention.
3 is a detailed circuit diagram of a single-stage four-phase battery charger according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram illustrating a single-stage four-phase battery charger according to an embodiment of the present invention.

2, the single-stage four-phase battery charger according to an embodiment of the present invention, the power supply unit 100, the multi-phase power converter 200, the phase difference synchronization signal generator 300, rectification smoothing unit 400, the feedback signal generator 500 may be included.

The power supply unit 100 receives AC power, converts the AC power into a pulse current, and provides the same to the multiphase power converter 200.

The power supply unit 100 includes a filter unit 110, a rectifier unit 120, a primary auxiliary power unit 130, and a secondary auxiliary power unit 140.

The filter unit 110 is a single-phase 85V ~ 265V 45Hz ~ 65Hz when AC power is introduced, the L (C) low pass filter of the capacitor and the inductor (inductor) inside the filter unit 110 to the commercial AC power supply Remove the high frequency noise that flows in together and make sure that the noise generated inside the equipment is not radiated to the outside.

The rectifier 120 is connected to the filter unit 110 and rectifies the commercial AC power from which noise is removed by the filter unit 110 to output a pulse.

The primary auxiliary power supply unit 130 supplies auxiliary power for supplying initial power required for initial startup of the polyphase power converter 200. The secondary auxiliary power supply 140 supplies the secondary power.

The polyphase power converter 200 receives a pulse current and performs power conversion for charging the battery by reflecting power factor correction with a predetermined phase difference for each path in the multipath according to the plurality of synchronization signals.

The phase difference synchronization signal generator 300 outputs a plurality of synchronization signals having a predetermined phase difference and provides the same to the polyphase power converter 200. The phase difference of the plurality of synchronization signals is 360 degrees divided by the number of phases. For example, two phases may be set to 180 degrees, three phases to 120 degrees, and four phases to 90 degrees. However, the present invention is not limited to this and can be extended as much. The rectification smoothing unit 400 rectifies and smoothes the power converted by the polyphase power converter 200. On the other hand, when the pulse width is overlapped due to the increase in the number of phases, a stable operation may be possible without having the smoothing part of the rectifying smoothing part 400.

The feedback signal generator 500 outputs a feedback signal for controlling the operation of the polyphase power converter 200.

3 is a detailed circuit diagram of a single stage multi-phase battery charger according to an embodiment of the present invention.

Referring to FIG. 3, a single-stage multiphase battery charger according to an exemplary embodiment of the present invention includes a filter unit 110, a rectifier unit 120, a primary auxiliary power supply unit 130, and a secondary auxiliary power supply unit 140. A power supply unit 100 is provided.

The primary auxiliary power supply 130 and the secondary auxiliary power supply 140 include a first phase power converter 210, a second phase power converter 220, a third phase power converter 230, and a fourth phase. It is connected to the polyphase power converter 200 including the power converter 240.

A phase difference synchronization signal generator 300 for outputting synchronization signals having different phases is connected to an input terminal of the polyphase power converter 200.

The rectifying smoother 400 is provided at the output terminal of the polyphase power converter 200 to rectify and smooth the output of the polyphase power converter 200. The battery is connected to the output terminal of the rectifying smoother 400.

In addition, the output terminal of the rectifying smoother 400 detects an output voltage or current of the rectifying smoother 400, and a feedback signal generator 500 for outputting a feedback control signal to the polyphase power converter 200 is connected. have.

The filter unit 110 may be formed of an EMI line filter. The filter unit 110 may prevent an electromagnetic wave generated from the inside of the circuit from being radiated to the outside, and block an electromagnetic wave from the outside from flowing into the circuit. Play a role.

A fuse F1 for safety is connected to the input terminal of the filter unit 110. In addition, a varistor RV1 is connected to bypass the impulsive overvoltage input from the AC power input through the AC power input terminal to protect the circuit at the rear end and to cut off the fuse at the front end when the overvoltage persists.

The rectifier 120 includes a bridge diode BD1 connected to an output terminal of the filter unit 110, and a capacitor C1 is connected in parallel to an output terminal of the bridge diode BD1. The bridge diode BD1 converts alternating current into pulse current. Capacitor C1 may be a small capacity film capacitor, for example, and serves to cancel electrical noise that may be incorporated into the pulse.

The primary auxiliary power supply unit 130 and the secondary auxiliary power supply unit 140 are configured in two systems for insulation of the input (primary side: input power) and the output (secondary side: output storage battery). The primary auxiliary power supply unit 130 is supplied from the auxiliary winding of the first transformer T1, which is one of four phases, and includes a resistor R17, a diode D7, and a capacitor C4. Secondary auxiliary power supply 140 is composed of a diode (D8) and a capacitor (C3). At this time, the resistor R16 supplies a starting current. All primary power is supplied to the VCC from the primary auxiliary power supply 130, all secondary power is supplied to the VCC1 from the secondary auxiliary power supply 140. The auxiliary winding for the power supply may be drawn out from any one of the first transformer T1, the second transformer T2, the third transformer T3, and the fourth transformer T4.

The multiphase power converter 200 includes a first phase power converter 210, a second phase power converter 220, a third phase power converter 230, and a fourth phase power converter 240. It is composed.

Each of the phase power converters 210, 220, 230, and 240 forms a multipath. Accordingly, each phase power converter 210, 220, 230, and 240 for each path may include a transformer, a power factor correction switching controller, and a switching unit, respectively.

That is, the first phase power converter 210 may include a first transformer T1, a first power factor correction switching controller 211, and a first switch Q1.

The first phase power converter 210 receives pulse current from the rectifier 120 according to the PWM signal and the turns ratio of the first transformer T1 to perform power conversion for battery charging. The first power factor correction switching controller 211 outputs a switching control signal reflecting the power factor correction for the pulse current applied to the first transformer T1 according to the feedback signal and the synchronization signal input from the phase difference synchronization signal generator 130. . The first switching unit Q1 switches the pulse flow input to the first transformer T1 according to the switching control signal of the first power factor correcting switching control unit 211.

Similarly, the second phase power converter 220 may include a second transformer T2, a second power factor correction switching controller 221, and a second switch Q2.

The second phase power converter 220 receives the pulse current from the rectifier 120 according to the PWM signal and the turns ratio of the second transformer T2 and performs power conversion for battery charging. The second power factor correction switching controller 221 outputs a switching control signal reflecting the power factor correction for the pulse current applied to the second transformer T2 according to the feedback signal and the synchronization signal input from the phase difference synchronization signal generator 130. . The second switching unit Q2 switches the pulse current input to the second transformer T2 according to the switching control signal of the second power factor correcting switching controller 221.

Similarly, the third phase power converter 230 may include a third transformer T3, a third power factor correcting switching controller 231, and a third switch Q3.

The third phase power converter 230 converts the pulse current input from the rectifier 120 into power for battery charging according to the PWM signal and the turns ratio of the third transformer T3. The third power factor correction switching controller 231 performs a power factor correction for pulses input from the rectifier 120 applied to the third transformer T3 according to the feedback signal and the synchronization signal input from the phase difference synchronization signal generator 130. The reflected switching control signal is output. The third switching unit Q3 switches the pulse flow input to the third transformer T3 according to the switching control signal of the third power factor correcting switching control unit 231.

Similarly, the fourth phase power converter 240 may include a fourth transformer T4, a fourth power factor correcting switching controller 241, and a fourth switch Q4.

The fourth phase power converter 240 converts the pulse current input from the rectifier 120 into power for battery charging according to the PWM signal and the turns ratio of the fourth transformer T4. The fourth power factor correction switching controller 241 performs power factor correction for pulses inputted from the rectifying unit 120 applied to the fourth transformer T4 according to the synchronization signal input from the feedback signal and the phase difference synchronization signal generator 130. The reflected switching control signal is output. The fourth switching unit Q4 switches the pulse current input to the fourth transformer T4 according to the switching control signal of the fourth power factor correcting switching control unit 241.

The phase generator 300 may generate a sync signal corresponding to a desired number of phases and provide it to the polyphase power converter 200. The phase difference of each phase is a value obtained by dividing 360 degrees by the number of phases and supplying the phase difference to each stage. That is, a phase difference of 180 degrees for two phases, 120 degrees for three phases, and 90 degrees for four phases is required.

The phase difference synchronization signal generator 300 generates four synchronization signals having a phase difference of 90 degrees, for example, as the polyphase power converter 200 is implemented in a four phase manner. The phase difference synchronizing signal generator 300 may generate each of the generated synchronization signals from the first power factor correction switching controller 211, the second power factor correction switching controller 221, the third power factor correction switching controller 231, and the fourth power factor correction. It supplies to the synchronous input processing part of the switching control part 241.

The first power factor correction switching controller 211, the second power factor correction switching controller 221, the third power factor correction switching controller 231, the fourth power factor correction switching controller 241, and the phase difference synchronization signal generator 300 For example, the firmware may be implemented as a PFC controller IC or a general purpose microcontroller with embedded firmware.

PFC controller ICs can be in either Discontinuous Conduction Mode (DCM) or Continuous Conduction Mode (CCM). The first power factor correction switching control unit 211, the second power factor correction switching control unit 221, the third power factor correction switching control unit 231, and the fourth power factor correction switching control unit 241 are respectively a synchronous input processor, a feedback signal processor, And an envelope detecting processor, a current detecting processor, and a switching control signal processor. The synchronization input processor, the feedback signal processor, the envelope detection processor, the current detection processor, and the switching control signal processor may be implemented in hardware or firmware.

The synchronization input processor performs a function of receiving a synchronization signal having a phase corresponding to a corresponding path. For this purpose, each power factor correction switching controller is provided with a synchronization input terminal.

The feedback signal processor performs a function of receiving a feedback signal from the feedback signal generator 500. For this purpose, each power factor correction switching controller is provided with a feedback signal input terminal. The feedback signal processor receives a feedback of the voltage or current of the output, and may receive a signal through a general purpose photo coupler integrating an LED and a photo transistor for isolation.

The envelope detection processor performs a function of detecting a non-magnetic envelope point of each transformer. For this purpose, each power factor correction switching controller is provided with an envelope current detection terminal (ZCD: Zero Current Detector, demagnetization sensing input). The resistors R5, R6, R7 and R8 are connected to the envelope detection terminals.

The current detection processor performs a function of detecting a current flowing in the primary side of each transformer and a current of each switching unit. For this purpose, each power factor correcting switching controller is provided with a current detection terminal. Each current detection terminal receives a voltage proportional to the current generated in the resistors R1, R2, R3, and R4. In one embodiment of the present invention has been described for the detection of current by the method by the resistors (R1, R2, R3, R4), in addition to using a current transformer (CT), coil and Hall (Hall) The device can also be used to detect current.

The switching control signal processor generates a switching control signal reflecting the power factor correction based on the synchronization signal, the feedback signal, the non-magnetic envelope point, and the current. For this purpose, each power factor correction switching controller includes a switching control signal output terminal. do.

Each switching control signal output terminal is PWM (Pulse Width Modulation) for driving each switching unit Q1, Q2, Q3, Q4 to each switching unit Q1, Q2, Q3, Q4 (e.g., gate terminal of the FET). The signal can be output as a switching control signal. In this case, the switching control signal processor may include a component such as a buffer or a driver in order to increase driving capability and speed.

The power factor correction switching controllers 211, 221, 231, and 241 and the phase difference synchronizing signal generator 130 may be simply implemented by configuring firmware in a microprocessor unit (MPU).

The rectifying smoother 400 may include rectifying diodes D1, D2, D3, and D4 that function as rectifiers, and a capacitor C2 that functions as a smoothing part.

The diodes D1, D2, D3, and D4 of the rectifying smoother 400 may have a secondary side of the first transformer T1, the second transformer T2, the third transformer T3, and the fourth transformer T4. It is connected to the secondary side of each transformer (T1, T2, T3, T4) to rectify the generated pulse. Each of the diodes D1, D2, D3, and D4 rectifies power having a phase difference of 90 degrees. The signal rectified by these diodes D1, D2, D3, D4 is smoothed by the capacitor C2. At this time, the capacity of the capacitor (C2) has a phase difference of 90 degrees each power of each of the transformers (T1, T2, T3, T4) theoretically 1/4 of the capacity compared to a single phase by one transformer Do.

The feedback signal generator 500 includes a resistor RS1 connected to the first output of the rectifying smoother 400. The resistor RS1 generates a voltage proportional to the output current to generate a current feedback signal C_NF. In one embodiment of the present invention has been described for detecting the current by the method by the resistor (RS1), in addition to the current by using a current transformer (CT), or using a coil and a Hall (Hall) element It can also be detected.

On the other hand, the resistor R12 and the resistor R13 are connected to the second output of the rectifying smoother 400 to form a voltage divider circuit. The resistor R12 and the resistor R13 divide the output voltage of the rectifying smoother 400 to generate a voltage feedback signal V_NF. The feedback signal generator 500 includes a sink regulator including a resistor R8 and a reference voltage source U2. The sink regulator generates a reference voltage. For example, when the reference voltage source U2 is used as the TL431 device, a stable voltage of 2.5V can be generated. In addition, any reference voltage source may be used as long as it generates a precise voltage.

The feedback signal generator 500 may include a voltage feedback circuit and a current feedback circuit.

The voltage feedback circuit may include a first operational amplifier U1A, a diode D5, a capacitor C6, and a resistor R15. The capacitor C6 and the resistor R15 may be configured to prevent oscillation of the voltage feedback circuit. It is provided with.

The current feedback circuit may include a second operational amplifier U1B, a diode D6, a capacitor C5, and a resistor R14. The capacitor C5 and the resistor R14 may be used to prevent oscillation of the current feedback circuit. It is provided.

The voltage feedback circuit receives the reference voltage REF at the non-inverting terminal of the first operational amplifier U1A, and inverts the output voltage from the second output terminal of the rectifying smoother 400 to the inverting terminal 12. The voltage feedback signal V_NF divided by 13 is input, and the voltage feedback signal V_NF is compared with the reference voltage REF.

The current feedback circuit receives the current feedback signal C_NF at the inverting terminal of the second operational amplifier U1B, and divides the reference voltage REF into the resistor R10 and the resistor R11 at the noninverting terminal. The C_Ref voltage is input and the current feedback signal C_NF is compared with the reference current C_Ref voltage signal.

The voltage feedback circuit and the current feedback circuit operate to select a minimum value among the values output at the output terminals of the respective operational amplifiers U1A and U1B. That is, neither voltage nor current exceeds the set limit.

The voltage feedback circuit and the current feedback circuit are connected in parallel with each other and connected to the photo coupler ISO1 through a resistor R16. The resistor R16 serves to limit the current and widen the linear region.

The LED of the photocoupler ISO1 is driven by the minimum value selected in the voltage feedback circuit and the current feedback circuit.

For example, when the current feedback signal C_NF input to the inverting terminal of the second operational amplifier U1B of the current feedback circuit is higher than the current reference voltage C_Ref input to the non-inverting terminal, that is, the output current is larger than the set value. In the case of flowing, since the output becomes negative and the output terminal voltage of the second operational amplifier decreases, the current flowing through the diode D6 increases, and the LED of the photo coupler ISO1 becomes bright. This is because a large current flows through the photo coupler ISO1. When a large amount of current flows through the photo transistor of the photo coupler ISO1, the photo transistor has a low equivalent resistance, which increases the current flowing to the feedback input terminal of each power factor correcting switching controller 211, 221, 231, 241. The voltage applied is lowered. Then, the switching control signal processing unit of each power factor correcting switching control unit 211, 221, 231, 241 adjusts the PWM width small so as to lower the voltage by the increased amount, thereby switching each switching unit Q1, Q2, Q3, Q4. ) Thus, both voltage and current can be controlled.

In the single stage multi-phase battery charger according to the present invention, the conventional PFC circuit and the DC-DC converter circuit are processed in one circuit to solve power conversion in a single stage. As a result, the power conversion transformer is integrated into one conventional PFC transformer and one DC-DC converter, resulting in a significant reduction in size and weight, and an increase in power conversion efficiency (90% at the same technical level).

Conventional chargers can not reduce the volume of the magnetic components by performing power conversion to a single phase, but can be miniaturized by reducing the size of the overall transformer by a multi-phase (Multi Phase) design according to an embodiment of the present invention. The table below shows the volume reduction rate according to the multiphase design.

Tops WaAc Cm ^ 4 Volume reduction rate One 23.228 0 2 5.807 32 3 2.581 47 4 1.452 51

Here, Wa denotes the window area of the core in the transformer, and Ac denotes the effective cross-sectional area of the core in the transformer. As shown in Table 1, the principle of reducing the volume of the transformer by the multiphase design is as follows.

가 된다. 여기에서 E는 에너지(전력)이고, L은 코일의 인덕턴스이고 I는 코일에 흐르는 전류이다. 한편, 2 상에서 필요한 에너지는 단일상과 동일하게 보면

가 된다. 즉 상이 증가됨에 따라 필요한 인덕턴스가 현저하게 줄어들게 되기 때문에 결과적으로 트랜스포머의 부피가 저감된다.In other words, the energy needed for a single phase

. Where E is energy (power), L is the inductance of the coil, and I is the current flowing through the coil. On the other hand, the energy required for two phases is the same as that of a single phase.

. In other words, as the phase increases, the required inductance is significantly reduced, resulting in a reduced transformer volume.

Embodiment of the present invention is only one embodiment, of course, many modifications and variations of the components of the present invention without departing from the gist of the present invention, of course, the present invention is not limited to the embodiment. . For example, in the embodiment of the present invention, the multi-phase power converter is implemented in four phases, but the present invention is not limited thereto, and the implementation may be modified to any number of two-phase, three-phase, five-phase, six-phase or more. It is possible.

110: filter unit 120: rectifying unit
130: primary auxiliary power supply 140: secondary auxiliary power supply
200: polyphase power converter 210: first phase power converter
211: first power factor correction switching controller 220: second phase power converter
221: second power factor correction switching controller 230: third phase power converter
231: third power factor correction switching controller 240: fourth phase power converter
241: fourth power factor correction switching controller 300: phase difference synchronization signal generator
400: rectification smoother 500: feedback signal generator

Claims (7)

A phase difference synchronization signal generator for outputting a plurality of synchronization signals having a predetermined phase difference;
A multi-phase power converter configured to receive a pulse current and perform power conversion for battery charging by reflecting a power factor correction for each path in the single path multipath according to the plurality of synchronization signals; And
It includes a feedback signal generator for outputting a feedback signal for controlling the operation of the multi-phase power converter,
The polyphase power converter is for each path,
A transformer for converting the voltage according to the turns ratio;
A power factor correction switching controller for outputting a switching control signal reflecting the power factor correction for the pulse current applied to the transformer according to the feedback signal and the synchronization signal; And
And a switching unit for switching the pulse flow input to the transformer according to the switching control signal.
The power factor correction switching control unit,
A synchronization input processor configured to receive a synchronization signal having a phase corresponding to a corresponding path;
A feedback signal processor receiving the feedback signal;
An envelope detection processor for detecting an unmagnetized envelope point of the transformer;
A current detection processor detecting current of the transformer and the switching unit; And
And a switching control signal processor configured to generate a switching control signal reflecting power factor correction based on the synchronization signal, the feedback signal, the non-magnetic envelope point, and the current. delete delete The method according to claim 1,
The power factor correction switching control unit is a multi-stage battery charger, characterized in that implemented as a general-purpose microcontroller with a built-in PFC control IC or firmware. The method according to claim 1,
Single stage multi-phase battery charger further comprises a rectifier for outputting a direct current pulse generated on the secondary side of the transformer. The method according to claim 5,
Single stage multi-phase battery charger further comprises a smoothing unit for smoothing the converted direct current. The method according to claim 1,
And the feedback signal generator comprises at least one of a voltage feedback circuit and a current feedback circuit connected to an output terminal of the polyphase power converter to generate the feedback signal.

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