TWI587617B - Two - way power converter and its operation method - Google Patents

Description

Bidirectional power converter and its operating method

The invention relates to a power converter; in particular to a two-way power converter and method of operation thereof.

Under the promise of people to stop "climate crime" and implement energy conservation and carbon reduction, the world's first legally binding greenhouse gas reduction agreement "Paris Agreement" was passed on December 12, 2015, a total of 195 The country has reached a global climate change agreement and has become a historic reform of energy policies in various countries. According to the International Energy Agency (IEA) assessment, according to the targets set out in the agreement, by 2030, countries will invest up to 16.5 trillion US dollars in renewable energy and energy efficiency. This means that governments must encourage the production of green energy, reduce the support for fossil fuels such as oil, and even affect the transportation industry.

At present, among the many green energy sources, the application of fuel cells is particularly concerned, and the following is an example of the application of a fuel cell vehicle. The working principle of the fuel cell is that hydrogen is used as a fuel, and oxygen is electrochemically reacted to generate electric energy through the proton exchange membrane. The advantages include zero pollution, high efficiency, low noise, low vibration and long life, and are suitable for It replaces the choice of traditional steam and diesel engines with high pollution and low efficiency. In particular, fuel cell vehicles have the advantage of fast fuel replenishment compared with pure electric vehicles. As far as electric vehicles produced by American electric car dealer Tesla are concerned, their electric vehicles are fully charged. It takes tens of minutes to several hours, and it takes only a few minutes for the fuel cell vehicle to complete the fuel replenishment. give. Because of this, fuel cell vehicles have become the key technology that the United States, Japan, Europe and other countries are vying to develop in recent years, and have become the products of reward and promotion in these countries.

At present, the fuel cell generators mainly have three problems, such as cold start, slow dynamic response and brake feedback energy storage, which need to be solved. Further exploration of its cause is mainly affected by the polarization loss at the input end of the fuel cell, resulting in unstable DC voltage at the output end of the fuel cell and slow response. In order to adapt the fuel cell electric vehicle to various environments and more driving operating conditions, the powertrain configuration must include a vehicle-mounted auxiliary energy storage component such as a battery pack or an ultracapacitor. Therefore, when the vehicle operates in a state of low speed, low load or urban driving, the vehicle power is mainly provided by the battery; when the vehicle operates in a state of high speed, high load and rapid deceleration, the ultracapacitor can provide the emergency power demand and assist the recovery brake. energy.

In recent years, many experts and scholars have continuously raised relevant research topics on the integration of power converters, drives, energy management and charge and discharge technologies in electric vehicle systems. Among them, as far as the published literature is concerned, it is known that a general DC/DC power converter can only transfer energy in one direction, and if there is a need to reversely recover energy, such as a charger, an uninterruptible power system, and a motor brake back charge application, Another set of DC/DC power converters is needed to match. However, the addition of a set of power converters will increase the number and size of components and increase the cost. Therefore, in recent years, many experts and scholars have successively invested in two-way power converter research.

Bidirectional power converters can be divided into isolated (isolated) and non-isolated (Nonisolated). The advantages of isolated converters are high voltage transformers, electrical isolation, and wide input through the transformer turns ratio design. / Output operation range, etc. However, the leakage inductance and distributed capacitance of the high-voltage transformer will make the voltage and current surge become larger, which will affect the reliability of the whole circuit. In addition, the transformer also causes many problems such as loss of efficiency, difficulty in heat dissipation, and volume. In response to the above problems, non-isolated bidirectional converters are widely used in high Power / high efficiency occasions. Among them, the simplest non-isolated bidirectional converter is a half-bridge step-up/step-down converter, and the working state is divided into a buck and a boost mode, which are respectively used for charging and discharging the electric vehicle battery pack. The half-bridge converter has a simple architecture and the lowest cost. However, when operating in the boost mode, the DC bus voltage is easily reduced due to parasitic effects, and the converter efficiency is greatly reduced as the switching duty cycle increases. On the other hand, the inductor current ripple is large and limited by the gain conversion ratio of the high and low voltage sides. The design of the battery pack and the DC bus voltage is not suitable for low voltage applications. Therefore, in order to further reduce the inductor current ripple and improve the efficiency, a two-phase or multi-phase interleaved bidirectional power converter is proposed in the literature. However, the interleaving operation through the converter can achieve low chopping requirements, but with The larger the voltage difference between the input and output of the converter, the non-ideal working condition of the duty cycle of the switch is too large or too low.

Therefore, the existing two-way power converter still has problems such as high system control complexity, high cost, easy operation in a non-ideal working state, and low conversion efficiency, and needs to be improved.

In view of this, the object of the present invention is to provide a bidirectional power converter that can meet the application range and development trend of the electric vehicle industry, and can achieve the purpose of suppressing peak load and improving conversion efficiency, thereby achieving energy saving and carbon reduction.

In order to achieve the above objective, the present invention provides a bidirectional power converter for coupling between a battery, an ultracapacitor, and a driver; the battery has a positive end and a negative end; the driver has a constant current confluence And the DC bus bar has a positive end and a negative end; the bidirectional power converter includes: a first switch having a first end and a second end, and the second end of the first switch The positive terminal of the battery is electrically connected; a second The switch has a first end and a second end, and the first end of the second switch is electrically connected to the positive end of the DC bus, the second end of the second switch and the first end of the first switch The third switch has a first end and a second end, and the second end of the third switch is electrically connected to the negative end of the battery and the negative end of the DC bus. The third switch is connected in parallel with the super capacitor; a fourth switch has a first end and a second end, and the first end of the fourth switch is electrically connected to the second end of the first switch, the first The second end of the four switch is electrically connected to the negative end of the battery and the negative end of the DC bus; the fifth switch has a first end and a second end, and the first end of the fifth switch The second end of the first switch is electrically connected to the first end of the sixth switch, and the first end of the sixth switch is electrically connected to the first end of the third switch. a second end of the six switch is electrically connected to the second end of the fifth switch; and a clamp capacitor, one end and the second open A second terminal electrically connected to the other end connected to the first terminal of the third switch.

According to the above concept, a filter inductor is further included, one end of which is electrically connected to the second end of the first switch, and the other end is electrically connected to the first end of the fifth switch and the positive end of the battery.

According to the above concept, when the bidirectional power converter is operated in a first mode, the fifth switch and the sixth switch are controlled to be in an off state, and the third switch and the fourth are alternately switched. The switch performs switching control, and performs switching control on the first switch and the second switch in a synchronous rectification manner; thereby causing the battery and the ultracapacitor to discharge the DC bus bar.

According to the above concept, the duty cycle of the third switch and the fourth switch is greater than 50%.

According to the above concept, the third switch and the fourth switch are controlled by an interlaced pulse width modulation signal.

According to the above concept, when the bidirectional power converter operates in a second mode, the fifth switch and the sixth switch are controlled to be in an off state, and the first switch and the second are alternately switched. The switch performs switching control to switch the third switch and the fourth switch in a synchronous rectification manner; thereby causing the DC bus to charge the battery and the ultracapacitor.

According to the above concept, the duty cycle of the first switch and the second switch is less than 50%.

According to the above concept, the first switch and the second switch are controlled by an interlaced pulse width modulation signal.

According to the above concept, when the bidirectional power converter is operated in a third mode, the first switch, the second switch, the fourth switch, and the sixth switch are controlled to be in an off state, and are adjusted by a pulse width. The variable signal drives the fifth switch, and the third switch performs synchronous rectification, so that the battery is discharged and stored in the ultracapacitor.

According to the above concept, when the bidirectional power converter operates in a fourth mode, the first switch, the second switch, the fourth switch, and the fifth switch are controlled to be in an off state, and are modulated by a pulse width. The variable signal drives the third switch, and the sixth switch performs synchronous rectification, so that the ultracapacitor is energy-released and stored in the battery.

In order to achieve the above object, the present invention further provides an operation method comprising the steps of: A: detecting an operating state of the driver; B, performing one of the following steps on the bidirectional power converter according to an operating state of the driver; : B1, when the driver is activated, upgraded or accelerated, the bidirectional power converter operates in a first mode, and controls the fifth switch and the sixth switch to be in an off state, and is in an interleaved manner. The third switch and the fourth switch perform switching control, and perform switching control on the first switch and the second switch in a synchronous rectification manner; thereby, the battery and the ultracapacitor supply energy to the DC confluence a row; B2, when the driver is under load or deceleration, the bidirectional power converter operates in a second mode, and controls the fifth switch and the sixth switch to be in an off state, and is switched in an interleaved manner The first switch and the second switch perform switching control to switch the third switch and the fourth switch in a synchronous rectification manner; thereby recovering the energy of the DC bus and recharging the battery and the ultracapacitor.

According to the above concept, when the bidirectional power converter is operated in a third mode, the first switch, the second switch, the fourth switch, and the sixth switch are controlled to be in an off state, and are adjusted by a pulse width. The variable signal drives the fifth switch, and the third switch performs synchronous rectification, so that the battery is discharged and stored in the ultracapacitor.

According to the above concept, when the bidirectional power converter operates in a fourth mode, the first switch, the second switch, the fourth switch, and the fifth switch are controlled to be in an off state, and are modulated by a pulse width. The variable signal drives the third switch, and the sixth switch performs synchronous rectification, so that the ultracapacitor is energy-released and stored in the battery.

The invention has the effects of effectively reducing the chopping current of the high-voltage side DC busbar, achieving the effects of low chopping, gain/boost converter gain enhancement, and the management and distribution of dual-electric energy.

〔this invention〕

100‧‧‧Bidirectional power converter

10‧‧‧Battery

20‧‧‧DC busbar

30‧‧‧Supercapacitors

Q ₁ ‧‧‧First switch

Q ₂ ‧‧‧First switch

Q ₃ ‧‧‧Second switch

Q ₄ ‧‧‧fourth switch

Q ₅ ‧‧‧ fifth switch

Q ₆ ‧‧‧ sixth switch

Q _BT ‧‧‧ switch

Q _UC ‧‧‧ switch

C _B ‧‧‧Clamp Capacitor

L ₁ ‧‧‧Filter inductor

L ₂ ‧‧‧Filter inductor

V _BT ‧‧‧voltage source

V _UC ‧‧‧voltage source

V _H ‧‧‧ voltage

V _{gs1 ‧‧‧gate} source voltage of the first switch

V _{gs2 ‧‧‧gate} source voltage of the second switch

V _{gs3 ‧‧‧gate} source voltage of the third switch

V _{gs4 ‧‧‧gate} source voltage of the fourth switch

V _{gs5 ‧‧‧gate} switch terminal voltage

1 is an equivalent circuit diagram of a bidirectional power converter according to a first embodiment of the present invention.

2 is an equivalent circuit diagram of the bidirectional power converter of the above embodiment operating in the first mode (forward boost mode).

3 is a diagram showing driving waveforms of the first to fourth switches, and current and output voltage waveforms of the battery/capacitor when the bidirectional power converter of the above embodiment operates in the first mode.

4A and 4B are diagrams showing the relationship between the conversion ratios of the DC bus voltages to different input energy sources when the bidirectional power converter of the above embodiment operates in the first mode.

Fig. 5 is an equivalent circuit diagram of the dual mode power supply operating in the second mode (reverse buck mode) of the above embodiment.

6 is a diagram showing driving waveforms of the first to fourth switches, and current and output voltage waveforms of the battery/capacitor when the bidirectional power converter of the above embodiment operates in the second mode.

7A and 7B are diagrams showing the conversion ratio of the DC bus voltage to different input energy sources when the bidirectional power converter of the above embodiment operates in the second mode.

Fig. 8 is an equivalent circuit diagram when the bidirectional power converter of the above embodiment operates in the third mode or the fourth mode.

Fig. 9 is a waveform diagram showing the driving waveform of the fifth switch and the waveform of the storage of the battery to the capacitor when the bidirectional power converter of the above embodiment operates in the third mode.

Fig. 10 is a waveform diagram showing the driving waveform of the third switch when the bidirectional power converter of the above embodiment operates in the fourth mode, and the waveform of the capacitor discharging energy to the battery.

In order to explain the present invention more clearly, some embodiments are described in detail with reference to the drawings. Referring to FIG. 1 , a bidirectional power converter 100 according to a first embodiment of the present invention is coupled between a battery 10 , an ultracapacitor 30 , and a driver . The battery 10 has a positive end and a Negative end, the driver has a constant flow bus 20, and the straight The current bus bar 20 has a positive terminal and a negative terminal. In the embodiment, the DC bus bar 20 has a DC 600-700V standard, but is not limited thereto. Thereby, the electrical energy of the battery 10 and the ultracapacitor 30 can be transmitted to the driver through the bidirectional power converter 100 for the driver to operate.

The battery 10 can be selected from a Lithium Iron Phosphate Oxide (LFPO) battery, a Lithium iron phosphate (LFP) battery, a ternary polymer lithium battery, a lead-acid battery, etc., but not limit. In the present embodiment, the battery 10 is a lithium iron oxide phosphorus battery, which has the advantages of low cost, high conductivity and recycling times of the positive electrode material, low self-discharge rate, and environmental protection. The shape is light and short, and can withstand high voltage and high temperature, so it is specially adapted to the power demand of the drive. In addition, for convenience of description, the battery 10 used in this embodiment is exemplified by a single piece, and its specification is DC 144V/15AH, but in other practical implementations, the number of the battery is not limited to a single one, and may also be According to the actual working voltage and current demand, multiple batteries in parallel or in series are selected for use.

The driver generally refers to a driver of various types of electrical equipment, for example, it may be a motor driver for driving the motor of the vehicle, and the carrier may be a car, a locomotive, a ship, an aircraft, etc., and For convenience of description, the driver of the present embodiment is an electric vehicle motor driver that drives the engine of the electric vehicle, but it is not limited thereto in other practical implementations.

The bidirectional power converter 100 includes a first switch Q ₁ , a second switch Q ₂ , a third switch Q ₃ , a fourth switch Q ₄ , a fifth switch Q ₅ , a sixth switch Q ₆ , and a The filter inductor L ₁ , a filter inductor L ₂ and a clamp capacitor C _B . In the present embodiment, preferably, the first to sixth switches Q ₁ to Q ₆ are Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs). In addition, in other applications, other types of switches and voltage control components may be selected depending on the use requirements, and are not limited to the above MOSFETs.

The circuit architecture of the bidirectional power converter 100 of the present invention will be described hereinafter, wherein:

The battery 10 can be equivalent to a voltage source V _BT and a switch Q _BT . A first positive terminal of the voltage source V _BT of Q _BT switch is connected with the negative electrode of the voltage source V _BT constituting the negative terminal of the battery; a second terminal of the switch Q _BT constituting the positive terminal of the battery.

The first switch Q ₁ has a first end and a second end, and the second end of the first switch Q ₁ is electrically connected to the positive end of the battery 10 .

The second switch Q ₂ has a first end and a second end, and the first end of the second switch Q ₂ is electrically connected to the positive end of the DC bus 20 , and the second switch Q ₂ is The two ends are electrically connected to the first end of the first switch Q ₁ .

The third switch Q ₃ has a first end and a second end, and the second end of the third switch Q ₃ is electrically connected to the negative end of the battery 10 and the negative end of the DC bus 20 .

The fourth switch Q ₄ has a first end and a second end, and the first end of the fourth switch Q ₄ is electrically connected to the second end of the first switch Q ₁ , and the fourth switch Q ₄ The second end is electrically connected to the negative end of the battery 10 and the negative end of the DC bus bar 20.

The fifth switch Q ₅ has a first end and a second end, and the first end of the fifth switch Q ₅ is electrically connected to the second end of the first switch Q ₁ .

The sixth switch Q ₆ has a first end and a second end, and the first end of the sixth switch Q ₆ is electrically connected to the first end of the third switch Q ₃ , and the sixth switch Q ₆ The second end is electrically connected to the second end of the fifth switch Q ₅ .

The super capacitor lines 30 and the third switch Q ₃ in parallel, which in the present embodiment, the specifications of DC 72V / 500F, but on other practical embodiments, is not limited thereto. The capacitor 30 can be equivalent to a voltage source V _UC , a switch Q _UC and a filter inductor L ₂ . The negative pole of the voltage source V _UC is electrically connected to the negative terminal of the battery, and the positive pole and the switch of the voltage source V _UC a first terminal electrically connected to _{the UC} Q; Q of the switch a second end connected to _{the UC} L ₂ One end of the filter inductor; L ₂ the other end of the filter inductor with a first terminal of the third switch Q ₃ is electrically connection.

In this embodiment, the first ends of the first to sixth switches Q ₁ -Q ₆ refer to the drain end, and the second end refers to the source end. In addition, when other types of switches are selected, the first end is not limited to the 汲 extreme, and the second end is not limited to the source end.

In addition, each of the foregoing open relationships may be operated in different work areas, such as on and off, by control signals output by one or more controllers (not shown). Thereby, by controlling the respective switches to operate under different operating conditions, the bidirectional power converter of the present invention can have multiple operating modes, which are described as follows:

As shown in FIG. 2, when the bidirectional power converter 100 operates in a first mode (also referred to as a forward boost mode), the output signal controls the fifth switch Q ₅ and the sixth switch Q ₆ to Turning off the state, and switching the third switch Q ₃ and the fourth switch Q ₄ in an interleaved manner, and performing switching control on the first switch Q ₁ and the second switch Q ₂ in a synchronous rectification manner. At this time, it is in a state of dual energy supply, that is, the battery 10 is discharged together with the ultracapacitor 30 to the DC bus bar 20.

As can be seen from FIG. 3, in the forward boost mode, the battery 10 and the ultracapacitor 30 are discharged, and since the bidirectional power converter 100 adopts an interleaved switching operation, the current flowing into the DC busbar can be effectively reduced. Libo. Further, by simultaneously inputting the electric energy discharged from the battery 10 and the ultracapacitor 30 and boosting it by 650 V or more via the bidirectional power converter 100, the problem of the response or insufficient energy of the conventional fuel cell in the electric vehicle system can be effectively compensated.

The steady state analysis can be derived that the gain of the bidirectional power converter 100 (Conversion Gain) is as follows (1): Where k is defined as the ratio between the two input voltage sources, V _s1 =V _BT , V _s2 =V _UC . The conversion ratio of the voltage V _H of the DC bus 20 to each input voltage can be further derived by the following equations (2) and (3): Where D _{u is} defined as the duty cycle of the third switch Q ₃ and the fourth switch Q ₄ .

Please also cooperate with the conversion ratio diagram shown in FIG. 4A and FIG. 4B. As the figure shows, as the duty cycle D _u increases, or the battery 10 voltage (V _s1 = V _BT ) and the ultracapacitor 30 (V _s2 = V _UC ) When the ratio is increased, the conversion ratio between the voltage of the DC bus 20 and the battery 10 and the ultracapacitor 30 is also increased. Preferably, the duty cycle D _u of the third switch Q ₃ and the fourth switch Q ₄ can be set to be greater than 50%, and a better energy conversion ratio can be obtained.

As shown in FIG. 5, when the bidirectional power converter 100 operates in a second mode (also referred to as a reverse buck mode), the output signal controls the fifth switch Q ₅ and the sixth switch Q ₆ to be cut off. a state, and performing switching control on the first switch Q ₁ and the second switch Q ₂ in an interleaved manner, and performing switching control on the third switch Q ₃ and the fourth switch Q ₄ in a synchronous rectification manner. At the time of charging, the dual energy source is charged, that is, the DC bus bar 20 charges the battery 10 and the ultracapacitor 30.

As can be seen from FIG. 6, in the reverse buck mode, the DC bus 20 can charge the battery 10 and the ultracapacitor 30. Therefore, when the motor brakes, the voltage of the DC bus 20 rises rapidly, and the instantaneous high current. After inrush, it can be sucked by the ultracapacitor 30 Received. In addition, when the vehicle is idling or decelerating, the excess energy released by the other fuel cell should be supplied to the battery 10 or the ultracapacitor 30 for storage.

In addition, the interleaving switching operation of the bidirectional power converter 100 can effectively reduce the current ripple flowing out of the DC bus bar 20, and the charging current supplied to the battery 10 and the ultracapacitor 30 can also be stable. Continuous waveform.

The steady-state analysis can be derived that the gain of the bidirectional power converter 100 (Conversion Gain) is as follows (4): Where k is defined as the ratio between the two input voltage sources, V _s1 =V _BT , V _s2 =V _UC . The conversion ratio of each input voltage to the DC bus 20 voltage V _H can be further derived by the following equations (5) and (6): Where D _{d is} defined as the duty cycle of the first switch Q ₁ and the second switch Q ₂ .

Please also refer to the conversion ratio relationship diagram shown in FIGS. 7A and 7B. As can be seen from the figure, as the duty cycle D _d decreases, or the battery 10 voltage (V _s1 = V _BT ) and the ultracapacitor 30 voltage (V _s2 = V _When the ratio of _UC ) is increased, the step-down conversion ratio of the voltage of the DC bus 20 to the battery 10 and the ultracapacitor 30 is also increased, that is, the voltage of the DC bus 20 is transmitted through the bidirectional power converter 100 of the present invention to obtain a lower voltage. Level. Preferably, the duty cycle D _d of the first switch Q ₁ and the second switch Q ₂ can be set to be less than 50%, and a better energy conversion ratio can be obtained.

As shown in FIG. 8 and FIG. 9 , when the bidirectional power converter 100 is operated in a third mode, the output signal controls the first switch Q ₁ , the second switch Q ₂ , the fourth switch Q _{4 ,} and The sixth switch Q _{6 is} in an off state, at which time the DC bus 20 is in an offline mode, and then the fifth switch Q _{5 is} driven by a pulse width modulation signal, and the third switch Q _{3 is} used for synchronous rectification. At this time, the battery 10 can be made to release energy and be stored in the ultracapacitor 30.

The fifth switch Q ₅ and the sixth switch Q ₆ form a bidirectional switch. When the fifth switch Q _{5 is} turned on and the sixth switch Q _{6 is} turned off, the current flows through the diode in the sixth switch Q ₆ to The ultracapacitor 30 is stored.

In addition, as shown in FIG. 8 and FIG. 10, when the bidirectional power converter 100 is operated in a fourth mode, the output signal controls the first switch Q ₁ , the second switch Q ₂ , and the fourth switch Q. ₄ and the fifth switch Q _{5 is} in an off state, at which time the DC bus 20 is in an offline mode, and then the third switch Q _{3 is} driven by a pulse width modulation signal, and synchronized by the sixth switch Q ₆ For rectification, at this time, the ultracapacitor 30 can perform boosting, energy release, and energy storage in the battery 10.

Wherein, when the sixth switch Q _{6 is} turned on and the fifth switch Q _{5 is} turned off, current flows through the diodes in the fifth switch Q ₅ to store energy to the battery 10 .

It is worth mentioning that the driving signal for driving each of the switches adopts a Pulse-Width Modulation signal. Preferably, in this embodiment, the interleaved pulse width modulation is used (Interleaved). The Pulse-Width Modulation signal is preferred, but in other embodiments, other types of control signals or other types of pulse width modulation signals may be selected according to actual needs, instead of the interleaved pulse width modulation described above. The signal is limited.

In addition, between the two-phase circuits of the bidirectional power converter 100, that is, between the second end of the second switch Q _{2 and} the first end of the fourth switch Q ₄ , the clamping capacitor C _B is coupled The clamp capacitor C _B can be equivalent to a stable DC voltage source in the steady state operation state of the bidirectional power converter 100, thereby suppressing the two-phase circuit (the first switch Q ₁ and the second switch Q ₂ , the third The voltage surge of the switches of the switch Q ₃ and the fourth switch Q ₄ ) causes the voltage stress of the switch to be clamped to a lower range and reduces the switching loss of the switch to improve the overall efficiency of the converter.

It is to be noted that the bidirectional power converter of the present invention can be used in conjunction with a detector (not shown), wherein the detector is electrically connected to the driver for detecting the driver. An operating state, and returning the operating state to a processor or a controller (such as the aforementioned controller), and the processor or the controller correspondingly switches the switches of the bidirectional power converter according to the operating state of the driver control.

For example, when the driver is activated, upgraded, or accelerated, the bidirectional power converter 100 can be controlled to operate in the first mode, that is, to control the fifth switch Q ₅ and the sixth switch Q _{6 to be} in an off state. And switching the third switch Q ₃ and the fourth switch Q ₄ in an interleaved manner, and performing switching control on the first switch Q ₁ and the second switch Q ₂ in a synchronous rectification manner; thereby The battery 10 and the ultracapacitor 30 supply energy to the DC bus bar 20.

In addition, when the driver is under load or deceleration, the bidirectional power converter 100 can be controlled to operate in the second mode, that is, the fifth switch Q ₅ and the sixth switch Q _{6 are controlled to be} in an off state, and are alternately switched. The first switch Q ₁ and the second switch Q ₂ are switched and controlled, and the third switch Q ₃ and the fourth switch Q ₄ are switched and controlled in a synchronous rectification manner; thereby the DC bus bar 20 is reversely recovered. The energy is charged to the battery 10 and the ultracapacitor 30.

In addition, the DC power converter 100 can be controlled to operate in the third mode or the fourth mode when the DC bus is in an offline mode. In the third mode, the first switch Q ₁ , the second switch Q ₂ , the fourth switch Q _{4 ,} and the sixth switch Q _{6 are controlled to be} in an off state, and are driven by a pulse width modulation signal. The fifth switch Q ₅ is synchronously rectified by the third switch Q ₃ , so that the battery 10 is energy-discharged and stored in the ultracapacitor 30 . In the fourth mode, the first switch Q ₁ , the second switch Q ₂ , the fourth switch Q _{4 ,} and the fifth switch Q _{5 are controlled to be} in an off state, and are driven by a pulse width modulation signal. The third switch Q ₃ is synchronously rectified by the sixth switch Q ₆ , so that the ultracapacitor 30 is energy-discharged and stored in the battery 10 .

Thereby, the bidirectional power converter of the present invention can effectively reduce the chopping of the DC bus of the motor driver through the circuit structure and operation method of the above bidirectional power converter and integrating the control of the interleaved pulse width modulation signal. Effects and contribute to the gain boost of the buck/buck converter, as well as the ability to properly manage dual power energy management and distribution.

The above is only a preferred embodiment of the present invention. The two-way power converter of the present invention can be applied to ships, aircrafts and the like in addition to vehicles, but is not limited thereto. For example, in the field of related power conversion of a distributed renewable energy (wind energy, geothermal energy, solar energy, etc.) system, a bidirectional power converter such as the present invention can be applied without limitation in the field of mobile vehicles. The bidirectional power converter of the invention has high conversion efficiency, meets the current application range and development trend of the green energy industry, and is also quite beneficial to the national energy conservation policy.

Equivalent changes in the scope of the present invention and the scope of the claims are intended to be included within the scope of the invention.

100‧‧‧Bidirectional power converter

10‧‧‧Battery

20‧‧‧DC busbar

30‧‧‧Supercapacitors

Claims (14)

a bidirectional power converter for coupling between a battery, an ultracapacitor and a driver; the battery has a positive terminal and a negative terminal; the driver has a DC bus bar, and the DC bus bar has a positive And the second end of the battery includes: a first switch having a first end and a second end, and a second end of the first switch electrically connected to a positive end of the battery; The second switch has a first end and a second end, and the first end of the second switch is electrically connected to the positive end of the DC bus, and the second end of the second switch is opposite to the first switch The first end is electrically connected; the third end has a first end and a second end, and the second end of the third switch is electrically connected to the negative end of the battery and the negative end of the DC bus. In addition, the third switch is connected in parallel with the super capacitor; a fourth switch has a first end and a second end, and the first end of the fourth switch is electrically connected to the second end of the first switch, a second end of the fourth switch and a negative end of the battery, the DC bus a fifth switch having a first end and a second end, the first end of the fifth switch being electrically connected to the second end of the first switch; and a sixth switch having a first end and a second end, the first end of the sixth switch is electrically connected to the first end of the third switch, and the second end of the sixth switch is electrically connected to the second end of the fifth switch And a clamping capacitor, one end of which is electrically connected to the second end of the second switch, and the other end is electrically connected to the first end of the third switch. The bidirectional power converter of claim 1, further comprising a filter inductor, one end of which is electrically connected to the second end of the first switch, and the other end and the first end of the fifth switch, the positive end of the battery Electrical connection. The bidirectional power converter of claim 1, wherein when the bidirectional power converter operates in a first mode, the fifth switch and the sixth switch are controlled to be in an off state, and are interleaved The third switch and the fourth switch perform switching control, and perform switching control on the first switch and the second switch in a synchronous rectification manner; thereby causing the battery and the ultracapacitor to discharge the DC bus bar. The bidirectional power converter of claim 3, wherein the third switch and the fourth switch have a duty cycle greater than 50%. The bidirectional power converter of claim 3 or 4, wherein the third switch and the fourth switch are controlled by an interlaced pulse width modulation signal. The bidirectional power converter of claim 1, wherein when the bidirectional power converter operates in a second mode, the fifth switch and the sixth switch are controlled to be in an off state, and are interleaved The first switch and the second switch perform switching control to perform switching control on the third switch and the fourth switch in a synchronous rectification manner; thereby causing the DC bus to charge the battery and the ultracapacitor. The bidirectional power converter of claim 6, wherein the first switch and the second switch have a duty cycle of less than 50%. The bidirectional power converter of claim 6 or 7, wherein the first switch and the second switch are controlled by an interlaced pulse width modulation signal. The bidirectional power converter of claim 1, wherein when the bidirectional power converter operates in a third mode, the first switch, the second switch, the fourth switch, and the sixth switch are controlled to be cut off. The state drives the fifth switch with a pulse width modulation signal, and the third switch performs synchronous rectification, so that the battery is energy-discharged and stored in the ultracapacitor. The bidirectional power converter of claim 1, wherein when the bidirectional power converter operates in a fourth mode, the first switch, the second switch, the fourth switch, and the fifth switch are controlled to be cut off. a state, and driving the third switch with a pulse width modulation signal, and performing synchronous rectification with the sixth switch, so that the ultracapacitor is energy-released and stored in the battery. The bidirectional power converter of claim 1, wherein the first switch, the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch are respectively a metal oxide semiconductor field The first terminal is a drain of a metal oxide semiconductor field effect transistor, and the second ends are respectively sources of the metal oxide semiconductor field effect transistor. A method for operating a bidirectional power converter according to claim 1, comprising the steps of: A: detecting an operating state of the driver; B, making a bidirectional power converter according to an operating state of the driver One of the following steps: B1. When the driver is started, upgraded or accelerated, the bidirectional power converter operates in a first mode, and controls the fifth switch and the sixth switch to be in an off state, and is interleaved. Switching the switch to the third switch and the fourth switch, and performing switching control on the first switch and the second switch in a synchronous rectification manner; thereby causing the battery and the ultracapacitor to supply energy to the DC bus B2, when the driver is under load or deceleration, the bidirectional power converter operates in a second mode, and controls the fifth switch and the sixth switch to be in an off state, and the interlaced manner is used to a switch and the second switch perform switching control, and perform switching control on the third switch and the fourth switch in a synchronous rectification manner; thereby recovering the reverse Flow energy bus and the battery and to charge the super capacitor. The method of operating a bidirectional power converter according to claim 12, wherein when the bidirectional power converter operates in a third mode, the first switch, the second switch, the fourth switch, and the sixth are controlled The turn-off state is turned on, and the fifth switch is driven by the pulse width modulation signal, and the third switch is synchronously rectified, so that the battery is energy-discharged and stored in the ultracapacitor. The method of operating a bidirectional power converter according to claim 12, wherein when the bidirectional power converter operates in a fourth mode, the first switch, the second switch, the fourth switch, and the fifth are controlled The turn-off state is turned on, and the third switch is driven by the pulse width modulation signal, and the sixth switch is synchronously rectified, so that the ultracapacitor is energy-released and stored in the battery.