TW201547168A - Digital AC/DC power converter - Google Patents

Abstract

A digital AC/DC power converter adopts a micro-controller to output PWM signal so as to control the ON/OFF state of a single switch module, thus achieving high power factor correction. The micro-controller dynamically control a duty cycle of the PWM signal based on at least one voltage/current feedback information.

Description

Digital AC/DC Power Converter

The invention relates to a digital AC/DC power converter, in particular to designing an innovative AC/DC power converter using a digital microcontroller, so that the power factor of the AC/DC power converter is effective improve.

The power factor of the power converter is defined as the ratio of the power actually delivered to the load to the power provided by the power source, and the power converter should be capable of transmitting power from the power source to the load with high power factors.

Recently, government agencies have gradually adopted regulations requiring power factors of power converters to exceed a certain minimum level. For example, the US Energy Star requires that if the size of a device needs to exceed 49 watts, the power factor of the power converter needs to be at least 87%, such as a notebook computer. On the other hand, the US Energy Star requires that if the size of a device requires no more than 5 watts, the power factor of the power converter can reach 68%, such as a mobile phone.

In general, Power Factor Correction (PFC) can be achieved by the use of specific analog circuits (ICs) specifically designed for use in power converters to improve PFC. In addition, each analog IC used to improve PFC is designed differently in different application areas, so there is a lack of a general-purpose architecture to accommodate designs in different application areas.

At this stage, if a device requires more than 60 watts of power, its power factor correction function is usually achieved through the use of a specific analog IC in the power converter. However, if a device does not require more than 65 W of power, the device typically does not have a power correction factor function, since the price of the power converter with the aforementioned analog IC to improve power factor correction will be approximately equal to or at least twice as low as not available. Power converter corrected power converter price.

Furthermore, the implementation of the aforementioned conventional power converters typically requires complex circuitry and considerable effort is required to stabilize the complex circuitry. Also, in different applications, power converters require different specific analog ICs to achieve high power factor correction.

In summary, a power conversion using a general-purpose digital microprocessor with a simple circuit to provide a high PFC is highly desirable, and the digital microprocessor provides a pulse width modulation (PWM) signal for use. To control the power converter. The aforementioned digital microprocessor providing the PWM signal can be regarded as a digital PWM controller.

In view of this, it is necessary to provide a digital AC/DC power converter that is designed with a microprocessor and is used to provide a high PFC.

A digital AC/DC power converter comprising:

An active power factor correction module;

a single switch module, comprising a single switch, the switch being electrically connected to the active power factor correction module;

a power output module comprising a transformer, the main side coil of the transformer being electrically connected to the active power factor correction module;

a digital control module comprising a microcontroller, the microcontroller providing a pulse width modulation signal for controlling a switching state of the single switch, such that the active power factor correction module will be lower than The 300 Hz AC frequency is converted to a frequency of at least 30,000 Hz, and a rectified AC output voltage waveform is outputted to the power output module to increase the power factor. A digital AC/DC power converter comprising:

An active power factor correction module;

a single switch module, comprising a single switch, the switch being electrically connected to the active power factor correction module;

a power output module includes a transformer, a first switch and a second switch, wherein a main side coil of the transformer is electrically connected to the active power factor correction module;

a digital control module comprising a microcontroller, the microcontroller providing a pulse width modulation signal for controlling a switching state of the single switch, such that the active power factor correction module will be lower than The 300 Hz AC frequency is converted to a frequency of at least 30,000 Hz, and a rectified AC output voltage waveform is outputted to the power output module to increase the power factor.

The invention will now be further described with reference to the specific embodiments thereof with reference to the accompanying drawings.

Figure 1 is a comparison of an analog PWM controller with a digital PWM controller.

2 is a functional block diagram of a low power digital AC/DC power converter in accordance with an embodiment of the present invention.

3 is a circuit diagram of a low power digital AC/DC power converter in accordance with an embodiment of the present invention.

4 is a functional block diagram of a /high power digital AC/DC power converter in accordance with an embodiment of the present invention.

Figure 5 is a circuit diagram of a power digital AC/DC power converter in accordance with one embodiment of the present invention.

6 is a circuit diagram of a high power digital AC/DC power converter in accordance with an embodiment of the present invention.

7 is a soft switching timing diagram of a power digital AC/DC power converter in accordance with an embodiment of the present invention.

8 is a soft switching timing diagram of a high power digital AC/DC power converter in accordance with an embodiment of the present invention.

The embodiments of the present invention and FIGS. 1 through 8 will be described in the following, and the component symbols will be used in the various drawings to assist in explaining the details of the embodiments.

1 is a comparison diagram of the difference between an analog PWM controller and a digital PWM controller according to an embodiment of the present invention. Referring to FIG. 1, an analog PWM controller 101 generally has an error comparison unit 103, a calculation comparison unit 105, a ramp generator 107, a latch unit 109, and a drive unit 111. In addition, a power converter can generally have the analog PWM controller 101, a switch module 113, and auxiliary circuits 115 and 117.

The error comparison unit 103 has an amplifier and thus has a positive terminal receiving a reference voltage and a negative terminal receiving a feedback voltage, the feedback voltage being provided by the auxiliary circuit 115. If the feedback voltage is higher than the reference voltage, no error is eliminated. The feedback voltage is formed by a voltage dividing circuit having resistors R ₁₀₁ , R ₁₀₂ , the voltage dividing circuit is located in the auxiliary circuit 115 , and the auxiliary circuit 115 has a capacitor C ₁₀₁ and a resistor R _{103 .} A RC circuit is formed, thus providing an oscillating average of the output waveform to the error comparison unit 103.

The calculation comparison unit 105 has an amplifier and thus has a forward end for receiving an output signal from the ramp generator, and a negative end for receiving an integrated signal, the integrated signal is The output signal of the error comparison unit 103 is formed by the output signal of the auxiliary circuit 117. The auxiliary circuit 117 is a RC circuit and also receives an output signal from the auxiliary circuit 115.

The calculation comparison unit 105 uses a comparison method to obtain a change in pulse width, and outputs an approximate-width variable-width pulse signal. Next, the latch unit 109 receives the variable width pulse signal and outputs a variable width rectangular pulse to the driving unit 111 for amplifying the variable width pulse signal. Typically, the output signal of the driving unit 111 is an amplified variable width rectangular pulse, and the voltage of the output signal needs to be higher than 5V to appropriately drive the switch module 113. The switch module 113 has at least one switching component, such as a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) or an Insulated Gate Bipolar Transistor (IGBT). And controlling the DC output of the power converter.

On the other hand, referring to FIG. 1, a digital PWM controller 131 generally has a power management unit 133, a control interface 135, a digital reference voltage unit 137, and an analog/digital converter (A/D converter; ADC) 139. A digital adder 141, a digital PID filter 143, and a digital PWM unit 145. In addition, a power converter can generally have the digital PWM controller 131, a driving unit 147, a switch module 149, and an auxiliary circuit 151.

The control interface 135 has an SDA interface for data communication and an SCL interface for time/frequency communication. Accordingly, the digital reference voltage unit 136 is a signal that can receive signals from the power management unit 133 and from the control interface 135, thereby outputting a digital reference voltage to the digital adder 141. The digital adder 141 receives the signal from the analog/digital converter 139 and the signal from the digital reference voltage unit 137. The analog/digital converter 139 is convertible to a digital amount. For example, an analog 1V signal can be converted by the analog/digital converter 139 to a digital signal of 0 to 255, where the digital 0 represents 0V and digit 1 represents 1V. Further, the analog / digital converter 139 receives a line by the resistor R5, the voltage division formed by R6, the resistor R _05, R ₀₆ lines located within the booster circuit 151.

After the calculation by the digital adder 141, the digital adder 141 outputs a signal to the digital PID filter 143, and the digital PID filter 143 outputs an approximate rectangular variable width pulse signal. Next, the digital PWM unit 145 receives the variable width pulse signal and outputs a variable width rectangular pulse to the driving unit 147 for amplifying the variable width pulse signal, so that the driving The unit 147 can appropriately drive the switch module 149. The switch module 149 has at least one switching element, such as a MOSFET or an IGBT, and controls the DC output of the power converter.

Compared to power converters with analog PWM controllers, power converters with digital PWM controllers can be implemented in the following ways: multiple interfaces/pins to handle analog/digital conversion, multisampling and centralized control, flexibility, Better complex controls such as intelligent control or high precision control, and overall cost.

2 is a block diagram of a low power digital AC/DC power converter in accordance with an embodiment of the present invention. Referring to FIG. 2, a digital power converter has a rectification and filtering module 201, an active power factor correction (PFC) module 203, a single switch module 205, a power output module 207, and a digital control module 209. .

In FIG. 2, the power transmission direction is from an AC input to a DC output, and sequentially passes through the rectification and filtering module 201, the active PFC module 203, and the power output module 207.

The rectification and filtering module 201 is electrically connected to the AC input, the active PFC module 203, and the digital control module 209. The active PFC module 203 is electrically coupled to the rectification and filtering module 201 , the power output module 207 , and the digital control module 209 . The power output module 207 is electrically connected to the DC output, the active PFC module 203, and the digital control module 209. The single switch module 205 is electrically connected to the active PFC module 203 and the digital control module 209.

The digital control module 209 provides an amplified PWM signal _Spwm to the single switch module 205 for controlling the switch ON/OFF switching state. Thus, the single switch module 205 can output a digital PWM. Signaling to the active PFC module 203. In addition, the single switch module 205 provides a feedback signal I _protect to control the output of the amplified PWM signal _Spwm , thus avoiding potential damage to the single switch.

The rectification and filtering module 201 provides an enable signal to the digital control module 209 to activate the digital AC/DC power converter. The power output module 207 provides a wake-up signal to the digital control module 209 to wake up the digital AC/DC power converter. In addition, the power output module 207 provides an internal voltage of a digital power converter as a feedback signal to the digital control module 209, so that the digital control module 209 detects the internal voltage and can control the The duty cycle of the amplified PWM signal S _{pwm is} described.

3 is a circuit diagram of the low power digital power converter to describe more details in FIG. 2, in accordance with an embodiment of the present invention. Referring to FIG. 3, the rectifying and filtering module 201 has a varistor R ₃₀₀ , a fuse S ₃₀₁ , a full bridge rectifier BR ₁ , an electromagnetic interference filter EF , capacitors C ₃₀₀ and C ₃₀₁ , and a start signal. Line 301. It should be noted here that the rectification and filtering module 201 is connected to an AC power source for providing an AC input.

Typically, the frequency of the alternating current input is between 50 and 60 Hz, and the alternating current input is electrically connected to the varistor R ₃₀₀ and the fuse S ₃₀₁ . The varistor R ₃₀₀ is for providing overvoltage protection, and the fuse S ₃₀₁ is for providing overcurrent protection. The full-bridge rectifier BR ₁ is arranged in a bridge shape by four diodes to achieve full-wave rectification, and converts the alternating current input into a rectified voltage waveform. The electromagnetic interference filter EF is used to block electromagnetic waves that can be regarded as noise.

The capacitor C ₃₀₁ is used to smooth the voltage waveform fluctuation of the rectified by the full bridge rectifier BR ₁ . However, the capacitance C _{301 has} a capacity selected to be less than 1 μF and preferably 200 nF to 300 nF, so that only a small portion of the valley of the rectified voltage waveform is filled, and thus the capacity due to the large capacitance C _{301 is} avoided. Caused by low power factor correction.

In order to reduce standby power consumption of the digital power converter, the enable signal line 301 to obtain a signal from the half-bridge, the half-bridge portion of claim ₁ is based full-bridge rectifier BR. Therefore, the signal from node N ₀ is a half-wave rectified signal and is filtered by capacitor C ₃₀₁ . The filtered signal in the enable signal line 301 is supplied to an auxiliary integrated circuit 303. When the digital power converter is electrically connected to the alternating current input, a starting current is formed immediately and transmitted to the auxiliary integrated circuit 303 by the node N ₀ via the starting signal line 301, thus causing the digit The power converter is working.

In FIG. 3, the active PFC module 203 has a booster circuit, a π-type filter and a voltage divider circuit. The step-up circuit is formed by an inductor L ₃₀₁ , diodes D ₃₀₁ and D ₃₀₂ , and the π-type filter is formed by an inductor L ₃₀₂ , capacitors C ₃₀₂ and C ₃₀₃ , and the voltage divider The circuit is formed by resistors R ₃₀₁ , R ₃₀₂ and R ₃₀₃ .

In the active PFC module 203, the diode D ₃₀₂ can be regarded as a switch, and the switch is electrically connected to a power MOSFET P ₃₀₁ located in the single switch module 205, and the diode D ₃₀₂ is controlled by the digital control module 209 electrically connected to the power MOSFET P ₁ . When the diode D _{302 is} switched to the "on" state, the voltage on the left side of the inductor L ₃₀₁ is higher than the voltage on the right side thereof, thus storing energy into one of the cores surrounded by the inductor L ₃₀₁ . When the diode D _{302 is} switched to the "off" state, the voltage on the left side of the inductor L ₃₀₁ is lower than the voltage on the right side thereof, so the energy stored in the core is released through the inductor L ₃₀₁ . In addition, the diodes D ₃₀₁ and D ₃₀₂ may be high frequency diodes.

In the active PFC module 203, when the diode D _{301 is} turned on, the voltage on the left side of the diode D ₃₀₁ is higher than the voltage on the right side thereof, so the energy from the boost circuit is stored. To the capacitors C ₃₀₂ and C ₃₀₃ .

Basically, the energy stored in capacitors C ₃₀₂ and C ₃₀₃ is used to fill most of the valleys of the rectified voltage waveform. It should be noted that the rectified voltage waveform can be regarded as a low frequency envelope of a high frequency waveform, and the high frequency waveform is created by the amplified PWM signal _Spwm , and the amplified PWM signal S _Pwm is provided by the digital control module 209. Of the amplified PWM signal S _pwm diode D by the control switch _302, will be lower than the frequency into a frequency of at least 300Hz of 30,000Hz, wherein the frequency is less than 300Hz is of the frequency of the AC input. For example, the frequency of the amplified PWM signal can be 60,000 Hz. Therefore, the switching of the diode D ₃₀₂ can change the rectified voltage waveform from a low frequency state to a high frequency state, creating a rectified AC output voltage waveform having a high frequency.

The voltage dividing circuit formed by the resistors R ₃₀₁ , R ₃₀₂ and R ₃₀₃ is configured to enable the microcontroller 305 in the digital control module 209 to detect the internal voltage of the digital power converter . When the microcontroller 305 so that when the power MOSFET P ₁ does not work, the internal voltage lines can be equal to the ratio of the AC input voltage of the power source. When the microcontroller 305 causes the power MOSFET P _{301 to operate} , the internal voltage can be proportional to the voltage boosted by the boost circuit.

For example, when the power MOSFET P _{301 is in} operation, the microcontroller can detect a peak voltage boosted via the boost circuit. If the peak voltage is above a certain threshold, the duty cycle of the power MOSFET P ₃₀₁ switch will be adjusted by the microcontroller 305. The resistance values of resistors R ₃₀₁ and R ₃₀₂ can be in the range of 10 ⁵ to 10 ⁷ Ω, and the resistors R ₃₀₁ and R ₃₀₂ need to tolerate at least 440V.

In FIG. 3, the single switch module 205 has the power MOSFET P ₃₀₁ and resistors R ₃₀₄ , R ₃₀₅ and R ₃₀₆ , and the power MOSFET P _{301 is} a single switch. The resistor R ₃₀₄ is electrically connected to the source of the power MOSFET P ₃₀₁ and is also electrically connected to the auxiliary integrated circuit 303 . Additionally, the resistor R ₃₀₄ is used to sample current flowing through the source of the power MOSFET P ₃₀₁ . If the current flowing through the source of the power MOSFET P ₃₀₁ is greater than a certain threshold, the digital control module 205 will not output or reduce the PWM signal, thus protecting the power MOSFET P ₃₀₁ .

The resistor R ₃₀₅ is electrically connected to the gate of the power MOSFET P ₃₀₁ and is also electrically connected to the auxiliary integrated circuit 303. In addition, the resistor R ₃₀₄ is used to transmit the PWM signal provided by the digital control module 209. The resistor R ₃₀₆ is electrically connected to the gate of the power MOSFET P ₃₀₁ and is also grounded, thereby avoiding the false conduction of the power MOSFET P ₃₀₁ .

In FIG. 3, the power output module 207 has a transient voltage suppressor (TVS) D ₃₀₃ , a freewheeling diode (FWD) D ₃₀₄ , and a main side N _p and a a transformer TR of a first side N _s1 and a second side N _s2 , a photoelectric coupling circuit, wherein the photoelectric coupling circuit is composed of a capacitor L ₁ , resistors R ₃₀₈ , R ₃₀₉ , R ₃₁₀ , and an optocoupler The device OC ₁ , a diode D ₃₀₆ and a capacitor C ₃₀₈ are formed. In addition, the first measurement N _s1 is electrically connected to a diode D ₃₀₅ , has a resistance R ₃₀₇ and a capacitor C ₃₀₄ one of the resistance capacitance circuits, and the capacitors C ₃₀₅ , C ₃₀₆ , C ₃₀₇ . The second secondary side N _s2 is electrically connected to a diode D ₇ and a capacitor C ₃₁₀ . It should be noted here that the power output module 207 further includes a capacitor C ₃₀₉ and is coupled to the DC load to provide a DC output.

The transient diode D ₃₀₃ and the freewheeling diode D ₃₀₄ form an absorption circuit. When the power MOSFET P _{301 is} switched to the "on" state, one of the cores surrounded by the main side of the transformer TR stores the energy transferred from the active PFC module 203. When the power MOSFET P _{301 is} switched to the "off" state, the magnetic core surrounded by the main side of the transformer TR releases energy transferred from the active PFC module 203, thus the The transient diode D ₃₀₃ and the freewheeling diode D ₃₀₄ absorb the energy and reverse the magnetic lines of force of the core surrounded by the primary side. Due to the aforementioned energy absorption, the transient diode D ₃₀₃ and the freewheeling diode D ₃₀₄ dissipate heat and eliminate transient high frequency pulses.

The transformer TR is used to convert the voltage from the active PFC module 203 and provide isolation between the AC input and the DC output. The diode D ₃₀₅ is for rectifying a signal output from the first secondary side N _s1 . The resistor-capacitor circuit having the resistor R ₃₀₇ and the capacitor C ₃₀₄ is for absorbing high-frequency pulses, and the capacitors C ₃₀₅ , C ₃₀₆ , C ₃₀₇ are used for filtering, thus reducing from the first The _chopping within the signal output by the secondary side N _s1 . In addition, the second secondary side N _s2 is used to provide an operating voltage to the digital control module 209. For example, the auxiliary IC 303 can receive the operating voltage provided by the second secondary side N _s2 , wherein the operating voltage can be 4 to 5V.

The optocoupler circuit is composed of the capacitor L ₃₀₃ , the resistors R ₃₀₈ , R ₃₀₉ , R ₃₁₀ , the photocoupler OC ₃₀₁ , the diode D _{306 ,} and a capacitor C ₃₀₈ . The resistors R ₃₀₈ and R ₃₀₉ are used for voltage limiting, and the resistors R ₃₀₉ and R ₃₁₀ form a voltage divider. The diode D ₃₀₆ is used for precision regulation. If the voltage provided by the voltage divider formed by the resistors R ₃₀₉ and R ₃₁₀ is higher than a certain threshold, the diode D ₆ will switch to the "on"state; The voltage provided by the voltage divider formed by the resistors R ₃₀₉ and R ₃₁₀ is lower than the specified threshold, and the diode D ₃₀₆ will switch to the "off" state. Therefore, the diode D ₃₀₆ determines whether the photocoupler OC ₃₀₁ generates light. If the voltage between the resistor R ₃₀₈ and the diode D ₃₀₆ is higher than a certain threshold, the photocoupler OC ₃₀₁ generates light, thus providing a feedback signal proportional to the output voltage to a micro Controller 305.

In FIG. 3, the digital control module 209 has the microcontroller 305, the auxiliary integrated circuit 301, and an optical coupling circuit. The optical coupling circuit includes an optical coupler OC ₂ , resistors R ₁₁ , and R. ₁₂ and a capacitor C ₁₃ are formed.

The auxiliary integrated circuit 303 can be regarded as a power management and driving integrated circuit. The integrated circuit 303 having auxiliary pins 1 to 7, wherein pin 1 of the system for sensing the activation signal, pin 2 of the system for sensing a power MOSFET P ₁ of the gate current, pin 3 Is used to provide an amplified PWM signal to the power MOSFET P ₁ , the pin 4 is used to obtain the operating voltage from the second secondary side N _s2 , and the pin 5 is used to receive the slave microcontroller The PWM signal from 305 is used to communicate with the microcontroller 305, and the pin 7 is used to provide the voltage at which the microcontroller 305 operates. In addition, the communication via the pin 6 can be two-way communication, and can include detecting an error signal of the auxiliary integrated circuit 303, and confirming whether the auxiliary integrated circuit 303 is in a normal operating mode.

On the other hand, the microcontroller 305 has pins 8-15, wherein the pin 8 is for receiving the operating voltage supplied from the auxiliary integrated circuit 303, and the pin 9 is used for the auxiliary product. The body circuit 303 communicates, the pin 10 is used to provide the PWM signal to the auxiliary integrated circuit 303, the pin 11 is used for detecting the internal voltage of the digital power converter, and the pin 12 is used for grounding. The pin 13 is reserved for other purposes, the pin 14 is for receiving a wake-up signal fed back from the digital output module 207, and the pin 15 is for receiving the photoelectric coupling from the digital control module 209. A signal of a circuit that represents the output voltage.

In addition, the wake-up signal is transmitted via a wake-up signal line 307 designed for micro power standby. When the load connected to the DC output is in a system shutdown state, the micro power standby design can reduce the load power consumption from the original 1~3W power consumption to not more than 100mW power consumption. Thus, if the voltage of the DC output has a small change, such as a 100 mV change caused by USB insertion, the microcontroller 305 will be woken up by the wake-up signal.

Due to the design of the power output module 207, the digital AC/DC power converter of FIG. 3 can be considered as a flyback power converter. In addition, the digital AC/DC power converter of FIG. 3 can also be modified to an analog AC/DC power converter that replaces the digital control module 209 with an analog control module and provides the same control functions. The analog control module can include an analog controller for providing a PWM signal to control the active PFC module 203 and the power output module 207. Therefore, the circuit structure of FIG. 3 can adopt the analog control module or the digital control module 209; if the analog control module is used, the cost can be further reduced.

4 is a block diagram of a medium/high power AC/DC digital power converter in accordance with an embodiment of the present invention. Referring to FIG. 4, a digital power converter has a rectification and filtering module 401, an active PFC module 403, a single switch module 405, a power output module 407, and a digital control module 409. The main difference between FIG. 2 and FIG. 4 is that the digital control module 409 provides an additional control signal S _switch to the power output module 407 for intelligent control to achieve zero voltage switch (ZVS). Quasi-resonant soft switching design, especially in medium/high power applications, such as 80 to 200W medium power applications or high power applications greater than 200W.

5 is a schematic diagram of the medium power digital power converter, in accordance with an embodiment of the present invention. The main difference between FIG. 5 and FIG. 3 is that the power output module 407 of FIG. 5 is different from the power output module 207 of FIG.

Referring to FIG. 5, the power output module 407 includes two switches M ₅₀₁ , M ₅₀₂ connected in series to the ground. A microcontroller 505 controls an auxiliary IC 503 to output a non-synchronized rectangular pulse from the pins A1, A2 for controlling the switches M ₅₀₁ , M ₅₀₂ such that when the switch M _{501 is} switched to the "on" state, The switch M _{502 is} maintained in an "off"state; when the switch M _{502 is} switched to an "on" state, the switch M _{501 is} maintained in an "off" state. Therefore, the switches M ₅₀₁ and M ₅₀₂ alternately operate in opposite switch states. In addition, due to the grounding, the switches M ₅₀₁ and M ₅₀₂ cannot be turned on at the same time. Preferably, the switches M ₅₀₁ and M ₅₀₂ can be MOSFETs.

In the power output module 407, a transformer TR has a main side coil N _p , a first side coil N _s1 and a second side coil N _s2 . The left side of the main side coil N _p is electrically connected to the switches M ₅₀₁ , M ₅₀₂ , and the right side of the main side coil N _p is electrically connected to the two capacitors C ₅₀₄ , C ₅₀₅ .

When the switch M _{501 is} in the "on" state and the switch M _{502 is} in the "off" state, the main side coil N _p draws energy from the capacitors C ₅₀₄ , C ₅₀₅ at this time. The left side of the main side coil N _p is at a high potential, the right side is at a low potential, and the right side voltage is about 1/2 times the left side voltage. At this point, the transformer core stores energy.

When the switch M _{501 is} in the "on" state and the switch M _{502 is} in the "off" state, if the switch M _{501 is} switched to the "off" state, the main side coil N _p will be caused. The left side is at a low potential, the right side is at a high potential, and the left side voltage is about 1/2 times the right side voltage. At this time, the switches M ₅₀₁ and M ₅₀₂ are both in the "off" state.

M ₅₀₁ when the switch is in the "OFF" state of M ₅₀₂ and the switch in the "OFF" of the state, when the switch M ₅₀₂ is switched to "open" the state will result in the primary side coil N _p The left side is at zero potential and the right side is at high potential, thus changing the energy storage direction of the transformer core. Since the magnetic field direction of the foregoing method can be quickly flipped, the magnetic core is not easily saturated, so the working frequency, the core utilization rate and the energy conversion efficiency can be improved.

Next, when the switch M _{501 is} in the "off" state and the switch M _{502 is} in the "on" state, if the switch M _{502 is} switched to the "off" state, the switch M is prepared. ₅₀₁ switches to the "on" state to achieve a complete control loop, as shown in FIG. Thus, the next step is to switch the switch M ₅₀₁ to the "on" state, while the switch M _{501 is} in the "on" state and the switch M _{502 is} in the "off" state.

Furthermore, the output power module 407 comprises two inductance L ₅₀₃ and L _504, the inductor L ₅₀₃ and the system for storing the excess energy is released, the inductor L ₅₀₃ then use as a core with a filter. The power output module 407 further includes a sampling circuit SC ₅₀₁ for voltage sampling for constant voltage applications or current sampling for constant current applications.

Therefore, the design of the power output module 407 receives the intelligent control of the microcontroller 505, so that the digital power converter of the embodiment is a quasi-resonant of a half bridge zero voltage switch (ZVS). Quasi-resonant) soft switching design.

6 is a schematic diagram of the high power digital power converter, in accordance with an embodiment of the present invention. The main difference between FIG. 6 and FIG. 5 is that in the high power embodiment, the power output module 607 of FIG. 6 is different from the power output module 507 of FIG. 5.

Referring to FIG. 6 , the power output module 607 includes four switches M ₆₀₁ , M ₆₀₂ , M ₆₀₃ , and M ₆₀₄ , and the switches M ₆₀₃ and M ₆₀₄ are used to replace the capacitors C ₅₀₄ and C _{505 of} FIG. 5 . In the power output module 607, the switches M ₆₀₁ , M ₆₀₄ operate simultaneously, and the switches M ₆₀₂ , M ₆₀₃ operate simultaneously.

A microcontroller 605 controls an auxiliary IC 603 to output unsynchronized rectangular pulses from pins A1, A2, A3, A4 for controlling the switches M ₆₀₁ , M ₆₀₂ , M ₆₀₃ , M ₆₀₄ such that when the switch M when _601, M ₆₀₄ to switch to the "on" state, the switch M _602, M ₆₀₃ is maintained in the "off"state; when the switch M _602, M ₆₀₃ to switch to the "on" state, the switch M ₆₀₁ and M _{604 are} maintained in the "off" state. Therefore, the switches M ₆₀₁ , M ₆₀₄ and M ₆₀₂ , M ₆₀₃ alternately operate in opposite switch states. Preferably, the switches M ₆₀₁ , M ₆₀₂ , M ₆₀₃ , M ₆₀₄ may be IGBTs.

In the power output module 607, a transformer TR has a primary side coil N _p , a first secondary side coil N _s1 and a second secondary side coil N _s2 . The left side of the main side coil N _p is electrically connected to the switches M ₆₀₁ , M ₆₀₂ , and the right side of the main side coil N _p is electrically connected to the switches M ₆₀₃ , M ₆₀₄ . In addition, the right side of the main side coil N _p is also electrically connected to a capacitor C ₆₀₄ for isolating the DC signal.

When the switches M ₆₀₁ , M ₆₀₄ are in the "on" state and the switches M ₆₀₂ , M ₆₀₃ are in the "off" state, the left side of the main side coil N _p is at a high potential and the right side is low. Potential. Next, if the switches M ₆₀₁ and M _{604 are} switched to the "off" state, the left side of the main side coil N _p is at a low potential, and the right side is at a high potential. At this time, the switches M ₆₀₁ , M ₆₀₂ , M ₆₀₃ , and M ₆₀₄ are all in the "off" state.

When the switches M ₆₀₁ , M ₆₀₂ , M ₆₀₃ , and M ₆₀₄ are all in the "off" state, if the switches M ₆₀₂ and M _{603 are} switched to the "on" state, the main side coil N _p is caused. The left side is at zero potential and the right side is at high potential, thus changing the energy storage direction of the transformer core. Since the magnetic field direction of the foregoing method can be quickly flipped, the magnetic core is not easily saturated, so the working frequency, the core utilization rate and the energy conversion efficiency can be improved.

Next, when the switches M ₆₀₁ , M ₆₀₄ are in the "off" state and the switches M ₆₀₂ , M ₆₀₃ are in the "on" state, if the switches M ₆₀₂ , M _{603 are} switched to "off" The state is to switch the switches M ₆₀₁ and M ₆₀₄ to the "on" state to achieve a complete control loop, as shown in FIG.

Therefore, the design of the power output module 607 receives the intelligent control of the microcontroller 605, so that the digital power converter of the embodiment is a full bridge zero voltage switch (ZVS) quasi-resonance. (quasi-resonant) soft switching design.

Microcontroller 305,505,605 preceding embodiments embodiment, the system may employ eight yuan of digital microprocessor, the duty cycle of the amplified PWM signal S _pwm of (duty cycle) to expand at least 64 times the accuracy to Accurately control the increase or decrease of the work cycle. For example, if the voltage of the DC output is too large, it can be controlled by the digital microprocessor to reduce the duty cycle of _Spwm . If the voltage of the DC output is too small, it can be controlled by the digital microprocessor to increase _Spwm. Work cycle. The software can realize the precision expansion through the digital microprocessor, which can effectively save the cost of the overall digital AC/DC power converter and accurately control the duty cycle of the PWM.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and those skilled in the art will be able to make equivalent modifications or variations in accordance with the spirit of the present invention. It should be covered by the following patent application.

101, ‧‧‧ analog PWM controller

103‧‧‧Error comparison unit

105‧‧‧Computation and comparison unit

107‧‧‧ ramp generator

109‧‧‧Latch unit

111,147‧‧‧ drive unit

113,149‧‧‧ switch module

115,117,151‧‧‧Auxiliary circuit

R _{1 0 1} , R _{1 0 2} , R _{1 0 3} ‧‧‧resist

C _{1 0 1} ‧‧‧ capacitor

131‧‧‧Digital PWM Controller

133‧‧‧Power Management Unit

135‧‧‧Control interface

137‧‧‧Digital reference voltage unit

139‧‧‧ Analog/Digital Converter

141‧‧‧Digital Adder

143‧‧‧Digital PID Filter

145‧‧‧Digital PWM unit

201,401‧‧‧Rectifier and Filter Module

203, 403‧‧‧Active Power Factor Correction Module

205,405‧‧‧ single switch module

207,407‧‧‧Power output module

209,409‧‧‧Digital Control Module

301,501,601‧‧‧Start signal line

303,503,603‧‧‧Auxiliary IC

305, 505, 605‧ ‧ microcontroller

307,507,607‧‧‧Wake-up signal line

R _{3 0 0} , R _{5 0 0} , R _{6 0 0} ‧‧‧ varistor

S _{3 0 1} , S _{5 0 1} , S _{6 0 1} ‧‧‧Fuse

BR ₁ ‧‧‧ Full Bridge Rectifier

EF‧‧ EMI filter

C _{3 0 0 ~ 3 1 4} , C _{5 0 0 ~ 5 0 8} , C _{6 0 0 ~ 6 0 8} ‧‧‧ Capacitance

L _{3 0 1 ~ 3 0 3} , L _{5 0 1 ~ 5 0 4} , L _{6 0 1 ~ 6 0 4} ‧‧‧Inductance

D _{3 0 1 ~ 3 0 8} , D _{5 0 1 ~ 5 0 4} , D _{6 0 1 ~ 6 0 4} TR‧‧‧ Diode Transformer

OC ₁ , OC ₂ ‧‧‧optocoupler

P _{3 0 1} , P _{5 0 1} , P _{6 0 1} ‧‧‧Power MOSFET

M _{5 0 1 ~ 5 0 2} , M _{6 0 1 ~ 6 0 4} ‧‧‧ Switch

SC _{5 0 1} , SC _{6 0 1} ‧‧‧Sampling circuit

no

201‧‧‧Rectifier and Filter Module

203‧‧‧Active PFC Module

205‧‧‧Single switch module

207‧‧‧Power output module

209‧‧‧Digital Control Module

Claims (21)

A digital AC/DC power converter comprising:
An active power factor correction module;
a single switch module, comprising a single switch, the switch being electrically connected to the active power factor correction module;
a power output module includes a transformer, a main side coil of the transformer is electrically connected to the active power factor correction module, and a digital control module includes a microcontroller, the micro control The device provides a pulse width modulation signal for controlling the switching state of the single switch, so that the active power factor correction module converts an AC frequency lower than 300 Hz into a frequency of at least 30,000 Hz, and outputs a rectified The AC output voltage waveform is applied to the power output module to increase the power factor. The digital AC/DC power converter of claim 1, wherein the microcontroller can be a digital microprocessor having at least 8 bits for adjusting the duty cycle of the pulse width modulation signal. Increase the accuracy by at least 64 times. The digital AC/DC power converter of claim 2, wherein the digital control module further comprises an auxiliary integrated circuit, the microcontroller providing a pulse width modulation signal to the auxiliary integrated body a circuit, the auxiliary integrated circuit amplifies the pulse width modulation signal and provides the single switch module to control a switching state of the single switch. The digital AC/DC power converter of claim 2, wherein the power output module further comprises a transient diode and a freewheeling diode, the transient diode and the freewheeling diode The pole body is electrically connected to the main side coil of the transformer and is used to dissipate heat and eliminate transient high frequency pulses. The digital AC/DC power converter of claim 2, wherein the transformer of the power output module further comprises a primary side coil for providing an operating voltage to the digital control module. The digital AC/DC power converter of claim 2, wherein the power output module provides a wake-up signal to the digital control module to wake up the digital AC/DC power converter. The digital AC/DC power converter of claim 2, further comprising a rectifying and filtering module, the rectifying and filtering module comprising a full bridge rectifier and a capacitor of less than 1 μF, the capacitor And a method for smoothing a voltage waveform trough rectified by the full bridge rectifier and electrically connecting to the active power factor correction module. The digital AC/DC power converter of claim 6, wherein the rectifying and filtering module provides a start signal to the digital control module to activate the digital AC/DC power converter. The digital power factor correction module of claim 2, wherein the active power factor correction module comprises a booster circuit and a π-type filter, the booster circuit according to the single The switching of the switch module switches the control energy output to the π-type filter. The digital power factor correction module of claim 2, wherein the active power factor correction module includes a voltage dividing circuit for providing an internal voltage to the digital control module, The digital control module controls the duty cycle of the pulse width modulation signal according to the internal voltage. A digital AC/DC power converter comprising:
An active power factor correction module;
a single switch module, comprising a single switch, the switch being electrically connected to the active power factor correction module;
a power output module includes a transformer, a first switch and a second switch, wherein a main side coil of the transformer is electrically connected to the active power factor correction module; and a digital control module a microcontroller is provided, and the microcontroller provides a pulse width modulation signal for controlling a switching state of the single switch, so that the active power factor correction module converts an AC frequency lower than 300 Hz into at least A frequency of 30,000 Hz, and outputting a rectified AC output voltage waveform to the power output module to increase the power factor. The digital AC/DC power converter of claim 11, wherein the microcontroller controls the first switch and the second switch through the auxiliary integrated circuit, when the first switch is switched to " When the state is "on", the second switch is maintained in an "off" state; when the second switch is switched to an "on" state, the first switch is maintained in an "off" state. The digital AC/DC power converter of claim 12, wherein the power output module further includes a third switch and a fourth switch, and the fourth switch is controlled by the auxiliary integrated circuit The first switch is synchronously switched to the same switch state, and the third switch and the second switch are synchronously switched to the same switch state. The digital AC/DC power converter of claim 11 to 13, wherein the microcontroller can be a digital microprocessor having at least 8 bits for modulating the pulse width signal. The duty cycle is increased by at least 64 times the accuracy. The digital AC/DC power converter of claim 14, wherein the digital control module further comprises an auxiliary integrated circuit, the microcontroller providing a pulse width modulation signal to the auxiliary integrated body a circuit, the auxiliary integrated circuit amplifies the pulse width modulation signal and provides the single switch module to control a switching state of the single switch. The digital AC/DC power converter of claim 14, wherein the transformer of the power output module further comprises a primary side coil for providing an operating voltage to the digital control module. The digital AC/DC power converter of claim 14, wherein the power output module provides a wake-up signal to the digital control module to wake up the digital AC/DC power converter. The digital AC/DC power converter of claim 14, further comprising a rectifying and filtering module, the rectifying and filtering module comprising a full bridge rectifier and a capacitor of less than 1 μF, the capacitor And a method for smoothing a voltage waveform trough rectified by the full bridge rectifier and electrically connecting to the active power factor correction module. The digital AC/DC power converter of claim 18, wherein the rectifying and filtering module provides a start signal to the digital control module to activate the digital AC/DC power converter. The digital power factor correction module of claim 14, wherein the active power factor correction module comprises a booster circuit and a π-type filter, the booster circuit according to the single The switching of the switch module switches the control energy output to the π-type filter. The digital power factor correction module of claim 14, wherein the active power factor correction module includes a voltage dividing circuit for providing an internal voltage to the digital control module, The digital control module controls the duty cycle of the pulse width modulation signal according to the internal voltage.