History of power adapters
Power adapter, can not be separated from our lives, such as mobile phone charger, mobile power, LED lighting, etc., we discuss the history, background, research scope, current status, future development direction and current controversy focus of the power adapter, the purpose of the research Meaning, importance.
At the end of the 19th century, Thomas Edison successfully used a direct current transmission to light up the light bulb, but because of the huge energy loss, the efficiency of direct current transmission is very low. In 1957, JenSen invented the self-excited push-pull double transformer. In 1964, American scientists proposed the elimination of the series power adapter of the power frequency transformer, which made the power supply a fundamental way to reduce the volume and weight. . Later, Nikolates invented the AC transmission, which replaced the DC transmission.
In 1969, due to the improvement of the withstand voltage of high-power silicon transistors and the shortening of the diode reverse recovery time, the 25 kHz power adapter was finally realized.
Later, with the application of power MOSFETs, the switching frequency of the power adapter was further increased, resulting in a smaller power supply, lighter weight, and higher power density.
Today, although the voltage and frequency used are different, AC transmission has been widely adopted in countries all over the world. The power supply frequency is 50Hz or 60Hz, and the power supply voltage is 100V to 240V. Power adapters offer significant advantages over most performance metrics compared to linear power supplies. Therefore, in addition to the extremely high ripple requirements of the DC output voltage, the power adapter has completely replaced the linear power supply. The power supply of computers, televisions, and various electronic instruments is almost always the power adapter.
As a power supply for electronic devices, linear power supplies are mainly used in a small power range. Therefore, before the 1980s, as a replacement for linear power supplies, power adapters were also mainly used in low-power applications. At that time, the medium and large power DC power supply was still dominated by thyristor phase control power supply. However, since the 1980s, the emergence of insulated gate bipolar transistors (IGBTs) has broken this pattern.
The IGBT can be seen as a device in which a MOSFET and a BJT are combined. Like BJT, they are mainly used in medium power applications, but IGBTs have a higher operating frequency and are voltage-driven devices that are easy to drive and have outstanding advantages without obvious disadvantages. Therefore, IGBTs quickly replaced the short-lived BJT, becoming the mainstream device in the medium power range, and constantly expanding its living space in the direction of high power.
The advent of IGBTs has led to an ever-increasing capacity of power adapters, quickly replacing phase-controlled power supplies in many medium-capacity ranges. In the field of communications, the early 48V base power supply almost all used thyristor phase-controlled power supply, and has now been gradually replaced by power adapters. The DC power supply for the operation of the power system used to be a thyristor phase-controlled power supply. At present, the power adapter has become its mainstream. In addition, the application range of conventional thyristor phase-controlled power supplies such as electric welding machines and electroplating devices is gradually being eaten by power adapters.
As mentioned above, the increase of the switching frequency can reduce the power supply volume and reduce the weight, but the switching loss is increased and the power supply efficiency is lowered. In addition, the increase in switching frequency also makes the electromagnetic interference problem of the power supply stand out. In order to solve this problem, a zero-voltage switching circuit and a zero-current switching circuit using quasi-harmonic technology appeared in the 1980s. This technology is called soft switching technology. The soft switching technology can reduce the switching loss to zero under ideal conditions, improve the efficiency, and also greatly reduce the electromagnetic interference, thus helping to further increase the switching frequency, making the power supply further smaller, lighter and more efficient. The development of power density is large. After nearly 20 years of development, research on soft switching technology is still very active, and it has become a basic technology applied to various power electronic circuits. However, to date, the most successful area of soft switching technology applications is still in the field of power adapters.
The circuit between the power adapter and the AC grid is usually a diode rectifier circuit. The input current of this circuit is no longer a sine wave and contains a large number of harmonics, which also makes the power factor of the power supply very low. When there is a large amount of power adapter load on the utility grid, it will cause serious harmonic pollution to the power grid. The term "green power" has often been heard in recent years. The "green" mentioned here mainly means that it does not generate harmonic pollution to the power grid, does not cause electromagnetic interference to the environment, and of course includes no noise. In order to reduce the harmonic pollution of the power adapter to the power grid and improve the power factor of the power adapter, Power Factor Correction (PFC) technology appeared in the 1990s and was widely used in various power adapters. At present, single-phase PFC technology is relatively mature and widely used in various power adapters, while three-phase PFC technology has a long way to go.
The development direction of modern power adapter technology is from the traditional power adapter technology, which mainly deals with low-frequency technology, to the modern power adapter, which is mainly based on high-frequency technology. Power electronics began in the late 1950s and early 1960s, and its development has experienced the era of rectifiers, inverters and inverters, and has promoted the application of power adapter technology in many new fields. In the future, the power supply will be changed from a separate module to a module that can interact with other circuits to actively adjust its work according to the change of the load, to achieve perfect efficiency, further reduce heat and reactive power consumption.... and achieve stronger Adaptability.
At the end of the 19th century, Thomas Edison successfully used a direct current transmission to light up the light bulb, but because of the huge energy loss, the efficiency of direct current transmission is very low. In 1957, JenSen invented the self-excited push-pull double transformer. In 1964, American scientists proposed the elimination of the series power adapter of the power frequency transformer, which made the power supply a fundamental way to reduce the volume and weight. . Later, Nikolates invented the AC transmission, which replaced the DC transmission.
In 1969, due to the improvement of the withstand voltage of high-power silicon transistors and the shortening of the diode reverse recovery time, the 25 kHz power adapter was finally realized.
Later, with the application of power MOSFETs, the switching frequency of the power adapter was further increased, resulting in a smaller power supply, lighter weight, and higher power density.
Today, although the voltage and frequency used are different, AC transmission has been widely adopted in countries all over the world. The power supply frequency is 50Hz or 60Hz, and the power supply voltage is 100V to 240V. Power adapters offer significant advantages over most performance metrics compared to linear power supplies. Therefore, in addition to the extremely high ripple requirements of the DC output voltage, the power adapter has completely replaced the linear power supply. The power supply of computers, televisions, and various electronic instruments is almost always the power adapter.
As a power supply for electronic devices, linear power supplies are mainly used in a small power range. Therefore, before the 1980s, as a replacement for linear power supplies, power adapters were also mainly used in low-power applications. At that time, the medium and large power DC power supply was still dominated by thyristor phase control power supply. However, since the 1980s, the emergence of insulated gate bipolar transistors (IGBTs) has broken this pattern.
The IGBT can be seen as a device in which a MOSFET and a BJT are combined. Like BJT, they are mainly used in medium power applications, but IGBTs have a higher operating frequency and are voltage-driven devices that are easy to drive and have outstanding advantages without obvious disadvantages. Therefore, IGBTs quickly replaced the short-lived BJT, becoming the mainstream device in the medium power range, and constantly expanding its living space in the direction of high power.
The advent of IGBTs has led to an ever-increasing capacity of power adapters, quickly replacing phase-controlled power supplies in many medium-capacity ranges. In the field of communications, the early 48V base power supply almost all used thyristor phase-controlled power supply, and has now been gradually replaced by power adapters. The DC power supply for the operation of the power system used to be a thyristor phase-controlled power supply. At present, the power adapter has become its mainstream. In addition, the application range of conventional thyristor phase-controlled power supplies such as electric welding machines and electroplating devices is gradually being eaten by power adapters.
As mentioned above, the increase of the switching frequency can reduce the power supply volume and reduce the weight, but the switching loss is increased and the power supply efficiency is lowered. In addition, the increase in switching frequency also makes the electromagnetic interference problem of the power supply stand out. In order to solve this problem, a zero-voltage switching circuit and a zero-current switching circuit using quasi-harmonic technology appeared in the 1980s. This technology is called soft switching technology. The soft switching technology can reduce the switching loss to zero under ideal conditions, improve the efficiency, and also greatly reduce the electromagnetic interference, thus helping to further increase the switching frequency, making the power supply further smaller, lighter and more efficient. The development of power density is large. After nearly 20 years of development, research on soft switching technology is still very active, and it has become a basic technology applied to various power electronic circuits. However, to date, the most successful area of soft switching technology applications is still in the field of power adapters.
The circuit between the power adapter and the AC grid is usually a diode rectifier circuit. The input current of this circuit is no longer a sine wave and contains a large number of harmonics, which also makes the power factor of the power supply very low. When there is a large amount of power adapter load on the utility grid, it will cause serious harmonic pollution to the power grid. The term "green power" has often been heard in recent years. The "green" mentioned here mainly means that it does not generate harmonic pollution to the power grid, does not cause electromagnetic interference to the environment, and of course includes no noise. In order to reduce the harmonic pollution of the power adapter to the power grid and improve the power factor of the power adapter, Power Factor Correction (PFC) technology appeared in the 1990s and was widely used in various power adapters. At present, single-phase PFC technology is relatively mature and widely used in various power adapters, while three-phase PFC technology has a long way to go.
The development direction of modern power adapter technology is from the traditional power adapter technology, which mainly deals with low-frequency technology, to the modern power adapter, which is mainly based on high-frequency technology. Power electronics began in the late 1950s and early 1960s, and its development has experienced the era of rectifiers, inverters and inverters, and has promoted the application of power adapter technology in many new fields. In the future, the power supply will be changed from a separate module to a module that can interact with other circuits to actively adjust its work according to the change of the load, to achieve perfect efficiency, further reduce heat and reactive power consumption.... and achieve stronger Adaptability.
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