There are two types of technical indicators for power supplies such as sockets and switches: one is electrical technical parameters, including allowable input voltage, output voltage, output current and output voltage adjustment range, etc.; the other is quality indicators, used to scale M output The degree of stability of the DC voltage, including the voltage stabilization coefficient, output resistance, temperature coefficient and ripple voltage, etc. The meaning of these quality indicators is briefly described below.
1. Electrical technical parameters of switch power supply
(1) The number of phases and frequency of the input power supply. According to the different output power, the switching power supply “T adopts single-phase or three-phase power supply. When the output power is higher than 5kW, it usually uses three-phase power supply to balance the three-phase load.
(2) Input the allowable voltage fluctuation range of the rated voltage. The rated phase voltage of my country’s industrial frequency power supply is 220V, and the line voltage is 380V. The rated output power must be guaranteed within the allowable voltage fluctuation range.
(3) Rated input current. Rated input current refers to the input current at rated input voltage and rated output power.
(4) Maximum input current. The maximum input current refers to the input current at the allowable lower limit input voltage and rated output power.
(5) Input power factor. Input power factor refers to the ratio of input active power to apparent power.
(6) Rated output DC voltage (nominal output DC voltage). The rated output DC voltage refers to the maximum output DC voltage when the specified voltage regulation accuracy and ripple index are met under the state of the rated output current.
(7) Output voltage ripple and noise. The output voltage ripple refers to the AC component in the output that is synchronized with the input power frequency, and is expressed by the peak value. Noise refers to AC components other than ripple in the output, and is also represented by peak values. It is also commonly used to denote the magnitude of the AC component in the output by subtracting the peak value of the AC component in the output from the sum of the ripple and noise.
(8) Rated output current. The rated output current refers to the maximum average current supplied to the load at the rated output voltage.
(9) Efficiency. Efficiency refers to the ratio of output active power to input active power.
2. Quality indicators of sockets and switches supply
(1) Voltage regulation rate. Voltage regulation rate is an important indicator of the performance of switching power supply voltage regulation, also known as voltage regulation coefficient or stability coefficient: it characterizes the degree of stability of the output voltage R of the switching power supply when the input voltage changes, usually in the unit output voltage The relative change of input and output voltage is expressed as a percentage.
(2) Current regulation rate. The current regulation rate is a main indicator that reflects the load capacity of the switching power supply, and is also called the current stability coefficient. It characterizes the ability of the switching power supply to suppress the fluctuation of the output voltage caused by the change of the load current when the input voltage is constant. Under the condition of the specified load current change, the current regulation rate of the switching power supply is usually expressed as the percentage of the output voltage change value under the unit output voltage.
(3) Ripple suppression ratio. The ripple rejection ratio reflects the ability of the switching power supply to suppress the mains voltage introduced by the input terminal. When the input and output conditions of the switching power supply remain unchanged, the ripple rejection ratio of the switching power supply is usually expressed as the ratio of the peak-to-peak input ripple voltage to the peak-to-peak output ripple voltage, and is generally expressed in decibels, but sometimes it can Expressed as a percentage, or directly expressed by the ratio of the two.
(4) Temperature stability. The temperature stability of the integrated switching power supply is expressed by the percentage value of the relative change of the output voltage of the switching power supply within the maximum change range of the specified switching power supply operating temperature.
3. Working indicators of sockets and switches supply
The working index of the sockets and switches power supply refers to the working area where the sockets and switches supply can work normally and the working conditions necessary to ensure normal work. These operating indicators depend on the performance of the components constituting the switching power supply.
(1) Output voltage range. The output voltage range refers to the output voltage range within which the switching power supply can work normally under the condition that it meets the working conditions of the switching power supply. The upper limit of this index is determined by the maximum input voltage and the minimum input-output voltage difference, and its lower limit is determined by the internal reference voltage value of the switching power supply.
(2) Large input and output voltage difference. This indicator characterizes the voltage difference between the maximum input and output allowed by the switching power supply under the condition of ensuring the normal operation of the sockets and switches supply. This value mainly depends on the withstand voltage index of the internal adjustment tube of the switching power supply.
(3) The minimum input and output voltage difference. This indicator characterizes the minimum input-output voltage difference required by the sockets and switches supply under the condition of ensuring the normal operation of the switching power supply.
(4) Output load current range. The output load current range is also called the output current range. Within this current range, the switching power supply should be able to ensure compliance with the index requirements given in the index specifications.
4. Limit parameters of sockets and switches supply
(1) Maximum input voltage. This voltage is the maximum input voltage that guarantees the safe operation of the switching power supply.
(2) Maximum output current. This current is the maximum output current allowed to ensure the safe operation of the switching power supply.
sockets and switches
5. Protection parameters of sockets and switches supplies
(1) Overcurrent protection. This is a power supply load protection function to avoid damage to the power supply and the load by the overload output current including the short circuit on the output terminal. The given value of overcurrent is generally 110% ~130% of the rated current.
(2) Overvoltage protection. This is a function of load protection for excessive voltage between terminals. Overvoltage is generally specified as 130% ~ 150% of the nominal voltage.
(3) Output undervoltage protection. Output under-voltage protection means that when the output voltage is below the standard value, it detects the output voltage drop or stops the sockets and switches supply and sends an alarm signal to protect the load and prevent misoperation. The output undervoltage is mostly 80% ~ 30% of the output voltage.
In addition, there are indicators that reflect the dynamic characteristics of the system, such as dynamic voltage drop and modulation time when a load is suddenly applied, as well as electromagnetic interference and radio frequency interference indicators for sockets and switches supply. Different application occasions have different requirements for the sockets and switches supply. Therefore, when designing a switching power supply, the technical index requirements for the power supply should be determined according to the specific situation, and then the converter structure of Herui should be selected and the design of relevant parameters should be completed.