Why does my VESC stop connecting to PC when turns on a DC power supply?

Posted by Christina Zhang on

Why does my VESC stop connecting to PC when turns on a DC switch power supply? (the light is off, there is no response, and the computer cannot be connected)

What is switch power supply? (regulated power supply PSU)

The definition of a switching power supply is an electronic device that converts and regulates the voltage of electrical power.

PSU power supply, switching power supply, regulated power supplyPSU power supply, switching power supply, regulated power supplyPSU power supply, switching power supply, regulated power supply

What's the difference of battery and switch power supply (PSU)?

1. The difference is that the battery has a higher impedance, especially at the frequencies you are using, than the nicely regulated power supply.

2. A battery will output most of the time a constant voltage. A PSU converts 110/220 AC voltage into your 5VDC (or whatever voltage), and that process isn't perfect, so a PSU can't output trully constante voltage. 

Details: 

When connect switch power supply to AC power, it will turn AC to DC first. The instantaneous power of the switching power supply is about 300V, and then the switching power supply adjusts the voltage to the specified voltage (such as 20V, 35V). Most switching power supplies respond slowly, and the 300V voltage at the instant of powering will directly burn the ESC driver, MCU, Causes capacitance expansion, etc.)

Turn on the power first (such as setting 35V), and then connect the load. If the load is too large, the voltage will drop (30V). At this time, the switching power supply will increase the voltage to the specified value (35V). But because the load constantly changes. If the load becomes smaller at this time, it will cause the instantaneous voltage to become higher and may burn out the ESC. For example, when the power is turned on, the capacitor will charge quickly. At this time, the voltage will drop, and the switching power supply must be pressurized to maintain the set value, but the capacitor will not continue to charge after it is fully charged. At this time, the actual voltage of the switching power supply is higher than the set value, etc. It senses that there is a certain time difference when it is reduced to the set value, and the ESC may burn out during this time. 

Its’ a characteristic of Switching power supply called transient response.

So when use ESCs/VESCs, especially at high voltage, please use battery for test rather than DC switch power supply to protect the ESCs.


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