Protection apparatus and brushless motor system

A brushless motor system comprising:

• an armature winding, a rectifier circuit, an excitation winding, an excitation power supply circuit, a transformer, a controller, and a protection apparatus, wherein
• an input terminal of the excitation power supply circuit is configured to connect to a direct current power supply, and an output terminal of the excitation power supply circuit is connected to a primary side of the transformer;
• a secondary side of the transformer is connected to an input terminal of the rectifier circuit;
• the protection apparatus is separately connected to the rectifier circuit, the excitation winding, the excitation power supply circuit, and the controller;
• and
• the armature winding is connected to the controller;
• wherein the protection apparatus comprises a demagnetization apparatus and a control apparatus, wherein
• the demagnetization apparatus is configured to be bridged between the rectifier circuit and the excitation winding, and is configured to consume, when the brushless motor system is faulty, excess electric energy generated on the excitation winding;
• and
• the control apparatus is configured to separately connect to the excitation power supply circuit and the controller;
• and is configured to detect electrical parameters of an input terminal and an output terminal of the excitation power supply circuit, and when determining that the electrical parameters are outside of a threshold range, generate an alarm to the controller and adjust the output electrical parameter of the excitation power supply circuit.